| /* Handle SVR4 shared libraries for GDB, the GNU Debugger. |
| |
| Copyright (C) 1990-2016 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| |
| #include "elf/external.h" |
| #include "elf/common.h" |
| #include "elf/mips.h" |
| |
| #include "symtab.h" |
| #include "bfd.h" |
| #include "symfile.h" |
| #include "objfiles.h" |
| #include "gdbcore.h" |
| #include "target.h" |
| #include "inferior.h" |
| #include "infrun.h" |
| #include "regcache.h" |
| #include "gdbthread.h" |
| #include "observer.h" |
| |
| #include "solist.h" |
| #include "solib.h" |
| #include "solib-svr4.h" |
| |
| #include "bfd-target.h" |
| #include "elf-bfd.h" |
| #include "exec.h" |
| #include "auxv.h" |
| #include "gdb_bfd.h" |
| #include "probe.h" |
| |
| static struct link_map_offsets *svr4_fetch_link_map_offsets (void); |
| static int svr4_have_link_map_offsets (void); |
| static void svr4_free_library_list (void *p_list); |
| |
| /* Link map info to include in an allocated so_list entry. */ |
| |
| struct lm_info |
| { |
| /* Amount by which addresses in the binary should be relocated to |
| match the inferior. The direct inferior value is L_ADDR_INFERIOR. |
| When prelinking is involved and the prelink base address changes, |
| we may need a different offset - the recomputed offset is in L_ADDR. |
| It is commonly the same value. It is cached as we want to warn about |
| the difference and compute it only once. L_ADDR is valid |
| iff L_ADDR_P. */ |
| CORE_ADDR l_addr, l_addr_inferior; |
| unsigned int l_addr_p : 1; |
| |
| /* The target location of lm. */ |
| CORE_ADDR lm_addr; |
| |
| /* Values read in from inferior's fields of the same name. */ |
| CORE_ADDR l_ld, l_next, l_prev, l_name; |
| }; |
| |
| /* On SVR4 systems, a list of symbols in the dynamic linker where |
| GDB can try to place a breakpoint to monitor shared library |
| events. |
| |
| If none of these symbols are found, or other errors occur, then |
| SVR4 systems will fall back to using a symbol as the "startup |
| mapping complete" breakpoint address. */ |
| |
| static const char * const solib_break_names[] = |
| { |
| "r_debug_state", |
| "_r_debug_state", |
| "_dl_debug_state", |
| "rtld_db_dlactivity", |
| "__dl_rtld_db_dlactivity", |
| "_rtld_debug_state", |
| |
| NULL |
| }; |
| |
| static const char * const bkpt_names[] = |
| { |
| "_start", |
| "__start", |
| "main", |
| NULL |
| }; |
| |
| static const char * const main_name_list[] = |
| { |
| "main_$main", |
| NULL |
| }; |
| |
| /* What to do when a probe stop occurs. */ |
| |
| enum probe_action |
| { |
| /* Something went seriously wrong. Stop using probes and |
| revert to using the older interface. */ |
| PROBES_INTERFACE_FAILED, |
| |
| /* No action is required. The shared object list is still |
| valid. */ |
| DO_NOTHING, |
| |
| /* The shared object list should be reloaded entirely. */ |
| FULL_RELOAD, |
| |
| /* Attempt to incrementally update the shared object list. If |
| the update fails or is not possible, fall back to reloading |
| the list in full. */ |
| UPDATE_OR_RELOAD, |
| }; |
| |
| /* A probe's name and its associated action. */ |
| |
| struct probe_info |
| { |
| /* The name of the probe. */ |
| const char *name; |
| |
| /* What to do when a probe stop occurs. */ |
| enum probe_action action; |
| }; |
| |
| /* A list of named probes and their associated actions. If all |
| probes are present in the dynamic linker then the probes-based |
| interface will be used. */ |
| |
| static const struct probe_info probe_info[] = |
| { |
| { "init_start", DO_NOTHING }, |
| { "init_complete", FULL_RELOAD }, |
| { "map_start", DO_NOTHING }, |
| { "map_failed", DO_NOTHING }, |
| { "reloc_complete", UPDATE_OR_RELOAD }, |
| { "unmap_start", DO_NOTHING }, |
| { "unmap_complete", FULL_RELOAD }, |
| }; |
| |
| #define NUM_PROBES ARRAY_SIZE (probe_info) |
| |
| /* Return non-zero if GDB_SO_NAME and INFERIOR_SO_NAME represent |
| the same shared library. */ |
| |
| static int |
| svr4_same_1 (const char *gdb_so_name, const char *inferior_so_name) |
| { |
| if (strcmp (gdb_so_name, inferior_so_name) == 0) |
| return 1; |
| |
| /* On Solaris, when starting inferior we think that dynamic linker is |
| /usr/lib/ld.so.1, but later on, the table of loaded shared libraries |
| contains /lib/ld.so.1. Sometimes one file is a link to another, but |
| sometimes they have identical content, but are not linked to each |
| other. We don't restrict this check for Solaris, but the chances |
| of running into this situation elsewhere are very low. */ |
| if (strcmp (gdb_so_name, "/usr/lib/ld.so.1") == 0 |
| && strcmp (inferior_so_name, "/lib/ld.so.1") == 0) |
| return 1; |
| |
| /* Similarly, we observed the same issue with sparc64, but with |
| different locations. */ |
| if (strcmp (gdb_so_name, "/usr/lib/sparcv9/ld.so.1") == 0 |
| && strcmp (inferior_so_name, "/lib/sparcv9/ld.so.1") == 0) |
| return 1; |
| |
| return 0; |
| } |
| |
| static int |
| svr4_same (struct so_list *gdb, struct so_list *inferior) |
| { |
| return (svr4_same_1 (gdb->so_original_name, inferior->so_original_name)); |
| } |
| |
| static struct lm_info * |
| lm_info_read (CORE_ADDR lm_addr) |
| { |
| struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| gdb_byte *lm; |
| struct lm_info *lm_info; |
| struct cleanup *back_to; |
| |
| lm = (gdb_byte *) xmalloc (lmo->link_map_size); |
| back_to = make_cleanup (xfree, lm); |
| |
| if (target_read_memory (lm_addr, lm, lmo->link_map_size) != 0) |
| { |
| warning (_("Error reading shared library list entry at %s"), |
| paddress (target_gdbarch (), lm_addr)), |
| lm_info = NULL; |
| } |
| else |
| { |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| |
| lm_info = XCNEW (struct lm_info); |
| lm_info->lm_addr = lm_addr; |
| |
| lm_info->l_addr_inferior = extract_typed_address (&lm[lmo->l_addr_offset], |
| ptr_type); |
| lm_info->l_ld = extract_typed_address (&lm[lmo->l_ld_offset], ptr_type); |
| lm_info->l_next = extract_typed_address (&lm[lmo->l_next_offset], |
| ptr_type); |
| lm_info->l_prev = extract_typed_address (&lm[lmo->l_prev_offset], |
| ptr_type); |
| lm_info->l_name = extract_typed_address (&lm[lmo->l_name_offset], |
| ptr_type); |
| } |
| |
| do_cleanups (back_to); |
| |
| return lm_info; |
| } |
| |
| static int |
| has_lm_dynamic_from_link_map (void) |
| { |
| struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| |
| return lmo->l_ld_offset >= 0; |
| } |
| |
| static CORE_ADDR |
| lm_addr_check (const struct so_list *so, bfd *abfd) |
| { |
| if (!so->lm_info->l_addr_p) |
| { |
| struct bfd_section *dyninfo_sect; |
| CORE_ADDR l_addr, l_dynaddr, dynaddr; |
| |
| l_addr = so->lm_info->l_addr_inferior; |
| |
| if (! abfd || ! has_lm_dynamic_from_link_map ()) |
| goto set_addr; |
| |
| l_dynaddr = so->lm_info->l_ld; |
| |
| dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic"); |
| if (dyninfo_sect == NULL) |
| goto set_addr; |
| |
| dynaddr = bfd_section_vma (abfd, dyninfo_sect); |
| |
| if (dynaddr + l_addr != l_dynaddr) |
| { |
| CORE_ADDR align = 0x1000; |
| CORE_ADDR minpagesize = align; |
| |
| if (bfd_get_flavour (abfd) == bfd_target_elf_flavour) |
| { |
| Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header; |
| Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr; |
| int i; |
| |
| align = 1; |
| |
| for (i = 0; i < ehdr->e_phnum; i++) |
| if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align) |
| align = phdr[i].p_align; |
| |
| minpagesize = get_elf_backend_data (abfd)->minpagesize; |
| } |
| |
| /* Turn it into a mask. */ |
| align--; |
| |
| /* If the changes match the alignment requirements, we |
| assume we're using a core file that was generated by the |
| same binary, just prelinked with a different base offset. |
| If it doesn't match, we may have a different binary, the |
| same binary with the dynamic table loaded at an unrelated |
| location, or anything, really. To avoid regressions, |
| don't adjust the base offset in the latter case, although |
| odds are that, if things really changed, debugging won't |
| quite work. |
| |
| One could expect more the condition |
| ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0) |
| but the one below is relaxed for PPC. The PPC kernel supports |
| either 4k or 64k page sizes. To be prepared for 64k pages, |
| PPC ELF files are built using an alignment requirement of 64k. |
| However, when running on a kernel supporting 4k pages, the memory |
| mapping of the library may not actually happen on a 64k boundary! |
| |
| (In the usual case where (l_addr & align) == 0, this check is |
| equivalent to the possibly expected check above.) |
| |
| Even on PPC it must be zero-aligned at least for MINPAGESIZE. */ |
| |
| l_addr = l_dynaddr - dynaddr; |
| |
| if ((l_addr & (minpagesize - 1)) == 0 |
| && (l_addr & align) == ((l_dynaddr - dynaddr) & align)) |
| { |
| if (info_verbose) |
| printf_unfiltered (_("Using PIC (Position Independent Code) " |
| "prelink displacement %s for \"%s\".\n"), |
| paddress (target_gdbarch (), l_addr), |
| so->so_name); |
| } |
| else |
| { |
| /* There is no way to verify the library file matches. prelink |
| can during prelinking of an unprelinked file (or unprelinking |
| of a prelinked file) shift the DYNAMIC segment by arbitrary |
| offset without any page size alignment. There is no way to |
| find out the ELF header and/or Program Headers for a limited |
| verification if it they match. One could do a verification |
| of the DYNAMIC segment. Still the found address is the best |
| one GDB could find. */ |
| |
| warning (_(".dynamic section for \"%s\" " |
| "is not at the expected address " |
| "(wrong library or version mismatch?)"), so->so_name); |
| } |
| } |
| |
| set_addr: |
| so->lm_info->l_addr = l_addr; |
| so->lm_info->l_addr_p = 1; |
| } |
| |
| return so->lm_info->l_addr; |
| } |
| |
| /* Per pspace SVR4 specific data. */ |
| |
| struct svr4_info |
| { |
| CORE_ADDR debug_base; /* Base of dynamic linker structures. */ |
| |
| /* Validity flag for debug_loader_offset. */ |
| int debug_loader_offset_p; |
| |
| /* Load address for the dynamic linker, inferred. */ |
| CORE_ADDR debug_loader_offset; |
| |
| /* Name of the dynamic linker, valid if debug_loader_offset_p. */ |
| char *debug_loader_name; |
| |
| /* Load map address for the main executable. */ |
| CORE_ADDR main_lm_addr; |
| |
| CORE_ADDR interp_text_sect_low; |
| CORE_ADDR interp_text_sect_high; |
| CORE_ADDR interp_plt_sect_low; |
| CORE_ADDR interp_plt_sect_high; |
| |
| /* Nonzero if the list of objects was last obtained from the target |
| via qXfer:libraries-svr4:read. */ |
| int using_xfer; |
| |
| /* Table of struct probe_and_action instances, used by the |
| probes-based interface to map breakpoint addresses to probes |
| and their associated actions. Lookup is performed using |
| probe_and_action->probe->address. */ |
| htab_t probes_table; |
| |
| /* List of objects loaded into the inferior, used by the probes- |
| based interface. */ |
| struct so_list *solib_list; |
| }; |
| |
| /* Per-program-space data key. */ |
| static const struct program_space_data *solib_svr4_pspace_data; |
| |
| /* Free the probes table. */ |
| |
| static void |
| free_probes_table (struct svr4_info *info) |
| { |
| if (info->probes_table == NULL) |
| return; |
| |
| htab_delete (info->probes_table); |
| info->probes_table = NULL; |
| } |
| |
| /* Free the solib list. */ |
| |
| static void |
| free_solib_list (struct svr4_info *info) |
| { |
| svr4_free_library_list (&info->solib_list); |
| info->solib_list = NULL; |
| } |
| |
| static void |
| svr4_pspace_data_cleanup (struct program_space *pspace, void *arg) |
| { |
| struct svr4_info *info = (struct svr4_info *) arg; |
| |
| free_probes_table (info); |
| free_solib_list (info); |
| |
| xfree (info); |
| } |
| |
| /* Get the current svr4 data. If none is found yet, add it now. This |
| function always returns a valid object. */ |
| |
| static struct svr4_info * |
| get_svr4_info (void) |
| { |
| struct svr4_info *info; |
| |
| info = (struct svr4_info *) program_space_data (current_program_space, |
| solib_svr4_pspace_data); |
| if (info != NULL) |
| return info; |
| |
| info = XCNEW (struct svr4_info); |
| set_program_space_data (current_program_space, solib_svr4_pspace_data, info); |
| return info; |
| } |
| |
| /* Local function prototypes */ |
| |
| static int match_main (const char *); |
| |
| /* Read program header TYPE from inferior memory. The header is found |
| by scanning the OS auxillary vector. |
| |
| If TYPE == -1, return the program headers instead of the contents of |
| one program header. |
| |
| Return a pointer to allocated memory holding the program header contents, |
| or NULL on failure. If sucessful, and unless P_SECT_SIZE is NULL, the |
| size of those contents is returned to P_SECT_SIZE. Likewise, the target |
| architecture size (32-bit or 64-bit) is returned to P_ARCH_SIZE and |
| the base address of the section is returned in BASE_ADDR. */ |
| |
| static gdb_byte * |
| read_program_header (int type, int *p_sect_size, int *p_arch_size, |
| CORE_ADDR *base_addr) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| CORE_ADDR at_phdr, at_phent, at_phnum, pt_phdr = 0; |
| int arch_size, sect_size; |
| CORE_ADDR sect_addr; |
| gdb_byte *buf; |
| int pt_phdr_p = 0; |
| |
| /* Get required auxv elements from target. */ |
| if (target_auxv_search (¤t_target, AT_PHDR, &at_phdr) <= 0) |
| return 0; |
| if (target_auxv_search (¤t_target, AT_PHENT, &at_phent) <= 0) |
| return 0; |
| if (target_auxv_search (¤t_target, AT_PHNUM, &at_phnum) <= 0) |
| return 0; |
| if (!at_phdr || !at_phnum) |
| return 0; |
| |
| /* Determine ELF architecture type. */ |
| if (at_phent == sizeof (Elf32_External_Phdr)) |
| arch_size = 32; |
| else if (at_phent == sizeof (Elf64_External_Phdr)) |
| arch_size = 64; |
| else |
| return 0; |
| |
| /* Find the requested segment. */ |
| if (type == -1) |
| { |
| sect_addr = at_phdr; |
| sect_size = at_phent * at_phnum; |
| } |
| else if (arch_size == 32) |
| { |
| Elf32_External_Phdr phdr; |
| int i; |
| |
| /* Search for requested PHDR. */ |
| for (i = 0; i < at_phnum; i++) |
| { |
| int p_type; |
| |
| if (target_read_memory (at_phdr + i * sizeof (phdr), |
| (gdb_byte *)&phdr, sizeof (phdr))) |
| return 0; |
| |
| p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, |
| 4, byte_order); |
| |
| if (p_type == PT_PHDR) |
| { |
| pt_phdr_p = 1; |
| pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr, |
| 4, byte_order); |
| } |
| |
| if (p_type == type) |
| break; |
| } |
| |
| if (i == at_phnum) |
| return 0; |
| |
| /* Retrieve address and size. */ |
| sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, |
| 4, byte_order); |
| sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, |
| 4, byte_order); |
| } |
| else |
| { |
| Elf64_External_Phdr phdr; |
| int i; |
| |
| /* Search for requested PHDR. */ |
| for (i = 0; i < at_phnum; i++) |
| { |
| int p_type; |
| |
| if (target_read_memory (at_phdr + i * sizeof (phdr), |
| (gdb_byte *)&phdr, sizeof (phdr))) |
| return 0; |
| |
| p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, |
| 4, byte_order); |
| |
| if (p_type == PT_PHDR) |
| { |
| pt_phdr_p = 1; |
| pt_phdr = extract_unsigned_integer ((gdb_byte *) phdr.p_vaddr, |
| 8, byte_order); |
| } |
| |
| if (p_type == type) |
| break; |
| } |
| |
| if (i == at_phnum) |
| return 0; |
| |
| /* Retrieve address and size. */ |
| sect_addr = extract_unsigned_integer ((gdb_byte *)phdr.p_vaddr, |
| 8, byte_order); |
| sect_size = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, |
| 8, byte_order); |
| } |
| |
| /* PT_PHDR is optional, but we really need it |
| for PIE to make this work in general. */ |
| |
| if (pt_phdr_p) |
| { |
| /* at_phdr is real address in memory. pt_phdr is what pheader says it is. |
| Relocation offset is the difference between the two. */ |
| sect_addr = sect_addr + (at_phdr - pt_phdr); |
| } |
| |
| /* Read in requested program header. */ |
| buf = (gdb_byte *) xmalloc (sect_size); |
| if (target_read_memory (sect_addr, buf, sect_size)) |
| { |
| xfree (buf); |
| return NULL; |
| } |
| |
| if (p_arch_size) |
| *p_arch_size = arch_size; |
| if (p_sect_size) |
| *p_sect_size = sect_size; |
| if (base_addr) |
| *base_addr = sect_addr; |
| |
| return buf; |
| } |
| |
| |
| /* Return program interpreter string. */ |
| static char * |
| find_program_interpreter (void) |
| { |
| gdb_byte *buf = NULL; |
| |
| /* If we have an exec_bfd, use its section table. */ |
| if (exec_bfd |
| && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| { |
| struct bfd_section *interp_sect; |
| |
| interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); |
| if (interp_sect != NULL) |
| { |
| int sect_size = bfd_section_size (exec_bfd, interp_sect); |
| |
| buf = (gdb_byte *) xmalloc (sect_size); |
| bfd_get_section_contents (exec_bfd, interp_sect, buf, 0, sect_size); |
| } |
| } |
| |
| /* If we didn't find it, use the target auxillary vector. */ |
| if (!buf) |
| buf = read_program_header (PT_INTERP, NULL, NULL, NULL); |
| |
| return (char *) buf; |
| } |
| |
| |
| /* Scan for DESIRED_DYNTAG in .dynamic section of ABFD. If DESIRED_DYNTAG is |
| found, 1 is returned and the corresponding PTR is set. */ |
| |
| static int |
| scan_dyntag (const int desired_dyntag, bfd *abfd, CORE_ADDR *ptr, |
| CORE_ADDR *ptr_addr) |
| { |
| int arch_size, step, sect_size; |
| long current_dyntag; |
| CORE_ADDR dyn_ptr, dyn_addr; |
| gdb_byte *bufend, *bufstart, *buf; |
| Elf32_External_Dyn *x_dynp_32; |
| Elf64_External_Dyn *x_dynp_64; |
| struct bfd_section *sect; |
| struct target_section *target_section; |
| |
| if (abfd == NULL) |
| return 0; |
| |
| if (bfd_get_flavour (abfd) != bfd_target_elf_flavour) |
| return 0; |
| |
| arch_size = bfd_get_arch_size (abfd); |
| if (arch_size == -1) |
| return 0; |
| |
| /* Find the start address of the .dynamic section. */ |
| sect = bfd_get_section_by_name (abfd, ".dynamic"); |
| if (sect == NULL) |
| return 0; |
| |
| for (target_section = current_target_sections->sections; |
| target_section < current_target_sections->sections_end; |
| target_section++) |
| if (sect == target_section->the_bfd_section) |
| break; |
| if (target_section < current_target_sections->sections_end) |
| dyn_addr = target_section->addr; |
| else |
| { |
| /* ABFD may come from OBJFILE acting only as a symbol file without being |
| loaded into the target (see add_symbol_file_command). This case is |
| such fallback to the file VMA address without the possibility of |
| having the section relocated to its actual in-memory address. */ |
| |
| dyn_addr = bfd_section_vma (abfd, sect); |
| } |
| |
| /* Read in .dynamic from the BFD. We will get the actual value |
| from memory later. */ |
| sect_size = bfd_section_size (abfd, sect); |
| buf = bufstart = (gdb_byte *) alloca (sect_size); |
| if (!bfd_get_section_contents (abfd, sect, |
| buf, 0, sect_size)) |
| return 0; |
| |
| /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ |
| step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) |
| : sizeof (Elf64_External_Dyn); |
| for (bufend = buf + sect_size; |
| buf < bufend; |
| buf += step) |
| { |
| if (arch_size == 32) |
| { |
| x_dynp_32 = (Elf32_External_Dyn *) buf; |
| current_dyntag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag); |
| dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr); |
| } |
| else |
| { |
| x_dynp_64 = (Elf64_External_Dyn *) buf; |
| current_dyntag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag); |
| dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr); |
| } |
| if (current_dyntag == DT_NULL) |
| return 0; |
| if (current_dyntag == desired_dyntag) |
| { |
| /* If requested, try to read the runtime value of this .dynamic |
| entry. */ |
| if (ptr) |
| { |
| struct type *ptr_type; |
| gdb_byte ptr_buf[8]; |
| CORE_ADDR ptr_addr_1; |
| |
| ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| ptr_addr_1 = dyn_addr + (buf - bufstart) + arch_size / 8; |
| if (target_read_memory (ptr_addr_1, ptr_buf, arch_size / 8) == 0) |
| dyn_ptr = extract_typed_address (ptr_buf, ptr_type); |
| *ptr = dyn_ptr; |
| if (ptr_addr) |
| *ptr_addr = dyn_addr + (buf - bufstart); |
| } |
| return 1; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* Scan for DESIRED_DYNTAG in .dynamic section of the target's main executable, |
| found by consulting the OS auxillary vector. If DESIRED_DYNTAG is found, 1 |
| is returned and the corresponding PTR is set. */ |
| |
| static int |
| scan_dyntag_auxv (const int desired_dyntag, CORE_ADDR *ptr, |
| CORE_ADDR *ptr_addr) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| int sect_size, arch_size, step; |
| long current_dyntag; |
| CORE_ADDR dyn_ptr; |
| CORE_ADDR base_addr; |
| gdb_byte *bufend, *bufstart, *buf; |
| |
| /* Read in .dynamic section. */ |
| buf = bufstart = read_program_header (PT_DYNAMIC, §_size, &arch_size, |
| &base_addr); |
| if (!buf) |
| return 0; |
| |
| /* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */ |
| step = (arch_size == 32) ? sizeof (Elf32_External_Dyn) |
| : sizeof (Elf64_External_Dyn); |
| for (bufend = buf + sect_size; |
| buf < bufend; |
| buf += step) |
| { |
| if (arch_size == 32) |
| { |
| Elf32_External_Dyn *dynp = (Elf32_External_Dyn *) buf; |
| |
| current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, |
| 4, byte_order); |
| dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, |
| 4, byte_order); |
| } |
| else |
| { |
| Elf64_External_Dyn *dynp = (Elf64_External_Dyn *) buf; |
| |
| current_dyntag = extract_unsigned_integer ((gdb_byte *) dynp->d_tag, |
| 8, byte_order); |
| dyn_ptr = extract_unsigned_integer ((gdb_byte *) dynp->d_un.d_ptr, |
| 8, byte_order); |
| } |
| if (current_dyntag == DT_NULL) |
| break; |
| |
| if (current_dyntag == desired_dyntag) |
| { |
| if (ptr) |
| *ptr = dyn_ptr; |
| |
| if (ptr_addr) |
| *ptr_addr = base_addr + buf - bufstart; |
| |
| xfree (bufstart); |
| return 1; |
| } |
| } |
| |
| xfree (bufstart); |
| return 0; |
| } |
| |
| /* Locate the base address of dynamic linker structs for SVR4 elf |
| targets. |
| |
| For SVR4 elf targets the address of the dynamic linker's runtime |
| structure is contained within the dynamic info section in the |
| executable file. The dynamic section is also mapped into the |
| inferior address space. Because the runtime loader fills in the |
| real address before starting the inferior, we have to read in the |
| dynamic info section from the inferior address space. |
| If there are any errors while trying to find the address, we |
| silently return 0, otherwise the found address is returned. */ |
| |
| static CORE_ADDR |
| elf_locate_base (void) |
| { |
| struct bound_minimal_symbol msymbol; |
| CORE_ADDR dyn_ptr, dyn_ptr_addr; |
| |
| /* Look for DT_MIPS_RLD_MAP first. MIPS executables use this |
| instead of DT_DEBUG, although they sometimes contain an unused |
| DT_DEBUG. */ |
| if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr, NULL) |
| || scan_dyntag_auxv (DT_MIPS_RLD_MAP, &dyn_ptr, NULL)) |
| { |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| gdb_byte *pbuf; |
| int pbuf_size = TYPE_LENGTH (ptr_type); |
| |
| pbuf = (gdb_byte *) alloca (pbuf_size); |
| /* DT_MIPS_RLD_MAP contains a pointer to the address |
| of the dynamic link structure. */ |
| if (target_read_memory (dyn_ptr, pbuf, pbuf_size)) |
| return 0; |
| return extract_typed_address (pbuf, ptr_type); |
| } |
| |
| /* Then check DT_MIPS_RLD_MAP_REL. MIPS executables now use this form |
| because of needing to support PIE. DT_MIPS_RLD_MAP will also exist |
| in non-PIE. */ |
| if (scan_dyntag (DT_MIPS_RLD_MAP_REL, exec_bfd, &dyn_ptr, &dyn_ptr_addr) |
| || scan_dyntag_auxv (DT_MIPS_RLD_MAP_REL, &dyn_ptr, &dyn_ptr_addr)) |
| { |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| gdb_byte *pbuf; |
| int pbuf_size = TYPE_LENGTH (ptr_type); |
| |
| pbuf = (gdb_byte *) alloca (pbuf_size); |
| /* DT_MIPS_RLD_MAP_REL contains an offset from the address of the |
| DT slot to the address of the dynamic link structure. */ |
| if (target_read_memory (dyn_ptr + dyn_ptr_addr, pbuf, pbuf_size)) |
| return 0; |
| return extract_typed_address (pbuf, ptr_type); |
| } |
| |
| /* Find DT_DEBUG. */ |
| if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr, NULL) |
| || scan_dyntag_auxv (DT_DEBUG, &dyn_ptr, NULL)) |
| return dyn_ptr; |
| |
| /* This may be a static executable. Look for the symbol |
| conventionally named _r_debug, as a last resort. */ |
| msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile); |
| if (msymbol.minsym != NULL) |
| return BMSYMBOL_VALUE_ADDRESS (msymbol); |
| |
| /* DT_DEBUG entry not found. */ |
| return 0; |
| } |
| |
| /* Locate the base address of dynamic linker structs. |
| |
| For both the SunOS and SVR4 shared library implementations, if the |
| inferior executable has been linked dynamically, there is a single |
| address somewhere in the inferior's data space which is the key to |
| locating all of the dynamic linker's runtime structures. This |
| address is the value of the debug base symbol. The job of this |
| function is to find and return that address, or to return 0 if there |
| is no such address (the executable is statically linked for example). |
| |
| For SunOS, the job is almost trivial, since the dynamic linker and |
| all of it's structures are statically linked to the executable at |
| link time. Thus the symbol for the address we are looking for has |
| already been added to the minimal symbol table for the executable's |
| objfile at the time the symbol file's symbols were read, and all we |
| have to do is look it up there. Note that we explicitly do NOT want |
| to find the copies in the shared library. |
| |
| The SVR4 version is a bit more complicated because the address |
| is contained somewhere in the dynamic info section. We have to go |
| to a lot more work to discover the address of the debug base symbol. |
| Because of this complexity, we cache the value we find and return that |
| value on subsequent invocations. Note there is no copy in the |
| executable symbol tables. */ |
| |
| static CORE_ADDR |
| locate_base (struct svr4_info *info) |
| { |
| /* Check to see if we have a currently valid address, and if so, avoid |
| doing all this work again and just return the cached address. If |
| we have no cached address, try to locate it in the dynamic info |
| section for ELF executables. There's no point in doing any of this |
| though if we don't have some link map offsets to work with. */ |
| |
| if (info->debug_base == 0 && svr4_have_link_map_offsets ()) |
| info->debug_base = elf_locate_base (); |
| return info->debug_base; |
| } |
| |
| /* Find the first element in the inferior's dynamic link map, and |
| return its address in the inferior. Return zero if the address |
| could not be determined. |
| |
| FIXME: Perhaps we should validate the info somehow, perhaps by |
| checking r_version for a known version number, or r_state for |
| RT_CONSISTENT. */ |
| |
| static CORE_ADDR |
| solib_svr4_r_map (struct svr4_info *info) |
| { |
| struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| CORE_ADDR addr = 0; |
| |
| TRY |
| { |
| addr = read_memory_typed_address (info->debug_base + lmo->r_map_offset, |
| ptr_type); |
| } |
| CATCH (ex, RETURN_MASK_ERROR) |
| { |
| exception_print (gdb_stderr, ex); |
| } |
| END_CATCH |
| |
| return addr; |
| } |
| |
| /* Find r_brk from the inferior's debug base. */ |
| |
| static CORE_ADDR |
| solib_svr4_r_brk (struct svr4_info *info) |
| { |
| struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| |
| return read_memory_typed_address (info->debug_base + lmo->r_brk_offset, |
| ptr_type); |
| } |
| |
| /* Find the link map for the dynamic linker (if it is not in the |
| normal list of loaded shared objects). */ |
| |
| static CORE_ADDR |
| solib_svr4_r_ldsomap (struct svr4_info *info) |
| { |
| struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| ULONGEST version = 0; |
| |
| TRY |
| { |
| /* Check version, and return zero if `struct r_debug' doesn't have |
| the r_ldsomap member. */ |
| version |
| = read_memory_unsigned_integer (info->debug_base + lmo->r_version_offset, |
| lmo->r_version_size, byte_order); |
| } |
| CATCH (ex, RETURN_MASK_ERROR) |
| { |
| exception_print (gdb_stderr, ex); |
| } |
| END_CATCH |
| |
| if (version < 2 || lmo->r_ldsomap_offset == -1) |
| return 0; |
| |
| return read_memory_typed_address (info->debug_base + lmo->r_ldsomap_offset, |
| ptr_type); |
| } |
| |
| /* On Solaris systems with some versions of the dynamic linker, |
| ld.so's l_name pointer points to the SONAME in the string table |
| rather than into writable memory. So that GDB can find shared |
| libraries when loading a core file generated by gcore, ensure that |
| memory areas containing the l_name string are saved in the core |
| file. */ |
| |
| static int |
| svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size) |
| { |
| struct svr4_info *info; |
| CORE_ADDR ldsomap; |
| struct so_list *newobj; |
| struct cleanup *old_chain; |
| CORE_ADDR name_lm; |
| |
| info = get_svr4_info (); |
| |
| info->debug_base = 0; |
| locate_base (info); |
| if (!info->debug_base) |
| return 0; |
| |
| ldsomap = solib_svr4_r_ldsomap (info); |
| if (!ldsomap) |
| return 0; |
| |
| newobj = XCNEW (struct so_list); |
| old_chain = make_cleanup (xfree, newobj); |
| newobj->lm_info = lm_info_read (ldsomap); |
| make_cleanup (xfree, newobj->lm_info); |
| name_lm = newobj->lm_info ? newobj->lm_info->l_name : 0; |
| do_cleanups (old_chain); |
| |
| return (name_lm >= vaddr && name_lm < vaddr + size); |
| } |
| |
| /* Implement the "open_symbol_file_object" target_so_ops method. |
| |
| If no open symbol file, attempt to locate and open the main symbol |
| file. On SVR4 systems, this is the first link map entry. If its |
| name is here, we can open it. Useful when attaching to a process |
| without first loading its symbol file. */ |
| |
| static int |
| open_symbol_file_object (void *from_ttyp) |
| { |
| CORE_ADDR lm, l_name; |
| char *filename; |
| int errcode; |
| int from_tty = *(int *)from_ttyp; |
| struct link_map_offsets *lmo = svr4_fetch_link_map_offsets (); |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| int l_name_size = TYPE_LENGTH (ptr_type); |
| gdb_byte *l_name_buf = (gdb_byte *) xmalloc (l_name_size); |
| struct cleanup *cleanups = make_cleanup (xfree, l_name_buf); |
| struct svr4_info *info = get_svr4_info (); |
| symfile_add_flags add_flags = 0; |
| |
| if (from_tty) |
| add_flags |= SYMFILE_VERBOSE; |
| |
| if (symfile_objfile) |
| if (!query (_("Attempt to reload symbols from process? "))) |
| { |
| do_cleanups (cleanups); |
| return 0; |
| } |
| |
| /* Always locate the debug struct, in case it has moved. */ |
| info->debug_base = 0; |
| if (locate_base (info) == 0) |
| { |
| do_cleanups (cleanups); |
| return 0; /* failed somehow... */ |
| } |
| |
| /* First link map member should be the executable. */ |
| lm = solib_svr4_r_map (info); |
| if (lm == 0) |
| { |
| do_cleanups (cleanups); |
| return 0; /* failed somehow... */ |
| } |
| |
| /* Read address of name from target memory to GDB. */ |
| read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size); |
| |
| /* Convert the address to host format. */ |
| l_name = extract_typed_address (l_name_buf, ptr_type); |
| |
| if (l_name == 0) |
| { |
| do_cleanups (cleanups); |
| return 0; /* No filename. */ |
| } |
| |
| /* Now fetch the filename from target memory. */ |
| target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode); |
| make_cleanup (xfree, filename); |
| |
| if (errcode) |
| { |
| warning (_("failed to read exec filename from attached file: %s"), |
| safe_strerror (errcode)); |
| do_cleanups (cleanups); |
| return 0; |
| } |
| |
| /* Have a pathname: read the symbol file. */ |
| symbol_file_add_main (filename, add_flags); |
| |
| do_cleanups (cleanups); |
| return 1; |
| } |
| |
| /* Data exchange structure for the XML parser as returned by |
| svr4_current_sos_via_xfer_libraries. */ |
| |
| struct svr4_library_list |
| { |
| struct so_list *head, **tailp; |
| |
| /* Inferior address of struct link_map used for the main executable. It is |
| NULL if not known. */ |
| CORE_ADDR main_lm; |
| }; |
| |
| /* Implementation for target_so_ops.free_so. */ |
| |
| static void |
| svr4_free_so (struct so_list *so) |
| { |
| xfree (so->lm_info); |
| } |
| |
| /* Implement target_so_ops.clear_so. */ |
| |
| static void |
| svr4_clear_so (struct so_list *so) |
| { |
| if (so->lm_info != NULL) |
| so->lm_info->l_addr_p = 0; |
| } |
| |
| /* Free so_list built so far (called via cleanup). */ |
| |
| static void |
| svr4_free_library_list (void *p_list) |
| { |
| struct so_list *list = *(struct so_list **) p_list; |
| |
| while (list != NULL) |
| { |
| struct so_list *next = list->next; |
| |
| free_so (list); |
| list = next; |
| } |
| } |
| |
| /* Copy library list. */ |
| |
| static struct so_list * |
| svr4_copy_library_list (struct so_list *src) |
| { |
| struct so_list *dst = NULL; |
| struct so_list **link = &dst; |
| |
| while (src != NULL) |
| { |
| struct so_list *newobj; |
| |
| newobj = XNEW (struct so_list); |
| memcpy (newobj, src, sizeof (struct so_list)); |
| |
| newobj->lm_info = XNEW (struct lm_info); |
| memcpy (newobj->lm_info, src->lm_info, sizeof (struct lm_info)); |
| |
| newobj->next = NULL; |
| *link = newobj; |
| link = &newobj->next; |
| |
| src = src->next; |
| } |
| |
| return dst; |
| } |
| |
| #ifdef HAVE_LIBEXPAT |
| |
| #include "xml-support.h" |
| |
| /* Handle the start of a <library> element. Note: new elements are added |
| at the tail of the list, keeping the list in order. */ |
| |
| static void |
| library_list_start_library (struct gdb_xml_parser *parser, |
| const struct gdb_xml_element *element, |
| void *user_data, VEC(gdb_xml_value_s) *attributes) |
| { |
| struct svr4_library_list *list = (struct svr4_library_list *) user_data; |
| const char *name |
| = (const char *) xml_find_attribute (attributes, "name")->value; |
| ULONGEST *lmp |
| = (ULONGEST *) xml_find_attribute (attributes, "lm")->value; |
| ULONGEST *l_addrp |
| = (ULONGEST *) xml_find_attribute (attributes, "l_addr")->value; |
| ULONGEST *l_ldp |
| = (ULONGEST *) xml_find_attribute (attributes, "l_ld")->value; |
| struct so_list *new_elem; |
| |
| new_elem = XCNEW (struct so_list); |
| new_elem->lm_info = XCNEW (struct lm_info); |
| new_elem->lm_info->lm_addr = *lmp; |
| new_elem->lm_info->l_addr_inferior = *l_addrp; |
| new_elem->lm_info->l_ld = *l_ldp; |
| |
| strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1); |
| new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0; |
| strcpy (new_elem->so_original_name, new_elem->so_name); |
| |
| *list->tailp = new_elem; |
| list->tailp = &new_elem->next; |
| } |
| |
| /* Handle the start of a <library-list-svr4> element. */ |
| |
| static void |
| svr4_library_list_start_list (struct gdb_xml_parser *parser, |
| const struct gdb_xml_element *element, |
| void *user_data, VEC(gdb_xml_value_s) *attributes) |
| { |
| struct svr4_library_list *list = (struct svr4_library_list *) user_data; |
| const char *version |
| = (const char *) xml_find_attribute (attributes, "version")->value; |
| struct gdb_xml_value *main_lm = xml_find_attribute (attributes, "main-lm"); |
| |
| if (strcmp (version, "1.0") != 0) |
| gdb_xml_error (parser, |
| _("SVR4 Library list has unsupported version \"%s\""), |
| version); |
| |
| if (main_lm) |
| list->main_lm = *(ULONGEST *) main_lm->value; |
| } |
| |
| /* The allowed elements and attributes for an XML library list. |
| The root element is a <library-list>. */ |
| |
| static const struct gdb_xml_attribute svr4_library_attributes[] = |
| { |
| { "name", GDB_XML_AF_NONE, NULL, NULL }, |
| { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, |
| { NULL, GDB_XML_AF_NONE, NULL, NULL } |
| }; |
| |
| static const struct gdb_xml_element svr4_library_list_children[] = |
| { |
| { |
| "library", svr4_library_attributes, NULL, |
| GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL, |
| library_list_start_library, NULL |
| }, |
| { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } |
| }; |
| |
| static const struct gdb_xml_attribute svr4_library_list_attributes[] = |
| { |
| { "version", GDB_XML_AF_NONE, NULL, NULL }, |
| { "main-lm", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL }, |
| { NULL, GDB_XML_AF_NONE, NULL, NULL } |
| }; |
| |
| static const struct gdb_xml_element svr4_library_list_elements[] = |
| { |
| { "library-list-svr4", svr4_library_list_attributes, svr4_library_list_children, |
| GDB_XML_EF_NONE, svr4_library_list_start_list, NULL }, |
| { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } |
| }; |
| |
| /* Parse qXfer:libraries:read packet into *SO_LIST_RETURN. Return 1 if |
| |
| Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such |
| case. Return 1 if *SO_LIST_RETURN contains the library list, it may be |
| empty, caller is responsible for freeing all its entries. */ |
| |
| static int |
| svr4_parse_libraries (const char *document, struct svr4_library_list *list) |
| { |
| struct cleanup *back_to = make_cleanup (svr4_free_library_list, |
| &list->head); |
| |
| memset (list, 0, sizeof (*list)); |
| list->tailp = &list->head; |
| if (gdb_xml_parse_quick (_("target library list"), "library-list-svr4.dtd", |
| svr4_library_list_elements, document, list) == 0) |
| { |
| /* Parsed successfully, keep the result. */ |
| discard_cleanups (back_to); |
| return 1; |
| } |
| |
| do_cleanups (back_to); |
| return 0; |
| } |
| |
| /* Attempt to get so_list from target via qXfer:libraries-svr4:read packet. |
| |
| Return 0 if packet not supported, *SO_LIST_RETURN is not modified in such |
| case. Return 1 if *SO_LIST_RETURN contains the library list, it may be |
| empty, caller is responsible for freeing all its entries. |
| |
| Note that ANNEX must be NULL if the remote does not explicitly allow |
| qXfer:libraries-svr4:read packets with non-empty annexes. Support for |
| this can be checked using target_augmented_libraries_svr4_read (). */ |
| |
| static int |
| svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list, |
| const char *annex) |
| { |
| char *svr4_library_document; |
| int result; |
| struct cleanup *back_to; |
| |
| gdb_assert (annex == NULL || target_augmented_libraries_svr4_read ()); |
| |
| /* Fetch the list of shared libraries. */ |
| svr4_library_document = target_read_stralloc (¤t_target, |
| TARGET_OBJECT_LIBRARIES_SVR4, |
| annex); |
| if (svr4_library_document == NULL) |
| return 0; |
| |
| back_to = make_cleanup (xfree, svr4_library_document); |
| result = svr4_parse_libraries (svr4_library_document, list); |
| do_cleanups (back_to); |
| |
| return result; |
| } |
| |
| #else |
| |
| static int |
| svr4_current_sos_via_xfer_libraries (struct svr4_library_list *list, |
| const char *annex) |
| { |
| return 0; |
| } |
| |
| #endif |
| |
| /* If no shared library information is available from the dynamic |
| linker, build a fallback list from other sources. */ |
| |
| static struct so_list * |
| svr4_default_sos (void) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| struct so_list *newobj; |
| |
| if (!info->debug_loader_offset_p) |
| return NULL; |
| |
| newobj = XCNEW (struct so_list); |
| |
| newobj->lm_info = XCNEW (struct lm_info); |
| |
| /* Nothing will ever check the other fields if we set l_addr_p. */ |
| newobj->lm_info->l_addr = info->debug_loader_offset; |
| newobj->lm_info->l_addr_p = 1; |
| |
| strncpy (newobj->so_name, info->debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1); |
| newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| strcpy (newobj->so_original_name, newobj->so_name); |
| |
| return newobj; |
| } |
| |
| /* Read the whole inferior libraries chain starting at address LM. |
| Expect the first entry in the chain's previous entry to be PREV_LM. |
| Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the |
| first entry if IGNORE_FIRST and set global MAIN_LM_ADDR according |
| to it. Returns nonzero upon success. If zero is returned the |
| entries stored to LINK_PTR_PTR are still valid although they may |
| represent only part of the inferior library list. */ |
| |
| static int |
| svr4_read_so_list (CORE_ADDR lm, CORE_ADDR prev_lm, |
| struct so_list ***link_ptr_ptr, int ignore_first) |
| { |
| CORE_ADDR first_l_name = 0; |
| CORE_ADDR next_lm; |
| |
| for (; lm != 0; prev_lm = lm, lm = next_lm) |
| { |
| struct so_list *newobj; |
| struct cleanup *old_chain; |
| int errcode; |
| char *buffer; |
| |
| newobj = XCNEW (struct so_list); |
| old_chain = make_cleanup_free_so (newobj); |
| |
| newobj->lm_info = lm_info_read (lm); |
| if (newobj->lm_info == NULL) |
| { |
| do_cleanups (old_chain); |
| return 0; |
| } |
| |
| next_lm = newobj->lm_info->l_next; |
| |
| if (newobj->lm_info->l_prev != prev_lm) |
| { |
| warning (_("Corrupted shared library list: %s != %s"), |
| paddress (target_gdbarch (), prev_lm), |
| paddress (target_gdbarch (), newobj->lm_info->l_prev)); |
| do_cleanups (old_chain); |
| return 0; |
| } |
| |
| /* For SVR4 versions, the first entry in the link map is for the |
| inferior executable, so we must ignore it. For some versions of |
| SVR4, it has no name. For others (Solaris 2.3 for example), it |
| does have a name, so we can no longer use a missing name to |
| decide when to ignore it. */ |
| if (ignore_first && newobj->lm_info->l_prev == 0) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| |
| first_l_name = newobj->lm_info->l_name; |
| info->main_lm_addr = newobj->lm_info->lm_addr; |
| do_cleanups (old_chain); |
| continue; |
| } |
| |
| /* Extract this shared object's name. */ |
| target_read_string (newobj->lm_info->l_name, &buffer, |
| SO_NAME_MAX_PATH_SIZE - 1, &errcode); |
| if (errcode != 0) |
| { |
| /* If this entry's l_name address matches that of the |
| inferior executable, then this is not a normal shared |
| object, but (most likely) a vDSO. In this case, silently |
| skip it; otherwise emit a warning. */ |
| if (first_l_name == 0 || newobj->lm_info->l_name != first_l_name) |
| warning (_("Can't read pathname for load map: %s."), |
| safe_strerror (errcode)); |
| do_cleanups (old_chain); |
| continue; |
| } |
| |
| strncpy (newobj->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1); |
| newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| strcpy (newobj->so_original_name, newobj->so_name); |
| xfree (buffer); |
| |
| /* If this entry has no name, or its name matches the name |
| for the main executable, don't include it in the list. */ |
| if (! newobj->so_name[0] || match_main (newobj->so_name)) |
| { |
| do_cleanups (old_chain); |
| continue; |
| } |
| |
| discard_cleanups (old_chain); |
| newobj->next = 0; |
| **link_ptr_ptr = newobj; |
| *link_ptr_ptr = &newobj->next; |
| } |
| |
| return 1; |
| } |
| |
| /* Read the full list of currently loaded shared objects directly |
| from the inferior, without referring to any libraries read and |
| stored by the probes interface. Handle special cases relating |
| to the first elements of the list. */ |
| |
| static struct so_list * |
| svr4_current_sos_direct (struct svr4_info *info) |
| { |
| CORE_ADDR lm; |
| struct so_list *head = NULL; |
| struct so_list **link_ptr = &head; |
| struct cleanup *back_to; |
| int ignore_first; |
| struct svr4_library_list library_list; |
| |
| /* Fall back to manual examination of the target if the packet is not |
| supported or gdbserver failed to find DT_DEBUG. gdb.server/solib-list.exp |
| tests a case where gdbserver cannot find the shared libraries list while |
| GDB itself is able to find it via SYMFILE_OBJFILE. |
| |
| Unfortunately statically linked inferiors will also fall back through this |
| suboptimal code path. */ |
| |
| info->using_xfer = svr4_current_sos_via_xfer_libraries (&library_list, |
| NULL); |
| if (info->using_xfer) |
| { |
| if (library_list.main_lm) |
| info->main_lm_addr = library_list.main_lm; |
| |
| return library_list.head ? library_list.head : svr4_default_sos (); |
| } |
| |
| /* Always locate the debug struct, in case it has moved. */ |
| info->debug_base = 0; |
| locate_base (info); |
| |
| /* If we can't find the dynamic linker's base structure, this |
| must not be a dynamically linked executable. Hmm. */ |
| if (! info->debug_base) |
| return svr4_default_sos (); |
| |
| /* Assume that everything is a library if the dynamic loader was loaded |
| late by a static executable. */ |
| if (exec_bfd && bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL) |
| ignore_first = 0; |
| else |
| ignore_first = 1; |
| |
| back_to = make_cleanup (svr4_free_library_list, &head); |
| |
| /* Walk the inferior's link map list, and build our list of |
| `struct so_list' nodes. */ |
| lm = solib_svr4_r_map (info); |
| if (lm) |
| svr4_read_so_list (lm, 0, &link_ptr, ignore_first); |
| |
| /* On Solaris, the dynamic linker is not in the normal list of |
| shared objects, so make sure we pick it up too. Having |
| symbol information for the dynamic linker is quite crucial |
| for skipping dynamic linker resolver code. */ |
| lm = solib_svr4_r_ldsomap (info); |
| if (lm) |
| svr4_read_so_list (lm, 0, &link_ptr, 0); |
| |
| discard_cleanups (back_to); |
| |
| if (head == NULL) |
| return svr4_default_sos (); |
| |
| return head; |
| } |
| |
| /* Implement the main part of the "current_sos" target_so_ops |
| method. */ |
| |
| static struct so_list * |
| svr4_current_sos_1 (void) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| |
| /* If the solib list has been read and stored by the probes |
| interface then we return a copy of the stored list. */ |
| if (info->solib_list != NULL) |
| return svr4_copy_library_list (info->solib_list); |
| |
| /* Otherwise obtain the solib list directly from the inferior. */ |
| return svr4_current_sos_direct (info); |
| } |
| |
| /* Implement the "current_sos" target_so_ops method. */ |
| |
| static struct so_list * |
| svr4_current_sos (void) |
| { |
| struct so_list *so_head = svr4_current_sos_1 (); |
| struct mem_range vsyscall_range; |
| |
| /* Filter out the vDSO module, if present. Its symbol file would |
| not be found on disk. The vDSO/vsyscall's OBJFILE is instead |
| managed by symfile-mem.c:add_vsyscall_page. */ |
| if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range) |
| && vsyscall_range.length != 0) |
| { |
| struct so_list **sop; |
| |
| sop = &so_head; |
| while (*sop != NULL) |
| { |
| struct so_list *so = *sop; |
| |
| /* We can't simply match the vDSO by starting address alone, |
| because lm_info->l_addr_inferior (and also l_addr) do not |
| necessarily represent the real starting address of the |
| ELF if the vDSO's ELF itself is "prelinked". The l_ld |
| field (the ".dynamic" section of the shared object) |
| always points at the absolute/resolved address though. |
| So check whether that address is inside the vDSO's |
| mapping instead. |
| |
| E.g., on Linux 3.16 (x86_64) the vDSO is a regular |
| 0-based ELF, and we see: |
| |
| (gdb) info auxv |
| 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffb000 |
| (gdb) p/x *_r_debug.r_map.l_next |
| $1 = {l_addr = 0x7ffff7ffb000, ..., l_ld = 0x7ffff7ffb318, ...} |
| |
| And on Linux 2.6.32 (x86_64) we see: |
| |
| (gdb) info auxv |
| 33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7ffff7ffe000 |
| (gdb) p/x *_r_debug.r_map.l_next |
| $5 = {l_addr = 0x7ffff88fe000, ..., l_ld = 0x7ffff7ffe580, ... } |
| |
| Dumping that vDSO shows: |
| |
| (gdb) info proc mappings |
| 0x7ffff7ffe000 0x7ffff7fff000 0x1000 0 [vdso] |
| (gdb) dump memory vdso.bin 0x7ffff7ffe000 0x7ffff7fff000 |
| # readelf -Wa vdso.bin |
| [...] |
| Entry point address: 0xffffffffff700700 |
| [...] |
| Section Headers: |
| [Nr] Name Type Address Off Size |
| [ 0] NULL 0000000000000000 000000 000000 |
| [ 1] .hash HASH ffffffffff700120 000120 000038 |
| [ 2] .dynsym DYNSYM ffffffffff700158 000158 0000d8 |
| [...] |
| [ 9] .dynamic DYNAMIC ffffffffff700580 000580 0000f0 |
| */ |
| if (address_in_mem_range (so->lm_info->l_ld, &vsyscall_range)) |
| { |
| *sop = so->next; |
| free_so (so); |
| break; |
| } |
| |
| sop = &so->next; |
| } |
| } |
| |
| return so_head; |
| } |
| |
| /* Get the address of the link_map for a given OBJFILE. */ |
| |
| CORE_ADDR |
| svr4_fetch_objfile_link_map (struct objfile *objfile) |
| { |
| struct so_list *so; |
| struct svr4_info *info = get_svr4_info (); |
| |
| /* Cause svr4_current_sos() to be run if it hasn't been already. */ |
| if (info->main_lm_addr == 0) |
| solib_add (NULL, 0, ¤t_target, auto_solib_add); |
| |
| /* svr4_current_sos() will set main_lm_addr for the main executable. */ |
| if (objfile == symfile_objfile) |
| return info->main_lm_addr; |
| |
| /* The other link map addresses may be found by examining the list |
| of shared libraries. */ |
| for (so = master_so_list (); so; so = so->next) |
| if (so->objfile == objfile) |
| return so->lm_info->lm_addr; |
| |
| /* Not found! */ |
| return 0; |
| } |
| |
| /* On some systems, the only way to recognize the link map entry for |
| the main executable file is by looking at its name. Return |
| non-zero iff SONAME matches one of the known main executable names. */ |
| |
| static int |
| match_main (const char *soname) |
| { |
| const char * const *mainp; |
| |
| for (mainp = main_name_list; *mainp != NULL; mainp++) |
| { |
| if (strcmp (soname, *mainp) == 0) |
| return (1); |
| } |
| |
| return (0); |
| } |
| |
| /* Return 1 if PC lies in the dynamic symbol resolution code of the |
| SVR4 run time loader. */ |
| |
| int |
| svr4_in_dynsym_resolve_code (CORE_ADDR pc) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| |
| return ((pc >= info->interp_text_sect_low |
| && pc < info->interp_text_sect_high) |
| || (pc >= info->interp_plt_sect_low |
| && pc < info->interp_plt_sect_high) |
| || in_plt_section (pc) |
| || in_gnu_ifunc_stub (pc)); |
| } |
| |
| /* Given an executable's ABFD and target, compute the entry-point |
| address. */ |
| |
| static CORE_ADDR |
| exec_entry_point (struct bfd *abfd, struct target_ops *targ) |
| { |
| CORE_ADDR addr; |
| |
| /* KevinB wrote ... for most targets, the address returned by |
| bfd_get_start_address() is the entry point for the start |
| function. But, for some targets, bfd_get_start_address() returns |
| the address of a function descriptor from which the entry point |
| address may be extracted. This address is extracted by |
| gdbarch_convert_from_func_ptr_addr(). The method |
| gdbarch_convert_from_func_ptr_addr() is the merely the identify |
| function for targets which don't use function descriptors. */ |
| addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| bfd_get_start_address (abfd), |
| targ); |
| return gdbarch_addr_bits_remove (target_gdbarch (), addr); |
| } |
| |
| /* A probe and its associated action. */ |
| |
| struct probe_and_action |
| { |
| /* The probe. */ |
| struct probe *probe; |
| |
| /* The relocated address of the probe. */ |
| CORE_ADDR address; |
| |
| /* The action. */ |
| enum probe_action action; |
| }; |
| |
| /* Returns a hash code for the probe_and_action referenced by p. */ |
| |
| static hashval_t |
| hash_probe_and_action (const void *p) |
| { |
| const struct probe_and_action *pa = (const struct probe_and_action *) p; |
| |
| return (hashval_t) pa->address; |
| } |
| |
| /* Returns non-zero if the probe_and_actions referenced by p1 and p2 |
| are equal. */ |
| |
| static int |
| equal_probe_and_action (const void *p1, const void *p2) |
| { |
| const struct probe_and_action *pa1 = (const struct probe_and_action *) p1; |
| const struct probe_and_action *pa2 = (const struct probe_and_action *) p2; |
| |
| return pa1->address == pa2->address; |
| } |
| |
| /* Register a solib event probe and its associated action in the |
| probes table. */ |
| |
| static void |
| register_solib_event_probe (struct probe *probe, CORE_ADDR address, |
| enum probe_action action) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| struct probe_and_action lookup, *pa; |
| void **slot; |
| |
| /* Create the probes table, if necessary. */ |
| if (info->probes_table == NULL) |
| info->probes_table = htab_create_alloc (1, hash_probe_and_action, |
| equal_probe_and_action, |
| xfree, xcalloc, xfree); |
| |
| lookup.probe = probe; |
| lookup.address = address; |
| slot = htab_find_slot (info->probes_table, &lookup, INSERT); |
| gdb_assert (*slot == HTAB_EMPTY_ENTRY); |
| |
| pa = XCNEW (struct probe_and_action); |
| pa->probe = probe; |
| pa->address = address; |
| pa->action = action; |
| |
| *slot = pa; |
| } |
| |
| /* Get the solib event probe at the specified location, and the |
| action associated with it. Returns NULL if no solib event probe |
| was found. */ |
| |
| static struct probe_and_action * |
| solib_event_probe_at (struct svr4_info *info, CORE_ADDR address) |
| { |
| struct probe_and_action lookup; |
| void **slot; |
| |
| lookup.address = address; |
| slot = htab_find_slot (info->probes_table, &lookup, NO_INSERT); |
| |
| if (slot == NULL) |
| return NULL; |
| |
| return (struct probe_and_action *) *slot; |
| } |
| |
| /* Decide what action to take when the specified solib event probe is |
| hit. */ |
| |
| static enum probe_action |
| solib_event_probe_action (struct probe_and_action *pa) |
| { |
| enum probe_action action; |
| unsigned probe_argc = 0; |
| struct frame_info *frame = get_current_frame (); |
| |
| action = pa->action; |
| if (action == DO_NOTHING || action == PROBES_INTERFACE_FAILED) |
| return action; |
| |
| gdb_assert (action == FULL_RELOAD || action == UPDATE_OR_RELOAD); |
| |
| /* Check that an appropriate number of arguments has been supplied. |
| We expect: |
| arg0: Lmid_t lmid (mandatory) |
| arg1: struct r_debug *debug_base (mandatory) |
| arg2: struct link_map *new (optional, for incremental updates) */ |
| TRY |
| { |
| probe_argc = get_probe_argument_count (pa->probe, frame); |
| } |
| CATCH (ex, RETURN_MASK_ERROR) |
| { |
| exception_print (gdb_stderr, ex); |
| probe_argc = 0; |
| } |
| END_CATCH |
| |
| /* If get_probe_argument_count throws an exception, probe_argc will |
| be set to zero. However, if pa->probe does not have arguments, |
| then get_probe_argument_count will succeed but probe_argc will |
| also be zero. Both cases happen because of different things, but |
| they are treated equally here: action will be set to |
| PROBES_INTERFACE_FAILED. */ |
| if (probe_argc == 2) |
| action = FULL_RELOAD; |
| else if (probe_argc < 2) |
| action = PROBES_INTERFACE_FAILED; |
| |
| return action; |
| } |
| |
| /* Populate the shared object list by reading the entire list of |
| shared objects from the inferior. Handle special cases relating |
| to the first elements of the list. Returns nonzero on success. */ |
| |
| static int |
| solist_update_full (struct svr4_info *info) |
| { |
| free_solib_list (info); |
| info->solib_list = svr4_current_sos_direct (info); |
| |
| return 1; |
| } |
| |
| /* Update the shared object list starting from the link-map entry |
| passed by the linker in the probe's third argument. Returns |
| nonzero if the list was successfully updated, or zero to indicate |
| failure. */ |
| |
| static int |
| solist_update_incremental (struct svr4_info *info, CORE_ADDR lm) |
| { |
| struct so_list *tail; |
| CORE_ADDR prev_lm; |
| |
| /* svr4_current_sos_direct contains logic to handle a number of |
| special cases relating to the first elements of the list. To |
| avoid duplicating this logic we defer to solist_update_full |
| if the list is empty. */ |
| if (info->solib_list == NULL) |
| return 0; |
| |
| /* Fall back to a full update if we are using a remote target |
| that does not support incremental transfers. */ |
| if (info->using_xfer && !target_augmented_libraries_svr4_read ()) |
| return 0; |
| |
| /* Walk to the end of the list. */ |
| for (tail = info->solib_list; tail->next != NULL; tail = tail->next) |
| /* Nothing. */; |
| prev_lm = tail->lm_info->lm_addr; |
| |
| /* Read the new objects. */ |
| if (info->using_xfer) |
| { |
| struct svr4_library_list library_list; |
| char annex[64]; |
| |
| xsnprintf (annex, sizeof (annex), "start=%s;prev=%s", |
| phex_nz (lm, sizeof (lm)), |
| phex_nz (prev_lm, sizeof (prev_lm))); |
| if (!svr4_current_sos_via_xfer_libraries (&library_list, annex)) |
| return 0; |
| |
| tail->next = library_list.head; |
| } |
| else |
| { |
| struct so_list **link = &tail->next; |
| |
| /* IGNORE_FIRST may safely be set to zero here because the |
| above check and deferral to solist_update_full ensures |
| that this call to svr4_read_so_list will never see the |
| first element. */ |
| if (!svr4_read_so_list (lm, prev_lm, &link, 0)) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* Disable the probes-based linker interface and revert to the |
| original interface. We don't reset the breakpoints as the |
| ones set up for the probes-based interface are adequate. */ |
| |
| static void |
| disable_probes_interface_cleanup (void *arg) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| |
| warning (_("Probes-based dynamic linker interface failed.\n" |
| "Reverting to original interface.\n")); |
| |
| free_probes_table (info); |
| free_solib_list (info); |
| } |
| |
| /* Update the solib list as appropriate when using the |
| probes-based linker interface. Do nothing if using the |
| standard interface. */ |
| |
| static void |
| svr4_handle_solib_event (void) |
| { |
| struct svr4_info *info = get_svr4_info (); |
| struct probe_and_action *pa; |
| enum probe_action action; |
| struct cleanup *old_chain, *usm_chain; |
| struct value *val = NULL; |
| CORE_ADDR pc, debug_base, lm = 0; |
| struct frame_info *frame = get_current_frame (); |
| |
| /* Do nothing if not using the probes interface. */ |
| if (info->probes_table == NULL) |
| return; |
| |
| /* If anything goes wrong we revert to the original linker |
| interface. */ |
| old_chain = make_cleanup (disable_probes_interface_cleanup, NULL); |
| |
| pc = regcache_read_pc (get_current_regcache ()); |
| pa = solib_event_probe_at (info, pc); |
| if (pa == NULL) |
| { |
| do_cleanups (old_chain); |
| return; |
| } |
| |
| action = solib_event_probe_action (pa); |
| if (action == PROBES_INTERFACE_FAILED) |
| { |
| do_cleanups (old_chain); |
| return; |
| } |
| |
| if (action == DO_NOTHING) |
| { |
| discard_cleanups (old_chain); |
| return; |
| } |
| |
| /* evaluate_probe_argument looks up symbols in the dynamic linker |
| using find_pc_section. find_pc_section is accelerated by a cache |
| called the section map. The section map is invalidated every |
| time a shared library is loaded or unloaded, and if the inferior |
| is generating a lot of shared library events then the section map |
| will be updated every time svr4_handle_solib_event is called. |
| We called find_pc_section in svr4_create_solib_event_breakpoints, |
| so we can guarantee that the dynamic linker's sections are in the |
| section map. We can therefore inhibit section map updates across |
| these calls to evaluate_probe_argument and save a lot of time. */ |
| inhibit_section_map_updates (current_program_space); |
| usm_chain = make_cleanup (resume_section_map_updates_cleanup, |
| current_program_space); |
| |
| TRY |
| { |
| val = evaluate_probe_argument (pa->probe, 1, frame); |
| } |
| CATCH (ex, RETURN_MASK_ERROR) |
| { |
| exception_print (gdb_stderr, ex); |
| val = NULL; |
| } |
| END_CATCH |
| |
| if (val == NULL) |
| { |
| do_cleanups (old_chain); |
| return; |
| } |
| |
| debug_base = value_as_address (val); |
| if (debug_base == 0) |
| { |
| do_cleanups (old_chain); |
| return; |
| } |
| |
| /* Always locate the debug struct, in case it moved. */ |
| info->debug_base = 0; |
| if (locate_base (info) == 0) |
| { |
| do_cleanups (old_chain); |
| return; |
| } |
| |
| /* GDB does not currently support libraries loaded via dlmopen |
| into namespaces other than the initial one. We must ignore |
| any namespace other than the initial namespace here until |
| support for this is added to GDB. */ |
| if (debug_base != info->debug_base) |
| action = DO_NOTHING; |
| |
| if (action == UPDATE_OR_RELOAD) |
| { |
| TRY |
| { |
| val = evaluate_probe_argument (pa->probe, 2, frame); |
| } |
| CATCH (ex, RETURN_MASK_ERROR) |
| { |
| exception_print (gdb_stderr, ex); |
| do_cleanups (old_chain); |
| return; |
| } |
| END_CATCH |
| |
| if (val != NULL) |
| lm = value_as_address (val); |
| |
| if (lm == 0) |
| action = FULL_RELOAD; |
| } |
| |
| /* Resume section map updates. */ |
| do_cleanups (usm_chain); |
| |
| if (action == UPDATE_OR_RELOAD) |
| { |
| if (!solist_update_incremental (info, lm)) |
| action = FULL_RELOAD; |
| } |
| |
| if (action == FULL_RELOAD) |
| { |
| if (!solist_update_full (info)) |
| { |
| do_cleanups (old_chain); |
| return; |
| } |
| } |
| |
| discard_cleanups (old_chain); |
| } |
| |
| /* Helper function for svr4_update_solib_event_breakpoints. */ |
| |
| static int |
| svr4_update_solib_event_breakpoint (struct breakpoint *b, void *arg) |
| { |
| struct bp_location *loc; |
| |
| if (b->type != bp_shlib_event) |
| { |
| /* Continue iterating. */ |
| return 0; |
| } |
| |
| for (loc = b->loc; loc != NULL; loc = loc->next) |
| { |
| struct svr4_info *info; |
| struct probe_and_action *pa; |
| |
| info = ((struct svr4_info *) |
| program_space_data (loc->pspace, solib_svr4_pspace_data)); |
| if (info == NULL || info->probes_table == NULL) |
| continue; |
| |
| pa = solib_event_probe_at (info, loc->address); |
| if (pa == NULL) |
| continue; |
| |
| if (pa->action == DO_NOTHING) |
| { |
| if (b->enable_state == bp_disabled && stop_on_solib_events) |
| enable_breakpoint (b); |
| else if (b->enable_state == bp_enabled && !stop_on_solib_events) |
| disable_breakpoint (b); |
| } |
| |
| break; |
| } |
| |
| /* Continue iterating. */ |
| return 0; |
| } |
| |
| /* Enable or disable optional solib event breakpoints as appropriate. |
| Called whenever stop_on_solib_events is changed. */ |
| |
| static void |
| svr4_update_solib_event_breakpoints (void) |
| { |
| iterate_over_breakpoints (svr4_update_solib_event_breakpoint, NULL); |
| } |
| |
| /* Create and register solib event breakpoints. PROBES is an array |
| of NUM_PROBES elements, each of which is vector of probes. A |
| solib event breakpoint will be created and registered for each |
| probe. */ |
| |
| static void |
| svr4_create_probe_breakpoints (struct gdbarch *gdbarch, |
| VEC (probe_p) **probes, |
| struct objfile *objfile) |
| { |
| int i; |
| |
| for (i = 0; i < NUM_PROBES; i++) |
| { |
| enum probe_action action = probe_info[i].action; |
| struct probe *probe; |
| int ix; |
| |
| for (ix = 0; |
| VEC_iterate (probe_p, probes[i], ix, probe); |
| ++ix) |
| { |
| CORE_ADDR address = get_probe_address (probe, objfile); |
| |
| create_solib_event_breakpoint (gdbarch, address); |
| register_solib_event_probe (probe, address, action); |
| } |
| } |
| |
| svr4_update_solib_event_breakpoints (); |
| } |
| |
| /* Both the SunOS and the SVR4 dynamic linkers call a marker function |
| before and after mapping and unmapping shared libraries. The sole |
| purpose of this method is to allow debuggers to set a breakpoint so |
| they can track these changes. |
| |
| Some versions of the glibc dynamic linker contain named probes |
| to allow more fine grained stopping. Given the address of the |
| original marker function, this function attempts to find these |
| probes, and if found, sets breakpoints on those instead. If the |
| probes aren't found, a single breakpoint is set on the original |
| marker function. */ |
| |
| static void |
| svr4_create_solib_event_breakpoints (struct gdbarch *gdbarch, |
| CORE_ADDR address) |
| { |
| struct obj_section *os; |
| |
| os = find_pc_section (address); |
| if (os != NULL) |
| { |
| int with_prefix; |
| |
| for (with_prefix = 0; with_prefix <= 1; with_prefix++) |
| { |
| VEC (probe_p) *probes[NUM_PROBES]; |
| int all_probes_found = 1; |
| int checked_can_use_probe_arguments = 0; |
| int i; |
| |
| memset (probes, 0, sizeof (probes)); |
| for (i = 0; i < NUM_PROBES; i++) |
| { |
| const char *name = probe_info[i].name; |
| struct probe *p; |
| char buf[32]; |
| |
| /* Fedora 17 and Red Hat Enterprise Linux 6.2-6.4 |
| shipped with an early version of the probes code in |
| which the probes' names were prefixed with "rtld_" |
| and the "map_failed" probe did not exist. The |
| locations of the probes are otherwise the same, so |
| we check for probes with prefixed names if probes |
| with unprefixed names are not present. */ |
| if (with_prefix) |
| { |
| xsnprintf (buf, sizeof (buf), "rtld_%s", name); |
| name = buf; |
| } |
| |
| probes[i] = find_probes_in_objfile (os->objfile, "rtld", name); |
| |
| /* The "map_failed" probe did not exist in early |
| versions of the probes code in which the probes' |
| names were prefixed with "rtld_". */ |
| if (strcmp (name, "rtld_map_failed") == 0) |
| continue; |
| |
| if (VEC_empty (probe_p, probes[i])) |
| { |
| all_probes_found = 0; |
| break; |
| } |
| |
| /* Ensure probe arguments can be evaluated. */ |
| if (!checked_can_use_probe_arguments) |
| { |
| p = VEC_index (probe_p, probes[i], 0); |
| if (!can_evaluate_probe_arguments (p)) |
| { |
| all_probes_found = 0; |
| break; |
| } |
| checked_can_use_probe_arguments = 1; |
| } |
| } |
| |
| if (all_probes_found) |
| svr4_create_probe_breakpoints (gdbarch, probes, os->objfile); |
| |
| for (i = 0; i < NUM_PROBES; i++) |
| VEC_free (probe_p, probes[i]); |
| |
| if (all_probes_found) |
| return; |
| } |
| } |
| |
| create_solib_event_breakpoint (gdbarch, address); |
| } |
| |
| /* Helper function for gdb_bfd_lookup_symbol. */ |
| |
| static int |
| cmp_name_and_sec_flags (const asymbol *sym, const void *data) |
| { |
| return (strcmp (sym->name, (const char *) data) == 0 |
| && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0); |
| } |
| /* Arrange for dynamic linker to hit breakpoint. |
| |
| Both the SunOS and the SVR4 dynamic linkers have, as part of their |
| debugger interface, support for arranging for the inferior to hit |
| a breakpoint after mapping in the shared libraries. This function |
| enables that breakpoint. |
| |
| For SunOS, there is a special flag location (in_debugger) which we |
| set to 1. When the dynamic linker sees this flag set, it will set |
| a breakpoint at a location known only to itself, after saving the |
| original contents of that place and the breakpoint address itself, |
| in it's own internal structures. When we resume the inferior, it |
| will eventually take a SIGTRAP when it runs into the breakpoint. |
| We handle this (in a different place) by restoring the contents of |
| the breakpointed location (which is only known after it stops), |
| chasing around to locate the shared libraries that have been |
| loaded, then resuming. |
| |
| For SVR4, the debugger interface structure contains a member (r_brk) |
| which is statically initialized at the time the shared library is |
| built, to the offset of a function (_r_debug_state) which is guaran- |
| teed to be called once before mapping in a library, and again when |
| the mapping is complete. At the time we are examining this member, |
| it contains only the unrelocated offset of the function, so we have |
| to do our own relocation. Later, when the dynamic linker actually |
| runs, it relocates r_brk to be the actual address of _r_debug_state(). |
| |
| The debugger interface structure also contains an enumeration which |
| is set to either RT_ADD or RT_DELETE prior to changing the mapping, |
| depending upon whether or not the library is being mapped or unmapped, |
| and then set to RT_CONSISTENT after the library is mapped/unmapped. */ |
| |
| static int |
| enable_break (struct svr4_info *info, int from_tty) |
| { |
| struct bound_minimal_symbol msymbol; |
| const char * const *bkpt_namep; |
| asection *interp_sect; |
| char *interp_name; |
| CORE_ADDR sym_addr; |
| |
| info->interp_text_sect_low = info->interp_text_sect_high = 0; |
| info->interp_plt_sect_low = info->interp_plt_sect_high = 0; |
| |
| /* If we already have a shared library list in the target, and |
| r_debug contains r_brk, set the breakpoint there - this should |
| mean r_brk has already been relocated. Assume the dynamic linker |
| is the object containing r_brk. */ |
| |
| solib_add (NULL, from_tty, ¤t_target, auto_solib_add); |
| sym_addr = 0; |
| if (info->debug_base && solib_svr4_r_map (info) != 0) |
| sym_addr = solib_svr4_r_brk (info); |
| |
| if (sym_addr != 0) |
| { |
| struct obj_section *os; |
| |
| sym_addr = gdbarch_addr_bits_remove |
| (target_gdbarch (), gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| sym_addr, |
| ¤t_target)); |
| |
| /* On at least some versions of Solaris there's a dynamic relocation |
| on _r_debug.r_brk and SYM_ADDR may not be relocated yet, e.g., if |
| we get control before the dynamic linker has self-relocated. |
| Check if SYM_ADDR is in a known section, if it is assume we can |
| trust its value. This is just a heuristic though, it could go away |
| or be replaced if it's getting in the way. |
| |
| On ARM we need to know whether the ISA of rtld_db_dlactivity (or |
| however it's spelled in your particular system) is ARM or Thumb. |
| That knowledge is encoded in the address, if it's Thumb the low bit |
| is 1. However, we've stripped that info above and it's not clear |
| what all the consequences are of passing a non-addr_bits_remove'd |
| address to svr4_create_solib_event_breakpoints. The call to |
| find_pc_section verifies we know about the address and have some |
| hope of computing the right kind of breakpoint to use (via |
| symbol info). It does mean that GDB needs to be pointed at a |
| non-stripped version of the dynamic linker in order to obtain |
| information it already knows about. Sigh. */ |
| |
| os = find_pc_section (sym_addr); |
| if (os != NULL) |
| { |
| /* Record the relocated start and end address of the dynamic linker |
| text and plt section for svr4_in_dynsym_resolve_code. */ |
| bfd *tmp_bfd; |
| CORE_ADDR load_addr; |
| |
| tmp_bfd = os->objfile->obfd; |
| load_addr = ANOFFSET (os->objfile->section_offsets, |
| SECT_OFF_TEXT (os->objfile)); |
| |
| interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
| if (interp_sect) |
| { |
| info->interp_text_sect_low = |
| bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| info->interp_text_sect_high = |
| info->interp_text_sect_low |
| + bfd_section_size (tmp_bfd, interp_sect); |
| } |
| interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); |
| if (interp_sect) |
| { |
| info->interp_plt_sect_low = |
| bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| info->interp_plt_sect_high = |
| info->interp_plt_sect_low |
| + bfd_section_size (tmp_bfd, interp_sect); |
| } |
| |
| svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr); |
| return 1; |
| } |
| } |
| |
| /* Find the program interpreter; if not found, warn the user and drop |
| into the old breakpoint at symbol code. */ |
| interp_name = find_program_interpreter (); |
| if (interp_name) |
| { |
| CORE_ADDR load_addr = 0; |
| int load_addr_found = 0; |
| int loader_found_in_list = 0; |
| struct so_list *so; |
| bfd *tmp_bfd = NULL; |
| struct target_ops *tmp_bfd_target; |
| |
| sym_addr = 0; |
| |
| /* Now we need to figure out where the dynamic linker was |
| loaded so that we can load its symbols and place a breakpoint |
| in the dynamic linker itself. |
| |
| This address is stored on the stack. However, I've been unable |
| to find any magic formula to find it for Solaris (appears to |
| be trivial on GNU/Linux). Therefore, we have to try an alternate |
| mechanism to find the dynamic linker's base address. */ |
| |
| TRY |
| { |
| tmp_bfd = solib_bfd_open (interp_name); |
| } |
| CATCH (ex, RETURN_MASK_ALL) |
| { |
| } |
| END_CATCH |
| |
| if (tmp_bfd == NULL) |
| goto bkpt_at_symbol; |
| |
| /* Now convert the TMP_BFD into a target. That way target, as |
| well as BFD operations can be used. */ |
| tmp_bfd_target = target_bfd_reopen (tmp_bfd); |
| /* target_bfd_reopen acquired its own reference, so we can |
| release ours now. */ |
| gdb_bfd_unref (tmp_bfd); |
| |
| /* On a running target, we can get the dynamic linker's base |
| address from the shared library table. */ |
| so = master_so_list (); |
| while (so) |
| { |
| if (svr4_same_1 (interp_name, so->so_original_name)) |
| { |
| load_addr_found = 1; |
| loader_found_in_list = 1; |
| load_addr = lm_addr_check (so, tmp_bfd); |
| break; |
| } |
| so = so->next; |
| } |
| |
| /* If we were not able to find the base address of the loader |
| from our so_list, then try using the AT_BASE auxilliary entry. */ |
| if (!load_addr_found) |
| if (target_auxv_search (¤t_target, AT_BASE, &load_addr) > 0) |
| { |
| int addr_bit = gdbarch_addr_bit (target_gdbarch ()); |
| |
| /* Ensure LOAD_ADDR has proper sign in its possible upper bits so |
| that `+ load_addr' will overflow CORE_ADDR width not creating |
| invalid addresses like 0x101234567 for 32bit inferiors on 64bit |
| GDB. */ |
| |
| if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT)) |
| { |
| CORE_ADDR space_size = (CORE_ADDR) 1 << addr_bit; |
| CORE_ADDR tmp_entry_point = exec_entry_point (tmp_bfd, |
| tmp_bfd_target); |
| |
| gdb_assert (load_addr < space_size); |
| |
| /* TMP_ENTRY_POINT exceeding SPACE_SIZE would be for prelinked |
| 64bit ld.so with 32bit executable, it should not happen. */ |
| |
| if (tmp_entry_point < space_size |
| && tmp_entry_point + load_addr >= space_size) |
| load_addr -= space_size; |
| } |
| |
| load_addr_found = 1; |
| } |
| |
| /* Otherwise we find the dynamic linker's base address by examining |
| the current pc (which should point at the entry point for the |
| dynamic linker) and subtracting the offset of the entry point. |
| |
| This is more fragile than the previous approaches, but is a good |
| fallback method because it has actually been working well in |
| most cases. */ |
| if (!load_addr_found) |
| { |
| struct regcache *regcache |
| = get_thread_arch_regcache (inferior_ptid, target_gdbarch ()); |
| |
| load_addr = (regcache_read_pc (regcache) |
| - exec_entry_point (tmp_bfd, tmp_bfd_target)); |
| } |
| |
| if (!loader_found_in_list) |
| { |
| info->debug_loader_name = xstrdup (interp_name); |
| info->debug_loader_offset_p = 1; |
| info->debug_loader_offset = load_addr; |
| solib_add (NULL, from_tty, ¤t_target, auto_solib_add); |
| } |
| |
| /* Record the relocated start and end address of the dynamic linker |
| text and plt section for svr4_in_dynsym_resolve_code. */ |
| interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
| if (interp_sect) |
| { |
| info->interp_text_sect_low = |
| bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| info->interp_text_sect_high = |
| info->interp_text_sect_low |
| + bfd_section_size (tmp_bfd, interp_sect); |
| } |
| interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); |
| if (interp_sect) |
| { |
| info->interp_plt_sect_low = |
| bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| info->interp_plt_sect_high = |
| info->interp_plt_sect_low |
| + bfd_section_size (tmp_bfd, interp_sect); |
| } |
| |
| /* Now try to set a breakpoint in the dynamic linker. */ |
| for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) |
| { |
| sym_addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name_and_sec_flags, |
| *bkpt_namep); |
| if (sym_addr != 0) |
| break; |
| } |
| |
| if (sym_addr != 0) |
| /* Convert 'sym_addr' from a function pointer to an address. |
| Because we pass tmp_bfd_target instead of the current |
| target, this will always produce an unrelocated value. */ |
| sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| sym_addr, |
| tmp_bfd_target); |
| |
| /* We're done with both the temporary bfd and target. Closing |
| the target closes the underlying bfd, because it holds the |
| only remaining reference. */ |
| target_close (tmp_bfd_target); |
| |
| if (sym_addr != 0) |
| { |
| svr4_create_solib_event_breakpoints (target_gdbarch (), |
| load_addr + sym_addr); |
| xfree (interp_name); |
| return 1; |
| } |
| |
| /* For whatever reason we couldn't set a breakpoint in the dynamic |
| linker. Warn and drop into the old code. */ |
| bkpt_at_symbol: |
| xfree (interp_name); |
| warning (_("Unable to find dynamic linker breakpoint function.\n" |
| "GDB will be unable to debug shared library initializers\n" |
| "and track explicitly loaded dynamic code.")); |
| } |
| |
| /* Scan through the lists of symbols, trying to look up the symbol and |
| set a breakpoint there. Terminate loop when we/if we succeed. */ |
| |
| for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++) |
| { |
| msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); |
| if ((msymbol.minsym != NULL) |
| && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| { |
| sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol); |
| sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| sym_addr, |
| ¤t_target); |
| svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr); |
| return 1; |
| } |
| } |
| |
| if (interp_name != NULL && !current_inferior ()->attach_flag) |
| { |
| for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) |
| { |
| msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); |
| if ((msymbol.minsym != NULL) |
| && (BMSYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| { |
| sym_addr = BMSYMBOL_VALUE_ADDRESS (msymbol); |
| sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), |
| sym_addr, |
| ¤t_target); |
| svr4_create_solib_event_breakpoints (target_gdbarch (), sym_addr); |
| return 1; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| /* Read the ELF program headers from ABFD. Return the contents and |
| set *PHDRS_SIZE to the size of the program headers. */ |
| |
| static gdb_byte * |
| read_program_headers_from_bfd (bfd *abfd, int *phdrs_size) |
| { |
| Elf_Internal_Ehdr *ehdr; |
| gdb_byte *buf; |
| |
| ehdr = elf_elfheader (abfd); |
| |
| *phdrs_size = ehdr->e_phnum * ehdr->e_phentsize; |
| if (*phdrs_size == 0) |
| return NULL; |
| |
| buf = (gdb_byte *) xmalloc (*phdrs_size); |
| if (bfd_seek (abfd, ehdr->e_phoff, SEEK_SET) != 0 |
| || bfd_bread (buf, *phdrs_size, abfd) != *phdrs_size) |
| { |
| xfree (buf); |
| return NULL; |
| } |
| |
| return buf; |
| } |
| |
| /* Return 1 and fill *DISPLACEMENTP with detected PIE offset of inferior |
| exec_bfd. Otherwise return 0. |
| |
| We relocate all of the sections by the same amount. This |
| behavior is mandated by recent editions of the System V ABI. |
| According to the System V Application Binary Interface, |
| Edition 4.1, page 5-5: |
| |
| ... Though the system chooses virtual addresses for |
| individual processes, it maintains the segments' relative |
| positions. Because position-independent code uses relative |
| addressesing between segments, the difference between |
| virtual addresses in memory must match the difference |
| between virtual addresses in the file. The difference |
| between the virtual address of any segment in memory and |
| the corresponding virtual address in the file is thus a |
| single constant value for any one executable or shared |
| object in a given process. This difference is the base |
| address. One use of the base address is to relocate the |
| memory image of the program during dynamic linking. |
| |
| The same language also appears in Edition 4.0 of the System V |
| ABI and is left unspecified in some of the earlier editions. |
| |
| Decide if the objfile needs to be relocated. As indicated above, we will |
| only be here when execution is stopped. But during attachment PC can be at |
| arbitrary address therefore regcache_read_pc can be misleading (contrary to |
| the auxv AT_ENTRY value). Moreover for executable with interpreter section |
| regcache_read_pc would point to the interpreter and not the main executable. |
| |
| So, to summarize, relocations are necessary when the start address obtained |
| from the executable is different from the address in auxv AT_ENTRY entry. |
| |
| [ The astute reader will note that we also test to make sure that |
| the executable in question has the DYNAMIC flag set. It is my |
| opinion that this test is unnecessary (undesirable even). It |
| was added to avoid inadvertent relocation of an executable |
| whose e_type member in the ELF header is not ET_DYN. There may |
| be a time in the future when it is desirable to do relocations |
| on other types of files as well in which case this condition |
| should either be removed or modified to accomodate the new file |
| type. - Kevin, Nov 2000. ] */ |
| |
| static int |
| svr4_exec_displacement (CORE_ADDR *displacementp) |
| { |
| /* ENTRY_POINT is a possible function descriptor - before |
| a call to gdbarch_convert_from_func_ptr_addr. */ |
| CORE_ADDR entry_point, exec_displacement; |
| |
| if (exec_bfd == NULL) |
| return 0; |
| |
| /* Therefore for ELF it is ET_EXEC and not ET_DYN. Both shared libraries |
| being executed themselves and PIE (Position Independent Executable) |
| executables are ET_DYN. */ |
| |
| if ((bfd_get_file_flags (exec_bfd) & DYNAMIC) == 0) |
| return 0; |
| |
| if (target_auxv_search (¤t_target, AT_ENTRY, &entry_point) <= 0) |
| return 0; |
| |
| exec_displacement = entry_point - bfd_get_start_address (exec_bfd); |
| |
| /* Verify the EXEC_DISPLACEMENT candidate complies with the required page |
| alignment. It is cheaper than the program headers comparison below. */ |
| |
| if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| { |
| const struct elf_backend_data *elf = get_elf_backend_data (exec_bfd); |
| |
| /* p_align of PT_LOAD segments does not specify any alignment but |
| only congruency of addresses: |
| p_offset % p_align == p_vaddr % p_align |
| Kernel is free to load the executable with lower alignment. */ |
| |
| if ((exec_displacement & (elf->minpagesize - 1)) != 0) |
| return 0; |
| } |
| |
| /* Verify that the auxilliary vector describes the same file as exec_bfd, by |
| comparing their program headers. If the program headers in the auxilliary |
| vector do not match the program headers in the executable, then we are |
| looking at a different file than the one used by the kernel - for |
| instance, "gdb program" connected to "gdbserver :PORT ld.so program". */ |
| |
| if (bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| { |
| /* Be optimistic and clear OK only if GDB was able to verify the headers |
| really do not match. */ |
| int phdrs_size, phdrs2_size, ok = 1; |
| gdb_byte *buf, *buf2; |
| int arch_size; |
| |
| buf = read_program_header (-1, &phdrs_size, &arch_size, NULL); |
| buf2 = read_program_headers_from_bfd (exec_bfd, &phdrs2_size); |
| if (buf != NULL && buf2 != NULL) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| |
| /* We are dealing with three different addresses. EXEC_BFD |
| represents current address in on-disk file. target memory content |
| may be different from EXEC_BFD as the file may have been prelinked |
| to a different address after the executable has been loaded. |
| Moreover the address of placement in target memory can be |
| different from what the program headers in target memory say - |
| this is the goal of PIE. |
| |
| Detected DISPLACEMENT covers both the offsets of PIE placement and |
| possible new prelink performed after start of the program. Here |
| relocate BUF and BUF2 just by the EXEC_BFD vs. target memory |
| content offset for the verification purpose. */ |
| |
| if (phdrs_size != phdrs2_size |
| || bfd_get_arch_size (exec_bfd) != arch_size) |
| ok = 0; |
| else if (arch_size == 32 |
| && phdrs_size >= sizeof (Elf32_External_Phdr) |
| && phdrs_size % sizeof (Elf32_External_Phdr) == 0) |
| { |
| Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header; |
| Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr; |
| CORE_ADDR displacement = 0; |
| int i; |
| |
| /* DISPLACEMENT could be found more easily by the difference of |
| ehdr2->e_entry. But we haven't read the ehdr yet, and we |
| already have enough information to compute that displacement |
| with what we've read. */ |
| |
| for (i = 0; i < ehdr2->e_phnum; i++) |
| if (phdr2[i].p_type == PT_LOAD) |
| { |
| Elf32_External_Phdr *phdrp; |
| gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| CORE_ADDR vaddr, paddr; |
| CORE_ADDR displacement_vaddr = 0; |
| CORE_ADDR displacement_paddr = 0; |
| |
| phdrp = &((Elf32_External_Phdr *) buf)[i]; |
| buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| |
| vaddr = extract_unsigned_integer (buf_vaddr_p, 4, |
| byte_order); |
| displacement_vaddr = vaddr - phdr2[i].p_vaddr; |
| |
| paddr = extract_unsigned_integer (buf_paddr_p, 4, |
| byte_order); |
| displacement_paddr = paddr - phdr2[i].p_paddr; |
| |
| if (displacement_vaddr == displacement_paddr) |
| displacement = displacement_vaddr; |
| |
| break; |
| } |
| |
| /* Now compare BUF and BUF2 with optional DISPLACEMENT. */ |
| |
| for (i = 0; i < phdrs_size / sizeof (Elf32_External_Phdr); i++) |
| { |
| Elf32_External_Phdr *phdrp; |
| Elf32_External_Phdr *phdr2p; |
| gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| CORE_ADDR vaddr, paddr; |
| asection *plt2_asect; |
| |
| phdrp = &((Elf32_External_Phdr *) buf)[i]; |
| buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| phdr2p = &((Elf32_External_Phdr *) buf2)[i]; |
| |
| /* PT_GNU_STACK is an exception by being never relocated by |
| prelink as its addresses are always zero. */ |
| |
| if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| continue; |
| |
| /* Check also other adjustment combinations - PR 11786. */ |
| |
| vaddr = extract_unsigned_integer (buf_vaddr_p, 4, |
| byte_order); |
| vaddr -= displacement; |
| store_unsigned_integer (buf_vaddr_p, 4, byte_order, vaddr); |
| |
| paddr = extract_unsigned_integer (buf_paddr_p, 4, |
| byte_order); |
| paddr -= displacement; |
| store_unsigned_integer (buf_paddr_p, 4, byte_order, paddr); |
| |
| if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| continue; |
| |
| /* Strip modifies the flags and alignment of PT_GNU_RELRO. |
| CentOS-5 has problems with filesz, memsz as well. |
| See PR 11786. */ |
| if (phdr2[i].p_type == PT_GNU_RELRO) |
| { |
| Elf32_External_Phdr tmp_phdr = *phdrp; |
| Elf32_External_Phdr tmp_phdr2 = *phdr2p; |
| |
| memset (tmp_phdr.p_filesz, 0, 4); |
| memset (tmp_phdr.p_memsz, 0, 4); |
| memset (tmp_phdr.p_flags, 0, 4); |
| memset (tmp_phdr.p_align, 0, 4); |
| memset (tmp_phdr2.p_filesz, 0, 4); |
| memset (tmp_phdr2.p_memsz, 0, 4); |
| memset (tmp_phdr2.p_flags, 0, 4); |
| memset (tmp_phdr2.p_align, 0, 4); |
| |
| if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr)) |
| == 0) |
| continue; |
| } |
| |
| /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */ |
| plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt"); |
| if (plt2_asect) |
| { |
| int content2; |
| gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz; |
| CORE_ADDR filesz; |
| |
| content2 = (bfd_get_section_flags (exec_bfd, plt2_asect) |
| & SEC_HAS_CONTENTS) != 0; |
| |
| filesz = extract_unsigned_integer (buf_filesz_p, 4, |
| byte_order); |
| |
| /* PLT2_ASECT is from on-disk file (exec_bfd) while |
| FILESZ is from the in-memory image. */ |
| if (content2) |
| filesz += bfd_get_section_size (plt2_asect); |
| else |
| filesz -= bfd_get_section_size (plt2_asect); |
| |
| store_unsigned_integer (buf_filesz_p, 4, byte_order, |
| filesz); |
| |
| if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| continue; |
| } |
| |
| ok = 0; |
| break; |
| } |
| } |
| else if (arch_size == 64 |
| && phdrs_size >= sizeof (Elf64_External_Phdr) |
| && phdrs_size % sizeof (Elf64_External_Phdr) == 0) |
| { |
| Elf_Internal_Ehdr *ehdr2 = elf_tdata (exec_bfd)->elf_header; |
| Elf_Internal_Phdr *phdr2 = elf_tdata (exec_bfd)->phdr; |
| CORE_ADDR displacement = 0; |
| int i; |
| |
| /* DISPLACEMENT could be found more easily by the difference of |
| ehdr2->e_entry. But we haven't read the ehdr yet, and we |
| already have enough information to compute that displacement |
| with what we've read. */ |
| |
| for (i = 0; i < ehdr2->e_phnum; i++) |
| if (phdr2[i].p_type == PT_LOAD) |
| { |
| Elf64_External_Phdr *phdrp; |
| gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| CORE_ADDR vaddr, paddr; |
| CORE_ADDR displacement_vaddr = 0; |
| CORE_ADDR displacement_paddr = 0; |
| |
| phdrp = &((Elf64_External_Phdr *) buf)[i]; |
| buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| |
| vaddr = extract_unsigned_integer (buf_vaddr_p, 8, |
| byte_order); |
| displacement_vaddr = vaddr - phdr2[i].p_vaddr; |
| |
| paddr = extract_unsigned_integer (buf_paddr_p, 8, |
| byte_order); |
| displacement_paddr = paddr - phdr2[i].p_paddr; |
| |
| if (displacement_vaddr == displacement_paddr) |
| displacement = displacement_vaddr; |
| |
| break; |
| } |
| |
| /* Now compare BUF and BUF2 with optional DISPLACEMENT. */ |
| |
| for (i = 0; i < phdrs_size / sizeof (Elf64_External_Phdr); i++) |
| { |
| Elf64_External_Phdr *phdrp; |
| Elf64_External_Phdr *phdr2p; |
| gdb_byte *buf_vaddr_p, *buf_paddr_p; |
| CORE_ADDR vaddr, paddr; |
| asection *plt2_asect; |
| |
| phdrp = &((Elf64_External_Phdr *) buf)[i]; |
| buf_vaddr_p = (gdb_byte *) &phdrp->p_vaddr; |
| buf_paddr_p = (gdb_byte *) &phdrp->p_paddr; |
| phdr2p = &((Elf64_External_Phdr *) buf2)[i]; |
| |
| /* PT_GNU_STACK is an exception by being never relocated by |
| prelink as its addresses are always zero. */ |
| |
| if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| continue; |
| |
| /* Check also other adjustment combinations - PR 11786. */ |
| |
| vaddr = extract_unsigned_integer (buf_vaddr_p, 8, |
| byte_order); |
| vaddr -= displacement; |
| store_unsigned_integer (buf_vaddr_p, 8, byte_order, vaddr); |
| |
| paddr = extract_unsigned_integer (buf_paddr_p, 8, |
| byte_order); |
| paddr -= displacement; |
| store_unsigned_integer (buf_paddr_p, 8, byte_order, paddr); |
| |
| if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| continue; |
| |
| /* Strip modifies the flags and alignment of PT_GNU_RELRO. |
| CentOS-5 has problems with filesz, memsz as well. |
| See PR 11786. */ |
| if (phdr2[i].p_type == PT_GNU_RELRO) |
| { |
| Elf64_External_Phdr tmp_phdr = *phdrp; |
| Elf64_External_Phdr tmp_phdr2 = *phdr2p; |
| |
| memset (tmp_phdr.p_filesz, 0, 8); |
| memset (tmp_phdr.p_memsz, 0, 8); |
| memset (tmp_phdr.p_flags, 0, 4); |
| memset (tmp_phdr.p_align, 0, 8); |
| memset (tmp_phdr2.p_filesz, 0, 8); |
| memset (tmp_phdr2.p_memsz, 0, 8); |
| memset (tmp_phdr2.p_flags, 0, 4); |
| memset (tmp_phdr2.p_align, 0, 8); |
| |
| if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr)) |
| == 0) |
| continue; |
| } |
| |
| /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS. */ |
| plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt"); |
| if (plt2_asect) |
| { |
| int content2; |
| gdb_byte *buf_filesz_p = (gdb_byte *) &phdrp->p_filesz; |
| CORE_ADDR filesz; |
| |
| content2 = (bfd_get_section_flags (exec_bfd, plt2_asect) |
| & SEC_HAS_CONTENTS) != 0; |
| |
| filesz = extract_unsigned_integer (buf_filesz_p, 8, |
| byte_order); |
| |
| /* PLT2_ASECT is from on-disk file (exec_bfd) while |
| FILESZ is from the in-memory image. */ |
| if (content2) |
| filesz += bfd_get_section_size (plt2_asect); |
| else |
| filesz -= bfd_get_section_size (plt2_asect); |
| |
| store_unsigned_integer (buf_filesz_p, 8, byte_order, |
| filesz); |
| |
| if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0) |
| continue; |
| } |
| |
| ok = 0; |
| break; |
| } |
| } |
| else |
| ok = 0; |
| } |
| |
| xfree (buf); |
| xfree (buf2); |
| |
| if (!ok) |
| return 0; |
| } |
| |
| if (info_verbose) |
| { |
| /* It can be printed repeatedly as there is no easy way to check |
| the executable symbols/file has been already relocated to |
| displacement. */ |
| |
| printf_unfiltered (_("Using PIE (Position Independent Executable) " |
| "displacement %s for \"%s\".\n"), |
| paddress (target_gdbarch (), exec_displacement), |
| bfd_get_filename (exec_bfd)); |
| } |
| |
| *displacementp = exec_displacement; |
| return 1; |
| } |
| |
| /* See solib-svr4.h. */ |
| |
| void |
| svr4_relocate_main_executable (void) |
| { |
| CORE_ADDR displacement; |
| |
| /* If we are re-running this executable, SYMFILE_OBJFILE->SECTION_OFFSETS |
| probably contains the offsets computed using the PIE displacement |
| from the previous run, which of course are irrelevant for this run. |
| So we need to determine the new PIE displacement and recompute the |
| section offsets accordingly, even if SYMFILE_OBJFILE->SECTION_OFFSETS |
| already contains pre-computed offsets. |
| |
| If we cannot compute the PIE displacement, either: |
| |
| - The executable is not PIE. |
| |
| - SYMFILE_OBJFILE does not match the executable started in the target. |
| This can happen for main executable symbols loaded at the host while |
| `ld.so --ld-args main-executable' is loaded in the target. |
| |
| Then we leave the section offsets untouched and use them as is for |
| this run. Either: |
| |
| - These section offsets were properly reset earlier, and thus |
| already contain the correct values. This can happen for instance |
| when reconnecting via the remote protocol to a target that supports |
| the `qOffsets' packet. |
| |
| - The section offsets were not reset earlier, and the best we can |
| hope is that the old offsets are still applicable to the new run. */ |
| |
| if (! svr4_exec_displacement (&displacement)) |
| return; |
| |
| /* Even DISPLACEMENT 0 is a valid new difference of in-memory vs. in-file |
| addresses. */ |
| |
| if (symfile_objfile) |
| { |
| struct section_offsets *new_offsets; |
| int i; |
| |
| new_offsets = XALLOCAVEC (struct section_offsets, |
| symfile_objfile->num_sections); |
| |
| for (i = 0; i < symfile_objfile->num_sections; i++) |
| new_offsets->offsets[i] = displacement; |
| |
| objfile_relocate (symfile_objfile, new_offsets); |
| } |
| else if (exec_bfd) |
| { |
| asection *asect; |
| |
| for (asect = exec_bfd->sections; asect != NULL; asect = asect->next) |
| exec_set_section_address (bfd_get_filename (exec_bfd), asect->index, |
| (bfd_section_vma (exec_bfd, asect) |
| + displacement)); |
| } |
| } |
| |
| /* Implement the "create_inferior_hook" target_solib_ops method. |
| |
| For SVR4 executables, this first instruction is either the first |
| instruction in the dynamic linker (for dynamically linked |
| executables) or the instruction at "start" for statically linked |
| executables. For dynamically linked executables, the system |
| first exec's /lib/libc.so.N, which contains the dynamic linker, |
| and starts it running. The dynamic linker maps in any needed |
| shared libraries, maps in the actual user executable, and then |
| jumps to "start" in the user executable. |
| |
| We can arrange to cooperate with the dynamic linker to discover the |
| names of shared libraries that are dynamically linked, and the base |
| addresses to which they are linked. |
| |
| This function is responsible for discovering those names and |
| addresses, and saving sufficient information about them to allow |
| their symbols to be read at a later time. */ |
| |
| static void |
| svr4_solib_create_inferior_hook (int from_tty) |
| { |
| struct svr4_info *info; |
| |
| info = get_svr4_info (); |
| |
| /* Clear the probes-based interface's state. */ |
| free_probes_table (info); |
| free_solib_list (info); |
| |
| /* Relocate the main executable if necessary. */ |
| svr4_relocate_main_executable (); |
| |
| /* No point setting a breakpoint in the dynamic linker if we can't |
| hit it (e.g., a core file, or a trace file). */ |
| if (!target_has_execution) |
| return; |
| |
| if (!svr4_have_link_map_offsets ()) |
| return; |
| |
| if (!enable_break (info, from_tty)) |
| return; |
| } |
| |
| static void |
| svr4_clear_solib (void) |
| { |
| struct svr4_info *info; |
| |
| info = get_svr4_info (); |
| info->debug_base = 0; |
| info->debug_loader_offset_p = 0; |
| info->debug_loader_offset = 0; |
| xfree (info->debug_loader_name); |
| info->debug_loader_name = NULL; |
| } |
| |
| /* Clear any bits of ADDR that wouldn't fit in a target-format |
| data pointer. "Data pointer" here refers to whatever sort of |
| address the dynamic linker uses to manage its sections. At the |
| moment, we don't support shared libraries on any processors where |
| code and data pointers are different sizes. |
| |
| This isn't really the right solution. What we really need here is |
| a way to do arithmetic on CORE_ADDR values that respects the |
| natural pointer/address correspondence. (For example, on the MIPS, |
| converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to |
| sign-extend the value. There, simply truncating the bits above |
| gdbarch_ptr_bit, as we do below, is no good.) This should probably |
| be a new gdbarch method or something. */ |
| static CORE_ADDR |
| svr4_truncate_ptr (CORE_ADDR addr) |
| { |
| if (gdbarch_ptr_bit (target_gdbarch ()) == sizeof (CORE_ADDR) * 8) |
| /* We don't need to truncate anything, and the bit twiddling below |
| will fail due to overflow problems. */ |
| return addr; |
| else |
| return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (target_gdbarch ())) - 1); |
| } |
| |
| |
| static void |
| svr4_relocate_section_addresses (struct so_list *so, |
| struct target_section *sec) |
| { |
| bfd *abfd = sec->the_bfd_section->owner; |
| |
| sec->addr = svr4_truncate_ptr (sec->addr + lm_addr_check (so, abfd)); |
| sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so, abfd)); |
| } |
| |
| |
| /* Architecture-specific operations. */ |
| |
| /* Per-architecture data key. */ |
| static struct gdbarch_data *solib_svr4_data; |
| |
| struct solib_svr4_ops |
| { |
| /* Return a description of the layout of `struct link_map'. */ |
| struct link_map_offsets *(*fetch_link_map_offsets)(void); |
| }; |
| |
| /* Return a default for the architecture-specific operations. */ |
| |
| static void * |
| solib_svr4_init (struct obstack *obstack) |
| { |
| struct solib_svr4_ops *ops; |
| |
| ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops); |
| ops->fetch_link_map_offsets = NULL; |
| return ops; |
| } |
| |
| /* Set the architecture-specific `struct link_map_offsets' fetcher for |
| GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */ |
| |
| void |
| set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch, |
| struct link_map_offsets *(*flmo) (void)) |
| { |
| struct solib_svr4_ops *ops |
| = (struct solib_svr4_ops *) gdbarch_data (gdbarch, solib_svr4_data); |
| |
| ops->fetch_link_map_offsets = flmo; |
| |
| set_solib_ops (gdbarch, &svr4_so_ops); |
| } |
| |
| /* Fetch a link_map_offsets structure using the architecture-specific |
| `struct link_map_offsets' fetcher. */ |
| |
| static struct link_map_offsets * |
| svr4_fetch_link_map_offsets (void) |
| { |
| struct solib_svr4_ops *ops |
| = (struct solib_svr4_ops *) gdbarch_data (target_gdbarch (), |
| solib_svr4_data); |
| |
| gdb_assert (ops->fetch_link_map_offsets); |
| return ops->fetch_link_map_offsets (); |
| } |
| |
| /* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */ |
| |
| static int |
| svr4_have_link_map_offsets (void) |
| { |
| struct solib_svr4_ops *ops |
| = (struct solib_svr4_ops *) gdbarch_data (target_gdbarch (), |
| solib_svr4_data); |
| |
| return (ops->fetch_link_map_offsets != NULL); |
| } |
| |
| |
| /* Most OS'es that have SVR4-style ELF dynamic libraries define a |
| `struct r_debug' and a `struct link_map' that are binary compatible |
| with the origional SVR4 implementation. */ |
| |
| /* Fetch (and possibly build) an appropriate `struct link_map_offsets' |
| for an ILP32 SVR4 system. */ |
| |
| struct link_map_offsets * |
| svr4_ilp32_fetch_link_map_offsets (void) |
| { |
| static struct link_map_offsets lmo; |
| static struct link_map_offsets *lmp = NULL; |
| |
| if (lmp == NULL) |
| { |
| lmp = &lmo; |
| |
| lmo.r_version_offset = 0; |
| lmo.r_version_size = 4; |
| lmo.r_map_offset = 4; |
| lmo.r_brk_offset = 8; |
| lmo.r_ldsomap_offset = 20; |
| |
| /* Everything we need is in the first 20 bytes. */ |
| lmo.link_map_size = 20; |
| lmo.l_addr_offset = 0; |
| lmo.l_name_offset = 4; |
| lmo.l_ld_offset = 8; |
| lmo.l_next_offset = 12; |
| lmo.l_prev_offset = 16; |
| } |
| |
| return lmp; |
| } |
| |
| /* Fetch (and possibly build) an appropriate `struct link_map_offsets' |
| for an LP64 SVR4 system. */ |
| |
| struct link_map_offsets * |
| svr4_lp64_fetch_link_map_offsets (void) |
| { |
| static struct link_map_offsets lmo; |
| static struct link_map_offsets *lmp = NULL; |
| |
| if (lmp == NULL) |
| { |
| lmp = &lmo; |
| |
| lmo.r_version_offset = 0; |
| lmo.r_version_size = 4; |
| lmo.r_map_offset = 8; |
| lmo.r_brk_offset = 16; |
| lmo.r_ldsomap_offset = 40; |
| |
| /* Everything we need is in the first 40 bytes. */ |
| lmo.link_map_size = 40; |
| lmo.l_addr_offset = 0; |
| lmo.l_name_offset = 8; |
| lmo.l_ld_offset = 16; |
| lmo.l_next_offset = 24; |
| lmo.l_prev_offset = 32; |
| } |
| |
| return lmp; |
| } |
| |
| |
| struct target_so_ops svr4_so_ops; |
| |
| /* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a |
| different rule for symbol lookup. The lookup begins here in the DSO, not in |
| the main executable. */ |
| |
| static struct block_symbol |
| elf_lookup_lib_symbol (struct objfile *objfile, |
| const char *name, |
| const domain_enum domain) |
| { |
| bfd *abfd; |
| |
| if (objfile == symfile_objfile) |
| abfd = exec_bfd; |
| else |
| { |
| /* OBJFILE should have been passed as the non-debug one. */ |
| gdb_assert (objfile->separate_debug_objfile_backlink == NULL); |
| |
| abfd = objfile->obfd; |
| } |
| |
| if (abfd == NULL || scan_dyntag (DT_SYMBOLIC, abfd, NULL, NULL) != 1) |
| return (struct block_symbol) {NULL, NULL}; |
| |
| return lookup_global_symbol_from_objfile (objfile, name, domain); |
| } |
| |
| extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */ |
| |
| void |
| _initialize_svr4_solib (void) |
| { |
| solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init); |
| solib_svr4_pspace_data |
| = register_program_space_data_with_cleanup (NULL, svr4_pspace_data_cleanup); |
| |
| svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses; |
| svr4_so_ops.free_so = svr4_free_so; |
| svr4_so_ops.clear_so = svr4_clear_so; |
| svr4_so_ops.clear_solib = svr4_clear_solib; |
| svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook; |
| svr4_so_ops.current_sos = svr4_current_sos;
|