| /* Handle SunOS and SVR4 shared libraries for GDB, the GNU Debugger. |
| Copyright 1990, 91, 92, 93, 94, 95, 96, 98, 1999 |
| 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 2 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, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| |
| #include "defs.h" |
| |
| /* This file is only compilable if link.h is available. */ |
| |
| #ifdef HAVE_LINK_H |
| |
| #include <sys/types.h> |
| #include <signal.h> |
| #include "gdb_string.h" |
| #include <sys/param.h> |
| #include <fcntl.h> |
| |
| #ifndef SVR4_SHARED_LIBS |
| /* SunOS shared libs need the nlist structure. */ |
| #include <a.out.h> |
| #else |
| #include "elf/external.h" |
| #endif |
| |
| #include <link.h> |
| |
| #include "symtab.h" |
| #include "bfd.h" |
| #include "symfile.h" |
| #include "objfiles.h" |
| #include "gdbcore.h" |
| #include "command.h" |
| #include "target.h" |
| #include "frame.h" |
| #include "gnu-regex.h" |
| #include "inferior.h" |
| #include "environ.h" |
| #include "language.h" |
| #include "gdbcmd.h" |
| |
| #define MAX_PATH_SIZE 512 /* FIXME: Should be dynamic */ |
| |
| /* 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. */ |
| |
| #ifdef SVR4_SHARED_LIBS |
| static char *solib_break_names[] = |
| { |
| "r_debug_state", |
| "_r_debug_state", |
| "_dl_debug_state", |
| "rtld_db_dlactivity", |
| NULL |
| }; |
| #endif |
| |
| #define BKPT_AT_SYMBOL 1 |
| |
| #if defined (BKPT_AT_SYMBOL) && defined (SVR4_SHARED_LIBS) |
| static char *bkpt_names[] = |
| { |
| #ifdef SOLIB_BKPT_NAME |
| SOLIB_BKPT_NAME, /* Prefer configured name if it exists. */ |
| #endif |
| "_start", |
| "main", |
| NULL |
| }; |
| #endif |
| |
| /* Symbols which are used to locate the base of the link map structures. */ |
| |
| #ifndef SVR4_SHARED_LIBS |
| static char *debug_base_symbols[] = |
| { |
| "_DYNAMIC", |
| "_DYNAMIC__MGC", |
| NULL |
| }; |
| #endif |
| |
| static char *main_name_list[] = |
| { |
| "main_$main", |
| NULL |
| }; |
| |
| /* local data declarations */ |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| #define LM_ADDR(so) ((so) -> lm.lm_addr) |
| #define LM_NEXT(so) ((so) -> lm.lm_next) |
| #define LM_NAME(so) ((so) -> lm.lm_name) |
| /* Test for first link map entry; first entry is a shared library. */ |
| #define IGNORE_FIRST_LINK_MAP_ENTRY(x) (0) |
| static struct link_dynamic dynamic_copy; |
| static struct link_dynamic_2 ld_2_copy; |
| static struct ld_debug debug_copy; |
| static CORE_ADDR debug_addr; |
| static CORE_ADDR flag_addr; |
| |
| #else /* SVR4_SHARED_LIBS */ |
| |
| #define LM_ADDR(so) ((so) -> lm.l_addr) |
| #define LM_NEXT(so) ((so) -> lm.l_next) |
| #define LM_NAME(so) ((so) -> lm.l_name) |
| /* Test for first link map entry; first entry is the exec-file. */ |
| #define IGNORE_FIRST_LINK_MAP_ENTRY(x) ((x).l_prev == NULL) |
| static struct r_debug debug_copy; |
| char shadow_contents[BREAKPOINT_MAX]; /* Stash old bkpt addr contents */ |
| |
| #endif /* !SVR4_SHARED_LIBS */ |
| |
| struct so_list |
| { |
| struct so_list *next; /* next structure in linked list */ |
| struct link_map lm; /* copy of link map from inferior */ |
| struct link_map *lmaddr; /* addr in inferior lm was read from */ |
| CORE_ADDR lmend; /* upper addr bound of mapped object */ |
| char so_name[MAX_PATH_SIZE]; /* shared object lib name (FIXME) */ |
| char symbols_loaded; /* flag: symbols read in yet? */ |
| char from_tty; /* flag: print msgs? */ |
| struct objfile *objfile; /* objfile for loaded lib */ |
| struct section_table *sections; |
| struct section_table *sections_end; |
| struct section_table *textsection; |
| bfd *abfd; |
| }; |
| |
| static struct so_list *so_list_head; /* List of known shared objects */ |
| static CORE_ADDR debug_base; /* Base of dynamic linker structures */ |
| static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */ |
| |
| static int solib_cleanup_queued = 0; /* make_run_cleanup called */ |
| |
| extern int |
| fdmatch PARAMS ((int, int)); /* In libiberty */ |
| |
| /* Local function prototypes */ |
| |
| static void |
| do_clear_solib PARAMS ((PTR)); |
| |
| static int |
| match_main PARAMS ((char *)); |
| |
| static void |
| special_symbol_handling PARAMS ((struct so_list *)); |
| |
| static void |
| sharedlibrary_command PARAMS ((char *, int)); |
| |
| static int |
| enable_break PARAMS ((void)); |
| |
| static void |
| info_sharedlibrary_command PARAMS ((char *, int)); |
| |
| static int symbol_add_stub PARAMS ((PTR)); |
| |
| static struct so_list * |
| find_solib PARAMS ((struct so_list *)); |
| |
| static struct link_map * |
| first_link_map_member PARAMS ((void)); |
| |
| static CORE_ADDR |
| locate_base PARAMS ((void)); |
| |
| static int solib_map_sections PARAMS ((PTR)); |
| |
| #ifdef SVR4_SHARED_LIBS |
| |
| static CORE_ADDR |
| elf_locate_base PARAMS ((void)); |
| |
| #else |
| |
| static int |
| disable_break PARAMS ((void)); |
| |
| static void |
| allocate_rt_common_objfile PARAMS ((void)); |
| |
| static void |
| solib_add_common_symbols PARAMS ((struct rtc_symb *)); |
| |
| #endif |
| |
| void _initialize_solib PARAMS ((void)); |
| |
| /* If non-zero, this is a prefix that will be added to the front of the name |
| shared libraries with an absolute filename for loading. */ |
| static char *solib_absolute_prefix = NULL; |
| |
| /* If non-empty, this is a search path for loading non-absolute shared library |
| symbol files. This takes precedence over the environment variables PATH |
| and LD_LIBRARY_PATH. */ |
| static char *solib_search_path = NULL; |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| solib_map_sections -- open bfd and build sections for shared lib |
| |
| SYNOPSIS |
| |
| static int solib_map_sections (struct so_list *so) |
| |
| DESCRIPTION |
| |
| Given a pointer to one of the shared objects in our list |
| of mapped objects, use the recorded name to open a bfd |
| descriptor for the object, build a section table, and then |
| relocate all the section addresses by the base address at |
| which the shared object was mapped. |
| |
| FIXMES |
| |
| In most (all?) cases the shared object file name recorded in the |
| dynamic linkage tables will be a fully qualified pathname. For |
| cases where it isn't, do we really mimic the systems search |
| mechanism correctly in the below code (particularly the tilde |
| expansion stuff?). |
| */ |
| |
| static int |
| solib_map_sections (arg) |
| PTR arg; |
| { |
| struct so_list *so = (struct so_list *) arg; /* catch_errors bogon */ |
| char *filename; |
| char *scratch_pathname; |
| int scratch_chan; |
| struct section_table *p; |
| struct cleanup *old_chain; |
| bfd *abfd; |
| |
| filename = tilde_expand (so->so_name); |
| |
| if (solib_absolute_prefix && ROOTED_P (filename)) |
| /* Prefix shared libraries with absolute filenames with |
| SOLIB_ABSOLUTE_PREFIX. */ |
| { |
| char *pfxed_fn; |
| int pfx_len; |
| |
| pfx_len = strlen (solib_absolute_prefix); |
| |
| /* Remove trailing slashes. */ |
| while (pfx_len > 0 && SLASH_P (solib_absolute_prefix[pfx_len - 1])) |
| pfx_len--; |
| |
| pfxed_fn = xmalloc (pfx_len + strlen (filename) + 1); |
| strcpy (pfxed_fn, solib_absolute_prefix); |
| strcat (pfxed_fn, filename); |
| free (filename); |
| |
| filename = pfxed_fn; |
| } |
| |
| old_chain = make_cleanup (free, filename); |
| |
| scratch_chan = -1; |
| |
| if (solib_search_path) |
| scratch_chan = openp (solib_search_path, |
| 1, filename, O_RDONLY, 0, &scratch_pathname); |
| if (scratch_chan < 0) |
| scratch_chan = openp (get_in_environ (inferior_environ, "PATH"), |
| 1, filename, O_RDONLY, 0, &scratch_pathname); |
| if (scratch_chan < 0) |
| { |
| scratch_chan = openp (get_in_environ |
| (inferior_environ, "LD_LIBRARY_PATH"), |
| 1, filename, O_RDONLY, 0, &scratch_pathname); |
| } |
| if (scratch_chan < 0) |
| { |
| perror_with_name (filename); |
| } |
| /* Leave scratch_pathname allocated. abfd->name will point to it. */ |
| |
| abfd = bfd_fdopenr (scratch_pathname, gnutarget, scratch_chan); |
| if (!abfd) |
| { |
| close (scratch_chan); |
| error ("Could not open `%s' as an executable file: %s", |
| scratch_pathname, bfd_errmsg (bfd_get_error ())); |
| } |
| /* Leave bfd open, core_xfer_memory and "info files" need it. */ |
| so->abfd = abfd; |
| abfd->cacheable = true; |
| |
| /* copy full path name into so_name, so that later symbol_file_add can find |
| it */ |
| if (strlen (scratch_pathname) >= MAX_PATH_SIZE) |
| error ("Full path name length of shared library exceeds MAX_PATH_SIZE in so_list structure."); |
| strcpy (so->so_name, scratch_pathname); |
| |
| if (!bfd_check_format (abfd, bfd_object)) |
| { |
| error ("\"%s\": not in executable format: %s.", |
| scratch_pathname, bfd_errmsg (bfd_get_error ())); |
| } |
| if (build_section_table (abfd, &so->sections, &so->sections_end)) |
| { |
| error ("Can't find the file sections in `%s': %s", |
| bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ())); |
| } |
| |
| for (p = so->sections; p < so->sections_end; p++) |
| { |
| /* Relocate the section binding addresses as recorded in the shared |
| object's file by the base address to which the object was actually |
| mapped. */ |
| p->addr += (CORE_ADDR) LM_ADDR (so); |
| p->endaddr += (CORE_ADDR) LM_ADDR (so); |
| so->lmend = (CORE_ADDR) max (p->endaddr, so->lmend); |
| if (STREQ (p->the_bfd_section->name, ".text")) |
| { |
| so->textsection = p; |
| } |
| } |
| |
| /* Free the file names, close the file now. */ |
| do_cleanups (old_chain); |
| |
| return (1); |
| } |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| /* Allocate the runtime common object file. */ |
| |
| static void |
| allocate_rt_common_objfile () |
| { |
| struct objfile *objfile; |
| struct objfile *last_one; |
| |
| objfile = (struct objfile *) xmalloc (sizeof (struct objfile)); |
| memset (objfile, 0, sizeof (struct objfile)); |
| objfile->md = NULL; |
| obstack_specify_allocation (&objfile->psymbol_cache.cache, 0, 0, |
| xmalloc, free); |
| obstack_specify_allocation (&objfile->psymbol_obstack, 0, 0, xmalloc, |
| free); |
| obstack_specify_allocation (&objfile->symbol_obstack, 0, 0, xmalloc, |
| free); |
| obstack_specify_allocation (&objfile->type_obstack, 0, 0, xmalloc, |
| free); |
| objfile->name = mstrsave (objfile->md, "rt_common"); |
| |
| /* Add this file onto the tail of the linked list of other such files. */ |
| |
| objfile->next = NULL; |
| if (object_files == NULL) |
| object_files = objfile; |
| else |
| { |
| for (last_one = object_files; |
| last_one->next; |
| last_one = last_one->next); |
| last_one->next = objfile; |
| } |
| |
| rt_common_objfile = objfile; |
| } |
| |
| /* Read all dynamically loaded common symbol definitions from the inferior |
| and put them into the minimal symbol table for the runtime common |
| objfile. */ |
| |
| static void |
| solib_add_common_symbols (rtc_symp) |
| struct rtc_symb *rtc_symp; |
| { |
| struct rtc_symb inferior_rtc_symb; |
| struct nlist inferior_rtc_nlist; |
| int len; |
| char *name; |
| |
| /* Remove any runtime common symbols from previous runs. */ |
| |
| if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count) |
| { |
| obstack_free (&rt_common_objfile->symbol_obstack, 0); |
| obstack_specify_allocation (&rt_common_objfile->symbol_obstack, 0, 0, |
| xmalloc, free); |
| rt_common_objfile->minimal_symbol_count = 0; |
| rt_common_objfile->msymbols = NULL; |
| } |
| |
| init_minimal_symbol_collection (); |
| make_cleanup ((make_cleanup_func) discard_minimal_symbols, 0); |
| |
| while (rtc_symp) |
| { |
| read_memory ((CORE_ADDR) rtc_symp, |
| (char *) &inferior_rtc_symb, |
| sizeof (inferior_rtc_symb)); |
| read_memory ((CORE_ADDR) inferior_rtc_symb.rtc_sp, |
| (char *) &inferior_rtc_nlist, |
| sizeof (inferior_rtc_nlist)); |
| if (inferior_rtc_nlist.n_type == N_COMM) |
| { |
| /* FIXME: The length of the symbol name is not available, but in the |
| current implementation the common symbol is allocated immediately |
| behind the name of the symbol. */ |
| len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx; |
| |
| name = xmalloc (len); |
| read_memory ((CORE_ADDR) inferior_rtc_nlist.n_un.n_name, name, len); |
| |
| /* Allocate the runtime common objfile if necessary. */ |
| if (rt_common_objfile == NULL) |
| allocate_rt_common_objfile (); |
| |
| prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value, |
| mst_bss, rt_common_objfile); |
| free (name); |
| } |
| rtc_symp = inferior_rtc_symb.rtc_next; |
| } |
| |
| /* Install any minimal symbols that have been collected as the current |
| minimal symbols for the runtime common objfile. */ |
| |
| install_minimal_symbols (rt_common_objfile); |
| } |
| |
| #endif /* SVR4_SHARED_LIBS */ |
| |
| |
| #ifdef SVR4_SHARED_LIBS |
| |
| static CORE_ADDR |
| bfd_lookup_symbol PARAMS ((bfd *, char *)); |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| bfd_lookup_symbol -- lookup the value for a specific symbol |
| |
| SYNOPSIS |
| |
| CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname) |
| |
| DESCRIPTION |
| |
| An expensive way to lookup the value of a single symbol for |
| bfd's that are only temporary anyway. This is used by the |
| shared library support to find the address of the debugger |
| interface structures in the shared library. |
| |
| Note that 0 is specifically allowed as an error return (no |
| such symbol). |
| */ |
| |
| static CORE_ADDR |
| bfd_lookup_symbol (abfd, symname) |
| bfd *abfd; |
| char *symname; |
| { |
| unsigned int storage_needed; |
| asymbol *sym; |
| asymbol **symbol_table; |
| unsigned int number_of_symbols; |
| unsigned int i; |
| struct cleanup *back_to; |
| CORE_ADDR symaddr = 0; |
| |
| storage_needed = bfd_get_symtab_upper_bound (abfd); |
| |
| if (storage_needed > 0) |
| { |
| symbol_table = (asymbol **) xmalloc (storage_needed); |
| back_to = make_cleanup (free, (PTR) symbol_table); |
| number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
| |
| for (i = 0; i < number_of_symbols; i++) |
| { |
| sym = *symbol_table++; |
| if (STREQ (sym->name, symname)) |
| { |
| /* Bfd symbols are section relative. */ |
| symaddr = sym->value + sym->section->vma; |
| break; |
| } |
| } |
| do_cleanups (back_to); |
| } |
| return (symaddr); |
| } |
| |
| #ifdef HANDLE_SVR4_EXEC_EMULATORS |
| |
| /* |
| Solaris BCP (the part of Solaris which allows it to run SunOS4 |
| a.out files) throws in another wrinkle. Solaris does not fill |
| in the usual a.out link map structures when running BCP programs, |
| the only way to get at them is via groping around in the dynamic |
| linker. |
| The dynamic linker and it's structures are located in the shared |
| C library, which gets run as the executable's "interpreter" by |
| the kernel. |
| |
| Note that we can assume nothing about the process state at the time |
| we need to find these structures. We may be stopped on the first |
| instruction of the interpreter (C shared library), the first |
| instruction of the executable itself, or somewhere else entirely |
| (if we attached to the process for example). |
| */ |
| |
| static char *debug_base_symbols[] = |
| { |
| "r_debug", /* Solaris 2.3 */ |
| "_r_debug", /* Solaris 2.1, 2.2 */ |
| NULL |
| }; |
| |
| static int |
| look_for_base PARAMS ((int, CORE_ADDR)); |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| look_for_base -- examine file for each mapped address segment |
| |
| SYNOPSYS |
| |
| static int look_for_base (int fd, CORE_ADDR baseaddr) |
| |
| DESCRIPTION |
| |
| This function is passed to proc_iterate_over_mappings, which |
| causes it to get called once for each mapped address space, with |
| an open file descriptor for the file mapped to that space, and the |
| base address of that mapped space. |
| |
| Our job is to find the debug base symbol in the file that this |
| fd is open on, if it exists, and if so, initialize the dynamic |
| linker structure base address debug_base. |
| |
| Note that this is a computationally expensive proposition, since |
| we basically have to open a bfd on every call, so we specifically |
| avoid opening the exec file. |
| */ |
| |
| static int |
| look_for_base (fd, baseaddr) |
| int fd; |
| CORE_ADDR baseaddr; |
| { |
| bfd *interp_bfd; |
| CORE_ADDR address = 0; |
| char **symbolp; |
| |
| /* If the fd is -1, then there is no file that corresponds to this |
| mapped memory segment, so skip it. Also, if the fd corresponds |
| to the exec file, skip it as well. */ |
| |
| if (fd == -1 |
| || (exec_bfd != NULL |
| && fdmatch (fileno ((FILE *) (exec_bfd->iostream)), fd))) |
| { |
| return (0); |
| } |
| |
| /* Try to open whatever random file this fd corresponds to. Note that |
| we have no way currently to find the filename. Don't gripe about |
| any problems we might have, just fail. */ |
| |
| if ((interp_bfd = bfd_fdopenr ("unnamed", gnutarget, fd)) == NULL) |
| { |
| return (0); |
| } |
| if (!bfd_check_format (interp_bfd, bfd_object)) |
| { |
| /* FIXME-leak: on failure, might not free all memory associated with |
| interp_bfd. */ |
| bfd_close (interp_bfd); |
| return (0); |
| } |
| |
| /* Now try to find our debug base symbol in this file, which we at |
| least know to be a valid ELF executable or shared library. */ |
| |
| for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++) |
| { |
| address = bfd_lookup_symbol (interp_bfd, *symbolp); |
| if (address != 0) |
| { |
| break; |
| } |
| } |
| if (address == 0) |
| { |
| /* FIXME-leak: on failure, might not free all memory associated with |
| interp_bfd. */ |
| bfd_close (interp_bfd); |
| return (0); |
| } |
| |
| /* Eureka! We found the symbol. But now we may need to relocate it |
| by the base address. If the symbol's value is less than the base |
| address of the shared library, then it hasn't yet been relocated |
| by the dynamic linker, and we have to do it ourself. FIXME: Note |
| that we make the assumption that the first segment that corresponds |
| to the shared library has the base address to which the library |
| was relocated. */ |
| |
| if (address < baseaddr) |
| { |
| address += baseaddr; |
| } |
| debug_base = address; |
| /* FIXME-leak: on failure, might not free all memory associated with |
| interp_bfd. */ |
| bfd_close (interp_bfd); |
| return (1); |
| } |
| #endif /* HANDLE_SVR4_EXEC_EMULATORS */ |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| elf_locate_base -- locate the base address of dynamic linker structs |
| for SVR4 elf targets. |
| |
| SYNOPSIS |
| |
| CORE_ADDR elf_locate_base (void) |
| |
| DESCRIPTION |
| |
| 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 () |
| { |
| sec_ptr dyninfo_sect; |
| int dyninfo_sect_size; |
| CORE_ADDR dyninfo_addr; |
| char *buf; |
| char *bufend; |
| |
| /* Find the start address of the .dynamic section. */ |
| dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic"); |
| if (dyninfo_sect == NULL) |
| return 0; |
| dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect); |
| |
| /* Read in .dynamic section, silently ignore errors. */ |
| dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect); |
| buf = alloca (dyninfo_sect_size); |
| if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size)) |
| return 0; |
| |
| /* Find the DT_DEBUG entry in the the .dynamic section. |
| For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has |
| no DT_DEBUG entries. */ |
| #ifndef TARGET_ELF64 |
| for (bufend = buf + dyninfo_sect_size; |
| buf < bufend; |
| buf += sizeof (Elf32_External_Dyn)) |
| { |
| Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *) buf; |
| long dyn_tag; |
| CORE_ADDR dyn_ptr; |
| |
| dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag); |
| if (dyn_tag == DT_NULL) |
| break; |
| else if (dyn_tag == DT_DEBUG) |
| { |
| dyn_ptr = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_un.d_ptr); |
| return dyn_ptr; |
| } |
| #ifdef DT_MIPS_RLD_MAP |
| else if (dyn_tag == DT_MIPS_RLD_MAP) |
| { |
| char pbuf[TARGET_PTR_BIT / HOST_CHAR_BIT]; |
| |
| /* DT_MIPS_RLD_MAP contains a pointer to the address |
| of the dynamic link structure. */ |
| dyn_ptr = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_un.d_ptr); |
| if (target_read_memory (dyn_ptr, pbuf, sizeof (pbuf))) |
| return 0; |
| return extract_unsigned_integer (pbuf, sizeof (pbuf)); |
| } |
| #endif |
| } |
| #else /* ELF64 */ |
| for (bufend = buf + dyninfo_sect_size; |
| buf < bufend; |
| buf += sizeof (Elf64_External_Dyn)) |
| { |
| Elf64_External_Dyn *x_dynp = (Elf64_External_Dyn *) buf; |
| long dyn_tag; |
| CORE_ADDR dyn_ptr; |
| |
| dyn_tag = bfd_h_get_64 (exec_bfd, (bfd_byte *) x_dynp->d_tag); |
| if (dyn_tag == DT_NULL) |
| break; |
| else if (dyn_tag == DT_DEBUG) |
| { |
| dyn_ptr = bfd_h_get_64 (exec_bfd, (bfd_byte *) x_dynp->d_un.d_ptr); |
| return dyn_ptr; |
| } |
| } |
| #endif |
| |
| /* DT_DEBUG entry not found. */ |
| return 0; |
| } |
| |
| #endif /* SVR4_SHARED_LIBS */ |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| locate_base -- locate the base address of dynamic linker structs |
| |
| SYNOPSIS |
| |
| CORE_ADDR locate_base (void) |
| |
| DESCRIPTION |
| |
| 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 () |
| { |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| struct minimal_symbol *msymbol; |
| CORE_ADDR address = 0; |
| char **symbolp; |
| |
| /* For SunOS, we want to limit the search for the debug base symbol to the |
| executable being debugged, since there is a duplicate named symbol in the |
| shared library. We don't want the shared library versions. */ |
| |
| for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++) |
| { |
| msymbol = lookup_minimal_symbol (*symbolp, NULL, symfile_objfile); |
| if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| { |
| address = SYMBOL_VALUE_ADDRESS (msymbol); |
| return (address); |
| } |
| } |
| return (0); |
| |
| #else /* SVR4_SHARED_LIBS */ |
| |
| /* 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. */ |
| |
| if (debug_base == 0) |
| { |
| if (exec_bfd != NULL |
| && bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour) |
| debug_base = elf_locate_base (); |
| #ifdef HANDLE_SVR4_EXEC_EMULATORS |
| /* Try it the hard way for emulated executables. */ |
| else if (inferior_pid != 0 && target_has_execution) |
| proc_iterate_over_mappings (look_for_base); |
| #endif |
| } |
| return (debug_base); |
| |
| #endif /* !SVR4_SHARED_LIBS */ |
| |
| } |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| first_link_map_member -- locate first member in dynamic linker's map |
| |
| SYNOPSIS |
| |
| static struct link_map *first_link_map_member (void) |
| |
| DESCRIPTION |
| |
| Read in a copy of the first member in the inferior's dynamic |
| link map from the inferior's dynamic linker structures, and return |
| a pointer to the copy in our address space. |
| */ |
| |
| static struct link_map * |
| first_link_map_member () |
| { |
| struct link_map *lm = NULL; |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| read_memory (debug_base, (char *) &dynamic_copy, sizeof (dynamic_copy)); |
| if (dynamic_copy.ld_version >= 2) |
| { |
| /* It is a version that we can deal with, so read in the secondary |
| structure and find the address of the link map list from it. */ |
| read_memory ((CORE_ADDR) dynamic_copy.ld_un.ld_2, (char *) &ld_2_copy, |
| sizeof (struct link_dynamic_2)); |
| lm = ld_2_copy.ld_loaded; |
| } |
| |
| #else /* SVR4_SHARED_LIBS */ |
| |
| read_memory (debug_base, (char *) &debug_copy, sizeof (struct r_debug)); |
| /* FIXME: Perhaps we should validate the info somehow, perhaps by |
| checking r_version for a known version number, or r_state for |
| RT_CONSISTENT. */ |
| lm = debug_copy.r_map; |
| |
| #endif /* !SVR4_SHARED_LIBS */ |
| |
| return (lm); |
| } |
| |
| #ifdef SVR4_SHARED_LIBS |
| /* |
| |
| LOCAL FUNCTION |
| |
| open_exec_file_object |
| |
| SYNOPSIS |
| |
| void open_symbol_file_object (int from_tty) |
| |
| DESCRIPTION |
| |
| 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. |
| |
| */ |
| |
| int |
| open_symbol_file_object (arg) |
| PTR arg; |
| { |
| int from_tty = (int) arg; /* sneak past catch_errors */ |
| struct link_map *lm, lmcopy; |
| char *filename; |
| int errcode; |
| |
| if (symfile_objfile) |
| if (!query ("Attempt to reload symbols from process? ")) |
| return 0; |
| |
| if ((debug_base = locate_base ()) == 0) |
| return 0; /* failed somehow... */ |
| |
| /* First link map member should be the executable. */ |
| if ((lm = first_link_map_member ()) == NULL) |
| return 0; /* failed somehow... */ |
| |
| /* Read from target memory to GDB. */ |
| read_memory ((CORE_ADDR) lm, (void *) &lmcopy, sizeof (lmcopy)); |
| |
| if (lmcopy.l_name == 0) |
| return 0; /* no filename. */ |
| |
| /* Now fetch the filename from target memory. */ |
| target_read_string ((CORE_ADDR) lmcopy.l_name, &filename, |
| MAX_PATH_SIZE - 1, &errcode); |
| if (errcode) |
| { |
| warning ("failed to read exec filename from attached file: %s", |
| safe_strerror (errcode)); |
| return 0; |
| } |
| |
| make_cleanup ((make_cleanup_func) free, (void *) filename); |
| /* Have a pathname: read the symbol file. */ |
| symbol_file_command (filename, from_tty); |
| |
| return 1; |
| } |
| #endif /* SVR4_SHARED_LIBS */ |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| find_solib -- step through list of shared objects |
| |
| SYNOPSIS |
| |
| struct so_list *find_solib (struct so_list *so_list_ptr) |
| |
| DESCRIPTION |
| |
| This module contains the routine which finds the names of any |
| loaded "images" in the current process. The argument in must be |
| NULL on the first call, and then the returned value must be passed |
| in on subsequent calls. This provides the capability to "step" down |
| the list of loaded objects. On the last object, a NULL value is |
| returned. |
| |
| The arg and return value are "struct link_map" pointers, as defined |
| in <link.h>. |
| */ |
| |
| static struct so_list * |
| find_solib (so_list_ptr) |
| struct so_list *so_list_ptr; /* Last lm or NULL for first one */ |
| { |
| struct so_list *so_list_next = NULL; |
| struct link_map *lm = NULL; |
| struct so_list *new; |
| |
| if (so_list_ptr == NULL) |
| { |
| /* We are setting up for a new scan through the loaded images. */ |
| if ((so_list_next = so_list_head) == NULL) |
| { |
| /* We have not already read in the dynamic linking structures |
| from the inferior, lookup the address of the base structure. */ |
| debug_base = locate_base (); |
| if (debug_base != 0) |
| { |
| /* Read the base structure in and find the address of the first |
| link map list member. */ |
| lm = first_link_map_member (); |
| } |
| } |
| } |
| else |
| { |
| /* We have been called before, and are in the process of walking |
| the shared library list. Advance to the next shared object. */ |
| if ((lm = LM_NEXT (so_list_ptr)) == NULL) |
| { |
| /* We have hit the end of the list, so check to see if any were |
| added, but be quiet if we can't read from the target any more. */ |
| int status = target_read_memory ((CORE_ADDR) so_list_ptr->lmaddr, |
| (char *) &(so_list_ptr->lm), |
| sizeof (struct link_map)); |
| if (status == 0) |
| { |
| lm = LM_NEXT (so_list_ptr); |
| } |
| else |
| { |
| lm = NULL; |
| } |
| } |
| so_list_next = so_list_ptr->next; |
| } |
| if ((so_list_next == NULL) && (lm != NULL)) |
| { |
| /* Get next link map structure from inferior image and build a local |
| abbreviated load_map structure */ |
| new = (struct so_list *) xmalloc (sizeof (struct so_list)); |
| memset ((char *) new, 0, sizeof (struct so_list)); |
| new->lmaddr = lm; |
| /* Add the new node as the next node in the list, or as the root |
| node if this is the first one. */ |
| if (so_list_ptr != NULL) |
| { |
| so_list_ptr->next = new; |
| } |
| else |
| { |
| so_list_head = new; |
| |
| if (!solib_cleanup_queued) |
| { |
| make_run_cleanup (do_clear_solib, NULL); |
| solib_cleanup_queued = 1; |
| } |
| |
| } |
| so_list_next = new; |
| read_memory ((CORE_ADDR) lm, (char *) &(new->lm), |
| sizeof (struct link_map)); |
| /* 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_LINK_MAP_ENTRY (new->lm)) |
| { |
| int errcode; |
| char *buffer; |
| target_read_string ((CORE_ADDR) LM_NAME (new), &buffer, |
| MAX_PATH_SIZE - 1, &errcode); |
| if (errcode != 0) |
| { |
| warning ("find_solib: Can't read pathname for load map: %s\n", |
| safe_strerror (errcode)); |
| return (so_list_next); |
| } |
| strncpy (new->so_name, buffer, MAX_PATH_SIZE - 1); |
| new->so_name[MAX_PATH_SIZE - 1] = '\0'; |
| free (buffer); |
| catch_errors (solib_map_sections, new, |
| "Error while mapping shared library sections:\n", |
| RETURN_MASK_ALL); |
| } |
| } |
| return (so_list_next); |
| } |
| |
| /* A small stub to get us past the arg-passing pinhole of catch_errors. */ |
| |
| static int |
| symbol_add_stub (arg) |
| PTR arg; |
| { |
| register struct so_list *so = (struct so_list *) arg; /* catch_errs bogon */ |
| CORE_ADDR text_addr = 0; |
| struct section_addr_info section_addrs; |
| |
| memset (§ion_addrs, 0, sizeof (section_addrs)); |
| if (so->textsection) |
| text_addr = so->textsection->addr; |
| else if (so->abfd != NULL) |
| { |
| asection *lowest_sect; |
| |
| /* If we didn't find a mapped non zero sized .text section, set up |
| text_addr so that the relocation in symbol_file_add does no harm. */ |
| |
| lowest_sect = bfd_get_section_by_name (so->abfd, ".text"); |
| if (lowest_sect == NULL) |
| bfd_map_over_sections (so->abfd, find_lowest_section, |
| (PTR) &lowest_sect); |
| if (lowest_sect) |
| text_addr = bfd_section_vma (so->abfd, lowest_sect) |
| + (CORE_ADDR) LM_ADDR (so); |
| } |
| |
| ALL_OBJFILES (so->objfile) |
| { |
| if (strcmp (so->objfile->name, so->so_name) == 0) |
| return 1; |
| } |
| section_addrs.text_addr = text_addr; |
| so->objfile = |
| symbol_file_add (so->so_name, so->from_tty, |
| §ion_addrs, 0, OBJF_SHARED); |
| return (1); |
| } |
| |
| /* This function will check the so name to see if matches the main list. |
| In some system the main object is in the list, which we want to exclude */ |
| |
| static int |
| match_main (soname) |
| char *soname; |
| { |
| char **mainp; |
| |
| for (mainp = main_name_list; *mainp != NULL; mainp++) |
| { |
| if (strcmp (soname, *mainp) == 0) |
| return (1); |
| } |
| |
| return (0); |
| } |
| |
| /* |
| |
| GLOBAL FUNCTION |
| |
| solib_add -- add a shared library file to the symtab and section list |
| |
| SYNOPSIS |
| |
| void solib_add (char *arg_string, int from_tty, |
| struct target_ops *target) |
| |
| DESCRIPTION |
| |
| */ |
| |
| void |
| solib_add (arg_string, from_tty, target) |
| char *arg_string; |
| int from_tty; |
| struct target_ops *target; |
| { |
| register struct so_list *so = NULL; /* link map state variable */ |
| |
| /* Last shared library that we read. */ |
| struct so_list *so_last = NULL; |
| |
| char *re_err; |
| int count; |
| int old; |
| |
| #ifdef SVR4_SHARED_LIBS |
| /* If we are attaching to a running process for which we |
| have not opened a symbol file, we may be able to get its |
| symbols now! */ |
| if (attach_flag && |
| symfile_objfile == NULL) |
| catch_errors (open_symbol_file_object, (PTR) from_tty, |
| "Error reading attached process's symbol file.\n", |
| RETURN_MASK_ALL); |
| |
| #endif SVR4_SHARED_LIBS |
| |
| if ((re_err = re_comp (arg_string? arg_string : ".")) != NULL) |
| { |
| error ("Invalid regexp: %s", re_err); |
| } |
| |
| /* Add the shared library sections to the section table of the |
| specified target, if any. */ |
| if (target) |
| { |
| /* Count how many new section_table entries there are. */ |
| so = NULL; |
| count = 0; |
| while ((so = find_solib (so)) != NULL) |
| { |
| if (so->so_name[0] && !match_main (so->so_name)) |
| { |
| count += so->sections_end - so->sections; |
| } |
| } |
| |
| if (count) |
| { |
| |
| /* Add these section table entries to the target's table. */ |
| old = target_resize_to_sections (target, count); |
| while ((so = find_solib (so)) != NULL) |
| { |
| if (so->so_name[0]) |
| { |
| count = so->sections_end - so->sections; |
| memcpy ((char *) (target->to_sections + old), |
| so->sections, |
| (sizeof (struct section_table)) * count); |
| old += count; |
| } |
| } |
| } |
| } |
| |
| /* Now add the symbol files. */ |
| while ((so = find_solib (so)) != NULL) |
| { |
| if (so->so_name[0] && re_exec (so->so_name) && |
| !match_main (so->so_name)) |
| { |
| so->from_tty = from_tty; |
| if (so->symbols_loaded) |
| { |
| if (from_tty) |
| { |
| printf_unfiltered ("Symbols already loaded for %s\n", so->so_name); |
| } |
| } |
| else if (catch_errors |
| (symbol_add_stub, so, |
| "Error while reading shared library symbols:\n", |
| RETURN_MASK_ALL)) |
| { |
| so_last = so; |
| so->symbols_loaded = 1; |
| } |
| } |
| } |
| |
| /* Getting new symbols may change our opinion about what is |
| frameless. */ |
| if (so_last) |
| reinit_frame_cache (); |
| |
| if (so_last) |
| special_symbol_handling (so_last); |
| } |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| info_sharedlibrary_command -- code for "info sharedlibrary" |
| |
| SYNOPSIS |
| |
| static void info_sharedlibrary_command () |
| |
| DESCRIPTION |
| |
| Walk through the shared library list and print information |
| about each attached library. |
| */ |
| |
| static void |
| info_sharedlibrary_command (ignore, from_tty) |
| char *ignore; |
| int from_tty; |
| { |
| register struct so_list *so = NULL; /* link map state variable */ |
| int header_done = 0; |
| int addr_width; |
| char *addr_fmt; |
| |
| if (exec_bfd == NULL) |
| { |
| printf_unfiltered ("No executable file.\n"); |
| return; |
| } |
| |
| #ifndef TARGET_ELF64 |
| addr_width = 8 + 4; |
| addr_fmt = "08l"; |
| #else |
| addr_width = 16 + 4; |
| addr_fmt = "016l"; |
| #endif |
| |
| while ((so = find_solib (so)) != NULL) |
| { |
| if (so->so_name[0]) |
| { |
| if (!header_done) |
| { |
| printf_unfiltered ("%-*s%-*s%-12s%s\n", addr_width, "From", |
| addr_width, "To", "Syms Read", |
| "Shared Object Library"); |
| header_done++; |
| } |
| |
| printf_unfiltered ("%-*s", addr_width, |
| local_hex_string_custom ((unsigned long) LM_ADDR (so), |
| addr_fmt)); |
| printf_unfiltered ("%-*s", addr_width, |
| local_hex_string_custom ((unsigned long) so->lmend, |
| addr_fmt)); |
| printf_unfiltered ("%-12s", so->symbols_loaded ? "Yes" : "No"); |
| printf_unfiltered ("%s\n", so->so_name); |
| } |
| } |
| if (so_list_head == NULL) |
| { |
| printf_unfiltered ("No shared libraries loaded at this time.\n"); |
| } |
| } |
| |
| /* |
| |
| GLOBAL FUNCTION |
| |
| solib_address -- check to see if an address is in a shared lib |
| |
| SYNOPSIS |
| |
| char * solib_address (CORE_ADDR address) |
| |
| DESCRIPTION |
| |
| Provides a hook for other gdb routines to discover whether or |
| not a particular address is within the mapped address space of |
| a shared library. Any address between the base mapping address |
| and the first address beyond the end of the last mapping, is |
| considered to be within the shared library address space, for |
| our purposes. |
| |
| For example, this routine is called at one point to disable |
| breakpoints which are in shared libraries that are not currently |
| mapped in. |
| */ |
| |
| char * |
| solib_address (address) |
| CORE_ADDR address; |
| { |
| register struct so_list *so = 0; /* link map state variable */ |
| |
| while ((so = find_solib (so)) != NULL) |
| { |
| if (so->so_name[0]) |
| { |
| if ((address >= (CORE_ADDR) LM_ADDR (so)) && |
| (address < (CORE_ADDR) so->lmend)) |
| return (so->so_name); |
| } |
| } |
| return (0); |
| } |
| |
| /* Called by free_all_symtabs */ |
| |
| void |
| clear_solib () |
| { |
| struct so_list *next; |
| char *bfd_filename; |
| |
| /* This function is expected to handle ELF shared libraries. It is |
| also used on Solaris, which can run either ELF or a.out binaries |
| (for compatibility with SunOS 4), both of which can use shared |
| libraries. So we don't know whether we have an ELF executable or |
| an a.out executable until the user chooses an executable file. |
| |
| ELF shared libraries don't get mapped into the address space |
| until after the program starts, so we'd better not try to insert |
| breakpoints in them immediately. We have to wait until the |
| dynamic linker has loaded them; we'll hit a bp_shlib_event |
| breakpoint (look for calls to create_solib_event_breakpoint) when |
| it's ready. |
| |
| SunOS shared libraries seem to be different --- they're present |
| as soon as the process begins execution, so there's no need to |
| put off inserting breakpoints. There's also nowhere to put a |
| bp_shlib_event breakpoint, so if we put it off, we'll never get |
| around to it. |
| |
| So: disable breakpoints only if we're using ELF shared libs. */ |
| if (exec_bfd != NULL |
| && bfd_get_flavour (exec_bfd) != bfd_target_aout_flavour) |
| disable_breakpoints_in_shlibs (1); |
| |
| while (so_list_head) |
| { |
| if (so_list_head->sections) |
| { |
| free ((PTR) so_list_head->sections); |
| } |
| if (so_list_head->abfd) |
| { |
| bfd_filename = bfd_get_filename (so_list_head->abfd); |
| if (!bfd_close (so_list_head->abfd)) |
| warning ("cannot close \"%s\": %s", |
| bfd_filename, bfd_errmsg (bfd_get_error ())); |
| } |
| else |
| /* This happens for the executable on SVR4. */ |
| bfd_filename = NULL; |
| |
| next = so_list_head->next; |
| if (bfd_filename) |
| free ((PTR) bfd_filename); |
| free ((PTR) so_list_head); |
| so_list_head = next; |
| } |
| debug_base = 0; |
| } |
| |
| static void |
| do_clear_solib (dummy) |
| PTR dummy; |
| { |
| solib_cleanup_queued = 0; |
| clear_solib (); |
| } |
| |
| #ifdef SVR4_SHARED_LIBS |
| |
| /* Return 1 if PC lies in the dynamic symbol resolution code of the |
| SVR4 run time loader. */ |
| |
| static CORE_ADDR interp_text_sect_low; |
| static CORE_ADDR interp_text_sect_high; |
| static CORE_ADDR interp_plt_sect_low; |
| static CORE_ADDR interp_plt_sect_high; |
| |
| int |
| in_svr4_dynsym_resolve_code (pc) |
| CORE_ADDR pc; |
| { |
| return ((pc >= interp_text_sect_low && pc < interp_text_sect_high) |
| || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high) |
| || in_plt_section (pc, NULL)); |
| } |
| #endif |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| disable_break -- remove the "mapping changed" breakpoint |
| |
| SYNOPSIS |
| |
| static int disable_break () |
| |
| DESCRIPTION |
| |
| Removes the breakpoint that gets hit when the dynamic linker |
| completes a mapping change. |
| |
| */ |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| static int |
| disable_break () |
| { |
| int status = 1; |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| int in_debugger = 0; |
| |
| /* Read the debugger structure from the inferior to retrieve the |
| address of the breakpoint and the original contents of the |
| breakpoint address. Remove the breakpoint by writing the original |
| contents back. */ |
| |
| read_memory (debug_addr, (char *) &debug_copy, sizeof (debug_copy)); |
| |
| /* Set `in_debugger' to zero now. */ |
| |
| write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger)); |
| |
| breakpoint_addr = (CORE_ADDR) debug_copy.ldd_bp_addr; |
| write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst, |
| sizeof (debug_copy.ldd_bp_inst)); |
| |
| #else /* SVR4_SHARED_LIBS */ |
| |
| /* Note that breakpoint address and original contents are in our address |
| space, so we just need to write the original contents back. */ |
| |
| if (memory_remove_breakpoint (breakpoint_addr, shadow_contents) != 0) |
| { |
| status = 0; |
| } |
| |
| #endif /* !SVR4_SHARED_LIBS */ |
| |
| /* For the SVR4 version, we always know the breakpoint address. For the |
| SunOS version we don't know it until the above code is executed. |
| Grumble if we are stopped anywhere besides the breakpoint address. */ |
| |
| if (stop_pc != breakpoint_addr) |
| { |
| warning ("stopped at unknown breakpoint while handling shared libraries"); |
| } |
| |
| return (status); |
| } |
| |
| #endif /* #ifdef SVR4_SHARED_LIBS */ |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| enable_break -- arrange for dynamic linker to hit breakpoint |
| |
| SYNOPSIS |
| |
| int enable_break (void) |
| |
| DESCRIPTION |
| |
| 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 () |
| { |
| int success = 0; |
| |
| #ifndef SVR4_SHARED_LIBS |
| |
| int j; |
| int in_debugger; |
| |
| /* Get link_dynamic structure */ |
| |
| j = target_read_memory (debug_base, (char *) &dynamic_copy, |
| sizeof (dynamic_copy)); |
| if (j) |
| { |
| /* unreadable */ |
| return (0); |
| } |
| |
| /* Calc address of debugger interface structure */ |
| |
| debug_addr = (CORE_ADDR) dynamic_copy.ldd; |
| |
| /* Calc address of `in_debugger' member of debugger interface structure */ |
| |
| flag_addr = debug_addr + (CORE_ADDR) ((char *) &debug_copy.ldd_in_debugger - |
| (char *) &debug_copy); |
| |
| /* Write a value of 1 to this member. */ |
| |
| in_debugger = 1; |
| write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger)); |
| success = 1; |
| |
| #else /* SVR4_SHARED_LIBS */ |
| |
| #ifdef BKPT_AT_SYMBOL |
| |
| struct minimal_symbol *msymbol; |
| char **bkpt_namep; |
| asection *interp_sect; |
| |
| /* First, remove all the solib event breakpoints. Their addresses |
| may have changed since the last time we ran the program. */ |
| remove_solib_event_breakpoints (); |
| |
| #ifdef SVR4_SHARED_LIBS |
| interp_text_sect_low = interp_text_sect_high = 0; |
| interp_plt_sect_low = interp_plt_sect_high = 0; |
| |
| /* Find the .interp section; if not found, warn the user and drop |
| into the old breakpoint at symbol code. */ |
| interp_sect = bfd_get_section_by_name (exec_bfd, ".interp"); |
| if (interp_sect) |
| { |
| unsigned int interp_sect_size; |
| char *buf; |
| CORE_ADDR load_addr; |
| bfd *tmp_bfd; |
| CORE_ADDR sym_addr = 0; |
| |
| /* Read the contents of the .interp section into a local buffer; |
| the contents specify the dynamic linker this program uses. */ |
| interp_sect_size = bfd_section_size (exec_bfd, interp_sect); |
| buf = alloca (interp_sect_size); |
| bfd_get_section_contents (exec_bfd, interp_sect, |
| buf, 0, interp_sect_size); |
| |
| /* 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. */ |
| tmp_bfd = bfd_openr (buf, gnutarget); |
| if (tmp_bfd == NULL) |
| goto bkpt_at_symbol; |
| |
| /* Make sure the dynamic linker's really a useful object. */ |
| if (!bfd_check_format (tmp_bfd, bfd_object)) |
| { |
| warning ("Unable to grok dynamic linker %s as an object file", buf); |
| bfd_close (tmp_bfd); |
| goto bkpt_at_symbol; |
| } |
| |
| /* We find the dynamic linker's base address by examining the |
| current pc (which point at the entry point for the dynamic |
| linker) and subtracting the offset of the entry point. */ |
| load_addr = read_pc () - tmp_bfd->start_address; |
| |
| /* Record the relocated start and end address of the dynamic linker |
| text and plt section for in_svr4_dynsym_resolve_code. */ |
| interp_sect = bfd_get_section_by_name (tmp_bfd, ".text"); |
| if (interp_sect) |
| { |
| interp_text_sect_low = |
| bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| interp_text_sect_high = |
| interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect); |
| } |
| interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt"); |
| if (interp_sect) |
| { |
| interp_plt_sect_low = |
| bfd_section_vma (tmp_bfd, interp_sect) + load_addr; |
| interp_plt_sect_high = |
| 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 = bfd_lookup_symbol (tmp_bfd, *bkpt_namep); |
| if (sym_addr != 0) |
| break; |
| } |
| |
| /* We're done with the temporary bfd. */ |
| bfd_close (tmp_bfd); |
| |
| if (sym_addr != 0) |
| { |
| create_solib_event_breakpoint (load_addr + sym_addr); |
| 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: |
| warning ("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code."); |
| } |
| #endif |
| |
| /* Scan through the list of symbols, trying to look up the symbol and |
| set a breakpoint there. Terminate loop when we/if we succeed. */ |
| |
| breakpoint_addr = 0; |
| for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++) |
| { |
| msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile); |
| if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0)) |
| { |
| create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol)); |
| return 1; |
| } |
| } |
| |
| /* Nothing good happened. */ |
| success = 0; |
| |
| #endif /* BKPT_AT_SYMBOL */ |
| |
| #endif /* !SVR4_SHARED_LIBS */ |
| |
| return (success); |
| } |
| |
| /* |
| |
| GLOBAL FUNCTION |
| |
| solib_create_inferior_hook -- shared library startup support |
| |
| SYNOPSIS |
| |
| void solib_create_inferior_hook() |
| |
| DESCRIPTION |
| |
| When gdb starts up the inferior, it nurses it along (through the |
| shell) until it is ready to execute it's first instruction. At this |
| point, this function gets called via expansion of the macro |
| SOLIB_CREATE_INFERIOR_HOOK. |
| |
| For SunOS executables, this first instruction is typically the |
| one at "_start", or a similar text label, regardless of whether |
| the executable is statically or dynamically linked. The runtime |
| startup code takes care of dynamically linking in any shared |
| libraries, once gdb allows the inferior to continue. |
| |
| 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. |
| |
| For both SunOS shared libraries, and SVR4 shared libraries, 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. |
| |
| FIXME |
| |
| Between enable_break() and disable_break(), this code does not |
| properly handle hitting breakpoints which the user might have |
| set in the startup code or in the dynamic linker itself. Proper |
| handling will probably have to wait until the implementation is |
| changed to use the "breakpoint handler function" method. |
| |
| Also, what if child has exit()ed? Must exit loop somehow. |
| */ |
| |
| void |
| solib_create_inferior_hook () |
| { |
| /* If we are using the BKPT_AT_SYMBOL code, then we don't need the base |
| yet. In fact, in the case of a SunOS4 executable being run on |
| Solaris, we can't get it yet. find_solib will get it when it needs |
| it. */ |
| #if !(defined (SVR4_SHARED_LIBS) && defined (BKPT_AT_SYMBOL)) |
| if ((debug_base = locate_base ()) == 0) |
| { |
| /* Can't find the symbol or the executable is statically linked. */ |
| return; |
| } |
| #endif |
| |
| if (!enable_break ()) |
| { |
| warning ("shared library handler failed to enable breakpoint"); |
| return; |
| } |
| |
| #if !defined(SVR4_SHARED_LIBS) || defined(_SCO_DS) |
| /* SCO and SunOS need the loop below, other systems should be using the |
| special shared library breakpoints and the shared library breakpoint |
| service routine. |
| |
| Now run the target. It will eventually hit the breakpoint, at |
| which point all of the libraries will have been mapped in and we |
| can go groveling around in the dynamic linker structures to find |
| out what we need to know about them. */ |
| |
| clear_proceed_status (); |
| stop_soon_quietly = 1; |
| stop_signal = TARGET_SIGNAL_0; |
| do |
| { |
| target_resume (-1, 0, stop_signal); |
| wait_for_inferior (); |
| } |
| while (stop_signal != TARGET_SIGNAL_TRAP); |
| stop_soon_quietly = 0; |
| |
| #if !defined(_SCO_DS) |
| /* We are now either at the "mapping complete" breakpoint (or somewhere |
| else, a condition we aren't prepared to deal with anyway), so adjust |
| the PC as necessary after a breakpoint, disable the breakpoint, and |
| add any shared libraries that were mapped in. */ |
| |
| if (DECR_PC_AFTER_BREAK) |
| { |
| stop_pc -= DECR_PC_AFTER_BREAK; |
| write_register (PC_REGNUM, stop_pc); |
| } |
| |
| if (!disable_break ()) |
| { |
| warning ("shared library handler failed to disable breakpoint"); |
| } |
| |
| if (auto_solib_add) |
| solib_add ((char *) 0, 0, (struct target_ops *) 0); |
| #endif /* ! _SCO_DS */ |
| #endif |
| } |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| special_symbol_handling -- additional shared library symbol handling |
| |
| SYNOPSIS |
| |
| void special_symbol_handling (struct so_list *so) |
| |
| DESCRIPTION |
| |
| Once the symbols from a shared object have been loaded in the usual |
| way, we are called to do any system specific symbol handling that |
| is needed. |
| |
| For SunOS4, this consists of grunging around in the dynamic |
| linkers structures to find symbol definitions for "common" symbols |
| and adding them to the minimal symbol table for the runtime common |
| objfile. |
| |
| */ |
| |
| static void |
| special_symbol_handling (so) |
| struct so_list *so; |
| { |
| #ifndef SVR4_SHARED_LIBS |
| int j; |
| |
| if (debug_addr == 0) |
| { |
| /* Get link_dynamic structure */ |
| |
| j = target_read_memory (debug_base, (char *) &dynamic_copy, |
| sizeof (dynamic_copy)); |
| if (j) |
| { |
| /* unreadable */ |
| return; |
| } |
| |
| /* Calc address of debugger interface structure */ |
| /* FIXME, this needs work for cross-debugging of core files |
| (byteorder, size, alignment, etc). */ |
| |
| debug_addr = (CORE_ADDR) dynamic_copy.ldd; |
| } |
| |
| /* Read the debugger structure from the inferior, just to make sure |
| we have a current copy. */ |
| |
| j = target_read_memory (debug_addr, (char *) &debug_copy, |
| sizeof (debug_copy)); |
| if (j) |
| return; /* unreadable */ |
| |
| /* Get common symbol definitions for the loaded object. */ |
| |
| if (debug_copy.ldd_cp) |
| { |
| solib_add_common_symbols (debug_copy.ldd_cp); |
| } |
| |
| #endif /* !SVR4_SHARED_LIBS */ |
| } |
| |
| |
| /* |
| |
| LOCAL FUNCTION |
| |
| sharedlibrary_command -- handle command to explicitly add library |
| |
| SYNOPSIS |
| |
| static void sharedlibrary_command (char *args, int from_tty) |
| |
| DESCRIPTION |
| |
| */ |
| |
| static void |
| sharedlibrary_command (args, from_tty) |
| char *args; |
| int from_tty; |
| { |
| dont_repeat (); |
| solib_add (args, from_tty, (struct target_ops *) 0); |
| } |
| |
| #endif /* HAVE_LINK_H */ |
| |
| void |
| _initialize_solib () |
| { |
| #ifdef HAVE_LINK_H |
| |
| add_com ("sharedlibrary", class_files, sharedlibrary_command, |
| "Load shared object library symbols for files matching REGEXP."); |
| add_info ("sharedlibrary", info_sharedlibrary_command, |
| "Status of loaded shared object libraries."); |
| |
| add_show_from_set |
| (add_set_cmd ("auto-solib-add", class_support, var_zinteger, |
| (char *) &auto_solib_add, |
| "Set autoloading of shared library symbols.\n\ |
| If nonzero, symbols from all shared object libraries will be loaded\n\ |
| automatically when the inferior begins execution or when the dynamic linker\n\ |
| informs gdb that a new library has been loaded. Otherwise, symbols\n\ |
| must be loaded manually, using `sharedlibrary'.", |
| &setlist), |
| &showlist); |
| |
| add_show_from_set |
| (add_set_cmd ("solib-absolute-prefix", class_support, var_filename, |
| (char *) &solib_absolute_prefix, |
| "Set prefix for loading absolute shared library symbol files.\n\ |
| For other (relative) files, you can add values using `set solib-search-path'.", |
| &setlist), |
| &showlist); |
| add_show_from_set |
| (add_set_cmd ("solib-search-path", class_support, var_string, |
| (char *) &solib_search_path, |
| "Set the search path for loading non-absolute shared library symbol files.\n\ |
| This takes precedence over the environment variables PATH and LD_LIBRARY_PATH.", |
| &setlist), |
| &showlist); |
| |
| #endif /* HAVE_LINK_H */ |
| } |