| /* GNU/Linux native-dependent code common to multiple platforms. |
| Copyright (C) 2003 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" |
| #include "inferior.h" |
| #include "target.h" |
| |
| #include "gdb_wait.h" |
| #include <sys/ptrace.h> |
| |
| #include "linux-nat.h" |
| |
| /* If the system headers did not provide the constants, hard-code the normal |
| values. */ |
| #ifndef PTRACE_EVENT_FORK |
| |
| #define PTRACE_SETOPTIONS 0x4200 |
| #define PTRACE_GETEVENTMSG 0x4201 |
| |
| /* options set using PTRACE_SETOPTIONS */ |
| #define PTRACE_O_TRACESYSGOOD 0x00000001 |
| #define PTRACE_O_TRACEFORK 0x00000002 |
| #define PTRACE_O_TRACEVFORK 0x00000004 |
| #define PTRACE_O_TRACECLONE 0x00000008 |
| #define PTRACE_O_TRACEEXEC 0x00000010 |
| |
| /* Wait extended result codes for the above trace options. */ |
| #define PTRACE_EVENT_FORK 1 |
| #define PTRACE_EVENT_VFORK 2 |
| #define PTRACE_EVENT_CLONE 3 |
| #define PTRACE_EVENT_EXEC 4 |
| |
| #endif /* PTRACE_EVENT_FORK */ |
| |
| /* We can't always assume that this flag is available, but all systems |
| with the ptrace event handlers also have __WALL, so it's safe to use |
| here. */ |
| #ifndef __WALL |
| #define __WALL 0x40000000 /* Wait for any child. */ |
| #endif |
| |
| struct simple_pid_list |
| { |
| int pid; |
| struct simple_pid_list *next; |
| }; |
| struct simple_pid_list *stopped_pids; |
| |
| /* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK |
| can not be used, 1 if it can. */ |
| |
| static int linux_supports_tracefork_flag = -1; |
| |
| |
| /* Trivial list manipulation functions to keep track of a list of |
| new stopped processes. */ |
| static void |
| add_to_pid_list (struct simple_pid_list **listp, int pid) |
| { |
| struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list)); |
| new_pid->pid = pid; |
| new_pid->next = *listp; |
| *listp = new_pid; |
| } |
| |
| static int |
| pull_pid_from_list (struct simple_pid_list **listp, int pid) |
| { |
| struct simple_pid_list **p; |
| |
| for (p = listp; *p != NULL; p = &(*p)->next) |
| if ((*p)->pid == pid) |
| { |
| struct simple_pid_list *next = (*p)->next; |
| xfree (*p); |
| *p = next; |
| return 1; |
| } |
| return 0; |
| } |
| |
| void |
| linux_record_stopped_pid (int pid) |
| { |
| add_to_pid_list (&stopped_pids, pid); |
| } |
| |
| |
| /* A helper function for linux_test_for_tracefork, called after fork (). */ |
| |
| static void |
| linux_tracefork_child (void) |
| { |
| int ret; |
| |
| ptrace (PTRACE_TRACEME, 0, 0, 0); |
| kill (getpid (), SIGSTOP); |
| fork (); |
| exit (0); |
| } |
| |
| /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. We |
| create a child process, attach to it, use PTRACE_SETOPTIONS to enable |
| fork tracing, and let it fork. If the process exits, we assume that |
| we can't use TRACEFORK; if we get the fork notification, and we can |
| extract the new child's PID, then we assume that we can. */ |
| |
| static void |
| linux_test_for_tracefork (void) |
| { |
| int child_pid, ret, status; |
| long second_pid; |
| |
| child_pid = fork (); |
| if (child_pid == -1) |
| perror_with_name ("linux_test_for_tracefork: fork"); |
| |
| if (child_pid == 0) |
| linux_tracefork_child (); |
| |
| ret = waitpid (child_pid, &status, 0); |
| if (ret == -1) |
| perror_with_name ("linux_test_for_tracefork: waitpid"); |
| else if (ret != child_pid) |
| error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret); |
| if (! WIFSTOPPED (status)) |
| error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status); |
| |
| linux_supports_tracefork_flag = 0; |
| |
| ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK); |
| if (ret != 0) |
| { |
| ptrace (PTRACE_KILL, child_pid, 0, 0); |
| waitpid (child_pid, &status, 0); |
| return; |
| } |
| |
| ptrace (PTRACE_CONT, child_pid, 0, 0); |
| ret = waitpid (child_pid, &status, 0); |
| if (ret == child_pid && WIFSTOPPED (status) |
| && status >> 16 == PTRACE_EVENT_FORK) |
| { |
| second_pid = 0; |
| ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid); |
| if (ret == 0 && second_pid != 0) |
| { |
| int second_status; |
| |
| linux_supports_tracefork_flag = 1; |
| waitpid (second_pid, &second_status, 0); |
| ptrace (PTRACE_DETACH, second_pid, 0, 0); |
| } |
| } |
| |
| if (WIFSTOPPED (status)) |
| { |
| ptrace (PTRACE_DETACH, child_pid, 0, 0); |
| waitpid (child_pid, &status, 0); |
| } |
| } |
| |
| /* Return non-zero iff we have tracefork functionality available. |
| This function also sets linux_supports_tracefork_flag. */ |
| |
| static int |
| linux_supports_tracefork (void) |
| { |
| if (linux_supports_tracefork_flag == -1) |
| linux_test_for_tracefork (); |
| return linux_supports_tracefork_flag; |
| } |
| |
| |
| int |
| child_insert_fork_catchpoint (int pid) |
| { |
| if (linux_supports_tracefork ()) |
| error ("Fork catchpoints have not been implemented yet."); |
| else |
| error ("Your system does not support fork catchpoints."); |
| } |
| |
| int |
| child_insert_vfork_catchpoint (int pid) |
| { |
| if (linux_supports_tracefork ()) |
| error ("Vfork catchpoints have not been implemented yet."); |
| else |
| error ("Your system does not support vfork catchpoints."); |
| } |
| |
| int |
| child_insert_exec_catchpoint (int pid) |
| { |
| if (linux_supports_tracefork ()) |
| error ("Exec catchpoints have not been implemented yet."); |
| else |
| error ("Your system does not support exec catchpoints."); |
| } |
| |
| |