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Diffstat (limited to 'gdb/linux-nat.c')
| -rw-r--r-- | gdb/linux-nat.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c new file mode 100644 index 0000000..046544d --- /dev/null +++ b/gdb/linux-nat.c @@ -0,0 +1,176 @@ +/* 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> + +/* 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 + +/* 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; + + +/* 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."); +} + + |