yann@96: Status: submitted for comments yann@96: yann@96: 2004-11-12 Daniel Jacobowitz yann@96: yann@96: * linux-nat.c (my_waitpid): New function. yann@96: (linux_test_for_tracefork): Make more robust and verbose. Take yann@96: an ORIGINAL_PID argument and test for PTRACE_SETOPTIONS first. yann@96: (linux_supports_tracefork, linux_supports_tracevforkdone): Take a PID yann@96: argument. Update calls to linux_test_for_tracefork. yann@96: (linux_enable_event_reporting, child_follow_fork) yann@96: (child_insert_fork_catchpoint, child_insert_vfork_catchpoint) yann@96: (child_insert_exec_catchpoint): Update calls to yann@96: linux_supports_tracefork and linux_supports_tracevforkdone. yann@96: yann@96: Index: gdb-6.3/gdb/linux-nat.c yann@96: =================================================================== yann@96: --- gdb-6.3.orig/gdb/linux-nat.c 2004-10-08 16:29:47.000000000 -0400 yann@96: +++ gdb-6.3/gdb/linux-nat.c 2004-11-13 16:41:51.368720845 -0500 yann@96: @@ -150,18 +150,47 @@ linux_tracefork_child (void) yann@96: exit (0); yann@96: } yann@96: yann@96: -/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. We yann@96: +/* Wrapper function for waitpid which handles EINTR. */ yann@96: + yann@96: +static int yann@96: +my_waitpid (int pid, int *status, int flags) yann@96: +{ yann@96: + int ret; yann@96: + do yann@96: + { yann@96: + ret = waitpid (pid, status, flags); yann@96: + } yann@96: + while (ret == -1 && errno == EINTR); yann@96: + yann@96: + return ret; yann@96: +} yann@96: + yann@96: +/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. yann@96: + yann@96: + First, we try to enable fork tracing on ORIGINAL_PID. If this fails, yann@96: + we know that the feature is not available. This may change the tracing yann@96: + options for ORIGINAL_PID, but we'll be setting them shortly anyway. yann@96: + yann@96: + However, if it succeeds, we don't know for sure that the feature is yann@96: + available; old versions of PTRACE_SETOPTIONS ignored unknown options. We yann@96: create a child process, attach to it, use PTRACE_SETOPTIONS to enable yann@96: - fork tracing, and let it fork. If the process exits, we assume that yann@96: - we can't use TRACEFORK; if we get the fork notification, and we can yann@96: - extract the new child's PID, then we assume that we can. */ yann@96: + fork tracing, and let it fork. If the process exits, we assume that we yann@96: + can't use TRACEFORK; if we get the fork notification, and we can extract yann@96: + the new child's PID, then we assume that we can. */ yann@96: yann@96: static void yann@96: -linux_test_for_tracefork (void) yann@96: +linux_test_for_tracefork (int original_pid) yann@96: { yann@96: int child_pid, ret, status; yann@96: long second_pid; yann@96: yann@96: + linux_supports_tracefork_flag = 0; yann@96: + linux_supports_tracevforkdone_flag = 0; yann@96: + yann@96: + ret = ptrace (PTRACE_SETOPTIONS, original_pid, 0, PTRACE_O_TRACEFORK); yann@96: + if (ret != 0) yann@96: + return; yann@96: + yann@96: child_pid = fork (); yann@96: if (child_pid == -1) yann@96: perror_with_name ("linux_test_for_tracefork: fork"); yann@96: @@ -169,7 +198,7 @@ linux_test_for_tracefork (void) yann@96: if (child_pid == 0) yann@96: linux_tracefork_child (); yann@96: yann@96: - ret = waitpid (child_pid, &status, 0); yann@96: + ret = my_waitpid (child_pid, &status, 0); yann@96: if (ret == -1) yann@96: perror_with_name ("linux_test_for_tracefork: waitpid"); yann@96: else if (ret != child_pid) yann@96: @@ -177,13 +206,23 @@ linux_test_for_tracefork (void) yann@96: if (! WIFSTOPPED (status)) yann@96: error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status); yann@96: yann@96: - linux_supports_tracefork_flag = 0; yann@96: - yann@96: ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK); yann@96: if (ret != 0) yann@96: { yann@96: - ptrace (PTRACE_KILL, child_pid, 0, 0); yann@96: - waitpid (child_pid, &status, 0); yann@96: + ret = ptrace (PTRACE_KILL, child_pid, 0, 0); yann@96: + if (ret != 0) yann@96: + { yann@96: + warning ("linux_test_for_tracefork: failed to kill child"); yann@96: + return; yann@96: + } yann@96: + yann@96: + ret = my_waitpid (child_pid, &status, 0); yann@96: + if (ret != child_pid) yann@96: + warning ("linux_test_for_tracefork: failed to wait for killed child"); yann@96: + else if (!WIFSIGNALED (status)) yann@96: + warning ("linux_test_for_tracefork: unexpected wait status 0x%x from " yann@96: + "killed child", status); yann@96: + yann@96: return; yann@96: } yann@96: yann@96: @@ -192,8 +231,12 @@ linux_test_for_tracefork (void) yann@96: PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORKDONE); yann@96: linux_supports_tracevforkdone_flag = (ret == 0); yann@96: yann@96: - ptrace (PTRACE_CONT, child_pid, 0, 0); yann@96: - ret = waitpid (child_pid, &status, 0); yann@96: + ret = ptrace (PTRACE_CONT, child_pid, 0, 0); yann@96: + if (ret != 0) yann@96: + warning ("linux_test_for_tracefork: failed to resume child"); yann@96: + yann@96: + ret = my_waitpid (child_pid, &status, 0); yann@96: + yann@96: if (ret == child_pid && WIFSTOPPED (status) yann@96: && status >> 16 == PTRACE_EVENT_FORK) yann@96: { yann@96: @@ -204,34 +247,38 @@ linux_test_for_tracefork (void) yann@96: int second_status; yann@96: yann@96: linux_supports_tracefork_flag = 1; yann@96: - waitpid (second_pid, &second_status, 0); yann@96: - ptrace (PTRACE_DETACH, second_pid, 0, 0); yann@96: + my_waitpid (second_pid, &second_status, 0); yann@96: + ret = ptrace (PTRACE_KILL, second_pid, 0, 0); yann@96: + if (ret != 0) yann@96: + warning ("linux_test_for_tracefork: failed to kill second child"); yann@96: } yann@96: } yann@96: + else yann@96: + warning ("linux_test_for_tracefork: unexpected result from waitpid " yann@96: + "(%d, status 0x%x)", ret, status); yann@96: yann@96: - if (WIFSTOPPED (status)) yann@96: - { yann@96: - ptrace (PTRACE_DETACH, child_pid, 0, 0); yann@96: - waitpid (child_pid, &status, 0); yann@96: - } yann@96: + ret = ptrace (PTRACE_KILL, child_pid, 0, 0); yann@96: + if (ret != 0) yann@96: + warning ("linux_test_for_tracefork: failed to kill child"); yann@96: + my_waitpid (child_pid, &status, 0); yann@96: } yann@96: yann@96: /* Return non-zero iff we have tracefork functionality available. yann@96: This function also sets linux_supports_tracefork_flag. */ yann@96: yann@96: static int yann@96: -linux_supports_tracefork (void) yann@96: +linux_supports_tracefork (int pid) yann@96: { yann@96: if (linux_supports_tracefork_flag == -1) yann@96: - linux_test_for_tracefork (); yann@96: + linux_test_for_tracefork (pid); yann@96: return linux_supports_tracefork_flag; yann@96: } yann@96: yann@96: static int yann@96: -linux_supports_tracevforkdone (void) yann@96: +linux_supports_tracevforkdone (int pid) yann@96: { yann@96: if (linux_supports_tracefork_flag == -1) yann@96: - linux_test_for_tracefork (); yann@96: + linux_test_for_tracefork (pid); yann@96: return linux_supports_tracevforkdone_flag; yann@96: } yann@96: yann@96: @@ -242,12 +289,12 @@ linux_enable_event_reporting (ptid_t pti yann@96: int pid = ptid_get_pid (ptid); yann@96: int options; yann@96: yann@96: - if (! linux_supports_tracefork ()) yann@96: + if (! linux_supports_tracefork (pid)) yann@96: return; yann@96: yann@96: options = PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK | PTRACE_O_TRACEEXEC yann@96: | PTRACE_O_TRACECLONE; yann@96: - if (linux_supports_tracevforkdone ()) yann@96: + if (linux_supports_tracevforkdone (pid)) yann@96: options |= PTRACE_O_TRACEVFORKDONE; yann@96: yann@96: /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support yann@96: @@ -308,7 +355,8 @@ child_follow_fork (int follow_child) yann@96: yann@96: if (has_vforked) yann@96: { yann@96: - if (linux_supports_tracevforkdone ()) yann@96: + gdb_assert (linux_supports_tracefork_flag >= 0); yann@96: + if (linux_supports_tracevforkdone (0)) yann@96: { yann@96: int status; yann@96: yann@96: @@ -476,7 +524,7 @@ linux_handle_extended_wait (int pid, int yann@96: int yann@96: child_insert_fork_catchpoint (int pid) yann@96: { yann@96: - if (! linux_supports_tracefork ()) yann@96: + if (! linux_supports_tracefork (pid)) yann@96: error ("Your system does not support fork catchpoints."); yann@96: yann@96: return 0; yann@96: @@ -485,7 +533,7 @@ child_insert_fork_catchpoint (int pid) yann@96: int yann@96: child_insert_vfork_catchpoint (int pid) yann@96: { yann@96: - if (!linux_supports_tracefork ()) yann@96: + if (!linux_supports_tracefork (pid)) yann@96: error ("Your system does not support vfork catchpoints."); yann@96: yann@96: return 0; yann@96: @@ -494,7 +542,7 @@ child_insert_vfork_catchpoint (int pid) yann@96: int yann@96: child_insert_exec_catchpoint (int pid) yann@96: { yann@96: - if (!linux_supports_tracefork ()) yann@96: + if (!linux_supports_tracefork (pid)) yann@96: error ("Your system does not support exec catchpoints."); yann@96: yann@96: return 0;