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