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b8aa79853d
openwrt/toolchain/gdb/patches/730-debian_gdb-fix-tracefork-check.patch
Felix Fietkau 60c1f0f64d finally move buildroot-ng to trunk
2016-03-20 17:29:15 +01:00

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