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authorTristan Gingold <tristan.gingold@adacore.com>2014-03-21 16:56:39 +0100
committerTristan Gingold <tristan.gingold@adacore.com>2014-04-01 11:50:36 +0200
commita41f2563d040d86954ccda7faa4a8ad7bdbcae88 (patch)
tree93fd71268e39dd41dfe6b583579d912b79b9c2b8 /gdb/darwin-nat.c
parent98d1b8dcd84bb39ba5d0731162f241890d4ce5f5 (diff)
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darwin-nat: avoid crash while debugging gdb.
it is possible that gdb gets mach exceptions from an unknown inferior. This happens when an inferior creates a child and that child gets a signal. So instead of reporting messages with unknown origins, simply reply to these notifications. The kernel will then post the unix signal. gdb/ * darwin-nat.c (darwin_encode_reply): Add prototype. (darwin_decode_exception_message): Reply to unknown inferiors. (darwin_decode_message): Handle message by id. Ignore message to unknown inferior. (darwin_wait): Discard unknown messages, add debug trace.
Diffstat (limited to 'gdb/darwin-nat.c')
-rw-r--r--gdb/darwin-nat.c144
1 files changed, 90 insertions, 54 deletions
diff --git a/gdb/darwin-nat.c b/gdb/darwin-nat.c
index 3ea9696..7d2508e 100644
--- a/gdb/darwin-nat.c
+++ b/gdb/darwin-nat.c
@@ -113,6 +113,9 @@ static char *darwin_pid_to_str (struct target_ops *ops, ptid_t tpid);
static int darwin_thread_alive (struct target_ops *ops, ptid_t tpid);
+static void darwin_encode_reply (mig_reply_error_t *reply,
+ mach_msg_header_t *hdr, integer_t code);
+
/* Target operations for Darwin. */
static struct target_ops *darwin_ops;
@@ -557,8 +560,8 @@ darwin_decode_exception_message (mach_msg_header_t *hdr,
kern_return_t kret;
int i;
- /* Check message identifier. 2401 == 0x961 is exc. */
- if (hdr->msgh_id != 2401)
+ /* Check message destination. */
+ if (hdr->msgh_local_port != darwin_ex_port)
return -1;
/* Check message header. */
@@ -588,25 +591,42 @@ darwin_decode_exception_message (mach_msg_header_t *hdr,
/* Ok, the hard work. */
data = (integer_t *)(ndr + 1);
- /* Find process by port. */
task_port = desc[1].name;
thread_port = desc[0].name;
+
+ /* We got new rights to the task and the thread. Get rid of them. */
+ kret = mach_port_deallocate (mach_task_self (), task_port);
+ MACH_CHECK_ERROR (kret);
+ kret = mach_port_deallocate (mach_task_self (), thread_port);
+ MACH_CHECK_ERROR (kret);
+
+ /* Find process by port. */
inf = darwin_find_inferior_by_task (task_port);
- if (inf == NULL)
- return -1;
*pinf = inf;
+ if (inf == NULL)
+ {
+ /* Not a known inferior. This could happen if the child fork, as
+ the created process will inherit its exception port.
+ FIXME: should the exception port be restored ? */
+ kern_return_t kret;
+ mig_reply_error_t reply;
+
+ darwin_encode_reply (&reply, hdr, KERN_SUCCESS);
+
+ kret = mach_msg (&reply.Head, MACH_SEND_MSG | MACH_SEND_INTERRUPT,
+ reply.Head.msgh_size, 0,
+ MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE,
+ MACH_PORT_NULL);
+ MACH_CHECK_ERROR (kret);
+
+ return 0;
+ }
/* Find thread by port. */
/* Check for new threads. Do it early so that the port in the exception
message can be deallocated. */
darwin_check_new_threads (inf);
- /* We got new rights to the task and the thread. Get rid of them. */
- kret = mach_port_deallocate (mach_task_self (), task_port);
- MACH_CHECK_ERROR (kret);
- kret = mach_port_deallocate (mach_task_self (), thread_port);
- MACH_CHECK_ERROR (kret);
-
thread = darwin_find_thread (inf, thread_port);
if (thread == NULL)
return -1;
@@ -863,8 +883,8 @@ darwin_decode_message (mach_msg_header_t *hdr,
darwin_thread_t *thread;
struct inferior *inf;
- /* Exception message. */
- if (hdr->msgh_local_port == darwin_ex_port)
+ /* Exception message. 2401 == 0x961 is exc. */
+ if (hdr->msgh_id == 2401)
{
int res;
@@ -877,7 +897,12 @@ darwin_decode_message (mach_msg_header_t *hdr,
printf_unfiltered
(_("darwin_wait: ill-formatted message (id=0x%x)\n"), hdr->msgh_id);
/* FIXME: send a failure reply? */
- status->kind = TARGET_WAITKIND_SPURIOUS;
+ status->kind = TARGET_WAITKIND_IGNORE;
+ return minus_one_ptid;
+ }
+ if (inf == NULL)
+ {
+ status->kind = TARGET_WAITKIND_IGNORE;
return minus_one_ptid;
}
*pinf = inf;
@@ -940,56 +965,60 @@ darwin_decode_message (mach_msg_header_t *hdr,
return ptid_build (inf->pid, 0, thread->gdb_port);
}
-
- *pinf = NULL;
- *pthread = NULL;
-
- inf = darwin_find_inferior_by_notify (hdr->msgh_local_port);
- if (inf != NULL)
+ else if (hdr->msgh_id == 0x48)
{
- if (!inf->private->no_ptrace)
- {
- pid_t res;
- int wstatus;
+ /* MACH_NOTIFY_DEAD_NAME: notification for exit. */
+ *pinf = NULL;
+ *pthread = NULL;
- res = wait4 (inf->pid, &wstatus, 0, NULL);
- if (res < 0 || res != inf->pid)
- {
- printf_unfiltered (_("wait4: res=%d: %s\n"),
- res, safe_strerror (errno));
- status->kind = TARGET_WAITKIND_SPURIOUS;
- return minus_one_ptid;
- }
- if (WIFEXITED (wstatus))
+ inf = darwin_find_inferior_by_notify (hdr->msgh_local_port);
+ if (inf != NULL)
+ {
+ if (!inf->private->no_ptrace)
{
- status->kind = TARGET_WAITKIND_EXITED;
- status->value.integer = WEXITSTATUS (wstatus);
+ pid_t res;
+ int wstatus;
+
+ res = wait4 (inf->pid, &wstatus, 0, NULL);
+ if (res < 0 || res != inf->pid)
+ {
+ printf_unfiltered (_("wait4: res=%d: %s\n"),
+ res, safe_strerror (errno));
+ status->kind = TARGET_WAITKIND_IGNORE;
+ return minus_one_ptid;
+ }
+ if (WIFEXITED (wstatus))
+ {
+ status->kind = TARGET_WAITKIND_EXITED;
+ status->value.integer = WEXITSTATUS (wstatus);
+ }
+ else
+ {
+ status->kind = TARGET_WAITKIND_SIGNALLED;
+ status->value.sig = WTERMSIG (wstatus);
+ }
+
+ inferior_debug (4, _("darwin_wait: pid=%d exit, status=0x%x\n"),
+ res, wstatus);
+
+ /* Looks necessary on Leopard and harmless... */
+ wait4 (inf->pid, &wstatus, 0, NULL);
+
+ return ptid_build (inf->pid, 0, 0);
}
else
{
- status->kind = TARGET_WAITKIND_SIGNALLED;
- status->value.sig = WTERMSIG (wstatus);
+ inferior_debug (4, _("darwin_wait: pid=%d\n"), inf->pid);
+ status->kind = TARGET_WAITKIND_EXITED;
+ status->value.integer = 0; /* Don't know. */
+ return ptid_build (inf->pid, 0, 0);
}
-
- inferior_debug (4, _("darwin_wait: pid=%d exit, status=0x%x\n"),
- res, wstatus);
-
- /* Looks necessary on Leopard and harmless... */
- wait4 (inf->pid, &wstatus, 0, NULL);
-
- return ptid_build (inf->pid, 0, 0);
- }
- else
- {
- inferior_debug (4, _("darwin_wait: pid=%d\n"), inf->pid);
- status->kind = TARGET_WAITKIND_EXITED;
- status->value.integer = 0; /* Don't know. */
- return ptid_build (inf->pid, 0, 0);
}
}
- printf_unfiltered (_("Bad local-port: 0x%x\n"), hdr->msgh_local_port);
- status->kind = TARGET_WAITKIND_SPURIOUS;
+ /* Unknown message. */
+ warning (_("darwin: got unknown message, id: 0x%x\n"), hdr->msgh_id);
+ status->kind = TARGET_WAITKIND_IGNORE;
return minus_one_ptid;
}
@@ -1082,7 +1111,10 @@ darwin_wait (ptid_t ptid, struct target_waitstatus *status)
darwin_dump_message (hdr, darwin_debug_flag > 11);
res = darwin_decode_message (hdr, &thread, &inf, status);
+ if (ptid_equal (res, minus_one_ptid))
+ continue;
+ /* Early return in case an inferior has exited. */
if (inf == NULL)
return res;
}
@@ -1110,6 +1142,10 @@ darwin_wait (ptid_t ptid, struct target_waitstatus *status)
break;
}
+ /* Debug: display message. */
+ if (darwin_debug_flag > 10)
+ darwin_dump_message (hdr, darwin_debug_flag > 11);
+
ptid2 = darwin_decode_message (hdr, &thread, &inf, &status2);
if (inf != NULL && thread != NULL