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darwin-nat: avoid crash while debugging gdb.

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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.
This commit is contained in:
Tristan Gingold 2014-03-21 16:56:39 +01:00
parent 98d1b8dcd8
commit a41f2563d0
2 changed files with 99 additions and 55 deletions
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8
gdb/ChangeLog
View File

@ -1,3 +1,11 @@
2014-04-01 Tristan Gingold <gingold@adacore.com>
* 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.
2014-03-31 Doug Evans <dje@google.com>
* dwarf2read.c (read_cutu_die_from_dwo): Delete unused local

146
gdb/darwin-nat.c
View File

@ -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. */
@ -588,18 +591,8 @@ 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;
inf = darwin_find_inferior_by_task (task_port);
if (inf == NULL)
return -1;
*pinf = inf;
/* 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);
@ -607,6 +600,33 @@ darwin_decode_exception_message (mach_msg_header_t *hdr,
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);
*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);
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)
inf = darwin_find_inferior_by_notify (hdr->msgh_local_port);
if (inf != NULL)
{
if (!inf->private->no_ptrace)
{
printf_unfiltered (_("wait4: res=%d: %s\n"),
res, safe_strerror (errno));
status->kind = TARGET_WAITKIND_SPURIOUS;
return minus_one_ptid;
}
if (WIFEXITED (wstatus))
{
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