gdb/darwin: skip over WIFSTOPPED wait4 status

On modern Darwin's, there appears to be a new circumstance in which a
MACH_NOTIFY_DEAD_NAME message can be received, and which was not
previously accounted for: to signal the WIFSTOPPED condition in the
debuggee. In that case the debuggee is not dead yet (and in fact,
counting it as dead would cause a zombie leak - A process in such a
state reparents to PID 1, but cannot be killed).

 - Read and ignore such messages (counting on the next exception message
   to let us know of the inferior's new state again)
 - Refactor logging so as to clearly distinguish between the
   MACH_NOTIFY_DEAD_NAME cases (WIFEXITED, WIFSTOPPED, signal, or
   something else), and warn in the last case

Co-authored-by: Louis-He <1726110778@qq.com>
Co-authored-by: Philippe Blain <levraiphilippeblain@gmail.com>
Change-Id: Ie86904a894e9bd154e6b674b1bfbfbaee7fde3e1
This commit is contained in:
Dominique Quatravaux
2022-02-24 09:23:21 -05:00
committed by Simon Marchi
parent 0b313e95a7
commit 7ff917016a

View File

@ -1063,7 +1063,7 @@ darwin_nat_target::decode_message (mach_msg_header_t *hdr,
}
else if (hdr->msgh_id == 0x48)
{
/* MACH_NOTIFY_DEAD_NAME: notification for exit. */
/* MACH_NOTIFY_DEAD_NAME: notification for exit *or* WIFSTOPPED. */
int res;
res = darwin_decode_notify_message (hdr, &inf);
@ -1103,15 +1103,34 @@ darwin_nat_target::decode_message (mach_msg_header_t *hdr,
return minus_one_ptid;
}
if (WIFEXITED (wstatus))
{
status->set_exited (WEXITSTATUS (wstatus));
else
inferior_debug (4, _("darwin_wait: pid=%d exit, status=0x%x\n"),
res_pid, wstatus);
}
else if (WIFSTOPPED (wstatus))
{
/* Ignore stopped state, it will be handled by the next
exception. */
status->set_ignore ();
inferior_debug (4, _("darwin_wait: pid %d received WIFSTOPPED\n"),
res_pid);
return minus_one_ptid;
}
else if (WIFSIGNALED (wstatus))
{
status->set_signalled
(gdb_signal_from_host (WTERMSIG (wstatus)));
inferior_debug (4, _("darwin_wait: pid=%d received signal %d\n"),
res_pid, status->sig());
}
else
{
status->set_ignore ();
warning (_("Unexpected wait status after MACH_NOTIFY_DEAD_NAME "
"notification: 0x%x"), wstatus);
return minus_one_ptid;
}
inferior_debug (4, _("darwin_wait: pid=%d exit, status=0x%x\n"),
res_pid, wstatus);
return ptid_t (inf->pid);
}