Fix a recently-introduced delete-process race condition.

* callproc.c, process.h (record_kill_process):
New function, containing part of the old call_process_kill.
(call_process_kill): Use it.
This does not change call_process_kill's behavior.
* process.c (Fdelete_process): Use record_kill_process to fix a
race condition that could cause Emacs to lose track of a child.

1 files changed, 14 insertions, 22 deletions

diff --git a/src/process.c b/src/process.c
index 27009882c99..007a07942e6 100644
--- a/src/process.c
+++ b/src/process.c
@@ -813,30 +813,22 @@ nil, indicating the current buffer's process.  */)
       status_notify (p);
       redisplay_preserve_echo_area (13);
     }
-  else if (p->infd >= 0)
+  else
     {
-#ifdef SIGCHLD
-      Lisp_Object symbol;
-      pid_t pid = p->pid;
-
-      /* No problem storing the pid here, as it is still in Vprocess_alist.  */
-      record_deleted_pid (pid);
-      /* If the process has already signaled, remove it from the list.  */
-      if (p->raw_status_new)
-        update_status (p);
-      symbol = p->status;
-      if (CONSP (p->status))
-        symbol = XCAR (p->status);
-      if (EQ (symbol, Qsignal) || EQ (symbol, Qexit))
-        deleted_pid_list
-          = Fdelete (make_fixnum_or_float (pid), deleted_pid_list);
-      else
-#endif
+      if (p->alive)
+        record_kill_process (p);
+
+      if (p->infd >= 0)
         {
-          Fkill_process (process, Qnil);
-          /* Do this now, since remove_process will make the
-             SIGCHLD handler do nothing.  */
-          pset_status (p, Fcons (Qsignal, Fcons (make_number (SIGKILL), Qnil)));
+          /* Update P's status, since record_kill_process will make the
+             SIGCHLD handler update deleted_pid_list, not *P.  */
+          Lisp_Object symbol;
+          if (p->raw_status_new)
+            update_status (p);
+          symbol = CONSP (p->status) ? XCAR (p->status) : p->status;
+          if (! (EQ (symbol, Qsignal) || EQ (symbol, Qexit)))
+            pset_status (p, list2 (Qsignal, make_number (SIGKILL)));
+
           p->tick = ++process_tick;
           status_notify (p);
           redisplay_preserve_echo_area (13);