prefork: new plan - make fa-monitor like the normal monitor

[chiark-utils.git] / cprogs / prefork-interp.c

diff --git a/cprogs/prefork-interp.c b/cprogs/prefork-interp.c
index 916fdefcfad249bf932e3b68b6a60b38683f0c48..018a7919ddaa5f0a623e04cbc762f561e64afc91 100644 (file)
--- a/cprogs/prefork-interp.c
+++ b/cprogs/prefork-interp.c
@@ -16,16 +16,16 @@
  *                               makes new listening socket
  *                               makes first-instance socketpair
  *                            forks setup (script, sock fds indicated in env)
- *                            fd0, fd1, fd2: from-outer-caller
+ *                            fd0, fd1, fd2: from-outer
  *                            other fd: call(client-end)(fake)
  *                            reaps setup (and reports error)
  *                            (implicitly releases lock)
  *
  *     setup (pre-exec)       fd0: null,
- *                            fd[12: fd2-from-outer-caller
+ *                            fd[12]: fd2-from-outer
  *                            env fds: listener, call(server-end)(fake)
- *                            env fds: orig-fd[01]
  *                            close fd: lockfile
+ *                            possibly clean env, argv
  *
  *     setup (script)         runs initialisation parts of the script
  *                            at prefork establishment point:
@@ -34,37 +34,32 @@
  *                [2]         exits
  *
  #        server (pm) [1]     [fd0: null],
- *                            [fd[12: fd2-from-outer-caller]
- *                            right away, forks one fa-monitor
+ *                            [fd[12]: fd2-from-outer]
+ *                            right away, forks init monitor
  *                    [2]     closes outer caller fds and call(fake)
  *        [server (pm)]       fd[012]: null
  *                            other fds: listener, syslog
  *                            runs in loop accepting and forking,
- *                            reaping and limiting children (incl fa-monitor)
+ *                            reaping and limiting children (incl init monitor)
  *                            reports failures of monitors to syslog
  *                            
- *         f-a monitor        forks executor
- *                            closes fd: listener
- *                            [fd[12: fd2-from-outer-caller]
- *                            [other fds: call(server-end)(fake), syslog]
- *                            runs as monitor, below
- *
- *
  *  [client (C wrapper)]      if client connect succeeds:
  *                            now fd: call(client-end)
  *                               sends message with: cmdline, env
  *                               sends fds
  *
- *        [server (script)]   accepts, forks monitor
+ *        [server (script)]   accepts, forks subseq monitor
  *
- *          monitor [1]       [fd[012]: null]
- *                            other fds: syslog, call(server-end)
+ *          monitor [1]       [fd0: null]
+ *           (init            [fd[12]: init: fd2-from-outer; subseq: null]
+ *             or             errors: init: fd2; subseq: syslog
+ *            subseq)         other fds: syslog, call(server-end)
  *                            sends ack byte
  *                            receives args, env, fds
  *                            forks executor
  *
  *            executor        sorts out fds:
- *                            fd0, fd1, fd2: from-outer-caller
+ *                            fd0, fd1, fd2: from-outer
  *                            close fds: call(server-end)
  *                            retained fds: syslog
  *
@@ -73,11 +68,12 @@
  *                            exits normally
  *
  *          [monitor]         [fd[012]: null]
- *                            [other fds: call(server-end), syslog]
+ *                            [fd[12]: init: fd2-from-outer; subseq: null]
+ *                            [errors: init: fd2; subseq: syslog]
  *                            reaps executor
  *                            reports status via socket
  *
- *    [client (C wrapper)]    [fd0, fd1, fd2: from-outer-caller]
+ *    [client (C wrapper)]    [fd0, fd1, fd2: from-outer]
  *                            [other fd: call(client-end)]
  *                            receives status, exits appropriately
  *                            (if was bad signal, reports to stderr, exits 127)
@@ -341,7 +337,8 @@ static FILE *connect_or_spawn(void) {
   // We must start a fresh one, and we hold the lock
 
   r = unlink(socket_path);
-  if (r<0) diee("failed to remove stale socket %s", socket_path);
+  if (r<0 && errno!=ENOENT)
+    diee("failed to remove stale socket %s", socket_path);
 
   int fake_pair[2];
   r = socketpair(AF_UNIX, SOCK_STREAM, 0, fake_pair);