Re: bin/41302: cron dies at startup

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR bin/41302; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: bin/41302: cron dies at startup
Date: Sun, 3 May 2009 12:14:28 +0200

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 This is a patch similar to what FreeBSD did to fix this problem (only 
 difference is restoring the signal handler when fork() fails.
 
 OK to commit?
 
 Martin
 
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 Index: daemon.c
 ===================================================================
 RCS file: /cvsroot/src/lib/libc/gen/daemon.c,v
 retrieving revision 1.9
 diff -u -r1.9 daemon.c
 --- daemon.c   7 Aug 2003 16:42:46 -0000       1.9
 +++ daemon.c   3 May 2009 10:11:17 -0000
 @@ -39,9 +39,11 @@
  #endif /* LIBC_SCCS and not lint */
  
  #include "namespace.h"
 +#include <errno.h>
  #include <fcntl.h>
  #include <paths.h>
  #include <stdlib.h>
 +#include <signal.h>
  #include <unistd.h>
  
  #ifdef __weak_alias
 @@ -52,10 +54,25 @@
  daemon(nochdir, noclose)
        int nochdir, noclose;
  {
 +      struct sigaction osa, sa;
        int fd;
 +      pid_t newgrp;
 +      int oerrno;
 +      int osa_ok;
 +
 +      /* A SIGHUP may be thrown when the parent exits below. */
 +      sigemptyset(&sa.sa_mask);
 +      sa.sa_handler = SIG_IGN;
 +      sa.sa_flags = 0;
 +      osa_ok = sigaction(SIGHUP, &sa, &osa);
  
        switch (fork()) {
        case -1:
 +              if (osa_ok != -1) {
 +                      oerrno = errno;
 +                      sigaction(SIGHUP, &osa, NULL);
 +                      errno = oerrno;
 +              }
                return (-1);
        case 0:
                break;
 @@ -63,8 +80,14 @@
                _exit(0);
        }
  
 -      if (setsid() == -1)
 +      newgrp = setsid();
 +      oerrno = errno;
 +      if (osa_ok != -1)
 +              sigaction(SIGHUP, &osa, NULL);
 +      if (newgrp == -1) {
 +              errno = oerrno;
                return (-1);
 +      }
  
        if (!nochdir)
                (void)chdir("/");
 
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