lib/util/become_daemon.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 2001-2002
   6    Copyright (C) Simo Sorce 2001
   7    Copyright (C) Jim McDonough (jmcd@us.ibm.com)  2003.
   8    Copyright (C) James J Myers 2003
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "system/filesys.h"
  26 #include "system/locale.h"
  27 #if HAVE_SYSTEMD
  28 #include <systemd/sd-daemon.h>
  29 #endif
  30
  31 /*******************************************************************
  32  Close the low 3 fd's and open dev/null in their place.
  33 ********************************************************************/
  34
  35 _PUBLIC_ void close_low_fds(bool stdin_too, bool stdout_too, bool stderr_too)
  36 {
  37 #ifndef VALGRIND
  38         int fd;
  39         int i;
  40
  41         if (stdin_too)
  42                 close(0);
  43         if (stdout_too)
  44                 close(1);
  45
  46         if (stderr_too)
  47                 close(2);
  48
  49         /* try and use up these file descriptors, so silly
  50                 library routines writing to stdout etc won't cause havoc */
  51         for (i=0;i<3;i++) {
  52                 if (i == 0 && !stdin_too)
  53                         continue;
  54                 if (i == 1 && !stdout_too)
  55                         continue;
  56                 if (i == 2 && !stderr_too)
  57                         continue;
  58
  59                 fd = open("/dev/null",O_RDWR,0);
  60                 if (fd < 0)
  61                         fd = open("/dev/null",O_WRONLY,0);
  62                 if (fd < 0) {
  63                         DEBUG(0,("Can't open /dev/null\n"));
  64                         return;
  65                 }
  66                 if (fd != i) {
  67                         DEBUG(0,("Didn't get file descriptor %d\n",i));
  68                         close(fd);
  69                         return;
  70                 }
  71         }
  72 #endif
  73 }
  74
  75 /****************************************************************************
  76  Become a daemon, discarding the controlling terminal.
  77 ****************************************************************************/
  78
  79 _PUBLIC_ void become_daemon(bool do_fork, bool no_process_group, bool log_stdout)
  80 {
  81         pid_t newpid;
  82         if (do_fork) {
  83                 newpid = fork();
  84                 if (newpid) {
  85 #if HAVE_SYSTEMD
  86                         sd_notifyf(0, "READY=0\nSTATUS=Starting process...\nMAINPID=%lu", (unsigned long) newpid);
  87 #endif /* HAVE_SYSTEMD */
  88                         _exit(0);
  89                 }
  90         }
  91
  92         /* detach from the terminal */
  93 #ifdef HAVE_SETSID
  94         if (!no_process_group) setsid();
  95 #elif defined(TIOCNOTTY)
  96         if (!no_process_group) {
  97                 int i = open("/dev/tty", O_RDWR, 0);
  98                 if (i != -1) {
  99                         ioctl(i, (int) TIOCNOTTY, (char *)0);
 100                         close(i);
 101                 }
 102         }
 103 #endif /* HAVE_SETSID */
 104
 105         /* Close fd's 0,1,2 as appropriate. Needed if started by rsh. */
 106         /* stdin must be open if we do not fork, for monitoring for
 107          * close.  stdout must be open if we are logging there, and we
 108          * never close stderr (but debug might dup it onto a log file) */
 109         close_low_fds(do_fork, !log_stdout, false);
 110 }
 111
 112 _PUBLIC_ void exit_daemon(const char *msg, int error)
 113 {
 114 #ifdef HAVE_SYSTEMD
 115         if (msg == NULL) {
 116                 msg = strerror(error);
 117         }
 118
 119         sd_notifyf(0, "STATUS=daemon failed to start: %s\n"
 120                                   "ERRNO=%i",
 121                                   msg,
 122                                   error);
 123 #endif
 124         DEBUG(0, ("STATUS=daemon failed to start: %s, error code %d\n", msg, error));
 125         exit(1);
 126 }
 127
 128 _PUBLIC_ void daemon_ready(const char *daemon)
 129 {
 130         if (daemon == NULL) {
 131                 daemon = "Samba";
 132         }
 133 #ifdef HAVE_SYSTEMD
 134         sd_notifyf(0, "READY=1\nSTATUS=%s: ready to serve connections...", daemon);
 135 #endif
 136         DEBUG(0, ("STATUS=daemon '%s' finished starting up and ready to serve connections", daemon));
 137 }