support/support_subprocess.c

   1 /* Create subprocess.
   2    Copyright (C) 2019-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <signal.h>
  21 #include <time.h>
  22 #include <sys/wait.h>
  23 #include <stdbool.h>
  24 #include <support/xspawn.h>
  25 #include <support/check.h>
  26 #include <support/xunistd.h>
  27 #include <support/subprocess.h>
  28
  29 static struct support_subprocess
  30 support_subprocess_init (void)
  31 {
  32   struct support_subprocess result;
  33
  34   xpipe (result.stdout_pipe);
  35   TEST_VERIFY (result.stdout_pipe[0] > STDERR_FILENO);
  36   TEST_VERIFY (result.stdout_pipe[1] > STDERR_FILENO);
  37
  38   xpipe (result.stderr_pipe);
  39   TEST_VERIFY (result.stderr_pipe[0] > STDERR_FILENO);
  40   TEST_VERIFY (result.stderr_pipe[1] > STDERR_FILENO);
  41
  42   TEST_VERIFY (fflush (stdout) == 0);
  43   TEST_VERIFY (fflush (stderr) == 0);
  44
  45   return result;
  46 }
  47
  48 struct support_subprocess
  49 support_subprocess (void (*callback) (void *), void *closure)
  50 {
  51   struct support_subprocess result = support_subprocess_init ();
  52
  53   result.pid = xfork ();
  54   if (result.pid == 0)
  55     {
  56       xclose (result.stdout_pipe[0]);
  57       xclose (result.stderr_pipe[0]);
  58       xdup2 (result.stdout_pipe[1], STDOUT_FILENO);
  59       xdup2 (result.stderr_pipe[1], STDERR_FILENO);
  60       xclose (result.stdout_pipe[1]);
  61       xclose (result.stderr_pipe[1]);
  62       callback (closure);
  63       _exit (0);
  64     }
  65   xclose (result.stdout_pipe[1]);
  66   xclose (result.stderr_pipe[1]);
  67
  68   return result;
  69 }
  70
  71 struct support_subprocess
  72 support_subprogram (const char *file, char *const argv[])
  73 {
  74   struct support_subprocess result = support_subprocess_init ();
  75
  76   posix_spawn_file_actions_t fa;
  77   /* posix_spawn_file_actions_init does not fail.  */
  78   posix_spawn_file_actions_init (&fa);
  79
  80   xposix_spawn_file_actions_addclose (&fa, result.stdout_pipe[0]);
  81   xposix_spawn_file_actions_addclose (&fa, result.stderr_pipe[0]);
  82   xposix_spawn_file_actions_adddup2 (&fa, result.stdout_pipe[1], STDOUT_FILENO);
  83   xposix_spawn_file_actions_adddup2 (&fa, result.stderr_pipe[1], STDERR_FILENO);
  84   xposix_spawn_file_actions_addclose (&fa, result.stdout_pipe[1]);
  85   xposix_spawn_file_actions_addclose (&fa, result.stderr_pipe[1]);
  86
  87   result.pid = xposix_spawn (file, &fa, NULL, argv, environ);
  88
  89   xclose (result.stdout_pipe[1]);
  90   xclose (result.stderr_pipe[1]);
  91
  92   return result;
  93 }
  94
  95 int
  96 support_subprogram_wait (const char *file, char *const argv[])
  97 {
  98   posix_spawn_file_actions_t fa;
  99
 100   posix_spawn_file_actions_init (&fa);
 101   struct support_subprocess res = support_subprocess_init ();
 102
 103   res.pid = xposix_spawn (file, &fa, NULL, argv, environ);
 104
 105   return support_process_wait (&res);
 106 }
 107
 108 int
 109 support_process_wait (struct support_subprocess *proc)
 110 {
 111   xclose (proc->stdout_pipe[0]);
 112   xclose (proc->stderr_pipe[0]);
 113
 114   int status;
 115   xwaitpid (proc->pid, &status, 0);
 116   return status;
 117 }
 118
 119
 120 static bool
 121 support_process_kill (int pid, int signo, int *status)
 122 {
 123   /* Kill the whole process group.  */
 124   kill (-pid, signo);
 125   /* In case setpgid failed in the child, kill it individually too.  */
 126   kill (pid, signo);
 127
 128   /* Wait for it to terminate.  */
 129   pid_t killed;
 130   for (int i = 0; i < 5; ++i)
 131     {
 132       int status;
 133       killed = xwaitpid (pid, &status, WNOHANG|WUNTRACED);
 134       if (killed != 0)
 135         break;
 136
 137       /* Delay, give the system time to process the kill.  If the
 138          nanosleep() call return prematurely, all the better.  We
 139          won't restart it since this probably means the child process
 140          finally died.  */
 141       nanosleep (&((struct timespec) { 0, 100000000 }), NULL);
 142     }
 143   if (killed != 0 && killed != pid)
 144     return false;
 145
 146   return true;
 147 }
 148
 149 int
 150 support_process_terminate (struct support_subprocess *proc)
 151 {
 152   xclose (proc->stdout_pipe[0]);
 153   xclose (proc->stderr_pipe[0]);
 154
 155   int status;
 156   pid_t killed = xwaitpid (proc->pid, &status, WNOHANG|WUNTRACED);
 157   if (killed != 0 && killed == proc->pid)
 158     return status;
 159
 160   /* Subprocess is still running, terminate it.  */
 161   if (!support_process_kill (proc->pid, SIGTERM, &status) )
 162     support_process_kill (proc->pid, SIGKILL, &status);
 163
 164   return status;
 165 }