posix/tst-spawn3.c

   1 /* Check posix_spawn add file actions.
   2    Copyright (C) 2016-2024 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 <spawn.h>
  21 #include <error.h>
  22 #include <errno.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <sys/wait.h>
  27 #include <sys/resource.h>
  28 #include <fcntl.h>
  29 #include <paths.h>
  30 #include <intprops.h>
  31
  32 #include <support/check.h>
  33 #include <support/temp_file.h>
  34 #include <support/xunistd.h>
  35 #include <tst-spawn.h>
  36
  37 static int
  38 do_test (void)
  39 {
  40   /* The test checks if posix_spawn open file action close the file descriptor
  41      before opening a new one in case the input file descriptor is already
  42      opened.  It does by exhausting all file descriptors on the process before
  43      issue posix_spawn.  It then issues a posix_spawn for '/bin/sh echo $$'
  44      and add two rules:
  45
  46      1. Redirect stdout to a temporary filepath
  47      2. Redirect stderr to stdout
  48
  49      If the implementation does not close the file 1. will fail with
  50      EMFILE.  */
  51
  52   struct rlimit rl;
  53   int max_fd = 24;
  54
  55   /* Set maximum number of file descriptor to a low value to avoid open
  56      too many files in environments where RLIMIT_NOFILE is large and to
  57      limit the array size to track the opened file descriptors.  */
  58
  59   if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
  60     FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
  61
  62   max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
  63   rl.rlim_cur = max_fd;
  64
  65   if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
  66     FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
  67
  68   /* Exhauste the file descriptor limit with temporary files.  */
  69   int files[max_fd];
  70   int nfiles = 0;
  71   for (; nfiles < max_fd; nfiles++)
  72     {
  73       int fd = create_temp_file ("tst-spawn3.", NULL);
  74       if (fd == -1)
  75         {
  76           if (errno != EMFILE)
  77             FAIL_EXIT1 ("create_temp_file: %m");
  78           break;
  79         }
  80       files[nfiles] = fd;
  81     }
  82   TEST_VERIFY_EXIT (nfiles != 0);
  83
  84   posix_spawn_file_actions_t a;
  85   TEST_COMPARE (posix_spawn_file_actions_init (&a), 0);
  86
  87   /* Executes a /bin/sh echo $$ 2>&1 > ${objpfx}tst-spawn3.pid .  */
  88   const char pidfile[] = OBJPFX "tst-spawn3.pid";
  89   TEST_COMPARE (posix_spawn_file_actions_addopen (&a, STDOUT_FILENO, pidfile,
  90                                                   O_WRONLY| O_CREAT | O_TRUNC,
  91                                                   0644),
  92                 0);
  93
  94   TEST_COMPARE (posix_spawn_file_actions_adddup2 (&a, STDOUT_FILENO,
  95                                                   STDERR_FILENO),
  96                 0);
  97
  98   /* Since execve (called by posix_spawn) might require to open files to
  99      actually execute the shell script, setup to close the temporary file
 100      descriptors.  */
 101   int maxnfiles =
 102 #ifdef TST_SPAWN_PIDFD
 103     /* The sparing file descriptor will be returned as the pid descriptor,
 104        otherwise clone fail with EMFILE.  */
 105     nfiles - 1;
 106 #else
 107     nfiles;
 108 #endif
 109
 110   for (int i=0; i<maxnfiles; i++)
 111     TEST_COMPARE (posix_spawn_file_actions_addclose (&a, files[i]), 0);
 112
 113   char *spawn_argv[] = { (char *) _PATH_BSHELL, (char *) "-c",
 114                          (char *) "echo $$", NULL };
 115   PID_T_TYPE pid;
 116
 117   {
 118     int r = POSIX_SPAWN (&pid, _PATH_BSHELL, &a, NULL, spawn_argv, NULL);
 119     if (r == ENOSYS)
 120       FAIL_UNSUPPORTED ("kernel does not support CLONE_PIDFD clone flag");
 121 #ifdef TST_SPAWN_PIDFD
 122     TEST_COMPARE (r, EMFILE);
 123
 124     /* Free up one file descriptor, so posix_spawn_pidfd_ex can return it.  */
 125     xclose (files[nfiles-1]);
 126     nfiles--;
 127     r = POSIX_SPAWN (&pid, _PATH_BSHELL, &a, NULL, spawn_argv, NULL);
 128 #endif
 129     TEST_COMPARE (r, 0);
 130   }
 131
 132   siginfo_t sinfo;
 133   TEST_COMPARE (WAITID (P_PID, pid, &sinfo, WEXITED), 0);
 134   TEST_COMPARE (sinfo.si_code, CLD_EXITED);
 135   TEST_COMPARE (sinfo.si_status, 0);
 136
 137   /* Close the temporary files descriptor so it can check posix_spawn
 138      output.  */
 139   for (int i=0; i<nfiles; i++)
 140     xclose (files[i]);
 141
 142   int pidfd = xopen (pidfile, O_RDONLY, 0);
 143
 144   char buf[INT_BUFSIZE_BOUND (pid_t)];
 145   ssize_t n = read (pidfd, buf, sizeof (buf));
 146   TEST_VERIFY (n < sizeof buf && n >= 0);
 147
 148   xunlink (pidfile);
 149
 150   /* We only expect to read the PID.  */
 151   char *endp;
 152   long int rpid = strtol (buf, &endp, 10);
 153   TEST_VERIFY (*endp == '\n' && endp != buf);
 154
 155   TEST_COMPARE (rpid, sinfo.si_pid);
 156
 157   return 0;
 158 }
 159
 160 #include <support/test-driver.c>