tests/test-posix_spawn-inherit0.c

   1 /* Test of posix_spawn() function with an inherited file descriptor 0.
   2    Copyright (C) 2008-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2020.  */
  18
  19 /* Test whether passing a file descriptor open for reading, including the
  20    current file position, works.  */
  21
  22 #include <config.h>
  23
  24 #include <spawn.h>
  25
  26 #include <errno.h>
  27 #include <signal.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <unistd.h>
  31 #include <sys/types.h>
  32 #include <sys/wait.h>
  33
  34 #define CHILD_PROGRAM_FILENAME "test-posix_spawn-inherit0" EXEEXT
  35 #define DATA_FILENAME "test-posix_spawn-inh0-data.tmp"
  36
  37 static int
  38 parent_main (void)
  39 {
  40   FILE *fp;
  41   char *argv[3] = { CHILD_PROGRAM_FILENAME, "-child", NULL };
  42   int err;
  43   pid_t child;
  44   int status;
  45   int exitstatus;
  46
  47   /* Create a data file with specific contents.  */
  48   fp = fopen (DATA_FILENAME, "wb");
  49   if (fp == NULL)
  50     {
  51       perror ("cannot create data file");
  52       return 1;
  53     }
  54   fwrite ("Halle Potta", 1, 11, fp);
  55   if (fflush (fp) || fclose (fp))
  56     {
  57       perror ("cannot prepare data file");
  58       return 1;
  59     }
  60
  61   /* Open the data file for reading.  */
  62   fp = freopen (DATA_FILENAME, "rb", stdin);
  63   if (fp == NULL)
  64     {
  65       perror ("cannot open data file");
  66       return 1;
  67     }
  68   if (fflush (fp) || fseek (fp, 6, SEEK_SET)) /* needs gnulib module 'fflush' */
  69     {
  70       perror ("cannot seek in data file");
  71       return 1;
  72     }
  73
  74   /* Test whether the child reads from fd 0 at the current file position.  */
  75   if ((err = posix_spawn (&child, CHILD_PROGRAM_FILENAME, NULL, NULL, argv, environ)) != 0)
  76     {
  77       errno = err;
  78       perror ("subprocess failed");
  79       return 1;
  80     }
  81   status = 0;
  82   while (waitpid (child, &status, 0) != child)
  83     ;
  84   if (!WIFEXITED (status))
  85     {
  86       fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
  87       return 1;
  88     }
  89   exitstatus = WEXITSTATUS (status);
  90   if (exitstatus != 0)
  91     {
  92       fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
  93       return 1;
  94     }
  95
  96   if (fclose (fp))
  97     {
  98       perror ("cannot close data file");
  99       return 1;
 100     }
 101
 102   /* Clean up data file.  */
 103   unlink (DATA_FILENAME);
 104
 105   return 0;
 106 }
 107
 108 static int
 109 child_main (void)
 110 {
 111   /* Read from STDIN_FILENO.  */
 112   char buf[1024];
 113   int nread = fread (buf, 1, sizeof (buf), stdin);
 114   if (!(nread == 5 && memcmp (buf, "Potta", 5) == 0))
 115     {
 116       fprintf (stderr, "child: read %d bytes, expected %d bytes\n", nread, 5);
 117       return 1;
 118     }
 119
 120   return 0;
 121 }
 122
 123 static void
 124 cleanup_then_die (int sig)
 125 {
 126   /* Clean up data file.  */
 127   unlink (DATA_FILENAME);
 128
 129   /* Re-raise the signal and die from it.  */
 130   signal (sig, SIG_DFL);
 131   raise (sig);
 132 }
 133
 134 int
 135 main (int argc, char *argv[])
 136 {
 137   int exitstatus;
 138
 139   if (!(argc > 1 && strcmp (argv[1], "-child") == 0))
 140     {
 141       /* This is the parent process.  */
 142       signal (SIGINT, cleanup_then_die);
 143       signal (SIGTERM, cleanup_then_die);
 144       #ifdef SIGHUP
 145       signal (SIGHUP, cleanup_then_die);
 146       #endif
 147
 148       exitstatus = parent_main ();
 149     }
 150   else
 151     {
 152       /* This is the child process.  */
 153       exitstatus = child_main ();
 154     }
 155   return exitstatus;
 156 }