1  /* Test of posix_spawn() function with an inherited file descriptor 0.
       2     Copyright (C) 2008-2021 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"
      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  }