1  /* Test of posix_spawn() function with an inherited file descriptor 1.
       2     Copyright (C) 2008-2023 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 writing, 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-inherit1" EXEEXT
      35  #define DATA_FILENAME "test-posix_spawn-inh1-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 = freopen (DATA_FILENAME, "wb", stdout);
      49    if (fp == NULL)
      50      {
      51        perror ("cannot create data file");
      52        return 1;
      53      }
      54    fwrite ("Halle X", 1, 7, fp);
      55    if (fflush (fp) || fseek (fp, 6, SEEK_SET))
      56      {
      57        perror ("cannot prepare data file");
      58        return 1;
      59      }
      60  
      61    /* Test whether the child writes to fd 1 at the current file position.  */
      62    if ((err = posix_spawn (&child, CHILD_PROGRAM_FILENAME, NULL, NULL, argv, environ)) != 0)
      63      {
      64        errno = err;
      65        perror ("subprocess failed");
      66        return 1;
      67      }
      68    status = 0;
      69    while (waitpid (child, &status, 0) != child)
      70      ;
      71    if (!WIFEXITED (status))
      72      {
      73        fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
      74        return 1;
      75      }
      76    exitstatus = WEXITSTATUS (status);
      77    if (exitstatus != 0)
      78      {
      79        fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
      80        return 1;
      81      }
      82  
      83    if (fclose (fp))
      84      {
      85        perror ("cannot close data file");
      86        return 1;
      87      }
      88  
      89    /* Check the contents of the data file.  */
      90    fp = fopen (DATA_FILENAME, "rb");
      91    if (fp == NULL)
      92      {
      93        perror ("cannot open data file");
      94        return 1;
      95      }
      96    char buf[1024];
      97    int nread = fread (buf, 1, sizeof (buf), fp);
      98    if (!(nread == 11 && memcmp (buf, "Halle Potta", 11) == 0))
      99      {
     100        fprintf (stderr, "data file wrong: has %d bytes, expected %d bytes\n", nread, 11);
     101        return 1;
     102      }
     103    if (fclose (fp))
     104      {
     105        perror ("cannot close data file");
     106        return 1;
     107      }
     108  
     109    /* Clean up data file.  */
     110    unlink (DATA_FILENAME);
     111  
     112    return 0;
     113  }
     114  
     115  static int
     116  child_main (void)
     117  {
     118    /* Write to STDOUT_FILENO.  */
     119    fwrite ("Potta", 1, 5, stdout);
     120    /* No 'fflush (stdout);' is needed.  It is implicit when the child process
     121       exits.  */
     122  
     123    return 0;
     124  }
     125  
     126  static void
     127  cleanup_then_die (int sig)
     128  {
     129    /* Clean up data file.  */
     130    unlink (DATA_FILENAME);
     131  
     132    /* Re-raise the signal and die from it.  */
     133    signal (sig, SIG_DFL);
     134    raise (sig);
     135  }
     136  
     137  int
     138  main (int argc, char *argv[])
     139  {
     140    int exitstatus;
     141  
     142    if (!(argc > 1 && strcmp (argv[1], "-child") == 0))
     143      {
     144        /* This is the parent process.  */
     145        signal (SIGINT, cleanup_then_die);
     146        signal (SIGTERM, cleanup_then_die);
     147        #ifdef SIGHUP
     148        signal (SIGHUP, cleanup_then_die);
     149        #endif
     150  
     151        exitstatus = parent_main ();
     152      }
     153    else
     154      {
     155        /* This is the child process.  */
     156        exitstatus = child_main ();
     157      }
     158    return exitstatus;
     159  }