tests/test-posix_spawn-fchdir.c

   1 /* Test of posix_spawn() function with 'fchdir' action.
   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>, 2018.  */
  18
  19 #include <config.h>
  20
  21 #include <spawn.h>
  22
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <signal.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include <sys/types.h>
  31 #include <sys/wait.h>
  32
  33 #include "findprog.h"
  34 #include "qemu.h"
  35 #include "xvasprintf.h"
  36
  37 static bool is_qemu;
  38
  39 static int
  40 fd_safer (int fd)
  41 {
  42   if (0 <= fd && fd <= 2)
  43     {
  44       int f = fd_safer (dup (fd));
  45       int e = errno;
  46       close (fd);
  47       errno = e;
  48       fd = f;
  49     }
  50
  51   return fd;
  52 }
  53
  54 static void
  55 test (const char *pwd_prog)
  56 {
  57   char *argv[2] = { (char *) "pwd", NULL };
  58   /* The name of a directory that most likely is accessible.  */
  59   #if defined __ANDROID__
  60     #define KNOWNDIR "/proc"
  61   #else
  62     #define KNOWNDIR "/"
  63   #endif
  64   int knownfd;
  65   int ifd[2];
  66   sigset_t blocked_signals;
  67   sigset_t fatal_signal_set;
  68   posix_spawn_file_actions_t actions;
  69   bool actions_allocated;
  70   posix_spawnattr_t attrs;
  71   bool attrs_allocated;
  72   int err;
  73   pid_t child;
  74   int fd;
  75   FILE *fp;
  76   char line[80];
  77   int status;
  78   int exitstatus;
  79
  80   knownfd = open (KNOWNDIR, O_RDONLY);
  81   if (knownfd < 0)
  82     {
  83       perror ("cannot open directory");
  84       exit (1);
  85     }
  86   if (pipe (ifd) < 0 || (ifd[0] = fd_safer (ifd[0])) < 0)
  87     {
  88       perror ("cannot create pipe");
  89       exit (1);
  90     }
  91   sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
  92   sigemptyset (&fatal_signal_set);
  93   sigaddset (&fatal_signal_set, SIGINT);
  94   sigaddset (&fatal_signal_set, SIGTERM);
  95   #ifdef SIGHUP
  96   sigaddset (&fatal_signal_set, SIGHUP);
  97   #endif
  98   #ifdef SIGPIPE
  99   sigaddset (&fatal_signal_set, SIGPIPE);
 100   #endif
 101   sigprocmask (SIG_BLOCK, &fatal_signal_set, NULL);
 102   actions_allocated = false;
 103   attrs_allocated = false;
 104   if ((err = posix_spawn_file_actions_init (&actions)) != 0
 105       || (actions_allocated = true,
 106           (err = posix_spawn_file_actions_adddup2 (&actions, ifd[1], STDOUT_FILENO)) != 0
 107           || (err = posix_spawn_file_actions_addclose (&actions, ifd[1])) != 0
 108           || (err = posix_spawn_file_actions_addclose (&actions, ifd[0])) != 0
 109           || (err = posix_spawn_file_actions_addopen (&actions, STDIN_FILENO, "/dev/null", O_RDONLY, 0)) != 0
 110           || (err = posix_spawn_file_actions_addfchdir (&actions, knownfd)) != 0
 111           || (err = posix_spawnattr_init (&attrs)) != 0
 112           || (attrs_allocated = true,
 113               #if defined _WIN32 && !defined __CYGWIN__
 114               0
 115               #else
 116               (err = posix_spawnattr_setsigmask (&attrs, &blocked_signals)) != 0
 117               || (err = posix_spawnattr_setflags (&attrs, POSIX_SPAWN_SETSIGMASK)) != 0
 118               #endif
 119              )
 120           || (err = posix_spawnp (&child, pwd_prog, &actions, &attrs, argv, environ)) != 0))
 121     {
 122       if (actions_allocated)
 123         posix_spawn_file_actions_destroy (&actions);
 124       if (attrs_allocated)
 125         posix_spawnattr_destroy (&attrs);
 126       sigprocmask (SIG_UNBLOCK, &fatal_signal_set, NULL);
 127       errno = err;
 128       perror ("subprocess failed");
 129       exit (1);
 130     }
 131   posix_spawn_file_actions_destroy (&actions);
 132   posix_spawnattr_destroy (&attrs);
 133   sigprocmask (SIG_UNBLOCK, &fatal_signal_set, NULL);
 134   close (ifd[1]);
 135   fd = ifd[0];
 136   fp = fdopen (fd, "r");
 137   if (fp == NULL)
 138     {
 139       fprintf (stderr, "fdopen() failed\n");
 140       exit (1);
 141     }
 142   if (fread (line, 1, 80, fp) < 2)
 143     {
 144       fprintf (stderr, "could not read expected output\n");
 145       exit (1);
 146     }
 147   /* For a process running under QEMU user-mode, knownfd points to the directory
 148      that is the value of the QEMU_LD_PREFIX environment variable or of the -L
 149      command-line option, and the line produced by 'pwd' is that directory, not
 150      "/".  */
 151   if (!is_qemu)
 152     {
 153       if (memcmp (line, KNOWNDIR "\n", strlen (KNOWNDIR) + 1) != 0)
 154         {
 155           fprintf (stderr, "read output is not the expected output\n");
 156           exit (1);
 157         }
 158     }
 159   fclose (fp);
 160   status = 0;
 161   while (waitpid (child, &status, 0) != child)
 162     ;
 163   if (!WIFEXITED (status))
 164     {
 165       fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
 166       exit (1);
 167     }
 168   exitstatus = WEXITSTATUS (status);
 169   if (exitstatus != 0)
 170     {
 171       fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
 172       exit (1);
 173     }
 174 }
 175
 176 int
 177 main ()
 178 {
 179   is_qemu = is_running_under_qemu_user ();
 180
 181   test ("pwd");
 182
 183   /* Verify that if a program is given as a relative file name with at least one
 184      slash, it is interpreted w.r.t. the current directory after fchdir has been
 185      executed.  */
 186   if (!is_qemu)
 187     {
 188       const char *abs_pwd_prog = find_in_path ("pwd");
 189
 190       if (abs_pwd_prog != NULL
 191           && abs_pwd_prog[0] == '/'
 192           && abs_pwd_prog[1] != '0' && abs_pwd_prog[1] != '/')
 193         {
 194           /* Determine the location of the 'pwd' program, relative to
 195              KNOWNDIR.  */
 196           const char *relative_pwd_prog;
 197           #if defined __ANDROID__
 198           relative_pwd_prog = xasprintf ("..%s", abs_pwd_prog);
 199           #else
 200           relative_pwd_prog = &abs_pwd_prog[1];
 201           #endif
 202
 203           test (relative_pwd_prog);
 204         }
 205     }
 206
 207   return 0;
 208 }