posix/tst-posix_spawn-setsid.c

   1 /* Test posix_spawn setsid attribute.
   2    Copyright (C) 2017-2023 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 <errno.h>
  20 #include <fcntl.h>
  21 #include <getopt.h>
  22 #include <intprops.h>
  23 #include <paths.h>
  24 #include <spawn.h>
  25 #include <stdbool.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <sys/resource.h>
  29 #include <sys/wait.h>
  30 #include <unistd.h>
  31
  32 #include <support/check.h>
  33 #include <support/xunistd.h>
  34 #include <support/temp_file.h>
  35 #include <tst-spawn.h>
  36
  37 /* Nonzero if the program gets called via `exec'.  */
  38 static int restart;
  39
  40 /* Hold the four initial argument used to respawn the process, plus
  41    the extra '--direct' and '--restart', and a final NULL.  */
  42 static char *initial_argv[7];
  43 static int initial_argv_count;
  44
  45 #define CMDLINE_OPTIONS \
  46   { "restart", no_argument, &restart, 1 },
  47
  48 static char *pidfile;
  49
  50 static pid_t
  51 read_child_sid (void)
  52 {
  53   int pidfd = xopen (pidfile, O_RDONLY, 0);
  54
  55   char buf[INT_STRLEN_BOUND (pid_t)];
  56   ssize_t n = read (pidfd, buf, sizeof (buf));
  57   TEST_VERIFY (n < sizeof buf && n >= 0);
  58   buf[n] = '\0';
  59
  60   /* We only expect to read the PID.  */
  61   char *endp;
  62   long int rpid = strtol (buf, &endp, 10);
  63   TEST_VERIFY (endp != buf);
  64
  65   xclose (pidfd);
  66
  67   return rpid;
  68 }
  69
  70 /* Called on process re-execution, write down the session id on PIDFILE.  */
  71 static void
  72 handle_restart (const char *pidfile)
  73 {
  74   int pidfd = xopen (pidfile, O_WRONLY, 0);
  75
  76   char buf[INT_STRLEN_BOUND (pid_t)];
  77   int s = snprintf (buf, sizeof buf, "%d", getsid (0));
  78   size_t n = write (pidfd, buf, s);
  79   TEST_VERIFY (n == s);
  80
  81   xclose (pidfd);
  82 }
  83
  84 static void
  85 do_test_setsid (bool test_setsid)
  86 {
  87   /* Current session ID.  */
  88   pid_t sid = getsid (0);
  89   TEST_VERIFY (sid != (pid_t) -1);
  90
  91   posix_spawnattr_t attrp;
  92   TEST_COMPARE (posix_spawnattr_init (&attrp), 0);
  93   if (test_setsid)
  94     TEST_COMPARE (posix_spawnattr_setflags (&attrp, POSIX_SPAWN_SETSID), 0);
  95
  96   /* 1 or 4 elements from initial_argv:
  97        + path to ld.so          optional
  98        + --library-path         optional
  99        + the library path       optional
 100        + application name
 101        + --direct
 102        + --restart
 103        + pidfile  */
 104   int argv_size = initial_argv_count + 2;
 105   char *args[argv_size];
 106   int argc = 0;
 107
 108   for (char **arg = initial_argv; *arg != NULL; arg++)
 109     args[argc++] = *arg;
 110   args[argc++] = pidfile;
 111   args[argc] = NULL;
 112   TEST_VERIFY (argc < argv_size);
 113
 114   PID_T_TYPE pid;
 115   TEST_COMPARE (POSIX_SPAWN (&pid, args[0], NULL, &attrp, args, environ), 0);
 116   TEST_COMPARE (posix_spawnattr_destroy (&attrp), 0);
 117
 118   siginfo_t sinfo;
 119   TEST_COMPARE (WAITID (P_PID, pid, &sinfo, WEXITED), 0);
 120   TEST_COMPARE (sinfo.si_code, CLD_EXITED);
 121   TEST_COMPARE (sinfo.si_status, 0);
 122
 123   pid_t child_sid = read_child_sid ();
 124
 125   /* Child should have a different session ID than parent.  */
 126   TEST_VERIFY (child_sid != (pid_t) -1);
 127
 128   if (test_setsid)
 129     TEST_VERIFY (child_sid != sid);
 130   else
 131     TEST_VERIFY (child_sid == sid);
 132 }
 133
 134 static int
 135 do_test (int argc, char *argv[])
 136 {
 137   /* We must have either:
 138
 139      - one or four parameters if called initially:
 140        + argv[1]: path for ld.so        optional
 141        + argv[2]: "--library-path"      optional
 142        + argv[3]: the library path      optional
 143        + argv[4]: the application name
 144
 145      - six parameters left if called through re-execution:
 146        + argv[5/1]: the application name
 147        + argv[6/2]: the pidfile
 148
 149      * When built with --enable-hardcoded-path-in-tests or issued without
 150        using the loader directly.  */
 151
 152   if (restart)
 153     {
 154       handle_restart (argv[1]);
 155       return 0;
 156     }
 157
 158   TEST_VERIFY_EXIT (argc == 2 || argc == 5);
 159
 160   int i;
 161   for (i = 0; i < argc - 1; i++)
 162     initial_argv[i] = argv[i + 1];
 163   initial_argv[i++] = (char *) "--direct";
 164   initial_argv[i++] = (char *) "--restart";
 165   initial_argv_count = i;
 166
 167   create_temp_file ("tst-posix_spawn-setsid-", &pidfile);
 168
 169   do_test_setsid (false);
 170   do_test_setsid (true);
 171
 172   return 0;
 173 }
 174
 175 #define TEST_FUNCTION_ARGV do_test
 176 #include <support/test-driver.c>