posix/tst-exec.c

   1 /* Tests for exec.
   2    Copyright (C) 2000-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <error.h>
  22 #include <fcntl.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <wait.h>
  27
  28
  29 /* Nonzero if the program gets called via `exec'.  */
  30 static int restart;
  31
  32
  33 #define CMDLINE_OPTIONS \
  34   { "restart", no_argument, &restart, 1 },
  35
  36 /* Prototype for our test function.  */
  37 extern void do_prepare (int argc, char *argv[]);
  38 extern int do_test (int argc, char *argv[]);
  39
  40 /* We have a preparation function.  */
  41 #define PREPARE do_prepare
  42
  43 #include "../test-skeleton.c"
  44
  45
  46 /* Name of the temporary files.  */
  47 static char *name1;
  48 static char *name2;
  49
  50 /* File descriptors for these temporary files.  */
  51 static int temp_fd1 = -1;
  52 static int temp_fd2 = -1;
  53
  54 /* The contents of our files.  */
  55 static const char fd1string[] = "This file should get closed";
  56 static const char fd2string[] = "This file should stay opened";
  57
  58
  59 /* We have a preparation function.  */
  60 void
  61 do_prepare (int argc, char *argv[])
  62 {
  63   /* We must not open any files in the restart case.  */
  64   if (restart)
  65     return;
  66
  67   temp_fd1 = create_temp_file ("exec", &name1);
  68   temp_fd2 = create_temp_file ("exec", &name2);
  69   if (temp_fd1 < 0 || temp_fd2 < 0)
  70     exit (1);
  71 }
  72
  73
  74 static int
  75 handle_restart (const char *fd1s, const char *fd2s, const char *name)
  76 {
  77   char buf[100];
  78   int fd1;
  79   int fd2;
  80
  81   /* First get the descriptors.  */
  82   fd1 = atol (fd1s);
  83   fd2 = atol (fd2s);
  84
  85   /* Sanity check.  */
  86   if (fd1 == fd2)
  87     error (EXIT_FAILURE, 0, "value of fd1 and fd2 is the same");
  88
  89   /* First the easy part: read from the file descriptor which is
  90      supposed to be open.  */
  91   if (lseek (fd2, 0, SEEK_CUR) != strlen (fd2string))
  92     error (EXIT_FAILURE, errno, "file 2 not in right position");
  93   if (lseek (fd2, 0, SEEK_SET) != 0)
  94     error (EXIT_FAILURE, 0, "cannot reset position in file 2");
  95   if (read (fd2, buf, sizeof buf) != strlen (fd2string))
  96     error (EXIT_FAILURE, 0, "cannot read file 2");
  97   if (memcmp (fd2string, buf, strlen (fd2string)) != 0)
  98     error (EXIT_FAILURE, 0, "file 2 does not match");
  99
 100   /* No try to read the first file.  First make sure it is not opened.  */
 101   if (lseek (fd1, 0, SEEK_CUR) != (off_t) -1 || errno != EBADF)
 102     error (EXIT_FAILURE, 0, "file 1 (%d) is not closed", fd1);
 103
 104   /* Now open the file and read it.  */
 105   fd1 = open (name, O_RDONLY);
 106   if (fd1 == -1)
 107     error (EXIT_FAILURE, errno,
 108            "cannot open first file \"%s\" for verification", name);
 109
 110   if (read (fd1, buf, sizeof buf) != strlen (fd1string))
 111     error (EXIT_FAILURE, errno, "cannot read file 1");
 112   if (memcmp (fd1string, buf, strlen (fd1string)) != 0)
 113     error (EXIT_FAILURE, 0, "file 1 does not match");
 114
 115   return 0;
 116 }
 117
 118
 119 int
 120 do_test (int argc, char *argv[])
 121 {
 122   pid_t pid;
 123   int flags;
 124   int status;
 125
 126   /* We must have
 127      - one or four parameters left if called initially
 128        + path for ld.so         optional
 129        + "--library-path"       optional
 130        + the library path       optional
 131        + the application name
 132      - three parameters left if called through re-execution
 133        + file descriptor number which is supposed to be closed
 134        + the open file descriptor
 135        + the name of the closed desriptor
 136   */
 137
 138   if (restart)
 139     {
 140       if (argc != 4)
 141         error (EXIT_FAILURE, 0, "wrong number of arguments (%d)", argc);
 142
 143       return handle_restart (argv[1], argv[2], argv[3]);
 144     }
 145
 146   if (argc != 2 && argc != 5)
 147     error (EXIT_FAILURE, 0, "wrong number of arguments (%d)", argc);
 148
 149   /* Prepare the test.  We are creating two files: one which file descriptor
 150      will be marked with FD_CLOEXEC, another which is not.  */
 151
 152    /* Set the bit.  */
 153    flags = fcntl (temp_fd1, F_GETFD, 0);
 154    if (flags < 0)
 155      error (EXIT_FAILURE, errno, "cannot get flags");
 156    flags |= FD_CLOEXEC;
 157    if (fcntl (temp_fd1, F_SETFD, flags) < 0)
 158      error (EXIT_FAILURE, errno, "cannot set flags");
 159
 160    /* Write something in the files.  */
 161    if (write (temp_fd1, fd1string, strlen (fd1string)) != strlen (fd1string))
 162      error (EXIT_FAILURE, errno, "cannot write to first file");
 163    if (write (temp_fd2, fd2string, strlen (fd2string)) != strlen (fd2string))
 164      error (EXIT_FAILURE, errno, "cannot write to second file");
 165
 166   /* We want to test the `exec' function.  To do this we restart the program
 167      with an additional parameter.  But first create another process.  */
 168   pid = fork ();
 169   if (pid == 0)
 170     {
 171       char fd1name[18];
 172       char fd2name[18];
 173
 174       snprintf (fd1name, sizeof fd1name, "%d", temp_fd1);
 175       snprintf (fd2name, sizeof fd2name, "%d", temp_fd2);
 176
 177       /* This is the child.  Construct the command line.  */
 178       if (argc == 5)
 179         execl (argv[1], argv[1], argv[2], argv[3], argv[4], "--direct",
 180                "--restart", fd1name, fd2name, name1, NULL);
 181       else
 182         execl (argv[1], argv[1], "--direct",
 183                "--restart", fd1name, fd2name, name1, NULL);
 184
 185       error (EXIT_FAILURE, errno, "cannot exec");
 186     }
 187   else if (pid == (pid_t) -1)
 188     error (EXIT_FAILURE, errno, "cannot fork");
 189
 190   /* Wait for the child.  */
 191   if (waitpid (pid, &status, 0) != pid)
 192     error (EXIT_FAILURE, errno, "wrong child");
 193
 194   if (WTERMSIG (status) != 0)
 195     error (EXIT_FAILURE, 0, "Child terminated incorrectly");
 196   status = WEXITSTATUS (status);
 197
 198   return status;
 199 }