posix/tst-exec.c

   1 /* Tests for exec.
   2    Copyright (C) 2000-2023 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 <error.h>
  21 #include <fcntl.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <wait.h>
  26
  27
  28 /* Nonzero if the program gets called via `exec'.  */
  29 static int restart;
  30
  31
  32 #define CMDLINE_OPTIONS \
  33   { "restart", no_argument, &restart, 1 },
  34
  35 /* Prototype for our test function.  */
  36 extern void do_prepare (int argc, char *argv[]);
  37 extern int do_test (int argc, char *argv[]);
  38
  39 /* We have a preparation function.  */
  40 #define PREPARE do_prepare
  41
  42 #include "../test-skeleton.c"
  43
  44
  45 /* Name of the temporary files.  */
  46 static char *name1;
  47 static char *name2;
  48
  49 /* File descriptors for these temporary files.  */
  50 static int temp_fd1 = -1;
  51 static int temp_fd2 = -1;
  52
  53 /* The contents of our files.  */
  54 static const char fd1string[] = "This file should get closed";
  55 static const char fd2string[] = "This file should stay opened";
  56
  57
  58 /* We have a preparation function.  */
  59 void
  60 do_prepare (int argc, char *argv[])
  61 {
  62   /* We must not open any files in the restart case.  */
  63   if (restart)
  64     return;
  65
  66   temp_fd1 = create_temp_file ("exec", &name1);
  67   temp_fd2 = create_temp_file ("exec", &name2);
  68   if (temp_fd1 < 0 || temp_fd2 < 0)
  69     exit (1);
  70 }
  71
  72
  73 static int
  74 handle_restart (const char *fd1s, const char *fd2s, const char *name)
  75 {
  76   char buf[100];
  77   int fd1;
  78   int fd2;
  79
  80   /* First get the descriptors.  */
  81   fd1 = atol (fd1s);
  82   fd2 = atol (fd2s);
  83
  84   /* Sanity check.  */
  85   if (fd1 == fd2)
  86     error (EXIT_FAILURE, 0, "value of fd1 and fd2 is the same");
  87
  88   /* First the easy part: read from the file descriptor which is
  89      supposed to be open.  */
  90   if (lseek (fd2, 0, SEEK_CUR) != strlen (fd2string))
  91     error (EXIT_FAILURE, errno, "file 2 not in right position");
  92   if (lseek (fd2, 0, SEEK_SET) != 0)
  93     error (EXIT_FAILURE, 0, "cannot reset position in file 2");
  94   if (read (fd2, buf, sizeof buf) != strlen (fd2string))
  95     error (EXIT_FAILURE, 0, "cannot read file 2");
  96   if (memcmp (fd2string, buf, strlen (fd2string)) != 0)
  97     error (EXIT_FAILURE, 0, "file 2 does not match");
  98
  99   /* No try to read the first file.  First make sure it is not opened.  */
 100   if (lseek (fd1, 0, SEEK_CUR) != (off_t) -1 || errno != EBADF)
 101     error (EXIT_FAILURE, 0, "file 1 (%d) is not closed", fd1);
 102
 103   /* Now open the file and read it.  */
 104   fd1 = open (name, O_RDONLY);
 105   if (fd1 == -1)
 106     error (EXIT_FAILURE, errno,
 107            "cannot open first file \"%s\" for verification", name);
 108
 109   if (read (fd1, buf, sizeof buf) != strlen (fd1string))
 110     error (EXIT_FAILURE, errno, "cannot read file 1");
 111   if (memcmp (fd1string, buf, strlen (fd1string)) != 0)
 112     error (EXIT_FAILURE, 0, "file 1 does not match");
 113
 114   return 0;
 115 }
 116
 117
 118 int
 119 do_test (int argc, char *argv[])
 120 {
 121   pid_t pid;
 122   int flags;
 123   int status;
 124
 125   /* We must have
 126      - one or four parameters left if called initially
 127        + path for ld.so         optional
 128        + "--library-path"       optional
 129        + the library path       optional
 130        + the application name
 131      - three parameters left if called through re-execution
 132        + file descriptor number which is supposed to be closed
 133        + the open file descriptor
 134        + the name of the closed descriptor
 135   */
 136
 137   if (restart)
 138     {
 139       if (argc != 4)
 140         error (EXIT_FAILURE, 0, "wrong number of arguments (%d)", argc);
 141
 142       return handle_restart (argv[1], argv[2], argv[3]);
 143     }
 144
 145   if (argc != 2 && argc != 5)
 146     error (EXIT_FAILURE, 0, "wrong number of arguments (%d)", argc);
 147
 148   /* Prepare the test.  We are creating two files: one which file descriptor
 149      will be marked with FD_CLOEXEC, another which is not.  */
 150
 151    /* Set the bit.  */
 152    flags = fcntl (temp_fd1, F_GETFD, 0);
 153    if (flags < 0)
 154      error (EXIT_FAILURE, errno, "cannot get flags");
 155    flags |= FD_CLOEXEC;
 156    if (fcntl (temp_fd1, F_SETFD, flags) < 0)
 157      error (EXIT_FAILURE, errno, "cannot set flags");
 158
 159    /* Write something in the files.  */
 160    if (write (temp_fd1, fd1string, strlen (fd1string)) != strlen (fd1string))
 161      error (EXIT_FAILURE, errno, "cannot write to first file");
 162    if (write (temp_fd2, fd2string, strlen (fd2string)) != strlen (fd2string))
 163      error (EXIT_FAILURE, errno, "cannot write to second file");
 164
 165   /* We want to test the `exec' function.  To do this we restart the program
 166      with an additional parameter.  But first create another process.  */
 167   pid = fork ();
 168   if (pid == 0)
 169     {
 170       char fd1name[18];
 171       char fd2name[18];
 172
 173       snprintf (fd1name, sizeof fd1name, "%d", temp_fd1);
 174       snprintf (fd2name, sizeof fd2name, "%d", temp_fd2);
 175
 176       /* This is the child.  Construct the command line.  */
 177       if (argc == 5)
 178         execl (argv[1], argv[1], argv[2], argv[3], argv[4], "--direct",
 179                "--restart", fd1name, fd2name, name1, NULL);
 180       else
 181         execl (argv[1], argv[1], "--direct",
 182                "--restart", fd1name, fd2name, name1, NULL);
 183
 184       error (EXIT_FAILURE, errno, "cannot exec");
 185     }
 186   else if (pid == (pid_t) -1)
 187     error (EXIT_FAILURE, errno, "cannot fork");
 188
 189   /* Wait for the child.  */
 190   if (waitpid (pid, &status, 0) != pid)
 191     error (EXIT_FAILURE, errno, "wrong child");
 192
 193   if (WTERMSIG (status) != 0)
 194     error (EXIT_FAILURE, 0, "Child terminated incorrectly");
 195   status = WEXITSTATUS (status);
 196
 197   return status;
 198 }