support/tst-support_capture_subprocess.c

   1 /* Test capturing output from a subprocess.
   2    Copyright (C) 2017-2018 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdbool.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <support/capture_subprocess.h>
  24 #include <support/check.h>
  25 #include <support/support.h>
  26 #include <sys/wait.h>
  27 #include <unistd.h>
  28
  29 /* Write one byte at *P to FD and advance *P.  Do nothing if *P is
  30    '\0'.  */
  31 static void
  32 transfer (const unsigned char **p, int fd)
  33 {
  34   if (**p != '\0')
  35     {
  36       TEST_VERIFY (write (fd, *p, 1) == 1);
  37       ++*p;
  38     }
  39 }
  40
  41 /* Determine the order in which stdout and stderr are written.  */
  42 enum write_mode { out_first, err_first, interleave,
  43                   write_mode_last =  interleave };
  44
  45 /* Describe what to write in the subprocess.  */
  46 struct test
  47 {
  48   char *out;
  49   char *err;
  50   enum write_mode write_mode;
  51   int signal;
  52   int status;
  53 };
  54
  55 /* For use with support_capture_subprocess.  */
  56 static void
  57 callback (void *closure)
  58 {
  59   const struct test *test = closure;
  60   bool mode_ok = false;
  61   switch (test->write_mode)
  62     {
  63     case out_first:
  64       TEST_VERIFY (fputs (test->out, stdout) >= 0);
  65       TEST_VERIFY (fflush (stdout) == 0);
  66       TEST_VERIFY (fputs (test->err, stderr) >= 0);
  67       TEST_VERIFY (fflush (stderr) == 0);
  68       mode_ok = true;
  69       break;
  70     case err_first:
  71       TEST_VERIFY (fputs (test->err, stderr) >= 0);
  72       TEST_VERIFY (fflush (stderr) == 0);
  73       TEST_VERIFY (fputs (test->out, stdout) >= 0);
  74       TEST_VERIFY (fflush (stdout) == 0);
  75       mode_ok = true;
  76       break;
  77     case interleave:
  78       {
  79         const unsigned char *pout = (const unsigned char *) test->out;
  80         const unsigned char *perr = (const unsigned char *) test->err;
  81         do
  82           {
  83             transfer (&pout, STDOUT_FILENO);
  84             transfer (&perr, STDERR_FILENO);
  85           }
  86         while (*pout != '\0' || *perr != '\0');
  87       }
  88       mode_ok = true;
  89       break;
  90     }
  91   TEST_VERIFY (mode_ok);
  92
  93   if (test->signal != 0)
  94     raise (test->signal);
  95   exit (test->status);
  96 }
  97
  98 /* Create a heap-allocated random string of letters.  */
  99 static char *
 100 random_string (size_t length)
 101 {
 102   char *result = xmalloc (length + 1);
 103   for (size_t i = 0; i < length; ++i)
 104     result[i] = 'a' + (rand () % 26);
 105   result[length] = '\0';
 106   return result;
 107 }
 108
 109 /* Check that the specific stream from the captured subprocess matches
 110    expectations.  */
 111 static void
 112 check_stream (const char *what, const struct xmemstream *stream,
 113               const char *expected)
 114 {
 115   if (strcmp (stream->buffer, expected) != 0)
 116     {
 117       support_record_failure ();
 118       printf ("error: captured %s data incorrect\n"
 119               "  expected: %s\n"
 120               "  actual:   %s\n",
 121               what, expected, stream->buffer);
 122     }
 123   if (stream->length != strlen (expected))
 124     {
 125       support_record_failure ();
 126       printf ("error: captured %s data length incorrect\n"
 127               "  expected: %zu\n"
 128               "  actual:   %zu\n",
 129               what, strlen (expected), stream->length);
 130     }
 131 }
 132
 133 static int
 134 do_test (void)
 135 {
 136   const int lengths[] = {0, 1, 17, 512, 20000, -1};
 137
 138   /* Test multiple combinations of support_capture_subprocess.
 139
 140      length_idx_stdout: Index into the lengths array above,
 141        controls how many bytes are written by the subprocess to
 142        standard output.
 143      length_idx_stderr: Same for standard error.
 144      write_mode: How standard output and standard error writes are
 145        ordered.
 146      signal: Exit with no signal if zero, with SIGTERM if one.
 147      status: Process exit status: 0 if zero, 3 if one.  */
 148   for (int length_idx_stdout = 0; lengths[length_idx_stdout] >= 0;
 149        ++length_idx_stdout)
 150     for (int length_idx_stderr = 0; lengths[length_idx_stderr] >= 0;
 151          ++length_idx_stderr)
 152       for (int write_mode = 0; write_mode < write_mode_last; ++write_mode)
 153         for (int signal = 0; signal < 2; ++signal)
 154           for (int status = 0; status < 2; ++status)
 155             {
 156               struct test test =
 157                 {
 158                   .out = random_string (lengths[length_idx_stdout]),
 159                   .err = random_string (lengths[length_idx_stderr]),
 160                   .write_mode = write_mode,
 161                   .signal = signal * SIGTERM, /* 0 or SIGTERM.  */
 162                   .status = status * 3,       /* 0 or 3.  */
 163                 };
 164               TEST_VERIFY (strlen (test.out) == lengths[length_idx_stdout]);
 165               TEST_VERIFY (strlen (test.err) == lengths[length_idx_stderr]);
 166
 167               struct support_capture_subprocess result
 168                 = support_capture_subprocess (callback, &test);
 169               check_stream ("stdout", &result.out, test.out);
 170               check_stream ("stderr", &result.err, test.err);
 171               if (test.signal != 0)
 172                 {
 173                   TEST_VERIFY (WIFSIGNALED (result.status));
 174                   TEST_VERIFY (WTERMSIG (result.status) == test.signal);
 175                 }
 176               else
 177                 {
 178                   TEST_VERIFY (WIFEXITED (result.status));
 179                   TEST_VERIFY (WEXITSTATUS (result.status) == test.status);
 180                 }
 181               support_capture_subprocess_free (&result);
 182               free (test.out);
 183               free (test.err);
 184             }
 185   return 0;
 186 }
 187
 188 #include <support/test-driver.c>