path: root/support/tst-support_capture_subprocess.c

/* Test capturing output from a subprocess.
   Copyright (C) 2017-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/capture_subprocess.h>
#include <support/check.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <sys/wait.h>
#include <unistd.h>
#include <paths.h>
#include <getopt.h>
#include <limits.h>
#include <errno.h>
#include <array_length.h>

/* Nonzero if the program gets called via 'exec'.  */
static int restart;

/* Hold the four initial argument used to respawn the process.  */
static char *initial_argv[5];

/* Write one byte at *P to FD and advance *P.  Do nothing if *P is
   '\0'.  */
static void
transfer (const unsigned char **p, int fd)
{
  if (**p != '\0')
    {
      TEST_VERIFY (write (fd, *p, 1) == 1);
      ++*p;
    }
}

/* Determine the order in which stdout and stderr are written.  */
enum write_mode { out_first, err_first, interleave,
                  write_mode_last =  interleave };

static const char *
write_mode_to_str (enum write_mode mode)
{
  switch (mode)
    {
    case out_first:  return "out_first";
    case err_first:  return "err_first";
    case interleave: return "interleave";
    default:         return "write_mode_last";
    }
}

static enum write_mode
str_to_write_mode (const char *mode)
{
  if (strcmp (mode, "out_first") == 0)
    return out_first;
  else if (strcmp (mode, "err_first") == 0)
    return err_first;
  else if (strcmp (mode, "interleave") == 0)
    return interleave;
  return write_mode_last;
}

/* Describe what to write in the subprocess.  */
struct test
{
  char *out;
  char *err;
  enum write_mode write_mode;
  int signal;
  int status;
};

_Noreturn static void
test_common (const struct test *test)
{
  bool mode_ok = false;
  switch (test->write_mode)
    {
    case out_first:
      TEST_VERIFY (fputs (test->out, stdout) >= 0);
      TEST_VERIFY (fflush (stdout) == 0);
      TEST_VERIFY (fputs (test->err, stderr) >= 0);
      TEST_VERIFY (fflush (stderr) == 0);
      mode_ok = true;
      break;
    case err_first:
      TEST_VERIFY (fputs (test->err, stderr) >= 0);
      TEST_VERIFY (fflush (stderr) == 0);
      TEST_VERIFY (fputs (test->out, stdout) >= 0);
      TEST_VERIFY (fflush (stdout) == 0);
      mode_ok = true;
      break;
    case interleave:
      {
        const unsigned char *pout = (const unsigned char *) test->out;
        const unsigned char *perr = (const unsigned char *) test->err;
        do
          {
            transfer (&pout, STDOUT_FILENO);
            transfer (&perr, STDERR_FILENO);
          }
        while (*pout != '\0' || *perr != '\0');
      }
      mode_ok = true;
      break;
    }
  TEST_VERIFY (mode_ok);

  if (test->signal != 0)
    raise (test->signal);
  exit (test->status);
}

static int
parse_int (const char *str)
{
  char *endptr;
  long int ret;
  errno = 0;
  ret = strtol (str, &endptr, 10);
  TEST_COMPARE (errno, 0);
  TEST_VERIFY (ret >= 0 && ret <= INT_MAX);
  return ret;
}

/* For use with support_capture_subprogram.  */
_Noreturn static void
handle_restart (char *out, char *err, const char *write_mode,
		const char *signal, const char *status)
{
  struct test test =
    {
      out,
      err,
      str_to_write_mode (write_mode),
      parse_int (signal),
      parse_int (status