/* Capture output from a subprocess.

   Copyright (C) 2017-2018 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

   <http://www.gnu.org/licenses/>.  */

#include <support/subprocess.h>

#include <support/capture_subprocess.h>

#include <errno.h>

#include <stdlib.h>

#include <support/check.h>

#include <support/xunistd.h>

#include <support/xsocket.h>

#include <support/xspawn.h>

static void

transfer (const char *what, struct pollfd *pfd, struct xmemstream *stream)

{

  if (pfd->revents != 0)

    {

      char buf[1024];

      ssize_t ret = TEMP_FAILURE_RETRY (read (pfd->fd, buf, sizeof (buf)));

      if (ret < 0)

        {

          support_record_failure ();

          printf ("error: reading from subprocess %s: %m", what);

          pfd->events = 0;

          pfd->revents = 0;

        }

      else if (ret == 0)

        {

          /* EOF reached.  Stop listening.  */

          pfd->events = 0;

          pfd->revents = 0;

        }

      else

        /* Store the data just read.   */

        TEST_VERIFY (fwrite (buf, ret, 1, stream->out) == 1);

    }

}

static void

support_capture_poll (struct support_capture_subprocess *result,

                     struct support_subprocess *proc)

{

  struct pollfd fds[2] =

    {

      { .fd = proc->stdout_pipe[0], .events = POLLIN },

      { .fd = proc->stderr_pipe[0], .events = POLLIN },

    };

  do

    {

      xpoll (fds, 2, -1);

      transfer ("stdout", &fds[0], &result->out);

      transfer ("stderr", &fds[1], &result->err);

    }

  while (fds[0].events != 0 || fds[1].events != 0);

  xfclose_memstream (&result->out);

  xfclose_memstream (&result->err);

  result->status = support_process_wait (proc);

}

struct support_capture_subprocess

support_capture_subprocess (void (*callback) (void *), void *closure)

{

  struct support_capture_subprocess result;

  xopen_memstream (&result.out);

  xopen_memstream (&result.err);

  struct support_subprocess proc = support_subprocess (callback, closure);

  support_capture_poll (&result, &proc;;

  return result;

}

struct support_capture_subprocess

support_capture_subprogram (const char *file, char *const argv[])

{

  struct support_capture_subprocess result;

  xopen_memstream (&result.out);

  xopen_memstream (&result.err);

  struct support_subprocess proc = support_subprogram (file, argv);

  support_capture_poll (&result, &proc;;

  return result;

}

void

support_capture_subprocess_free (struct support_capture_subprocess *p)

{

  free (p->out.buffer);

  free (p->err.buffer);

}