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/* 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/capture_subprocess.h>
#include <errno.h>
#include <stdlib.h>
#include <support/check.h>
#include <support/xunistd.h>
#include <support/xsocket.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);
}
}
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);
int stdout_pipe[2];
xpipe (stdout_pipe);
TEST_VERIFY (stdout_pipe[0] > STDERR_FILENO);
TEST_VERIFY (stdout_pipe[1] > STDERR_FILENO);
int stderr_pipe[2];
xpipe (stderr_pipe);
TEST_VERIFY (stderr_pipe[0] > STDERR_FILENO);
TEST_VERIFY (stderr_pipe[1] > STDERR_FILENO);
TEST_VERIFY (fflush (stdout) == 0);
TEST_VERIFY (fflush (stderr) == 0);
pid_t pid = xfork ();
if (pid == 0)
{
xclose (stdout_pipe[0]);
xclose (stderr_pipe[0]);
xdup2 (stdout_pipe[1], STDOUT_FILENO);
xdup2 (stderr_pipe[1], STDERR_FILENO);
xclose (stdout_pipe[1]);
xclose (stderr_pipe[1]);
callback (closure);
_exit (0);
}
xclose (stdout_pipe[1]);
xclose (stderr_pipe[1]);
struct pollfd fds[2] =
{
{ .fd = stdout_pipe[0], .events = POLLIN },
{ .fd = 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);
xclose (stdout_pipe[0]);
xclose (stderr_pipe[0]);
xfclose_memstream (&result.out);
xfclose_memstream (&result.err);
xwaitpid (pid, &result.status, 0);
return result;
}
void
support_capture_subprocess_free (struct support_capture_subprocess *p)
{
free (p->out.buffer);
free (p->err.buffer);
}
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