glibc/support/capture_subprocess.h
Siddhesh Poyarekar 716a3bdc41 support: Add capability to fork an sgid child
Add a new function support_capture_subprogram_self_sgid that spawns an
sgid child of the running program with its own image and returns the
exit code of the child process.  This functionality is used by at
least three tests in the testsuite at the moment, so it makes sense to
consolidate.

There is also a new function support_subprogram_wait which should
provide simple system() like functionality that does not set up file
actions.  This is useful in cases where only the return code of the
spawned subprocess is interesting.

This patch also ports tst-secure-getenv to this new function.  A
subsequent patch will port other tests.  This also brings an important
change to tst-secure-getenv behaviour.  Now instead of succeeding, the
test fails as UNSUPPORTED if it is unable to spawn a setgid child,
which is how it should have been in the first place.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-04-12 19:03:19 +05:30

77 lines
3.0 KiB
C

/* Capture 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/>. */
#ifndef SUPPORT_CAPTURE_SUBPROCESS_H
#define SUPPORT_CAPTURE_SUBPROCESS_H
#include <support/xmemstream.h>
struct support_capture_subprocess
{
struct xmemstream out;
struct xmemstream err;
int status;
};
/* Invoke CALLBACK (CLOSURE) in a subprocess and capture standard
output, standard error, and the exit status. The out.buffer and
err.buffer members in the result are null-terminated strings which
can be examined by the caller (out.out and err.out are NULL). */
struct support_capture_subprocess support_capture_subprocess
(void (*callback) (void *), void *closure);
/* Issue FILE with ARGV arguments by using posix_spawn and capture standard
output, standard error, and the exit status. The out.buffer and err.buffer
are handle as support_capture_subprocess. */
struct support_capture_subprocess support_capture_subprogram
(const char *file, char *const argv[]);
/* Copy the running program into a setgid binary and run it with CHILD_ID
argument. If execution is successful, return the exit status of the child
program, otherwise return a non-zero failure exit code. */
int support_capture_subprogram_self_sgid
(char *child_id);
/* Deallocate the subprocess data captured by
support_capture_subprocess. */
void support_capture_subprocess_free (struct support_capture_subprocess *);
enum support_capture_allow
{
/* No output is allowed. */
sc_allow_none = 0x01,
/* Output to stdout is permitted. */
sc_allow_stdout = 0x02,
/* Output to standard error is permitted. */
sc_allow_stderr = 0x04,
};
/* Check that the subprocess exited and that only the allowed outputs
happened. If STATUS_OR_SIGNAL is nonnegative, it is the expected
(decoded) exit status of the process, as returned by WEXITSTATUS.
If STATUS_OR_SIGNAL is negative, -STATUS_OR_SIGNAL is the expected
termination signal, as returned by WTERMSIG. ALLOWED is a
combination of support_capture_allow flags. Report errors under
the CONTEXT message. */
void support_capture_subprocess_check (struct support_capture_subprocess *,
const char *context,
int status_or_signal, int allowed)
__attribute__ ((nonnull (1, 2)));
#endif /* SUPPORT_CAPTURE_SUBPROCESS_H */