1 /* Capture output from a subprocess.
2    Copyright (C) 2017-2022 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    <https://www.gnu.org/licenses/>.  */
18 
19 #ifndef SUPPORT_CAPTURE_SUBPROCESS_H
20 #define SUPPORT_CAPTURE_SUBPROCESS_H
21 
22 #include <support/xmemstream.h>
23 
24 struct support_capture_subprocess
25 {
26   struct xmemstream out;
27   struct xmemstream err;
28   int status;
29 };
30 
31 /* Invoke CALLBACK (CLOSURE) in a subprocess and capture standard
32    output, standard error, and the exit status.  The out.buffer and
33    err.buffer members in the result are null-terminated strings which
34    can be examined by the caller (out.out and err.out are NULL).  */
35 struct support_capture_subprocess support_capture_subprocess
36   (void (*callback) (void *), void *closure);
37 
38 /* Issue FILE with ARGV arguments by using posix_spawn and capture standard
39    output, standard error, and the exit status.  The out.buffer and err.buffer
40    are handle as support_capture_subprocess.  */
41 struct support_capture_subprocess support_capture_subprogram
42   (const char *file, char *const argv[]);
43 
44 /* Copy the running program into a setgid binary and run it with CHILD_ID
45    argument.  If execution is successful, return the exit status of the child
46    program, otherwise return a non-zero failure exit code.  */
47 int support_capture_subprogram_self_sgid
48   (char *child_id);
49 
50 /* Deallocate the subprocess data captured by
51    support_capture_subprocess.  */
52 void support_capture_subprocess_free (struct support_capture_subprocess *);
53 
54 enum support_capture_allow
55 {
56   /* No output is allowed.  */
57   sc_allow_none = 0x01,
58   /* Output to stdout is permitted.  */
59   sc_allow_stdout = 0x02,
60   /* Output to standard error is permitted.  */
61   sc_allow_stderr = 0x04,
62 };
63 
64 /* Check that the subprocess exited and that only the allowed outputs
65    happened.  If STATUS_OR_SIGNAL is nonnegative, it is the expected
66    (decoded) exit status of the process, as returned by WEXITSTATUS.
67    If STATUS_OR_SIGNAL is negative, -STATUS_OR_SIGNAL is the expected
68    termination signal, as returned by WTERMSIG.  ALLOWED is a
69    combination of support_capture_allow flags.  Report errors under
70    the CONTEXT message.  */
71 void support_capture_subprocess_check (struct support_capture_subprocess *,
72                                        const char *context,
73                                        int status_or_signal, int allowed)
74   __attribute__ ((nonnull (1, 2)));
75 
76 #endif /* SUPPORT_CAPTURE_SUBPROCESS_H */
77