1/* Capture output from a subprocess.
2 Copyright (C) 2017-2020 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#include <support/subprocess.h>
20#include <support/capture_subprocess.h>
21
22#include <errno.h>
23#include <stdlib.h>
24#include <support/check.h>
25#include <support/xunistd.h>
26#include <support/xsocket.h>
27#include <support/xspawn.h>
28
29static void
30transfer (const char *what, struct pollfd *pfd, struct xmemstream *stream)
31{
32 if (pfd->revents != 0)
33 {
34 char buf[1024];
35 ssize_t ret = TEMP_FAILURE_RETRY (read (pfd->fd, buf, sizeof (buf)));
36 if (ret < 0)
37 {
38 support_record_failure ();
39 printf ("error: reading from subprocess %s: %m", what);
40 pfd->events = 0;
41 pfd->revents = 0;
42 }
43 else if (ret == 0)
44 {
45 /* EOF reached. Stop listening. */
46 pfd->events = 0;
47 pfd->revents = 0;
48 }
49 else
50 /* Store the data just read. */
51 TEST_VERIFY (fwrite (buf, ret, 1, stream->out) == 1);
52 }
53}
54
55static void
56support_capture_poll (struct support_capture_subprocess *result,
57 struct support_subprocess *proc)
58{
59 struct pollfd fds[2] =
60 {
61 { .fd = proc->stdout_pipe[0], .events = POLLIN },
62 { .fd = proc->stderr_pipe[0], .events = POLLIN },
63 };
64
65 do
66 {
67 xpoll (fds, 2, -1);
68 transfer ("stdout", &fds[0], &result->out);
69 transfer ("stderr", &fds[1], &result->err);
70 }
71 while (fds[0].events != 0 || fds[1].events != 0);
72
73 xfclose_memstream (&result->out);
74 xfclose_memstream (&result->err);
75
76 result->status = support_process_wait (proc);
77}
78
79struct support_capture_subprocess
80support_capture_subprocess (void (*callback) (void *), void *closure)
81{
82 struct support_capture_subprocess result;
83 xopen_memstream (&result.out);
84 xopen_memstream (&result.err);
85
86 struct support_subprocess proc = support_subprocess (callback, closure);
87
88 support_capture_poll (&result, &proc);
89 return result;
90}
91
92struct support_capture_subprocess
93support_capture_subprogram (const char *file, char *const argv[])
94{
95 struct support_capture_subprocess result;
96 xopen_memstream (&result.out);
97 xopen_memstream (&result.err);
98
99 struct support_subprocess proc = support_subprogram (file, argv);
100
101 support_capture_poll (&result, &proc);
102 return result;
103}
104
105void
106support_capture_subprocess_free (struct support_capture_subprocess *p)
107{
108 free (p->out.buffer);
109 free (p->err.buffer);
110}
111