1 | /* Capture output from a subprocess. |
2 | Copyright (C) 2017-2018 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 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <support/capture_subprocess.h> |
20 | |
21 | #include <errno.h> |
22 | #include <stdlib.h> |
23 | #include <support/check.h> |
24 | #include <support/xunistd.h> |
25 | #include <support/xsocket.h> |
26 | |
27 | static void |
28 | transfer (const char *what, struct pollfd *pfd, struct xmemstream *stream) |
29 | { |
30 | if (pfd->revents != 0) |
31 | { |
32 | char buf[1024]; |
33 | ssize_t ret = TEMP_FAILURE_RETRY (read (pfd->fd, buf, sizeof (buf))); |
34 | if (ret < 0) |
35 | { |
36 | support_record_failure (); |
37 | printf ("error: reading from subprocess %s: %m" , what); |
38 | pfd->events = 0; |
39 | pfd->revents = 0; |
40 | } |
41 | else if (ret == 0) |
42 | { |
43 | /* EOF reached. Stop listening. */ |
44 | pfd->events = 0; |
45 | pfd->revents = 0; |
46 | } |
47 | else |
48 | /* Store the data just read. */ |
49 | TEST_VERIFY (fwrite (buf, ret, 1, stream->out) == 1); |
50 | } |
51 | } |
52 | |
53 | struct support_capture_subprocess |
54 | support_capture_subprocess (void (*callback) (void *), void *closure) |
55 | { |
56 | struct support_capture_subprocess result; |
57 | xopen_memstream (&result.out); |
58 | xopen_memstream (&result.err); |
59 | |
60 | int stdout_pipe[2]; |
61 | xpipe (stdout_pipe); |
62 | int stderr_pipe[2]; |
63 | xpipe (stderr_pipe); |
64 | |
65 | TEST_VERIFY (fflush (stdout) == 0); |
66 | TEST_VERIFY (fflush (stderr) == 0); |
67 | |
68 | pid_t pid = xfork (); |
69 | if (pid == 0) |
70 | { |
71 | xclose (stdout_pipe[0]); |
72 | xclose (stderr_pipe[0]); |
73 | xdup2 (stdout_pipe[1], STDOUT_FILENO); |
74 | xdup2 (stderr_pipe[1], STDERR_FILENO); |
75 | callback (closure); |
76 | _exit (0); |
77 | } |
78 | xclose (stdout_pipe[1]); |
79 | xclose (stderr_pipe[1]); |
80 | |
81 | struct pollfd fds[2] = |
82 | { |
83 | { .fd = stdout_pipe[0], .events = POLLIN }, |
84 | { .fd = stderr_pipe[0], .events = POLLIN }, |
85 | }; |
86 | |
87 | do |
88 | { |
89 | xpoll (fds, 2, -1); |
90 | transfer ("stdout" , &fds[0], &result.out); |
91 | transfer ("stderr" , &fds[1], &result.err); |
92 | } |
93 | while (fds[0].events != 0 || fds[1].events != 0); |
94 | xclose (stdout_pipe[0]); |
95 | xclose (stderr_pipe[0]); |
96 | |
97 | xfclose_memstream (&result.out); |
98 | xfclose_memstream (&result.err); |
99 | xwaitpid (pid, &result.status, 0); |
100 | return result; |
101 | } |
102 | |
103 | void |
104 | support_capture_subprocess_free (struct support_capture_subprocess *p) |
105 | { |
106 | free (p->out.buffer); |
107 | free (p->err.buffer); |
108 | } |
109 | |