Tests: add kernel snapshot streaming to root regression
[lttng-tools.git] / src / bin / lttng-sessiond / utils.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _GNU_SOURCE
20 #include <stdlib.h>
21 #include <unistd.h>
22
23 #include <common/error.h>
24
25 #include "utils.h"
26 #include "lttng-sessiond.h"
27
28 int ht_cleanup_pipe[2] = { -1, -1 };
29
30 /*
31 * Write to writable pipe used to notify a thread.
32 */
33 int notify_thread_pipe(int wpipe)
34 {
35 int ret;
36
37 /* Ignore if the pipe is invalid. */
38 if (wpipe < 0) {
39 return 0;
40 }
41
42 do {
43 ret = write(wpipe, "!", 1);
44 } while (ret < 0 && errno == EINTR);
45 if (ret < 0) {
46 PERROR("write poll pipe");
47 }
48
49 return ret;
50 }
51
52 void ht_cleanup_push(struct lttng_ht *ht)
53 {
54 int ret;
55 int fd = ht_cleanup_pipe[1];
56
57 if (fd < 0)
58 return;
59 do {
60 ret = write(fd, &ht, sizeof(ht));
61 } while (ret < 0 && errno == EINTR);
62 if (ret < 0 || ret != sizeof(ht)) {
63 PERROR("write ht cleanup pipe %d", fd);
64 if (ret < 0) {
65 ret = -errno;
66 }
67 goto error;
68 }
69
70 /* All good. Don't send back the write positive ret value. */
71 ret = 0;
72 error:
73 assert(!ret);
74 }
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