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38eb8a68 FD |
1 | /* |
2 | * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
3 | * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com> | |
4 | * | |
5 | * SPDX-License-Identifier: GPL-2.0-only | |
6 | * | |
7 | */ | |
8 | ||
9 | #include <common/compat/getenv.h> | |
10 | #include <common/consumer/consumer.h> | |
11 | #include <common/pipe.h> | |
12 | #include <common/error.h> | |
13 | #include <unistd.h> | |
14 | #include <stdbool.h> | |
15 | #include <lttng/constant.h> | |
16 | #include <fcntl.h> | |
17 | #include <dlfcn.h> | |
38eb8a68 FD |
18 | #include <stdio.h> |
19 | ||
20 | static char *pause_pipe_path; | |
21 | static struct lttng_pipe *pause_pipe; | |
22 | static int *notifier_notif_consumption_state;; | |
23 | ||
24 | int lttng_opt_verbose; | |
25 | int lttng_opt_mi; | |
26 | int lttng_opt_quiet; | |
27 | ||
28 | static | |
29 | void __attribute__((destructor)) pause_pipe_fini(void) | |
30 | { | |
31 | int ret; | |
32 | ||
33 | if (pause_pipe_path) { | |
34 | ret = unlink(pause_pipe_path); | |
35 | if (ret) { | |
36 | PERROR("Failed to unlink pause pipe: path = %s", | |
37 | pause_pipe_path); | |
38 | } | |
39 | } | |
40 | ||
41 | free(pause_pipe_path); | |
42 | lttng_pipe_destroy(pause_pipe); | |
43 | } | |
44 | ||
45 | int __testpoint_sessiond_thread_notification(void); | |
46 | int __testpoint_sessiond_thread_notification(void) | |
47 | { | |
48 | int ret = 0; | |
49 | const char *pause_pipe_path_prefix; | |
50 | ||
51 | pause_pipe_path_prefix = lttng_secure_getenv( | |
52 | "NOTIFIER_PAUSE_PIPE_PATH"); | |
53 | if (!pause_pipe_path_prefix) { | |
54 | ret = -1; | |
55 | goto end; | |
56 | } | |
57 | ||
58 | notifier_notif_consumption_state = dlsym(NULL, "notifier_consumption_paused"); | |
a0377dfe | 59 | LTTNG_ASSERT(notifier_notif_consumption_state); |
38eb8a68 FD |
60 | |
61 | ret = asprintf(&pause_pipe_path, "%s", pause_pipe_path_prefix); | |
62 | if (ret < 1) { | |
63 | ERR("Failed to allocate pause pipe path"); | |
64 | goto end; | |
65 | } | |
66 | ||
67 | DBG("Creating pause pipe at %s", pause_pipe_path); | |
68 | pause_pipe = lttng_pipe_named_open(pause_pipe_path, | |
69 | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP, O_NONBLOCK); | |
70 | if (!pause_pipe) { | |
71 | ERR("Failed to create pause pipe at %s", pause_pipe_path); | |
72 | ret = -1; | |
73 | goto end; | |
74 | } | |
75 | ||
76 | /* Only the read end of the pipe is useful to us. */ | |
77 | ret = lttng_pipe_write_close(pause_pipe); | |
78 | end: | |
79 | return ret; | |
80 | } | |
81 | ||
82 | int __testpoint_sessiond_handle_notifier_event_pipe(void); | |
83 | int __testpoint_sessiond_handle_notifier_event_pipe(void) | |
84 | { | |
85 | int ret = 0; | |
86 | uint8_t value; | |
87 | bool value_read = false; | |
88 | ||
89 | if (!pause_pipe) { | |
90 | ret = -1; | |
91 | goto end; | |
92 | } | |
93 | ||
94 | /* Purge pipe and only consider the freshest value. */ | |
95 | do { | |
96 | ret = lttng_pipe_read(pause_pipe, &value, sizeof(value)); | |
97 | if (ret == sizeof(value)) { | |
98 | value_read = true; | |
99 | } | |
100 | } while (ret == sizeof(value)); | |
101 | ||
102 | ret = (errno == EAGAIN) ? 0 : -errno; | |
103 | ||
104 | if (value_read) { | |
105 | *notifier_notif_consumption_state = !!value; | |
106 | DBG("Message received on pause pipe: %s data consumption", | |
107 | *notifier_notif_consumption_state ? "paused" : "resumed"); | |
108 | } | |
109 | end: | |
110 | return ret; | |
111 | } |