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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> | |
4bd69c5f | 16 | #include <lttng/lttng-export.h> |
38eb8a68 FD |
17 | #include <fcntl.h> |
18 | #include <dlfcn.h> | |
38eb8a68 FD |
19 | #include <stdio.h> |
20 | ||
21 | static char *pause_pipe_path; | |
22 | static struct lttng_pipe *pause_pipe; | |
23 | static int *notifier_notif_consumption_state;; | |
24 | ||
25 | int lttng_opt_verbose; | |
26 | int lttng_opt_mi; | |
27 | int lttng_opt_quiet; | |
28 | ||
29 | static | |
30 | void __attribute__((destructor)) pause_pipe_fini(void) | |
31 | { | |
32 | int ret; | |
33 | ||
34 | if (pause_pipe_path) { | |
35 | ret = unlink(pause_pipe_path); | |
36 | if (ret) { | |
37 | PERROR("Failed to unlink pause pipe: path = %s", | |
38 | pause_pipe_path); | |
39 | } | |
40 | } | |
41 | ||
42 | free(pause_pipe_path); | |
43 | lttng_pipe_destroy(pause_pipe); | |
44 | } | |
45 | ||
97535efa | 46 | extern "C" LTTNG_EXPORT int __testpoint_sessiond_thread_notification(void); |
38eb8a68 FD |
47 | int __testpoint_sessiond_thread_notification(void) |
48 | { | |
49 | int ret = 0; | |
50 | const char *pause_pipe_path_prefix; | |
51 | ||
52 | pause_pipe_path_prefix = lttng_secure_getenv( | |
53 | "NOTIFIER_PAUSE_PIPE_PATH"); | |
54 | if (!pause_pipe_path_prefix) { | |
55 | ret = -1; | |
56 | goto end; | |
57 | } | |
58 | ||
97535efa | 59 | notifier_notif_consumption_state = (int *) dlsym(NULL, "notifier_consumption_paused"); |
a0377dfe | 60 | LTTNG_ASSERT(notifier_notif_consumption_state); |
38eb8a68 FD |
61 | |
62 | ret = asprintf(&pause_pipe_path, "%s", pause_pipe_path_prefix); | |
63 | if (ret < 1) { | |
64 | ERR("Failed to allocate pause pipe path"); | |
65 | goto end; | |
66 | } | |
67 | ||
68 | DBG("Creating pause pipe at %s", pause_pipe_path); | |
69 | pause_pipe = lttng_pipe_named_open(pause_pipe_path, | |
70 | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP, O_NONBLOCK); | |
71 | if (!pause_pipe) { | |
72 | ERR("Failed to create pause pipe at %s", pause_pipe_path); | |
73 | ret = -1; | |
74 | goto end; | |
75 | } | |
76 | ||
77 | /* Only the read end of the pipe is useful to us. */ | |
78 | ret = lttng_pipe_write_close(pause_pipe); | |
79 | end: | |
80 | return ret; | |
81 | } | |
82 | ||
97535efa | 83 | extern "C" LTTNG_EXPORT int __testpoint_sessiond_handle_notifier_event_pipe(void); |
38eb8a68 FD |
84 | int __testpoint_sessiond_handle_notifier_event_pipe(void) |
85 | { | |
86 | int ret = 0; | |
87 | uint8_t value; | |
88 | bool value_read = false; | |
89 | ||
90 | if (!pause_pipe) { | |
91 | ret = -1; | |
92 | goto end; | |
93 | } | |
94 | ||
95 | /* Purge pipe and only consider the freshest value. */ | |
96 | do { | |
97 | ret = lttng_pipe_read(pause_pipe, &value, sizeof(value)); | |
98 | if (ret == sizeof(value)) { | |
99 | value_read = true; | |
100 | } | |
101 | } while (ret == sizeof(value)); | |
102 | ||
103 | ret = (errno == EAGAIN) ? 0 : -errno; | |
104 | ||
105 | if (value_read) { | |
106 | *notifier_notif_consumption_state = !!value; | |
107 | DBG("Message received on pause pipe: %s data consumption", | |
108 | *notifier_notif_consumption_state ? "paused" : "resumed"); | |
109 | } | |
110 | end: | |
111 | return ret; | |
112 | } |