2 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
8 #include <common/compat/getenv.h>
9 #include <common/consumer/consumer.h>
10 #include <common/pipe.h>
11 #include <common/error.h>
14 #include <lttng/constant.h>
20 static char *pause_pipe_path
;
21 static struct lttng_pipe
*pause_pipe
;
22 static int *data_consumption_state
;
23 static enum lttng_consumer_type (*lttng_consumer_get_type
)(void);
25 int lttng_opt_verbose
;
30 void __attribute__((destructor
)) pause_pipe_fini(void)
34 if (pause_pipe_path
) {
35 ret
= unlink(pause_pipe_path
);
37 PERROR("unlink pause pipe");
41 free(pause_pipe_path
);
42 lttng_pipe_destroy(pause_pipe
);
46 * We use this testpoint, invoked at the start of the consumerd's data handling
47 * thread to create a named pipe/FIFO which a test application can use to either
48 * pause or resume the consumption of data.
50 int __testpoint_consumerd_thread_data(void);
51 int __testpoint_consumerd_thread_data(void)
54 const char *pause_pipe_path_prefix
, *domain
;
56 pause_pipe_path_prefix
= lttng_secure_getenv(
57 "CONSUMER_PAUSE_PIPE_PATH");
58 if (!pause_pipe_path_prefix
) {
64 * These symbols are exclusive to the consumerd process, hence we can't
65 * rely on their presence in the sessiond. Not looking-up these symbols
66 * dynamically would not allow this shared object to be LD_PRELOAD-ed
67 * when launching the session daemon.
69 data_consumption_state
= dlsym(NULL
, "data_consumption_paused");
70 assert(data_consumption_state
);
71 lttng_consumer_get_type
= dlsym(NULL
, "lttng_consumer_get_type");
72 assert(lttng_consumer_get_type
);
74 switch (lttng_consumer_get_type()) {
75 case LTTNG_CONSUMER_KERNEL
:
78 case LTTNG_CONSUMER32_UST
:
81 case LTTNG_CONSUMER64_UST
:
88 ret
= asprintf(&pause_pipe_path
, "%s-%s", pause_pipe_path_prefix
,
91 ERR("Failed to allocate pause pipe path");
95 DBG("Creating pause pipe at %s", pause_pipe_path
);
96 pause_pipe
= lttng_pipe_named_open(pause_pipe_path
,
97 S_IRUSR
| S_IWUSR
| S_IRGRP
| S_IWGRP
, O_NONBLOCK
);
99 ERR("Failed to create pause pipe at %s", pause_pipe_path
);
104 /* Only the read end of the pipe is useful to us. */
105 ret
= lttng_pipe_write_close(pause_pipe
);
110 int __testpoint_consumerd_thread_data_poll(void);
111 int __testpoint_consumerd_thread_data_poll(void)
115 bool value_read
= false;
122 /* Purge pipe and only consider the freshest value. */
124 ret
= lttng_pipe_read(pause_pipe
, &value
, sizeof(value
));
125 if (ret
== sizeof(value
)) {
128 } while (ret
== sizeof(value
));
130 ret
= (errno
== EAGAIN
) ? 0 : -errno
;
133 *data_consumption_state
= !!value
;
134 DBG("Message received on pause pipe: %s data consumption",
135 *data_consumption_state
? "paused" : "resumed");
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