tests/regression/tools/notification/consumer_testpoints.cpp

   1 /*
   2  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #include <common/compat/getenv.hpp>
   9 #include <common/consumer/consumer.hpp>
  10 #include <common/error.hpp>
  11 #include <common/pipe.hpp>
  12
  13 #include <lttng/constant.h>
  14 #include <lttng/lttng-export.h>
  15
  16 #include <dlfcn.h>
  17 #include <fcntl.h>
  18 #include <stdbool.h>
  19 #include <stdio.h>
  20 #include <unistd.h>
  21
  22 static char *pause_pipe_path;
  23 static struct lttng_pipe *pause_pipe;
  24 static int *data_consumption_state;
  25 using lttng_consumer_get_type_func = enum lttng_consumer_type (*)();
  26 static lttng_consumer_get_type_func lttng_consumer_get_type;
  27
  28 int lttng_opt_verbose;
  29 int lttng_opt_mi;
  30 int lttng_opt_quiet;
  31
  32 static void __attribute__((destructor)) pause_pipe_fini()
  33 {
  34         int ret;
  35
  36         if (pause_pipe_path) {
  37                 ret = unlink(pause_pipe_path);
  38                 if (ret) {
  39                         PERROR("unlink pause pipe");
  40                 }
  41         }
  42
  43         free(pause_pipe_path);
  44         lttng_pipe_destroy(pause_pipe);
  45 }
  46
  47 /*
  48  * We use this testpoint, invoked at the start of the consumerd's data handling
  49  * thread to create a named pipe/FIFO which a test application can use to either
  50  * pause or resume the consumption of data.
  51  */
  52 extern "C" LTTNG_EXPORT int __testpoint_consumerd_thread_data(void);
  53 int __testpoint_consumerd_thread_data(void)
  54 {
  55         int ret = 0;
  56         const char *pause_pipe_path_prefix, *domain;
  57
  58         pause_pipe_path_prefix = lttng_secure_getenv("CONSUMER_PAUSE_PIPE_PATH");
  59         if (!pause_pipe_path_prefix) {
  60                 ret = -1;
  61                 goto end;
  62         }
  63
  64         /*
  65          * These symbols are exclusive to the consumerd process, hence we can't
  66          * rely on their presence in the sessiond. Not looking-up these symbols
  67          * dynamically would not allow this shared object to be LD_PRELOAD-ed
  68          * when launching the session daemon.
  69          */
  70         data_consumption_state = (int *) dlsym(nullptr, "data_consumption_paused");
  71         LTTNG_ASSERT(data_consumption_state);
  72         lttng_consumer_get_type =
  73                 (lttng_consumer_type(*)()) dlsym(nullptr, "lttng_consumer_get_type");
  74         LTTNG_ASSERT(lttng_consumer_get_type);
  75
  76         switch (lttng_consumer_get_type()) {
  77         case LTTNG_CONSUMER_KERNEL:
  78                 domain = "kernel";
  79                 break;
  80         case LTTNG_CONSUMER32_UST:
  81                 domain = "ust32";
  82                 break;
  83         case LTTNG_CONSUMER64_UST:
  84                 domain = "ust64";
  85                 break;
  86         default:
  87                 abort();
  88         }
  89
  90         ret = asprintf(&pause_pipe_path, "%s-%s", pause_pipe_path_prefix, domain);
  91         if (ret < 1) {
  92                 ERR("Failed to allocate pause pipe path");
  93                 goto end;
  94         }
  95
  96         DBG("Creating pause pipe at %s", pause_pipe_path);
  97         pause_pipe = lttng_pipe_named_open(
  98                 pause_pipe_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP, O_NONBLOCK);
  99         if (!pause_pipe) {
 100                 ERR("Failed to create pause pipe at %s", pause_pipe_path);
 101                 ret = -1;
 102                 goto end;
 103         }
 104
 105         /* Only the read end of the pipe is useful to us. */
 106         ret = lttng_pipe_write_close(pause_pipe);
 107 end:
 108         return ret;
 109 }
 110
 111 extern "C" LTTNG_EXPORT int __testpoint_consumerd_thread_data_poll(void);
 112 int __testpoint_consumerd_thread_data_poll(void)
 113 {
 114         int ret = 0;
 115         uint8_t value;
 116         bool value_read = false;
 117
 118         if (!pause_pipe) {
 119                 ret = -1;
 120                 goto end;
 121         }
 122
 123         /* Purge pipe and only consider the freshest value. */
 124         do {
 125                 ret = lttng_pipe_read(pause_pipe, &value, sizeof(value));
 126                 if (ret == sizeof(value)) {
 127                         value_read = true;
 128                 }
 129         } while (ret == sizeof(value));
 130
 131         ret = (errno == EAGAIN) ? 0 : -errno;
 132
 133         if (value_read) {
 134                 *data_consumption_state = !!value;
 135                 DBG("Message received on pause pipe: %s data consumption",
 136                     *data_consumption_state ? "paused" : "resumed");
 137         }
 138 end:
 139         return ret;
 140 }