tests/regression/tools/notification/consumer_testpoints.c

   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.h>
   9 #include <common/consumer/consumer.h>
  10 #include <common/pipe.h>
  11 #include <common/error.h>
  12 #include <unistd.h>
  13 #include <stdbool.h>
  14 #include <lttng/constant.h>
  15 #include <fcntl.h>
  16 #include <dlfcn.h>
  17 #include <assert.h>
  18 #include <stdio.h>
  19
  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);
  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("unlink pause pipe");
  38                 }
  39         }
  40
  41         free(pause_pipe_path);
  42         lttng_pipe_destroy(pause_pipe);
  43 }
  44
  45 /*
  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.
  49  */
  50 int __testpoint_consumerd_thread_data(void)
  51 {
  52         int ret = 0;
  53         const char *pause_pipe_path_prefix, *domain;
  54
  55         pause_pipe_path_prefix = lttng_secure_getenv(
  56                         "CONSUMER_PAUSE_PIPE_PATH");
  57         if (!pause_pipe_path_prefix) {
  58                 ret = -1;
  59                 goto end;
  60         }
  61
  62         /*
  63          * These symbols are exclusive to the consumerd process, hence we can't
  64          * rely on their presence in the sessiond. Not looking-up these symbols
  65          * dynamically would not allow this shared object to be LD_PRELOAD-ed
  66          * when launching the session daemon.
  67          */
  68         data_consumption_state = dlsym(NULL, "data_consumption_paused");
  69         assert(data_consumption_state);
  70         lttng_consumer_get_type = dlsym(NULL, "lttng_consumer_get_type");
  71         assert(lttng_consumer_get_type);
  72
  73         switch (lttng_consumer_get_type()) {
  74         case LTTNG_CONSUMER_KERNEL:
  75                 domain = "kernel";
  76                 break;
  77         case LTTNG_CONSUMER32_UST:
  78                 domain = "ust32";
  79                 break;
  80         case LTTNG_CONSUMER64_UST:
  81                 domain = "ust64";
  82                 break;
  83         default:
  84                 abort();
  85         }
  86
  87         ret = asprintf(&pause_pipe_path, "%s-%s", pause_pipe_path_prefix,
  88                         domain);
  89         if (ret < 1) {
  90                 ERR("Failed to allocate pause pipe path");
  91                 goto end;
  92         }
  93
  94         DBG("Creating pause pipe at %s", pause_pipe_path);
  95         pause_pipe = lttng_pipe_named_open(pause_pipe_path,
  96                         S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP, O_NONBLOCK);
  97         if (!pause_pipe) {
  98                 ERR("Failed to create pause pipe at %s", pause_pipe_path);
  99                 ret = -1;
 100                 goto end;
 101         }
 102
 103         /* Only the read end of the pipe is useful to us. */
 104         ret = lttng_pipe_write_close(pause_pipe);
 105 end:
 106         return ret;
 107 }
 108
 109 int __testpoint_consumerd_thread_data_poll(void)
 110 {
 111         int ret = 0;
 112         uint8_t value;
 113         bool value_read = false;
 114
 115         if (!pause_pipe) {
 116                 ret = -1;
 117                 goto end;
 118         }
 119
 120         /* Purge pipe and only consider the freshest value. */
 121         do {
 122                 ret = lttng_pipe_read(pause_pipe, &value, sizeof(value));
 123                 if (ret == sizeof(value)) {
 124                         value_read = true;
 125                 }
 126         } while (ret == sizeof(value));
 127
 128         ret = (errno == EAGAIN) ? 0 : -errno;
 129
 130         if (value_read) {
 131                 *data_consumption_state = !!value;
 132                 DBG("Message received on pause pipe: %s data consumption",
 133                                 *data_consumption_state ? "paused" : "resumed");
 134         }
 135 end:
 136         return ret;
 137 }