lttng_ivc/apps/gen_ust_events/gen-ust-events.c

   1 /*
   2  * Copyright (C) - 2012 David Goulet <dgoulet@efficios.com>
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License as published by the
   6  * Free Software Foundation; version 2.1 of the License.
   7  *
   8  * This library is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  16  */
  17
  18 #include <arpa/inet.h>
  19 #include <assert.h>
  20 #include <time.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <poll.h>
  24 #include <signal.h>
  25 #include <stdarg.h>
  26 #include <stdbool.h>
  27 #include <stdint.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <sys/mman.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34 #include <unistd.h>
  35
  36 #include "tp.h"
  37
  38 #define NSEC_PER_USEC 1000
  39 #define NSEC_PER_SEC 1000000000
  40
  41 static inline
  42 int64_t elapsed_time_ns(struct timespec *t1, struct timespec *t2)
  43 {
  44         struct timespec delta;
  45
  46         assert(t1 && t2);
  47         delta.tv_sec = t2->tv_sec - t1->tv_sec;
  48         delta.tv_nsec = t2->tv_nsec - t1->tv_nsec;
  49         return ((int64_t) NSEC_PER_SEC * (int64_t) delta.tv_sec) +
  50                         (int64_t) delta.tv_nsec;
  51 }
  52
  53 static inline
  54 int usleep_safe(useconds_t usec)
  55 {
  56         int ret = 0;
  57         struct timespec t1, t2;
  58         int64_t time_remaining_ns = (int64_t) usec * (int64_t) NSEC_PER_USEC;
  59
  60         ret = clock_gettime(CLOCK_MONOTONIC, &t1);
  61         if (ret) {
  62                 ret = -1;
  63                 perror("clock_gettime");
  64                 goto end;
  65         }
  66
  67         while (time_remaining_ns > 0) {
  68                 ret = usleep(time_remaining_ns / (int64_t) NSEC_PER_USEC);
  69                 if (ret && errno != EINTR) {
  70                         perror("usleep");
  71                         goto end;
  72                 }
  73
  74                 ret = clock_gettime(CLOCK_MONOTONIC, &t2);
  75                 if (ret) {
  76                         perror("clock_gettime");
  77                         goto end;
  78                 }
  79
  80                 time_remaining_ns -= elapsed_time_ns(&t1, &t2);
  81         }
  82 end:
  83         return ret;
  84 }
  85
  86 void create_file(const char *path)
  87 {
  88         static bool file_created = false;
  89         int ret;
  90
  91         if (!path || file_created) {
  92                 return;
  93         }
  94
  95         ret = creat(path, S_IRWXU);
  96         if (ret < 0) {
  97                 fprintf(stderr, "Failed to create file %s\n", path);
  98                 return;
  99         }
 100
 101         (void) close(ret);
 102         file_created = true;
 103 }
 104
 105 static
 106 void wait_on_file(const char *path)
 107 {
 108         if (!path) {
 109                 return;
 110         }
 111         for (;;) {
 112                 int ret;
 113                 struct stat buf;
 114
 115                 ret = stat(path, &buf);
 116                 if (ret == -1 && errno == ENOENT) {
 117                         (void) poll(NULL, 0, 10);       /* 10 ms delay */
 118                         continue;                       /* retry */
 119                 }
 120                 if (ret) {
 121                         perror("stat");
 122                         exit(EXIT_FAILURE);
 123                 }
 124                 break;  /* found */
 125         }
 126 }
 127
 128 int main(int argc, char **argv)
 129 {
 130         unsigned int i, netint;
 131         long values[] = { 1, 2, 3 };
 132         char text[10] = "test";
 133         double dbl = 2.0;
 134         float flt = 2222.0;
 135         int nr_iter = 100, ret = 0;
 136         useconds_t nr_usec = 0;
 137         char *after_first_event_file_path = NULL;
 138         char *before_last_event_file_path = NULL;
 139
 140         if (argc >= 2) {
 141                 /*
 142                  * If nr_iter is negative, do an infinite tracing loop.
 143                  */
 144                 nr_iter = atoi(argv[1]);
 145         }
 146
 147         if (argc >= 3) {
 148                 /* By default, don't wait unless user specifies. */
 149                 nr_usec = atoi(argv[2]);
 150         }
 151
 152         if (argc >= 4) {
 153                 after_first_event_file_path = argv[3];
 154         }
 155
 156         if (argc >= 5) {
 157                 before_last_event_file_path = argv[4];
 158         }
 159
 160         for (i = 0; nr_iter < 0 || i < nr_iter; i++) {
 161                 if (nr_iter >= 0 && i == nr_iter - 1) {
 162                         /*
 163                          * Wait on synchronization before writing last
 164                          * event.
 165                          */
 166                         wait_on_file(before_last_event_file_path);
 167                 }
 168                 netint = htonl(i);
 169                 tracepoint(tp, tptest, i, netint, values, text,
 170                         strlen(text), dbl, flt);
 171
 172                 /*
 173                  * First loop we create the file if asked to indicate
 174                  * that at least one tracepoint has been hit.
 175                  */
 176                 create_file(after_first_event_file_path);
 177                 if (nr_usec) {
 178                         if (usleep_safe(nr_usec)) {
 179                                 ret = -1;
 180                                 goto end;
 181                         }
 182                 }
 183         }
 184
 185 end:
 186         exit(!ret ? EXIT_SUCCESS : EXIT_FAILURE);
 187 }