src/bin/lttng-sessiond/utils.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22
  23 #include <common/error.h>
  24
  25 #include "utils.h"
  26 #include "lttng-sessiond.h"
  27
  28 int ht_cleanup_pipe[2] = { -1, -1 };
  29
  30 /*
  31  * Write to writable pipe used to notify a thread.
  32  */
  33 int notify_thread_pipe(int wpipe)
  34 {
  35         ssize_t ret;
  36
  37         /* Ignore if the pipe is invalid. */
  38         if (wpipe < 0) {
  39                 return 0;
  40         }
  41
  42         ret = lttng_write(wpipe, "!", 1);
  43         if (ret < 1) {
  44                 PERROR("write poll pipe");
  45         }
  46
  47         return (int) ret;
  48 }
  49
  50 void ht_cleanup_push(struct lttng_ht *ht)
  51 {
  52         ssize_t ret;
  53         int fd = ht_cleanup_pipe[1];
  54
  55         if (fd < 0)
  56                 return;
  57         ret = lttng_write(fd, &ht, sizeof(ht));
  58         if (ret < sizeof(ht)) {
  59                 PERROR("write ht cleanup pipe %d", fd);
  60                 if (ret < 0) {
  61                         ret = -errno;
  62                 }
  63                 goto error;
  64         }
  65
  66         /* All good. Don't send back the write positive ret value. */
  67         ret = 0;
  68 error:
  69         assert(!ret);
  70 }