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
  27 /*
  28  * Write to writable pipe used to notify a thread.
  29  */
  30 int notify_thread_pipe(int wpipe)
  31 {
  32         int ret;
  33
  34         /* Ignore if the pipe is invalid. */
  35         if (wpipe < 0) {
  36                 return 0;
  37         }
  38
  39         do {
  40                 ret = write(wpipe, "!", 1);
  41         } while (ret < 0 && errno == EINTR);
  42         if (ret < 0) {
  43                 PERROR("write poll pipe");
  44         }
  45
  46         return ret;
  47 }
  48
  49 /*
  50  * Return pointer to home directory path using the env variable HOME.
  51  *
  52  * No home, NULL is returned.
  53  */
  54 const char *get_home_dir(void)
  55 {
  56         return ((const char *) getenv("HOME"));
  57 }