src/bin/lttng-sessiond/fd-limit.c

   1 /*
   2  * Copyright (C) 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <urcu/uatomic.h>
  20 #include <sys/time.h>
  21 #include <sys/resource.h>
  22 #include <errno.h>
  23 #include <stdio.h>
  24 #include "fd-limit.h"
  25 #include <common/error.h>
  26
  27 /* total count of fd. */
  28 static long fd_count;
  29
  30 /*
  31  * threshold in % of number of fd allowed.
  32  */
  33 static long fd_threshold[LTTNG_FD_NR_TYPES] = {
  34         [LTTNG_FD_APPS] = 75,
  35 };
  36
  37 static rlim_t max_nr_fd;
  38
  39 int lttng_fd_get(enum lttng_fd_type type, unsigned int nr)
  40 {
  41         long newval;
  42
  43         if (type >= LTTNG_FD_NR_TYPES) {
  44                 return -EINVAL;
  45         }
  46
  47         newval = uatomic_add_return(&fd_count, (long) nr);
  48         if ((long) (newval * 100)
  49                         - (long) (max_nr_fd * fd_threshold[type]) > 0) {
  50                 uatomic_sub(&fd_count, (long) nr);
  51                 return -EPERM;
  52         }
  53         return 0;
  54 }
  55
  56 void lttng_fd_put(enum lttng_fd_type type, unsigned int nr)
  57 {
  58         uatomic_sub(&fd_count, (long) nr);
  59 }
  60
  61 void lttng_fd_init(void)
  62 {
  63         struct rlimit rlim;
  64         int ret;
  65
  66         ret = getrlimit(RLIMIT_NOFILE, &rlim);
  67         if (ret < 0) {
  68                 PERROR("getrlimit");
  69         }
  70         max_nr_fd = rlim.rlim_cur;
  71 }