linuxthreads/sysdeps/unix/sysv/linux/allocrtsig.c

   1 /* Handle real-time signal allocation.
   2    Copyright (C) 1997,98,99,2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <signal.h>
  22
  23 /* Sanity check.  */
  24 #if !defined __SIGRTMIN || (__SIGRTMAX - __SIGRTMIN) < 3
  25 # error "This must not happen"
  26 #endif
  27
  28 static int current_rtmin;
  29 static int current_rtmax;
  30
  31 static int initialized;
  32
  33 #include <testrtsig.h>
  34
  35 static void
  36 init (void)
  37 {
  38   if (!kernel_has_rtsig ())
  39     {
  40       current_rtmin = -1;
  41       current_rtmax = -1;
  42     }
  43   else
  44     {
  45       current_rtmin = __SIGRTMIN + 3;
  46       current_rtmax = __SIGRTMAX;
  47     }
  48   initialized = 1;
  49 }
  50
  51 /* Return number of available real-time signal with highest priority.  */
  52 int
  53 __libc_current_sigrtmin (void)
  54 {
  55   if (!initialized)
  56     init ();
  57   return current_rtmin;
  58 }
  59 strong_alias (__libc_current_sigrtmin, __libc_current_sigrtmin_private);
  60 libc_hidden_def (__libc_current_sigrtmin)
  61
  62 /* Return number of available real-time signal with lowest priority.  */
  63 int
  64 __libc_current_sigrtmax (void)
  65 {
  66   if (!initialized)
  67     init ();
  68   return current_rtmax;
  69 }
  70 strong_alias (__libc_current_sigrtmax, __libc_current_sigrtmax_private);
  71 libc_hidden_def (__libc_current_sigrtmax)
  72
  73 /* Allocate real-time signal with highest/lowest available
  74    priority.  Please note that we don't use a lock since we assume
  75    this function to be called at program start.  */
  76 int
  77 __libc_allocate_rtsig (int high)
  78 {
  79   if (!initialized)
  80     init ();
  81   if (current_rtmin == -1 || current_rtmin > current_rtmax)
  82     /* We don't have anymore signal available.  */
  83     return -1;
  84
  85   return high ? current_rtmin++ : current_rtmax--;
  86 }
  87 strong_alias (__libc_allocate_rtsig, __libc_allocate_rtsig_private);