1/* Handle real-time signal allocation. Generic version.
2 Copyright (C) 1997-2021 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, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <signal.h>
21#include <internal-signals.h>
22
23/* In these variables we keep track of the used variables. If the
24 platform does not support any real-time signals we will define the
25 values to some unreasonable value which will signal failing of all
26 the functions below. */
27#ifdef __SIGRTMIN
28static int current_rtmin = __SIGRTMIN + RESERVED_SIGRT;
29static int current_rtmax = __SIGRTMAX;
30#endif
31
32/* Return number of available real-time signal with highest priority. */
33int
34__libc_current_sigrtmin (void)
35{
36#ifdef __SIGRTMIN
37 return current_rtmin;
38#else
39 return -1;
40#endif
41}
42libc_hidden_def (__libc_current_sigrtmin)
43
44/* Return number of available real-time signal with lowest priority. */
45int
46__libc_current_sigrtmax (void)
47{
48#ifdef __SIGRTMIN
49 return current_rtmax;
50#else
51 return -1;
52#endif
53}
54libc_hidden_def (__libc_current_sigrtmax)
55
56/* Allocate real-time signal with highest/lowest available
57 priority. Please note that we don't use a lock since we assume
58 this function to be called at program start. */
59int
60__libc_allocate_rtsig (int high)
61{
62#ifndef __SIGRTMIN
63 return -1;
64#else
65 if (current_rtmin == -1 || current_rtmin > current_rtmax)
66 /* We don't have any more signals available. */
67 return -1;
68
69 return high ? current_rtmin++ : current_rtmax--;
70#endif
71}
72