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
22/* Another sysdeps file can #define this and then #include this file. */
23#ifndef RESERVED_SIGRT
24# define RESERVED_SIGRT 0
25#endif
26
27/* In these variables we keep track of the used variables. If the
28 platform does not support any real-time signals we will define the
29 values to some unreasonable value which will signal failing of all
30 the functions below. */
31#ifdef __SIGRTMIN
32static int current_rtmin = __SIGRTMIN + RESERVED_SIGRT;
33static int current_rtmax = __SIGRTMAX;
34#endif
35
36/* Return number of available real-time signal with highest priority. */
37int
38__libc_current_sigrtmin (void)
39{
40#ifdef __SIGRTMIN
41 return current_rtmin;
42#else
43 return -1;
44#endif
45}
46libc_hidden_def (__libc_current_sigrtmin)
47strong_alias (__libc_current_sigrtmin, __libc_current_sigrtmin_private)
48
49/* Return number of available real-time signal with lowest priority. */
50int
51__libc_current_sigrtmax (void)
52{
53#ifdef __SIGRTMIN
54 return current_rtmax;
55#else
56 return -1;
57#endif
58}
59libc_hidden_def (__libc_current_sigrtmax)
60strong_alias (__libc_current_sigrtmax, __libc_current_sigrtmax_private)
61
62/* Allocate real-time signal with highest/lowest available
63 priority. Please note that we don't use a lock since we assume
64 this function to be called at program start. */
65int
66__libc_allocate_rtsig (int high)
67{
68#ifndef __SIGRTMIN
69 return -1;
70#else
71 if (current_rtmin == -1 || current_rtmin > current_rtmax)
72 /* We don't have any more signals available. */
73 return -1;
74
75 return high ? current_rtmin++ : current_rtmax--;
76#endif
77}
78strong_alias (__libc_allocate_rtsig, __libc_allocate_rtsig_private)
79