1 /* Copyright (C) 1992-2022 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library 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 GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 #include <errno.h> 19 #include <hurd.h> 20 #include <hurd/signal.h> 21 22 /* Run signals handlers on the stack specified by SS (if not NULL). 23 If OSS is not NULL, it is filled in with the old signal stack status. */ 24 int __sigaltstack(const stack_t * argss,stack_t * oss)25__sigaltstack (const stack_t *argss, stack_t *oss) 26 { 27 struct hurd_sigstate *s; 28 stack_t ss, old; 29 30 /* Fault before taking any locks. */ 31 if (argss != NULL) 32 ss = *argss; 33 if (oss != NULL) 34 *(volatile stack_t *) oss = *oss; 35 36 s = _hurd_self_sigstate (); 37 __spin_lock (&s->lock); 38 39 if (argss != NULL 40 && (ss.ss_flags & SS_DISABLE) 41 && (s->sigaltstack.ss_flags & SS_ONSTACK)) 42 { 43 /* Can't disable a stack that is in use. */ 44 __spin_unlock (&s->lock); 45 errno = EINVAL; 46 return -1; 47 } 48 49 old = s->sigaltstack; 50 51 if (argss != NULL) 52 s->sigaltstack = ss; 53 54 __spin_unlock (&s->lock); 55 56 if (oss != NULL) 57 *oss = old; 58 59 return 0; 60 } 61 libc_hidden_def (__sigaltstack) 62 weak_alias (__sigaltstack, sigaltstack) 63