glibc/support/xsignal.h
Zack Weinberg fbbc9a4e34 Tests for minimal signal handler functionality in MINSIGSTKSZ space.
There is general agreement that the very short list of things that ISO
C says you can do in an async signal handler should all work when the
handler is running on an alternate signal stack with only MINSIGSTKSZ
space.  This patch adds tests to make sure those things do work.

To facilitate this, there is a new set of test support routines for
setting up alternate signal stacks; see support/xsignal.h for the API.

         * support/xsignal.h (xalloc_sigstack, xfree_sigstack)
         (xget_sigstack_location): New test support functions.
         * support/xsigstack.c: New file, implementing them.
         * support/tst-xsigstack.c: New test for them.
         * support/Makefile: Update.

         * signal/tst-minsigstksz-1.c
         * signal/tst-minsigstksz-2.c
         * signal/tst-minsigstksz-3.c
         * signal/tst-minsigstksz-3a.c
         * signal/tst-minsigstksz-4.c: New tests.
         * signal/Makefile: Run them.
2019-01-16 09:04:10 -05:00

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C

/* Support functionality for using signals.
Copyright (C) 2016-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef SUPPORT_SIGNAL_H
#define SUPPORT_SIGNAL_H
#include <signal.h>
#include <sys/cdefs.h>
__BEGIN_DECLS
/* The following functions call the corresponding libc functions and
terminate the process on error. */
void xraise (int sig);
sighandler_t xsignal (int sig, sighandler_t handler);
void xsigaction (int sig, const struct sigaction *newact,
struct sigaction *oldact);
/* The following functions call the corresponding libpthread functions
and terminate the process on error. */
void xpthread_sigmask (int how, const sigset_t *set, sigset_t *oldset);
/* Allocate and activate an alternate signal stack. This stack will
have SIZE + MINSIGSTKSZ bytes of space, rounded up to a whole
number of pages. There will be large (at least 1 MiB) inaccessible
guard bands on either side of it. The return value is a cookie
that can be passed to xfree_sigstack to deactivate and deallocate
the stack again. It is not necessary to call sigaltstack after
calling this function. Terminates the process on error. */
void *xalloc_sigstack (size_t size);
/* Deactivate and deallocate a signal stack created by xalloc_sigstack. */
void xfree_sigstack (void *stack);
/* Extract the actual address and size of the alternate signal stack from
the cookie returned by xalloc_sigstack. */
void xget_sigstack_location (const void *stack, unsigned char **addrp,
size_t *sizep);
__END_DECLS
#endif /* SUPPORT_SIGNAL_H */