glibc/sysdeps/unix/sysv/linux/sigaction.c
Adhemerval Zanella b4a5d26d88 linux: Consolidate sigaction implementation
This patch consolidates all Linux sigaction implementations on the default
sysdeps/unix/sysv/linux/sigaction.c.  The idea is remove redundant code
and simplify new ports addition by following the current generic
Linux User API (UAPI).

The UAPI for new ports defines a generic extensible sigaction struct as:

  struct sigaction
  {
    __sighandler_t sa_handler;
    unsigned long sa_flags;
  #ifdef SA_RESTORER
    void (*sa_restorer) (void);
  #endif
    sigset_t sa_mask;
  };

Where SA_RESTORER is just placed for compatibility reasons (news ports
should not add it).  A similar definition is used on generic
kernel_sigaction.h.

The user exported sigaction definition is not changed, so for most
architectures it requires an adjustment to kernel expected one for the
syscall.

The main changes are:

  - All architectures now define and use a kernel_sigaction struct meant
    for the syscall, even for the architectures where the user sigaction
    has the same layout of the kernel expected one (s390-64 and ia64).
    Although it requires more work for these architectures, it simplifies
    the generic implementation. Also, sigaction is hardly a hotspot where
    micro optimization would play an important role.

  - The generic kernel_sigaction definition is now aligned with expected
    UAPI one for newer ports, where SA_RESTORER and sa_restorer are not
    expected to be defined.  This means adding kernel_sigaction for
    current architectures that does define it (m68k, nios2, powerpc, s390,
    sh, sparc, and tile) and which rely on previous generic definition.

  - Remove old MIPS usage of sa_restorer.  This was removed since 2.6.27
    (2957c9e61ee9c - "[MIPS] IRIX: Goodbye and thanks for all the fish").

  - The remaining arch-specific sigaction.c are to handle ABI idiosyncrasies
    (like SPARC kernel ABI for rt_sigaction that requires an additional
    stub argument).

So for new ports the generic implementation should work if its uses
Linux UAPI.  If SA_RESTORER is still required (due some architecture
limitation), it should define its own kernel_sigaction.h, define it and
include generic header (assuming it still uses the default generic kernel
layout).

Checked on x86_64-linux-gnu, i686-linux-gnu, arm-linux-gnueabihf,
aarch64-linux-gnu, sparc64-linux-gnu, sparcv9-linux-gnu, powerpc-linux-gnu,
powerpc64-linux-gnu, ia64-linux-gnu and alpha-linux-gnu.  I also checked the
build on all remaining affected ABIs.

	* sysdeps/unix/sysv/linux/aarch64/sigaction.c: Use default Linux version
	as base implementation.
	* sysdeps/unix/sysv/linux/arm/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h: Add include guards,
	remove unrequired definitions and update comments.
	* sysdeps/unix/sysv/linux/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/ia64/kernel_sigaction.h: New file.
	* sysdeps/unix/sysv/linux/m68k/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/nios2/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/kernel_sigaction: Likewise.
	* sysdeps/unix/sysv/linux/s390/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/sh/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/sparc/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/tile/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/ia64/sigaction.c: Remove file.
	* sysdeps/unix/sysv/linux/mips/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/sigaction.c: Add STUB, SET_SA_RESTORER,
	and RESET_SA_RESTORER hooks.
2018-04-05 17:09:50 -03:00

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2.2 KiB
C

/* Copyright (C) 1997-2018 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/>. */
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sysdep.h>
#include <sys/syscall.h>
/* New ports should not define the obsolete SA_RESTORER, however some
architecture requires for compat mode and/or due old ABI. */
#include <kernel_sigaction.h>
#ifndef SA_RESTORER
# define SET_SA_RESTORER(kact, act)
# define RESET_SA_RESTORER(act, kact)
#endif
/* SPARC passes the restore function as an argument to rt_sigaction. */
#ifndef STUB
# define STUB(act)
#endif
/* If ACT is not NULL, change the action for SIG to *ACT.
If OACT is not NULL, put the old action for SIG in *OACT. */
int
__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
{
int result;
struct kernel_sigaction kact, koact;
if (act)
{
kact.k_sa_handler = act->sa_handler;
memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
kact.sa_flags = act->sa_flags;
SET_SA_RESTORER (&kact, act);
}
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
result = INLINE_SYSCALL_CALL (rt_sigaction, sig,
act ? &kact : NULL,
oact ? &koact : NULL, STUB(act) _NSIG / 8);
if (oact && result >= 0)
{
oact->sa_handler = koact.k_sa_handler;
memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
oact->sa_flags = koact.sa_flags;
RESET_SA_RESTORER (oact, &koact);
}
return result;
}
libc_hidden_def (__libc_sigaction)
#include <nptl/sigaction.c>