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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.
This commit is contained in:
Adhemerval Zanella
@ -15,70 +15,25 @@
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <signal.h>
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#include <string.h>
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#include <sysdep.h>
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#include <sys/syscall.h>
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/* The difference here is that the sigaction structure used in the
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kernel is not the same as we use in the libc. Therefore we must
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translate it here. */
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#include <kernel_sigaction.h>
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#define SA_RESTORER 0x04000000
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extern void __default_sa_restorer (void);
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extern void __default_rt_sa_restorer (void);
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/* When RT signals are in use we need to use a different return stub. */
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#define choose_restorer(flags) \
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(flags & SA_SIGINFO) ? __default_rt_sa_restorer \
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: __default_sa_restorer
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#define SET_SA_RESTORER(kact, act) \
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({ \
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if ((kact)->sa_flags & SA_RESTORER) \
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(kact)->sa_restorer = (act)->sa_restorer; \
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else \
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{ \
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(kact)->sa_restorer = ((kact)->sa_flags & SA_SIGINFO) \
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? __default_rt_sa_restorer \
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: __default_sa_restorer; \
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(kact)->sa_flags |= SA_RESTORER; \
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} \
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})
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/* If ACT is not NULL, change the action for SIG to *ACT.
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If OACT is not NULL, put the old action for SIG in *OACT. */
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int
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__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
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{
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int result;
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#define RESET_SA_RESTORER(act, kact) \
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(act)->sa_restorer = (kact)->sa_restorer;
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struct kernel_sigaction kact, koact;
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if (act)
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{
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kact.k_sa_handler = act->sa_handler;
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memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
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kact.sa_flags = act->sa_flags;
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#ifdef HAVE_SA_RESTORER
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if (kact.sa_flags & SA_RESTORER)
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kact.sa_restorer = act->sa_restorer;
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else
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{
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kact.sa_restorer = choose_restorer (kact.sa_flags);
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kact.sa_flags |= SA_RESTORER;
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}
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#endif
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}
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/* XXX The size argument hopefully will have to be changed to the
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real size of the user-level sigset_t. */
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result = INLINE_SYSCALL (rt_sigaction, 4, sig,
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act ? &kact : NULL,
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oact ? &koact : NULL, _NSIG / 8);
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if (oact && result >= 0)
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{
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oact->sa_handler = koact.k_sa_handler;
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memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
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oact->sa_flags = koact.sa_flags;
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#ifdef HAVE_SA_RESTORER
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oact->sa_restorer = koact.sa_restorer;
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#endif
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}
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return result;
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}
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libc_hidden_def (__libc_sigaction)
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#include <nptl/sigaction.c>
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#include <sysdeps/unix/sysv/linux/sigaction.c>
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