signal: Add __libc_sigaction

The generic implementation basically handle the system agnostic logic
(filtering out the invalid signals) while the __libc_sigaction is
the function with implements the system and architecture bits.

Checked on x86_64-linux-gnu and i686-linux-gnu.

nptl/Makefile

@@ -225,6 +225,7 @@ libpthread-routines = \
   sem_unlink \
   sem_wait \
   sigaction \
+  libc_sigaction \
   tpp \
   unwind \
   unwind-forcedunwind \

signal/Makefile

@@ -35,7 +35,7 @@ headers := signal.h sys/signal.h \
 	   bits/sigstksz.h
 
 routines	:= signal raise killpg \
-		   sigaction sigprocmask kill \
+		   sigaction libc_sigaction sigprocmask kill \
 		   sigpending sigsuspend sigwait \
 		   sigblock sigsetmask sigpause sigvec \
 		   sigstack sigaltstack sigintr \

signal/libc_sigaction.c

@@ -0,0 +1,32 @@
+/* Internal sigaction definitions.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <signal.h>
+
+/* 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)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+stub_warning (libc_sigaction)
+libc_hidden_def (__libc_sigaction)

signal/sigaction.c

@@ -17,7 +17,7 @@
 
 #include <errno.h>
 #include <signal.h>
-
+#include <internal-signals.h>
 
 /* 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.  */
@@ -30,10 +30,7 @@ __sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
       return -1;
     }
 
-  __set_errno (ENOSYS);
-  return -1;
+  return __libc_sigaction (sig, act, oact);
 }
 libc_hidden_def (__sigaction)
-stub_warning (sigaction)
-
 weak_alias (__sigaction, sigaction)

sysdeps/mach/hurd/libc_sigaction.c

@@ -24,16 +24,15 @@
 /* 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
-__sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
+__libc_sigaction (int sig, const struct sigaction *act,
+		  struct sigaction *oact)
 {
   struct hurd_sigstate *ss;
   struct sigaction a, old;
   sigset_t pending;
 
-  if (sig <= 0 || sig >= NSIG
-      || (act != NULL && act->sa_handler != SIG_DFL
-	  && ((__sigmask (sig) & _SIG_CANT_MASK)
-	      || act->sa_handler == SIG_ERR)))
+  if (act != NULL && act->sa_handler != SIG_DFL
+      && ((__sigmask (sig) & _SIG_CANT_MASK) || act->sa_handler == SIG_ERR))
     {
       errno = EINVAL;
       return -1;
@@ -87,5 +86,4 @@ __sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
 
   return 0;
 }
-libc_hidden_def (__sigaction)
-weak_alias (__sigaction, sigaction)
+libc_hidden_def (__libc_sigaction)

sysdeps/unix/syscalls.list

@@ -74,7 +74,6 @@ setsid		-	setsid		i:	__setsid	setsid
 setsockopt	-	setsockopt	i:iiibn	setsockopt	__setsockopt
 setuid		-	setuid		i:i	__setuid	setuid
 shutdown	-	shutdown	i:ii	shutdown
-sigaction	-	sigaction	i:ipp	__sigaction	sigaction
 sigsuspend	-	sigsuspend	Ci:p	sigsuspend
 socket		-	socket		i:iii	__socket	socket
 socketpair	-	socketpair	i:iiif	socketpair

sysdeps/unix/sysv/linux/aarch64/libc_sigaction.c

@@ -27,4 +27,4 @@
 #define RESET_SA_RESTORER(act, kact)		\
   (act)->sa_restorer = (kact)->sa_restorer;
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>

sysdeps/unix/sysv/linux/arc/libc_sigaction.c

@@ -28,4 +28,4 @@ extern void __default_rt_sa_restorer (void);
 
 #define RESET_SA_RESTORER(act, kact)
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>

sysdeps/unix/sysv/linux/arm/libc_sigaction.c

@@ -36,4 +36,4 @@ extern void __default_rt_sa_restorer (void);
 #define RESET_SA_RESTORER(act, kact)				\
   (act)->sa_restorer = (kact)->sa_restorer;
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>

sysdeps/unix/sysv/linux/i386/libc_sigaction.c

@@ -39,7 +39,7 @@ extern void restore (void) asm ("__restore") attribute_hidden;
 #define RESET_SA_RESTORER(act, kact) \
   (act)->sa_restorer = (kact)->sa_restorer
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>
 
 /* NOTE: Please think twice before making any changes to the bits of
    code below.  GDB needs some intimate knowledge about it to

sysdeps/unix/sysv/linux/libc_sigaction.c

@@ -70,5 +70,3 @@ __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
   return result;
 }
 libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>

sysdeps/unix/sysv/linux/sparc/sparc32/libc_sigaction.c

@@ -34,4 +34,4 @@ void __sigreturn_stub (void);
 	: 0,						\
   (sigsetsize)
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>

sysdeps/unix/sysv/linux/sparc/sparc64/libc_sigaction.c

@@ -29,4 +29,4 @@ void __rt_sigreturn_stub (void);
   (((unsigned long) &__rt_sigreturn_stub) - 8),	\
   (sigsetsize)
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>

sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c

@@ -30,7 +30,7 @@ extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;
 
 #include <kernel_sigaction.h>
 
-#include <sysdeps/unix/sysv/linux/sigaction.c>
+#include <sysdeps/unix/sysv/linux/libc_sigaction.c>
 
 /* NOTE: Please think twice before making any changes to the bits of
    code below.  GDB needs some intimate knowledge about it to