Factor out shared definitions from bits/signum.h.

Many of the things defined by bits/signum.h are invariant across all
supported operating systems.  This patch factors out all of them to a
new header bits/signum-generic.h, which each bits/signum.h will include
and then override whichever things need adjustment.  Normally that will
mean, at most, adding or changing a few signal numbers.

A user-visible side effect is that the obsolete signal constant SIGUNUSED
(which is an alias for SIGSYS on all platforms that define it) is no
longer exposed by any version of bits/signum.h.

A side effect only relevant to glibc hackers is that _NSIG is now defined
in terms of __SIGRTMAX, instead of the other way around.  This is because
__SIGRTMAX varies from platform to platform, but _NSIG==__SIGRTMAX+1 is
true universally.  If your platform doesn't support realtime signals,
leave __SIGRTMAX equal to __SIGRTMIN.

I also added a Linux-specific test to make sure that our signal constants
match the ones in <asm/signal.h>, since we can't use that header (it's
not even vaguely namespace-clean).

	* bits/signum-generic.h: Renamed from bits/signum.h.
	Add proper multiple include guard and misuse check.
	Define __SIGRTMIN = __SIGRTMAX = 32, and define _NSIG = __SIGRTMAX+1.
	Move definition of SIGIO to "archaic names for compatibility" section.
	* bits/signum.h: New file which just includes bits/signum-generic.h.
	* sysdeps/unix/bsd/bits/signum.h
	* sysdeps/unix/sysv/linux/bits/signum.h
	* sysdeps/unix/sysv/linux/alpha/bits/signum.h
	* sysdeps/unix/sysv/linux/hppa/bits/signum.h
	* sysdeps/unix/sysv/linux/mips/bits/signum.h
	* sysdeps/unix/sysv/linux/sparc/bits/signum.h
	Just include <bits/signum-generic.h> and then add or adjust
	signal constants.  Do not define SIGUNUSED, SIGRTMIN, or SIGRTMAX.

	* signal/Makefile: Install bits/signum-generic.h.
	* signal/signal.h: Define SIGRTMIN and SIGRTMAX here.

	* sysdeps/generic/siglist.h: SIGSYS and SIGWINCH are
	universal.  Prefer SIGPOLL to SIGIO. Simplify #ifdeffage.

	* sysdeps/unix/sysv/linux/tst-signal-numbers.sh: New test.
	* sysdeps/unix/sysv/linux/Makefile: Run it.

1 files changed, 35 insertions, 56 deletions

diff --git a/sysdeps/unix/sysv/linux/bits/signum.h b/sysdeps/unix/sysv/linux/bits/signum.h
index e30efead0d..1a68255d02 100644
--- a/sysdeps/unix/sysv/linux/bits/signum.h
+++ b/sysdeps/unix/sysv/linux/bits/signum.h
@@ -16,64 +16,43 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#ifdef	_SIGNAL_H
+#ifndef _BITS_SIGNUM_H
+#define _BITS_SIGNUM_H 1
 
-/* Fake signal functions.  */
-#define SIG_ERR	((__sighandler_t) -1)		/* Error return.  */
-#define SIG_DFL	((__sighandler_t) 0)		/* Default action.  */
-#define SIG_IGN	((__sighandler_t) 1)		/* Ignore signal.  */
-
-#ifdef __USE_XOPEN
-# define SIG_HOLD	((__sighandler_t) 2)	/* Add signal to hold mask.  */
+#ifndef _SIGNAL_H
+#error "Never include <bits/signum.h> directly; use <signal.h> instead."
 #endif
 
-
-/* Signals.  */
-#define	SIGHUP		1	/* Hangup (POSIX).  */
-#define	SIGINT		2	/* Interrupt (ANSI).  */
-#define	SIGQUIT		3	/* Quit (POSIX).  */
-#define	SIGILL		4	/* Illegal instruction (ANSI).  */
-#define	SIGTRAP		5	/* Trace trap (POSIX).  */
-#define	SIGABRT		6	/* Abort (ANSI).  */
-#define	SIGIOT		6	/* IOT trap (4.2 BSD).  */
-#define	SIGBUS		7	/* BUS error (4.2 BSD).  */
-#define	SIGFPE		8	/* Floating-point exception (ANSI).  */
-#define	SIGKILL		9	/* Kill, unblockable (POSIX).  */
-#define	SIGUSR1		10	/* User-defined signal 1 (POSIX).  */
-#define	SIGSEGV		11	/* Segmentation violation (ANSI).  */
-#define	SIGUSR2		12	/* User-defined signal 2 (POSIX).  */
-#define	SIGPIPE		13	/* Broken pipe (POSIX).  */
-#define	SIGALRM		14	/* Alarm clock (POSIX).  */
-#define	SIGTERM		15	/* Termination (ANSI).  */
-#define	SIGSTKFLT	16	/* Stack fault.  */
-#define	SIGCLD		SIGCHLD	/* Same as SIGCHLD (System V).  */
-#define	SIGCHLD		17	/* Child status has changed (POSIX).  */
-#define	SIGCONT		18	/* Continue (POSIX).  */
-#define	SIGSTOP		19	/* Stop, unblockable (POSIX).  */
-#define	SIGTSTP		20	/* Keyboard stop (POSIX).  */
-#define	SIGTTIN		21	/* Background read from tty (POSIX).  */
-#define	SIGTTOU		22	/* Background write to tty (POSIX).  */
-#define	SIGURG		23	/* Urgent condition on socket (4.2 BSD).  */
-#define	SIGXCPU		24	/* CPU limit exceeded (4.2 BSD).  */
-#define	SIGXFSZ		25	/* File size limit exceeded (4.2 BSD).  */
-#define	SIGVTALRM	26	/* Virtual alarm clock (4.2 BSD).  */
-#define	SIGPROF		27	/* Profiling alarm clock (4.2 BSD).  */
-#define	SIGWINCH	28	/* Window size change (4.3 BSD, Sun).  */
-#define	SIGPOLL		SIGIO	/* Pollable event occurred (System V).  */
-#define	SIGIO		29	/* I/O now possible (4.2 BSD).  */
-#define	SIGPWR		30	/* Power failure restart (System V).  */
-#define SIGSYS		31	/* Bad system call.  */
-#define SIGUNUSED	31
-
-#define	_NSIG		65	/* Biggest signal number + 1
-				   (including real-time signals).  */
-
-#define SIGRTMIN        (__libc_current_sigrtmin ())
-#define SIGRTMAX        (__libc_current_sigrtmax ())
-
-/* These are the hard limits of the kernel.  These values should not be
-   used directly at user level.  */
-#define __SIGRTMIN	32
-#define __SIGRTMAX	(_NSIG - 1)
+#include <bits/signum-generic.h>
+
+/* Adjustments and additions to the signal number constants for
+   most Linux systems.  */
+
+#define	SIGSTKFLT	16	/* Stack fault (obsolete).  */
+#define	SIGPWR		30	/* Power failure imminent.  */
+
+#undef	SIGBUS
+#define	SIGBUS		 7
+#undef	SIGUSR1
+#define	SIGUSR1		10
+#undef	SIGUSR2
+#define	SIGUSR2		12
+#undef	SIGCHLD
+#define	SIGCHLD		17
+#undef	SIGCONT
+#define	SIGCONT		18
+#undef	SIGSTOP
+#define	SIGSTOP		19
+#undef	SIGTSTP
+#define	SIGTSTP		20
+#undef	SIGURG
+#define	SIGURG		23
+#undef	SIGPOLL
+#define	SIGPOLL		29
+#undef	SIGSYS
+#define SIGSYS		31
+
+#undef	__SIGRTMAX
+#define __SIGRTMAX	64
 
 #endif	/* <signal.h> included.  */