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, 10 insertions, 48 deletions

diff --git a/sysdeps/unix/bsd/bits/signum.h b/sysdeps/unix/bsd/bits/signum.h
index 268c24a..f55edc9 100644
--- a/sysdeps/unix/bsd/bits/signum.h
+++ b/sysdeps/unix/bsd/bits/signum.h
@@ -16,58 +16,20 @@
    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
 
-/* This file defines the fake signal functions and signal
-   number constants for 4.2 or 4.3 BSD-derived Unix system.  */
-
-/* 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
 
+#include <bits/signum-generic.h>
 
-/* Signals.  */
-#define	SIGHUP		1	/* Hangup (POSIX).  */
-#define	SIGINT		2	/* Interrupt (ANSI).  */
-#define	SIGQUIT		3	/* Quit (POSIX).  */
-#define	SIGILL		4	/* Illegal instruction (ANSI).  */
-#define	SIGABRT		SIGIOT	/* Abort (ANSI).  */
-#define	SIGTRAP		5	/* Trace trap (POSIX).  */
-#define	SIGIOT		6	/* IOT trap (4.2 BSD).  */
-#define	SIGEMT		7	/* EMT trap (4.2 BSD).  */
-#define	SIGFPE		8	/* Floating-point exception (ANSI).  */
-#define	SIGKILL		9	/* Kill, unblockable (POSIX).  */
-#define	SIGBUS		10	/* Bus error (4.2 BSD).  */
-#define	SIGSEGV		11	/* Segmentation violation (ANSI).  */
-#define	SIGSYS		12	/* Bad argument to system call (4.2 BSD).  */
-#define	SIGPIPE		13	/* Broken pipe (POSIX).  */
-#define	SIGALRM		14	/* Alarm clock (POSIX).  */
-#define	SIGTERM		15	/* Termination (ANSI).  */
-#define	SIGURG		16	/* Urgent condition on socket (4.2 BSD).  */
-#define	SIGSTOP		17	/* Stop, unblockable (POSIX).  */
-#define	SIGTSTP		18	/* Keyboard stop (POSIX).  */
-#define	SIGCONT		19	/* Continue (POSIX).  */
-#define	SIGCHLD		20	/* Child status has changed (POSIX).  */
-#define	SIGCLD		SIGCHLD	/* Same as SIGCHLD (System V).  */
-#define	SIGTTIN		21	/* Background read from tty (POSIX).  */
-#define	SIGTTOU		22	/* Background write to tty (POSIX).  */
-#define	SIGIO		23	/* I/O now possible (4.2 BSD).  */
-#define	SIGPOLL		SIGIO	/* Same as SIGIO? (SVID).  */
-#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).  */
+/* Adjustments and additions to the signal number constants for
+   4.2 or 4.3 BSD-derived Unix systems.  */
+
+#define SIGEMT		 7	/* Emulator trap (4.2 BSD).  */
 #define SIGINFO		29	/* Information request (4.4 BSD).  */
-#define	SIGUSR1		30	/* User-defined signal 1 (POSIX).  */
-#define	SIGUSR2		31	/* User-defined signal 2 (POSIX).  */
 #define SIGLOST		32	/* Resource lost (Sun); server died (GNU).  */
 
-#endif	/* <signal.h> included.  */
-
-#define	_NSIG		33	/* Biggest signal number + 1.  */
+#endif /* bits/signum.h.  */