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authorZack Weinberg <zackw@panix.com>2017-06-03 16:22:24 -0400
committerZack Weinberg <zackw@panix.com>2017-06-20 20:32:50 -0400
commit8082d91e1c449e0cb137468b731004a5e605c8c6 (patch)
tree0d90492e10b87d6d30a0c094fae8d7375439938a /signal
parentaf85385f311c574590381f7897461643f8a2fe6f (diff)
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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.
Diffstat (limited to 'signal')
-rw-r--r--signal/Makefile3
-rw-r--r--signal/signal.h3
2 files changed, 5 insertions, 1 deletions
diff --git a/signal/Makefile b/signal/Makefile
index 9ce8232d43..8c9a7d1844 100644
--- a/signal/Makefile
+++ b/signal/Makefile
@@ -23,7 +23,8 @@ subdir	:= signal
 include ../Makeconfig
 
 headers := signal.h sys/signal.h \
-	   bits/signum.h bits/sigcontext.h bits/sigaction.h \
+	   bits/signum.h bits/signum-generic.h \
+	   bits/sigcontext.h bits/sigaction.h \
 	   bits/sigevent-consts.h bits/siginfo-consts.h \
 	   bits/sigstack.h bits/sigthread.h bits/ss_flags.h \
 	   bits/types/__sigset_t.h bits/types/sig_atomic_t.h \
diff --git a/signal/signal.h b/signal/signal.h
index ddb79c7d98..c8f6100ac4 100644
--- a/signal/signal.h
+++ b/signal/signal.h
@@ -363,6 +363,9 @@ extern int __libc_current_sigrtmin (void) __THROW;
 /* Return number of available real-time signal with lowest priority.  */
 extern int __libc_current_sigrtmax (void) __THROW;
 
+#define SIGRTMIN        (__libc_current_sigrtmin ())
+#define SIGRTMAX        (__libc_current_sigrtmax ())
+
 __END_DECLS
 
 #endif /* not signal.h */