klibc: Default signal(3) to bsd_signal(3)klibc-1.5.14

The Linux universe, at least, seems to have settled on BSD semantics
for signal(3) -- even though signal(2) implements SysV semantics.
POSIX has gone from mandating SysV semantics to permitting either.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

3 files changed, 7 insertions, 11 deletions

diff --git a/usr/include/signal.h b/usr/include/signal.h
index bb6b4702e205c..a513282d884be 100644
--- a/usr/include/signal.h
+++ b/usr/include/signal.h
@@ -88,6 +88,9 @@ static __inline__ int sigismember(sigset_t * __set, int __signum)
 }
 
 __extern __sighandler_t __signal(int, __sighandler_t, int);
+#ifndef signal
+__extern __sighandler_t signal(int, __sighandler_t);
+#endif
 __extern __sighandler_t sysv_signal(int, __sighandler_t);
 __extern __sighandler_t bsd_signal(int, __sighandler_t);
 __extern int sigaction(int, const struct sigaction *, struct sigaction *);
diff --git a/usr/klibc/CAVEATS b/usr/klibc/CAVEATS
index 02b9b9e8877f4..2cead701002d1 100644
--- a/usr/klibc/CAVEATS
+++ b/usr/klibc/CAVEATS
@@ -4,7 +4,6 @@
 
 optimization:
 -------------
-
 Compiling with -O0 is not supported.  It may or may not work; please
 use -O1 if you want to do maximize debuggability.
 
@@ -13,7 +12,6 @@ Compiling with -O0 is more likely to work on gcc 3.
 
 setjmp()/longjmp():
 -------------------
-
 setjmp() and longjmp() *do not* save signal state.  sigsetjmp() and
 siglongjmp() *do* save the signal mask -- regardless of the value of
 the extra argument.
@@ -27,7 +25,6 @@ value of 0 you get what you deserve -- setjmp() will happily return 0.
 
 stdio:
 ------
-
 Only a small subset of the stdio functions are implemented.  Those
 that are implemented do not buffer, although they *do* trap EINTR or
 short read/writes and iterate.
@@ -38,23 +35,16 @@ read/write), but do handle EINTR/short return are also available.
 
 namespaces:
 -----------
-
 klibc frequently includes headers in other headers in a way that
 exposes more symbols than POSIX says they should.  "Live with it."
 
 
 theading:
 ---------
-
 klibc is not thread-safe.  Consequently, clone() or any of the
 pthreads functions are not included.
 
 
 bsd_signal vs sysv_signal:
 --------------------------
-
-There is no signal() call, because you never know if you want
-Linux/SysV semantics (SA_RESETHAND) or GNU/BSD semantics (SA_RESTART).
-The best, in *any* circumstances, is to never use signal() and instead
-use sigaction(), but in order to simplify porting you can use either
-sysv_signal() or bsd_signal(), depending on what you actually want.
+signal() now defaults to bsd_signal().
diff --git a/usr/klibc/bsd_signal.c b/usr/klibc/bsd_signal.c
index 4e6238c915688..3d78d2c2b1cbb 100644
--- a/usr/klibc/bsd_signal.c
+++ b/usr/klibc/bsd_signal.c
@@ -9,3 +9,6 @@ __sighandler_t bsd_signal(int signum, __sighandler_t handler)
 	/* BSD signal() semantics */
 	return __signal(signum, handler, SA_RESTART);
 }
+
+__sighandler_t signal(int signum, __sighandler_t handler)
+  __alias("bsd_signal");