klibc: Default signal(3) to bsd_signal(3)
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>
diff --git a/usr/include/signal.h b/usr/include/signal.h
index bb6b470..a513282 100644
--- a/usr/include/signal.h
+++ b/usr/include/signal.h
@@ -88,6 +88,9 @@
}
__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 02b9b9e..2cead70 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 @@
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 @@
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 @@
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 4e6238c..3d78d2c 100644
--- a/usr/klibc/bsd_signal.c
+++ b/usr/klibc/bsd_signal.c
@@ -9,3 +9,6 @@
/* BSD signal() semantics */
return __signal(signum, handler, SA_RESTART);
}
+
+__sighandler_t signal(int signum, __sighandler_t handler)
+ __alias("bsd_signal");
