From: Sascha Wildner <saw@online.de>
Date: Sun, 25 Oct 2015 21:47:18 +0000 (+0100)
Subject: libc/sysconf: Simplify sysconf(_SC_XOPEN_SHM) a bit.
X-Git-Tag: v4.5.0~294
X-Git-Url: https://gitweb.dragonflybsd.org/~tuxillo/dragonfly.git/commitdiff_plain/2f6482abea88bce07df7c4a5491a44a06ed5e3c7

libc/sysconf: Simplify sysconf(_SC_XOPEN_SHM) a bit.

We never had sysv_shm as a module like FreeBSD, only as a kernel
option (SYSVSHM), which was made a no-op when we started to compile
it into our kernels by default over a year ago (see 10ceb70237a5).

The sysctl check in the sysconf(3) code was only there to check if
it was compiled into the kernel or (in FreeBSD's case) if it was
loaded as a module, when it was still optional.

So the worst thing that could happen after this commit is a wrong
return value for sysconf(_SC_XOPEN_SHM) if someone was running a
kernel without "options SYSVSHM" from earlier than July 29, 2014
in combination with a current world. This all looks quite unlikely,
so remove the check.

Also, return the right variable from <unistd.h>.
---

diff --git a/lib/libc/gen/sysconf.c b/lib/libc/gen/sysconf.c
index 91126460a3..230cdaf74b 100644
--- a/lib/libc/gen/sysconf.c
+++ b/lib/libc/gen/sysconf.c
@@ -588,15 +588,7 @@ yesno:
 		return (_XOPEN_REALTIME_THREADS);
 #endif
 	case _SC_XOPEN_SHM:
-		len = sizeof(lvalue);
-		sverrno = errno;
-		if (sysctlbyname("kern.ipc.shmmin", &lvalue, &len, NULL,
-		    0) == -1) {
-			errno = sverrno;
-			return (-1);
-		}
-		errno = sverrno;
-		return (1);
+		return (_XOPEN_SHM);
 	case _SC_XOPEN_STREAMS:
 		return (_XOPEN_STREAMS);
 	case _SC_XOPEN_UNIX: