Make the implementation and documentation agree. Specifically:

 - document that sysctl() and sysctlbyname() return 0 on success

 - if the provided buffer is too small, set errno to ENOMEM and return -1
   instead of returning ENOMEM.

2 files changed, 11 insertions, 6 deletions

diff --git a/lib/libc/gen/sysctl.3 b/lib/libc/gen/sysctl.3
index 30e8e83..02a185c 100644
--- a/lib/libc/gen/sysctl.3
+++ b/lib/libc/gen/sysctl.3
@@ -667,9 +667,10 @@ If the amount of free and cache memory falls below this value, the
 pageout daemon will enter "memory conserving mode" to avoid deadlock.
 .El
 .Sh RETURN VALUES
-If the call to
 .Fn sysctl
-is successful, the number of bytes copied out is returned.
+and
+.Fn sysctlbyname
+return 0 when successful.
 Otherwise \-1 is returned and
 .Va errno
 is set appropriately.
diff --git a/lib/libc/gen/sysctl.c b/lib/libc/gen/sysctl.c
index cb7448a..19709d5 100644
--- a/lib/libc/gen/sysctl.c
+++ b/lib/libc/gen/sysctl.c
@@ -66,16 +66,20 @@ sysctl(name, namelen, oldp, oldlenp, newp, newlen)
 
 	switch (name[1]) {
 	case USER_CS_PATH:
-		if (oldp && *oldlenp < sizeof(_PATH_STDPATH))
-			return (ENOMEM);
+		if (oldp && *oldlenp < sizeof(_PATH_STDPATH)) {
+			errno = ENOMEM;
+			return -1;
+		}
 		*oldlenp = sizeof(_PATH_STDPATH);
 		if (oldp != NULL)
 			memmove(oldp, _PATH_STDPATH, sizeof(_PATH_STDPATH));
 		return (0);
 	}
 
-	if (oldp && *oldlenp < sizeof(int))
-		return (ENOMEM);
+	if (oldp && *oldlenp < sizeof(int)) {
+		errno = ENOMEM;
+		return (-1);
+	}
 	*oldlenp = sizeof(int);
 	if (oldp == NULL)
 		return (0);