Change the C wrappers for mmap/lseek/pread/pwrite/truncate/ftruncate to

call the pad-less versions of the corresponding syscalls if the running
kernel supports it.  Check kern.osreldate once per program and cache the
result to select the appropriate syscall.  This maintains userland
compatability with kernel.old's from quite a while back.

Approved by:  re (kensmith)

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/libc/sys/pwrite.c b/lib/libc/sys/pwrite.c
index ebbb1ec..d17ed29 100644
--- a/lib/libc/sys/pwrite.c
+++ b/lib/libc/sys/pwrite.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 #include <sys/syscall.h>
 #include <unistd.h>
+#include "libc_private.h"
 
 /*
  * This function provides 64-bit offset padding that
@@ -48,5 +49,8 @@ pwrite(fd, buf, nbyte, offset)
 	size_t	nbyte;
 	off_t	offset;
 {
-	return ((ssize_t)__syscall((quad_t)SYS_pwrite, fd, buf, nbyte, 0, offset));
+	if (__getosreldate() >= 700051)
+		return (__sys_pwrite(fd, buf, nbyte, offset));
+	else
+		return (__sys_freebsd6_pwrite(fd, buf, nbyte, 0, offset));
 }