lseek, lseek64: add cancellation for all THREADS

LT_OLD provides cancellable versions, do it for all THREADS.
llseek.c: use newly added macros for offset handling.
Add a comment about endianness issue around offset.
Compile llseek.c only on 32bit archs.
Provide aliases for 64bit archs or if syscall is not available.

Signed-off-by: Peter S. Mazinger <ps.m@gmx.net>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

1 files changed, 11 insertions, 17 deletions

diff --git a/libc/sysdeps/linux/common/llseek.c b/libc/sysdeps/linux/common/llseek.c
index 333770af0..09f5435a4 100644
--- a/libc/sysdeps/linux/common/llseek.c
+++ b/libc/sysdeps/linux/common/llseek.c
@@ -9,30 +9,24 @@
 
 #include <_lfs_64.h>
 #include <sys/syscall.h>
-#include <unistd.h>
-#include <stdint.h>
+#include <bits/wordsize.h>
 
 /* Newer kernel ports have llseek() instead of _llseek() */
 #if !defined __NR__llseek && defined __NR_llseek
 # define __NR__llseek __NR_llseek
 #endif
 
-#ifdef __NR__llseek
-off64_t lseek64(int fd, off64_t offset, int whence)
+#if defined __NR__llseek && __WORDSIZE == 32
+# include <unistd.h>
+# include <endian.h>
+# include <cancel.h>
+off64_t __NC(lseek64)(int fd, off64_t offset, int whence)
 {
 	off64_t result;
-	return (off64_t)INLINE_SYSCALL(_llseek, 5, fd, (off_t) (offset >> 32),
-				(off_t) (offset & 0xffffffff), &result, whence) ?: result;
+	/* do we not need to handle the offset with __LONG_LONG_PAIR depending on endianness? */
+	return (off64_t)INLINE_SYSCALL(_llseek, 5, fd, (off_t) OFF64_HI(offset),
+				       (off_t) OFF64_LO(offset), &result, whence) ?: result;
 }
-#else
-off64_t lseek64(int fd, off64_t offset, int whence)
-{
-	return (off64_t)lseek(fd, (off_t) (offset), whence);
-}
-#endif
-#ifndef __LINUXTHREADS_OLD__
-libc_hidden_def(lseek64)
-#else
-libc_hidden_weak(lseek64)
-strong_alias(lseek64,__libc_lseek64)
+CANCELLABLE_SYSCALL(off64_t, lseek64, (int fd, off64_t offset, int whence), (fd, offset, whence))
+lt_libc_hidden(lseek64)
 #endif