lib/ext2fs: llseek: simplify linux section

On 32-bit musl systems, off_t is always 8 bytes regardless of
_FILE_OFFSET_BITS. The previous code did not cover this case.

The previous #ifdef logic was rather confusing, so I reworked it into a
more understandable form.

Bug: https://bugs.gentoo.org/908892
Signed-off-by: Mike Gilbert <floppym@gentoo.org>
Closes: https://github.com/tytso/e2fsprogs/pull/150
Signed-off-by: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/r/20231107233323.2013334-2-sam@gentoo.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/lib/ext2fs/llseek.c b/lib/ext2fs/llseek.c
index 45f21d0..9118b23 100644 (file)
--- a/lib/ext2fs/llseek.c
+++ b/lib/ext2fs/llseek.c
@@ -35,68 +35,32 @@
 
 #ifdef __linux__
 
-#if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE)
-
-#define my_llseek lseek64
-
-#else
-#if defined(HAVE_LLSEEK)
-#include <sys/syscall.h>
-
-#ifndef HAVE_LLSEEK_PROTOTYPE
-extern long long llseek (int fd, long long offset, int origin);
-#endif
-
-#define my_llseek llseek
-
-#else  /* ! HAVE_LLSEEK */
-
-#if SIZEOF_LONG == SIZEOF_LONG_LONG || _FILE_OFFSET_BITS+0 == 64
-
-#define my_llseek lseek
-
-#else /* SIZEOF_LONG != SIZEOF_LONG_LONG */
-
 #include <linux/unistd.h>
 
-#ifndef __NR__llseek
-#define __NR__llseek            140
-#endif
-
-#ifndef __i386__
-static int _llseek (unsigned int, unsigned long,
-                  unsigned long, ext2_loff_t *, unsigned int);
-
-static _syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,
-                unsigned long, offset_low,ext2_loff_t *,result,
-                unsigned int, origin);
-#endif
-
 static ext2_loff_t my_llseek (int fd, ext2_loff_t offset, int origin)
 {
-       ext2_loff_t result;
+#if SIZEOF_OFF_T >= 8
+       return lseek(fd, offset, origin);
+#elif HAVE_LSEEK64_PROTOTYPE
+       return lseek64(fd, offset, origin);
+#elif HAVE_LLSEEK_PROTOTYPE
+       return llseek(fd, offset, origin);
+#elif defined(__NR__llseek)
+       loff_t result;
        int retval;
-
-#ifndef __i386__
-       retval = _llseek(fd, ((unsigned long long) offset) >> 32,
+       retval = syscall(__NR__llseek, fd,
+               (unsigned long)(offset >> 32),
+               (unsigned long)(offset & 0xffffffff),
+               &result, origin);
+       return (retval == -1 ? retval : result);
 #else
-       retval = syscall(__NR__llseek, fd, (unsigned long long) (offset >> 32),
+       errno = ENOSYS;
+       return -1;
 #endif
-                         ((unsigned long long) offset) & 0xffffffff,
-                       &result, origin);
-       return (retval == -1 ? (ext2_loff_t) retval : result);
 }
 
-#endif /* SIZE_LONG == SIZEOF_LONG_LONG */
-
-#endif /* HAVE_LLSEEK */
-#endif /* defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) */
-
 ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)
 {
-#if SIZEOF_OFF_T >= SIZEOF_LONG_LONG
-       return my_llseek (fd, offset, origin);
-#else
        ext2_loff_t result;
        static int do_compat = 0;
 
@@ -117,7 +81,6 @@ ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)
                return -1;
        }
        return result;
-#endif
 }
 
 #else /* !linux */