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-rw-r--r--libc/sysdeps/linux/common/xstatconv.c72
1 files changed, 69 insertions, 3 deletions
diff --git a/libc/sysdeps/linux/common/xstatconv.c b/libc/sysdeps/linux/common/xstatconv.c
index 60ec25bd5..325b70550 100644
--- a/libc/sysdeps/linux/common/xstatconv.c
+++ b/libc/sysdeps/linux/common/xstatconv.c
@@ -55,26 +55,92 @@ void __xstat_conv(struct kernel_stat *kbuf, struct stat *buf)
#endif
}
- #if defined(__UCLIBC_HAS_LFS__)
+#if defined(__UCLIBC_HAS_LFS__)
+
+/* OK, this is ugly, but not much we can do about it.
+ *
+ * The issue at hand is that the kernel introduced an ABI change between
+ * 2.4 and 2.6 for big endian machines on some architectures in stat64 with
+ * st_dev and st_rdev fields. Older kernels used 'short' but newer kernels
+ * use a 'long'. As if that wasn't fun enough, the location of st_blocks and
+ * its padding have swapped. So, when applicable, we need to detect and shift
+ * bits around and hope for the best. The kernel at least helps us out a bit
+ * because it will be sure to zero out all padding fields.
+ *
+ * Unimportant Note About Mis-detections:
+ * - if user is running a 2.4 system with the old ABI and they stat a file on
+ * a system which major 0 / minor 0. We can ignore this though because the
+ * kernel has major 0 reserved for non mountable devices (wh00t!)
+ * - if user is running a 2.6 system with the new ABI and they stat a file on
+ * a device whose st_dev fills up the lower 6 bytes into the upper 2 bytes
+ * which overlap. Again we should be able to safely ignore this because
+ * that means it'd be a pretty big ass (read: uncommon) major/minor combo :).
+
+ Old [2.4]:
+struct stat64 {
+ unsigned short st_dev;
+ unsigned char __pad0[10];
+ ...
+ unsigned long st_blocks;
+ unsigned long __pad4;
+ ...
+ New [2.6]:
+struct stat64 {
+ unsigned long long st_dev;
+ unsigned char __pad0[4];
+ ...
+ unsigned long __pad4;
+ unsigned long st_blocks;
+ ...
+
+ * sizeof(unsigned short) = 2
+ * sizeof(unsigned long long) = 8
+ */
+#include <endian.h>
+#include <sys/utsname.h>
+#if BYTE_ORDER == BIG_ENDIAN && \
+ (defined(__ARMEB__)) /* || defined(__sh__) || defined(__sparc__))*/
+# define NEED_ABI_CHECK 1
+#else
+# define NEED_ABI_CHECK 0
+#endif
+
void __xstat64_conv(struct kernel_stat64 *kbuf, struct stat64 *buf)
{
/* Convert to current kernel version of `struct stat64'. */
+
+#if NEED_ABI_CHECK
+ if (!kbuf->st_dev.old_abi) {
+ /* new 2.6 ABI */
+ buf->st_dev = kbuf->st_dev.new_abi;
+ buf->st_rdev = kbuf->st_rdev.new_abi;
+ buf->st_blocks = kbuf->st_blocks;
+ } else {
+ /* old 2.4 ABI */
+ buf->st_dev = kbuf->st_dev.old_abi;
+ buf->st_rdev = kbuf->st_dev.old_abi;
+ buf->st_blocks = kbuf->__pad_st_blocks;
+ }
+#else
buf->st_dev = kbuf->st_dev;
buf->st_ino = kbuf->st_ino;
+ buf->st_rdev = kbuf->st_rdev;
+#endif
+
#ifdef _HAVE_STAT64___ST_INO
buf->__st_ino = kbuf->__st_ino;
#endif
+
buf->st_mode = kbuf->st_mode;
buf->st_nlink = kbuf->st_nlink;
buf->st_uid = kbuf->st_uid;
buf->st_gid = kbuf->st_gid;
- buf->st_rdev = kbuf->st_rdev;
buf->st_size = kbuf->st_size;
buf->st_blksize = kbuf->st_blksize;
- buf->st_blocks = kbuf->st_blocks;
buf->st_atime = kbuf->st_atime;
buf->st_mtime = kbuf->st_mtime;
buf->st_ctime = kbuf->st_ctime;
+
#ifdef STAT_HAVE_NSEC
buf->st_atime_nsec = kbuf->st_atime_nsec;
buf->st_mtime_nsec = kbuf->st_mtime_nsec;