fstatat: fix up behavior on 32/64 bit hosts

The fstatat() syscall is a little funky in that it sometimes changes name
between 32 and 64 bit hosts, but it should always operate on a 64bit stat
structure.  So for the fstatat() function, make sure we convert it from a
64bit kstat to a 32bit stat.

Along these lines, we need to restore the __xstat32_conv() function.

Reported-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

libc/sysdeps/linux/common/fstatat.c

@@ -10,15 +10,20 @@
 #include <sys/stat.h>
 #include "xstatconv.h"
 
+/* 64bit ports tend to favor newfstatat() */
+#ifdef __NR_newfstatat
+# define __NR_fstatat64 __NR_newfstatat
+#endif
+
 #ifdef __NR_fstatat64
 int fstatat(int fd, const char *file, struct stat *buf, int flag)
 {
 	int ret;
-	struct kernel_stat kbuf;
+	struct kernel_stat64 kbuf;
 
 	ret = INLINE_SYSCALL(fstatat64, 4, fd, file, &kbuf, flag);
 	if (ret == 0)
-		__xstat_conv(&kbuf, buf);
+		__xstat32_conv(&kbuf, buf);
 
 	return ret;
 }

libc/sysdeps/linux/common/fstatat64.c

@@ -12,6 +12,11 @@
 
 #ifdef __UCLIBC_HAS_LFS__
 
+/* 64bit ports tend to favor newfstatat() */
+#ifdef __NR_newfstatat
+# define __NR_fstatat64 __NR_newfstatat
+#endif
+
 #ifdef __NR_fstatat64
 int fstatat64(int fd, const char *file, struct stat64 *buf, int flag)
 {

libc/sysdeps/linux/common/xstatconv.c

@@ -44,6 +44,25 @@ void __xstat_conv(struct kernel_stat *kbuf, struct stat *buf)
 	buf->st_ctim = kbuf->st_ctim;
 }
 
+void __xstat32_conv(struct kernel_stat64 *kbuf, struct stat *buf)
+{
+	/* Convert to current kernel version of `struct stat64'. */
+	memset(buf, 0x00, sizeof(*buf));
+	buf->st_dev = kbuf->st_dev;
+	buf->st_ino = kbuf->st_ino;
+	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_atim = kbuf->st_atim;
+	buf->st_mtim = kbuf->st_mtim;
+	buf->st_ctim = kbuf->st_ctim;
+}
+
 #ifdef __UCLIBC_HAS_LFS__
 
 void __xstat64_conv(struct kernel_stat64 *kbuf, struct stat64 *buf)

libc/sysdeps/linux/common/xstatconv.h

@@ -26,6 +26,7 @@
 #include <bits/kernel_stat.h>
 
 extern void __xstat_conv(struct kernel_stat *kbuf, struct stat *buf) attribute_hidden;
+extern void __xstat32_conv(struct kernel_stat64 *kbuf, struct stat *buf) attribute_hidden;
 #if defined __UCLIBC_HAS_LFS__
 extern void __xstat64_conv(struct kernel_stat64 *kbuf, struct stat64 *buf) attribute_hidden;
 #endif