[PATCH] common/pread_write.c: backport fix for 64-bit handling of pread/pwrite

From: "Anthony G. Basile" <[email protected]>

Commit 458076d fixed the pread/pwrite syscalls for 64-bit ports on the
master branch, but the fix was not backported to the 0.9.33 branch.  This
patch backports the fix which is critical for e2fsprogs-1.42.12 and above.
The introduction of pread64()/pwrite64() in e2fsprogs' commit f00948a
broke fsck.ext3 and fsck.ext4 on uclibc-0.9.33, leading to potential
data corrupton. See

https://bugs.gentoo.org/show_bug.cgi?id=548950

http://git.kernel.org/cgit/fs/ext2/e2fsprogs.git/commit/?id=f00948ad1df100c7d616ef6fbf7609329a2e4001

Signed-off-by: Anthony G. Basile <[email protected]>
---
 libc/sysdeps/linux/common/pread_write.c | 120 +++++++++++++++++++-------------
 1 file changed, 71 insertions(+), 49 deletions(-)

diff --git a/libc/sysdeps/linux/common/pread_write.c b/libc/sysdeps/linux/common/pread_write.c
index 924509e..51d76a1 100644
--- a/libc/sysdeps/linux/common/pread_write.c
+++ b/libc/sysdeps/linux/common/pread_write.c
@@ -28,87 +28,109 @@
 #define LIBC_CANCEL_HANDLED()	/* Nothing.  */
 #endif
 
-extern __typeof(pread) __libc_pread;
-extern __typeof(pwrite) __libc_pwrite;
-#ifdef __UCLIBC_HAS_LFS__
-extern __typeof(pread64) __libc_pread64;
-extern __typeof(pwrite64) __libc_pwrite64;
-#endif
-
-#ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
+#ifdef __NR_pread64
 # undef __NR_pread
 # define __NR_pread __NR_pread64
 #endif
+#ifdef __NR_pwrite64
+# undef __NR_pwrite
+# define __NR_pwrite __NR_pwrite64
+#endif
 
-#include <bits/kernel_types.h>
-
-# define __NR___syscall_pread __NR_pread
+#ifndef MY_PREAD
+# ifdef __NR_pread
+#  define __NR___syscall_pread __NR_pread
+#  if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
+static _syscall6(ssize_t, __syscall_pread, int, fd, void *, buf,
+                 size_t, count, int, dummy, off_t, offset_hi, off_t, offset_lo)
+#   define MY_PREAD(fd, buf, count, offset) __syscall_pread(fd, buf, count, 0, OFF_HI_LO(offset))
+#   define MY_PREAD64(fd, buf, count, offset) __syscall_pread(fd, buf, count, 0, OFF64_HI_LO(offset))
+#  elif __WORDSIZE == 32
+static _syscall5(ssize_t, __syscall_pread, int, fd, void *, buf,
+                 size_t, count, off_t, offset_hi, off_t, offset_lo)
+#   define MY_PREAD(fd, buf, count, offset) __syscall_pread(fd, buf, count, OFF_HI_LO(offset))
+#   define MY_PREAD64(fd, buf, count, offset) __syscall_pread(fd, buf, count, OFF64_HI_LO(offset))
+#  else
+static _syscall4(ssize_t, __syscall_pread, int, fd, void *, buf,
+                 size_t, count, off_t, offset)
+#   define MY_PREAD(fd, buf, count, offset) __syscall_pread(fd, buf, count, offset)
+#   define MY_PREAD64(fd, buf, count, offset) __syscall_pread(fd, buf, count, offset)
+#  endif
+# endif
+#endif
 
-#if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
-static __inline__ _syscall6(ssize_t, __syscall_pread, int, fd, void *, buf,
-		 size_t, count, int, dummy, off_t, offset_hi, off_t, offset_lo)
-# define __syscall_pread(fd, buf, count, ...) __syscall_pread(fd, buf, count, 0, __VA_ARGS__)
-#else
-static __inline__ _syscall5(ssize_t, __syscall_pread, int, fd, void *, buf,
-		size_t, count, off_t, offset_hi, off_t, offset_lo)
+#ifndef MY_PWRITE
+# ifdef __NR_pwrite
+#  define __NR___syscall_pwrite __NR_pwrite
+#  if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
+static _syscall6(ssize_t, __syscall_pwrite, int, fd, const void *, buf,
+                 size_t, count, int, dummy, off_t, offset_hi, off_t, offset_lo)
+#   define MY_PWRITE(fd, buf, count, offset) __syscall_pwrite(fd, buf, count, 0, OFF_HI_LO(offset))
+#   define MY_PWRITE64(fd, buf, count, offset) __syscall_pwrite(fd, buf, count, 0, OFF64_HI_LO(offset))
+#  elif __WORDSIZE == 32
+static _syscall5(ssize_t, __syscall_pwrite, int, fd, const void *, buf,
+                 size_t, count, off_t, offset_hi, off_t, offset_lo)
+#   define MY_PWRITE(fd, buf, count, offset) __syscall_pwrite(fd, buf, count, OFF_HI_LO(offset))
+#   define MY_PWRITE64(fd, buf, count, offset) __syscall_pwrite(fd, buf, count, OFF64_HI_LO(offset))
+#  else
+static _syscall4(ssize_t, __syscall_pwrite, int, fd, const void *, buf,
+                 size_t, count, off_t, offset)
+#   define MY_PWRITE(fd, buf, count, offset) __syscall_pwrite(fd, buf, count, offset)
+#   define MY_PWRITE64(fd, buf, count, offset) __syscall_pwrite(fd, buf, count, offset)
+#  endif
+# endif
 #endif
 
 ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset)
 {
 	int oldtype = LIBC_CANCEL_ASYNC ();
-	int result = __syscall_pread(fd, buf, count, __LONG_LONG_PAIR(offset >> 31, offset));
+	int result = MY_PREAD(fd, buf, count, offset);
 	LIBC_CANCEL_RESET (oldtype);
 	return result;
 
 }
 weak_alias(__libc_pread,pread)
 
-# ifdef __UCLIBC_HAS_LFS__
-ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
+ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
 {
-	uint32_t low = offset & 0xffffffff;
-	uint32_t high = offset >> 32;
 	int oldtype = LIBC_CANCEL_ASYNC ();
-	int result = __syscall_pread(fd, buf, count, __LONG_LONG_PAIR(high, low));
+	int result = MY_PWRITE(fd, buf, count, offset);
 	LIBC_CANCEL_RESET (oldtype);
 	return result;
 }
-weak_alias(__libc_pread64,pread64)
-# endif /* __UCLIBC_HAS_LFS__  */
-
-#ifdef __NR_pwrite64             /* Newer kernels renamed but it's the same.  */
-# undef __NR_pwrite
-# define __NR_pwrite __NR_pwrite64
-#endif
-
-# define __NR___syscall_pwrite __NR_pwrite
-#if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
-static __inline__ _syscall6(ssize_t, __syscall_pwrite, int, fd, const void *, buf,
-		size_t, count, int, dummy, off_t, offset_hi, off_t, offset_lo)
-# define __syscall_pwrite(fd, buf, count, ...) __syscall_pwrite(fd, buf, count, 0, __VA_ARGS__)
-#else
-static __inline__ _syscall5(ssize_t, __syscall_pwrite, int, fd, const void *, buf,
-		size_t, count, off_t, offset_hi, off_t, offset_lo)
-#endif
+weak_alias(__libc_pwrite,pwrite)
 
-ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
+#ifdef __UCLIBC_HAS_LFS__
+# if __WORDSIZE == 32
+ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
 {
 	int oldtype = LIBC_CANCEL_ASYNC ();
-	int result = __syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR(offset >> 31, offset));
+	int result = MY_PREAD64(fd, buf, count, offset);
 	LIBC_CANCEL_RESET (oldtype);
 	return result;
 }
-weak_alias(__libc_pwrite,pwrite)
+weak_alias(__libc_pread64,pread64)
 
-# ifdef __UCLIBC_HAS_LFS__
 ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
 {
-	uint32_t low = offset & 0xffffffff;
-	uint32_t high = offset >> 32;
 	int oldtype = LIBC_CANCEL_ASYNC ();
-	int result = __syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR(high, low));
+	int result = MY_PWRITE64(fd, buf, count, offset);
 	LIBC_CANCEL_RESET (oldtype);
 	return result;
 }
 weak_alias(__libc_pwrite64,pwrite64)
-# endif /* __UCLIBC_HAS_LFS__  */
+
+# else
+#  ifdef __LINUXTHREADS_OLD__
+weak_alias(pread,pread64)
+weak_alias(pwrite,pwrite64)
+extern __typeof(pread64) __libc_pread64;
+extern __typeof(pwrite64) __libc_pwrite4;
+strong_alias(pread64,__libc_pread64)
+strong_alias(pwrite64,__libc_write64)
+#  else
+strong_alias_untyped(pread,pread64)
+strong_alias_untyped(pwrite,pwrite64)
+#  endif
+# endif
+#endif
-- 
2.3.6