[PATCH] fstatat64 support

The *at patches introduced fstatat and, due to inusfficient research, I
used the newfstat functions generally as the guideline.  The result is that
on 32-bit platforms we don't have all the information needed to implement
fstatat64.

This patch modifies the code to pass up 64-bit information if
__ARCH_WANT_STAT64 is defined.  I renamed the syscall entry point to make
this clear.  Other archs will continue to use the existing code.  On x86-64
the compat code is implemented using a new sys32_ function.  this is what
is done for the other stat syscalls as well.

This patch might break some other archs (those which define
__ARCH_WANT_STAT64 and which already wired up the syscall).  Yet others
might need changes to accomodate the compatibility mode.  I really don't
want to do that work because all this stat handling is a mess (more so in
glibc, but the kernel is also affected).  It should be done by the arch
maintainers.  I'll provide some stand-alone test shortly.  Those who are
eager could compile glibc and run 'make check' (no installation needed).

The patch below has been tested on x86 and x86-64.

Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index 5a8b3fb..ac687d0 100644 (file)
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -299,7 +299,7 @@ ENTRY(sys_call_table)
        .long sys_mknodat
        .long sys_fchownat
        .long sys_futimesat
-       .long sys_newfstatat            /* 300 */
+       .long sys_fstatat64             /* 300 */
        .long sys_unlinkat
        .long sys_renameat
        .long sys_linkat

diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index ada4535..00dee17 100644 (file)
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -677,7 +677,7 @@ ia32_sys_call_table:
        .quad sys_mknodat
        .quad sys_fchownat
        .quad compat_sys_futimesat
-       .quad compat_sys_newfstatat     /* 300 */
+       .quad sys32_fstatat             /* 300 */
        .quad sys_unlinkat
        .quad sys_renameat
        .quad sys_linkat

diff --git a/arch/x86_64/ia32/sys_ia32.c b/arch/x86_64/ia32/sys_ia32.c
index 54481af..2bc55af 100644 (file)
--- a/arch/x86_64/ia32/sys_ia32.c
+++ b/arch/x86_64/ia32/sys_ia32.c
@@ -180,6 +180,28 @@ sys32_fstat64(unsigned int fd, struct stat64 __user *statbuf)
        return ret;
 }
 
+asmlinkage long
+sys32_fstatat(unsigned int dfd, char __user *filename,
+             struct stat64 __user* statbuf, int flag)
+{
+       struct kstat stat;
+       int error = -EINVAL;
+
+       if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
+               goto out;
+
+       if (flag & AT_SYMLINK_NOFOLLOW)
+               error = vfs_lstat_fd(dfd, filename, &stat);
+       else
+               error = vfs_stat_fd(dfd, filename, &stat);
+
+       if (!error)
+               error = cp_stat64(statbuf, &stat);
+
+out:
+       return error;
+}
+
 /*
  * Linux/i386 didn't use to be able to handle more than
  * 4 system call parameters, so these system calls used a memory

diff --git a/fs/stat.c b/fs/stat.c
index 24211b0..9948cc1 100644 (file)
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -261,6 +261,7 @@ asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf)
        return error;
 }
 
+#ifndef __ARCH_WANT_STAT64
 asmlinkage long sys_newfstatat(int dfd, char __user *filename,
                                struct stat __user *statbuf, int flag)
 {
@@ -281,6 +282,7 @@ asmlinkage long sys_newfstatat(int dfd, char __user *filename,
 out:
        return error;
 }
+#endif
 
 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf)
 {
@@ -395,6 +397,26 @@ asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf)
        return error;
 }
 
+asmlinkage long sys_fstatat64(int dfd, char __user *filename,
+                              struct stat64 __user *statbuf, int flag)
+{
+       struct kstat stat;
+       int error = -EINVAL;
+
+       if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
+               goto out;
+
+       if (flag & AT_SYMLINK_NOFOLLOW)
+               error = vfs_lstat_fd(dfd, filename, &stat);
+       else
+               error = vfs_stat_fd(dfd, filename, &stat);
+
+       if (!error)
+               error = cp_new_stat64(&stat, statbuf);
+
+out:
+       return error;
+}
 #endif /* __ARCH_WANT_STAT64 */
 
 void inode_add_bytes(struct inode *inode, loff_t bytes)

diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index cf6f2cd..dc81a55 100644 (file)
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -305,7 +305,7 @@
 #define __NR_mknodat           297
 #define __NR_fchownat          298
 #define __NR_futimesat         299
-#define __NR_newfstatat                300
+#define __NR_fstatat64         300
 #define __NR_unlinkat          301
 #define __NR_renameat          302
 #define __NR_linkat            303

diff --git a/include/asm-x86_64/ia32_unistd.h b/include/asm-x86_64/ia32_unistd.h
index 2046898..eeb2bcd 100644 (file)
--- a/include/asm-x86_64/ia32_unistd.h
+++ b/include/asm-x86_64/ia32_unistd.h
@@ -305,7 +305,7 @@
 #define __NR_ia32_mknodat              297
 #define __NR_ia32_fchownat             298
 #define __NR_ia32_futimesat            299
-#define __NR_ia32_newfstatat           300
+#define __NR_ia32_fstatat64            300
 #define __NR_ia32_unlinkat             301
 #define __NR_ia32_renameat             302
 #define __NR_ia32_linkat               303

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3877209..d73501b 100644 (file)
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -557,6 +557,8 @@ asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
                           int mode);
 asmlinkage long sys_newfstatat(int dfd, char __user *filename,
                               struct stat __user *statbuf, int flag);
+asmlinkage long sys_fstatat64(int dfd, char __user *filename,
+                              struct stat64 __user *statbuf, int flag);
 asmlinkage long sys_readlinkat(int dfd, const char __user *path, char __user *buf,
                               int bufsiz);
 asmlinkage long compat_sys_futimesat(unsigned int dfd, char __user *filename,