| [PATCH 1/3] lutimesat: simplify utime(2) [message #9857] |
Fri, 26 January 2007 11:14  |
adobriyan
Messages: 80
Registered: November 2006
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Member |
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Rewrite via do_utimes() like compat_sys_utime().
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
---
fs/utimes.c | 50 +++++++-------------------------------------------
1 file changed, 7 insertions(+), 43 deletions(-)
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -22,52 +22,16 @@ #ifdef __ARCH_WANT_SYS_UTIME
*/
asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
{
- int error;
- struct nameidata nd;
- struct inode * inode;
- struct iattr newattrs;
+ struct timeval tv[2];
- error = user_path_walk(filename, &nd);
- if (error)
- goto out;
- inode = nd.dentry->d_inode;
-
- error = -EROFS;
- if (IS_RDONLY(inode))
- goto dput_and_out;
-
- /* Don't worry, the checks are done in inode_change_ok() */
- newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
if (times) {
- error = -EPERM;
- if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
- goto dput_and_out;
-
- error = get_user(newattrs.ia_atime.tv_sec, ×->actime);
- newattrs.ia_atime.tv_nsec = 0;
- if (!error)
- error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime);
- newattrs.ia_mtime.tv_nsec = 0;
- if (error)
- goto dput_and_out;
-
- newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
- } else {
- error = -EACCES;
- if (IS_IMMUTABLE(inode))
- goto dput_and_out;
-
- if (current->fsuid != inode->i_uid &&
- (error = vfs_permission(&nd, MAY_WRITE)) != 0)
- goto dput_and_out;
+ if (get_user(tv[0].tv_sec, ×->actime) ||
+ get_user(tv[1].tv_sec, ×->modtime))
+ return -EFAULT;
+ tv[0].tv_usec = 0;
+ tv[1].tv_usec = 0;
}
- mutex_lock(&inode->i_mutex);
- error = notify_change(nd.dentry, &newattrs);
- mutex_unlock(&inode->i_mutex);
-dput_and_out:
- path_release(&nd);
-out:
- return error;
+ return do_utimes(AT_FDCWD, filename, times ? tv : NULL);
}
#endif
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| Re: [PATCH 1/3] lutimesat: simplify utime(2) [message #9876 is a reply to message #9857] |
Fri, 26 January 2007 20:41  |
Andrew Morton
Messages: 127
Registered: December 2005
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Senior Member |
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On Fri, 26 Jan 2007 14:21:42 +0300
Alexey Dobriyan <adobriyan@openvz.org> wrote:
> Rewrite via do_utimes() like compat_sys_utime().
>
> Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
> ---
>
> fs/utimes.c | 50 +++++++-------------------------------------------
> 1 file changed, 7 insertions(+), 43 deletions(-)
>
> --- a/fs/utimes.c
> +++ b/fs/utimes.c
> @@ -22,52 +22,16 @@ #ifdef __ARCH_WANT_SYS_UTIME
> */
> asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
> {
> - int error;
> - struct nameidata nd;
> - struct inode * inode;
> - struct iattr newattrs;
> + struct timeval tv[2];
>
> - error = user_path_walk(filename, &nd);
> - if (error)
> - goto out;
> - inode = nd.dentry->d_inode;
> -
> - error = -EROFS;
> - if (IS_RDONLY(inode))
> - goto dput_and_out;
> -
> - /* Don't worry, the checks are done in inode_change_ok() */
> - newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
> if (times) {
> - error = -EPERM;
> - if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
> - goto dput_and_out;
> -
> - error = get_user(newattrs.ia_atime.tv_sec, ×->actime);
> - newattrs.ia_atime.tv_nsec = 0;
> - if (!error)
> - error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime);
> - newattrs.ia_mtime.tv_nsec = 0;
> - if (error)
> - goto dput_and_out;
> -
> - newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
> - } else {
> - error = -EACCES;
> - if (IS_IMMUTABLE(inode))
> - goto dput_and_out;
> -
> - if (current->fsuid != inode->i_uid &&
> - (error = vfs_permission(&nd, MAY_WRITE)) != 0)
> - goto dput_and_out;
> + if (get_user(tv[0].tv_sec, ×->actime) ||
> + get_user(tv[1].tv_sec, ×->modtime))
> + return -EFAULT;
> + tv[0].tv_usec = 0;
> + tv[1].tv_usec = 0;
> }
> - mutex_lock(&inode->i_mutex);
> - error = notify_change(nd.dentry, &newattrs);
> - mutex_unlock(&inode->i_mutex);
> -dput_and_out:
> - path_release(&nd);
> -out:
> - return error;
> + return do_utimes(AT_FDCWD, filename, times ? tv : NULL);
> }
>
> #endif
I'm somewhat surprised that this wasn't done earlier. I wonder if there's
some subtle reason why this won't work. How well tested is this?
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| Re: [PATCH 1/3] lutimesat: simplify utime(2) [message #9897 is a reply to message #9878] |
Sun, 28 January 2007 15:28 |
Alexey Dobriyan
Messages: 195
Registered: August 2006
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Senior Member |
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On Sat, Jan 27, 2007 at 12:35:42AM +0100, Arnd Bergmann wrote:
> On Friday 26 January 2007 21:41, Andrew Morton wrote:
> > I'm somewhat surprised that this wasn't done earlier. I wonder if there's
> > some subtle reason why this won't work. How well tested is this?
>
> http://www.opengroup.org/onlinepubs/000095399/functions/utim es.html
> lists a slight difference between utime and utimes in the handling
> of EPERM/EACCESS:
>
> > The utimes() function shall fail if:
> > [EACCES] Search permission is denied by a component of the path prefix;
> > or the times argument is a null pointer and the effective user ID of the
> > process does not match the owner of the file and write access is denied.
> > [EPERM] The times argument is not a null pointer and the calling process'
> > effective user ID has write access to the file but does not match the
> > owner of the file and the calling process does not have the appropriate
> > privileges.
> >
> > The utime() function shall fail if:
> > [EACCES] Search permission is denied by a component of the path prefix;
> > or the times argument is a null pointer and the effective user ID of the
> > process does not match the owner of the file, the process does not have
> > write permission for the file, and the process does not have appropriate
> > privileges.
> > [EPERM] The times argument is not a null pointer and the calling process'
> > effective user ID does not match the owner of the file and the calling
> > process does not have the appropriate privileges.
>
> I don't really understand how that should be implemented in different
> ways, but it might be the reason that we have separate functions.
Present sys_utime() and do_utimes() are identical, except the former
does direct getusering into new attributes, and the latter accept "int
dfd" instead of hardcoded current working directory.
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