utimes.c
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#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/utime.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#ifdef __ARCH_WANT_SYS_UTIME
/*
* sys_utime() can be implemented in user-level using sys_utimes().
* Is this for backwards compatibility? If so, why not move it
* into the appropriate arch directory (for those architectures that
* need it).
*/
/* If times==NULL, set access and modification to current time,
* must be owner or have write permission.
* Else, update from *times, must be owner or super user.
*/
asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
{
int error;
struct nameidata nd;
struct inode * inode;
struct iattr newattrs;
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;
}
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;
}
#endif
/* If times==NULL, set access and modification to current time,
* must be owner or have write permission.
* Else, update from *times, must be owner or super user.
*/
long do_utimes(int dfd, char __user *filename, struct timeval *times)
{
int error;
struct nameidata nd;
struct inode * inode;
struct iattr newattrs;
error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &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;
newattrs.ia_atime.tv_sec = times[0].tv_sec;
newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
newattrs.ia_mtime.tv_sec = times[1].tv_sec;
newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
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;
}
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;
}
asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
{
struct timeval times[2];
if (utimes && copy_from_user(×, utimes, sizeof(times)))
return -EFAULT;
return do_utimes(dfd, filename, utimes ? times : NULL);
}
asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
{
return sys_futimesat(AT_FDCWD, filename, utimes);
}