fs/utimes.c

   1 #include <linux/compiler.h>
   2 #include <linux/fs.h>
   3 #include <linux/linkage.h>
   4 #include <linux/namei.h>
   5 #include <linux/utime.h>
   6 #include <asm/uaccess.h>
   7 #include <asm/unistd.h>
   8
   9 #ifdef __ARCH_WANT_SYS_UTIME
  10
  11 /*
  12  * sys_utime() can be implemented in user-level using sys_utimes().
  13  * Is this for backwards compatibility?  If so, why not move it
  14  * into the appropriate arch directory (for those architectures that
  15  * need it).
  16  */
  17
  18 /* If times==NULL, set access and modification to current time,
  19  * must be owner or have write permission.
  20  * Else, update from *times, must be owner or super user.
  21  */
  22 asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
  23 {
  24         int error;
  25         struct nameidata nd;
  26         struct inode * inode;
  27         struct iattr newattrs;
  28
  29         error = user_path_walk(filename, &nd);
  30         if (error)
  31                 goto out;
  32         inode = nd.dentry->d_inode;
  33
  34         error = -EROFS;
  35         if (IS_RDONLY(inode))
  36                 goto dput_and_out;
  37
  38         /* Don't worry, the checks are done in inode_change_ok() */
  39         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
  40         if (times) {
  41                 error = -EPERM;
  42                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
  43                         goto dput_and_out;
  44
  45                 error = get_user(newattrs.ia_atime.tv_sec, &times->actime);
  46                 newattrs.ia_atime.tv_nsec = 0;
  47                 if (!error)
  48                         error = get_user(newattrs.ia_mtime.tv_sec, &times->modtime);
  49                 newattrs.ia_mtime.tv_nsec = 0;
  50                 if (error)
  51                         goto dput_and_out;
  52
  53                 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
  54         } else {
  55                 error = -EACCES;
  56                 if (IS_IMMUTABLE(inode))
  57                         goto dput_and_out;
  58
  59                 if (current->fsuid != inode->i_uid &&
  60                     (error = vfs_permission(&nd, MAY_WRITE)) != 0)
  61                         goto dput_and_out;
  62         }
  63         mutex_lock(&inode->i_mutex);
  64         error = notify_change(nd.dentry, &newattrs);
  65         mutex_unlock(&inode->i_mutex);
  66 dput_and_out:
  67         path_release(&nd);
  68 out:
  69         return error;
  70 }
  71
  72 #endif
  73
  74 /* If times==NULL, set access and modification to current time,
  75  * must be owner or have write permission.
  76  * Else, update from *times, must be owner or super user.
  77  */
  78 long do_utimes(int dfd, char __user *filename, struct timeval *times)
  79 {
  80         int error;
  81         struct nameidata nd;
  82         struct inode * inode;
  83         struct iattr newattrs;
  84
  85         error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
  86
  87         if (error)
  88                 goto out;
  89         inode = nd.dentry->d_inode;
  90
  91         error = -EROFS;
  92         if (IS_RDONLY(inode))
  93                 goto dput_and_out;
  94
  95         /* Don't worry, the checks are done in inode_change_ok() */
  96         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
  97         if (times) {
  98                 error = -EPERM;
  99                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 100                         goto dput_and_out;
 101
 102                 newattrs.ia_atime.tv_sec = times[0].tv_sec;
 103                 newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
 104                 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
 105                 newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
 106                 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
 107         } else {
 108                 error = -EACCES;
 109                 if (IS_IMMUTABLE(inode))
 110                         goto dput_and_out;
 111
 112                 if (current->fsuid != inode->i_uid &&
 113                     (error = vfs_permission(&nd, MAY_WRITE)) != 0)
 114                         goto dput_and_out;
 115         }
 116         mutex_lock(&inode->i_mutex);
 117         error = notify_change(nd.dentry, &newattrs);
 118         mutex_unlock(&inode->i_mutex);
 119 dput_and_out:
 120         path_release(&nd);
 121 out:
 122         return error;
 123 }
 124
 125 asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
 126 {
 127         struct timeval times[2];
 128
 129         if (utimes && copy_from_user(&times, utimes, sizeof(times)))
 130                 return -EFAULT;
 131         return do_utimes(dfd, filename, utimes ? times : NULL);
 132 }
 133
 134 asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
 135 {
 136         return sys_futimesat(AT_FDCWD, filename, utimes);
 137 }