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/sched.h>
   6 #include <linux/utime.h>
   7 #include <asm/uaccess.h>
   8 #include <asm/unistd.h>
   9
  10 #ifdef __ARCH_WANT_SYS_UTIME
  11
  12 /*
  13  * sys_utime() can be implemented in user-level using sys_utimes().
  14  * Is this for backwards compatibility?  If so, why not move it
  15  * into the appropriate arch directory (for those architectures that
  16  * need it).
  17  */
  18
  19 /* If times==NULL, set access and modification to current time,
  20  * must be owner or have write permission.
  21  * Else, update from *times, must be owner or super user.
  22  */
  23 asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
  24 {
  25         int error;
  26         struct nameidata nd;
  27         struct inode * inode;
  28         struct iattr newattrs;
  29
  30         error = user_path_walk(filename, &nd);
  31         if (error)
  32                 goto out;
  33         inode = nd.dentry->d_inode;
  34
  35         error = -EROFS;
  36         if (IS_RDONLY(inode))
  37                 goto dput_and_out;
  38
  39         /* Don't worry, the checks are done in inode_change_ok() */
  40         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
  41         if (times) {
  42                 error = -EPERM;
  43                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
  44                         goto dput_and_out;
  45
  46                 error = get_user(newattrs.ia_atime.tv_sec, &times->actime);
  47                 newattrs.ia_atime.tv_nsec = 0;
  48                 if (!error)
  49                         error = get_user(newattrs.ia_mtime.tv_sec, &times->modtime);
  50                 newattrs.ia_mtime.tv_nsec = 0;
  51                 if (error)
  52                         goto dput_and_out;
  53
  54                 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
  55         } else {
  56                 error = -EACCES;
  57                 if (IS_IMMUTABLE(inode))
  58                         goto dput_and_out;
  59
  60                 if (current->fsuid != inode->i_uid &&
  61                     (error = vfs_permission(&nd, MAY_WRITE)) != 0)
  62                         goto dput_and_out;
  63         }
  64         mutex_lock(&inode->i_mutex);
  65         error = notify_change(nd.dentry, &newattrs);
  66         mutex_unlock(&inode->i_mutex);
  67 dput_and_out:
  68         path_release(&nd);
  69 out:
  70         return error;
  71 }
  72
  73 #endif
  74
  75 /* If times==NULL, set access and modification to current time,
  76  * must be owner or have write permission.
  77  * Else, update from *times, must be owner or super user.
  78  */
  79 long do_utimes(int dfd, char __user *filename, struct timeval *times)
  80 {
  81         int error;
  82         struct nameidata nd;
  83         struct inode * inode;
  84         struct iattr newattrs;
  85
  86         error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
  87
  88         if (error)
  89                 goto out;
  90         inode = nd.dentry->d_inode;
  91
  92         error = -EROFS;
  93         if (IS_RDONLY(inode))
  94                 goto dput_and_out;
  95
  96         /* Don't worry, the checks are done in inode_change_ok() */
  97         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
  98         if (times) {
  99                 error = -EPERM;
 100                 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 101                         goto dput_and_out;
 102
 103                 newattrs.ia_atime.tv_sec = times[0].tv_sec;
 104                 newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
 105                 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
 106                 newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
 107                 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
 108         } else {
 109                 error = -EACCES;
 110                 if (IS_IMMUTABLE(inode))
 111                         goto dput_and_out;
 112
 113                 if (current->fsuid != inode->i_uid &&
 114                     (error = vfs_permission(&nd, MAY_WRITE)) != 0)
 115                         goto dput_and_out;
 116         }
 117         mutex_lock(&inode->i_mutex);
 118         error = notify_change(nd.dentry, &newattrs);
 119         mutex_unlock(&inode->i_mutex);
 120 dput_and_out:
 121         path_release(&nd);
 122 out:
 123         return error;
 124 }
 125
 126 asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
 127 {
 128         struct timeval times[2];
 129
 130         if (utimes && copy_from_user(&times, utimes, sizeof(times)))
 131                 return -EFAULT;
 132         return do_utimes(dfd, filename, utimes ? times : NULL);
 133 }
 134
 135 asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
 136 {
 137         return sys_futimesat(AT_FDCWD, filename, utimes);
 138 }