minix/lib/libsffs/stat.c

   1 /* This file contains file metadata retrieval and manipulation routines.
   2  *
   3  * The entry points into this file are:
   4  *   get_mode           return a file's mode
   5  *   do_stat            perform the STAT file system call
   6  *   do_chmod           perform the CHMOD file system call
   7  *   do_utime           perform the UTIME file system call
   8  *
   9  * Created:
  10  *   April 2009 (D.C. van Moolenbroek)
  11  */
  12
  13 #include "inc.h"
  14
  15 /*===========================================================================*
  16  *                              get_mode                                     *
  17  *===========================================================================*/
  18 mode_t get_mode(struct inode *ino, int mode)
  19 {
  20 /* Return the mode for an inode, given the inode and the retrieved mode.
  21  */
  22
  23   mode &= S_IRWXU;
  24   mode = mode | (mode >> 3) | (mode >> 6);
  25
  26   if (IS_DIR(ino))
  27         mode = S_IFDIR | (mode & sffs_params->p_dir_mask);
  28   else
  29         mode = S_IFREG | (mode & sffs_params->p_file_mask);
  30
  31   if (read_only)
  32         mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
  33
  34   return mode;
  35 }
  36
  37 /*===========================================================================*
  38  *                              do_stat                                      *
  39  *===========================================================================*/
  40 int do_stat(ino_t ino_nr, struct stat *st)
  41 {
  42 /* Retrieve inode status.
  43  */
  44   struct inode *ino;
  45   struct sffs_attr attr;
  46   char path[PATH_MAX];
  47   int r;
  48
  49   /* Don't increase the inode refcount: it's already open anyway */
  50   if ((ino = find_inode(ino_nr)) == NULL)
  51         return EINVAL;
  52
  53   attr.a_mask = SFFS_ATTR_MODE | SFFS_ATTR_SIZE | SFFS_ATTR_CRTIME |
  54                 SFFS_ATTR_ATIME | SFFS_ATTR_MTIME | SFFS_ATTR_CTIME;
  55
  56   if ((r = verify_inode(ino, path, &attr)) != OK)
  57         return r;
  58
  59   st->st_mode = get_mode(ino, attr.a_mode);
  60   st->st_uid = sffs_params->p_uid;
  61   st->st_gid = sffs_params->p_gid;
  62   st->st_rdev = NO_DEV;
  63   st->st_size = attr.a_size;
  64   st->st_atimespec = attr.a_atime;
  65   st->st_mtimespec = attr.a_mtime;
  66   st->st_ctimespec = attr.a_ctime;
  67   st->st_birthtimespec = attr.a_crtime;
  68
  69   st->st_blocks = st->st_size / S_BLKSIZE;
  70   if (st->st_size % S_BLKSIZE != 0)
  71         st->st_blocks += 1;
  72
  73   st->st_blksize = BLOCK_SIZE;
  74
  75   /* We could make this more accurate by iterating over directory inodes'
  76    * children, counting how many of those are directories as well.
  77    * It's just not worth it.
  78    */
  79   st->st_nlink = 0;
  80   if (ino->i_parent != NULL) st->st_nlink++;
  81   if (IS_DIR(ino)) {
  82         st->st_nlink++;
  83         if (HAS_CHILDREN(ino)) st->st_nlink++;
  84   }
  85
  86   return OK;
  87 }
  88
  89 /*===========================================================================*
  90  *                              do_chmod                                     *
  91  *===========================================================================*/
  92 int do_chmod(ino_t ino_nr, mode_t *mode)
  93 {
  94 /* Change file mode.
  95  */
  96   struct inode *ino;
  97   char path[PATH_MAX];
  98   struct sffs_attr attr;
  99   int r;
 100
 101   if (read_only)
 102         return EROFS;
 103
 104   if ((ino = find_inode(ino_nr)) == NULL)
 105         return EINVAL;
 106
 107   if ((r = verify_inode(ino, path, NULL)) != OK)
 108         return r;
 109
 110   /* Set the new file mode. */
 111   attr.a_mask = SFFS_ATTR_MODE;
 112   attr.a_mode = *mode; /* no need to convert in this direction */
 113
 114   if ((r = sffs_table->t_setattr(path, &attr)) != OK)
 115         return r;
 116
 117   /* We have no idea what really happened. Query for the mode again. */
 118   if ((r = verify_path(path, ino, &attr, NULL)) != OK)
 119         return r;
 120
 121   *mode = get_mode(ino, attr.a_mode);
 122
 123   return OK;
 124 }
 125
 126 /*===========================================================================*
 127  *                              do_utime                                     *
 128  *===========================================================================*/
 129 int do_utime(ino_t ino_nr, struct timespec *atime, struct timespec *mtime)
 130 {
 131 /* Set file times.
 132  */
 133   struct inode *ino;
 134   char path[PATH_MAX];
 135   struct sffs_attr attr;
 136   int r;
 137
 138   if (read_only)
 139         return EROFS;
 140
 141   if ((ino = find_inode(ino_nr)) == NULL)
 142         return EINVAL;
 143
 144   if ((r = verify_inode(ino, path, NULL)) != OK)
 145         return r;
 146
 147   attr.a_mask = 0;
 148
 149   switch (atime->tv_nsec) {
 150   case UTIME_OMIT: /* do not touch */
 151         break;
 152   case UTIME_NOW:
 153         /* XXX VFS should have time() into ACTIME, for compat; we trust it! */
 154         atime->tv_nsec = 0;
 155         /*FALLTHROUGH*/
 156   default:
 157         attr.a_atime = *atime;
 158         attr.a_mask |= SFFS_ATTR_ATIME;
 159         break;
 160   }
 161
 162   switch (mtime->tv_nsec) {
 163   case UTIME_OMIT: /* do not touch */
 164         break;
 165   case UTIME_NOW:
 166         /* XXX VFS should have time() into MODTIME, for compat; we trust it! */
 167         mtime->tv_nsec = 0;
 168         /*FALLTHROUGH*/
 169   default:
 170         attr.a_mtime = *mtime;
 171         attr.a_mask |= SFFS_ATTR_MTIME;
 172         break;
 173   }
 174
 175   return sffs_table->t_setattr(path, &attr);
 176 }