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(ino, mode)
  19 struct inode *ino;
  20 int mode;
  21 {
  22 /* Return the mode for an inode, given the inode and the retrieved mode.
  23  */
  24
  25   mode &= S_IRWXU;
  26   mode = mode | (mode >> 3) | (mode >> 6);
  27
  28   if (IS_DIR(ino))
  29         mode = S_IFDIR | (mode & sffs_params->p_dir_mask);
  30   else
  31         mode = S_IFREG | (mode & sffs_params->p_file_mask);
  32
  33   if (state.s_read_only)
  34         mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
  35
  36   return mode;
  37 }
  38
  39 /*===========================================================================*
  40  *                              do_stat                                      *
  41  *===========================================================================*/
  42 int do_stat()
  43 {
  44 /* Retrieve inode status.
  45  */
  46   struct inode *ino;
  47   struct sffs_attr attr;
  48   struct stat stat;
  49   char path[PATH_MAX];
  50   ino_t ino_nr;
  51   int r;
  52
  53   ino_nr = m_in.REQ_INODE_NR;
  54
  55   /* Don't increase the inode refcount: it's already open anyway */
  56   if ((ino = find_inode(ino_nr)) == NULL)
  57         return EINVAL;
  58
  59   attr.a_mask = SFFS_ATTR_MODE | SFFS_ATTR_SIZE | SFFS_ATTR_CRTIME |
  60                 SFFS_ATTR_ATIME | SFFS_ATTR_MTIME | SFFS_ATTR_CTIME;
  61
  62   if ((r = verify_inode(ino, path, &attr)) != OK)
  63         return r;
  64
  65   memset(&stat, 0, sizeof(struct stat));
  66
  67   stat.st_dev = state.s_dev;
  68   stat.st_ino = ino_nr;
  69   stat.st_mode = get_mode(ino, attr.a_mode);
  70   stat.st_uid = sffs_params->p_uid;
  71   stat.st_gid = sffs_params->p_gid;
  72   stat.st_rdev = NO_DEV;
  73   if (cmp64u(attr.a_size, LONG_MAX) > 0)
  74         stat.st_size = LONG_MAX;
  75   else
  76         stat.st_size = ex64lo(attr.a_size);
  77   stat.st_atimespec = attr.a_atime;
  78   stat.st_mtimespec = attr.a_mtime;
  79   stat.st_ctimespec = attr.a_ctime;
  80   stat.st_birthtimespec = attr.a_crtime;
  81
  82   stat.st_blocks = stat.st_size / S_BLKSIZE;
  83   if (stat.st_size % S_BLKSIZE != 0)
  84         stat.st_blocks += 1;
  85
  86   stat.st_blksize = BLOCK_SIZE;
  87
  88   /* We could make this more accurate by iterating over directory inodes'
  89    * children, counting how many of those are directories as well.
  90    * It's just not worth it.
  91    */
  92   stat.st_nlink = 0;
  93   if (ino->i_parent != NULL) stat.st_nlink++;
  94   if (IS_DIR(ino)) {
  95         stat.st_nlink++;
  96         if (HAS_CHILDREN(ino)) stat.st_nlink++;
  97   }
  98
  99   return sys_safecopyto(m_in.m_source, m_in.REQ_GRANT, 0,
 100         (vir_bytes) &stat, sizeof(stat));
 101 }
 102
 103 /*===========================================================================*
 104  *                              do_chmod                                     *
 105  *===========================================================================*/
 106 int do_chmod()
 107 {
 108 /* Change file mode.
 109  */
 110   struct inode *ino;
 111   char path[PATH_MAX];
 112   struct sffs_attr attr;
 113   int r;
 114
 115   if (state.s_read_only)
 116         return EROFS;
 117
 118   if ((ino = find_inode(m_in.REQ_INODE_NR)) == NULL)
 119         return EINVAL;
 120
 121   if ((r = verify_inode(ino, path, NULL)) != OK)
 122         return r;
 123
 124   /* Set the new file mode. */
 125   attr.a_mask = SFFS_ATTR_MODE;
 126   attr.a_mode = m_in.REQ_MODE; /* no need to convert in this direction */
 127
 128   if ((r = sffs_table->t_setattr(path, &attr)) != OK)
 129         return r;
 130
 131   /* We have no idea what really happened. Query for the mode again. */
 132   if ((r = verify_path(path, ino, &attr, NULL)) != OK)
 133         return r;
 134
 135   m_out.RES_MODE = get_mode(ino, attr.a_mode);
 136
 137   return OK;
 138 }
 139
 140 /*===========================================================================*
 141  *                              do_utime                                     *
 142  *===========================================================================*/
 143 int do_utime()
 144 {
 145 /* Set file times.
 146  */
 147   struct inode *ino;
 148   char path[PATH_MAX];
 149   struct sffs_attr attr;
 150   int r;
 151
 152   if (state.s_read_only)
 153         return EROFS;
 154
 155   if ((ino = find_inode(m_in.REQ_INODE_NR)) == NULL)
 156         return EINVAL;
 157
 158   if ((r = verify_inode(ino, path, NULL)) != OK)
 159         return r;
 160
 161   attr.a_mask = SFFS_ATTR_ATIME | SFFS_ATTR_MTIME;
 162   attr.a_atime.tv_sec = m_in.REQ_ACTIME;
 163   attr.a_atime.tv_nsec = 0;
 164   attr.a_mtime.tv_sec = m_in.REQ_MODTIME;
 165   attr.a_mtime.tv_nsec = 0;
 166
 167   return sffs_table->t_setattr(path, &attr);
 168 }