lib/libsffs/mount.c

   1 /* This file contains mount and unmount functionality.
   2  *
   3  * The entry points into this file are:
   4  *   do_readsuper       perform the READSUPER file system call
   5  *   do_unmount         perform the UNMOUNT file system call
   6  *
   7  * Created:
   8  *   April 2009 (D.C. van Moolenbroek)
   9  */
  10
  11 #include "inc.h"
  12
  13 /*===========================================================================*
  14  *                              do_readsuper                                 *
  15  *===========================================================================*/
  16 int do_readsuper()
  17 {
  18 /* Mount the file system.
  19  */
  20   char path[PATH_MAX];
  21   struct inode *ino;
  22   struct sffs_attr attr;
  23   int r;
  24
  25   dprintf(("%s: readsuper (dev %x, flags %x)\n",
  26         sffs_name, (dev_t) m_in.REQ_DEV, m_in.REQ_FLAGS));
  27
  28   if (m_in.REQ_FLAGS & REQ_ISROOT) {
  29         printf("%s: attempt to mount as root device\n", sffs_name);
  30
  31         return EINVAL;
  32   }
  33
  34   state.s_read_only = !!(m_in.REQ_FLAGS & REQ_RDONLY);
  35   state.s_dev = m_in.REQ_DEV;
  36
  37   init_dentry();
  38   ino = init_inode();
  39
  40   attr.a_mask = SFFS_ATTR_MODE | SFFS_ATTR_SIZE;
  41
  42   /* We cannot continue if we fail to get the properties of the root inode at
  43    * all, because we cannot guess the details of the root node to return to
  44    * VFS. Print a (hopefully) helpful error message, and abort the mount.
  45    */
  46   if ((r = verify_inode(ino, path, &attr)) != OK) {
  47         if (r == EAGAIN)
  48                 printf("%s: shared folders disabled\n", sffs_name);
  49         else if (sffs_params->p_prefix[0] && (r == ENOENT || r == EACCES))
  50                 printf("%s: unable to access the given prefix directory\n",
  51                         sffs_name);
  52         else
  53                 printf("%s: unable to access shared folders\n", sffs_name);
  54
  55         return r;
  56   }
  57
  58   m_out.RES_INODE_NR = INODE_NR(ino);
  59   m_out.RES_MODE = get_mode(ino, attr.a_mode);
  60   m_out.RES_FILE_SIZE_HI = ex64hi(attr.a_size);
  61   m_out.RES_FILE_SIZE_LO = ex64lo(attr.a_size);
  62   m_out.RES_UID = sffs_params->p_uid;
  63   m_out.RES_GID = sffs_params->p_gid;
  64   m_out.RES_DEV = NO_DEV;
  65   m_out.RES_CONREQS = 1;        /* We can handle only 1 request at a time */
  66
  67   state.s_mounted = TRUE;
  68
  69   return OK;
  70 }
  71
  72 /*===========================================================================*
  73  *                              do_unmount                                   *
  74  *===========================================================================*/
  75 int do_unmount()
  76 {
  77 /* Unmount the file system.
  78  */
  79   struct inode *ino;
  80
  81   dprintf(("%s: do_unmount\n", sffs_name));
  82
  83   /* Decrease the reference count of the root inode. */
  84   if ((ino = find_inode(ROOT_INODE_NR)) == NULL)
  85         return EINVAL;
  86
  87   put_inode(ino);
  88
  89   /* There should not be any referenced inodes anymore now. */
  90   if (have_used_inode())
  91         printf("%s: in-use inodes left at unmount time!\n", sffs_name);
  92
  93   state.s_mounted = FALSE;
  94
  95   return OK;
  96 }