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/*
* IMFS Directory Access Routines
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <chain.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <dirent.h>
#include "imfs.h"
#include <rtems/libio_.h>
/*
* imfs_dir_open
*
* This rountine will verify that the node being opened as a directory is
* in fact a directory node. If it is then the offset into the directory
* will be set to 0 to position to the first directory entry.
*/
int imfs_dir_open(
rtems_libio_t *iop,
const char *pathname,
unsigned32 flag,
unsigned32 mode
)
{
IMFS_jnode_t *the_jnode;
/* Is the node a directory ? */
the_jnode = (IMFS_jnode_t *) iop->file_info;
if ( the_jnode->type != IMFS_DIRECTORY )
return -1; /* It wasn't a directory --> return error */
iop->offset = 0;
return 0;
}
/*
* imfs_dir_read
*
* This routine will read the next directory entry based on the directory
* offset. The offset should be equal to -n- time the size of an individual
* dirent structure. If n is not an integer multiple of the sizeof a
* dirent structure, an integer division will be performed to determine
* directory entry that will be returned in the buffer. Count should reflect
* -m- times the sizeof dirent bytes to be placed in the buffer.
* If there are not -m- dirent elements from the current directory position
* to the end of the exisiting file, the remaining entries will be placed in
* the buffer and the returned value will be equal to -m actual- times the
* size of a directory entry.
*/
int imfs_dir_read(
rtems_libio_t *iop,
void *buffer,
unsigned32 count
)
{
/*
* Read up to element iop->offset in the directory chain of the
* imfs_jnode_t struct for this file descriptor.
*/
Chain_Node *the_node;
Chain_Control *the_chain;
IMFS_jnode_t *the_jnode;
int bytes_transferred;
int current_entry;
int first_entry;
int last_entry;
struct dirent tmp_dirent;
the_jnode = (IMFS_jnode_t *)iop->file_info;
the_chain = &the_jnode->info.directory.Entries;
if ( Chain_Is_empty( the_chain ) )
return 0;
/* Move to the first of the desired directory entries */
the_node = the_chain->first;
bytes_transferred = 0;
first_entry = iop->offset;
/* protect against using sizes that are not exact multiples of the */
/* -dirent- size. These could result in unexpected results */
last_entry = first_entry + (count/sizeof(struct dirent)) * sizeof(struct dirent);
/* The directory was not empty so try to move to the desired entry in chain*/
for (
current_entry = 0;
current_entry < last_entry;
current_entry = current_entry + sizeof(struct dirent) ){
if ( Chain_Is_tail( the_chain, the_node ) ){
/* We hit the tail of the chain while trying to move to the first */
/* entry in the read */
return bytes_transferred; /* Indicate that there are no more */
/* entries to return */
}
if( current_entry >= first_entry ) {
/* Move the entry to the return buffer */
tmp_dirent.d_off = current_entry;
tmp_dirent.d_reclen = sizeof( struct dirent );
the_jnode = (IMFS_jnode_t *) the_node;
tmp_dirent.d_ino = the_jnode->st_ino;
tmp_dirent.d_namlen = strlen( the_jnode->name );
strcpy( tmp_dirent.d_name, the_jnode->name );
memcpy(
buffer + bytes_transferred,
(void *)&tmp_dirent,
sizeof( struct dirent )
);
iop->offset = iop->offset + sizeof(struct dirent);
bytes_transferred = bytes_transferred + sizeof( struct dirent );
}
the_node = the_node->next;
}
/* Success */
return bytes_transferred;
}
/*
* imfs_dir_close
*
* This routine will be called by the generic close routine to cleanup any
* resources that have been allocated for the management of the file
*/
int imfs_dir_close(
rtems_libio_t *iop
)
{
/*
* The generic close routine handles the deallocation of the file control
* and associated memory. At present the imfs_dir_close simply
* returns a successful completion status.
*/
return 0;
}
/*
* imfs_dir_lseek
*
* This routine will behave in one of three ways based on the state of
* argument whence. Based on the state of its value the offset argument will
* be interpreted using one of the following methods:
*
* SEEK_SET - offset is the absolute byte offset from the start of the
* logical start of the dirent sequence that represents the
* directory
* SEEK_CUR - offset is used as the relative byte offset from the current
* directory position index held in the iop structure
* SEEK_END - N/A --> This will cause an assert.
*/
int imfs_dir_lseek(
rtems_libio_t *iop,
off_t offset,
int whence
)
{
off_t normal_offset;
normal_offset = (offset/sizeof(struct dirent)) * sizeof(struct dirent);
switch( whence ) {
case SEEK_SET: /* absolute move from the start of the file */
iop->offset = normal_offset;
break;
case SEEK_CUR: /* relative move */
iop->offset = iop->offset + normal_offset;
break;
case SEEK_END: /* Movement past the end of the directory via lseek */
/* is not a permitted operation */
default:
set_errno_and_return_minus_one( EINVAL );
break;
}
return 0;
}
/*
* imfs_dir_fstat
*
* This routine will obtain the following information concerning the current
* directory:
* st_dev 0ll
* st_ino 1
* st_mode mode extracted from the jnode
* st_nlink number of links to this node
* st_uid uid extracted from the jnode
* st_gid gid extracted from the jnode
* st_rdev 0ll
* st_size the number of bytes in the directory
* This is calculated by taking the number of entries
* in the directory and multiplying by the size of a
* dirent structure
* st_blksize 0
* st_blocks 0
* stat_atime time of last access
* stat_mtime time of last modification
* stat_ctime time of the last change
*
* This information will be returned to the calling function in a -stat- struct
*
*/
int imfs_dir_fstat(
rtems_filesystem_location_info_t *loc,
struct stat *buf
)
{
Chain_Node *the_node;
Chain_Control *the_chain;
IMFS_jnode_t *the_jnode;
the_jnode = (IMFS_jnode_t *) loc->node_access;
buf->st_dev = 0ll;
buf->st_ino = the_jnode->st_ino;
buf->st_mode = the_jnode->st_mode;
buf->st_nlink = the_jnode->st_nlink;
buf->st_uid = the_jnode->st_uid;
buf->st_gid = the_jnode->st_gid;
buf->st_rdev = 0ll;
buf->st_blksize = 0;
buf->st_blocks = 0;
buf->st_atime = the_jnode->stat_atime;
buf->st_mtime = the_jnode->stat_mtime;
buf->st_ctime = the_jnode->stat_ctime;
buf->st_size = 0;
the_chain = &the_jnode->info.directory.Entries;
/* Run through the chain and count the number of directory entries */
/* that are subordinate to this directory node */
for ( the_node = the_chain->first ;
!_Chain_Is_tail( the_chain, the_node ) ;
the_node = the_node->next ) {
buf->st_size = buf->st_size + sizeof( struct dirent );
}
return 0;
}
/*
* IMFS_dir_rmnod
*
* This routine is available from the optable to remove a node
* from the IMFS file system.
*/
int imfs_dir_rmnod(
rtems_filesystem_location_info_t *pathloc /* IN */
)
{
IMFS_jnode_t *the_jnode;
the_jnode = (IMFS_jnode_t *) pathloc->node_access;
/*
* You cannot remove a node that still has children
*/
if ( ! Chain_Is_empty( &the_jnode->info.directory.Entries ) )
set_errno_and_return_minus_one( ENOTEMPTY );
/*
* You cannot remove the file system root node.
*/
if ( pathloc->mt_entry->mt_fs_root.node_access == pathloc->node_access )
set_errno_and_return_minus_one( EBUSY );
/*
* You cannot remove a mountpoint.
*/
if ( the_jnode->info.directory.mt_fs != NULL )
set_errno_and_return_minus_one( EBUSY );
/*
* Take the node out of the parent's chain that contains this node
*/
if ( the_jnode->Parent != NULL ) {
Chain_Extract( (Chain_Node *) the_jnode );
the_jnode->Parent = NULL;
}
/*
* Decrement the link counter and see if we can free the space.
*/
the_jnode->st_nlink--;
IMFS_update_ctime( the_jnode );
/*
* The file cannot be open and the link must be less than 1 to free.
*/
if ( !rtems_libio_is_file_open( the_jnode ) && (the_jnode->st_nlink < 1) ) {
/*
* Is the rtems_filesystem_current is this node?
*/
if ( rtems_filesystem_current.node_access == pathloc->node_access )
rtems_filesystem_current.node_access = NULL;
/*
* Free memory associated with a memory file.
*/
free( the_jnode );
}
return 0;
}
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