/*
* COPYRIGHT (c) 1989-2010.
* 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.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
/*
* This file implements the "mount" procedure for tar-based IMFS
* extensions. The TAR is not actually mounted under the IMFS.
* Directories from the TAR file are created as usual in the IMFS.
* File entries are created as IMFS_LINEAR_FILE nodes with their nods
* pointing to addresses in the TAR image.
*/
#include "imfs.h"
#include <sys/stat.h>
#include <string.h>
#include <tar.h>
#include <rtems/untar.h>
/*
* TAR file format:
*
* Offset Length Contents
* 0 100 bytes File name ('\0' terminated, 99 maxmum length)
* 100 8 bytes File mode (in octal ascii)
* 108 8 bytes User ID (in octal ascii)
* 116 8 bytes Group ID (in octal ascii)
* 124 12 bytes File size (s) (in octal ascii)
* 136 12 bytes Modify time (in octal ascii)
* 148 8 bytes Header checksum (in octal ascii)
* 156 1 bytes Link flag
* 157 100 bytes Linkname ('\0' terminated, 99 maxmum length)
* 257 8 bytes Magic PAX ("ustar\0" + 2 bytes padding)
* 257 8 bytes Magic GNU tar ("ustar \0")
* 265 32 bytes User name ('\0' terminated, 31 maxmum length)
* 297 32 bytes Group name ('\0' terminated, 31 maxmum length)
* 329 8 bytes Major device ID (in octal ascii)
* 337 8 bytes Minor device ID (in octal ascii)
* 345 167 bytes Padding
* 512 (s+p)bytes File contents (s+p) := (((s) + 511) & ~511),
* round up to 512 bytes
*
* Checksum:
* int i, sum;
* char* header = tar_header_pointer;
* sum = 0;
* for(i = 0; i < 512; i++)
* sum += 0xFF & header[i];
*/
#define MAX_NAME_FIELD_SIZE 99
#define MIN(a,b) ((a)>(b)?(b):(a))
/*
* rtems_tarfs_load
*
* Here we create the mountpoint directory and load the tarfs at
* that node. Once the IMFS has been mounted, we work through the
* tar image and perform as follows:
* - For directories, simply call mkdir(). The IMFS creates nodes as
* needed.
* - For files, we make our own calls to IMFS eval_for_make and
* create_node.
*/
int rtems_tarfs_load(
const char *mountpoint,
uint8_t *tar_image,
size_t tar_size
)
{
const char *hdr_ptr;
char filename[100];
char full_filename[256];
int hdr_chksum;
unsigned char linkflag;
unsigned long file_size;
unsigned long file_mode;
int offset;
unsigned long nblocks;
IMFS_jnode_t *node;
int rv = 0;
int eval_flags = RTEMS_LIBIO_FOLLOW_LINK;
rtems_filesystem_eval_path_context_t ctx;
rtems_filesystem_location_info_t rootloc;
rtems_filesystem_location_info_t *currentloc =
rtems_filesystem_eval_path_start( &ctx, mountpoint, eval_flags );
rtems_filesystem_eval_path_extract_currentloc( &ctx, &rootloc );
rtems_filesystem_eval_path_set_flags(
&ctx,
RTEMS_LIBIO_MAKE | RTEMS_LIBIO_EXCLUSIVE
);
if (rootloc.ops != &IMFS_ops && rootloc.ops != &fifoIMFS_ops) {
rv = -1;
}
/*
* Create an IMFS node structure pointing to tar image memory.
*/
offset = 0;
while ( rv == 0 ) {
if (offset + 512 > tar_size)
break;
/*
* Read a header.
*/
hdr_ptr = (char *) &tar_image[offset];
offset += 512;
if (strncmp(&hdr_ptr[257], "ustar", 5))
break;
strncpy(filename, hdr_ptr, MAX_NAME_FIELD_SIZE);
filename[MAX_NAME_FIELD_SIZE] = '\0';
linkflag = hdr_ptr[156];
file_mode = _rtems_octal2ulong(&hdr_ptr[100], 8);
file_size = _rtems_octal2ulong(&hdr_ptr[124], 12);
hdr_chksum = _rtems_octal2ulong(&hdr_ptr[148], 8);
if (_rtems_tar_header_checksum(hdr_ptr) != hdr_chksum)
break;
/*
* Generate an IMFS node depending on the file type.
* - For directories, just create directories as usual. IMFS
* will take care of the rest.
* - For files, create a file node with special tarfs properties.
*/
if (linkflag == DIRTYPE) {
strcpy(full_filename, mountpoint);
if (full_filename[strlen(full_filename)-1] != '/')
strcat(full_filename, "/");
strcat(full_filename, filename);
mkdir(full_filename, S_IRWXU | S_IRWXG | S_IRWXO);
}
/*
* Create a LINEAR_FILE node
*/
else if (linkflag == REGTYPE) {
rtems_filesystem_location_free( currentloc );
rtems_filesystem_location_clone( currentloc, &rootloc );
rtems_filesystem_eval_path_set_path(
&ctx,
filename,
strlen( filename )
);
rtems_filesystem_eval_path_continue( &ctx );
if ( !rtems_filesystem_location_is_null( currentloc ) ) {
node = IMFS_create_node(
currentloc,
IMFS_LINEAR_FILE,
rtems_filesystem_eval_path_get_token( &ctx ),
rtems_filesystem_eval_path_get_tokenlen( &ctx ),
(file_mode & (S_IRWXU | S_IRWXG | S_IRWXO)) | S_IFREG,
NULL
);
node->info.linearfile.size = file_size;
node->info.linearfile.direct = &tar_image[offset];
}
nblocks = (((file_size) + 511) & ~511) / 512;
offset += 512 * nblocks;
}
}
rtems_filesystem_location_free( &rootloc );
rtems_filesystem_eval_path_cleanup( &ctx );
return rv;
}
