/* MDB Tools - A library for reading MS Access database files
* Copyright (C) 2000 Brian Bruns
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "../mdbtools.h"
#ifdef DMALLOC
#include "dmalloc.h"
#endif
/*
typedef struct {
int pg_size;
guint16 row_count_offset;
guint16 tab_num_rows_offset;
guint16 tab_num_cols_offset;
guint16 tab_num_idxs_offset;
guint16 tab_num_ridxs_offset;
guint16 tab_usage_map_offset;
guint16 tab_first_dpg_offset;
guint16 tab_cols_start_offset;
guint16 tab_ridx_entry_size;
guint16 col_flags_offset;
guint16 col_size_offset;
guint16 col_num_offset;
guint16 tab_col_entry_size;
guint16 tab_free_map_offset;
guint16 tab_col_offset_var;
guint16 tab_col_offset_fixed;
guint16 tab_row_col_num_offset;
} MdbFormatConstants;
*/
MdbFormatConstants MdbJet4Constants = {
4096, 0x0c, 16, 45, 47, 51, 55, 56, 63, 12, 15, 23, 5, 25, 59, 7, 21, 9
};
MdbFormatConstants MdbJet3Constants = {
2048, 0x08, 12, 25, 27, 31, 35, 36, 43, 8, 13, 16, 1, 18, 39, 3, 14, 5
};
typedef struct _RC4_KEY
{
unsigned char state[256];
unsigned char x;
unsigned char y;
} RC4_KEY;
#define swap_byte(x,y) t = *(x); *(x) = *(y); *(y) = t
static size_t _mdb_read_pg(MdbHandle *mdb, void *pg_buf, unsigned long pg);
static void RC4_set_key(RC4_KEY *key, int key_data_len, unsigned char *key_data_ptr)
{
unsigned char t;
unsigned char index1;
unsigned char index2;
unsigned char* state;
short counter;
state = &key->state[0];
for(counter = 0; counter < 256; counter++)
state[counter] = counter;
key->x = 0;
key->y = 0;
index1 = 0;
index2 = 0;
for(counter = 0; counter < 256; counter++) {
index2 = (key_data_ptr[index1] + state[counter] + index2) % 256;
swap_byte(&state[counter], &state[index2]);
index1 = (index1 + 1) % key_data_len;
}
}
/*
* this algorithm does 'encrypt in place' instead of inbuff/outbuff
* note also: encryption and decryption use same routine
* implementation supplied by (Adam Back) at <adam at cypherspace dot org>
*/
static void RC4(RC4_KEY *key, int buffer_len, unsigned char * buff)
{
unsigned char t;
unsigned char x;
unsigned char y;
unsigned char* state;
unsigned char xorIndex;
short counter;
x = key->x;
y = key->y;
state = &key->state[0];
for(counter = 0; counter < buffer_len; counter++) {
x = (x + 1) % 256;
y = (state[x] + y) % 256;
swap_byte(&state[x], &state[y]);
xorIndex = (state[x] + state[y]) % 256;
buff[counter] ^= state[xorIndex];
}
key->x = x;
key->y = y;
}
/**
* mdb_find_file:
* @filename: path to MDB (database) file
*
* Finds and returns the absolute path to an MDB file. Function will first try
* to fstat file as passed, then search through the $MDBPATH if not found.
*
* Return value: gchar pointer to absolute path. Caller is responsible for
* freeing.
**/
static char *mdb_find_file(const char *file_name)
{
struct stat status;
gchar *mdbpath, **dir, *tmpfname;
unsigned int i = 0;
/* try the provided file name first */
if (!stat(file_name, &status)) {
return g_strdup(file_name);
}
/* Now pull apart $MDBPATH and try those */
mdbpath = (gchar *) getenv("MDBPATH");
/* no path, can't find file */
if (!mdbpath || !strlen(mdbpath)) return NULL;
dir = g_strsplit(mdbpath, ":", 0);
while (dir[i]) {
if (!strlen(dir[i])) continue;
tmpfname = g_strconcat(dir[i++], "/", file_name, NULL);
if (!stat(tmpfname, &status)) {
g_strfreev(dir);
return tmpfname;
}
g_free(tmpfname);
}
g_strfreev(dir);
return NULL;
}
/**
* mdb_open:
* @filename: path to MDB (database) file
* @flags: MDB_NOFLAGS for read-only, MDB_WRITABLE for read/write
*
* Opens an MDB file and returns an MdbHandle to it. MDB File may be relative
* to the current directory, a full path to the file, or relative to a
* component of $MDBPATH.
*
* Return value: pointer to MdbHandle structure.
**/
MdbHandle *mdb_open(const char *filename, MdbFileFlags flags)
{
MdbHandle *mdb;
int key[] = {0x86, 0xfb, 0xec, 0x37, 0x5d, 0x44, 0x9c, 0xfa, 0xc6, 0x5e, 0x28, 0xe6, 0x13, 0xb6};
int j, pos;
int open_flags;
mdb = (MdbHandle *) g_malloc0(sizeof(MdbHandle));
mdb_set_default_backend(mdb, "access");
#ifdef HAVE_ICONV
mdb->iconv_in = (iconv_t)-1;
mdb->iconv_out = (iconv_t)-1;
#endif
/* need something to bootstrap with, reassign after page 0 is read */
mdb->fmt = &MdbJet3Constants;
mdb->f = (MdbFile *) g_malloc0(sizeof(MdbFile));
mdb->f->refs = 1;
mdb->f->fd = -1;
mdb->f->filename = mdb_find_file(filename);
if (!mdb->f->filename) {
fprintf(stderr, "Can't alloc filename\n");
mdb_close(mdb);
return NULL;
}
if (flags & MDB_WRITABLE) {
mdb->f->writable = TRUE;
open_flags = O_RDWR;
} else {
open_flags = O_RDONLY;
}
#ifdef _WIN32
open_flags |= O_BINARY;
#endif
mdb->f->fd = open(mdb->f->filename, open_flags);
if (mdb->f->fd==-1) {
fprintf(stderr,"Couldn't open file %s\n",mdb->f->filename);
mdb_close(mdb);
return NULL;
}
if (!mdb_read_pg(mdb, 0)) {
fprintf(stderr,"Couldn't read first page.\n");
mdb_close(mdb);
return NULL;
}
if (mdb->pg_buf[0] != 0) {
mdb_close(mdb);
return NULL;
}
mdb->f->jet_version = mdb_get_int32(mdb->pg_buf, 0x14);
if (IS_JET4(mdb)) {
mdb->fmt = &MdbJet4Constants;
} else if (IS_JET3(mdb)) {
mdb->fmt = &MdbJet3Constants;
} else {
fprintf(stderr,"Unknown Jet version.\n");
mdb_close(mdb);
return NULL;
}
mdb->f->db_key = mdb_get_int32(mdb->pg_buf, 0x3e);
/* I don't know if this value is valid for some versions?
* it doesn't seem to be valid for the databases I have
*
* f->db_key ^= 0xe15e01b9;
*/
mdb->f->db_key ^= 0x4ebc8afb;
/* fprintf(stderr, "Encrypted file, RC4 key seed= %d\n", mdb->f->db_key); */
if (mdb->f->db_key) {
/* write is not supported for encrypted files yet */
mdb->f->writable = FALSE;
/* that should be enought, but reopen the file read only just to be
* sure we don't write invalid data */
close(mdb->f->fd);
open_flags = O_RDONLY;
#ifdef _WIN32
open_flags |= O_BINARY;
#endif
mdb->f->fd = open(mdb->f->filename, open_flags);
if (mdb->f->fd==-1) {
fprintf(stderr, "Couldn't ropen file %s in read only\n", mdb->f->filename);
mdb_close(mdb);
return NULL;
}
}
/* get the db password located at 0x42 bytes into the file */
for (pos=0;pos<14;pos++) {
j = mdb_get_int32(mdb,0x42+pos);
j ^= key[pos];
if ( j != 0)
mdb->f->db_passwd[pos] = j;
else
mdb->f->db_passwd[pos] = '\0';
}
mdb_iconv_init(mdb);
return mdb;
}
/**
* mdb_close:
* @mdb: Handle to open MDB database file
*
* Dereferences MDB file, closes if reference count is 0, and destroys handle.
*
**/
void
mdb_close(MdbHandle *mdb)
{
if (!mdb) return;
mdb_free_catalog(mdb);
g_free(mdb->stats);
g_free(mdb->backend_name);
if (mdb->f) {
if (mdb->f->refs > 1) {
mdb->f->refs--;
} else {
if (mdb->f->fd != -1) close(mdb->f->fd);
g_free(mdb->f->filename);
g_free(mdb->f);
}
}
mdb_iconv_close(mdb);
g_free(mdb);
}
/**
* mdb_clone_handle:
* @mdb: Handle to open MDB database file
*
* Clones an existing database handle. Cloned handle shares the file descriptor
* but has its own page buffer, page position, and similar internal variables.
*
* Return value: new handle to the database.
*/
MdbHandle *mdb_clone_handle(MdbHandle *mdb)
{
MdbHandle *newmdb;
MdbCatalogEntry *entry, *data;
unsigned int i;
newmdb = (MdbHandle *) g_memdup(mdb, sizeof(MdbHandle));
newmdb->stats = NULL;
newmdb->catalog = g_ptr_array_new();
for (i=0;i<mdb->num_catalog;i++) {
entry = g_ptr_array_index(mdb->catalog,i);
data = g_memdup(entry,sizeof(MdbCatalogEntry));
g_ptr_array_add(newmdb->catalog, data);
}
mdb->backend_name = NULL;
if (mdb->f) {
mdb->f->refs++;
}
mdb_iconv_init(mdb);
return newmdb;
}
/*
** mdb_read a wrapper for read that bails if anything is wrong
*/
size_t mdb_read_pg(MdbHandle *mdb, unsigned long pg)
{
size_t len;
if (pg && mdb->cur_pg == pg) return mdb->fmt->pg_size;
len = _mdb_read_pg(mdb, mdb->pg_buf, pg);
//fprintf(stderr, "read page %d type %02x\n", pg, mdb->pg_buf[0]);
mdb->cur_pg = pg;
/* kan - reset the cur_pos on a new page read */
mdb->cur_pos = 0; /* kan */
return len;
}
size_t mdb_read_alt_pg(MdbHandle *mdb, unsigned long pg)
{
size_t len;
len = _mdb_read_pg(mdb, mdb->alt_pg_buf, pg);
return len;
}
static size_t _mdb_read_pg(MdbHandle *mdb, void *pg_buf, unsigned long pg)
{
size_t len;
struct stat status;
off_t offset = pg * mdb->fmt->pg_size;
fstat(mdb->f->fd, &status);
if (status.st_size < offset) {
fprintf(stderr,"offset %lu is beyond EOF\n",offset);
return 0;
}
if (mdb->stats && mdb->stats->collect)
mdb->stats->pg_reads++;
lseek(mdb->f->fd, offset, SEEK_SET);
len = read(mdb->f->fd,pg_buf,mdb->fmt->pg_size);
if (len==-1) {
perror("read");
return 0;
}
else if (len<mdb->fmt->pg_size) {
/* fprintf(stderr,"EOF reached %d bytes returned.\n",len, mdb->fmt->pg_size); */
return 0;
}
/*
* unencrypt the page if necessary.
* it might make sense to cache the unencrypted data blocks?
*/
if (pg != 0 && mdb->f->db_key != 0)
{
RC4_KEY rc4_key;
unsigned int tmp_key = mdb->f->db_key ^ pg;
RC4_set_key(&rc4_key, 4, (unsigned char *)&tmp_key);
RC4(&rc4_key, mdb->fmt->pg_size, pg_buf);
}
return len;
}
void mdb_swap_pgbuf(MdbHandle *mdb)
{
char tmpbuf[MDB_PGSIZE];
memcpy(tmpbuf,mdb->pg_buf, MDB_PGSIZE);
memcpy(mdb->pg_buf,mdb->alt_pg_buf, MDB_PGSIZE);
memcpy(mdb->alt_pg_buf,tmpbuf,MDB_PGSIZE);
}
unsigned char mdb_get_byte(void *buf, int offset)
{
return ((unsigned char *)(buf))[offset];
}
unsigned char mdb_pg_get_byte(MdbHandle *mdb, int offset)
{
if (offset < 0 || offset+1 > mdb->fmt->pg_size) return -1;
mdb->cur_pos++;
return mdb->pg_buf[offset];
}
int mdb_get_int16(char *buf, int offset)
{
guint16 l;
memcpy(&l, buf + offset, 2);
return (int)GUINT16_FROM_LE(l);
}
int mdb_pg_get_int16(MdbHandle *mdb, int offset)
{
if (offset < 0 || offset+2 > mdb->fmt->pg_size) return -1;
mdb->cur_pos+=2;
return mdb_get_int16(mdb->pg_buf, offset);
}
long mdb_get_int32_msb(char *buf, int offset)
{
gint32 l;
memcpy(&l, buf + offset, 4);
return (long)GINT32_FROM_BE(l);
}
long mdb_get_int32(char *buf, int offset)
{
gint32 l;
memcpy(&l, buf + offset, 4);
return (long)GINT32_FROM_LE(l);
}
long mdb_pg_get_int32(MdbHandle *mdb, int offset)
{
if (offset <0 || offset+4 > mdb->fmt->pg_size) return -1;
mdb->cur_pos+=4;
return mdb_get_int32(mdb->pg_buf, offset);
}
float mdb_get_single(char *buf, int offset)
{
union {guint32 g; float f;} f;
memcpy(&f, buf + offset, 4);
f.g = GUINT32_FROM_LE(f.g);
return f.f;
}
float mdb_pg_get_single(MdbHandle *mdb, int offset)
{
if (offset <0 || offset+4 > mdb->fmt->pg_size) return -1;
mdb->cur_pos+=4;
return mdb_get_single(mdb->pg_buf, offset);
}
double mdb_get_double(char *buf, int offset)
{
union {guint64 g; double d;} d;
memcpy(&d, buf + offset, 8);
d.g = GUINT64_FROM_LE(d.g);
return d.d;
}
double mdb_pg_get_double(MdbHandle *mdb, int offset)
{
if (offset <0 || offset+8 > mdb->fmt->pg_size) return -1;
mdb->cur_pos+=8;
return mdb_get_double(mdb->pg_buf, offset);
}
int
mdb_set_pos(MdbHandle *mdb, int pos)
{
if (pos<0 || pos >= mdb->fmt->pg_size) return 0;
mdb->cur_pos=pos;
return pos;
}
int mdb_get_pos(MdbHandle *mdb)
{
return mdb->cur_pos;
}