tdbutil.c

samba-3.0.22.tar.gz 编译smb服务器的源码

/* 
   Unix SMB/CIFS implementation.
   tdb utility functions
   Copyright (C) Andrew Tridgell   1992-1998
   Copyright (C) Rafal Szczesniak  2002
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"
#include <fnmatch.h>

/* these are little tdb utility functions that are meant to make
   dealing with a tdb database a little less cumbersome in Samba */

static SIG_ATOMIC_T gotalarm;

/***************************************************************
 Signal function to tell us we timed out.
****************************************************************/

static void gotalarm_sig(void)
{
	gotalarm = 1;
}

/***************************************************************
 Make a TDB_DATA and keep the const warning in one place
****************************************************************/

TDB_DATA make_tdb_data(const char *dptr, size_t dsize)
{
	TDB_DATA ret;
	ret.dptr = CONST_DISCARD(char *, dptr);
	ret.dsize = dsize;
	return ret;
}

TDB_DATA string_tdb_data(const char *string)
{
	return make_tdb_data(string, strlen(string));
}

/****************************************************************************
 Lock a chain with timeout (in seconds).
****************************************************************************/

static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
{
	/* Allow tdb_chainlock to be interrupted by an alarm. */
	int ret;
	gotalarm = 0;
	tdb_set_lock_alarm(CONST_DISCARD(sig_atomic_t *, &gotalarm));

	if (timeout) {
		CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
		alarm(timeout);
	}

	if (rw_type == F_RDLCK)
		ret = tdb_chainlock_read(tdb, key);
	else
		ret = tdb_chainlock(tdb, key);

	if (timeout) {
		alarm(0);
		CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
		if (gotalarm) {
			DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",
				timeout, key.dptr, tdb->name ));
			/* TODO: If we time out waiting for a lock, it might
			 * be nice to use F_GETLK to get the pid of the
			 * process currently holding the lock and print that
			 * as part of the debugging message. -- mbp */
			return -1;
		}
	}

	return ret;
}

/****************************************************************************
 Write lock a chain. Return -1 if timeout or lock failed.
****************************************************************************/

int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout)
{
	return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
}

/****************************************************************************
 Lock a chain by string. Return -1 if timeout or lock failed.
****************************************************************************/

int tdb_lock_bystring(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout)
{
	TDB_DATA key = make_tdb_data(keyval, strlen(keyval)+1);
	
	return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
}

/****************************************************************************
 Unlock a chain by string.
****************************************************************************/

void tdb_unlock_bystring(TDB_CONTEXT *tdb, const char *keyval)
{
	TDB_DATA key = make_tdb_data(keyval, strlen(keyval)+1);

	tdb_chainunlock(tdb, key);
}

/****************************************************************************
 Read lock a chain by string. Return -1 if timeout or lock failed.
****************************************************************************/

int tdb_read_lock_bystring(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout)
{
	TDB_DATA key = make_tdb_data(keyval, strlen(keyval)+1);
	
	return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_RDLCK);
}

/****************************************************************************
 Read unlock a chain by string.
****************************************************************************/

void tdb_read_unlock_bystring(TDB_CONTEXT *tdb, const char *keyval)
{
	TDB_DATA key = make_tdb_data(keyval, strlen(keyval)+1);
	
	tdb_chainunlock_read(tdb, key);
}


/****************************************************************************
 Fetch a int32 value by a arbitrary blob key, return -1 if not found.
 Output is int32 in native byte order.
****************************************************************************/

int32 tdb_fetch_int32_byblob(TDB_CONTEXT *tdb, const char *keyval, size_t len)
{
	TDB_DATA key = make_tdb_data(keyval, len);
	TDB_DATA data;
	int32 ret;

	data = tdb_fetch(tdb, key);
	if (!data.dptr || data.dsize != sizeof(int32)) {
		SAFE_FREE(data.dptr);
		return -1;
	}

	ret = IVAL(data.dptr,0);
	SAFE_FREE(data.dptr);
	return ret;
}

/****************************************************************************
 Fetch a int32 value by string key, return -1 if not found.
 Output is int32 in native byte order.
****************************************************************************/

int32 tdb_fetch_int32(TDB_CONTEXT *tdb, const char *keystr)
{
	return tdb_fetch_int32_byblob(tdb, keystr, strlen(keystr) + 1);
}

/****************************************************************************
 Store a int32 value by an arbitary blob key, return 0 on success, -1 on failure.
 Input is int32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

int tdb_store_int32_byblob(TDB_CONTEXT *tdb, const char *keystr, size_t len, int32 v)
{
	TDB_DATA key = make_tdb_data(keystr, len);
	TDB_DATA data;
	int32 v_store;

	SIVAL(&v_store,0,v);
	data.dptr = (void *)&v_store;
	data.dsize = sizeof(int32);

	return tdb_store(tdb, key, data, TDB_REPLACE);
}

/****************************************************************************
 Store a int32 value by string key, return 0 on success, -1 on failure.
 Input is int32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

int tdb_store_int32(TDB_CONTEXT *tdb, const char *keystr, int32 v)
{
	return tdb_store_int32_byblob(tdb, keystr, strlen(keystr) + 1, v);
}

/****************************************************************************
 Fetch a uint32 value by a arbitrary blob key, return -1 if not found.
 Output is uint32 in native byte order.
****************************************************************************/

BOOL tdb_fetch_uint32_byblob(TDB_CONTEXT *tdb, const char *keyval, size_t len, uint32 *value)
{
	TDB_DATA key = make_tdb_data(keyval, len);
	TDB_DATA data;

	data = tdb_fetch(tdb, key);
	if (!data.dptr || data.dsize != sizeof(uint32)) {
		SAFE_FREE(data.dptr);
		return False;
	}

	*value = IVAL(data.dptr,0);
	SAFE_FREE(data.dptr);
	return True;
}

/****************************************************************************
 Fetch a uint32 value by string key, return -1 if not found.
 Output is uint32 in native byte order.
****************************************************************************/

BOOL tdb_fetch_uint32(TDB_CONTEXT *tdb, const char *keystr, uint32 *value)
{
	return tdb_fetch_uint32_byblob(tdb, keystr, strlen(keystr) + 1, value);
}

/****************************************************************************
 Store a uint32 value by an arbitary blob key, return 0 on success, -1 on failure.
 Input is uint32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

BOOL tdb_store_uint32_byblob(TDB_CONTEXT *tdb, const char *keystr, size_t len, uint32 value)
{
	TDB_DATA key = make_tdb_data(keystr, len);
	TDB_DATA data;
	uint32 v_store;
	BOOL ret = True;

	SIVAL(&v_store, 0, value);
	data.dptr = (void *)&v_store;
	data.dsize = sizeof(uint32);

	if (tdb_store(tdb, key, data, TDB_REPLACE) == -1)
		ret = False;

	return ret;
}

/****************************************************************************
 Store a uint32 value by string key, return 0 on success, -1 on failure.
 Input is uint32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

BOOL tdb_store_uint32(TDB_CONTEXT *tdb, const char *keystr, uint32 value)
{
	return tdb_store_uint32_byblob(tdb, keystr, strlen(keystr) + 1, value);
}
/****************************************************************************
 Store a buffer by a null terminated string key.  Return 0 on success, -1
 on failure.
****************************************************************************/

int tdb_store_bystring(TDB_CONTEXT *tdb, const char *keystr, TDB_DATA data, int flags)
{
	TDB_DATA key = make_tdb_data(keystr, strlen(keystr)+1);
	
	return tdb_store(tdb, key, data, flags);
}

/****************************************************************************
 Fetch a buffer using a null terminated string key.  Don't forget to call
 free() on the result dptr.
****************************************************************************/

TDB_DATA tdb_fetch_bystring(TDB_CONTEXT *tdb, const char *keystr)
{
	TDB_DATA key = make_tdb_data(keystr, strlen(keystr)+1);

	return tdb_fetch(tdb, key);
}

/****************************************************************************
 Delete an entry using a null terminated string key. 
****************************************************************************/

int tdb_delete_bystring(TDB_CONTEXT *tdb, const char *keystr)
{
	TDB_DATA key = make_tdb_data(keystr, strlen(keystr)+1);

	return tdb_delete(tdb, key);
}

/****************************************************************************
 Atomic integer change. Returns old value. To create, set initial value in *oldval. 
****************************************************************************/

int32 tdb_change_int32_atomic(TDB_CONTEXT *tdb, const char *keystr, int32 *oldval, int32 change_val)
{
	int32 val;
	int32 ret = -1;

	if (tdb_lock_bystring(tdb, keystr,0) == -1)
		return -1;

	if ((val = tdb_fetch_int32(tdb, keystr)) == -1) {
		/* The lookup failed */
		if (tdb_error(tdb) != TDB_ERR_NOEXIST) {
			/* but not because it didn't exist */
			goto err_out;
		}
		
		/* Start with 'old' value */
		val = *oldval;

	} else {
		/* It worked, set return value (oldval) to tdb data */
		*oldval = val;
	}

	/* Increment value for storage and return next time */
	val += change_val;
		
	if (tdb_store_int32(tdb, keystr, val) == -1)
		goto err_out;

	ret = 0;

  err_out:

	tdb_unlock_bystring(tdb, keystr);
	return ret;
}

/****************************************************************************
 Atomic unsigned integer change. Returns old value. To create, set initial value in *oldval. 
****************************************************************************/

BOOL tdb_change_uint32_atomic(TDB_CONTEXT *tdb, const char *keystr, uint32 *oldval, uint32 change_val)
{
	uint32 val;
	BOOL ret = False;

	if (tdb_lock_bystring(tdb, keystr,0) == -1)
		return False;

	if (!tdb_fetch_uint32(tdb, keystr, &val)) {
		/* It failed */
		if (tdb_error(tdb) != TDB_ERR_NOEXIST) { 
			/* and not because it didn't exist */
			goto err_out;
		}

		/* Start with 'old' value */
		val = *oldval;

	} else {
		/* it worked, set return value (oldval) to tdb data */
		*oldval = val;

	}

	/* get a new value to store */
	val += change_val;
		
	if (!tdb_store_uint32(tdb, keystr, val))
		goto err_out;

	ret = True;

  err_out:

	tdb_unlock_bystring(tdb, keystr);
	return ret;
}

/****************************************************************************
 Useful pair of routines for packing/unpacking data consisting of
 integers and strings.
****************************************************************************/

size_t tdb_pack_va(char *buf, int bufsize, const char *fmt, va_list ap)
{
	uint8 bt;
	uint16 w;
	uint32 d;
	int i;
	void *p;
	int len;
	char *s;
	char c;
	char *buf0 = buf;
	const char *fmt0 = fmt;
	int bufsize0 = bufsize;

	while (*fmt) {
		switch ((c = *fmt++)) {
		case 'b': /* unsigned 8-bit integer */
			len = 1;
			bt = (uint8)va_arg(ap, int);
			if (bufsize && bufsize >= len)
				SSVAL(buf, 0, bt);
			break;
		case 'w': /* unsigned 16-bit integer */
			len = 2;
			w = (uint16)va_arg(ap, int);
			if (bufsize && bufsize >= len)
				SSVAL(buf, 0, w);
			break;
		case 'd': /* signed 32-bit integer (standard int in most systems) */
			len = 4;
			d = va_arg(ap, uint32);
			if (bufsize && bufsize >= len)
				SIVAL(buf, 0, d);
			break;
		case 'p': /* pointer */
			len = 4;
			p = va_arg(ap, void *);
			d = p?1:0;
			if (bufsize && bufsize >= len)
				SIVAL(buf, 0, d);
			break;
		case 'P': /* null-terminated string */
			s = va_arg(ap,char *);
			w = strlen(s);
			len = w + 1;
			if (bufsize && bufsize >= len)
				memcpy(buf, s, len);