parse_prs.c

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/* 
   Unix SMB/CIFS implementation.
   Samba memory buffer functions
   Copyright (C) Andrew Tridgell              1992-1997
   Copyright (C) Luke Kenneth Casson Leighton 1996-1997
   Copyright (C) Jeremy Allison               1999
   Copyright (C) Andrew Bartlett              2003.
   
   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"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_RPC_PARSE

/**
 * Dump a prs to a file: from the current location through to the end.
 **/
void prs_dump(char *name, int v, prs_struct *ps)
{
	prs_dump_region(name, v, ps, ps->data_offset, ps->buffer_size);
}

/**
 * Dump from the start of the prs to the current location.
 **/
void prs_dump_before(char *name, int v, prs_struct *ps)
{
	prs_dump_region(name, v, ps, 0, ps->data_offset);
}

/**
 * Dump everything from the start of the prs up to the current location.
 **/
void prs_dump_region(char *name, int v, prs_struct *ps,
		     int from_off, int to_off)
{
	int fd, i;
	pstring fname;
	ssize_t sz;
	if (DEBUGLEVEL < 50) return;
	for (i=1;i<100;i++) {
		if (v != -1) {
			slprintf(fname,sizeof(fname)-1, "/tmp/%s_%d.%d.prs", name, v, i);
		} else {
			slprintf(fname,sizeof(fname)-1, "/tmp/%s.%d.prs", name, i);
		}
		fd = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0644);
		if (fd != -1 || errno != EEXIST) break;
	}
	if (fd != -1) {
		sz = write(fd, ps->data_p + from_off, to_off - from_off);
		i = close(fd);
		if ( (sz != to_off-from_off) || (i != 0) ) {
			DEBUG(0,("Error writing/closing %s: %ld!=%ld %d\n", fname, (unsigned long)sz, (unsigned long)to_off-from_off, i ));
		} else {
			DEBUG(0,("created %s\n", fname));
		}
	}
}

/*******************************************************************
 Debug output for parsing info

 XXXX side-effect of this function is to increase the debug depth XXXX.

********************************************************************/

void prs_debug(prs_struct *ps, int depth, const char *desc, const char *fn_name)
{
	DEBUG(5+depth, ("%s%06x %s %s\n", tab_depth(depth), ps->data_offset, fn_name, desc));
}

/**
 * Initialise an expandable parse structure.
 *
 * @param size Initial buffer size.  If >0, a new buffer will be
 * created with malloc().
 *
 * @return False if allocation fails, otherwise True.
 **/

BOOL prs_init(prs_struct *ps, uint32 size, TALLOC_CTX *ctx, BOOL io)
{
	ZERO_STRUCTP(ps);
	ps->io = io;
	ps->bigendian_data = RPC_LITTLE_ENDIAN;
	ps->align = RPC_PARSE_ALIGN;
	ps->is_dynamic = False;
	ps->data_offset = 0;
	ps->buffer_size = 0;
	ps->data_p = NULL;
	ps->mem_ctx = ctx;

	if (size != 0) {
		ps->buffer_size = size;
		if((ps->data_p = (char *)SMB_MALLOC((size_t)size)) == NULL) {
			DEBUG(0,("prs_init: malloc fail for %u bytes.\n", (unsigned int)size));
			return False;
		}
		memset(ps->data_p, '\0', (size_t)size);
		ps->is_dynamic = True; /* We own this memory. */
	} else if (MARSHALLING(ps)) {
		/* If size is zero and we're marshalling we should allocate memory on demand. */
		ps->is_dynamic = True;
	}

	return True;
}

/*******************************************************************
 Delete the memory in a parse structure - if we own it.
 ********************************************************************/

void prs_mem_free(prs_struct *ps)
{
	if(ps->is_dynamic)
		SAFE_FREE(ps->data_p);
	ps->is_dynamic = False;
	ps->buffer_size = 0;
	ps->data_offset = 0;
}

/*******************************************************************
 Clear the memory in a parse structure.
 ********************************************************************/

void prs_mem_clear(prs_struct *ps)
{
	if (ps->buffer_size)
		memset(ps->data_p, '\0', (size_t)ps->buffer_size);
}

/*******************************************************************
 Allocate memory when unmarshalling... Always zero clears.
 ********************************************************************/

#if defined(PARANOID_MALLOC_CHECKER)
char *prs_alloc_mem_(prs_struct *ps, size_t size, unsigned int count)
#else
char *prs_alloc_mem(prs_struct *ps, size_t size, unsigned int count)
#endif
{
	char *ret = NULL;

	if (size) {
		/* We can't call the type-safe version here. */
		ret = _talloc_zero_array(ps->mem_ctx, size, count, "parse_prs");
	}
	return ret;
}

/*******************************************************************
 Return the current talloc context we're using.
 ********************************************************************/

TALLOC_CTX *prs_get_mem_context(prs_struct *ps)
{
	return ps->mem_ctx;
}

/*******************************************************************
 Hand some already allocated memory to a prs_struct.
 ********************************************************************/

void prs_give_memory(prs_struct *ps, char *buf, uint32 size, BOOL is_dynamic)
{
	ps->is_dynamic = is_dynamic;
	ps->data_p = buf;
	ps->buffer_size = size;
}

/*******************************************************************
 Take some memory back from a prs_struct.
 ********************************************************************/

char *prs_take_memory(prs_struct *ps, uint32 *psize)
{
	char *ret = ps->data_p;
	if(psize)
		*psize = ps->buffer_size;
	ps->is_dynamic = False;
	prs_mem_free(ps);
	return ret;
}

/*******************************************************************
 Set a prs_struct to exactly a given size. Will grow or tuncate if neccessary.
 ********************************************************************/

BOOL prs_set_buffer_size(prs_struct *ps, uint32 newsize)
{
	if (newsize > ps->buffer_size)
		return prs_force_grow(ps, newsize - ps->buffer_size);

	if (newsize < ps->buffer_size) {
		char *new_data_p = SMB_REALLOC(ps->data_p, newsize);
		/* if newsize is zero, Realloc acts like free() & returns NULL*/
		if (new_data_p == NULL && newsize != 0) {
			DEBUG(0,("prs_set_buffer_size: Realloc failure for size %u.\n",
				(unsigned int)newsize));
			DEBUG(0,("prs_set_buffer_size: Reason %s\n",strerror(errno)));
			return False;
		}
		ps->data_p = new_data_p;
		ps->buffer_size = newsize;
	}

	return True;
}

/*******************************************************************
 Attempt, if needed, to grow a data buffer.
 Also depends on the data stream mode (io).
 ********************************************************************/

BOOL prs_grow(prs_struct *ps, uint32 extra_space)
{
	uint32 new_size;
	char *new_data;

	ps->grow_size = MAX(ps->grow_size, ps->data_offset + extra_space);

	if(ps->data_offset + extra_space <= ps->buffer_size)
		return True;

	/*
	 * We cannot grow the buffer if we're not reading
	 * into the prs_struct, or if we don't own the memory.
	 */

	if(UNMARSHALLING(ps) || !ps->is_dynamic) {
		DEBUG(0,("prs_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
				(unsigned int)extra_space));
		return False;
	}
	
	/*
	 * Decide how much extra space we really need.
	 */

	extra_space -= (ps->buffer_size - ps->data_offset);
	if(ps->buffer_size == 0) {
		/*
		 * Ensure we have at least a PDU's length, or extra_space, whichever
		 * is greater.
		 */

		new_size = MAX(RPC_MAX_PDU_FRAG_LEN,extra_space);

		if((new_data = SMB_MALLOC(new_size)) == NULL) {
			DEBUG(0,("prs_grow: Malloc failure for size %u.\n", (unsigned int)new_size));
			return False;
		}
		memset(new_data, '\0', (size_t)new_size );
	} else {
		/*
		 * If the current buffer size is bigger than the space needed, just 
		 * double it, else add extra_space.
		 */
		new_size = MAX(ps->buffer_size*2, ps->buffer_size + extra_space);		

		if ((new_data = SMB_REALLOC(ps->data_p, new_size)) == NULL) {
			DEBUG(0,("prs_grow: Realloc failure for size %u.\n",
				(unsigned int)new_size));
			return False;
		}

		memset(&new_data[ps->buffer_size], '\0', (size_t)(new_size - ps->buffer_size));
	}
	ps->buffer_size = new_size;
	ps->data_p = new_data;

	return True;
}

/*******************************************************************
 Attempt to force a data buffer to grow by len bytes.
 This is only used when appending more data onto a prs_struct
 when reading an rpc reply, before unmarshalling it.
 ********************************************************************/

BOOL prs_force_grow(prs_struct *ps, uint32 extra_space)
{
	uint32 new_size = ps->buffer_size + extra_space;
	char *new_data;

	if(!UNMARSHALLING(ps) || !ps->is_dynamic) {
		DEBUG(0,("prs_force_grow: Buffer overflow - unable to expand buffer by %u bytes.\n",
				(unsigned int)extra_space));
		return False;
	}

	if((new_data = SMB_REALLOC(ps->data_p, new_size)) == NULL) {
		DEBUG(0,("prs_force_grow: Realloc failure for size %u.\n",
			(unsigned int)new_size));
		return False;
	}

	memset(&new_data[ps->buffer_size], '\0', (size_t)(new_size - ps->buffer_size));

	ps->buffer_size = new_size;
	ps->data_p = new_data;

	return True;
}

/*******************************************************************
 Get the data pointer (external interface).
********************************************************************/

char *prs_data_p(prs_struct *ps)
{
	return ps->data_p;
}

/*******************************************************************
 Get the current data size (external interface).
 ********************************************************************/

uint32 prs_data_size(prs_struct *ps)
{
	return ps->buffer_size;
}

/*******************************************************************
 Fetch the current offset (external interface).
 ********************************************************************/

uint32 prs_offset(prs_struct *ps)
{
	return ps->data_offset;
}

/*******************************************************************
 Set the current offset (external interface).
 ********************************************************************/

BOOL prs_set_offset(prs_struct *ps, uint32 offset)
{
	if(offset <= ps->data_offset) {
		ps->data_offset = offset;
		return True;
	}

	if(!prs_grow(ps, offset - ps->data_offset))
		return False;

	ps->data_offset = offset;
	return True;
}

/*******************************************************************
 Append the data from one parse_struct into another.
 ********************************************************************/

BOOL prs_append_prs_data(prs_struct *dst, prs_struct *src)
{
	if (prs_offset(src) == 0)
		return True;

	if(!prs_grow(dst, prs_offset(src)))
		return False;

	memcpy(&dst->data_p[dst->data_offset], src->data_p, (size_t)prs_offset(src));
	dst->data_offset += prs_offset(src);

	return True;
}

/*******************************************************************
 Append some data from one parse_struct into another.
 ********************************************************************/

BOOL prs_append_some_prs_data(prs_struct *dst, prs_struct *src, int32 start, uint32 len)
{	
	if (len == 0)
		return True;

	if(!prs_grow(dst, len))
		return False;
	
	memcpy(&dst->data_p[dst->data_offset], src->data_p + start, (size_t)len);
	dst->data_offset += len;

	return True;
}

/*******************************************************************
 Append the data from a buffer into a parse_struct.
 ********************************************************************/

BOOL prs_copy_data_in(prs_struct *dst, const char *src, uint32 len)
{
	if (len == 0)
		return True;

	if(!prs_grow(dst, len))
		return False;

	memcpy(&dst->data_p[dst->data_offset], src, (size_t)len);
	dst->data_offset += len;

	return True;
}

/*******************************************************************
 Copy some data from a parse_struct into a buffer.
 ********************************************************************/

BOOL prs_copy_data_out(char *dst, prs_struct *src, uint32 len)
{
	if (len == 0)
		return True;

	if(!prs_mem_get(src, len))
		return False;

	memcpy(dst, &src->data_p[src->data_offset], (size_t)len);
	src->data_offset += len;