src/buffer.c - haproxy - Gitiles

 /*
  * Buffer management functions.
  *
  * Copyright 2000-2012 Willy Tarreau <w@1wt.eu>
  *
  * 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.
  *
  */

 #include <ctype.h>
 #include <stdio.h>
 #include <string.h>

 #include <common/config.h>
 #include <common/buffer.h>
 #include <common/memory.h>

 #include <types/global.h>

 struct pool_head *pool2_buffer;

 /* These buffers are used to always have a valid pointer to an empty buffer in
  * channels. The first buffer is set once a buffer is empty. The second one is
  * set when a buffer is desired but no more are available. It helps knowing
  * what channel wants a buffer. They can reliably be exchanged, the split
  * between the two is only an optimization.
  */
 struct buffer buf_empty  = { .p = buf_empty.data };
 struct buffer buf_wanted = { .p = buf_wanted.data };

 /* list of objects waiting for at least one buffer */
 struct list buffer_wq = LIST_HEAD_INIT(buffer_wq);

 /* this buffer is always the same size as standard buffers and is used for
  * swapping data inside a buffer.
  */
 static char *swap_buffer = NULL;

 /* perform minimal intializations, report 0 in case of error, 1 if OK. */
 int init_buffer()
 {
 	void *buffer;

 	pool2_buffer = create_pool("buffer", sizeof (struct buffer) + global.tune.bufsize, MEM_F_SHARED|MEM_F_EXACT);
 	if (!pool2_buffer)
 		return 0;

 	/* The reserved buffer is what we leave behind us. Thus we always need
 	 * at least one extra buffer in minavail otherwise we'll end up waking
 	 * up tasks with no memory available, causing a lot of useless wakeups.
 	 * That means that we always want to have at least 3 buffers available
 	 * (2 for current session, one for next session that might be needed to
 	 * release a server connection).
 	 */
 	pool2_buffer->minavail = MAX(global.tune.reserved_bufs, 3);
 	if (global.tune.buf_limit)
 		pool2_buffer->limit = global.tune.buf_limit;

 	buffer = pool_refill_alloc(pool2_buffer, pool2_buffer->minavail - 1);
 	if (!buffer)
 		return 0;

 	pool_free2(pool2_buffer, buffer);

 	swap_buffer = calloc(1, global.tune.bufsize);
 	if (swap_buffer == NULL)
 		return 0;

 	return 1;
 }

 void deinit_buffer()
 {
 	free(swap_buffer); swap_buffer = NULL;
 	pool_destroy2(pool2_buffer);
 }

 /* This function writes the string <str> at position <pos> which must be in
  * buffer <b>, and moves <end> just after the end of <str>. <b>'s parameters
  * <l> and <r> are updated to be valid after the shift. The shift value
  * (positive or negative) is returned. If there's no space left, the move is
  * not done. The function does not adjust ->o because it does not make sense to
  * use it on data scheduled to be sent. For the same reason, it does not make
  * sense to call this function on unparsed data, so <orig> is not updated. The
  * string length is taken from parameter <len>. If <len> is null, the <str>
  * pointer is allowed to be null.
  */
 int buffer_replace2(struct buffer *b, char *pos, char *end, const char *str, int len)
 {
 	int delta;

 	delta = len - (end - pos);

 	if (bi_end(b) + delta > b->data + b->size)
 		return 0;  /* no space left */

 	if (buffer_not_empty(b) &&
 	    bi_end(b) + delta > bo_ptr(b) &&
 	    bo_ptr(b) >= bi_end(b))
 		return 0;  /* no space left before wrapping data */

 	/* first, protect the end of the buffer */
 	memmove(end + delta, end, bi_end(b) - end);

 	/* now, copy str over pos */
 	if (len)
 		memcpy(pos, str, len);

 	b->i += delta;

 	if (buffer_empty(b))
 		b->p = b->data;

 	return delta;
 }

 /*
  * Inserts <str> followed by "\r\n" at position <pos> in buffer <b>. The <len>
  * argument informs about the length of string <str> so that we don't have to
  * measure it. It does not include the "\r\n". If <str> is NULL, then the buffer
  * is only opened for len+2 bytes but nothing is copied in. It may be useful in
  * some circumstances. The send limit is *not* adjusted. Same comments as above
  * for the valid use cases.
  *
  * The number of bytes added is returned on success. 0 is returned on failure.
  */
 int buffer_insert_line2(struct buffer *b, char *pos, const char *str, int len)
 {
 	int delta;

 	delta = len + 2;

 	if (bi_end(b) + delta >= b->data + b->size)
 		return 0;  /* no space left */

 	if (buffer_not_empty(b) &&
 	    bi_end(b) + delta > bo_ptr(b) &&
 	    bo_ptr(b) >= bi_end(b))
 		return 0;  /* no space left before wrapping data */

 	/* first, protect the end of the buffer */
 	memmove(pos + delta, pos, bi_end(b) - pos);

 	/* now, copy str over pos */
 	if (len && str) {
 		memcpy(pos, str, len);
 		pos[len] = '\r';
 		pos[len + 1] = '\n';
 	}

 	b->i += delta;
 	return delta;
 }

 /* This function realigns a possibly wrapping buffer so that the input part is
  * contiguous and starts at the beginning of the buffer and the output part
  * ends at the end of the buffer. This provides the best conditions since it
  * allows the largest inputs to be processed at once and ensures that once the
  * output data leaves, the whole buffer is available at once.
  */
 void buffer_slow_realign(struct buffer *buf)
 {
 	int block1 = buf->o;
 	int block2 = 0;

 	/* process output data in two steps to cover wrapping */
 	if (block1 > buf->p - buf->data) {
 		block2 = buf->p - buf->data;
 		block1 -= block2;
 	}
 	memcpy(swap_buffer + buf->size - buf->o, bo_ptr(buf), block1);
 	memcpy(swap_buffer + buf->size - block2, buf->data, block2);

 	/* process input data in two steps to cover wrapping */
 	block1 = buf->i;
 	block2 = 0;

 	if (block1 > buf->data + buf->size - buf->p) {
 		block1 = buf->data + buf->size - buf->p;
 		block2 = buf->i - block1;
 	}
 	memcpy(swap_buffer, bi_ptr(buf), block1);
 	memcpy(swap_buffer + block1, buf->data, block2);

 	/* reinject changes into the buffer */
 	memcpy(buf->data, swap_buffer, buf->i);
 	memcpy(buf->data + buf->size - buf->o, swap_buffer + buf->size - buf->o, buf->o);

 	buf->p = buf->data;
 }

 /*
  * Dumps part or all of a buffer.
  */
 void buffer_dump(FILE *o, struct buffer *b, int from, int to)
 {
 	fprintf(o, "Dumping buffer %p\n", b);
 	fprintf(o, "            data=%p o=%d i=%d p=%p\n"
                    "            relative:   p=0x%04x\n",
 		b->data, b->o, b->i, b->p, (unsigned int)(b->p - b->data));

 	fprintf(o, "Dumping contents from byte %d to byte %d\n", from, to);
 	fprintf(o, "         0  1  2  3  4  5  6  7    8  9  a  b  c  d  e  f\n");
 	/* dump hexa */
 	while (from < to) {
 		int i;

 		fprintf(o, "  %04x: ", from);
 		for (i = 0; ((from + i) < to) && (i < 16) ; i++) {
 			fprintf(o, "%02x ", (unsigned char)b->data[from + i]);
 			if (((from + i)  & 15) == 7)
 				fprintf(o, "- ");
 		}
 		if (to - from < 16) {
 			int j = 0;

 			for (j = 0; j <  from + 16 - to; j++)
 				fprintf(o, "   ");
 			if (j > 8)
 				fprintf(o, "  ");
 		}
 		fprintf(o, "  ");
 		for (i = 0; (from + i < to) && (i < 16) ; i++) {
 			fprintf(o, "%c", isprint((int)b->data[from + i]) ? b->data[from + i] : '.') ;
 			if ((((from + i) & 15) == 15) && ((from + i) != to-1))
 				fprintf(o, "\n");
 		}
 		from += i;
 	}
 	fprintf(o, "\n--\n");
 	fflush(o);
 }

 void __offer_buffer(void *from, unsigned int threshold)
 {
 	struct buffer_wait *wait, *bak;
 	int avail;

 	/* For now, we consider that all objects need 1 buffer, so we can stop
 	 * waking up them once we have enough of them to eat all the available
 	 * buffers. Note that we don't really know if they are streams or just
 	 * other tasks, but that's a rough estimate. Similarly, for each cached
 	 * event we'll need 1 buffer. If no buffer is currently used, always
 	 * wake up the number of tasks we can offer a buffer based on what is
 	 * allocated, and in any case at least one task per two reserved
 	 * buffers.
 	 */
 	avail = pool2_buffer->allocated - pool2_buffer->used - global.tune.reserved_bufs / 2;

 	list_for_each_entry_safe(wait, bak, &buffer_wq, list) {
 		if (avail <= threshold)
 			break;

 		if (wait->target == from || !wait->wakeup_cb(wait->target))
 			continue;

 		LIST_DEL(&wait->list);
 		LIST_INIT(&wait->list);

 		avail--;
 	}
 }

 /*
  * Local variables:
  *  c-indent-level: 8
  *  c-basic-offset: 8
  * End:
  */
	/*
	* Buffer management functions.
	*
	* Copyright 2000-2012 Willy Tarreau <w@1wt.eu>
	*
	* 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.
	*
	*/

	#include <ctype.h>
	#include <stdio.h>
	#include <string.h>

	#include <common/config.h>
	#include <common/buffer.h>
	#include <common/memory.h>

	#include <types/global.h>

	struct pool_head *pool2_buffer;

	/* These buffers are used to always have a valid pointer to an empty buffer in
	* channels. The first buffer is set once a buffer is empty. The second one is
	* set when a buffer is desired but no more are available. It helps knowing
	* what channel wants a buffer. They can reliably be exchanged, the split
	* between the two is only an optimization.
	*/
	struct buffer buf_empty = { .p = buf_empty.data };
	struct buffer buf_wanted = { .p = buf_wanted.data };

	/* list of objects waiting for at least one buffer */
	struct list buffer_wq = LIST_HEAD_INIT(buffer_wq);

	/* this buffer is always the same size as standard buffers and is used for
	* swapping data inside a buffer.
	*/
	static char *swap_buffer = NULL;

	/* perform minimal intializations, report 0 in case of error, 1 if OK. */
	int init_buffer()
	{
	void *buffer;

	pool2_buffer = create_pool("buffer", sizeof (struct buffer) + global.tune.bufsize, MEM_F_SHARED\|MEM_F_EXACT);
	if (!pool2_buffer)
	return 0;

	/* The reserved buffer is what we leave behind us. Thus we always need
	* at least one extra buffer in minavail otherwise we'll end up waking
	* up tasks with no memory available, causing a lot of useless wakeups.
	* That means that we always want to have at least 3 buffers available
	* (2 for current session, one for next session that might be needed to
	* release a server connection).
	*/
	pool2_buffer->minavail = MAX(global.tune.reserved_bufs, 3);
	if (global.tune.buf_limit)
	pool2_buffer->limit = global.tune.buf_limit;

	buffer = pool_refill_alloc(pool2_buffer, pool2_buffer->minavail - 1);
	if (!buffer)
	return 0;

	pool_free2(pool2_buffer, buffer);

	swap_buffer = calloc(1, global.tune.bufsize);
	if (swap_buffer == NULL)
	return 0;

	return 1;
	}

	void deinit_buffer()
	{
	free(swap_buffer); swap_buffer = NULL;
	pool_destroy2(pool2_buffer);
	}

	/* This function writes the string <str> at position <pos> which must be in
	* buffer <b>, and moves <end> just after the end of <str>. <b>'s parameters
	* <l> and <r> are updated to be valid after the shift. The shift value
	* (positive or negative) is returned. If there's no space left, the move is
	* not done. The function does not adjust ->o because it does not make sense to
	* use it on data scheduled to be sent. For the same reason, it does not make
	* sense to call this function on unparsed data, so <orig> is not updated. The
	* string length is taken from parameter <len>. If <len> is null, the <str>
	* pointer is allowed to be null.
	*/
	int buffer_replace2(struct buffer b, char pos, char end, const char str, int len)
	{
	int delta;

	delta = len - (end - pos);

	if (bi_end(b) + delta > b->data + b->size)
	return 0; /* no space left */

	if (buffer_not_empty(b) &&
	bi_end(b) + delta > bo_ptr(b) &&
	bo_ptr(b) >= bi_end(b))
	return 0; /* no space left before wrapping data */

	/* first, protect the end of the buffer */
	memmove(end + delta, end, bi_end(b) - end);

	/* now, copy str over pos */
	if (len)
	memcpy(pos, str, len);

	b->i += delta;

	if (buffer_empty(b))
	b->p = b->data;

	return delta;
	}

	/*
	* Inserts <str> followed by "\r\n" at position <pos> in buffer <b>. The <len>
	* argument informs about the length of string <str> so that we don't have to
	* measure it. It does not include the "\r\n". If <str> is NULL, then the buffer
	* is only opened for len+2 bytes but nothing is copied in. It may be useful in
	* some circumstances. The send limit is not adjusted. Same comments as above
	* for the valid use cases.
	*
	* The number of bytes added is returned on success. 0 is returned on failure.
	*/
	int buffer_insert_line2(struct buffer b, char pos, const char *str, int len)
	{
	int delta;

	delta = len + 2;

	if (bi_end(b) + delta >= b->data + b->size)
	return 0; /* no space left */

	if (buffer_not_empty(b) &&
	bi_end(b) + delta > bo_ptr(b) &&
	bo_ptr(b) >= bi_end(b))
	return 0; /* no space left before wrapping data */

	/* first, protect the end of the buffer */
	memmove(pos + delta, pos, bi_end(b) - pos);

	/* now, copy str over pos */
	if (len && str) {
	memcpy(pos, str, len);
	pos[len] = '\r';
	pos[len + 1] = '\n';
	}

	b->i += delta;
	return delta;
	}

	/* This function realigns a possibly wrapping buffer so that the input part is
	* contiguous and starts at the beginning of the buffer and the output part
	* ends at the end of the buffer. This provides the best conditions since it
	* allows the largest inputs to be processed at once and ensures that once the
	* output data leaves, the whole buffer is available at once.
	*/
	void buffer_slow_realign(struct buffer *buf)
	{
	int block1 = buf->o;
	int block2 = 0;

	/* process output data in two steps to cover wrapping */
	if (block1 > buf->p - buf->data) {
	block2 = buf->p - buf->data;
	block1 -= block2;
	}
	memcpy(swap_buffer + buf->size - buf->o, bo_ptr(buf), block1);
	memcpy(swap_buffer + buf->size - block2, buf->data, block2);

	/* process input data in two steps to cover wrapping */
	block1 = buf->i;
	block2 = 0;

	if (block1 > buf->data + buf->size - buf->p) {
	block1 = buf->data + buf->size - buf->p;
	block2 = buf->i - block1;
	}
	memcpy(swap_buffer, bi_ptr(buf), block1);
	memcpy(swap_buffer + block1, buf->data, block2);

	/* reinject changes into the buffer */
	memcpy(buf->data, swap_buffer, buf->i);
	memcpy(buf->data + buf->size - buf->o, swap_buffer + buf->size - buf->o, buf->o);

	buf->p = buf->data;
	}

	/*
	* Dumps part or all of a buffer.
	*/
	void buffer_dump(FILE o, struct buffer b, int from, int to)
	{
	fprintf(o, "Dumping buffer %p\n", b);
	fprintf(o, " data=%p o=%d i=%d p=%p\n"
	" relative: p=0x%04x\n",
	b->data, b->o, b->i, b->p, (unsigned int)(b->p - b->data));

	fprintf(o, "Dumping contents from byte %d to byte %d\n", from, to);
	fprintf(o, " 0 1 2 3 4 5 6 7 8 9 a b c d e f\n");
	/* dump hexa */
	while (from < to) {
	int i;

	fprintf(o, " %04x: ", from);
	for (i = 0; ((from + i) < to) && (i < 16) ; i++) {
	fprintf(o, "%02x ", (unsigned char)b->data[from + i]);
	if (((from + i) & 15) == 7)
	fprintf(o, "- ");
	}
	if (to - from < 16) {
	int j = 0;

	for (j = 0; j < from + 16 - to; j++)
	fprintf(o, " ");
	if (j > 8)
	fprintf(o, " ");
	}
	fprintf(o, " ");
	for (i = 0; (from + i < to) && (i < 16) ; i++) {
	fprintf(o, "%c", isprint((int)b->data[from + i]) ? b->data[from + i] : '.') ;
	if ((((from + i) & 15) == 15) && ((from + i) != to-1))
	fprintf(o, "\n");
	}
	from += i;
	}
	fprintf(o, "\n--\n");
	fflush(o);
	}

	void __offer_buffer(void *from, unsigned int threshold)
	{
	struct buffer_wait wait, bak;
	int avail;

	/* For now, we consider that all objects need 1 buffer, so we can stop
	* waking up them once we have enough of them to eat all the available
	* buffers. Note that we don't really know if they are streams or just
	* other tasks, but that's a rough estimate. Similarly, for each cached
	* event we'll need 1 buffer. If no buffer is currently used, always
	* wake up the number of tasks we can offer a buffer based on what is
	* allocated, and in any case at least one task per two reserved
	* buffers.
	*/
	avail = pool2_buffer->allocated - pool2_buffer->used - global.tune.reserved_bufs / 2;

	list_for_each_entry_safe(wait, bak, &buffer_wq, list) {
	if (avail <= threshold)
	break;

	if (wait->target == from \|\| !wait->wakeup_cb(wait->target))
	continue;

	LIST_DEL(&wait->list);
	LIST_INIT(&wait->list);

	avail--;
	}
	}

	/*
	* Local variables:
	* c-indent-level: 8
	* c-basic-offset: 8
	* End:
	*/