src/channel.c - haproxy - Gitiles

 /*
  * Channel management functions.
  *
  * Copyright 2000-2014 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 <stdarg.h>
 #include <stdio.h>
 #include <string.h>

 #include <haproxy/api.h>
 #include <haproxy/buf.h>
 #include <haproxy/channel.h>


 /* Schedule up to <bytes> more bytes to be forwarded via the channel without
  * notifying the owner task. Any data pending in the buffer are scheduled to be
  * sent as well, within the limit of the number of bytes to forward. This must
  * be the only method to use to schedule bytes to be forwarded. If the requested
  * number is too large, it is automatically adjusted. The number of bytes taken
  * into account is returned. Directly touching ->to_forward will cause lockups
  * when buf->o goes down to zero if nobody is ready to push the remaining data.
  */
 unsigned long long __channel_forward(struct channel *chn, unsigned long long bytes)
 {
 	unsigned int budget;
 	unsigned int forwarded;

 	/* This is more of a safety measure as it's not supposed to happen in
 	 * regular code paths.
 	 */
 	if (unlikely(chn->to_forward == CHN_INFINITE_FORWARD)) {
 		c_adv(chn, ci_data(chn));
 		return bytes;
 	}

 	/* Bound the transferred size to a 32-bit count since all our values
 	 * are 32-bit, and we don't want to reach CHN_INFINITE_FORWARD.
 	 */
 	budget = MIN(bytes, CHN_INFINITE_FORWARD - 1);

 	/* transfer as much as we can of buf->i */
 	forwarded = MIN(ci_data(chn), budget);
 	c_adv(chn, forwarded);
 	budget -= forwarded;

 	if (!budget)
 		return forwarded;

 	/* Now we must ensure chn->to_forward sats below CHN_INFINITE_FORWARD,
 	 * which also implies it won't overflow. It's less operations in 64-bit.
 	 */
 	bytes = (unsigned long long)chn->to_forward + budget;
 	if (bytes >= CHN_INFINITE_FORWARD)
 		bytes = CHN_INFINITE_FORWARD - 1;
 	budget = bytes - chn->to_forward;

 	chn->to_forward += budget;
 	forwarded += budget;
 	return forwarded;
 }

 /* writes <len> bytes from message <msg> to the channel's buffer. Returns -1 in
  * case of success, -2 if the message is larger than the buffer size, or the
  * number of bytes available otherwise. The send limit is automatically
  * adjusted to the amount of data written. FIXME-20060521: handle unaligned
  * data. Note: this function appends data to the buffer's output and possibly
  * overwrites any pending input data which are assumed not to exist.
  */
 int co_inject(struct channel *chn, const char *msg, int len)
 {
 	int max;

 	if (len == 0)
 		return -1;

 	if (len < 0 || len > c_size(chn)) {
 		/* we can't write this chunk and will never be able to, because
 		 * it is larger than the buffer. This must be reported as an
 		 * error. Then we return -2 so that writers that don't care can
 		 * ignore it and go on, and others can check for this value.
 		 */
 		return -2;
 	}

 	c_realign_if_empty(chn);
 	max = b_contig_space(&chn->buf);
 	if (len > max)
 		return max;

 	memcpy(co_tail(chn), msg, len);
 	b_add(&chn->buf, len);
 	c_adv(chn, len);
 	chn->total += len;
 	return -1;
 }

 /* Tries to copy character <c> into the channel's buffer after some length
  * controls. The chn->o and to_forward pointers are updated. If the channel
  * input is closed, -2 is returned. If there is not enough room left in the
  * buffer, -1 is returned. Otherwise the number of bytes copied is returned
  * (1). Channel flag READ_PARTIAL is updated if some data can be transferred.
  */
 int ci_putchr(struct channel *chn, char c)
 {
 	if (unlikely(channel_input_closed(chn)))
 		return -2;

 	if (!channel_may_recv(chn))
 		return -1;

 	*ci_tail(chn) = c;

 	b_add(&chn->buf, 1);
 	chn->flags |= CF_READ_PARTIAL;

 	if (chn->to_forward >= 1) {
 		if (chn->to_forward != CHN_INFINITE_FORWARD)
 			chn->to_forward--;
 		c_adv(chn, 1);
 	}

 	chn->total++;
 	return 1;
 }

 /* Tries to copy block <blk> at once into the channel's buffer after length
  * controls. The chn->o and to_forward pointers are updated. If the channel
  * input is closed, -2 is returned. If the block is too large for this buffer,
  * -3 is returned. If there is not enough room left in the buffer, -1 is
  * returned. Otherwise the number of bytes copied is returned (0 being a valid
  * number). Channel flag READ_PARTIAL is updated if some data can be
  * transferred.
  */
 int ci_putblk(struct channel *chn, const char *blk, int len)
 {
 	int max;

 	if (unlikely(channel_input_closed(chn)))
 		return -2;

 	if (len < 0)
 		return -3;

 	max = channel_recv_limit(chn);
 	if (unlikely(len > max - c_data(chn))) {
 		/* we can't write this chunk right now because the buffer is
 		 * almost full or because the block is too large. Returns
 		 * -3 if block is too large for this buffer. Or -1 if the
 		 * room left is not large enough.
 		 */
 		if (len > max)
 			return -3;

 		return -1;
 	}

 	if (unlikely(len == 0))
 		return 0;

 	/* OK so the data fits in the buffer in one or two blocks */
 	max = b_contig_space(&chn->buf);
 	memcpy(ci_tail(chn), blk, MIN(len, max));
 	if (len > max)
 		memcpy(c_orig(chn), blk + max, len - max);

 	b_add(&chn->buf, len);
 	channel_add_input(chn, len);
 	return len;
 }

 /* Gets one text word out of a channel's buffer from a stream interface.
  * Return values :
  *   >0 : number of bytes read. Includes the sep if present before len or end.
  *   =0 : no sep before end found. <str> is left undefined.
  *   <0 : no more bytes readable because output is shut.
  * The channel status is not changed. The caller must call co_skip() to
  * update it. The line separator is waited for as long as neither the buffer
  * nor the output are full. If either of them is full, the string may be
  * returned as is, without the line separator.
  */
 int co_getword(const struct channel *chn, char *str, int len, char sep)
 {
 	int ret, max;
 	char *p;

 	ret = 0;
 	max = len;

 	/* closed or empty + imminent close = -1; empty = 0 */
 	if (unlikely((chn->flags & CF_SHUTW) || channel_is_empty(chn))) {
 		if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
 			ret = -1;
 		goto out;
 	}

 	p = co_head(chn);

 	if (max > co_data(chn)) {
 		max = co_data(chn);
 		str[max-1] = 0;
 	}
 	while (max) {
 		*str++ = *p;
 		ret++;
 		max--;

 		if (*p == sep)
 			break;
 		p = b_next(&chn->buf, p);
 	}
 	if (ret > 0 && ret < len &&
 	    (ret < co_data(chn) || channel_may_recv(chn)) &&
 	    *(str-1) != sep &&
 	    !(chn->flags & (CF_SHUTW|CF_SHUTW_NOW)))
 		ret = 0;
  out:
 	if (max)
 		*str = 0;
 	return ret;
 }

 /* Gets one text line out of a channel's buffer from a stream interface.
  * Return values :
  *   >0 : number of bytes read. Includes the \n if present before len or end.
  *   =0 : no '\n' before end found. <str> is left undefined.
  *   <0 : no more bytes readable because output is shut.
  * The channel status is not changed. The caller must call co_skip() to
  * update it. The '\n' is waited for as long as neither the buffer nor the
  * output are full. If either of them is full, the string may be returned
  * as is, without the '\n'.
  */
 int co_getline(const struct channel *chn, char *str, int len)
 {
 	int ret, max;
 	char *p;

 	ret = 0;
 	max = len;

 	/* closed or empty + imminent close = -1; empty = 0 */
 	if (unlikely((chn->flags & CF_SHUTW) || channel_is_empty(chn))) {
 		if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
 			ret = -1;
 		goto out;
 	}

 	p = co_head(chn);

 	if (max > co_data(chn)) {
 		max = co_data(chn);
 		str[max-1] = 0;
 	}
 	while (max) {
 		*str++ = *p;
 		ret++;
 		max--;

 		if (*p == '\n')
 			break;
 		p = b_next(&chn->buf, p);
 	}
 	if (ret > 0 && ret < len &&
 	    (ret < co_data(chn) || channel_may_recv(chn)) &&
 	    *(str-1) != '\n' &&
 	    !(chn->flags & (CF_SHUTW|CF_SHUTW_NOW)))
 		ret = 0;
  out:
 	if (max)
 		*str = 0;
 	return ret;
 }

 /* Gets one char of data from a channel's buffer,
  * Return values :
  *    1 : number of bytes read, equal to requested size.
  *   =0 : not enough data available. <c> is left undefined.
  *   <0 : no more bytes readable because output is shut.
  * The channel status is not changed. The caller must call co_skip() to
  * update it.
  */
 int co_getchar(const struct channel *chn, char *c)
 {
 	if (chn->flags & CF_SHUTW)
 		return -1;

 	if (unlikely(co_data(chn) == 0)) {
 		if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
 			return -1;
 		return 0;
 	}

 	*c = *(co_head(chn));
 	return 1;
 }

 /* Gets one full block of data at once from a channel's buffer, optionally from
  * a specific offset. Return values :
  *   >0 : number of bytes read, equal to requested size.
  *   =0 : not enough data available. <blk> is left undefined.
  *   <0 : no more bytes readable because output is shut.
  * The channel status is not changed. The caller must call co_skip() to
  * update it.
  */
 int co_getblk(const struct channel *chn, char *blk, int len, int offset)
 {
 	if (chn->flags & CF_SHUTW)
 		return -1;

 	if (len + offset > co_data(chn)) {
 		if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
 			return -1;
 		return 0;
 	}

 	return b_getblk(&chn->buf, blk, len, offset);
 }

 /* Gets one or two blocks of data at once from a channel's output buffer.
  * Return values :
  *   >0 : number of blocks filled (1 or 2). blk1 is always filled before blk2.
  *   =0 : not enough data available. <blk*> are left undefined.
  *   <0 : no more bytes readable because output is shut.
  * The channel status is not changed. The caller must call co_skip() to
  * update it. Unused buffers are left in an undefined state.
  */
 int co_getblk_nc(const struct channel *chn, const char **blk1, size_t *len1, const char **blk2, size_t *len2)
 {
 	if (unlikely(co_data(chn) == 0)) {
 		if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
 			return -1;
 		return 0;
 	}

 	return b_getblk_nc(&chn->buf, blk1, len1, blk2, len2, 0, co_data(chn));
 }

 /* Gets one text line out of a channel's output buffer from a stream interface.
  * Return values :
  *   >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
  *   =0 : not enough data available.
  *   <0 : no more bytes readable because output is shut.
  * The '\n' is waited for as long as neither the buffer nor the output are
  * full. If either of them is full, the string may be returned as is, without
  * the '\n'. Unused buffers are left in an undefined state.
  */
 int co_getline_nc(const struct channel *chn,
                   const char **blk1, size_t *len1,
                   const char **blk2, size_t *len2)
 {
 	int retcode;
 	int l;

 	retcode = co_getblk_nc(chn, blk1, len1, blk2, len2);
 	if (unlikely(retcode <= 0))
 		return retcode;

 	for (l = 0; l < *len1 && (*blk1)[l] != '\n'; l++);
 	if (l < *len1 && (*blk1)[l] == '\n') {
 		*len1 = l + 1;
 		return 1;
 	}

 	if (retcode >= 2) {
 		for (l = 0; l < *len2 && (*blk2)[l] != '\n'; l++);
 		if (l < *len2 && (*blk2)[l] == '\n') {
 			*len2 = l + 1;
 			return 2;
 		}
 	}

 	if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW)) {
 		/* If we have found no LF and the buffer is shut, then
 		 * the resulting string is made of the concatenation of
 		 * the pending blocks (1 or 2).
 		 */
 		return retcode;
 	}

 	/* No LF yet and not shut yet */
 	return 0;
 }

 /* Gets one full block of data at once from a channel's input buffer.
  * This function can return the data slitted in one or two blocks.
  * Return values :
  *   >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
  *   =0 : not enough data available.
  *   <0 : no more bytes readable because input is shut.
  */
 int ci_getblk_nc(const struct channel *chn,
                  char **blk1, size_t *len1,
                  char **blk2, size_t *len2)
 {
 	if (unlikely(ci_data(chn) == 0)) {
 		if (chn->flags & CF_SHUTR)
 			return -1;
 		return 0;
 	}

 	if (unlikely(ci_head(chn) + ci_data(chn) > c_wrap(chn))) {
 		*blk1 = ci_head(chn);
 		*len1 = c_wrap(chn) - ci_head(chn);
 		*blk2 = c_orig(chn);
 		*len2 = ci_data(chn) - *len1;
 		return 2;
 	}

 	*blk1 = ci_head(chn);
 	*len1 = ci_data(chn);
 	return 1;
 }

 /* Gets one text line out of a channel's input buffer from a stream interface.
  * Return values :
  *   >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
  *   =0 : not enough data available.
  *   <0 : no more bytes readable because output is shut.
  * The '\n' is waited for as long as neither the buffer nor the input are
  * full. If either of them is full, the string may be returned as is, without
  * the '\n'. Unused buffers are left in an undefined state.
  */
 int ci_getline_nc(const struct channel *chn,
                   char **blk1, size_t *len1,
                   char **blk2, size_t *len2)
 {
 	int retcode;
 	int l;

 	retcode = ci_getblk_nc(chn, blk1, len1, blk2, len2);
 	if (unlikely(retcode <= 0))
 		return retcode;

 	for (l = 0; l < *len1 && (*blk1)[l] != '\n'; l++);
 	if (l < *len1 && (*blk1)[l] == '\n') {
 		*len1 = l + 1;
 		return 1;
 	}

 	if (retcode >= 2) {
 		for (l = 0; l < *len2 && (*blk2)[l] != '\n'; l++);
 		if (l < *len2 && (*blk2)[l] == '\n') {
 			*len2 = l + 1;
 			return 2;
 		}
 	}

 	if (chn->flags & CF_SHUTW) {
 		/* If we have found no LF and the buffer is shut, then
 		 * the resulting string is made of the concatenation of
 		 * the pending blocks (1 or 2).
 		 */
 		return retcode;
 	}

 	/* No LF yet and not shut yet */
 	return 0;
 }

 /* Inserts <str> followed by "\r\n" at position <pos> relative to channel <c>'s
  * input head. The <len> argument informs about the length of string <str> so
  * that we don't have to measure it. <str> must be a valid pointer and must not
  * include the trailing "\r\n".
  *
  * The number of bytes added is returned on success. 0 is returned on failure.
  */
 int ci_insert_line2(struct channel *c, int pos, const char *str, int len)
 {
 	struct buffer *b = &c->buf;
 	char *dst = c_ptr(c, pos);
 	int delta;

 	delta = len + 2;

 	if (__b_tail(b) + delta >= b_wrap(b))
 		return 0;  /* no space left */

 	if (b_data(b) &&
 	    b_tail(b) + delta > b_head(b) &&
 	    b_head(b) >= b_tail(b))
 		return 0;  /* no space left before wrapping data */

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

 	/* now, copy str over dst */
 	memcpy(dst, str, len);
 	dst[len] = '\r';
 	dst[len + 1] = '\n';

 	b_add(b, delta);
 	return delta;
 }

 /*
  * Local variables:
  *  c-indent-level: 8
  *  c-basic-offset: 8
  * End:
  */
	/*
	* Channel management functions.
	*
	* Copyright 2000-2014 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 <stdarg.h>
	#include <stdio.h>
	#include <string.h>

	#include <haproxy/api.h>
	#include <haproxy/buf.h>
	#include <haproxy/channel.h>


	/* Schedule up to <bytes> more bytes to be forwarded via the channel without
	* notifying the owner task. Any data pending in the buffer are scheduled to be
	* sent as well, within the limit of the number of bytes to forward. This must
	* be the only method to use to schedule bytes to be forwarded. If the requested
	* number is too large, it is automatically adjusted. The number of bytes taken
	* into account is returned. Directly touching ->to_forward will cause lockups
	* when buf->o goes down to zero if nobody is ready to push the remaining data.
	*/
	unsigned long long __channel_forward(struct channel *chn, unsigned long long bytes)
	{
	unsigned int budget;
	unsigned int forwarded;

	/* This is more of a safety measure as it's not supposed to happen in
	* regular code paths.
	*/
	if (unlikely(chn->to_forward == CHN_INFINITE_FORWARD)) {
	c_adv(chn, ci_data(chn));
	return bytes;
	}

	/* Bound the transferred size to a 32-bit count since all our values
	* are 32-bit, and we don't want to reach CHN_INFINITE_FORWARD.
	*/
	budget = MIN(bytes, CHN_INFINITE_FORWARD - 1);

	/* transfer as much as we can of buf->i */
	forwarded = MIN(ci_data(chn), budget);
	c_adv(chn, forwarded);
	budget -= forwarded;

	if (!budget)
	return forwarded;

	/* Now we must ensure chn->to_forward sats below CHN_INFINITE_FORWARD,
	* which also implies it won't overflow. It's less operations in 64-bit.
	*/
	bytes = (unsigned long long)chn->to_forward + budget;
	if (bytes >= CHN_INFINITE_FORWARD)
	bytes = CHN_INFINITE_FORWARD - 1;
	budget = bytes - chn->to_forward;

	chn->to_forward += budget;
	forwarded += budget;
	return forwarded;
	}

	/* writes <len> bytes from message <msg> to the channel's buffer. Returns -1 in
	* case of success, -2 if the message is larger than the buffer size, or the
	* number of bytes available otherwise. The send limit is automatically
	* adjusted to the amount of data written. FIXME-20060521: handle unaligned
	* data. Note: this function appends data to the buffer's output and possibly
	* overwrites any pending input data which are assumed not to exist.
	*/
	int co_inject(struct channel chn, const char msg, int len)
	{
	int max;

	if (len == 0)
	return -1;

	if (len < 0 \|\| len > c_size(chn)) {
	/* we can't write this chunk and will never be able to, because
	* it is larger than the buffer. This must be reported as an
	* error. Then we return -2 so that writers that don't care can
	* ignore it and go on, and others can check for this value.
	*/
	return -2;
	}

	c_realign_if_empty(chn);
	max = b_contig_space(&chn->buf);
	if (len > max)
	return max;

	memcpy(co_tail(chn), msg, len);
	b_add(&chn->buf, len);
	c_adv(chn, len);
	chn->total += len;
	return -1;
	}

	/* Tries to copy character <c> into the channel's buffer after some length
	* controls. The chn->o and to_forward pointers are updated. If the channel
	* input is closed, -2 is returned. If there is not enough room left in the
	* buffer, -1 is returned. Otherwise the number of bytes copied is returned
	* (1). Channel flag READ_PARTIAL is updated if some data can be transferred.
	*/
	int ci_putchr(struct channel *chn, char c)
	{
	if (unlikely(channel_input_closed(chn)))
	return -2;

	if (!channel_may_recv(chn))
	return -1;

	*ci_tail(chn) = c;

	b_add(&chn->buf, 1);
	chn->flags \|= CF_READ_PARTIAL;

	if (chn->to_forward >= 1) {
	if (chn->to_forward != CHN_INFINITE_FORWARD)
	chn->to_forward--;
	c_adv(chn, 1);
	}

	chn->total++;
	return 1;
	}

	/* Tries to copy block <blk> at once into the channel's buffer after length
	* controls. The chn->o and to_forward pointers are updated. If the channel
	* input is closed, -2 is returned. If the block is too large for this buffer,
	* -3 is returned. If there is not enough room left in the buffer, -1 is
	* returned. Otherwise the number of bytes copied is returned (0 being a valid
	* number). Channel flag READ_PARTIAL is updated if some data can be
	* transferred.
	*/
	int ci_putblk(struct channel chn, const char blk, int len)
	{
	int max;

	if (unlikely(channel_input_closed(chn)))
	return -2;

	if (len < 0)
	return -3;

	max = channel_recv_limit(chn);
	if (unlikely(len > max - c_data(chn))) {
	/* we can't write this chunk right now because the buffer is
	* almost full or because the block is too large. Returns
	* -3 if block is too large for this buffer. Or -1 if the
	* room left is not large enough.
	*/
	if (len > max)
	return -3;

	return -1;
	}

	if (unlikely(len == 0))
	return 0;

	/* OK so the data fits in the buffer in one or two blocks */
	max = b_contig_space(&chn->buf);
	memcpy(ci_tail(chn), blk, MIN(len, max));
	if (len > max)
	memcpy(c_orig(chn), blk + max, len - max);

	b_add(&chn->buf, len);
	channel_add_input(chn, len);
	return len;
	}

	/* Gets one text word out of a channel's buffer from a stream interface.
	* Return values :
	* >0 : number of bytes read. Includes the sep if present before len or end.
	* =0 : no sep before end found. <str> is left undefined.
	* <0 : no more bytes readable because output is shut.
	* The channel status is not changed. The caller must call co_skip() to
	* update it. The line separator is waited for as long as neither the buffer
	* nor the output are full. If either of them is full, the string may be
	* returned as is, without the line separator.
	*/
	int co_getword(const struct channel chn, char str, int len, char sep)
	{
	int ret, max;
	char *p;

	ret = 0;
	max = len;

	/* closed or empty + imminent close = -1; empty = 0 */
	if (unlikely((chn->flags & CF_SHUTW) \|\| channel_is_empty(chn))) {
	if (chn->flags & (CF_SHUTW\|CF_SHUTW_NOW))
	ret = -1;
	goto out;
	}

	p = co_head(chn);

	if (max > co_data(chn)) {
	max = co_data(chn);
	str[max-1] = 0;
	}
	while (max) {
	str++ = p;
	ret++;
	max--;

	if (*p == sep)
	break;
	p = b_next(&chn->buf, p);
	}
	if (ret > 0 && ret < len &&
	(ret < co_data(chn) \|\| channel_may_recv(chn)) &&
	*(str-1) != sep &&
	!(chn->flags & (CF_SHUTW\|CF_SHUTW_NOW)))
	ret = 0;
	out:
	if (max)
	*str = 0;
	return ret;
	}

	/* Gets one text line out of a channel's buffer from a stream interface.
	* Return values :
	* >0 : number of bytes read. Includes the \n if present before len or end.
	* =0 : no '\n' before end found. <str> is left undefined.
	* <0 : no more bytes readable because output is shut.
	* The channel status is not changed. The caller must call co_skip() to
	* update it. The '\n' is waited for as long as neither the buffer nor the
	* output are full. If either of them is full, the string may be returned
	* as is, without the '\n'.
	*/
	int co_getline(const struct channel chn, char str, int len)
	{
	int ret, max;
	char *p;

	ret = 0;
	max = len;

	/* closed or empty + imminent close = -1; empty = 0 */
	if (unlikely((chn->flags & CF_SHUTW) \|\| channel_is_empty(chn))) {
	if (chn->flags & (CF_SHUTW\|CF_SHUTW_NOW))
	ret = -1;
	goto out;
	}

	p = co_head(chn);

	if (max > co_data(chn)) {
	max = co_data(chn);
	str[max-1] = 0;
	}
	while (max) {
	str++ = p;
	ret++;
	max--;

	if (*p == '\n')
	break;
	p = b_next(&chn->buf, p);
	}
	if (ret > 0 && ret < len &&
	(ret < co_data(chn) \|\| channel_may_recv(chn)) &&
	*(str-1) != '\n' &&
	!(chn->flags & (CF_SHUTW\|CF_SHUTW_NOW)))
	ret = 0;
	out:
	if (max)
	*str = 0;
	return ret;
	}

	/* Gets one char of data from a channel's buffer,
	* Return values :
	* 1 : number of bytes read, equal to requested size.
	* =0 : not enough data available. <c> is left undefined.
	* <0 : no more bytes readable because output is shut.
	* The channel status is not changed. The caller must call co_skip() to
	* update it.
	*/
	int co_getchar(const struct channel chn, char c)
	{
	if (chn->flags & CF_SHUTW)
	return -1;

	if (unlikely(co_data(chn) == 0)) {
	if (chn->flags & (CF_SHUTW\|CF_SHUTW_NOW))
	return -1;
	return 0;
	}

	c = (co_head(chn));
	return 1;
	}

	/* Gets one full block of data at once from a channel's buffer, optionally from
	* a specific offset. Return values :
	* >0 : number of bytes read, equal to requested size.
	* =0 : not enough data available. <blk> is left undefined.
	* <0 : no more bytes readable because output is shut.
	* The channel status is not changed. The caller must call co_skip() to
	* update it.
	*/
	int co_getblk(const struct channel chn, char blk, int len, int offset)
	{
	if (chn->flags & CF_SHUTW)
	return -1;

	if (len + offset > co_data(chn)) {
	if (chn->flags & (CF_SHUTW\|CF_SHUTW_NOW))
	return -1;
	return 0;
	}

	return b_getblk(&chn->buf, blk, len, offset);
	}

	/* Gets one or two blocks of data at once from a channel's output buffer.
	* Return values :
	* >0 : number of blocks filled (1 or 2). blk1 is always filled before blk2.
	* =0 : not enough data available. <blk*> are left undefined.
	* <0 : no more bytes readable because output is shut.
	* The channel status is not changed. The caller must call co_skip() to
	* update it. Unused buffers are left in an undefined state.
	*/
	int co_getblk_nc(const struct channel chn, const char blk1, size_t len1, const char *blk2, size_t len2)
	{
	if (unlikely(co_data(chn) == 0)) {
	if (chn->flags & (CF_SHUTW\|CF_SHUTW_NOW))
	return -1;
	return 0;
	}

	return b_getblk_nc(&chn->buf, blk1, len1, blk2, len2, 0, co_data(chn));
	}

	/* Gets one text line out of a channel's output buffer from a stream interface.
	* Return values :
	* >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
	* =0 : not enough data available.
	* <0 : no more bytes readable because output is shut.
	* The '\n' is waited for as long as neither the buffer nor the output are
	* full. If either of them is full, the string may be returned as is, without
	* the '\n'. Unused buffers are left in an undefined state.
	*/
	int co_getline_nc(const struct channel *chn,
	const char *blk1, size_t len1,
	const char *blk2, size_t len2)
	{
	int retcode;
	int l;

	retcode = co_getblk_nc(chn, blk1, len1, blk2, len2);
	if (unlikely(retcode <= 0))
	return retcode;

	for (l = 0; l < len1 && (blk1)[l] != '\n'; l++);
	if (l < len1 && (blk1)[l] == '\n') {
	*len1 = l + 1;
	return 1;
	}

	if (retcode >= 2) {
	for (l = 0; l < len2 && (blk2)[l] != '\n'; l++);
	if (l < len2 && (blk2)[l] == '\n') {
	*len2 = l + 1;
	return 2;
	}
	}

	if (chn->flags & (CF_SHUTW\|CF_SHUTW_NOW)) {
	/* If we have found no LF and the buffer is shut, then
	* the resulting string is made of the concatenation of
	* the pending blocks (1 or 2).
	*/
	return retcode;
	}

	/* No LF yet and not shut yet */
	return 0;
	}

	/* Gets one full block of data at once from a channel's input buffer.
	* This function can return the data slitted in one or two blocks.
	* Return values :
	* >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
	* =0 : not enough data available.
	* <0 : no more bytes readable because input is shut.
	*/
	int ci_getblk_nc(const struct channel *chn,
	char *blk1, size_t len1,
	char *blk2, size_t len2)
	{
	if (unlikely(ci_data(chn) == 0)) {
	if (chn->flags & CF_SHUTR)
	return -1;
	return 0;
	}

	if (unlikely(ci_head(chn) + ci_data(chn) > c_wrap(chn))) {
	*blk1 = ci_head(chn);
	*len1 = c_wrap(chn) - ci_head(chn);
	*blk2 = c_orig(chn);
	len2 = ci_data(chn) - len1;
	return 2;
	}

	*blk1 = ci_head(chn);
	*len1 = ci_data(chn);
	return 1;
	}

	/* Gets one text line out of a channel's input buffer from a stream interface.
	* Return values :
	* >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
	* =0 : not enough data available.
	* <0 : no more bytes readable because output is shut.
	* The '\n' is waited for as long as neither the buffer nor the input are
	* full. If either of them is full, the string may be returned as is, without
	* the '\n'. Unused buffers are left in an undefined state.
	*/
	int ci_getline_nc(const struct channel *chn,
	char *blk1, size_t len1,
	char *blk2, size_t len2)
	{
	int retcode;
	int l;

	retcode = ci_getblk_nc(chn, blk1, len1, blk2, len2);
	if (unlikely(retcode <= 0))
	return retcode;

	for (l = 0; l < len1 && (blk1)[l] != '\n'; l++);
	if (l < len1 && (blk1)[l] == '\n') {
	*len1 = l + 1;
	return 1;
	}

	if (retcode >= 2) {
	for (l = 0; l < len2 && (blk2)[l] != '\n'; l++);
	if (l < len2 && (blk2)[l] == '\n') {
	*len2 = l + 1;
	return 2;
	}
	}

	if (chn->flags & CF_SHUTW) {
	/* If we have found no LF and the buffer is shut, then
	* the resulting string is made of the concatenation of
	* the pending blocks (1 or 2).
	*/
	return retcode;
	}

	/* No LF yet and not shut yet */
	return 0;
	}

	/* Inserts <str> followed by "\r\n" at position <pos> relative to channel <c>'s
	* input head. The <len> argument informs about the length of string <str> so
	* that we don't have to measure it. <str> must be a valid pointer and must not
	* include the trailing "\r\n".
	*
	* The number of bytes added is returned on success. 0 is returned on failure.
	*/
	int ci_insert_line2(struct channel c, int pos, const char str, int len)
	{
	struct buffer *b = &c->buf;
	char *dst = c_ptr(c, pos);
	int delta;

	delta = len + 2;

	if (__b_tail(b) + delta >= b_wrap(b))
	return 0; /* no space left */

	if (b_data(b) &&
	b_tail(b) + delta > b_head(b) &&
	b_head(b) >= b_tail(b))
	return 0; /* no space left before wrapping data */

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

	/* now, copy str over dst */
	memcpy(dst, str, len);
	dst[len] = '\r';
	dst[len + 1] = '\n';

	b_add(b, delta);
	return delta;
	}

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