blob: b3382a76312eb97fba282dfdd0a670adee23a211 [file] [log] [blame]
/*
* 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 <common/config.h>
#include <common/buffer.h>
#include <proto/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, chn->buf->i);
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(chn->buf->i, 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 > chn->buf->size) {
/* 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(chn->buf->p, msg, len);
chn->buf->o += len;
chn->buf->p = c_ptr(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;
chn->buf->i++;
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 - buffer_len(chn->buf))) {
/* we can't write this chunk right now because the buffer is
* almost full or because the block is too large. Return the
* available space or -2 if impossible.
*/
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(chn->buf->data, blk + max, len - max);
chn->buf->i += len;
chn->total += len;
if (chn->to_forward) {
unsigned long fwd = len;
if (chn->to_forward != CHN_INFINITE_FORWARD) {
if (fwd > chn->to_forward)
fwd = chn->to_forward;
chn->to_forward -= fwd;
}
c_adv(chn, fwd);
}
/* notify that some data was read from the SI into the buffer */
chn->flags |= CF_READ_PARTIAL;
return len;
}
/* Tries to copy the whole buffer <buf> into the channel's buffer after length
* controls. It will only succeed if the target buffer is empty, in which case
* it will simply swap the buffers. The buffer not attached to the channel is
* returned so that the caller can store it locally. The chn->buf->o and
* to_forward pointers are updated. If the output buffer is a dummy buffer or
* if it still contains data <buf> is returned, indicating that nothing could
* be done. Channel flag READ_PARTIAL is updated if some data can be transferred.
* The chunk's length is updated with the number of bytes sent. On errors, NULL
* is returned. Note that only buf->i is considered.
*/
struct buffer *ci_swpbuf(struct channel *chn, struct buffer *buf)
{
struct buffer *old;
if (unlikely(channel_input_closed(chn)))
return NULL;
if (!chn->buf->size || !buffer_empty(chn->buf))
return buf;
old = chn->buf;
chn->buf = buf;
if (!buf->i)
return old;
chn->total += buf->i;
if (chn->to_forward) {
unsigned long fwd = buf->i;
if (chn->to_forward != CHN_INFINITE_FORWARD) {
if (fwd > chn->to_forward)
fwd = chn->to_forward;
chn->to_forward -= fwd;
}
c_adv(chn, fwd);
}
/* notify that some data was read from the SI into the buffer */
chn->flags |= CF_READ_PARTIAL;
return old;
}
/* 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 = b_head(chn->buf);
if (max > chn->buf->o) {
max = chn->buf->o;
str[max-1] = 0;
}
while (max) {
*str++ = *p;
ret++;
max--;
if (*p == '\n')
break;
p = buffer_wrap_add(chn->buf, p + 1);
}
if (ret > 0 && ret < len &&
(ret < chn->buf->o || 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 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(chn->buf->o == 0)) {
if (chn->flags & CF_SHUTW)
return -1;
return 0;
}
return b_getblk_nc(chn->buf, blk1, len1, blk2, len2, 0, chn->buf->o);
}
/* 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) {
/* 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(chn->buf->i == 0)) {
if (chn->flags & CF_SHUTR)
return -1;
return 0;
}
if (unlikely(chn->buf->p + chn->buf->i > chn->buf->data + chn->buf->size)) {
*blk1 = chn->buf->p;
*len1 = chn->buf->data + chn->buf->size - chn->buf->p;
*blk2 = chn->buf->data;
*len2 = chn->buf->i - *len1;
return 2;
}
*blk1 = chn->buf->p;
*len1 = chn->buf->i;
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;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/