blob: 177ab5a88d02ff9bf27152cc18273562d8781feb [file] [log] [blame]
/*
* Channel 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 <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <common/config.h>
#include <common/memory.h>
#include <common/buffer.h>
#include <proto/channel.h>
struct pool_head *pool2_channel;
/* perform minimal intializations, report 0 in case of error, 1 if OK. */
int init_channel()
{
pool2_channel = create_pool("channel", sizeof(struct channel), MEM_F_SHARED);
return pool2_channel != NULL;
}
/* 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, in 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 new_forward;
unsigned int forwarded;
forwarded = chn->buf->i;
b_adv(chn->buf, chn->buf->i);
/* Note: the case below is the only case where we may return
* a byte count that does not fit into a 32-bit number.
*/
if (likely(chn->to_forward == CHN_INFINITE_FORWARD))
return bytes;
if (likely(bytes == CHN_INFINITE_FORWARD)) {
chn->to_forward = bytes;
return bytes;
}
new_forward = chn->to_forward + bytes - forwarded;
bytes = forwarded; /* at least those bytes were scheduled */
if (new_forward <= chn->to_forward) {
/* integer overflow detected, let's assume no more than 2G at once */
new_forward = MID_RANGE(new_forward);
}
if (new_forward > chn->to_forward) {
bytes += new_forward - chn->to_forward;
chn->to_forward = new_forward;
}
return bytes;
}
/* 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 bo_inject(struct channel *chn, const char *msg, int len)
{
int max;
if (len == 0)
return -1;
if (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;
}
max = buffer_realign(chn->buf);
if (len > max)
return max;
memcpy(chn->buf->p, msg, len);
chn->buf->o += len;
chn->buf->p = b_ptr(chn->buf, 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.
* Channel flag CF_WAKE_WRITE is set if the write fails because the buffer is
* full.
*/
int bi_putchr(struct channel *chn, char c)
{
if (unlikely(channel_input_closed(chn)))
return -2;
if (!channel_may_recv(chn)) {
chn->flags |= CF_WAKE_WRITE;
return -1;
}
*bi_end(chn->buf) = c;
chn->buf->i++;
chn->flags |= CF_READ_PARTIAL;
if (chn->to_forward >= 1) {
if (chn->to_forward != CHN_INFINITE_FORWARD)
chn->to_forward--;
b_adv(chn->buf, 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. Channel flag CF_WAKE_WRITE is set if the write fails because
* the buffer is full.
*/
int bi_putblk(struct channel *chn, const char *blk, int len)
{
int max;
if (unlikely(channel_input_closed(chn)))
return -2;
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;
chn->flags |= CF_WAKE_WRITE;
return -1;
}
if (unlikely(len == 0))
return 0;
/* OK so the data fits in the buffer in one or two blocks */
max = buffer_contig_space(chn->buf);
memcpy(bi_end(chn->buf), 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;
}
b_adv(chn->buf, 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 *bi_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)) {
chn->flags |= CF_WAKE_WRITE;
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;
}
b_adv(chn->buf, 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 bo_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 bo_getline(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 = bo_ptr(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 bo_skip() to
* update it.
*/
int bo_getblk(struct channel *chn, char *blk, int len, int offset)
{
int firstblock;
if (chn->flags & CF_SHUTW)
return -1;
if (len + offset > chn->buf->o) {
if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
return -1;
return 0;
}
firstblock = chn->buf->data + chn->buf->size - bo_ptr(chn->buf);
if (firstblock > offset) {
if (firstblock >= len + offset) {
memcpy(blk, bo_ptr(chn->buf) + offset, len);
return len;
}
memcpy(blk, bo_ptr(chn->buf) + offset, firstblock - offset);
memcpy(blk + firstblock - offset, chn->buf->data, len - firstblock + offset);
return len;
}
memcpy(blk, chn->buf->data + offset - firstblock, len);
return len;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/