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/*
* 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:
*/