| /* |
| * include/common/buffer.h |
| * Buffer management definitions, macros and inline functions. |
| * |
| * Copyright (C) 2000-2012 Willy Tarreau - w@1wt.eu |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation, version 2.1 |
| * exclusively. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef _COMMON_BUFFER_H |
| #define _COMMON_BUFFER_H |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include <common/buf.h> |
| #include <common/chunk.h> |
| #include <common/config.h> |
| #include <common/ist.h> |
| #include <common/memory.h> |
| |
| |
| /* an element of the <buffer_wq> list. It represents an object that need to |
| * acquire a buffer to continue its process. */ |
| struct buffer_wait { |
| void *target; /* The waiting object that should be woken up */ |
| int (*wakeup_cb)(void *); /* The function used to wake up the <target>, passed as argument */ |
| struct list list; /* Next element in the <buffer_wq> list */ |
| }; |
| |
| extern struct pool_head *pool_head_buffer; |
| extern struct buffer buf_empty; |
| extern struct buffer buf_wanted; |
| extern struct list buffer_wq; |
| __decl_hathreads(extern HA_SPINLOCK_T buffer_wq_lock); |
| |
| int init_buffer(); |
| void deinit_buffer(); |
| int buffer_replace2(struct buffer *b, char *pos, char *end, const char *str, int len); |
| int buffer_insert_line2(struct buffer *b, char *pos, const char *str, int len); |
| void buffer_dump(FILE *o, struct buffer *b, int from, int to); |
| |
| /*****************************************************************/ |
| /* These functions are used to compute various buffer area sizes */ |
| /*****************************************************************/ |
| |
| |
| /* Return the buffer's length in bytes by summing the input and the output */ |
| static inline int buffer_len(const struct buffer *buf) |
| { |
| return buf->i + buf->o; |
| } |
| |
| /* Return non-zero only if the buffer is not empty */ |
| static inline int buffer_not_empty(const struct buffer *buf) |
| { |
| return buf->i | buf->o; |
| } |
| |
| /* Return non-zero only if the buffer is empty */ |
| static inline int buffer_empty(const struct buffer *buf) |
| { |
| return !buffer_not_empty(buf); |
| } |
| |
| /* Returns non-zero if the buffer's INPUT is considered full, which means that |
| * it holds at least as much INPUT data as (size - reserve). This also means |
| * that data that are scheduled for output are considered as potential free |
| * space, and that the reserved space is always considered as not usable. This |
| * information alone cannot be used as a general purpose free space indicator. |
| * However it accurately indicates that too many data were fed in the buffer |
| * for an analyzer for instance. See the channel_may_recv() function for a more |
| * generic function taking everything into account. |
| */ |
| static inline int buffer_full(const struct buffer *b, unsigned int reserve) |
| { |
| if (b == &buf_empty) |
| return 0; |
| |
| return (b->i + reserve >= b->size); |
| } |
| |
| /* Normalizes a pointer after a subtract */ |
| static inline char *buffer_wrap_sub(const struct buffer *buf, char *ptr) |
| { |
| if (ptr < buf->data) |
| ptr += buf->size; |
| return ptr; |
| } |
| |
| /* Normalizes a pointer after an addition */ |
| static inline char *buffer_wrap_add(const struct buffer *buf, char *ptr) |
| { |
| if (ptr - buf->size >= buf->data) |
| ptr -= buf->size; |
| return ptr; |
| } |
| |
| /* Return the maximum amount of bytes that can be written into the buffer, |
| * including reserved space which may be overwritten. |
| */ |
| static inline int buffer_total_space(const struct buffer *buf) |
| { |
| return buf->size - buffer_len(buf); |
| } |
| |
| /* Returns the amount of byte that can be written starting from <p> into the |
| * input buffer at once, including reserved space which may be overwritten. |
| * This is used by Lua to insert data in the input side just before the other |
| * data using buffer_replace(). The goal is to transfer these new data in the |
| * output buffer. |
| */ |
| static inline int bi_space_for_replace(const struct buffer *buf) |
| { |
| const char *end; |
| |
| /* If the input side data overflows, we cannot insert data contiguously. */ |
| if (buf->p + buf->i >= buf->data + buf->size) |
| return 0; |
| |
| /* Check the last byte used in the buffer, it may be a byte of the output |
| * side if the buffer wraps, or its the end of the buffer. |
| */ |
| end = buffer_wrap_sub(buf, buf->p - buf->o); |
| if (end <= buf->p) |
| end = buf->data + buf->size; |
| |
| /* Compute the amount of bytes which can be written. */ |
| return end - (buf->p + buf->i); |
| } |
| |
| |
| /* Normalizes a pointer which is supposed to be relative to the beginning of a |
| * buffer, so that wrapping is correctly handled. The intent is to use this |
| * when increasing a pointer. Note that the wrapping test is only performed |
| * once, so the original pointer must be between ->data-size and ->data+2*size-1, |
| * otherwise an invalid pointer might be returned. |
| */ |
| static inline const char *buffer_pointer(const struct buffer *buf, const char *ptr) |
| { |
| if (ptr < buf->data) |
| ptr += buf->size; |
| else if (ptr - buf->size >= buf->data) |
| ptr -= buf->size; |
| return ptr; |
| } |
| |
| /* Returns the distance between two pointers, taking into account the ability |
| * to wrap around the buffer's end. |
| */ |
| static inline int buffer_count(const struct buffer *buf, const char *from, const char *to) |
| { |
| int count = to - from; |
| |
| count += count < 0 ? buf->size : 0; |
| return count; |
| } |
| |
| /* returns the amount of pending bytes in the buffer. It is the amount of bytes |
| * that is not scheduled to be sent. |
| */ |
| static inline int buffer_pending(const struct buffer *buf) |
| { |
| return buf->i; |
| } |
| |
| /* Return 1 if the buffer has less than 1/4 of its capacity free, otherwise 0 */ |
| static inline int buffer_almost_full(const struct buffer *buf) |
| { |
| if (buf == &buf_empty) |
| return 0; |
| |
| return b_almost_full(buf); |
| } |
| |
| /* Cut the first <n> pending bytes in a contiguous buffer. It is illegal to |
| * call this function with remaining data waiting to be sent (o > 0). The |
| * caller must ensure that <n> is smaller than the actual buffer's length. |
| * This is mainly used to remove empty lines at the beginning of a request |
| * or a response. |
| */ |
| static inline void bi_fast_delete(struct buffer *buf, int n) |
| { |
| buf->i -= n; |
| buf->p += n; |
| } |
| |
| /* Schedule all remaining buffer data to be sent. ->o is not touched if it |
| * already covers those data. That permits doing a flush even after a forward, |
| * although not recommended. |
| */ |
| static inline void buffer_flush(struct buffer *buf) |
| { |
| buf->p = buffer_wrap_add(buf, buf->p + buf->i); |
| buf->o += buf->i; |
| buf->i = 0; |
| } |
| |
| /* 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, r, lr) 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. |
| */ |
| static inline int buffer_replace(struct buffer *b, char *pos, char *end, const char *str) |
| { |
| return buffer_replace2(b, pos, end, str, strlen(str)); |
| } |
| |
| /* Tries to write char <c> into output data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is full. |
| */ |
| static inline void bo_putchr(struct buffer *b, char c) |
| { |
| if (buffer_len(b) == b->size) |
| return; |
| *b->p = c; |
| b->p = b_peek(b, b->o + 1); |
| b->o++; |
| } |
| |
| /* Tries to copy block <blk> into output data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is too short. It returns the number of bytes |
| * copied. |
| */ |
| static inline int bo_putblk(struct buffer *b, const char *blk, int len) |
| { |
| int cur_len = buffer_len(b); |
| int half; |
| |
| if (len > b->size - cur_len) |
| len = (b->size - cur_len); |
| if (!len) |
| return 0; |
| |
| half = b_contig_space(b); |
| if (half > len) |
| half = len; |
| |
| memcpy(b->p, blk, half); |
| b->p = b_peek(b, b->o + half); |
| b->o += half; |
| if (len > half) { |
| memcpy(b->p, blk + half, len - half); |
| b->p = b_peek(b, b->o + len - half); |
| b->o += len - half; |
| } |
| return len; |
| } |
| |
| /* Tries to copy string <str> into output data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is too short. It returns the number of bytes |
| * copied. |
| */ |
| static inline int bo_putstr(struct buffer *b, const char *str) |
| { |
| return bo_putblk(b, str, strlen(str)); |
| } |
| |
| /* Tries to copy chunk <chk> into output data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is too short. It returns the number of bytes |
| * copied. |
| */ |
| static inline int bo_putchk(struct buffer *b, const struct chunk *chk) |
| { |
| return bo_putblk(b, chk->str, chk->len); |
| } |
| |
| /* Tries to write char <c> into input data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is full. |
| */ |
| static inline void bi_putchr(struct buffer *b, char c) |
| { |
| if (buffer_len(b) == b->size) |
| return; |
| *b_tail(b) = c; |
| b->i++; |
| } |
| |
| /* Tries to copy block <blk> into input data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is too short. It returns the number of bytes |
| * copied. |
| */ |
| static inline int bi_putblk(struct buffer *b, const char *blk, int len) |
| { |
| int cur_len = buffer_len(b); |
| int half; |
| |
| if (len > b->size - cur_len) |
| len = (b->size - cur_len); |
| if (!len) |
| return 0; |
| |
| half = b_contig_space(b); |
| if (half > len) |
| half = len; |
| |
| memcpy(b_tail(b), blk, half); |
| if (len > half) |
| memcpy(b_peek(b, b->o + b->i + half), blk + half, len - half); |
| b->i += len; |
| return len; |
| } |
| |
| /* Tries to copy string <str> into input data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is too short. It returns the number of bytes |
| * copied. |
| */ |
| static inline int bi_putstr(struct buffer *b, const char *str) |
| { |
| return bi_putblk(b, str, strlen(str)); |
| } |
| |
| /* Tries to copy chunk <chk> into input data at buffer <b>. Supports wrapping. |
| * Data are truncated if buffer is too short. It returns the number of bytes |
| * copied. |
| */ |
| static inline int bi_putchk(struct buffer *b, const struct chunk *chk) |
| { |
| return bi_putblk(b, chk->str, chk->len); |
| } |
| |
| /* Allocates a buffer and replaces *buf with this buffer. If no memory is |
| * available, &buf_wanted is used instead. No control is made to check if *buf |
| * already pointed to another buffer. The allocated buffer is returned, or |
| * NULL in case no memory is available. |
| */ |
| static inline struct buffer *b_alloc(struct buffer **buf) |
| { |
| struct buffer *b; |
| |
| *buf = &buf_wanted; |
| b = pool_alloc_dirty(pool_head_buffer); |
| if (likely(b)) { |
| b->size = pool_head_buffer->size - sizeof(struct buffer); |
| b_reset(b); |
| *buf = b; |
| } |
| return b; |
| } |
| |
| /* Allocates a buffer and replaces *buf with this buffer. If no memory is |
| * available, &buf_wanted is used instead. No control is made to check if *buf |
| * already pointed to another buffer. The allocated buffer is returned, or |
| * NULL in case no memory is available. The difference with b_alloc() is that |
| * this function only picks from the pool and never calls malloc(), so it can |
| * fail even if some memory is available. |
| */ |
| static inline struct buffer *b_alloc_fast(struct buffer **buf) |
| { |
| struct buffer *b; |
| |
| *buf = &buf_wanted; |
| b = pool_get_first(pool_head_buffer); |
| if (likely(b)) { |
| b->size = pool_head_buffer->size - sizeof(struct buffer); |
| b_reset(b); |
| *buf = b; |
| } |
| return b; |
| } |
| |
| /* Releases buffer *buf (no check of emptiness) */ |
| static inline void __b_drop(struct buffer **buf) |
| { |
| pool_free(pool_head_buffer, *buf); |
| } |
| |
| /* Releases buffer *buf if allocated. */ |
| static inline void b_drop(struct buffer **buf) |
| { |
| if (!(*buf)->size) |
| return; |
| __b_drop(buf); |
| } |
| |
| /* Releases buffer *buf if allocated, and replaces it with &buf_empty. */ |
| static inline void b_free(struct buffer **buf) |
| { |
| b_drop(buf); |
| *buf = &buf_empty; |
| } |
| |
| /* Ensures that <buf> is allocated. If an allocation is needed, it ensures that |
| * there are still at least <margin> buffers available in the pool after this |
| * allocation so that we don't leave the pool in a condition where a session or |
| * a response buffer could not be allocated anymore, resulting in a deadlock. |
| * This means that we sometimes need to try to allocate extra entries even if |
| * only one buffer is needed. |
| * |
| * We need to lock the pool here to be sure to have <margin> buffers available |
| * after the allocation, regardless how many threads that doing it in the same |
| * time. So, we use internal and lockless memory functions (prefixed with '__'). |
| */ |
| static inline struct buffer *b_alloc_margin(struct buffer **buf, int margin) |
| { |
| struct buffer *b; |
| |
| if ((*buf)->size) |
| return *buf; |
| |
| *buf = &buf_wanted; |
| #ifndef CONFIG_HAP_LOCKLESS_POOLS |
| HA_SPIN_LOCK(POOL_LOCK, &pool_head_buffer->lock); |
| #endif |
| |
| /* fast path */ |
| if ((pool_head_buffer->allocated - pool_head_buffer->used) > margin) { |
| b = __pool_get_first(pool_head_buffer); |
| if (likely(b)) { |
| #ifndef CONFIG_HAP_LOCKLESS_POOLS |
| HA_SPIN_UNLOCK(POOL_LOCK, &pool_head_buffer->lock); |
| #endif |
| b->size = pool_head_buffer->size - sizeof(struct buffer); |
| b_reset(b); |
| *buf = b; |
| return b; |
| } |
| } |
| |
| /* slow path, uses malloc() */ |
| b = __pool_refill_alloc(pool_head_buffer, margin); |
| |
| #ifndef CONFIG_HAP_LOCKLESS_POOLS |
| HA_SPIN_UNLOCK(POOL_LOCK, &pool_head_buffer->lock); |
| #endif |
| |
| if (b) { |
| b->size = pool_head_buffer->size - sizeof(struct buffer); |
| b_reset(b); |
| *buf = b; |
| } |
| return b; |
| } |
| |
| |
| /* Offer a buffer currently belonging to target <from> to whoever needs one. |
| * Any pointer is valid for <from>, including NULL. Its purpose is to avoid |
| * passing a buffer to oneself in case of failed allocations (e.g. need two |
| * buffers, get one, fail, release it and wake up self again). In case of |
| * normal buffer release where it is expected that the caller is not waiting |
| * for a buffer, NULL is fine. |
| */ |
| void __offer_buffer(void *from, unsigned int threshold); |
| |
| static inline void offer_buffers(void *from, unsigned int threshold) |
| { |
| HA_SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock); |
| if (LIST_ISEMPTY(&buffer_wq)) { |
| HA_SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock); |
| return; |
| } |
| __offer_buffer(from, threshold); |
| HA_SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock); |
| } |
| |
| /*************************************************************************/ |
| /* functions used to manipulate strings and blocks with wrapping buffers */ |
| /*************************************************************************/ |
| |
| /* returns > 0 if the first <n> characters of buffer <b> starting at offset <o> |
| * relative to the buffer's head match <ist>. (empty strings do match). It is |
| * designed to be use with reasonably small strings (ie matches a single byte |
| * per iteration). This function is usable both with input and output data. To |
| * be used like this depending on what to match : |
| * - input contents : b_isteq(b, b->o, b->i, ist); |
| * - output contents : b_isteq(b, 0, b->o, ist); |
| * Return value : |
| * >0 : the number of matching bytes |
| * =0 : not enough bytes (or matching of empty string) |
| * <0 : non-matching byte found |
| */ |
| static inline int b_isteq(const struct buffer *b, unsigned int o, size_t n, const struct ist ist) |
| { |
| struct ist r = ist; |
| const char *p; |
| const char *end = b_wrap(b); |
| |
| if (n < r.len) |
| return 0; |
| |
| p = b_peek(b, o); |
| while (r.len--) { |
| if (*p++ != *r.ptr++) |
| return -1; |
| if (unlikely(p == end)) |
| p = b->data; |
| } |
| return ist.len; |
| } |
| |
| /* "eats" string <ist> from the head of buffer <b>. Wrapping data is explicitly |
| * supported. It matches a single byte per iteration so strings should remain |
| * reasonably small. Returns : |
| * > 0 : number of bytes matched and eaten |
| * = 0 : not enough bytes (or matching an empty string) |
| * < 0 : non-matching byte found |
| */ |
| static inline int b_eat(struct buffer *b, const struct ist ist) |
| { |
| int ret = b_isteq(b, 0, b_data(b), ist); |
| if (ret > 0) |
| b_del(b, ret); |
| return ret; |
| } |
| |
| /* injects string <ist> at the tail of input buffer <b> provided that it |
| * fits. Wrapping is supported. It's designed for small strings as it only |
| * writes a single byte per iteration. Returns the number of characters copied |
| * (ist.len), 0 if it temporarily does not fit or -1 if it will never fit. It |
| * will only modify the buffer upon success. In all cases, the contents are |
| * copied prior to reporting an error, so that the destination at least |
| * contains a valid but truncated string. |
| */ |
| static inline int bi_istput(struct buffer *b, const struct ist ist) |
| { |
| const char *end = b_wrap(b); |
| struct ist r = ist; |
| char *p; |
| |
| if (r.len > (size_t)(b->size - b_data(b))) |
| return r.len < b->size ? 0 : -1; |
| |
| p = b_tail(b); |
| b->i += r.len; |
| while (r.len--) { |
| *p++ = *r.ptr++; |
| if (unlikely(p == end)) |
| p = b->data; |
| } |
| return ist.len; |
| } |
| |
| |
| /* injects string <ist> at the tail of output buffer <b> provided that it |
| * fits. Input data is assumed not to exist and will silently be overwritten. |
| * Wrapping is supported. It's designed for small strings as it only writes a |
| * single byte per iteration. Returns the number of characters copied (ist.len), |
| * 0 if it temporarily does not fit or -1 if it will never fit. It will only |
| * modify the buffer upon success. In all cases, the contents are copied prior |
| * to reporting an error, so that the destination at least contains a valid |
| * but truncated string. |
| */ |
| static inline int bo_istput(struct buffer *b, const struct ist ist) |
| { |
| const char *end = b_wrap(b); |
| struct ist r = ist; |
| char *p; |
| |
| if (r.len > (size_t)(b->size - b_data(b))) |
| return r.len < b->size ? 0 : -1; |
| |
| p = b_tail(b); |
| b->p = b_peek(b, b->o + r.len); |
| b->o += r.len; |
| while (r.len--) { |
| *p++ = *r.ptr++; |
| if (unlikely(p == end)) |
| p = b->data; |
| } |
| return ist.len; |
| } |
| |
| |
| #endif /* _COMMON_BUFFER_H */ |
| |
| /* |
| * Local variables: |
| * c-indent-level: 8 |
| * c-basic-offset: 8 |
| * End: |
| */ |