tor/src/lib/container/buffers.c

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2006-02-09 06:46:49 +01:00
/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
2018-06-28 23:21:15 +02:00
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
2019-01-16 18:32:32 +01:00
* Copyright (c) 2007-2019, The Tor Project, Inc. */
/* See LICENSE for licensing information */
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/**
* \file buffers.c
* \brief Implements a generic buffer interface.
*
* A buf_t is a (fairly) opaque byte-oriented FIFO that can read to or flush
* from memory, sockets, file descriptors, TLS connections, or another buf_t.
* Buffers are implemented as linked lists of memory chunks.
*
* All socket-backed and TLS-based connection_t objects have a pair of
* buffers: one for incoming data, and one for outcoming data. These are fed
* and drained from functions in connection.c, trigged by events that are
* monitored in main.c.
*
* This module only handles the buffer implementation itself. To use a buffer
* with the network, a compressor, or a TLS connection, see the other buffer_*
* modules.
**/
#define BUFFERS_PRIVATE
#include "orconfig.h"
#include <stddef.h>
#include "lib/container/buffers.h"
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#include "lib/cc/torint.h"
#include "lib/log/log.h"
#include "lib/log/util_bug.h"
#include "lib/ctime/di_ops.h"
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#include "lib/malloc/malloc.h"
#include "lib/string/printf.h"
#include "lib/time/compat_time.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
//#define PARANOIA
#ifdef PARANOIA
/** Helper: If PARANOIA is defined, assert that the buffer in local variable
* <b>buf</b> is well-formed. */
#define check() STMT_BEGIN buf_assert_ok(buf); STMT_END
#else
#define check() STMT_NIL
#endif /* defined(PARANOIA) */
/* Implementation notes:
*
* After flirting with memmove, and dallying with ring-buffers, we're finally
* getting up to speed with the 1970s and implementing buffers as a linked
* list of small chunks. Each buffer has such a list; data is removed from
* the head of the list, and added at the tail. The list is singly linked,
* and the buffer keeps a pointer to the head and the tail.
*
* Every chunk, except the tail, contains at least one byte of data. Data in
* each chunk is contiguous.
*
* When you need to treat the first N characters on a buffer as a contiguous
* string, use the buf_pullup function to make them so. Don't do this more
* than necessary.
*
* The major free Unix kernels have handled buffers like this since, like,
* forever.
*/
/* Chunk manipulation functions */
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#define CHUNK_HEADER_LEN offsetof(chunk_t, mem[0])
/* We leave this many NUL bytes at the end of the buffer. */
#ifdef DISABLE_MEMORY_SENTINELS
#define SENTINEL_LEN 0
#else
#define SENTINEL_LEN 4
#endif
/* Header size plus NUL bytes at the end */
#define CHUNK_OVERHEAD (CHUNK_HEADER_LEN + SENTINEL_LEN)
/** Return the number of bytes needed to allocate a chunk to hold
* <b>memlen</b> bytes. */
#define CHUNK_ALLOC_SIZE(memlen) (CHUNK_OVERHEAD + (memlen))
/** Return the number of usable bytes in a chunk allocated with
* malloc(<b>memlen</b>). */
#define CHUNK_SIZE_WITH_ALLOC(memlen) ((memlen) - CHUNK_OVERHEAD)
#define DEBUG_SENTINEL
#if defined(DEBUG_SENTINEL) && !defined(DISABLE_MEMORY_SENTINELS)
#define DBG_S(s) s
#else
#define DBG_S(s) (void)0
#endif
#ifdef DISABLE_MEMORY_SENTINELS
#define CHUNK_SET_SENTINEL(chunk, alloclen) STMT_NIL
#else
#define CHUNK_SET_SENTINEL(chunk, alloclen) do { \
uint8_t *a = (uint8_t*) &(chunk)->mem[(chunk)->memlen]; \
DBG_S(uint8_t *b = &((uint8_t*)(chunk))[(alloclen)-SENTINEL_LEN]); \
DBG_S(tor_assert(a == b)); \
memset(a,0,SENTINEL_LEN); \
} while (0)
#endif /* defined(DISABLE_MEMORY_SENTINELS) */
/** Move all bytes stored in <b>chunk</b> to the front of <b>chunk</b>->mem,
* to free up space at the end. */
static inline void
chunk_repack(chunk_t *chunk)
{
if (chunk->datalen && chunk->data != &chunk->mem[0]) {
memmove(chunk->mem, chunk->data, chunk->datalen);
}
chunk->data = &chunk->mem[0];
}
/** Keep track of total size of allocated chunks for consistency asserts */
static size_t total_bytes_allocated_in_chunks = 0;
static void
buf_chunk_free_unchecked(chunk_t *chunk)
{
if (!chunk)
return;
#ifdef DEBUG_CHUNK_ALLOC
tor_assert(CHUNK_ALLOC_SIZE(chunk->memlen) == chunk->DBG_alloc);
#endif
tor_assert(total_bytes_allocated_in_chunks >=
CHUNK_ALLOC_SIZE(chunk->memlen));
total_bytes_allocated_in_chunks -= CHUNK_ALLOC_SIZE(chunk->memlen);
tor_free(chunk);
}
static inline chunk_t *
chunk_new_with_alloc_size(size_t alloc)
{
chunk_t *ch;
ch = tor_malloc(alloc);
ch->next = NULL;
ch->datalen = 0;
#ifdef DEBUG_CHUNK_ALLOC
ch->DBG_alloc = alloc;
#endif
ch->memlen = CHUNK_SIZE_WITH_ALLOC(alloc);
total_bytes_allocated_in_chunks += alloc;
ch->data = &ch->mem[0];
CHUNK_SET_SENTINEL(ch, alloc);
return ch;
}
/** Expand <b>chunk</b> until it can hold <b>sz</b> bytes, and return a
* new pointer to <b>chunk</b>. Old pointers are no longer valid. */
static inline chunk_t *
chunk_grow(chunk_t *chunk, size_t sz)
{
off_t offset;
const size_t memlen_orig = chunk->memlen;
const size_t orig_alloc = CHUNK_ALLOC_SIZE(memlen_orig);
const size_t new_alloc = CHUNK_ALLOC_SIZE(sz);
tor_assert(sz > chunk->memlen);
offset = chunk->data - chunk->mem;
chunk = tor_realloc(chunk, new_alloc);
chunk->memlen = sz;
chunk->data = chunk->mem + offset;
#ifdef DEBUG_CHUNK_ALLOC
tor_assert(chunk->DBG_alloc == orig_alloc);
chunk->DBG_alloc = new_alloc;
#endif
total_bytes_allocated_in_chunks += new_alloc - orig_alloc;
CHUNK_SET_SENTINEL(chunk, new_alloc);
return chunk;
}
/** Every chunk should take up at least this many bytes. */
#define MIN_CHUNK_ALLOC 256
/** No chunk should take up more than this many bytes. */
#define MAX_CHUNK_ALLOC 65536
/** Return the allocation size we'd like to use to hold <b>target</b>
* bytes. */
size_t
buf_preferred_chunk_size(size_t target)
{
tor_assert(target <= SIZE_T_CEILING - CHUNK_OVERHEAD);
if (CHUNK_ALLOC_SIZE(target) >= MAX_CHUNK_ALLOC)
return CHUNK_ALLOC_SIZE(target);
size_t sz = MIN_CHUNK_ALLOC;
while (CHUNK_SIZE_WITH_ALLOC(sz) < target) {
sz <<= 1;
}
return sz;
}
/** Collapse data from the first N chunks from <b>buf</b> into buf->head,
* growing it as necessary, until buf->head has the first <b>bytes</b> bytes
* of data from the buffer, or until buf->head has all the data in <b>buf</b>.
*
* Set *<b>head_out</b> to point to the first byte of available data, and
* *<b>len_out</b> to the number of bytes of data available at
* *<b>head_out</b>. Note that *<b>len_out</b> may be more or less than
* <b>bytes</b>, depending on the number of bytes available.
*/
void
buf_pullup(buf_t *buf, size_t bytes, const char **head_out, size_t *len_out)
{
chunk_t *dest, *src;
size_t capacity;
if (!buf->head) {
*head_out = NULL;
*len_out = 0;
return;
}
check();
if (buf->datalen < bytes)
bytes = buf->datalen;
capacity = bytes;
if (buf->head->datalen >= bytes) {
*head_out = buf->head->data;
*len_out = buf->head->datalen;
return;
}
if (buf->head->memlen >= capacity) {
/* We don't need to grow the first chunk, but we might need to repack it.*/
size_t needed = capacity - buf->head->datalen;
if (CHUNK_REMAINING_CAPACITY(buf->head) < needed)
chunk_repack(buf->head);
tor_assert(CHUNK_REMAINING_CAPACITY(buf->head) >= needed);
} else {
chunk_t *newhead;
size_t newsize;
/* We need to grow the chunk. */
chunk_repack(buf->head);
newsize = CHUNK_SIZE_WITH_ALLOC(buf_preferred_chunk_size(capacity));
newhead = chunk_grow(buf->head, newsize);
tor_assert(newhead->memlen >= capacity);
if (newhead != buf->head) {
if (buf->tail == buf->head)
buf->tail = newhead;
buf->head = newhead;
}
}
dest = buf->head;
while (dest->datalen < bytes) {
size_t n = bytes - dest->datalen;
src = dest->next;
tor_assert(src);
if (n >= src->datalen) {
memcpy(CHUNK_WRITE_PTR(dest), src->data, src->datalen);
dest->datalen += src->datalen;
dest->next = src->next;
if (buf->tail == src)
buf->tail = dest;
buf_chunk_free_unchecked(src);
} else {
memcpy(CHUNK_WRITE_PTR(dest), src->data, n);
dest->datalen += n;
src->data += n;
src->datalen -= n;
tor_assert(dest->datalen == bytes);
}
}
check();
*head_out = buf->head->data;
*len_out = buf->head->datalen;
}
#ifdef TOR_UNIT_TESTS
/* Write sz bytes from cp into a newly allocated buffer buf.
* Returns NULL when passed a NULL cp or zero sz.
* Asserts on failure: only for use in unit tests.
* buf must be freed using buf_free(). */
buf_t *
buf_new_with_data(const char *cp, size_t sz)
{
/* Validate arguments */
if (!cp || sz <= 0) {
return NULL;
}
tor_assert(sz < SSIZE_T_CEILING);
/* Allocate a buffer */
buf_t *buf = buf_new_with_capacity(sz);
tor_assert(buf);
buf_assert_ok(buf);
tor_assert(!buf->head);
/* Allocate a chunk that is sz bytes long */
buf->head = chunk_new_with_alloc_size(CHUNK_ALLOC_SIZE(sz));
buf->tail = buf->head;
tor_assert(buf->head);
buf_assert_ok(buf);
tor_assert(buf_allocation(buf) >= sz);
/* Copy the data and size the buffers */
tor_assert(sz <= buf_slack(buf));
tor_assert(sz <= CHUNK_REMAINING_CAPACITY(buf->head));
memcpy(&buf->head->mem[0], cp, sz);
buf->datalen = sz;
buf->head->datalen = sz;
buf->head->data = &buf->head->mem[0];
buf_assert_ok(buf);
/* Make sure everything is large enough */
tor_assert(buf_allocation(buf) >= sz);
tor_assert(buf_allocation(buf) >= buf_datalen(buf) + buf_slack(buf));
/* Does the buffer implementation allocate more than the requested size?
* (for example, by rounding up). If so, these checks will fail. */
tor_assert(buf_datalen(buf) == sz);
tor_assert(buf_slack(buf) == 0);
return buf;
}
#endif /* defined(TOR_UNIT_TESTS) */
/** Remove the first <b>n</b> bytes from buf. */
void
buf_drain(buf_t *buf, size_t n)
{
tor_assert(buf->datalen >= n);
while (n) {
tor_assert(buf->head);
if (buf->head->datalen > n) {
buf->head->datalen -= n;
buf->head->data += n;
buf->datalen -= n;
return;
} else {
chunk_t *victim = buf->head;
n -= victim->datalen;
buf->datalen -= victim->datalen;
buf->head = victim->next;
if (buf->tail == victim)
buf->tail = NULL;
buf_chunk_free_unchecked(victim);
}
}
check();
}
/** Create and return a new buf with default chunk capacity <b>size</b>.
*/
buf_t *
buf_new_with_capacity(size_t size)
{
buf_t *b = buf_new();
b->default_chunk_size = buf_preferred_chunk_size(size);
return b;
}
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/** Allocate and return a new buffer with default capacity. */
buf_t *
buf_new(void)
{
buf_t *buf = tor_malloc_zero(sizeof(buf_t));
buf->magic = BUFFER_MAGIC;
buf->default_chunk_size = 4096;
return buf;
}
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size_t
buf_get_default_chunk_size(const buf_t *buf)
{
return buf->default_chunk_size;
}
/** Remove all data from <b>buf</b>. */
void
buf_clear(buf_t *buf)
{
chunk_t *chunk, *next;
buf->datalen = 0;
for (chunk = buf->head; chunk; chunk = next) {
next = chunk->next;
buf_chunk_free_unchecked(chunk);
}
buf->head = buf->tail = NULL;
}
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/** Return the number of bytes stored in <b>buf</b> */
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MOCK_IMPL(size_t,
buf_datalen, (const buf_t *buf))
{
return buf->datalen;
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}
/** Return the total length of all chunks used in <b>buf</b>. */
size_t
buf_allocation(const buf_t *buf)
{
size_t total = 0;
const chunk_t *chunk;
for (chunk = buf->head; chunk; chunk = chunk->next) {
total += CHUNK_ALLOC_SIZE(chunk->memlen);
}
return total;
}
/** Return the number of bytes that can be added to <b>buf</b> without
* performing any additional allocation. */
size_t
buf_slack(const buf_t *buf)
{
if (!buf->tail)
return 0;
else
return CHUNK_REMAINING_CAPACITY(buf->tail);
}
/** Release storage held by <b>buf</b>. */
void
buf_free_(buf_t *buf)
{
if (!buf)
return;
buf_clear(buf);
buf->magic = 0xdeadbeef;
tor_free(buf);
}
/** Return a new copy of <b>in_chunk</b> */
static chunk_t *
chunk_copy(const chunk_t *in_chunk)
{
chunk_t *newch = tor_memdup(in_chunk, CHUNK_ALLOC_SIZE(in_chunk->memlen));
total_bytes_allocated_in_chunks += CHUNK_ALLOC_SIZE(in_chunk->memlen);
#ifdef DEBUG_CHUNK_ALLOC
newch->DBG_alloc = CHUNK_ALLOC_SIZE(in_chunk->memlen);
#endif
newch->next = NULL;
if (in_chunk->data) {
off_t offset = in_chunk->data - in_chunk->mem;
newch->data = newch->mem + offset;
}
return newch;
}
/** Return a new copy of <b>buf</b> */
buf_t *
buf_copy(const buf_t *buf)
{
chunk_t *ch;
buf_t *out = buf_new();
out->default_chunk_size = buf->default_chunk_size;
for (ch = buf->head; ch; ch = ch->next) {
chunk_t *newch = chunk_copy(ch);
if (out->tail) {
out->tail->next = newch;
out->tail = newch;
} else {
out->head = out->tail = newch;
}
}
out->datalen = buf->datalen;
return out;
}
/** Append a new chunk with enough capacity to hold <b>capacity</b> bytes to
* the tail of <b>buf</b>. If <b>capped</b>, don't allocate a chunk bigger
* than MAX_CHUNK_ALLOC. */
chunk_t *
buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped)
{
chunk_t *chunk;
if (CHUNK_ALLOC_SIZE(capacity) < buf->default_chunk_size) {
chunk = chunk_new_with_alloc_size(buf->default_chunk_size);
} else if (capped && CHUNK_ALLOC_SIZE(capacity) > MAX_CHUNK_ALLOC) {
chunk = chunk_new_with_alloc_size(MAX_CHUNK_ALLOC);
} else {
chunk = chunk_new_with_alloc_size(buf_preferred_chunk_size(capacity));
}
chunk->inserted_time = monotime_coarse_get_stamp();
if (buf->tail) {
tor_assert(buf->head);
buf->tail->next = chunk;
buf->tail = chunk;
} else {
tor_assert(!buf->head);
buf->head = buf->tail = chunk;
}
check();
return chunk;
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}
/** Return the age of the oldest chunk in the buffer <b>buf</b>, in
* timestamp units. Requires the current monotonic timestamp as its
* input <b>now</b>.
*/
uint32_t
buf_get_oldest_chunk_timestamp(const buf_t *buf, uint32_t now)
{
if (buf->head) {
return now - buf->head->inserted_time;
} else {
return 0;
}
}
size_t
buf_get_total_allocation(void)
{
return total_bytes_allocated_in_chunks;
}
/** Append <b>string_len</b> bytes from <b>string</b> to the end of
* <b>buf</b>.
*
* Return the new length of the buffer on success, -1 on failure.
*/
int
buf_add(buf_t *buf, const char *string, size_t string_len)
{
if (!string_len)
return (int)buf->datalen;
check();
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if (BUG(buf->datalen >= INT_MAX))
return -1;
if (BUG(buf->datalen >= INT_MAX - string_len))
return -1;
while (string_len) {
size_t copy;
if (!buf->tail || !CHUNK_REMAINING_CAPACITY(buf->tail))
buf_add_chunk_with_capacity(buf, string_len, 1);
copy = CHUNK_REMAINING_CAPACITY(buf->tail);
if (copy > string_len)
copy = string_len;
memcpy(CHUNK_WRITE_PTR(buf->tail), string, copy);
string_len -= copy;
string += copy;
buf->datalen += copy;
buf->tail->datalen += copy;
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}
check();
tor_assert(buf->datalen < INT_MAX);
return (int)buf->datalen;
}
/** Add a nul-terminated <b>string</b> to <b>buf</b>, not including the
* terminating NUL. */
void
buf_add_string(buf_t *buf, const char *string)
{
buf_add(buf, string, strlen(string));
}
/** As tor_snprintf, but write the results into a buf_t */
void
buf_add_printf(buf_t *buf, const char *format, ...)
{
va_list ap;
va_start(ap,format);
buf_add_vprintf(buf, format, ap);
va_end(ap);
}
/** As tor_vsnprintf, but write the results into a buf_t. */
void
buf_add_vprintf(buf_t *buf, const char *format, va_list args)
{
/* XXXX Faster implementations are easy enough, but let's optimize later */
char *tmp;
tor_vasprintf(&tmp, format, args);
buf_add(buf, tmp, strlen(tmp));
tor_free(tmp);
}
/** Return a heap-allocated string containing the contents of <b>buf</b>, plus
* a NUL byte. If <b>sz_out</b> is provided, set *<b>sz_out</b> to the length
* of the returned string, not including the terminating NUL. */
char *
buf_extract(buf_t *buf, size_t *sz_out)
{
tor_assert(buf);
size_t sz = buf_datalen(buf);
char *result;
result = tor_malloc(sz+1);
buf_peek(buf, result, sz);
result[sz] = 0;
if (sz_out)
*sz_out = sz;
return result;
}
/** Helper: copy the first <b>string_len</b> bytes from <b>buf</b>
* onto <b>string</b>.
*/
void
buf_peek(const buf_t *buf, char *string, size_t string_len)
{
chunk_t *chunk;
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tor_assert(string);
/* make sure we don't ask for too much */
tor_assert(string_len <= buf->datalen);
/* buf_assert_ok(buf); */
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chunk = buf->head;
while (string_len) {
size_t copy = string_len;
tor_assert(chunk);
if (chunk->datalen < copy)
copy = chunk->datalen;
memcpy(string, chunk->data, copy);
string_len -= copy;
string += copy;
chunk = chunk->next;
}
}
/** Remove <b>string_len</b> bytes from the front of <b>buf</b>, and store
* them into <b>string</b>. Return the new buffer size. <b>string_len</b>
* must be \<= the number of bytes on the buffer.
*/
int
buf_get_bytes(buf_t *buf, char *string, size_t string_len)
{
/* There must be string_len bytes in buf; write them onto string,
* then memmove buf back (that is, remove them from buf).
*
* Return the number of bytes still on the buffer. */
check();
buf_peek(buf, string, string_len);
buf_drain(buf, string_len);
check();
tor_assert(buf->datalen < INT_MAX);
return (int)buf->datalen;
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}
/** Move up to *<b>buf_flushlen</b> bytes from <b>buf_in</b> to
* <b>buf_out</b>, and modify *<b>buf_flushlen</b> appropriately.
* Return the number of bytes actually copied.
*/
int
buf_move_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen)
{
/* We can do way better here, but this doesn't turn up in any profiles. */
char b[4096];
size_t cp, len;
if (BUG(buf_out->datalen >= INT_MAX))
return -1;
if (BUG(buf_out->datalen >= INT_MAX - *buf_flushlen))
return -1;
len = *buf_flushlen;
if (len > buf_in->datalen)
len = buf_in->datalen;
cp = len; /* Remember the number of bytes we intend to copy. */
tor_assert(cp < INT_MAX);
while (len) {
/* This isn't the most efficient implementation one could imagine, since
* it does two copies instead of 1, but I kinda doubt that this will be
* critical path. */
size_t n = len > sizeof(b) ? sizeof(b) : len;
buf_get_bytes(buf_in, b, n);
buf_add(buf_out, b, n);
len -= n;
}
*buf_flushlen -= cp;
return (int)cp;
}
/** Moves all data from <b>buf_in</b> to <b>buf_out</b>, without copying.
*/
void
buf_move_all(buf_t *buf_out, buf_t *buf_in)
{
tor_assert(buf_out);
if (!buf_in)
return;
if (buf_out->head == NULL) {
buf_out->head = buf_in->head;
buf_out->tail = buf_in->tail;
} else {
buf_out->tail->next = buf_in->head;
buf_out->tail = buf_in->tail;
}
buf_out->datalen += buf_in->datalen;
buf_in->head = buf_in->tail = NULL;
buf_in->datalen = 0;
}
/** Internal structure: represents a position in a buffer. */
typedef struct buf_pos_t {
const chunk_t *chunk; /**< Which chunk are we pointing to? */
int pos;/**< Which character inside the chunk's data are we pointing to? */
size_t chunk_pos; /**< Total length of all previous chunks. */
} buf_pos_t;
/** Initialize <b>out</b> to point to the first character of <b>buf</b>.*/
static void
buf_pos_init(const buf_t *buf, buf_pos_t *out)
{
out->chunk = buf->head;
out->pos = 0;
out->chunk_pos = 0;
}
/** Advance <b>out</b> to the first appearance of <b>ch</b> at the current
* position of <b>out</b>, or later. Return -1 if no instances are found;
* otherwise returns the absolute position of the character. */
static off_t
buf_find_pos_of_char(char ch, buf_pos_t *out)
{
const chunk_t *chunk;
int pos;
tor_assert(out);
if (out->chunk) {
if (out->chunk->datalen) {
tor_assert(out->pos < (off_t)out->chunk->datalen);
} else {
tor_assert(out->pos == 0);
}
}
pos = out->pos;
for (chunk = out->chunk; chunk; chunk = chunk->next) {
char *cp = memchr(chunk->data+pos, ch, chunk->datalen - pos);
if (cp) {
out->chunk = chunk;
tor_assert(cp - chunk->data < INT_MAX);
out->pos = (int)(cp - chunk->data);
return out->chunk_pos + out->pos;
} else {
out->chunk_pos += chunk->datalen;
pos = 0;
}
}
return -1;
}
/** Advance <b>pos</b> by a single character, if there are any more characters
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* in the buffer. Returns 0 on success, -1 on failure. */
static inline int
buf_pos_inc(buf_pos_t *pos)
{
++pos->pos;
if (pos->pos == (off_t)pos->chunk->datalen) {
if (!pos->chunk->next)
return -1;
pos->chunk_pos += pos->chunk->datalen;
pos->chunk = pos->chunk->next;
pos->pos = 0;
}
return 0;
}
/** Return true iff the <b>n</b>-character string in <b>s</b> appears
* (verbatim) at <b>pos</b>. */
static int
buf_matches_at_pos(const buf_pos_t *pos, const char *s, size_t n)
{
buf_pos_t p;
if (!n)
return 1;
memcpy(&p, pos, sizeof(p));
while (1) {
char ch = p.chunk->data[p.pos];
if (ch != *s)
return 0;
++s;
/* If we're out of characters that don't match, we match. Check this
* _before_ we test incrementing pos, in case we're at the end of the
* string. */
if (--n == 0)
return 1;
if (buf_pos_inc(&p)<0)
return 0;
}
}
/** Return the first position in <b>buf</b> at which the <b>n</b>-character
* string <b>s</b> occurs, or -1 if it does not occur. */
int
buf_find_string_offset(const buf_t *buf, const char *s, size_t n)
{
buf_pos_t pos;
buf_pos_init(buf, &pos);
while (buf_find_pos_of_char(*s, &pos) >= 0) {
if (buf_matches_at_pos(&pos, s, n)) {
tor_assert(pos.chunk_pos + pos.pos < INT_MAX);
return (int)(pos.chunk_pos + pos.pos);
} else {
if (buf_pos_inc(&pos)<0)
return -1;
}
}
return -1;
}
/** Return 1 iff <b>buf</b> starts with <b>cmd</b>. <b>cmd</b> must be a null
* terminated string, of no more than PEEK_BUF_STARTSWITH_MAX bytes. */
int
buf_peek_startswith(const buf_t *buf, const char *cmd)
{
char tmp[PEEK_BUF_STARTSWITH_MAX];
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size_t clen = strlen(cmd);
if (clen == 0)
return 1;
if (BUG(clen > sizeof(tmp)))
return 0;
if (buf->datalen < clen)
return 0;
buf_peek(buf, tmp, clen);
return fast_memeq(tmp, cmd, clen);
}
/** Return the index within <b>buf</b> at which <b>ch</b> first appears,
* or -1 if <b>ch</b> does not appear on buf. */
static off_t
buf_find_offset_of_char(buf_t *buf, char ch)
{
chunk_t *chunk;
off_t offset = 0;
for (chunk = buf->head; chunk; chunk = chunk->next) {
char *cp = memchr(chunk->data, ch, chunk->datalen);
if (cp)
return offset + (cp - chunk->data);
else
offset += chunk->datalen;
}
return -1;
}
/** Try to read a single LF-terminated line from <b>buf</b>, and write it
* (including the LF), NUL-terminated, into the *<b>data_len</b> byte buffer
* at <b>data_out</b>. Set *<b>data_len</b> to the number of bytes in the
* line, not counting the terminating NUL. Return 1 if we read a whole line,
* return 0 if we don't have a whole line yet, and return -1 if the line
* length exceeds *<b>data_len</b>.
*/
int
buf_get_line(buf_t *buf, char *data_out, size_t *data_len)
{
size_t sz;
off_t offset;
if (!buf->head)
return 0;
offset = buf_find_offset_of_char(buf, '\n');
if (offset < 0)
return 0;
sz = (size_t) offset;
if (sz+2 > *data_len) {
*data_len = sz + 2;
return -1;
}
buf_get_bytes(buf, data_out, sz+1);
data_out[sz+1] = '\0';
*data_len = sz+1;
return 1;
}
/** Set *<b>output</b> to contain a copy of the data in *<b>input</b> */
int
buf_set_to_copy(buf_t **output,
const buf_t *input)
{
if (*output)
buf_free(*output);
*output = buf_copy(input);
return 0;
}
/** Log an error and exit if <b>buf</b> is corrupted.
*/
void
buf_assert_ok(buf_t *buf)
{
tor_assert(buf);
tor_assert(buf->magic == BUFFER_MAGIC);
if (! buf->head) {
tor_assert(!buf->tail);
tor_assert(buf->datalen == 0);
} else {
chunk_t *ch;
size_t total = 0;
tor_assert(buf->tail);
for (ch = buf->head; ch; ch = ch->next) {
total += ch->datalen;
tor_assert(ch->datalen <= ch->memlen);
tor_assert(ch->data >= &ch->mem[0]);
tor_assert(ch->data <= &ch->mem[0]+ch->memlen);
if (ch->data == &ch->mem[0]+ch->memlen) {
/* LCOV_EXCL_START */
static int warned = 0;
if (! warned) {
log_warn(LD_BUG, "Invariant violation in buf.c related to #15083");
warned = 1;
}
/* LCOV_EXCL_STOP */
}
tor_assert(ch->data+ch->datalen <= &ch->mem[0] + ch->memlen);
if (!ch->next)
tor_assert(ch == buf->tail);
}
tor_assert(buf->datalen == total);
}
}