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6ee57c8bdd
curl/lib/content_encoding.c
Daniel Stenberg 4d2f800677
curl.se: new home 
Closes #6172
2020-11-04 23:59:47 +01:00

1115 lines
30 KiB
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "curl_setup.h"
#include "urldata.h"
#include <curl/curl.h>
#include <stddef.h>
#ifdef HAVE_ZLIB_H
#include <zlib.h>
#endif
#ifdef HAVE_BROTLI
#include <brotli/decode.h>
#endif
#ifdef HAVE_ZSTD
#include <zstd.h>
#endif
#include "sendf.h"
#include "http.h"
#include "content_encoding.h"
#include "strdup.h"
#include "strcase.h"
#include "curl_memory.h"
#include "memdebug.h"
#define CONTENT_ENCODING_DEFAULT "identity"
#ifndef CURL_DISABLE_HTTP
#define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */
#ifdef HAVE_LIBZ
/* Comment this out if zlib is always going to be at least ver. 1.2.0.4
(doing so will reduce code size slightly). */
#define OLD_ZLIB_SUPPORT 1
#define GZIP_MAGIC_0 0x1f
#define GZIP_MAGIC_1 0x8b
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define RESERVED 0xE0 /* bits 5..7: reserved */
typedef enum {
ZLIB_UNINIT, /* uninitialized */
ZLIB_INIT, /* initialized */
ZLIB_INFLATING, /* inflating started. */
ZLIB_EXTERNAL_TRAILER, /* reading external trailer */
ZLIB_GZIP_HEADER, /* reading gzip header */
ZLIB_GZIP_INFLATING, /* inflating gzip stream */
ZLIB_INIT_GZIP /* initialized in transparent gzip mode */
} zlibInitState;
/* Writer parameters. */
struct zlib_params {
zlibInitState zlib_init; /* zlib init state */
uInt trailerlen; /* Remaining trailer byte count. */
z_stream z; /* State structure for zlib. */
};
static voidpf
zalloc_cb(voidpf opaque, unsigned int items, unsigned int size)
{
(void) opaque;
/* not a typo, keep it calloc() */
return (voidpf) calloc(items, size);
}
static void
zfree_cb(voidpf opaque, voidpf ptr)
{
(void) opaque;
free(ptr);
}
static CURLcode
process_zlib_error(struct connectdata *conn, z_stream *z)
{
struct Curl_easy *data = conn->data;
if(z->msg)
failf(data, "Error while processing content unencoding: %s",
z->msg);
else
failf(data, "Error while processing content unencoding: "
"Unknown failure within decompression software.");
return CURLE_BAD_CONTENT_ENCODING;
}
static CURLcode
exit_zlib(struct connectdata *conn,
z_stream *z, zlibInitState *zlib_init, CURLcode result)
{
if(*zlib_init == ZLIB_GZIP_HEADER)
Curl_safefree(z->next_in);
if(*zlib_init != ZLIB_UNINIT) {
if(inflateEnd(z) != Z_OK && result == CURLE_OK)
result = process_zlib_error(conn, z);
*zlib_init = ZLIB_UNINIT;
}
return result;
}
static CURLcode process_trailer(struct connectdata *conn,
struct zlib_params *zp)
{
z_stream *z = &zp->z;
CURLcode result = CURLE_OK;
uInt len = z->avail_in < zp->trailerlen? z->avail_in: zp->trailerlen;
/* Consume expected trailer bytes. Terminate stream if exhausted.
Issue an error if unexpected bytes follow. */
zp->trailerlen -= len;
z->avail_in -= len;
z->next_in += len;
if(z->avail_in)
result = CURLE_WRITE_ERROR;
if(result || !zp->trailerlen)
result = exit_zlib(conn, z, &zp->zlib_init, result);
else {
/* Only occurs for gzip with zlib < 1.2.0.4 or raw deflate. */
zp->zlib_init = ZLIB_EXTERNAL_TRAILER;
}
return result;
}
static CURLcode inflate_stream(struct connectdata *conn,
struct contenc_writer *writer,
zlibInitState started)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
uInt nread = z->avail_in;
Bytef *orig_in = z->next_in;
bool done = FALSE;
CURLcode result = CURLE_OK; /* Curl_client_write status */
char *decomp; /* Put the decompressed data here. */
/* Check state. */
if(zp->zlib_init != ZLIB_INIT &&
zp->zlib_init != ZLIB_INFLATING &&
zp->zlib_init != ZLIB_INIT_GZIP &&
zp->zlib_init != ZLIB_GZIP_INFLATING)
return exit_zlib(conn, z, &zp->zlib_init, CURLE_WRITE_ERROR);
/* Dynamically allocate a buffer for decompression because it's uncommonly
large to hold on the stack */
decomp = malloc(DSIZ);
if(decomp == NULL)
return exit_zlib(conn, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
/* because the buffer size is fixed, iteratively decompress and transfer to
the client via downstream_write function. */
while(!done) {
int status; /* zlib status */
done = TRUE;
/* (re)set buffer for decompressed output for every iteration */
z->next_out = (Bytef *) decomp;
z->avail_out = DSIZ;
#ifdef Z_BLOCK
/* Z_BLOCK is only available in zlib ver. >= 1.2.0.5 */
status = inflate(z, Z_BLOCK);
#else
/* fallback for zlib ver. < 1.2.0.5 */
status = inflate(z, Z_SYNC_FLUSH);
#endif
/* Flush output data if some. */
if(z->avail_out != DSIZ) {
if(status == Z_OK || status == Z_STREAM_END) {
zp->zlib_init = started; /* Data started. */
result = Curl_unencode_write(conn, writer->downstream, decomp,
DSIZ - z->avail_out);
if(result) {
exit_zlib(conn, z, &zp->zlib_init, result);
break;
}
}
}
/* Dispatch by inflate() status. */
switch(status) {
case Z_OK:
/* Always loop: there may be unflushed latched data in zlib state. */
done = FALSE;
break;
case Z_BUF_ERROR:
/* No more data to flush: just exit loop. */
break;
case Z_STREAM_END:
result = process_trailer(conn, zp);
break;
case Z_DATA_ERROR:
/* some servers seem to not generate zlib headers, so this is an attempt
to fix and continue anyway */
if(zp->zlib_init == ZLIB_INIT) {
/* Do not use inflateReset2(): only available since zlib 1.2.3.4. */
(void) inflateEnd(z); /* don't care about the return code */
if(inflateInit2(z, -MAX_WBITS) == Z_OK) {
z->next_in = orig_in;
z->avail_in = nread;
zp->zlib_init = ZLIB_INFLATING;
zp->trailerlen = 4; /* Tolerate up to 4 unknown trailer bytes. */
done = FALSE;
break;
}
zp->zlib_init = ZLIB_UNINIT; /* inflateEnd() already called. */
}
/* FALLTHROUGH */
default:
result = exit_zlib(conn, z, &zp->zlib_init, process_zlib_error(conn, z));
break;
}
}
free(decomp);
/* We're about to leave this call so the `nread' data bytes won't be seen
again. If we are in a state that would wrongly allow restart in raw mode
at the next call, assume output has already started. */
if(nread && zp->zlib_init == ZLIB_INIT)
zp->zlib_init = started; /* Cannot restart anymore. */
return result;
}
/* Deflate handler. */
static CURLcode deflate_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
if(!writer->downstream)
return CURLE_WRITE_ERROR;
/* Initialize zlib */
z->zalloc = (alloc_func) zalloc_cb;
z->zfree = (free_func) zfree_cb;
if(inflateInit(z) != Z_OK)
return process_zlib_error(conn, z);
zp->zlib_init = ZLIB_INIT;
return CURLE_OK;
}
static CURLcode deflate_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
/* Set the compressed input when this function is called */
z->next_in = (Bytef *) buf;
z->avail_in = (uInt) nbytes;
if(zp->zlib_init == ZLIB_EXTERNAL_TRAILER)
return process_trailer(conn, zp);
/* Now uncompress the data */
return inflate_stream(conn, writer, ZLIB_INFLATING);
}
static void deflate_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
exit_zlib(conn, z, &zp->zlib_init, CURLE_OK);
}
static const struct content_encoding deflate_encoding = {
"deflate",
NULL,
deflate_init_writer,
deflate_unencode_write,
deflate_close_writer,
sizeof(struct zlib_params)
};
/* Gzip handler. */
static CURLcode gzip_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
if(!writer->downstream)
return CURLE_WRITE_ERROR;
/* Initialize zlib */
z->zalloc = (alloc_func) zalloc_cb;
z->zfree = (free_func) zfree_cb;
if(strcmp(zlibVersion(), "1.2.0.4") >= 0) {
/* zlib ver. >= 1.2.0.4 supports transparent gzip decompressing */
if(inflateInit2(z, MAX_WBITS + 32) != Z_OK) {
return process_zlib_error(conn, z);
}
zp->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */
}
else {
/* we must parse the gzip header and trailer ourselves */
if(inflateInit2(z, -MAX_WBITS) != Z_OK) {
return process_zlib_error(conn, z);
}
zp->trailerlen = 8; /* A CRC-32 and a 32-bit input size (RFC 1952, 2.2) */
zp->zlib_init = ZLIB_INIT; /* Initial call state */
}
return CURLE_OK;
}
#ifdef OLD_ZLIB_SUPPORT
/* Skip over the gzip header */
static enum {
GZIP_OK,
GZIP_BAD,
GZIP_UNDERFLOW
} check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen)
{
int method, flags;
const ssize_t totallen = len;
/* The shortest header is 10 bytes */
if(len < 10)
return GZIP_UNDERFLOW;
if((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1))
return GZIP_BAD;
method = data[2];
flags = data[3];
if(method != Z_DEFLATED || (flags & RESERVED) != 0) {
/* Can't handle this compression method or unknown flag */
return GZIP_BAD;
}
/* Skip over time, xflags, OS code and all previous bytes */
len -= 10;
data += 10;
if(flags & EXTRA_FIELD) {
ssize_t extra_len;
if(len < 2)
return GZIP_UNDERFLOW;
extra_len = (data[1] << 8) | data[0];
if(len < (extra_len + 2))
return GZIP_UNDERFLOW;
len -= (extra_len + 2);
data += (extra_len + 2);
}
if(flags & ORIG_NAME) {
/* Skip over NUL-terminated file name */
while(len && *data) {
--len;
++data;
}
if(!len || *data)
return GZIP_UNDERFLOW;
/* Skip over the NUL */
--len;
++data;
}
if(flags & COMMENT) {
/* Skip over NUL-terminated comment */
while(len && *data) {
--len;
++data;
}
if(!len || *data)
return GZIP_UNDERFLOW;
/* Skip over the NUL */
--len;
}
if(flags & HEAD_CRC) {
if(len < 2)
return GZIP_UNDERFLOW;
len -= 2;
}
*headerlen = totallen - len;
return GZIP_OK;
}
#endif
static CURLcode gzip_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
if(zp->zlib_init == ZLIB_INIT_GZIP) {
/* Let zlib handle the gzip decompression entirely */
z->next_in = (Bytef *) buf;
z->avail_in = (uInt) nbytes;
/* Now uncompress the data */
return inflate_stream(conn, writer, ZLIB_INIT_GZIP);
}
#ifndef OLD_ZLIB_SUPPORT
/* Support for old zlib versions is compiled away and we are running with
an old version, so return an error. */
return exit_zlib(conn, z, &zp->zlib_init, CURLE_WRITE_ERROR);
#else
/* This next mess is to get around the potential case where there isn't
* enough data passed in to skip over the gzip header. If that happens, we
* malloc a block and copy what we have then wait for the next call. If
* there still isn't enough (this is definitely a worst-case scenario), we
* make the block bigger, copy the next part in and keep waiting.
*
* This is only required with zlib versions < 1.2.0.4 as newer versions
* can handle the gzip header themselves.
*/
switch(zp->zlib_init) {
/* Skip over gzip header? */
case ZLIB_INIT:
{
/* Initial call state */
ssize_t hlen;
switch(check_gzip_header((unsigned char *) buf, nbytes, &hlen)) {
case GZIP_OK:
z->next_in = (Bytef *) buf + hlen;
z->avail_in = (uInt) (nbytes - hlen);
zp->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */
break;
case GZIP_UNDERFLOW:
/* We need more data so we can find the end of the gzip header. It's
* possible that the memory block we malloc here will never be freed if
* the transfer abruptly aborts after this point. Since it's unlikely
* that circumstances will be right for this code path to be followed in
* the first place, and it's even more unlikely for a transfer to fail
* immediately afterwards, it should seldom be a problem.
*/
z->avail_in = (uInt) nbytes;
z->next_in = malloc(z->avail_in);
if(z->next_in == NULL) {
return exit_zlib(conn, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
}
memcpy(z->next_in, buf, z->avail_in);
zp->zlib_init = ZLIB_GZIP_HEADER; /* Need more gzip header data state */
/* We don't have any data to inflate yet */
return CURLE_OK;
case GZIP_BAD:
default:
return exit_zlib(conn, z, &zp->zlib_init, process_zlib_error(conn, z));
}
}
break;
case ZLIB_GZIP_HEADER:
{
/* Need more gzip header data state */
ssize_t hlen;
z->avail_in += (uInt) nbytes;
z->next_in = Curl_saferealloc(z->next_in, z->avail_in);
if(z->next_in == NULL) {
return exit_zlib(conn, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
}
/* Append the new block of data to the previous one */
memcpy(z->next_in + z->avail_in - nbytes, buf, nbytes);
switch(check_gzip_header(z->next_in, z->avail_in, &hlen)) {
case GZIP_OK:
/* This is the zlib stream data */
free(z->next_in);
/* Don't point into the malloced block since we just freed it */
z->next_in = (Bytef *) buf + hlen + nbytes - z->avail_in;
z->avail_in = (uInt) (z->avail_in - hlen);
zp->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */
break;
case GZIP_UNDERFLOW:
/* We still don't have any data to inflate! */
return CURLE_OK;
case GZIP_BAD:
default:
return exit_zlib(conn, z, &zp->zlib_init, process_zlib_error(conn, z));
}
}
break;
case ZLIB_EXTERNAL_TRAILER:
z->next_in = (Bytef *) buf;
z->avail_in = (uInt) nbytes;
return process_trailer(conn, zp);
case ZLIB_GZIP_INFLATING:
default:
/* Inflating stream state */
z->next_in = (Bytef *) buf;
z->avail_in = (uInt) nbytes;
break;
}
if(z->avail_in == 0) {
/* We don't have any data to inflate; wait until next time */
return CURLE_OK;
}
/* We've parsed the header, now uncompress the data */
return inflate_stream(conn, writer, ZLIB_GZIP_INFLATING);
#endif
}
static void gzip_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct zlib_params *zp = (struct zlib_params *) &writer->params;
z_stream *z = &zp->z; /* zlib state structure */
exit_zlib(conn, z, &zp->zlib_init, CURLE_OK);
}
static const struct content_encoding gzip_encoding = {
"gzip",
"x-gzip",
gzip_init_writer,
gzip_unencode_write,
gzip_close_writer,
sizeof(struct zlib_params)
};
#endif /* HAVE_LIBZ */
#ifdef HAVE_BROTLI
/* Writer parameters. */
struct brotli_params {
BrotliDecoderState *br; /* State structure for brotli. */
};
static CURLcode brotli_map_error(BrotliDecoderErrorCode be)
{
switch(be) {
case BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_NIBBLE:
case BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_META_NIBBLE:
case BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET:
case BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME:
case BROTLI_DECODER_ERROR_FORMAT_CL_SPACE:
case BROTLI_DECODER_ERROR_FORMAT_HUFFMAN_SPACE:
case BROTLI_DECODER_ERROR_FORMAT_CONTEXT_MAP_REPEAT:
case BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_1:
case BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_2:
case BROTLI_DECODER_ERROR_FORMAT_TRANSFORM:
case BROTLI_DECODER_ERROR_FORMAT_DICTIONARY:
case BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS:
case BROTLI_DECODER_ERROR_FORMAT_PADDING_1:
case BROTLI_DECODER_ERROR_FORMAT_PADDING_2:
#ifdef BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY
case BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY:
#endif
#ifdef BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET
case BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET:
#endif
case BROTLI_DECODER_ERROR_INVALID_ARGUMENTS:
return CURLE_BAD_CONTENT_ENCODING;
case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES:
case BROTLI_DECODER_ERROR_ALLOC_TREE_GROUPS:
case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MAP:
case BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_1:
case BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_2:
case BROTLI_DECODER_ERROR_ALLOC_BLOCK_TYPE_TREES:
return CURLE_OUT_OF_MEMORY;
default:
break;
}
return CURLE_WRITE_ERROR;
}
static CURLcode brotli_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct brotli_params *bp = (struct brotli_params *) &writer->params;
(void) conn;
if(!writer->downstream)
return CURLE_WRITE_ERROR;
bp->br = BrotliDecoderCreateInstance(NULL, NULL, NULL);
return bp->br? CURLE_OK: CURLE_OUT_OF_MEMORY;
}
static CURLcode brotli_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
struct brotli_params *bp = (struct brotli_params *) &writer->params;
const uint8_t *src = (const uint8_t *) buf;
char *decomp;
uint8_t *dst;
size_t dstleft;
CURLcode result = CURLE_OK;
BrotliDecoderResult r = BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT;
if(!bp->br)
return CURLE_WRITE_ERROR; /* Stream already ended. */
decomp = malloc(DSIZ);
if(!decomp)
return CURLE_OUT_OF_MEMORY;
while((nbytes || r == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT) &&
result == CURLE_OK) {
dst = (uint8_t *) decomp;
dstleft = DSIZ;
r = BrotliDecoderDecompressStream(bp->br,
&nbytes, &src, &dstleft, &dst, NULL);
result = Curl_unencode_write(conn, writer->downstream,
decomp, DSIZ - dstleft);
if(result)
break;
switch(r) {
case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT:
case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:
break;
case BROTLI_DECODER_RESULT_SUCCESS:
BrotliDecoderDestroyInstance(bp->br);
bp->br = NULL;
if(nbytes)
result = CURLE_WRITE_ERROR;
break;
default:
result = brotli_map_error(BrotliDecoderGetErrorCode(bp->br));
break;
}
}
free(decomp);
return result;
}
static void brotli_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct brotli_params *bp = (struct brotli_params *) &writer->params;
(void) conn;
if(bp->br) {
BrotliDecoderDestroyInstance(bp->br);
bp->br = NULL;
}
}
static const struct content_encoding brotli_encoding = {
"br",
NULL,
brotli_init_writer,
brotli_unencode_write,
brotli_close_writer,
sizeof(struct brotli_params)
};
#endif
#ifdef HAVE_ZSTD
/* Writer parameters. */
struct zstd_params {
ZSTD_DStream *zds; /* State structure for zstd. */
void *decomp;
};
static CURLcode zstd_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct zstd_params *zp = (struct zstd_params *)&writer->params;
(void)conn;
if(!writer->downstream)
return CURLE_WRITE_ERROR;
zp->zds = ZSTD_createDStream();
zp->decomp = NULL;
return zp->zds ? CURLE_OK : CURLE_OUT_OF_MEMORY;
}
static CURLcode zstd_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
CURLcode result = CURLE_OK;
struct zstd_params *zp = (struct zstd_params *)&writer->params;
ZSTD_inBuffer in;
ZSTD_outBuffer out;
size_t errorCode;
if(!zp->decomp) {
zp->decomp = malloc(DSIZ);
if(!zp->decomp)
return CURLE_OUT_OF_MEMORY;
}
in.pos = 0;
in.src = buf;
in.size = nbytes;
for(;;) {
out.pos = 0;
out.dst = zp->decomp;
out.size = DSIZ;
errorCode = ZSTD_decompressStream(zp->zds, &out, &in);
if(ZSTD_isError(errorCode)) {
return CURLE_BAD_CONTENT_ENCODING;
}
if(out.pos > 0) {
result = Curl_unencode_write(conn, writer->downstream,
zp->decomp, out.pos);
if(result)
break;
}
if((in.pos == nbytes) && (out.pos < out.size))
break;
}
return result;
}
static void zstd_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
struct zstd_params *zp = (struct zstd_params *)&writer->params;
(void)conn;
if(zp->decomp) {
free(zp->decomp);
zp->decomp = NULL;
}
if(zp->zds) {
ZSTD_freeDStream(zp->zds);
zp->zds = NULL;
}
}
static const struct content_encoding zstd_encoding = {
"zstd",
NULL,
zstd_init_writer,
zstd_unencode_write,
zstd_close_writer,
sizeof(struct zstd_params)
};
#endif
/* Identity handler. */
static CURLcode identity_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
(void) conn;
return writer->downstream? CURLE_OK: CURLE_WRITE_ERROR;
}
static CURLcode identity_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
return Curl_unencode_write(conn, writer->downstream, buf, nbytes);
}
static void identity_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
(void) conn;
(void) writer;
}
static const struct content_encoding identity_encoding = {
"identity",
"none",
identity_init_writer,
identity_unencode_write,
identity_close_writer,
0
};
/* supported content encodings table. */
static const struct content_encoding * const encodings[] = {
&identity_encoding,
#ifdef HAVE_LIBZ
&deflate_encoding,
&gzip_encoding,
#endif
#ifdef HAVE_BROTLI
&brotli_encoding,
#endif
#ifdef HAVE_ZSTD
&zstd_encoding,
#endif
NULL
};
/* Return a list of comma-separated names of supported encodings. */
char *Curl_all_content_encodings(void)
{
size_t len = 0;
const struct content_encoding * const *cep;
const struct content_encoding *ce;
char *ace;
for(cep = encodings; *cep; cep++) {
ce = *cep;
if(!strcasecompare(ce->name, CONTENT_ENCODING_DEFAULT))
len += strlen(ce->name) + 2;
}
if(!len)
return strdup(CONTENT_ENCODING_DEFAULT);
ace = malloc(len);
if(ace) {
char *p = ace;
for(cep = encodings; *cep; cep++) {
ce = *cep;
if(!strcasecompare(ce->name, CONTENT_ENCODING_DEFAULT)) {
strcpy(p, ce->name);
p += strlen(p);
*p++ = ',';
*p++ = ' ';
}
}
p[-2] = '\0';
}
return ace;
}
/* Real client writer: no downstream. */
static CURLcode client_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
(void) conn;
return writer->downstream? CURLE_WRITE_ERROR: CURLE_OK;
}
static CURLcode client_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
struct Curl_easy *data = conn->data;
struct SingleRequest *k = &data->req;
(void) writer;
if(!nbytes || k->ignorebody)
return CURLE_OK;
return Curl_client_write(conn, CLIENTWRITE_BODY, (char *) buf, nbytes);
}
static void client_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
(void) conn;
(void) writer;
}
static const struct content_encoding client_encoding = {
NULL,
NULL,
client_init_writer,
client_unencode_write,
client_close_writer,
0
};
/* Deferred error dummy writer. */
static CURLcode error_init_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
(void) conn;
return writer->downstream? CURLE_OK: CURLE_WRITE_ERROR;
}
static CURLcode error_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
char *all = Curl_all_content_encodings();
(void) writer;
(void) buf;
(void) nbytes;
if(!all)
return CURLE_OUT_OF_MEMORY;
failf(conn->data, "Unrecognized content encoding type. "
"libcurl understands %s content encodings.", all);
free(all);
return CURLE_BAD_CONTENT_ENCODING;
}
static void error_close_writer(struct connectdata *conn,
struct contenc_writer *writer)
{
(void) conn;
(void) writer;
}
static const struct content_encoding error_encoding = {
NULL,
NULL,
error_init_writer,
error_unencode_write,
error_close_writer,
0
};
/* Create an unencoding writer stage using the given handler. */
static struct contenc_writer *
new_unencoding_writer(struct connectdata *conn,
const struct content_encoding *handler,
struct contenc_writer *downstream)
{
size_t sz = offsetof(struct contenc_writer, params) + handler->paramsize;
struct contenc_writer *writer = (struct contenc_writer *)calloc(1, sz);
if(writer) {
writer->handler = handler;
writer->downstream = downstream;
if(handler->init_writer(conn, writer)) {
free(writer);
writer = NULL;
}
}
return writer;
}
/* Write data using an unencoding writer stack. */
CURLcode Curl_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
if(!nbytes)
return CURLE_OK;
return writer->handler->unencode_write(conn, writer, buf, nbytes);
}
/* Close and clean-up the connection's writer stack. */
void Curl_unencode_cleanup(struct connectdata *conn)
{
struct Curl_easy *data = conn->data;
struct SingleRequest *k = &data->req;
struct contenc_writer *writer = k->writer_stack;
while(writer) {
k->writer_stack = writer->downstream;
writer->handler->close_writer(conn, writer);
free(writer);
writer = k->writer_stack;
}
}
/* Find the content encoding by name. */
static const struct content_encoding *find_encoding(const char *name,
size_t len)
{
const struct content_encoding * const *cep;
for(cep = encodings; *cep; cep++) {
const struct content_encoding *ce = *cep;
if((strncasecompare(name, ce->name, len) && !ce->name[len]) ||
(ce->alias && strncasecompare(name, ce->alias, len) && !ce->alias[len]))
return ce;
}
return NULL;
}
/* Set-up the unencoding stack from the Content-Encoding header value.
* See RFC 7231 section 3.1.2.2. */
CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
const char *enclist, int maybechunked)
{
struct Curl_easy *data = conn->data;
struct SingleRequest *k = &data->req;
do {
const char *name;
size_t namelen;
/* Parse a single encoding name. */
while(ISSPACE(*enclist) || *enclist == ',')
enclist++;
name = enclist;
for(namelen = 0; *enclist && *enclist != ','; enclist++)
if(!ISSPACE(*enclist))
namelen = enclist - name + 1;
/* Special case: chunked encoding is handled at the reader level. */
if(maybechunked && namelen == 7 && strncasecompare(name, "chunked", 7)) {
k->chunk = TRUE; /* chunks coming our way. */
Curl_httpchunk_init(conn); /* init our chunky engine. */
}
else if(namelen) {
const struct content_encoding *encoding = find_encoding(name, namelen);
struct contenc_writer *writer;
if(!k->writer_stack) {
k->writer_stack = new_unencoding_writer(conn, &client_encoding, NULL);
if(!k->writer_stack)
return CURLE_OUT_OF_MEMORY;
}
if(!encoding)
encoding = &error_encoding; /* Defer error at stack use. */
/* Stack the unencoding stage. */
writer = new_unencoding_writer(conn, encoding, k->writer_stack);
if(!writer)
return CURLE_OUT_OF_MEMORY;
k->writer_stack = writer;
}
} while(*enclist);
return CURLE_OK;
}
#else
/* Stubs for builds without HTTP. */
CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
const char *enclist, int maybechunked)
{
(void) conn;
(void) enclist;
(void) maybechunked;
return CURLE_NOT_BUILT_IN;
}
CURLcode Curl_unencode_write(struct connectdata *conn,
struct contenc_writer *writer,
const char *buf, size_t nbytes)
{
(void) conn;
(void) writer;
(void) buf;
(void) nbytes;
return CURLE_NOT_BUILT_IN;
}
void Curl_unencode_cleanup(struct connectdata *conn)
{
(void) conn;
}
char *Curl_all_content_encodings(void)
{
return strdup(CONTENT_ENCODING_DEFAULT); /* Satisfy caller. */
}
#endif /* CURL_DISABLE_HTTP */
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