diff options
Diffstat (limited to 'lib/curl_content_encoding.c')
| -rw-r--r-- | lib/curl_content_encoding.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/lib/curl_content_encoding.c b/lib/curl_content_encoding.c new file mode 100644 index 000000000..6f4d1428a --- /dev/null +++ b/lib/curl_content_encoding.c @@ -0,0 +1,435 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 1998 - 2011, 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 http://curl.haxx.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" + +#ifdef HAVE_LIBZ + +#include "curl_urldata.h" +#include <curl/curl.h> +#include "curl_sendf.h" +#include "curl_content_encoding.h" +#include "curl_memory.h" + +#include "curl_memdebug.h" + +/* 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 DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */ + +#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 */ + +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 SessionHandle *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(z_stream *z, zlibInitState *zlib_init, CURLcode result) +{ + inflateEnd(z); + *zlib_init = ZLIB_UNINIT; + return result; +} + +static CURLcode +inflate_stream(struct connectdata *conn, + struct SingleRequest *k) +{ + int allow_restart = 1; + z_stream *z = &k->z; /* zlib state structure */ + uInt nread = z->avail_in; + Bytef *orig_in = z->next_in; + int status; /* zlib status */ + CURLcode result = CURLE_OK; /* Curl_client_write status */ + char *decomp; /* Put the decompressed data here. */ + + /* 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(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); + } + + /* because the buffer size is fixed, iteratively decompress and transfer to + the client via client_write. */ + for(;;) { + /* (re)set buffer for decompressed output for every iteration */ + z->next_out = (Bytef *)decomp; + z->avail_out = DSIZ; + + status = inflate(z, Z_SYNC_FLUSH); + if(status == Z_OK || status == Z_STREAM_END) { + allow_restart = 0; + if((DSIZ - z->avail_out) && (!k->ignorebody)) { + result = Curl_client_write(conn, CLIENTWRITE_BODY, decomp, + DSIZ - z->avail_out); + /* if !CURLE_OK, clean up, return */ + if(result) { + free(decomp); + return exit_zlib(z, &k->zlib_init, result); + } + } + + /* Done? clean up, return */ + if(status == Z_STREAM_END) { + free(decomp); + if(inflateEnd(z) == Z_OK) + return exit_zlib(z, &k->zlib_init, result); + else + return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); + } + + /* Done with these bytes, exit */ + + /* status is always Z_OK at this point! */ + if(z->avail_in == 0) { + free(decomp); + return result; + } + } + else if(allow_restart && status == Z_DATA_ERROR) { + /* some servers seem to not generate zlib headers, so this is an attempt + to fix and continue anyway */ + + (void) inflateEnd(z); /* don't care about the return code */ + if(inflateInit2(z, -MAX_WBITS) != Z_OK) { + free(decomp); + return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); + } + z->next_in = orig_in; + z->avail_in = nread; + allow_restart = 0; + continue; + } + else { /* Error; exit loop, handle below */ + free(decomp); + return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); + } + } + /* Will never get here */ +} + +CURLcode +Curl_unencode_deflate_write(struct connectdata *conn, + struct SingleRequest *k, + ssize_t nread) +{ + z_stream *z = &k->z; /* zlib state structure */ + + /* Initialize zlib? */ + if(k->zlib_init == ZLIB_UNINIT) { + memset(z, 0, sizeof(z_stream)); + z->zalloc = (alloc_func)zalloc_cb; + z->zfree = (free_func)zfree_cb; + + if(inflateInit(z) != Z_OK) + return process_zlib_error(conn, z); + k->zlib_init = ZLIB_INIT; + } + + /* Set the compressed input when this function is called */ + z->next_in = (Bytef *)k->str; + z->avail_in = (uInt)nread; + + /* Now uncompress the data */ + return inflate_stream(conn, k); +} + +#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 + +CURLcode +Curl_unencode_gzip_write(struct connectdata *conn, + struct SingleRequest *k, + ssize_t nread) +{ + z_stream *z = &k->z; /* zlib state structure */ + + /* Initialize zlib? */ + if(k->zlib_init == ZLIB_UNINIT) { + memset(z, 0, sizeof(z_stream)); + 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); + } + k->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */ + } + else { + /* we must parse the gzip header ourselves */ + if(inflateInit2(z, -MAX_WBITS) != Z_OK) { + return process_zlib_error(conn, z); + } + k->zlib_init = ZLIB_INIT; /* Initial call state */ + } + } + + if(k->zlib_init == ZLIB_INIT_GZIP) { + /* Let zlib handle the gzip decompression entirely */ + z->next_in = (Bytef *)k->str; + z->avail_in = (uInt)nread; + /* Now uncompress the data */ + return inflate_stream(conn, k); + } + +#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(z, &k->zlib_init, CURLE_FUNCTION_NOT_FOUND); + +#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 (k->zlib_init) { + /* Skip over gzip header? */ + case ZLIB_INIT: + { + /* Initial call state */ + ssize_t hlen; + + switch (check_gzip_header((unsigned char *)k->str, nread, &hlen)) { + case GZIP_OK: + z->next_in = (Bytef *)k->str + hlen; + z->avail_in = (uInt)(nread - hlen); + k->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)nread; + z->next_in = malloc(z->avail_in); + if(z->next_in == NULL) { + return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); + } + memcpy(z->next_in, k->str, z->avail_in); + k->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(z, &k->zlib_init, process_zlib_error(conn, z)); + } + + } + break; + + case ZLIB_GZIP_HEADER: + { + /* Need more gzip header data state */ + ssize_t hlen; + unsigned char *oldblock = z->next_in; + + z->avail_in += (uInt)nread; + z->next_in = realloc(z->next_in, z->avail_in); + if(z->next_in == NULL) { + free(oldblock); + return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); + } + /* Append the new block of data to the previous one */ + memcpy(z->next_in + z->avail_in - nread, k->str, nread); + + 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 *)k->str + hlen + nread - z->avail_in; + z->avail_in = (uInt)(z->avail_in - hlen); + k->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: + free(z->next_in); + return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); + } + + } + break; + + case ZLIB_GZIP_INFLATING: + default: + /* Inflating stream state */ + z->next_in = (Bytef *)k->str; + z->avail_in = (uInt)nread; + 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, k); +#endif +} + +void Curl_unencode_cleanup(struct connectdata *conn) +{ + struct SessionHandle *data = conn->data; + struct SingleRequest *k = &data->req; + z_stream *z = &k->z; + if(k->zlib_init != ZLIB_UNINIT) + (void) exit_zlib(z, &k->zlib_init, CURLE_OK); +} + +#endif /* HAVE_LIBZ */ |