/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2004, 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. * * $Id$ ***************************************************************************/ #include "setup.h" #ifdef HAVE_LIBZ #include <stdlib.h> #include <string.h> #include "urldata.h" #include <curl/curl.h> #include "sendf.h" #include "content_encoding.h" #include "curl_memory.h" #include "memdebug.h" #define DSIZ 0x10000 /* 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 CURLcode process_zlib_error(struct SessionHandle *data, z_stream *z) { if (z->msg) failf (data, "Error while processing content unencoding.\n%s", z->msg); else failf (data, "Error while processing content unencoding.\n" "Unknown failure within decompression software."); return CURLE_BAD_CONTENT_ENCODING; } static CURLcode exit_zlib(z_stream *z, bool *zlib_init, CURLcode result) { inflateEnd(z); *zlib_init = 0; return result; } CURLcode Curl_unencode_deflate_write(struct SessionHandle *data, struct Curl_transfer_keeper *k, ssize_t nread) { int status; /* zlib status */ CURLcode result = CURLE_OK; /* Curl_client_write status */ char decomp[DSIZ]; /* Put the decompressed data here. */ z_stream *z = &k->z; /* zlib state structure */ /* Initialize zlib? */ if (!k->zlib_init) { z->zalloc = (alloc_func)Z_NULL; z->zfree = (free_func)Z_NULL; z->opaque = 0; z->next_in = NULL; z->avail_in = 0; if (inflateInit(z) != Z_OK) return process_zlib_error(data, z); k->zlib_init = 1; } /* Set the compressed input when this function is called */ z->next_in = (Bytef *)k->str; z->avail_in = (uInt)nread; /* 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[0]; z->avail_out = DSIZ; status = inflate(z, Z_SYNC_FLUSH); if (status == Z_OK || status == Z_STREAM_END) { if (DSIZ - z->avail_out) { result = Curl_client_write(data, CLIENTWRITE_BODY, decomp, DSIZ - z->avail_out); /* if !CURLE_OK, clean up, return */ if (result) return exit_zlib(z, &k->zlib_init, result); } /* Done?; clean up, return */ if (status == Z_STREAM_END) { if (inflateEnd(z) == Z_OK) return exit_zlib(z, &k->zlib_init, result); else return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z)); } /* Done with these bytes, exit */ if (status == Z_OK && z->avail_in == 0 && z->avail_out > 0) return result; } else { /* Error; exit loop, handle below */ return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z)); } } } /* 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); } 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; ++data; } if (flags & HEAD_CRC) { if (len < 2) return GZIP_UNDERFLOW; len -= 2; data += 2; } *headerlen = totallen - len; return GZIP_OK; } CURLcode Curl_unencode_gzip_write(struct SessionHandle *data, struct Curl_transfer_keeper *k, ssize_t nread) { int status; /* zlib status */ CURLcode result = CURLE_OK; /* Curl_client_write status */ char decomp[DSIZ]; /* Put the decompressed data here. */ z_stream *z = &k->z; /* zlib state structure */ /* Initialize zlib? */ if (!k->zlib_init) { z->zalloc = (alloc_func)Z_NULL; z->zfree = (free_func)Z_NULL; z->opaque = 0; z->next_in = NULL; z->avail_in = 0; if (inflateInit2(z, -MAX_WBITS) != Z_OK) return process_zlib_error(data, z); k->zlib_init = 1; /* Initial call state */ } /* 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. */ /* Skip over gzip header? */ if (k->zlib_init == 1) { /* 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 = 3; /* 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 = 2; /* 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(data, z)); } } else if (k->zlib_init == 2) { /* Need more gzip header data state */ ssize_t hlen; unsigned char *oldblock = z->next_in; z->avail_in += 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 = 3; /* 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(data, z)); } } else { /* Inflating stream state */ z->next_in = (Bytef *)k->str; z->avail_in = (uInt)nread; } if (z->avail_in == 0) { /* We don't have any data to inflate; wait until next time */ return CURLE_OK; } /* 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[0]; z->avail_out = DSIZ; status = inflate(z, Z_SYNC_FLUSH); if (status == Z_OK || status == Z_STREAM_END) { if(DSIZ - z->avail_out) { result = Curl_client_write(data, CLIENTWRITE_BODY, decomp, DSIZ - z->avail_out); /* if !CURLE_OK, clean up, return */ if (result) return exit_zlib(z, &k->zlib_init, result); } /* Done?; clean up, return */ /* We should really check the gzip CRC here */ if (status == Z_STREAM_END) { if (inflateEnd(z) == Z_OK) return exit_zlib(z, &k->zlib_init, result); else return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z)); } /* Done with these bytes, exit */ if (status == Z_OK && z->avail_in == 0 && z->avail_out > 0) return result; } else { /* Error; exit loop, handle below */ return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z)); } } } #endif /* HAVE_LIBZ */