/** * @file llmime.cpp * @author Phoenix * @date 2006-12-20 * @brief Implementation of mime tools. * * $LicenseInfo:firstyear=2006&license=viewerlgpl$ * Second Life Viewer Source Code * Copyright (C) 2010, Linden Research, Inc. * * 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 of the License only. * * 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 * * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA * $/LicenseInfo$ */ #include "linden_common.h" #include "llmime.h" #include <vector> #include "llmemorystream.h" /** * Useful constants. */ // Headers specified in rfc-2045 will be canonicalized below. static const std::string CONTENT_LENGTH("Content-Length"); static const std::string CONTENT_TYPE("Content-Type"); static const S32 KNOWN_HEADER_COUNT = 6; static const std::string KNOWN_HEADER[KNOWN_HEADER_COUNT] = { CONTENT_LENGTH, CONTENT_TYPE, std::string("MIME-Version"), std::string("Content-Transfer-Encoding"), std::string("Content-ID"), std::string("Content-Description"), }; // parser helpers static const std::string MULTIPART("multipart"); static const std::string BOUNDARY("boundary"); static const std::string END_OF_CONTENT_PARAMETER("\r\n ;\t"); static const std::string SEPARATOR_PREFIX("--"); //static const std::string SEPARATOR_SUFFIX("\r\n"); /* Content-Type: multipart/mixed; boundary="segment" Content-Length: 24832 --segment Content-Type: image/j2c Content-Length: 23715 <data> --segment Content-Type: text/xml; charset=UTF-8 <meta data> EOF */ /** * LLMimeIndex */ /** * @class LLMimeIndex::Impl * @brief Implementation details of the mime index class. * @see LLMimeIndex */ class LLMimeIndex::Impl { public: Impl() : mOffset(-1), mUseCount(1) {} Impl(LLSD headers, S32 offset) : mHeaders(headers), mOffset(offset), mUseCount(1) {} public: LLSD mHeaders; S32 mOffset; S32 mUseCount; typedef std::vector<LLMimeIndex> sub_part_t; sub_part_t mAttachments; }; LLSD LLMimeIndex::headers() const { return mImpl->mHeaders; } S32 LLMimeIndex::offset() const { return mImpl->mOffset; } S32 LLMimeIndex::contentLength() const { // Find the content length in the headers. S32 length = -1; LLSD content_length = mImpl->mHeaders[CONTENT_LENGTH]; if(content_length.isDefined()) { length = content_length.asInteger(); } return length; } std::string LLMimeIndex::contentType() const { std::string type; LLSD content_type = mImpl->mHeaders[CONTENT_TYPE]; if(content_type.isDefined()) { type = content_type.asString(); } return type; } bool LLMimeIndex::isMultipart() const { bool multipart = false; LLSD content_type = mImpl->mHeaders[CONTENT_TYPE]; if(content_type.isDefined()) { std::string type = content_type.asString(); int comp = type.compare(0, MULTIPART.size(), MULTIPART); if(0 == comp) { multipart = true; } } return multipart; } S32 LLMimeIndex::subPartCount() const { return mImpl->mAttachments.size(); } LLMimeIndex LLMimeIndex::subPart(S32 index) const { LLMimeIndex part; if((index >= 0) && (index < (S32)mImpl->mAttachments.size())) { part = mImpl->mAttachments[index]; } return part; } LLMimeIndex::LLMimeIndex() : mImpl(new LLMimeIndex::Impl) { } LLMimeIndex::LLMimeIndex(LLSD headers, S32 content_offset) : mImpl(new LLMimeIndex::Impl(headers, content_offset)) { } LLMimeIndex::LLMimeIndex(const LLMimeIndex& mime) : mImpl(mime.mImpl) { ++mImpl->mUseCount; } LLMimeIndex::~LLMimeIndex() { if(0 == --mImpl->mUseCount) { delete mImpl; } } LLMimeIndex& LLMimeIndex::operator=(const LLMimeIndex& mime) { // Increment use count first so that we handle self assignment // automatically. ++mime.mImpl->mUseCount; if(0 == --mImpl->mUseCount) { delete mImpl; } mImpl = mime.mImpl; return *this; } bool LLMimeIndex::attachSubPart(LLMimeIndex sub_part) { // *FIX: Should we check for multi-part? if(mImpl->mAttachments.size() < S32_MAX) { mImpl->mAttachments.push_back(sub_part); return true; } return false; } /** * LLMimeParser */ /** * @class LLMimeParser::Impl * @brief Implementation details of the mime parser class. * @see LLMimeParser */ class LLMimeParser::Impl { public: // @brief Constructor. Impl(); // @brief Reset this for a new parse. void reset(); /** * @brief Parse a mime entity to find the index information. * * This method will scan the istr until a single complete mime * entity is read, an EOF, or limit bytes have been scanned. The * istr will be modified by this parsing, so pass in a temporary * stream or rewind/reset the stream after this call. * @param istr An istream which contains a mime entity. * @param limit The maximum number of bytes to scan. * @param separator The multipart separator if it is known. * @param is_subpart Set true if parsing a multipart sub part. * @param index[out] The parsed output. * @return Returns true if an index was parsed and no errors occurred. */ bool parseIndex( std::istream& istr, S32 limit, const std::string& separator, bool is_subpart, LLMimeIndex& index); protected: /** * @brief parse the headers. * * At the end of a successful parse, mScanCount will be at the * start of the content. * @param istr The input stream. * @param limit maximum number of bytes to process * @param headers[out] A map of the headers found. * @return Returns true if the parse was successful. */ bool parseHeaders(std::istream& istr, S32 limit, LLSD& headers); /** * @brief Figure out the separator string from a content type header. * * @param multipart_content_type The content type value from the headers. * @return Returns the separator string. */ std::string findSeparator(std::string multipart_content_type); /** * @brief Scan through istr past the separator. * * @param istr The input stream. * @param limit Maximum number of bytes to scan. * @param separator The multipart separator. */ void scanPastSeparator( std::istream& istr, S32 limit, const std::string& separator); /** * @brief Scan through istr past the content of the current mime part. * * @param istr The input stream. * @param limit Maximum number of bytes to scan. * @param headers The headers for this mime part. * @param separator The multipart separator if known. */ void scanPastContent( std::istream& istr, S32 limit, LLSD headers, const std::string separator); /** * @brief Eat CRLF. * * This method has no concept of the limit, so ensure you have at * least 2 characters left to eat before hitting the limit. This * method will increment mScanCount as it goes. * @param istr The input stream. * @return Returns true if CRLF was found and consumed off of istr. */ bool eatCRLF(std::istream& istr); // @brief Returns true if parsing should continue. bool continueParse() const { return (!mError && mContinue); } // @brief anonymous enumeration for parse buffer size. enum { LINE_BUFFER_LENGTH = 1024 }; protected: S32 mScanCount; bool mContinue; bool mError; char mBuffer[LINE_BUFFER_LENGTH]; }; LLMimeParser::Impl::Impl() { reset(); } void LLMimeParser::Impl::reset() { mScanCount = 0; mContinue = true; mError = false; mBuffer[0] = '\0'; } bool LLMimeParser::Impl::parseIndex( std::istream& istr, S32 limit, const std::string& separator, bool is_subpart, LLMimeIndex& index) { LLSD headers; bool parsed_something = false; if(parseHeaders(istr, limit, headers)) { parsed_something = true; LLMimeIndex mime(headers, mScanCount); index = mime; if(index.isMultipart()) { // Figure out the separator, scan past it, and recurse. std::string ct = headers[CONTENT_TYPE].asString(); std::string sep = findSeparator(ct); scanPastSeparator(istr, limit, sep); while(continueParse() && parseIndex(istr, limit, sep, true, mime)) { index.attachSubPart(mime); } } else { // Scan to the end of content. scanPastContent(istr, limit, headers, separator); if(is_subpart) { scanPastSeparator(istr, limit, separator); } } } if(mError) return false; return parsed_something; } bool LLMimeParser::Impl::parseHeaders( std::istream& istr, S32 limit, LLSD& headers) { while(continueParse()) { // Get the next line. // We subtract 1 from the limit so that we make sure // not to read past limit when we get() the newline. S32 max_get = llmin((S32)LINE_BUFFER_LENGTH, limit - mScanCount - 1); istr.getline(mBuffer, max_get, '\r'); mScanCount += istr.gcount(); int c = istr.get(); if(EOF == c) { mContinue = false; return false; } ++mScanCount; if(c != '\n') { mError = true; return false; } if(mScanCount >= limit) { mContinue = false; } // Check if that's the end of headers. if('\0' == mBuffer[0]) { break; } // Split out the name and value. // *NOTE: The use of strchr() here is safe since mBuffer is // guaranteed to be NULL terminated from the call to getline() // above. char* colon = strchr(mBuffer, ':'); if(!colon) { mError = true; return false; } // Cononicalize the name part, and store the name: value in // the headers structure. We do this by iterating through // 'known' headers and replacing the value found with the // correct one. // *NOTE: Not so efficient, but iterating through a small // subset should not be too much of an issue. std::string name(mBuffer, colon++ - mBuffer); while(isspace(*colon)) ++colon; std::string value(colon); for(S32 ii = 0; ii < KNOWN_HEADER_COUNT; ++ii) { if(0 == LLStringUtil::compareInsensitive(name, KNOWN_HEADER[ii])) { name = KNOWN_HEADER[ii]; break; } } headers[name] = value; } if(headers.isUndefined()) return false; return true; } std::string LLMimeParser::Impl::findSeparator(std::string header) { // 01234567890 //Content-Type: multipart/mixed; boundary="segment" std::string separator; std::string::size_type pos = header.find(BOUNDARY); if(std::string::npos == pos) return separator; pos += BOUNDARY.size() + 1; std::string::size_type end; if(header[pos] == '"') { // the boundary is quoted, find the end from pos, and take the // substring. end = header.find('"', ++pos); if(std::string::npos == end) { // poorly formed boundary. mError = true; } } else { // otherwise, it's every character until a whitespace, end of // line, or another parameter begins. end = header.find_first_of(END_OF_CONTENT_PARAMETER, pos); if(std::string::npos == end) { // it goes to the end of the string. end = header.size(); } } if(!mError) separator = header.substr(pos, end - pos); return separator; } void LLMimeParser::Impl::scanPastSeparator( std::istream& istr, S32 limit, const std::string& sep) { std::ostringstream ostr; ostr << SEPARATOR_PREFIX << sep; std::string separator = ostr.str(); bool found_separator = false; while(!found_separator && continueParse()) { // Subtract 1 from the limit so that we make sure not to read // past limit when we get() the newline. S32 max_get = llmin((S32)LINE_BUFFER_LENGTH, limit - mScanCount - 1); istr.getline(mBuffer, max_get, '\r'); mScanCount += istr.gcount(); if(istr.gcount() >= LINE_BUFFER_LENGTH - 1) { // that's way too long to be a separator, so ignore it. continue; } int c = istr.get(); if(EOF == c) { mContinue = false; return; } ++mScanCount; if(c != '\n') { mError = true; return; } if(mScanCount >= limit) { mContinue = false; } if(0 == LLStringUtil::compareStrings(std::string(mBuffer), separator)) { found_separator = true; } } } void LLMimeParser::Impl::scanPastContent( std::istream& istr, S32 limit, LLSD headers, const std::string separator) { if(headers.has(CONTENT_LENGTH)) { S32 content_length = headers[CONTENT_LENGTH].asInteger(); // Subtract 2 here for the \r\n after the content. S32 max_skip = llmin(content_length, limit - mScanCount - 2); istr.ignore(max_skip); mScanCount += max_skip; // *NOTE: Check for hitting the limit and eof here before // checking for the trailing EOF, because our mime parser has // to gracefully handle incomplete mime entites. if((mScanCount >= limit) || istr.eof()) { mContinue = false; } else if(!eatCRLF(istr)) { mError = true; return; } } } bool LLMimeParser::Impl::eatCRLF(std::istream& istr) { int c = istr.get(); ++mScanCount; if(c != '\r') { return false; } c = istr.get(); ++mScanCount; if(c != '\n') { return false; } return true; } LLMimeParser::LLMimeParser() : mImpl(* new LLMimeParser::Impl) { } LLMimeParser::~LLMimeParser() { delete & mImpl; } void LLMimeParser::reset() { mImpl.reset(); } bool LLMimeParser::parseIndex(std::istream& istr, LLMimeIndex& index) { std::string separator; return mImpl.parseIndex(istr, S32_MAX, separator, false, index); } bool LLMimeParser::parseIndex( const std::vector<U8>& buffer, LLMimeIndex& index) { LLMemoryStream mstr(&buffer[0], buffer.size()); return parseIndex(mstr, buffer.size() + 1, index); } bool LLMimeParser::parseIndex( std::istream& istr, S32 limit, LLMimeIndex& index) { std::string separator; return mImpl.parseIndex(istr, limit, separator, false, index); } bool LLMimeParser::parseIndex(const U8* buffer, S32 length, LLMimeIndex& index) { LLMemoryStream mstr(buffer, length); return parseIndex(mstr, length + 1, index); } /* bool LLMimeParser::verify(std::istream& isr, LLMimeIndex& index) const { return false; } bool LLMimeParser::verify(U8* buffer, S32 length, LLMimeIndex& index) const { LLMemoryStream mstr(buffer, length); return verify(mstr, index); } */