diff options
| -rw-r--r-- | apt-pkg/contrib/strutl.cc | 44 |
1 files changed, 40 insertions, 4 deletions
diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc index a04c266ba..eacc7077a 100644 --- a/apt-pkg/contrib/strutl.cc +++ b/apt-pkg/contrib/strutl.cc @@ -658,11 +658,24 @@ string TimeRFC1123(time_t Date) // --------------------------------------------------------------------- /* This pulls full messages from the input FD into the message buffer. It assumes that messages will not pause during transit so no - fancy buffering is used. */ + fancy buffering is used. + + In particular: this reads blocks from the input until it believes + that it's run out of input text. Each block is terminated by a + double newline ('\n' followed by '\n'). As noted below, there is a + bug in this code: it assumes that all the blocks have been read if + it doesn't see additional text in the buffer after the last one is + parsed, which will cause it to lose blocks if the last block + coincides with the end of the buffer. + */ bool ReadMessages(int Fd, vector<string> &List) { char Buffer[64000]; char *End = Buffer; + // Represents any left-over from the previous iteration of the + // parse loop. (i.e., if a message is split across the end + // of the buffer, it goes here) + string PartialMessage; while (1) { @@ -690,6 +703,7 @@ bool ReadMessages(int Fd, vector<string> &List) // Pull the message out string Message(Buffer,I-Buffer); + PartialMessage += Message; // Fix up the buffer for (; I < End && *I == '\n'; I++); @@ -697,10 +711,32 @@ bool ReadMessages(int Fd, vector<string> &List) memmove(Buffer,I,End-Buffer); I = Buffer; - List.push_back(Message); + List.push_back(PartialMessage); + PartialMessage.clear(); } - if (End == Buffer) - return true; + if (End != Buffer) + { + // If there's text left in the buffer, store it + // in PartialMessage and throw the rest of the buffer + // away. This allows us to handle messages that + // are longer than the static buffer size. + PartialMessage += string(Buffer, End); + End = Buffer; + } + else + { + // BUG ALERT: if a message block happens to end at a + // multiple of 64000 characters, this will cause it to + // terminate early, leading to a badly formed block and + // probably crashing the method. However, this is the only + // way we have to find the end of the message block. I have + // an idea of how to fix this, but it will require changes + // to the protocol (essentially to mark the beginning and + // end of the block). + // + // -- dburrows 2008-04-02 + return true; + } if (WaitFd(Fd) == false) return false; |