Changelog for 4.6.2 (v4-stable)

Version 4.6.2 [v4-stable] (rgerhards), 2010-03-26

• new feature: “.” action type added to support writing files to relative pathes (this is primarily meant as a debug aid)
• new feature: $OMFileAsyncWriting directive added it permits to specifiy if asynchronous writing should be done or not
• bugfix(temporary): message-induced off-by-one error (potential segfault)
  Some types of malformed messages could trigger an off-by-one error (for example, \0 or \n as the last character, and generally control character escaption is questionable). This is due to not strictly following a the \0 or string counted string paradigm (during the last optimization on the cstring class). As a temporary fix, we have introduced a proper recalculation of the size. However, a final patch is expected in the future. See bug tracker for further details and when the final patch will be available: http://bugzilla.adiscon.com/show_bug.cgi?id=184 Note that the current patch is considered sufficient to solve the situation, but it requires a bit more runtime than desirable.
• bugfix: potential segfault in dynafile cache
  This bug was triggered by an open failure. The the cache was full and a new entry needed to be placed inside it, a victim for eviction was selected. That victim was freed, then the open of the new file tried. If the open failed, the victim entry was still freed, and the function exited. However, on next invocation and cache search, the victim entry was used as if it were populated, most probably resulting in a segfault.
• bugfix: race condition during directory creation
  If multiple files try to create a directory at (almost) the same time, some of them may fail. This is a data race and also exists with other processes that may create the same directory. We do now check for this condition and gracefully handle it.
• bugfix: potential re-use of free()ed file stream object in omfile
  when dynaCache is enabled, the cache is full, a new entry needs to be allocated, thus the LRU discarded, then a new entry is opend and that fails. In that case, it looks like the discarded stream may be reused improperly (based on code analysis, test case and confirmation pending)
• added new property replacer option “date-rfc3164-buggyday” primarily to ease migration from syslog-ng. See property replacer doc for details. [backport from 5.5.3 because urgently needed by some]
• improved testbench
• bugfix: invalid buffer write in (file) stream class
  currently being accessed buffer could be overwritten with new data. While this probably did not cause access violations, it could case loss and/or duplication of some data (definitely a race with no deterministic outcome)
• bugfix: potential hang condition during filestream close predicate was not properly checked when waiting for the background file writer
• bugfix: improper synchronization when “$OMFileFlushOnTXEnd on” was used
  Internal data structures were not properly protected due to missing mutex calls.
• bugfix: potential data loss during file stream shutdown
• bugfix: potential problems during file stream shutdown
  The shutdown/close sequence was not clean, what potentially (but unlikely) could lead to some issues. We have not been able to describe any fatal cases, but there was some bug potential. Sequence has now been straighted out.
• bugfix: potential problem (loop, abort) when file write error occured
  When a write error occured in stream.c, variable iWritten had the error code but this was handled as if it were the actual number of bytes written. That was used in pointer arithmetic later on, and thus could lead to all sorts of problems. However, this could only happen if the error was EINTR or the file in question was a tty. All other cases were handled properly. Now, iWritten is reset to zero in such cases, resulting in proper retries.
• bugfix: $omfileFlushOnTXEnd was turned on when set to off and vice versa due to an invalid check
• bugfix: recent patch to fix small memory leak could cause invalid free.
  This could only happen during config file parsing.
• bugfix(minor): handling of extremely large strings in dbgprintf() fixed
  Previously, it could lead to garbagge output and, in extreme cases, also to segfaults. Note: this was a problem only when debug output was actually enabled, so it caused no problem in production use.
• bugfix(minor): BSD_SO_COMPAT query function had some global vars not properly initialized. However, in practice the loader initializes them with zero, the desired value, so there were no actual issue in almost all cases.