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Bug fix to HTHost.c

From: Peter Kocks <peter.kocks@baygate.com>
Date: Fri, 19 May 2000 15:12:20 -0700
To: <www-lib@w3.org>
Message-ID: <NDBBJBILNGKNBCDAKIJMEEHACDAA.peter.kocks@baygate.com>
Hi all,

I'm new to this list and have both a
bug to report and a solution.

I can reproducibly crash a custom webbot program
that uses libwww.  The program crashes under a
couple of circumstances (gdb stack traces are
attached at the bottom of this message), but
both are related to two lines of code in HTHost.c

In HTHost.c, starting at line 1099 (current cvs)
HTChannel_delete(host->channel, status);
host->channel = NULL;

The second line (host->channel = NULL) is both
unnecessary and causes libwww crash under certain
conditions.  For  example, any subsequent code that
calls HTChannel_socket(host->channel)) will return
a socket number of "-1".  This will cause a
segfault if something is keyed on socket
number.  E.g. HTEventList_unregister().

I'm not sure what the procedure is, but I'd
like the line host->channel = NULL deleted from
the code base because it is causing some
of my programs to crash.

Thanks in advance

Peter Kocks

Stack traces follow.


Program received signal SIGSEGV, Segmentation fault.
0xdff47971 in HTEventList_unregister (s=-1, type=HTEvent_READ)
    at HTEvtLst.c:457
457         while (cur && (pres = (SockEvents *) HTList_nextObject(cur))) {
(gdb) where
#0  0xdff47971 in HTEventList_unregister (s=-1, type=HTEvent_READ)
    at HTEvtLst.c:457
#1  0xdfeaca8c in HTEvent_unregister (s=-1, type=HTEvent_READ) at
#2  0xdfeaf391 in HTHost_recoverPipe (host=0x8074958) at HTHost.c:841
#3  0xdfeb38fb in HTNet_delete (net=0x80834b0, status=200) at HTNet.c:912
#4  0xdff162ee in HTTPCleanup (req=0x8083310, status=200) at HTTP.c:168
#5  0xdff183ea in HTTPEvent (soc=9, pVoid=0x80827a0, type=HTEvent_READ)
    at HTTP.c:1290
#6  0xdfeae58e in HostEvent (soc=9, pVoid=0xffffffff, type=HTEvent_READ)
    at HTHost.c:196
#7  0xdff475e1 in EventOrder_executeAndDelete () at HTEvtLst.c:321
#8  0xdff48045 in HTEventList_loop (theRequest=0x8072b50) at HTEvtLst.c:762
#9  0x805222c in main (argc=17, argv=0x8047b5c) at RobotMain.c:593


#0  redirection_handler (request=0x8072c30, response=0x8077060, param=0x0,
    status=302) at HTRobot.c:992
#1  0xdfab2b3a in HTNetCall_executeAfter (list=0x8073210, request=0x8072c30,
    status=302) at HTNet.c:314
#2  0xdfab2db5 in HTNet_executeAfterAll (request=0x8072c30, status=302)
    at HTNet.c:420
#3  0xdfab3a8b in HTNet_delete (net=0x8073f48, status=302) at HTNet.c:920
#4  0xdfb16332 in HTTPCleanup (req=0x8072c30, status=302) at HTTP.c:168
#5  0xdfb18452 in HTTPEvent (soc=-1, pVoid=0x8070db0, type=HTEvent_READ)
    at HTTP.c:1294
#6  0xdfb17b7d in HTLoadHTTP (soc=-1, request=0x8072c30) at HTTP.c:967
#7  0xdfab384c in HTNet_newClient (request=0x8072c30) at HTNet.c:808
#8  0xdfab7450 in HTLoad (me=0x8072c30, recursive=-8 '') at HTReqMan.c:1685
#9  0xdfb443e5 in launch_request (request=0x8072c30, recursive=0 '\000')
    at HTAccess.c:77
#10 0xdfb44742 in HTLoadAnchorToChunk (anchor=0x8072ba0, request=0x8072c30)
    at HTAccess.c:243
#11 0x8050d73 in get_robots_txt (
    uri=0x8072970 "http://www.seattletimes.com/robots.txt") at
#12 0x8052063 in main (argc=17, argv=0x8047bc0) at RobotMain.c:527
Received on Friday, 19 May 2000 18:12:51 UTC

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