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From: georg.wild@gmx.de To: gcc-gnats@gcc.gnu.org Subject: c/4391: memcpy(buf, base, len); defunction compiling bind with -O2 Date: Tue, 25 Sep 2001 03:36:00 -0000 [thread overview] Message-ID: <20010925102614.28515.qmail@sourceware.cygnus.com> (raw) >Number: 4391 >Category: c >Synopsis: memcpy(buf, base, len); defunction compiling bind with -O2 >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: sw-bug >Submitter-Id: net >Arrival-Date: Tue Sep 25 03:36:01 PDT 2001 >Closed-Date: >Last-Modified: >Originator: georg.wild@gmx.de >Release: latest cvs snapshot >Organization: >Environment: i686-pc-linux-gnu linux 2.2.19 glibc 2.2.4 and mostly newest libraries >Description: Sorry, but it was not possible for me producing a compilable example because this bug is somehow connected with libraries and .....! Therefore I'll describe what happens! It occurs compiling ftp://ftp.isc.org/isc/bind9/9.2.0rc4/bind-9.2.0rc4.tar.gz and specially libisc. The position where it is first seen in the main program is in: isc_result_t isc_file_progname(const char *filename, char *buf, size_t buflen) { const char *base; size_t len; REQUIRE(filename != NULL); REQUIRE(buf != NULL); base = isc_file_basename(filename); len = strlen(base) + 1; if (len > buflen) return (ISC_R_NOSPACE); memcpy(buf, base, len); return (ISC_R_SUCCESS); } When reaching the memcpy line, I see in ddd the program returning to the main program without setting ISC_R_SUCCESS. In the asm tab there is a jmp-Funktion. Pressing next in machine code returns directly to the main program! But I think the real problem is in file.c, because it works when file.c is compiled -O0. -O2 doesn't work. Because I don't see any other related function, I think the miscompiled funktion is const char * isc_file_basename(const char *filename) { char *s; REQUIRE(filename != NULL); s = strrchr(filename, '/'); if (s == NULL) return (filename); return (s + 1); } Debugging this piece of code results: Starting with filename="/root/bind-9.2.0rc4/bin/named/named" s=strrchr(..) results s="/named". Executing this if statement changes the value of s; it got "/root/bind-..../named". After executing the return function the value of s is "named"; executing the whole procedure returns the right value: "named". But I think there seems to be a somehow wrong memory allocation. >How-To-Repeat: Compiliung this bind release in the usual manor. >Fix: Compile file.c using -O0. >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2001-09-25 3:36 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2001-09-25 3:36 georg.wild [this message] 2001-09-25 4:16 Graham Stott 2002-04-24 15:22 rth
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