Tor Lillqvist writes:
> (The current gnuwin32 build of RegEx-Spencer, "3.8.g.3", uses the DLL
> name rxspencer.dll. Good.)
And whoopee, it turns out that there is a dangerous flaw in the
3.8.g.3 version of the RegEx-Spencer library as distributed by
gnuwin32.
The obsoleted 3.8 version (which is very hard to find from the
gnuwin32 site, I found it last week, but can't find it now...) works
correctly, but as I said in my previous message, confusingly uses the
same name for the DLL as gnuwin32's build of RegEx-GNU does.
Try this simple test program against both versions of the
RegEx-Spencer library. Build it in a clean mingw environment or in
MSVC.
#include <stdio.h>
#include <sys/types.h>
#include <regex.h>
int
main (int argc, char **argv)
{
const char *pattern = "[ \t]*<mailto:([^@>]+)@?([^ \n\t\r>]*)";
const char *string = " <mailto:[EMAIL PROTECTED]>";
regex_t re;
int j, rc;
regmatch_t match[3];
rc = regcomp (&re, pattern, REG_EXTENDED|REG_ICASE);
for (j=0;j<3;j++)
{
match[j].rm_so = -1;
match[j].rm_eo = -1;
}
rc = regexec (&re, string, 3, match, 0);
printf ("Should have matched, rc=%d, match={(%ld,%ld),(%ld,%ld),(%ld,%ld)}\n",
rc,
match[0].rm_so, match[0].rm_eo,
match[1].rm_so, match[1].rm_eo,
match[2].rm_so, match[2].rm_eo);
return 0;
}
When run against the 3.8.g.3 DLL, you will see that the match array is
filled in incorrectly after the match:
Should have matched, rc=0, match={(0,0),(46,0),(9,0)}
If you build it with MSVC, it will even crash after printing that...
When run against the RegEx-Spencer 3.8 DLL (called regex.dll, but not
the same as the regex.dll in RegEx-GNU), the result is correct:
Should have matched, rc=0, match={(0,46),(9,24),(25,46)}
It turns out that the 3.8.g.3 version of the RegEx-Spencer library
seems to have been built in an environment where off_t is long long,
not long like it is in the Mircosoft C library and mingw. What the
heck?
This is horrible. It means that the RegEx-Spencer library thinks the
regmatch_t struct is 16 bytes (two long longs), while normal
mingw-compiled code thinks it is 8 bytes (two longs). It means that
when calling regexec(), it will overwrite the match array, scribbling
over whatever happens to be allocated after it in memory. (This
presumably explains the crash when the above program has been built
with MSVC, it happens to scribble over main's return address on the
stack, or something like that.)
To see this horror in action, add some variables before and after the
"match" array in the sample code above, and print out their values
before and after the regexec() call.
Please, fix this as soon as possible.
Either 1) Recompile RegEx-Spencer in a proper mingw environment
without any mysterious add-on secret sauce that redefines off_t. (In
this case, remember that you *must* also use a different name for the
fixed DLL, as it is no longer ABI compatible with the old
rxspencer.dll. This will also make it stand out that executables that
link to the new rxspencer-1.dll (or whatever you choose to call it)
aren't expected to work with the old one.)
Or, 2) modify the regex.h to spell out that regoff_t is explicitly
typedeffed as long long. In this case no new DLL name or "bin" package
is necessary, but a new version of the "lib" package with the modified
regex.h is of course needed.
--tml
P.S. I guess the "secret sauce" that redefines off_t as long long is
the "libgw32c" library? But surely using that should not be a
requirement for users of packages like RegEx-Spencer? If the intention
really is that it is a requirement, then some mechanism should be
introduced that causes an error if one tries to include <regex.h> in a
non-libgw32c-modified environment.
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