Date: Fri, 21 Jul 2000 11:15:16 +0100 (BST) From: Martin Hopkins <martin.hopkins@insignia.com> To: Raymond Wiker <Raymond.Wiker@fast.no> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: dlopen() and friends from a statically-linked binary? Message-ID: <14712.8884.57869.666781@whittard.home> In-Reply-To: <14711.10742.914512.819982@raw.gren.fast.no> References: <14711.10742.914512.819982@raw.gren.fast.no>
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>>>>> "Raymond" == Raymond Wiker <Raymond.Wiker@fast.no> writes:
Raymond> raw : ~ $ cat dltest.c
Raymond> #include <dlfcn.h>
Raymond> #include <stdio.h>
Raymond> main()
Raymond> {
Raymond> void *handle;
Raymond> void *sym;
Raymond> handle = dlopen(0, RTLD_LAZY);
Raymond> if (handle == 0)
Raymond> {
Raymond> fprintf(stderr, "dlopen returned 0: %s\n", dlerror());
Raymond> }
Raymond> else
Raymond> {
Raymond> fprintf(stderr, "Handle: %p, main: %p\n", handle, dlsym(handle, "main"));
Raymond> }
Raymond> fprintf(stderr, "Handle: %p, main: %p\n", 0, dlsym(0, "main"));
Raymond> return 0;
Raymond> }
Raymond> raw : ~ $ gcc -static dltest.c -o dltest
Raymond> raw : ~ $ ./dltest
Raymond> dlopen returned 0: Service unavailable
Raymond> Handle: 0x0, main: 0x0
Raymond> raw : ~ $ gcc dltest.c -o dltest
Raymond> raw : ~ $ ./dltest
Raymond> Handle: 0x2805e000, main: 0x0
Raymond> Handle: 0x0, main: 0x0
Raymond> [ Note: this seems wrong; according to the manpage for dlsym, the
Raymond> second call should give the same output as the first. ]
It does, it returns NULL. I'm not sure what your issues with SBCL are
(I'll try to take a look later if I get time). I believe to get your
sample code above to work you want...
gcc dltest.c -Xlinker -export-dynamic -o dltest
This then gives me
Handle: 0x2805d000, main: 0x8048508
Handle: 0x0, main: 0x8048508
Hope this helps,
Martin
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