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Re: [patch] Variable page size support for MIPS/Linux
On Mon, 5 Jan 2004, Maciej W. Rozycki wrote:
> Now, getting back to the subject, please note that I am specifically
> referring to the case when ld.so gets loaded as a result of dlopen() --
> here's a small snippet that depicts what I mean:
>
> #include <dlfcn.h>
> #include <stdio.h>
> #include <unistd.h>
>
> int main(void)
> {
> void *h;
> int (*g)(void);
> int p0, p1;
>
> h = dlopen("/lib/libc.so.6", RTLD_GLOBAL | RTLD_LAZY);
>
> g = dlsym(h, "getpagesize");
>
> p0 = g();
>
> dlclose(h);
>
> p1 = getpagesize();
>
> printf("pagesize: %u, %u\n", p0, p1);
>
> return 0;
> }
>
> With glibc as distributed it outputs bad values of the page size. With
> glibc patched to add sysdeps/unix/sysv/linux/mips/getpagesize.c only, it
> crashes due to the assertion quoted above. While calling dlopen() on
> libc.so isn't that useful itself, it corresponds to a real-life situation
> when both libc.so and ld.so get loaded as a part of references to NSS
> modules from static executables.
FYI, the above program prints:
pagesize: 65536, 4096
on my system with unpatched glibc and:
pagesize: 4096, 4096
after my fix. My system is currently configured for a 4kB page size --
for page sizes of 16kB and 64kB substitute 16384 and 65536 respectively
for 4096 above.
--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +