#define _GNU_SOURCE
#include <errno.h>
#include <stdio.h>
#include <assert.h>
extern char *__progname;
int
main (int argc, char **argv)
{
printf ("PISN = %s\nPIN = %s\n_PN = %s\n",
program_invocation_short_name, program_invocation_name, __progname);
/* assertion reveals the value of __uclibc_progname */
assert (0);
}
The output of the program should be as follows:
$ progname
PISN = progname
PIN = ./progname
_PN = progname
progname: progname.c: 14: main: Assertion `0' failed.
Aborted
Yet the actual result on an unfixed, shared uClibc is:
$ ./progname
PISN = (null)
PIN = (null)
_PN = progname
(null): progname.c: 14: main: Assertion `0' failed.
Aborted
uClibc tries to arrange for __progname to occupy the same memory address as program_invocation_short_name and the hidden variable __uclibc_progname. It also arranges for program_invocation_name to similarly overlap the hidden variable __progname_full.
In __uClibc_main(), only one variable from each group is actually set.
This would be fine if the magic to overlap the variables actually worked. But it does not when uClibc is a shared library.
I've attached a patch which adds extra assignments so that all 5 variables are initialized.
uClibc-0.9.29-progname.diff [^] (698 bytes) 01-04-08 02:57 
