glibc/elf/tst-execstack.c

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* sysdeps/i386/dl-machine.h (RTLD_START): Set __libc_stack_end before calling _dl_start, using GOTOFF access. * configure.in (libc_cv_z_execstack): New check. * configure: Regenerated. * config.make.in (have-z-execstack): New variable set by it. * elf/tst-execstack.c: New file. * elf/tst-execstack-mod.c: New file. * elf/tst-execstack-needed.c: New file. * elf/Makefile (tests-execstack-yes, modules-execstack-yes): New variables. (tests, modules-names): Conditionally include them. (distribute): Add tst-execstack-mod.c here. ($(objpfx)tst-execstack, $(objpfx)tst-execstack.out): New targets. (LDFLAGS-tst-execstack, LDFLAGS-tst-execstack-mod): New variables. ($(objpfx)tst-execstack-needed): New target. (LDFLAGS-tst-execstack-needed): New variable. * sysdeps/generic/ldsodefs.h (struct rtld_global): Add _dl_stack_flags and _dl_make_stack_executable_hook. Declare _dl_make_stack_executable. * elf/rtld.c (_rtld_global): Add initializer for _dl_stack_flags. (dl_main): Reset _dl_stack_flags according to PT_GNU_STACK phdr. Initialize _dl_make_stack_executable_hook. * elf/dl-support.c: Define those new variables. (_dl_non_dynamic_init): Scan phdrs for PT_GNU_STACK. (_dl_phdr): Fix type. * elf/dl-load.c (_dl_map_object_from_fd): Grok PT_GNU_STACK phdr and enable execute permission for the stack if necessary. * sysdeps/generic/dl-execstack.c: New file. * elf/Makefile (dl-routines): Add it. * elf/Versions (ld: GLIBC_PRIVATE): Add _dl_make_stack_executable. * sysdeps/unix/sysv/linux/dl-execstack.c: New file.
2003-09-23 12:07:26 +00:00
/* Test program for making nonexecutable stacks executable
on load of a DSO that requires executable stacks. */
#include <dlfcn.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <error.h>
static void
print_maps (void)
{
#if 0
char *cmd = NULL;
asprintf (&cmd, "cat /proc/%d/maps", getpid ());
system (cmd);
free (cmd);
#endif
}
static void deeper (void (*f) (void));
#if USE_PTHREADS
# include <pthread.h>
static void *
tryme_thread (void *f)
{
(*((void (*) (void)) f)) ();
return 0;
}
static pthread_barrier_t startup_barrier, go_barrier;
static void *
waiter_thread (void *arg)
{
void **f = arg;
pthread_barrier_wait (&startup_barrier);
pthread_barrier_wait (&go_barrier);
(*((void (*) (void)) *f)) ();
return 0;
}
#endif
static int
do_test (void)
{
void *f;
#if USE_PTHREADS
/* Create some threads while stacks are nonexecutable. */
#define N 5
pthread_t thr[N];
pthread_barrier_init (&startup_barrier, NULL, N + 1);
pthread_barrier_init (&go_barrier, NULL, N + 1);
for (int i = 0; i < N; ++i)
{
int rc = pthread_create (&thr[i], NULL, &waiter_thread, &f);
if (rc)
error (1, rc, "pthread_create");
}
/* Make sure they are all there using their stacks. */
pthread_barrier_wait (&startup_barrier);
puts ("threads waiting");
#endif
print_maps ();
/* Loading this module should force stacks to become executable. */
void *h = dlopen ("tst-execstack-mod.so", RTLD_LAZY);
if (h == NULL)
{
printf ("cannot load: %s\n", dlerror ());
return 1;
}
f = dlsym (h, "tryme");
if (f == NULL)
{
printf ("symbol not found: %s\n", dlerror ());
return 1;
}
/* Test if that really made our stack executable.
The `tryme' function should crash if not. */
(*((void (*) (void)) f)) ();
print_maps ();
/* Test that growing the stack region gets new executable pages too. */
deeper ((void (*) (void)) f);
print_maps ();
#if USE_PTHREADS
/* Test that a fresh thread now gets an executable stack. */
{
pthread_t th;
int rc = pthread_create (&th, NULL, &tryme_thread, f);
if (rc)
error (1, rc, "pthread_create");
}
puts ("threads go");
/* The existing threads' stacks should have been changed.
Let them run to test it. */
pthread_barrier_wait (&go_barrier);
pthread_exit (0);
#endif
return 0;
}
static void
deeper (void (*f) (void))
{
char stack[1100 * 1024];
memfrob (stack, sizeof stack);
(*f) ();
memfrob (stack, sizeof stack);
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"