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/* Maps several pages with or without MAP_NORESEVE.
Mappings with MAP_NORESEVE do not show in /proc/self/xmap
(only in /proc/self/rmap) until they actually materialize.
Very nice from Solaris kernel :-(
*/
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <wait.h>
#include <sys/mman.h>
#include <sys/param.h>
static void *do_map(int flags)
{
flags |= MAP_PRIVATE | MAP_ANON;
void *addr = mmap(0, PAGESIZE, PROT_READ | PROT_WRITE, flags, -1, 0);
if (addr == NULL) {
perror("mmap");
exit(1);
} else {
return addr;
}
}
static void *do_dlopen(const char *pathname)
{
int mode = RTLD_LAZY | RTLD_LOCAL;
void *handle = dlopen(pathname, mode);
if (handle == NULL) {
fprintf(stderr, "dlopen failed for %s: %s",
pathname, dlerror());
exit(1);
} else {
return handle;
}
}
int main(int argc, const char *argv[])
{
do_map(MAP_NORESERVE);
do_dlopen("libm.so");
do_map(0);
do_map(0);
do_map(MAP_NORESERVE);
do_dlopen("liby.so");
do_map(MAP_NORESERVE);
do_map(0);
do_map(0);
do_map(MAP_NORESERVE);
do_map(MAP_NORESERVE);
do_dlopen("libz.so");
do_map(MAP_NORESERVE);
do_map(MAP_NORESERVE);
do_map(0);
pid_t pid = fork();
if (pid == -1) {
perror("fork");
exit(1);
}
if (pid == 0) {
do_map(MAP_NORESERVE);
do_map(0);
do_map(0);
do_dlopen("libw.so");
do_map(0);
do_map(MAP_NORESERVE);
do_map(MAP_NORESERVE);
do_map(0);
printf("CHILD: PASSED\n");
fflush(stdout);
return 0;
}
int status;
if (waitpid(pid, &status, 0) != pid) {
perror("waitpid");
} else if ((WIFEXITED(status) != 0) && (WEXITSTATUS(status) == 0)) {
printf("PASSED\n");
} else {
fprintf(stderr, "FAILED: child exited with unexpected status %s %d\n",
WIFEXITED(status) ? "exit" : "signal",
WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status));
}
return 0;
}
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