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#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
static void *setuid_124(void *unused)
{
int status;
status = setuid(124);
if (status < 0) {
perror("setuid");
pthread_exit((void *)-1);
}
if (getuid() != 124) {
perror("getuid");
pthread_exit((void *)-1);
}
pthread_exit(NULL);
}
static void pterror(const char *message, int error)
{
fprintf(stderr, "%s: %s\n", message, strerror(error));
}
int main(void)
{
pthread_t thread;
int child_status;
void *result;
int status;
switch(fork()) {
case -1:
perror("fork");
exit(EXIT_FAILURE);
case 0: /* child */
status = setuid(123);
if (status < 0) {
perror("setuid");
exit(EXIT_FAILURE);
}
if (getuid() != 123) {
perror("getuid");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
default: /* parent */
break;
}
status = wait(&child_status);
if (status < 0 || child_status != 0) {
perror("wait()");
exit(EXIT_FAILURE);
}
if (getuid() != 0) {
fprintf(stderr, "getuid() == %d != 0\n", getuid());
exit(EXIT_FAILURE);
}
status = pthread_create(&thread, NULL, setuid_124, NULL);
if (status != 0) {
pterror("pthread_create", status);
exit(EXIT_FAILURE);
}
status = pthread_join(thread, &result);
if (status != 0) {
pterror("pthread_create", status);
exit(EXIT_FAILURE);
}
if (result != NULL) {
fprintf(stderr, "result != NULL\n");
exit(EXIT_FAILURE);
}
if (getuid() != 124) {
fprintf(stderr, "getuid() == %d != 124\n", getuid());
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
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