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#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <unistd.h>
#define NUM_PROCESSES 4000
int value(void);
typedef enum
{
NONE = 0,
READY,
LIVEPATCHED,
} state_t;
int
child_main(volatile state_t *state)
{
*state = READY;
while (value()) {
sleep(1);
}
*state = LIVEPATCHED;
return 0;
}
int
main(void)
{
pid_t pids[NUM_PROCESSES];
volatile state_t *states;
states = mmap(NULL, NUM_PROCESSES * sizeof(state_t), PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
for (int i = 0; i < NUM_PROCESSES; i++) {
states[i] = NONE;
pids[i] = fork();
if (pids[i] == 0) {
/* Child. */
return child_main(&states[i]);
}
}
for (int i = 0; i < NUM_PROCESSES; i++) {
while (states[i] != READY)
usleep(1000);
}
puts("Processes launched");
for (int i = 0; i < NUM_PROCESSES; i++) {
while (states[i] != LIVEPATCHED)
usleep(1000);
}
for (int i = 0; i < NUM_PROCESSES; i++) {
int wstatus;
waitpid(pids[i], &wstatus, 0);
if (WIFEXITED(wstatus)) {
int r = WEXITSTATUS(wstatus);
if (r) {
printf("Process %d returned non-zero: %d\n", pids[i], r);
}
}
else {
printf("Process %d ended without calling exit\n", pids[i]);
}
}
munmap((void *)states, NUM_PROCESSES * sizeof(state_t));
puts("Processes finished");
return 0;
}
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