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#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#define N_SERVERS 3 /* Number of servers in the example cluster */
static int ensureDir(const char *dir)
{
int rv;
struct stat sb;
rv = stat(dir, &sb);
if (rv == -1) {
if (errno == ENOENT) {
rv = mkdir(dir, 0700);
if (rv != 0) {
printf("error: create directory '%s': %s", dir,
strerror(errno));
return 1;
}
} else {
printf("error: stat directory '%s': %s", dir, strerror(errno));
return 1;
}
} else {
if ((sb.st_mode & S_IFMT) != S_IFDIR) {
printf("error: path '%s' is not a directory", dir);
return 1;
}
}
return 0;
}
static void forkServer(const char *topLevelDir, unsigned i, pid_t *pid)
{
*pid = fork();
if (*pid == 0) {
char *dir = malloc(strlen(topLevelDir) + strlen("/D") + 1);
char *id = malloc(N_SERVERS / 10 + 2);
char *argv[] = {"./example/server", dir, id, NULL};
char *envp[] = {NULL};
int rv;
sprintf(dir, "%s/%u", topLevelDir, i + 1);
rv = ensureDir(dir);
if (rv != 0) {
abort();
}
sprintf(id, "%u", i + 1);
execve("./example/server", argv, envp);
}
}
int main(int argc, char *argv[])
{
const char *topLevelDir = "/tmp/raft";
struct timespec now;
pid_t pids[N_SERVERS];
unsigned i;
int rv;
if (argc > 2) {
printf("usage: example-cluster [<dir>]\n");
return 1;
}
if (argc == 2) {
topLevelDir = argv[1];
}
/* Make sure the top level directory exists. */
rv = ensureDir(topLevelDir);
if (rv != 0) {
return rv;
}
/* Spawn the cluster nodes */
for (i = 0; i < N_SERVERS; i++) {
forkServer(topLevelDir, i, &pids[i]);
}
/* Seed the random generator */
timespec_get(&now, TIME_UTC);
srandom((unsigned)(now.tv_nsec ^ now.tv_sec));
while (1) {
struct timespec interval;
int status;
/* Sleep a little bit. */
interval.tv_sec = 1 + random() % 15;
interval.tv_nsec = 0;
rv = nanosleep(&interval, NULL);
if (rv != 0) {
printf("error: sleep: %s", strerror(errno));
}
/* Kill a random server. */
i = (unsigned)(random() % N_SERVERS);
rv = kill(pids[i], SIGINT);
if (rv != 0) {
printf("error: kill server %d: %s", i, strerror(errno));
}
waitpid(pids[i], &status, 0);
rv = nanosleep(&interval, NULL);
if (rv != 0) {
printf("error: sleep: %s", strerror(errno));
}
forkServer(topLevelDir, i, &pids[i]);
}
return 0;
}
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