/*
 * Create dead-lock and print debugging data.
 */
#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <grp.h>

#define ARRAY_SIZE(a) ((sizeof (a)) / sizeof (*(a)))
#define BUFLEN 4096
#define GROUPS 100

static pthread_t thread[100];

static const char user[] = "Administrator";

static void *run(void *data) {
	unsigned int round;

	unsigned int self = (unsigned int)(unsigned long)data;
	pthread_t tid = pthread_self();

	printf("[%d] POSIX thread ID is %u\n", self, (unsigned int)tid);

	for (round = 0; round < 100; round++) {
#if 0
		setgrent();
		while (1) {
			int i;
			char buf[BUFLEN];
			struct group grp, *grpp;

			i = getgrent_r(&grp, buf, BUFLEN, &grpp);
			if (i)
				break;
			printf("%s (%d):", grpp->gr_name, grpp->gr_gid);
			for (i = 0; ; i++) {
				if (grpp->gr_mem[i] == NULL)
					break;
				printf(".");
				// printf(" %s", grpp->gr_mem[i]);
			}
			printf("\n");
		}
		endgrent();
#else
		int r, ngroups = GROUPS;
		gid_t group = 0, groups[GROUPS];

		r = getgrouplist(user, group, groups, &ngroups);
		if (r < 0 || ngroups < 0 || ngroups >= GROUPS) {
			printf("r=%d g=%d\n", r, ngroups);
		} else {
			int i;
			for (i = 0; i < ngroups; i++)
				printf("%d ", groups[i]);
		}
#endif

		unsigned int usecs = (round * (unsigned int)tid) % 100000;
		usleep(usecs);
		if (round % 10 == 0)
			putchar('0' + (self % 10));
	}

	printf("[%d] end\n", self);
	pthread_exit(NULL);
}

int main(int argc, char *argv[], char *envp[]) {
	pid_t pid = getpid();
	printf("pid=%d\n", pid);

	unsigned int t;
	for (t = 0; t < ARRAY_SIZE(thread); t++)
		pthread_create(&thread[t], NULL, run, (void *)(long)t);

	int ret = 0;
	void *value_ptr;
	for (t = 0; t < ARRAY_SIZE(thread); t++)
		ret |= pthread_join(thread[t], &value_ptr);

	return ret;
}
/* :!gcc -O0 -g -Wall -lpthread % */