#include <sys/sysctl.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

static void
test_fread(void)
{
	static uint8_t buf[128];
	FILE *f;

	if ((f = fopen("/dev/urandom", "rb")) == NULL)
		err(1, "fopen");
	if (fread(buf, 1, sizeof buf, f) != sizeof buf)
		err(1, "fread");
	if (fclose(f) == EOF)
		err(1, "fclose");
}

static void
test_fread_setbuf(void)
{
	static uint8_t buf[128];
	FILE *f;

	if ((f = fopen("/dev/urandom", "rb")) == NULL)
		err(1, "fopen");
	setbuf(f, NULL);
	if (fread(buf, 1, sizeof buf, f) != sizeof buf)
		err(1, "fread");
	if (fclose(f) == EOF)
		err(1, "fclose");
}

static void
test_fread_block(void)
{
	static uint8_t buf[128];
	FILE *f;

	if ((f = fopen("/dev/urandom", "rb")) == NULL)
		err(1, "fopen");
	if (fread(buf, sizeof buf, 1, f) != 1)
		err(1, "fread");
	if (fclose(f) == EOF)
		err(1, "fclose");
}

static void
test_fread_setbuf_block(void)
{
	static uint8_t buf[128];
	FILE *f;

	if ((f = fopen("/dev/urandom", "rb")) == NULL)
		err(1, "fopen");
	setbuf(f, NULL);
	if (fread(buf, sizeof buf, 1, f) != 1)
		err(1, "fread");
	if (fclose(f) == EOF)
		err(1, "fclose");
}

static void
test_read(void)
{
	static uint8_t buf[128];
	int fd;
	ssize_t nread;

	if ((fd = open("/dev/urandom", O_RDONLY)) == -1)
		err(1, "open");
	if ((nread = read(fd, buf, sizeof buf)) == -1)
		err(1, "read");
	if ((size_t)nread != sizeof buf)
		errx(1, "truncated read: %zu", (size_t)nread);
	if (close(fd) == -1)
		err(1, "close");
}

static void
test_arnd(void)
{
	static uint8_t buf[128];
	size_t len = sizeof buf;

	if (sysctl((const int[]){CTL_KERN, KERN_ARND}, 2, buf, &len, NULL, 0)
	    == -1)
		err(1, "sysctl kern.arandom");
	if (len != 128)
		err(1, "truncated");
}

static void __noinline
do_test(void (*test)(void))
{
	(*test)();
}

int
main(void)
{
	static const struct {
		const char *name;
		void (*test)(void);
	} T[] = {
		{ "fread", test_fread },
		{ "fread_setbuf", test_fread_setbuf },
		{ "fread_block", test_fread_block },
		{ "fread_setbuf_block", test_fread_setbuf_block },
		{ "read", test_read },
		{ "arnd", test_arnd },
	};
	struct timespec diff;
	unsigned i, j;

#if 0
	for (i = 0; i < sizeof(T)/sizeof(T[0]); i++)
		T[i].test();	/* prime */
#endif

	if (clock_gettime(CLOCK_MONOTONIC, &diff))
		err(1, "clock_gettime");

	for (i = 0; i < sizeof(T)/sizeof(T[0]); i++) {
		if (strcmp(T[i].name, "fread") != 0)
			continue;
		printf("%18s ", T[i].name);
		do_test(T[i].test);
		for (j = 0; j < 3; j++) {
			struct timespec start, end;

			if (clock_gettime(CLOCK_MONOTONIC, &start))
				err(1, "clock_gettime");
			do_test(T[i].test);
			if (clock_gettime(CLOCK_MONOTONIC, &end))
				err(1, "clock_gettime");

			timespecsub(&end, &start, &diff);
			printf(" %9"PRIdMAX".%09lu",
			    (intmax_t)diff.tv_sec, diff.tv_nsec);
		}
		printf("\n");
	}

	fflush(stdout);
	return ferror(stdout);
}