/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2024 Bill Sommerfeld <sommerfeld@hamachi.org>
 */

/*
 * Regression test for illumos bug #16352: verify that strftime behaves
 * properly if the buffer length is overly large.
 */

#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

static int status = EXIT_SUCCESS;

static const char expected_buf[] = "2024 04 23";
static int expected_ret = 10;

static void
check_results(const char *name, int ret, const char *buf)
{
        if (ret == 0) {
                fprintf(stderr, "TEST FAILED: %s returned 0\n", name);
                status = EXIT_FAILURE;
        }

        if (ret != 10) {
                fprintf(stderr, "TEST FAILED: %s length %d (expected %d)\n",
                    name, ret, expected_ret);
                status = EXIT_FAILURE;
        }

        if (strcmp(buf, expected_buf) != 0) {
                fprintf(stderr, "TEST FAILED: %s contents [%s]"
                    " (expected [%s])\n", name, buf, expected_buf);
                status = EXIT_FAILURE;
        }
}

int
main(void)
{
        int ret;
        struct tm t;
        char buf[1024];

        memset(&t, 0, sizeof (t));
        t.tm_year = 124;
        t.tm_mon = 3;
        t.tm_mday = 23;

        /*
         * Test that ascftime() behaves properly; ascftime calls
         * strftime(buf, LONG_MAX, format, t).  For an unfixed libc,
         * this will fail if buf lies above the midpoint of the
         * process address space, as the computation of buf + len
         * overflows and wraps around.
         */
        ret = ascftime(buf, "%Y %m %d", &t);
        check_results("ascftime", ret, buf);

        /*
         * Repeat test with strftime passed the maximum possible length.
         * This will wrap around as long as buf is not NULL, letting us
         * exercise the fix even if the user address space is restricted
         * in some way.
         */
        ret = strftime(buf, ULONG_MAX, "%Y %m %d", &t);
        check_results("strftime", ret, buf);

        if (status == EXIT_SUCCESS) {
                (void) printf("TEST PASSED: observed expected output\n");
        }
        printf("NOTE: buffer is %p\n", buf);
        return (status);
}