/*      $NetBSD: t_fflush.c,v 1.2 2025/12/18 17:09:58 christos Exp $ */

/*-
 * Copyright (c) 2011 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jukka Ruohonen.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__RCSID("$NetBSD: t_fflush.c,v 1.2 2025/12/18 17:09:58 christos Exp $");

#include <atf-c.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>

static const char *path = "fflush";

ATF_TC_WITH_CLEANUP(fflush_err);
ATF_TC_HEAD(fflush_err, tc)
{
        atf_tc_set_md_var(tc, "descr", "Test errors from fflush(3)");
}

ATF_TC_BODY(fflush_err, tc)
{
        FILE *f;

        f = fopen(path, "w");

        ATF_REQUIRE(f != NULL);
        ATF_REQUIRE(fflush(NULL) == 0); /* all files */
        ATF_REQUIRE(fflush(f) == 0);    /* this file */
        ATF_REQUIRE(fclose(f) == 0);

        /* Should fail on closed fp's, but really undefined behavior */
        errno = 0;
        ATF_REQUIRE_ERRNO(EBADF, fflush(f) == EOF);

        (void)unlink(path);
}

ATF_TC_CLEANUP(fflush_err, tc)
{
        (void)unlink(path);
}

ATF_TC_WITH_CLEANUP(fflush_seek);
ATF_TC_HEAD(fflush_seek, tc)
{
        atf_tc_set_md_var(tc, "descr", "Test file offsets with fflush(3)");
}

ATF_TC_BODY(fflush_seek, tc)
{
        char buf[12];
        int fd = -1;
        FILE *f;

        /*
         * IEEE Std 1003.1-2008:
         *
         * "For a stream open for reading, if the file
         *  is not already at EOF, and the file is one
         *  capable of seeking, the file offset of the
         *  underlying open file description shall be
         *  adjusted so that the next operation on the
         *  open file description deals with the byte
         *  after the last one read from or written to
         *  the stream being flushed."
         */
        f = fopen(path, "w");
        ATF_REQUIRE(f != NULL);

        ATF_REQUIRE(fwrite("garbage", 1, 7, f) == 7);
        ATF_REQUIRE(fclose(f) == 0);

        f = fopen(path, "r+");
        ATF_REQUIRE(f != NULL);

        fd = fileno(f);
        ATF_REQUIRE(fd != -1);

        ATF_REQUIRE(fread(buf, 1, 3, f) == 3);
        ATF_REQUIRE(fflush(f) == 0);
        ATF_REQUIRE(fseek(f, 0, SEEK_CUR) == 0);

        /*
         * Verify that the offsets are right and that
         * a read operation resumes at the correct location.
         */
        ATF_REQUIRE(ftell(f) == 3);
        ATF_REQUIRE(lseek(fd, 0, SEEK_CUR) == 3);
        ATF_REQUIRE(fgetc(f) == 'b');

        ATF_REQUIRE(fclose(f) == 0);
        ATF_REQUIRE(unlink(path) == 0);
}

ATF_TC_CLEANUP(fflush_seek, tc)
{
        (void)unlink(path);
}

ATF_TC(fflush_ro);
ATF_TC_HEAD(fflush_ro, tc)
{
        atf_tc_set_md_var(tc, "descr", "Test fflush(3) with read-only file");
}

ATF_TC_BODY(fflush_ro, tc)
{
        FILE *f;
        char p;

        f = fopen("/dev/null", "r");
        ATF_REQUIRE(f != NULL);

        ATF_REQUIRE(fread(&p, 1, 1, f) == 0);
        ATF_REQUIRE(fflush(f) == 0);
        ATF_REQUIRE(fclose(f) == 0);
}

ATF_TC_WITH_CLEANUP(fpurge_err);
ATF_TC_HEAD(fpurge_err, tc)
{
        atf_tc_set_md_var(tc, "descr", "Test errors from fpurge(3)");
}

ATF_TC_BODY(fpurge_err, tc)
{
        FILE *f;

        f = fopen(path, "w");
        ATF_REQUIRE(f != NULL);
        ATF_REQUIRE(fclose(f) == 0);

        errno = 0;
        ATF_REQUIRE_ERRNO(EBADF, fpurge(f) == EOF);

        (void)unlink(path);
}

ATF_TC_CLEANUP(fpurge_err, tc)
{
        (void)unlink(path);
}
ATF_TP_ADD_TCS(tp)
{

        ATF_TP_ADD_TC(tp, fflush_err);
        ATF_TP_ADD_TC(tp, fflush_seek);
        ATF_TP_ADD_TC(tp, fflush_ro);
        ATF_TP_ADD_TC(tp, fpurge_err);

        return atf_no_error();
}