bad_lseek.c

/*
 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
 *      The President and Fellows of Harvard College.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY 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 UNIVERSITY 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.
 */

/*
 * lseek
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <err.h>

#include "config.h"
#include "test.h"

static
void
lseek_fd_device(void)
{
        int fd, rv;

        fd = open("null:", O_RDONLY);
        if (fd<0) {
                warn("UH-OH: opening null: failed");
                return;
        }

        rv = lseek(fd, 309, SEEK_SET);
        report_test(rv, errno, ESPIPE, "lseek on device");

        close(fd);
}

static
void
lseek_file_stdin(void)
{
        int fd, fd2, rv, status;
        const char slogan[] = "There ain't no such thing as a free lunch";
        size_t len = strlen(slogan);
        pid_t pid;

        /* fork so we don't affect our own stdin */
        pid = fork();
        if (pid<0) {
                warn("UH-OH: fork failed");
                return;
        }
        else if (pid!=0) {
                /* parent */
                rv = waitpid(pid, &status, 0);
                if (rv<0) {
                        warn("UH-OH: waitpid failed");
                }
                if (WIFSIGNALED(status)) {
                        warn("UH-OH: subprocess exited with signal %d",
                             WTERMSIG(status));
                }
                else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
                        warn("UH-OH: subprocess exited with code %d",
                             WEXITSTATUS(status));
                }
                return;
        }

        /* child */

        fd = open_testfile(NULL);
        if (fd<0) {
                _exit(0);
        }

        /* 
         * Move file to stdin.
         * Use stdin (rather than stdout or stderr) to maximize the
         * chances of detecting any special-case handling of fds 0-2.
         * (Writing to stdin is fine as long as it's open for write,
         * and it will be.)
         */
        fd2 = dup2(fd, STDIN_FILENO);
        if (fd2<0) {
                warn("UH-OH: dup2 to stdin failed");
                close(fd);
                remove(TESTFILE);
                _exit(0);
        }
        if (fd2 != STDIN_FILENO) {
                warn("UH-OH: dup2 returned wrong file handle");
                close(fd);
                remove(TESTFILE);
                _exit(0);
        }
        close(fd);

        rv = write(STDIN_FILENO, slogan, len);
        if (rv<0) {
                warn("UH-OH: write to %s (via stdin) failed", TESTFILE);
                remove(TESTFILE);
                _exit(0);
        }

        if ((unsigned)rv != len) {
                warnx("UH-OH: write to %s (via stdin) got short count",
                      TESTFILE);
                remove(TESTFILE);
                _exit(0);
        }

        rv = lseek(STDIN_FILENO, 0, SEEK_SET);
        report_test(rv, errno, 0, "lseek stdin when open on file (try 1)");

        rv = lseek(STDIN_FILENO, 0, SEEK_END);
        report_test(rv, errno, 0, "lseek stdin when open on file (try 2)");

        remove(TESTFILE);
        _exit(0);
}

static
void
lseek_loc_negative(void)
{
        int fd, rv;

        fd = open_testfile(NULL);
        if (fd<0) {
                return;
        }

        rv = lseek(fd, -309, SEEK_SET);
        report_test(rv, errno, EINVAL, "lseek to negative offset");

        close(fd);
        remove(TESTFILE);
}

static
void
lseek_whence_inval(void)
{
        int fd, rv;

        fd = open_testfile(0);
        if (fd<0) {
                return;
        }

        rv = lseek(fd, 0, 3594);
        report_test(rv, errno, EINVAL, "lseek with invalid whence code");

        close(fd);
        remove(TESTFILE);
}

static
void
lseek_loc_pasteof(void)
{
        const char *message = "blahblah";
        int fd;
        off_t pos;

        fd = open_testfile(message);
        if (fd<0) {
                return;
        }

        pos = lseek(fd, 5340, SEEK_SET);
        if (pos == -1) {
                warn("FAILURE: lseek past EOF failed");
                goto out;
        }
        if (pos != 5340) {
                warnx("FAILURE: lseek to 5340 got offset %ld", (long) pos);
                goto out;
        }

        pos = lseek(fd, -50, SEEK_CUR);
        if (pos == -1) {
                warn("FAILURE: small seek beyond EOF failed");
                goto out;
        }
        if (pos != 5290) {
                warnx("FAILURE: SEEK_CUR to 5290 got offset %ld", (long) pos);
                goto out;
        }

        pos = lseek(fd, 0, SEEK_END);
        if (pos == -1) {
                warn("FAILURE: seek to EOF failed");
                goto out;
        }

        if (pos != (off_t) strlen(message)) {
                warnx("FAILURE: seek to EOF got %ld (should be %d)", 
                      (long) pos, strlen(message));
                goto out;
        }

        warnx("passed: seek past/to EOF");

    out:
        close(fd);
        remove(TESTFILE);
        return;
}

void
test_lseek(void)
{
        test_lseek_fd();

        lseek_fd_device();
        lseek_file_stdin();
        lseek_loc_negative();
        lseek_loc_pasteof();
        lseek_whence_inval();
}