serenity/Userland/cat.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 <AK/Vector.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char** argv)
{
    if (pledge("stdio rpath", nullptr) < 0) {
        perror("pledge");
        return 1;
    }

    Vector<int> fds;
    if (argc > 1) {
        for (int i = 1; i < argc; i++) {
            int fd;
            if ((fd = open(argv[i], O_RDONLY)) == -1) {
                fprintf(stderr, "Failed to open %s: %s\n", argv[i], strerror(errno));
                continue;
            }
            fds.append(fd);
        }
    } else {
        fds.append(0);
    }

    if (pledge("stdio", nullptr) < 0) {
        perror("pledge");
        return 1;
    }

    for (auto& fd : fds) {
        for (;;) {
            char buf[32768];
            ssize_t nread = read(fd, buf, sizeof(buf));
            if (nread == 0)
                break;
            if (nread < 0) {
                perror("read");
                return 2;
            }
            ssize_t nwritten = write(1, buf, nread);
            if (nwritten < 0) {
                perror("write");
                return 3;
            }
            ASSERT(nwritten == nread);
        }
        close(fd);
    }
    return 0;
}