source: mainline/uspace/app/bdsh/cmds/modules/cat/cat.c@ 92fd52d7

/* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 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.
 *
 * Neither the name of the original program's authors 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 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 OWNER 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 <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <string.h>
#include <fcntl.h>

#include "config.h"
#include "util.h"
#include "errors.h"
#include "entry.h"
#include "cat.h"
#include "cmds.h"

static char *cmdname = "cat";
#define CAT_VERSION "0.0.1"
#define CAT_DEFAULT_BUFLEN 1024

static char *cat_oops = "That option is not yet supported\n";

static struct option const long_options[] = {
        { "help", no_argument, 0, 'h' },
        { "version", no_argument, 0, 'v' },
        { "head", required_argument, 0, 'H' },
        { "tail", required_argument, 0, 't' },
        { "buffer", required_argument, 0, 'b' },
        { "more", no_argument, 0, 'm' },
        { 0, 0, 0, 0 }
};

/* Dispays help for cat in various levels */
void help_cmd_cat(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf("`%s' shows the contents of files\n", cmdname);
        } else {
                help_cmd_cat(HELP_SHORT);
                printf(
                "Usage:  %s [options] <file1> [file2] [...]\n"
                "Options:\n"
                "  -h, --help       A short option summary\n"
                "  -v, --version    Print version information and exit\n"
                "  -H, --head ##    Print only the first ## bytes\n"
                "  -t, --tail ##    Print only the last ## bytes\n"
                "  -b, --buffer ##  Set the read buffer size to ##\n"
                "  -m, --more       Pause after each screen full\n"
                "Currently, %s is under development, some options don't work.\n",
                cmdname, cmdname);
        }

        return;
}

static unsigned int cat_file(const char *fname, size_t blen)
{
        int fd, bytes = 0, count = 0, reads = 0;
        off_t total = 0;
        char *buff = NULL;

        if (-1 == (fd = open(fname, O_RDONLY))) {
                printf("Unable to open %s\n", fname);
                return 1;
        }

        total = lseek(fd, 0, SEEK_END);
        lseek(fd, 0, SEEK_SET);

        if (NULL == (buff = (char *) malloc(blen + 1))) {
                close(fd);
                printf("Unable to allocate enough memory to read %s\n",
                        fname);
                return 1;
        }

        do {
                bytes = read(fd, buff, blen);
                if (bytes > 0) {
                        count += bytes;
                        buff[bytes] = '\0';
                        printf("%s", buff);
                        reads++;
                }
        } while (bytes > 0);

        close(fd);
        if (bytes == -1) {
                printf("Error reading %s\n", fname);
                free(buff);
                return 1;
        }

        free(buff);

        return 0;
}

/* Main entry point for cat, accepts an array of arguments */
int cmd_cat(char **argv)
{
        unsigned int argc, i, ret = 0, buffer = 0;
        int c, opt_ind;

        argc = cli_count_args(argv);

        for (c = 0, optind = 0, opt_ind = 0; c != -1;) {
                c = getopt_long(argc, argv, "hvmH:t:b:", long_options, &opt_ind);
                switch (c) {
                case 'h':
                        help_cmd_cat(HELP_LONG);
                        return CMD_SUCCESS;
                case 'v':
                        printf("%s\n", CAT_VERSION);
                        return CMD_SUCCESS;
                case 'H':
                        printf(cat_oops);
                        return CMD_FAILURE;
                case 't':
                        printf(cat_oops);
                        return CMD_FAILURE;
                case 'b':
                        printf(cat_oops);
                        break;
                case 'm':
                        printf(cat_oops);
                        return CMD_FAILURE;
                }
        }

        argc -= optind;

        if (argc < 1) {
                printf("%s - incorrect number of arguments. Try `%s --help'\n",
                        cmdname, cmdname);
                return CMD_FAILURE;
        }

        if (buffer <= 0)
                buffer = CAT_DEFAULT_BUFLEN;

        for (i = optind; argv[i] != NULL; i++)
                ret += cat_file(argv[i], buffer);

        if (ret)
                return CMD_FAILURE;
        else
                return CMD_SUCCESS;
}