mkfile.c

/*
 * Copyright (c) 2009 Jiri Svoboda
 * 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <dirent.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <macros.h>
#include <getopt.h>
#include <stdarg.h>
#include <str.h>
#include <ctype.h>

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

#define BUFFER_SIZE 16384

static const char *cmdname = "mkfile";

static struct option const long_options[] = {
        {"size", required_argument, 0, 's'},
        {"help", no_argument, 0, 'h'},
        {0, 0, 0, 0}
};

void help_cmd_mkfile(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf("`%s' creates a new zero-filled file\n", cmdname);
        } else {
                help_cmd_mkfile(HELP_SHORT);
                printf(
                "Usage:  %s [options] <path>\n"
                "Options:\n"
                "  -h, --help       A short option summary\n"
                "  -s, --size sz    Size of the file\n"
                "\n"
                "Size is a number followed by 'k', 'm' or 'g' for kB, MB, GB.\n"
                "E.g. 100k, 2m, 1g.\n",
                cmdname);
        }

        return;
}

static ssize_t read_size(const char *str)
{
        ssize_t number, unit;
        char *ep;

        number = strtol(str, &ep, 10);
        if (ep[0] == '\0')
                return number;

        if (ep[1] != '\0')
                    return -1;

        switch (tolower(ep[0])) {
        case 'k': unit = 1024; break;
        case 'm': unit = 1024*1024; break;
        case 'g': unit = 1024*1024*1024; break;
        default: return -1;
        }

        return number * unit;
}

int cmd_mkfile(char **argv)
{
        unsigned int argc;
        int c, opt_ind;
        int fd;
        ssize_t file_size;
        ssize_t total_written;
        ssize_t to_write, rc;
        char *file_name;
        void *buffer;

        file_size = 0;

        argc = cli_count_args(argv);

        for (c = 0, optind = 0, opt_ind = 0; c != -1;) {
                c = getopt_long(argc, argv, "s:h", long_options, &opt_ind);
                switch (c) {
                case 'h':
                        help_cmd_mkfile(HELP_LONG);
                        return CMD_SUCCESS;
                case 's':
                        file_size = read_size(optarg);
                        if (file_size < 0) {
                                printf("%s: Invalid file size specification.\n",
                                    cmdname);
                                return CMD_FAILURE;
                        }
                        break;
                }
        }

        argc -= optind;

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

        file_name = argv[optind];

        fd = open(file_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
        if (fd < 0) {
                printf("%s: failed to create file %s.\n", cmdname, file_name);
                return CMD_FAILURE;
        }

        buffer = calloc(BUFFER_SIZE, 1);
        if (buffer == NULL) {
                printf("%s: Error, out of memory.\n", cmdname);
                return CMD_FAILURE;
        }

        total_written = 0;
        while (total_written < file_size) {
                to_write = min(file_size - total_written, BUFFER_SIZE);
                rc = write(fd, buffer, to_write);
                if (rc <= 0) {
                        printf("%s: Error writing file (%zd).\n", cmdname, rc);
                        close(fd);
                        return CMD_FAILURE;
                }
                total_written += rc;
        }

        rc = close(fd);
        if (rc != 0) {
                printf("%s: Error writing file (%zd).\n", cmdname, rc);
                return CMD_FAILURE;
        }

        free(buffer);

        return CMD_SUCCESS;
}

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