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  1. /* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
  2.  * All rights reserved.
  3.  *
  4.  * Redistribution and use in source and binary forms, with or without
  5.  * modification, are permitted provided that the following conditions are met:
  6.  *
  7.  * Redistributions of source code must retain the above copyright notice, this
  8.  * list of conditions and the following disclaimer.
  9.  *
  10.  * Redistributions in binary form must reproduce the above copyright notice,
  11.  * this list of conditions and the following disclaimer in the documentation
  12.  * and/or other materials provided with the distribution.
  13.  *
  14.  * Neither the name of the original program's authors nor the names of its
  15.  * contributors may be used to endorse or promote products derived from this
  16.  * software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19.  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21.  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22.  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23.  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24.  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25.  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26.  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27.  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28.  * POSSIBILITY OF SUCH DAMAGE.
  29.  */
  30.  
  31. #include <stdio.h>
  32. #include <stdlib.h>
  33. #include <unistd.h>
  34. #include <getopt.h>
  35. #include <string.h>
  36. #include <fcntl.h>
  37.  
  38. #include "config.h"
  39. #include "util.h"
  40. #include "errors.h"
  41. #include "entry.h"
  42. #include "cat.h"
  43. #include "cmds.h"
  44.  
  45. static char *cmdname = "cat";
  46. #define CAT_VERSION "0.0.1"
  47. #define CAT_DEFAULT_BUFLEN 1024
  48.  
  49. static char *cat_oops = "That option is not yet supported\n";
  50.  
  51. static struct option const long_options[] = {
  52.     { "help", no_argument, 0, 'h' },
  53.     { "version", no_argument, 0, 'v' },
  54.     { "head", required_argument, 0, 'H' },
  55.     { "tail", required_argument, 0, 't' },
  56.     { "buffer", required_argument, 0, 'b' },
  57.     { "more", no_argument, 0, 'm' },
  58.     { 0, 0, 0, 0 }
  59. };
  60.  
  61. /* Dispays help for cat in various levels */
  62. void * help_cmd_cat(unsigned int level)
  63. {
  64.     if (level == HELP_SHORT) {
  65.         printf("`%s' shows the contents of files\n", cmdname);
  66.     } else {
  67.         help_cmd_cat(HELP_SHORT);
  68.         printf(
  69.         "Usage:  %s [options] <file1> [file2] [...]\n"
  70.         "Options:\n"
  71.         "  -h, --help       A short option summary\n"
  72.         "  -v, --version    Print version information and exit\n"
  73.         "  -H, --head ##    Print only the first ## bytes\n"
  74.         "  -t, --tail ##    Print only the last ## bytes\n"
  75.         "  -b, --buffer ##  Set the read buffer size to ##\n"
  76.         "  -m, --more       Pause after each screen full\n"
  77.         "Currently, %s is under development, some options don't work.\n",
  78.         cmdname, cmdname);
  79.     }
  80.  
  81.     return CMD_VOID;
  82. }
  83.  
  84. static unsigned int cat_file(const char *fname, size_t blen)
  85. {
  86.     int fd, bytes = 0, count = 0, reads = 0;
  87.     off_t total = 0;
  88.     char *buff = NULL;
  89.  
  90.     if (-1 == (fd = open(fname, O_RDONLY))) {
  91.         printf("Unable to open %s\n", fname);
  92.         return 1;
  93.     }
  94.  
  95.     total = lseek(fd, 0, SEEK_END);
  96.     lseek(fd, 0, SEEK_SET);
  97.  
  98.     if (NULL == (buff = (char *) malloc(blen + 1))) {
  99.         close(fd);
  100.         printf("Unable to allocate enough memory to read %s\n",
  101.             fname);
  102.         return 1;
  103.     }
  104.  
  105.     do {
  106.         memset(buff, 0, sizeof(buff));
  107.         bytes = read(fd, buff, blen);
  108.         if (bytes > 0) {
  109.             count += bytes;
  110.             if (bytes < blen)
  111.                 buff[bytes] = '\0';
  112.             printf(buff);
  113.             reads++;
  114.         }
  115.     } while (bytes > 0);
  116.  
  117.     close(fd);
  118.     if (bytes == -1) {
  119.         printf("Error reading %s\n", fname);
  120.         free(buff);
  121.         return 1;
  122.     }
  123.  
  124.     /* Debug stuff, newline not added purposefully */
  125.     printf("** %s is a file with the size of %ld bytes\n",
  126.         fname, total);
  127.     printf( "** %d bytes were read in a buffer of %d bytes in %d reads\n",
  128.         count, blen, reads);
  129.     printf("** Read %s\n", count == total ? "Succeeded" : "Failed");
  130.     free(buff);
  131.  
  132.     return 0;
  133. }
  134.  
  135. /* Main entry point for cat, accepts an array of arguments */
  136. int * cmd_cat(char **argv)
  137. {
  138.     unsigned int argc, i, ret = 0, buffer = 0;
  139.     int c, opt_ind;
  140.  
  141.     for (argc = 0; argv[argc] != NULL; argc ++);
  142.  
  143.     for (c = 0, optind = 0, opt_ind = 0; c != -1;) {
  144.         c = getopt_long(argc, argv, "hvmH:t:b:", long_options, &opt_ind);
  145.         switch (c) {
  146.         case 'h':
  147.             help_cmd_cat(HELP_LONG);
  148.             return CMD_SUCCESS;
  149.         case 'v':
  150.             printf("%s\n", CAT_VERSION);
  151.             return CMD_SUCCESS;
  152.         case 'H':
  153.             printf(cat_oops);
  154.             return CMD_FAILURE;
  155.         case 't':
  156.             printf(cat_oops);
  157.             return CMD_FAILURE;
  158.         case 'b':
  159.             printf(cat_oops);
  160.             break;
  161.         case 'm':
  162.             printf(cat_oops);
  163.             return CMD_FAILURE;
  164.         }
  165.     }
  166.  
  167.     argc -= optind;
  168.  
  169.     if (argc < 1) {
  170.         printf("%s - incorrect number of arguments. Try `%s --help'\n",
  171.             cmdname, cmdname);
  172.         return CMD_FAILURE;
  173.     }
  174.  
  175.     if (buffer <= 0)
  176.         buffer = CAT_DEFAULT_BUFLEN;
  177.  
  178.     for (i = optind; argv[i] != NULL; i++)
  179.         ret += cat_file(argv[i], buffer);
  180.  
  181.     if (ret)
  182.         return CMD_FAILURE;
  183.     else
  184.         return CMD_SUCCESS;
  185. }
  186.  
  187.