dabba/help.c

   1 /**
   2  * \file help.c
   3  * \author written by Emmanuel Roullit emmanuel.roullit@gmail.com (c) 2012
   4  * \date 2012
   5  */
   6
   7 /* __LICENSE_HEADER_BEGIN__ */
   8
   9 /*
  10  * Copyright (C) 2012   Emmanuel Roullit <emmanuel.roullit@gmail.com>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or (at
  15  * your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  20  * for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along
  23  * with this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
  25  *
  26  */
  27
  28 /* __LICENSE_HEADER_END__ */
  29
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <errno.h>
  34 #include <getopt.h>
  35 #include <assert.h>
  36 #include <libdabba/macros.h>
  37
  38 static const char dabba_usage_string[] = "dabba [--help] <command> [<args>]\n";
  39 static const char dabba_more_info_string[] =
  40     "See 'dabba help <command>' for more info on a specific command.";
  41
  42 struct cmdname_help {
  43         char name[16];
  44         char help[80];
  45 };
  46
  47 void show_usage(const struct option const *opt)
  48 {
  49         assert(opt);
  50
  51         printf("%s", dabba_usage_string);
  52
  53         if (opt != NULL) {
  54                 while (opt->name != NULL) {
  55                         printf("  --%s", opt->name);
  56                         if (opt->has_arg == required_argument)
  57                                 printf(" <arg>\n");
  58                         else if (opt->has_arg == optional_argument)
  59                                 printf(" [arg]\n");
  60                         else
  61                                 printf("\n");
  62                         opt++;
  63                 }
  64         }
  65 }
  66
  67 static inline void mput_char(char c, uint32_t num)
  68 {
  69         while (num--)
  70                 putchar(c);
  71 }
  72
  73 void help_unknown_cmd(const char const *cmd)
  74 {
  75         assert(cmd);
  76         printf("'%s' is not a dabba command. See 'dabba --help'.\n", cmd);
  77 }
  78
  79 static void list_common_cmds_help(void)
  80 {
  81         size_t i, longest = 0;
  82
  83         static struct cmdname_help common_cmds[] = {
  84                 {"interface", "perform an interface related command"},
  85                 {"capture", "capture live traffic from an interface"}
  86         };
  87
  88         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
  89                 if (longest < strlen(common_cmds[i].name))
  90                         longest = strlen(common_cmds[i].name);
  91         }
  92
  93         printf("The most commonly used dabba commands are:\n");
  94         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
  95                 printf("   %s   ", common_cmds[i].name);
  96                 mput_char(' ', longest - strlen(common_cmds[i].name));
  97                 printf("%s\n", common_cmds[i].help);
  98         }
  99 }
 100
 101 /**
 102  * \brief Print help
 103  * \param[in]           argc            Argument counter
 104  * \param[in]           argv            Argument vector
 105  * \return Returns 0 when the help could be printed, \c errno otherwise
 106  *
 107  * This function prints the basic dabba usage help message.
 108  * Furthermore, it lists all available command.
 109  */
 110
 111 int cmd_help(int argc, const char **argv)
 112 {
 113         char help_name[32];
 114         int rc = 0;
 115
 116         if (argc < 1 || !argv[0]) {
 117                 printf("usage: %s\n\n", dabba_usage_string);
 118                 list_common_cmds_help();
 119                 printf("\n%s\n", dabba_more_info_string);
 120         } else {
 121                 snprintf(help_name, sizeof(help_name), "dabba-%s", argv[0]);
 122                 rc = execlp("man", "man", help_name, (char *)NULL);
 123         }
 124
 125         return rc ? errno : rc;
 126 }