src/bin/lttng/commands/help.c

   1 /*
   2  * Copyright (C) 2015 - Philippe Proulx <pproulx@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <popt.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <assert.h>
  24
  25 #include "../command.h"
  26 #include <common/utils.h>
  27
  28 static const char *help_msg =
  29 #ifdef LTTNG_EMBED_HELP
  30 #include <lttng-help.1.h>
  31 #else
  32 NULL
  33 #endif
  34 ;
  35
  36 static const char *lttng_help_msg =
  37 #ifdef LTTNG_EMBED_HELP
  38 #include <lttng.1.h>
  39 #else
  40 NULL
  41 #endif
  42 ;
  43
  44 enum {
  45         OPT_HELP = 1,
  46         OPT_LIST_OPTIONS,
  47 };
  48
  49 static struct poptOption long_options[] = {
  50         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  51         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  52         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  53         {0, 0, 0, 0, 0, 0, 0}
  54 };
  55
  56 /*
  57  *  cmd_help
  58  */
  59 int cmd_help(int argc, const char **argv, const struct cmd_struct commands[])
  60 {
  61         int opt, ret = CMD_SUCCESS;
  62         char *cmd_name;
  63         static poptContext pc;
  64         const struct cmd_struct *cmd;
  65         int found = 0;
  66         const char *cmd_argv[2];
  67
  68         pc = poptGetContext(NULL, argc, argv, long_options, 0);
  69         poptReadDefaultConfig(pc, 0);
  70
  71         while ((opt = poptGetNextOpt(pc)) != -1) {
  72                 switch (opt) {
  73                 case OPT_HELP:
  74                         SHOW_HELP();
  75                         goto end;
  76                 case OPT_LIST_OPTIONS:
  77                         list_cmd_options(stdout, long_options);
  78                         goto end;
  79                 default:
  80                         ret = CMD_UNDEFINED;
  81                         goto end;
  82                 }
  83         }
  84
  85         /* Get command name */
  86         cmd_name = (char *) poptGetArg(pc);
  87
  88         if (cmd_name == NULL) {
  89                 /* Fall back to lttng(1) */
  90                 ret = utils_show_help(1, "lttng", lttng_help_msg);
  91                 if (ret) {
  92                         ERR("Cannot show --help for `lttng`");
  93                         perror("exec");
  94                         ret = CMD_ERROR;
  95                 }
  96
  97                 goto end;
  98         }
  99
 100         /* Help about help? */
 101         if (strcmp(cmd_name, "help") == 0) {
 102                 SHOW_HELP();
 103                 goto end;
 104         }
 105
 106         /* Make sure command name exists */
 107         cmd = &commands[0];
 108
 109         while (cmd->name != NULL) {
 110                 if (strcmp(cmd->name, cmd_name) == 0) {
 111                         found = 1;
 112                         break;
 113                 }
 114
 115                 cmd++;
 116         }
 117
 118         if (!found) {
 119                 ERR("Unknown command \"%s\"", cmd_name);
 120                 ret = CMD_ERROR;
 121                 goto end;
 122         }
 123
 124         /* Show command's help */
 125         cmd_argv[0] = cmd->name;
 126         cmd_argv[1] = "--help";
 127         assert(cmd->func);
 128         ret = cmd->func(2, cmd_argv);
 129
 130 end:
 131         poptFreeContext(pc);
 132         return ret;
 133 }