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 #ifdef LTTNG_EMBED_HELP
  29 static const char *help_msg =
  30 #include <lttng-help.1.h>
  31 ;
  32 #endif
  33
  34 static const char *lttng_help_msg =
  35 #ifdef LTTNG_EMBED_HELP
  36 #include <lttng.1.h>
  37 #else
  38 NULL
  39 #endif
  40 ;
  41
  42 enum {
  43         OPT_HELP = 1,
  44         OPT_LIST_OPTIONS,
  45 };
  46
  47 static struct poptOption long_options[] = {
  48         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  49         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  50         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  51         {0, 0, 0, 0, 0, 0, 0}
  52 };
  53
  54 /*
  55  *  cmd_help
  56  */
  57 int cmd_help(int argc, const char **argv, const struct cmd_struct commands[])
  58 {
  59         int opt, ret = CMD_SUCCESS;
  60         char *cmd_name;
  61         static poptContext pc;
  62         const struct cmd_struct *cmd;
  63         int found = 0;
  64         const char *cmd_argv[2];
  65
  66         pc = poptGetContext(NULL, argc, argv, long_options, 0);
  67         poptReadDefaultConfig(pc, 0);
  68
  69         while ((opt = poptGetNextOpt(pc)) != -1) {
  70                 switch (opt) {
  71                 case OPT_HELP:
  72                         SHOW_HELP();
  73                         goto end;
  74                 case OPT_LIST_OPTIONS:
  75                         list_cmd_options(stdout, long_options);
  76                         goto end;
  77                 default:
  78                         ret = CMD_UNDEFINED;
  79                         goto end;
  80                 }
  81         }
  82
  83         /* Get command name */
  84         cmd_name = (char *) poptGetArg(pc);
  85
  86         if (cmd_name == NULL) {
  87                 /* Fall back to lttng(1) */
  88                 ret = utils_show_help(1, "lttng", lttng_help_msg);
  89                 if (ret) {
  90                         ERR("Cannot show --help for `lttng`");
  91                         perror("exec");
  92                         ret = CMD_ERROR;
  93                 }
  94
  95                 goto end;
  96         }
  97
  98         /* Help about help? */
  99         if (strcmp(cmd_name, "help") == 0) {
 100                 SHOW_HELP();
 101                 goto end;
 102         }
 103
 104         /* Make sure command name exists */
 105         cmd = &commands[0];
 106
 107         while (cmd->name != NULL) {
 108                 if (strcmp(cmd->name, cmd_name) == 0) {
 109                         found = 1;
 110                         break;
 111                 }
 112
 113                 cmd++;
 114         }
 115
 116         if (!found) {
 117                 ERR("Unknown command \"%s\"", cmd_name);
 118                 ret = CMD_ERROR;
 119                 goto end;
 120         }
 121
 122         /* Show command's help */
 123         cmd_argv[0] = cmd->name;
 124         cmd_argv[1] = "--help";
 125         assert(cmd->func);
 126         ret = cmd->func(2, cmd_argv);
 127
 128 end:
 129         poptFreeContext(pc);
 130         return ret;
 131 }