src/bin/lttng/commands/help.cpp

   1 /*
   2  * Copyright (C) 2015 Philippe Proulx <pproulx@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include "../command.hpp"
  10
  11 #include <common/utils.hpp>
  12
  13 #include <popt.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17
  18 #ifdef LTTNG_EMBED_HELP
  19 static const char *help_msg =
  20 #include <lttng-help.1.h>
  21         ;
  22 #endif
  23
  24 static const char *lttng_help_msg =
  25 #ifdef LTTNG_EMBED_HELP
  26 #include <lttng.1.h>
  27 #else
  28         nullptr
  29 #endif
  30         ;
  31
  32 enum {
  33         OPT_HELP = 1,
  34         OPT_LIST_OPTIONS,
  35 };
  36
  37 static struct poptOption long_options[] = {
  38         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  39         { "help", 'h', POPT_ARG_NONE, nullptr, OPT_HELP, nullptr, nullptr },
  40         { "list-options", 0, POPT_ARG_NONE, nullptr, OPT_LIST_OPTIONS, nullptr, nullptr },
  41         { nullptr, 0, 0, nullptr, 0, nullptr, nullptr }
  42 };
  43
  44 /*
  45  *  cmd_help
  46  */
  47 int cmd_help(int argc, const char **argv, const struct cmd_struct commands[])
  48 {
  49         int opt, ret = CMD_SUCCESS;
  50         const char *arg_cmd_name;
  51         static poptContext pc;
  52         const struct cmd_struct *cmd;
  53         bool found = false;
  54         const char *cmd_argv[2];
  55
  56         pc = poptGetContext(nullptr, argc, argv, long_options, 0);
  57         poptReadDefaultConfig(pc, 0);
  58
  59         while ((opt = poptGetNextOpt(pc)) != -1) {
  60                 switch (opt) {
  61                 case OPT_HELP:
  62                         SHOW_HELP();
  63                         goto end;
  64                 case OPT_LIST_OPTIONS:
  65                         list_cmd_options(stdout, long_options);
  66                         goto end;
  67                 default:
  68                         ret = CMD_UNDEFINED;
  69                         goto end;
  70                 }
  71         }
  72
  73         /* Get command name */
  74         arg_cmd_name = poptGetArg(pc);
  75         if (arg_cmd_name == nullptr) {
  76                 /* Fall back to lttng(1) */
  77                 ret = utils_show_help(1, "lttng", lttng_help_msg);
  78                 if (ret) {
  79                         ERR("Cannot show --help for `lttng`");
  80                         perror("exec");
  81                         ret = CMD_ERROR;
  82                 }
  83
  84                 goto end;
  85         }
  86
  87         /* Help about help? */
  88         if (strcmp(arg_cmd_name, "help") == 0) {
  89                 SHOW_HELP();
  90                 goto end;
  91         }
  92
  93         /* Make sure command name exists */
  94         cmd = &commands[0];
  95
  96         while (cmd->name != nullptr) {
  97                 if (strcmp(cmd->name, arg_cmd_name) == 0) {
  98                         found = true;
  99                         break;
 100                 }
 101
 102                 cmd++;
 103         }
 104
 105         if (!found) {
 106                 ERR("Unknown command \"%s\"", arg_cmd_name);
 107                 ret = CMD_ERROR;
 108                 goto end;
 109         }
 110
 111         /* Show command's help */
 112         cmd_argv[0] = cmd->name;
 113         cmd_argv[1] = "--help";
 114         LTTNG_ASSERT(cmd->func);
 115         ret = cmd->func(2, cmd_argv);
 116
 117 end:
 118         poptFreeContext(pc);
 119         return ret;
 120 }