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 <popt.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14 #include "../command.h"
  15 #include <common/utils.h>
  16
  17 #ifdef LTTNG_EMBED_HELP
  18 static const char *help_msg =
  19 #include <lttng-help.1.h>
  20 ;
  21 #endif
  22
  23 static const char *lttng_help_msg =
  24 #ifdef LTTNG_EMBED_HELP
  25 #include <lttng.1.h>
  26 #else
  27 NULL
  28 #endif
  29 ;
  30
  31 enum {
  32         OPT_HELP = 1,
  33         OPT_LIST_OPTIONS,
  34 };
  35
  36 static struct poptOption long_options[] = {
  37         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  38         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  39         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  40         {0, 0, 0, 0, 0, 0, 0}
  41 };
  42
  43 /*
  44  *  cmd_help
  45  */
  46 int cmd_help(int argc, const char **argv, const struct cmd_struct commands[])
  47 {
  48         int opt, ret = CMD_SUCCESS;
  49         char *cmd_name;
  50         static poptContext pc;
  51         const struct cmd_struct *cmd;
  52         int found = 0;
  53         const char *cmd_argv[2];
  54
  55         pc = poptGetContext(NULL, argc, argv, long_options, 0);
  56         poptReadDefaultConfig(pc, 0);
  57
  58         while ((opt = poptGetNextOpt(pc)) != -1) {
  59                 switch (opt) {
  60                 case OPT_HELP:
  61                         SHOW_HELP();
  62                         goto end;
  63                 case OPT_LIST_OPTIONS:
  64                         list_cmd_options(stdout, long_options);
  65                         goto end;
  66                 default:
  67                         ret = CMD_UNDEFINED;
  68                         goto end;
  69                 }
  70         }
  71
  72         /* Get command name */
  73         cmd_name = (char *) poptGetArg(pc);
  74
  75         if (cmd_name == NULL) {
  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(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 != NULL) {
  97                 if (strcmp(cmd->name, cmd_name) == 0) {
  98                         found = 1;
  99                         break;
 100                 }
 101
 102                 cmd++;
 103         }
 104
 105         if (!found) {
 106                 ERR("Unknown command \"%s\"", 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 }