src/bin/lttng/commands/help.c

   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 #include <assert.h>
  14
  15 #include "../command.h"
  16 #include <common/utils.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 NULL
  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, 0, OPT_HELP, 0, 0},
  40         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  41         {0, 0, 0, 0, 0, 0, 0}
  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         char *cmd_name;
  51         static poptContext pc;
  52         const struct cmd_struct *cmd;
  53         int found = 0;
  54         const char *cmd_argv[2];
  55
  56         pc = poptGetContext(NULL, 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         cmd_name = (char *) poptGetArg(pc);
  75
  76         if (cmd_name == NULL) {
  77                 /* Fall back to lttng(1) */
  78                 ret = utils_show_help(1, "lttng", lttng_help_msg);
  79                 if (ret) {
  80                         ERR("Cannot show --help for `lttng`");
  81                         perror("exec");
  82                         ret = CMD_ERROR;
  83                 }
  84
  85                 goto end;
  86         }
  87
  88         /* Help about help? */
  89         if (strcmp(cmd_name, "help") == 0) {
  90                 SHOW_HELP();
  91                 goto end;
  92         }
  93
  94         /* Make sure command name exists */
  95         cmd = &commands[0];
  96
  97         while (cmd->name != NULL) {
  98                 if (strcmp(cmd->name, cmd_name) == 0) {
  99                         found = 1;
 100                         break;
 101                 }
 102
 103                 cmd++;
 104         }
 105
 106         if (!found) {
 107                 ERR("Unknown command \"%s\"", cmd_name);
 108                 ret = CMD_ERROR;
 109                 goto end;
 110         }
 111
 112         /* Show command's help */
 113         cmd_argv[0] = cmd->name;
 114         cmd_argv[1] = "--help";
 115         assert(cmd->func);
 116         ret = cmd->func(2, cmd_argv);
 117
 118 end:
 119         poptFreeContext(pc);
 120         return ret;
 121 }