help.c

/* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the original program's authors nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <str.h>

#include "config.h"
#include "entry.h"
#include "help.h"
#include "cmds.h"
#include "modules.h"
#include "builtins.h"
#include "errors.h"
#include "util.h"

static const char *cmdname = "help";
extern const char *progname;

#define HELP_IS_COMMANDS        2
#define HELP_IS_MODULE          1
#define HELP_IS_BUILTIN         0
#define HELP_IS_RUBBISH         -1

volatile int mod_switch = -1;

/* Just use a pointer here, no need for mod_switch */
static int is_mod_or_builtin(char *cmd)
{
        int rc = HELP_IS_RUBBISH;

        if (str_cmp(cmd, "commands") == 0)
                return HELP_IS_COMMANDS;

        rc = is_builtin(cmd);
        if (rc > -1) {
                mod_switch = rc;
                return HELP_IS_BUILTIN;
        }
        rc = is_module(cmd);
        if (rc > -1) {
                mod_switch = rc;
                return HELP_IS_MODULE;
        }

        return HELP_IS_RUBBISH;
}

void help_cmd_help(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf(
                "\n  %s [command] <extended>\n"
                "  Use help [command] extended for detailed help on [command] "
                ", even `help'\n\n", cmdname);
        } else {
                printf(
                "\n  `%s' - shows help for commands\n"
                "  Examples:\n"
                "   %s [command]           Show help for [command]\n"
                "   %s [command] extended  Show extended help for [command]\n"
                "\n  If no argument is given to %s, a list of commands are shown\n\n",
                cmdname, cmdname, cmdname, cmdname);
        }

        return;
}

static void help_commands(void)
{
        builtin_t *cmd;
        module_t *mod;
        unsigned int i;

        printf("\n  Bdsh built-in commands:\n");
        printf("  ------------------------------------------------------------\n");

        /* First, show a list of built in commands that are available in this mode */
        for (cmd = builtins; cmd->name != NULL; cmd++, i++) {
                        if (is_builtin_alias(cmd->name))
                                printf("   %-16s\tAlias for `%s'\n", cmd->name,
                                        alias_for_builtin(cmd->name));
                        else
                                printf("   %-16s\t%s\n", cmd->name, cmd->desc);
        }

        i = 0;

        /* Now, show a list of module commands that are available in this mode */
        for (mod = modules; mod->name != NULL; mod++, i++) {
                        if (is_module_alias(mod->name))
                                printf("   %-16s\tAlias for `%s'\n", mod->name,
                                        alias_for_module(mod->name));
                        else
                                printf("   %-16s\t%s\n", mod->name, mod->desc);
        }

        printf("\n  Try %s %s for more information on how `%s' works.\n\n",
                cmdname, cmdname, cmdname);
}

static void help_survival(void)
{
        printf("Don't panic!\n\n");

        printf("This is Bdsh, the Brain dead shell, currently "
            "the primary user interface to HelenOS. Bdsh allows you to enter "
            "commands and supports history (Up, Down arrow keys), "
            "line editing (Left Arrow, Right Arrow, Home, End, Backspace), "
            "selection (Shift + movement keys), copy and paste (Ctrl-C, "
            "Ctrl-V), similar to common desktop environments.\n\n");

        printf("The most basic filesystem commands are Bdsh builtins. Type "
            "'help commands' [Enter] to see the list of Bdsh builtin commands. "
            "Other commands are external executables located in the /app and "
            "/srv directories. Type 'ls /app' [Enter] and 'ls /srv' [Enter] "
            "to see their list. You can execute an external command simply "
            "by entering its name (e.g. type 'tetris' [Enter]).\n\n");

        printf("HelenOS has virtual consoles (VCs). You can switch between "
            "these using the F1-F11 keys.\n\n");

        printf("This is but a small glimpse of what you can do with HelenOS. "
            "To learn more please point your browser to the HelenOS User's "
            "Guide: http://trac.helenos.org/trac.fcgi/wiki/UsersGuide\n\n");
}

int cmd_help(char *argv[])
{
        int rc = 0;
        int argc;
        int level = HELP_SHORT;

        argc = cli_count_args(argv);

        if (argc > 3) {
                printf("\nToo many arguments to `%s', try:\n", cmdname);
                help_cmd_help(HELP_SHORT);
                return CMD_FAILURE;
        }

        if (argc == 3) {
                if (!str_cmp("extended", argv[2]))
                        level = HELP_LONG;
                else
                        level = HELP_SHORT;
        }

        if (argc > 1) {
                rc = is_mod_or_builtin(argv[1]);
                switch (rc) {
                case HELP_IS_RUBBISH:
                        printf("Invalid topic %s\n", argv[1]);
                        return CMD_FAILURE;
                case HELP_IS_COMMANDS:
                        help_commands();
                        return CMD_SUCCESS;
                case HELP_IS_MODULE:
                        help_module(mod_switch, level);
                        return CMD_SUCCESS;
                case HELP_IS_BUILTIN:
                        help_builtin(mod_switch, level);
                        return CMD_SUCCESS;
                }
        }

        help_survival();

        return CMD_SUCCESS;
}

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