Desktop/xinu_mips-1.0.2.tar/xinu_mips-1.0.2/shell/xsh_help.c

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/* Embedded XINU, Copyright (C) 2007.  All rights reserved. */

#include <kernel.h>
#include <shell.h>
#include <stdio.h>
#include <string.h>

command xsh_help(ushort stdin, ushort stdout, ushort stderr,
                 ushort nargs, char *args[])
{
        uchar i;
        char *command_args[2]; /* temporary storage for [command] --help */

        /* Output help, if '--help' argument was supplied */
        if (nargs == 2 && strncmp(args[1],"--help",6) == 0) 
        {
                fprintf(stdout, "Usage: help [command]\n");
                fprintf(stdout, "Provides a list of commands for the shell.\n");
                fprintf(stdout, "If command is provided, help information will ");
                fprintf(stdout, "be provided for the specified command; equivalent ");
                fprintf(stdout, "to entering 'command --help' into the shell.\n");
                fprintf(stdout, "\t--help\t display this help and exit\n");
                return OK;
        }

        /* Check for correct number of arguments */
        if (nargs > 2) 
        {
                fprintf(stderr, "help: too many arguments\n");
                fprintf(stderr, "Try 'help --help' for more information.\n");
                return SYSERR;
        }

        /* Output help for specific command, if 'command' argument was supplied */
        if (nargs == 2)
        {
                for ( i = 0; i < ncommand; i++)
                {
                        if (strncmp(args[1],commandtab[i].name,6) == 0)
                        {
                                command_args[0] = args[2];
                                command_args[1] = "--help";
                                (*commandtab[i].procedure)(stdin, stdout, stderr,
                                                           2, command_args);
                                return OK;
                        }
                }
                fprintf(stdout, "help: no help topics match '%s'.  Try 'help --help'");
                fprintf(stdout, "for more information.\n");
                return SYSERR;
        }

        /* Output command list */
        fprintf(stdout, "Shell Commands:\n");
        for( i = 0; i < ncommand; i++)
        { fprintf(stdout, "\t%s\n", commandtab[i].name); }

        return OK;
}

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