rexec.c

dos下开发TCP网络的库文件部分

/******************************************************************************

    REXEC - remotely execute a UNIX command

    Copyright (C) 1991 Erick Engelke

    This program is free software; you can redistribute it and/or modify
    it, but you may not sell it.

    This program is distributed in the hope that it will be useful,
    but without any warranty; without even the implied warranty of
    merchantability or fitness for a particular purpose.

        Erick Engelke                   or via E-Mail
        Faculty of Engineering
        University of Waterloo          [e-mail]
        200 University Ave.,
        Waterloo, Ont., Canada
        N2L 3G1

******************************************************************************/
#include <stdio.h>
#include <string.h>
#include <time.h>		/* for randomize */
#include <stdlib.h>
#include <conio.h>		/* for getpass */
#include <tcp.h>

#define RSH_PORT 512

char cmdbuf[ 2048 ];
word cmdbuflen;

char lname[ 64 ];		/* local copies if none supplied */
char lpass[ 64 ];
char lcmd[ 255 ];

void makecmdbuf( void *err, char *name, char *pass, char *cmd )
{
    char *p;
err = err;  /* not used */
    p = cmdbuf;
    *p++ = 0;
    strcpy( p, name );
    p = strchr( p, 0 );
    strcpy( ++p, pass );
    p = strchr( p, 0 );
    strcpy( ++p, cmd );
    p = strchr( p, 0 );

    cmdbuflen = (word)(p - cmdbuf) + 1;
}

int rsh( char *hostname, word port, char *name, char *pass, char *cmd )
{
    word lport, jqpublic, count;
    int status;
    longword host;
    char buffer[ 1024 ];
    static tcp_Socket rsh_sock;


    randomize();
    lport = (rand() & 512) + 512;	/* return 511 < port < 1024 */

    if (!(host = resolve( hostname ))) {
	printf("Unable to resolve '%s'\naborting\n", hostname );
	return( 2 );
    }

    jqpublic = 0;
    if ( !name ) {
        printf(" Userid   : ");
	gets( name = lname );
	if ( !*name ) {
	    printf( name = "JQPUBLIC");
	    jqpublic = 1;
	}
    }
    if ( !pass ) {
	if (jqpublic) pass = "";
	else
	    strcpy( pass = lpass, getpass(" Password : "));
	     /* copy for neatness since getpass overwrites */
    }
    if (!cmd) {
        printf(" Command  : ");
        gets( cmd = lcmd );
        if ( !*cmd ) {
            puts("No command given\n");
            exit( 2 );
        }
    }

    makecmdbuf( NULL, name, pass, cmd);

    if (! tcp_open( &rsh_sock, lport, host, port, NULL )) {
	printf("Remote host unaccessible");
	return( 1 );
    }
    fprintf(stderr, "waiting for remote host to connect...\r");
    sock_wait_established( &rsh_sock, sock_delay, NULL, &status );

    fprintf(stderr, "remote host connected, waiting verification...\r");

    sock_write( &rsh_sock, cmdbuf, cmdbuflen );

    while (1) {
	sock_tick( &rsh_sock, &status );
	if (!sock_dataready(&rsh_sock))
	    continue;
	sock_fastread( &rsh_sock, buffer, 1 );
	fprintf(stderr, "                                              \r");
	if ( *buffer == 1 )
	    fprintf(stdout, "RSH failed...\n\r");
	break;
    }

    while (1) {
	if (kbhit())
	    sock_putc( &rsh_sock, getch());
	sock_tick( &rsh_sock, &status );
	if (sock_dataready( &rsh_sock )) {
	    count = sock_fastread( &rsh_sock, buffer, sizeof( buffer ));
	    fwrite( buffer , count, 1, stdout );
	}
    }

sock_err:
    switch (status) {
	case 1 : puts("\nConnection closed");
		 break;
        case-1 : printf("ERROR: %s\n", sockerr( &rsh_sock ));
		 break;
    }
    return( (status == 1) ? 0 : 1 );
}

void help( void )
{
    puts("RSH host [username [password]] cmdstring");
    puts("The values for cmdstring should be placed inside quotes");
    exit( 3 );
}

int main( int argc, char **argv )
{
    char *hostname, *name, *pass, *cmd;

    hostname = name = pass = cmd = NULL;
    sock_init();

    hostname = argv[ 1 ];

    switch ( argc ) {
	case  5 : pass = argv[3];
	case  4 : name = argv[2];
        case  3 : cmd = argv[ argc - 1 ];
                  break;
        case  2 : break;
	default : help();
    }

    exit( rsh( hostname, RSH_PORT, name, pass, cmd ));
    return (0);  /* not reached */
}