140 lines
2.6 KiB
C
140 lines
2.6 KiB
C
/**
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* @brief Provides a PTY over a reverse network socket.
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*
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* Pipes data into and out of a PTY from a TCP socket connected to a remote
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* server.
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*
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* @copyright
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* This file is part of ToaruOS and is released under the terms
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* of the NCSA / University of Illinois License - see LICENSE.md
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* Copyright (C) 2018-2021 K. Lange
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <pty.h>
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#include <sys/wait.h>
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#include <sys/fswait.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <arpa/inet.h>
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int main(int argc, char * argv[]) {
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int fd_master, fd_slave, fd_serial;
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char * user = NULL;
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if (getuid() != 0) {
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fprintf(stderr, "%s: only root can do that\n", argv[0]);
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return 1;
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}
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int opt;
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while ((opt = getopt(argc, argv, "a:")) != -1) {
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switch (opt) {
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case 'a':
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user = optarg;
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break;
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}
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}
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if (optind == argc) {
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fprintf(stderr, "usage: %s remote:port\n", argv[0]);
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return 1;
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}
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char * remotehost = argv[optind];
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char * colon = strstr(remotehost, ":");
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if (!colon) {
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fprintf(stderr, "usage: %s remote:port\n", argv[0]);
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return 1;
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}
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*colon = '\0'; colon++;
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int remoteport = atoi(colon);
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openpty(&fd_master, &fd_slave, NULL, NULL, NULL);
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int sock = socket(AF_INET, SOCK_STREAM, 0);
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if (sock < 0) {
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perror("socket");
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return 1;
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}
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struct hostent * remote = gethostbyname(remotehost);
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if (!remote) {
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perror("gethostbyname");
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return 1;
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}
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struct sockaddr_in addr;
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addr.sin_family = AF_INET;
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memcpy(&addr.sin_addr.s_addr, remote->h_addr, remote->h_length);
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addr.sin_port = htons(remoteport);
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if (connect(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)) < 0) {
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perror("connect");
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return 1;
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}
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fd_serial = sock; //open(file, O_RDWR);
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pid_t child = fork();
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if (!child) {
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setsid();
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dup2(fd_slave, 0);
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dup2(fd_slave, 1);
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dup2(fd_slave, 2);
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system("ttysize -q");
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char * tokens[] = {"/bin/login-loop",NULL,NULL,NULL};
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if (user) {
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tokens[1] = "-f";
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tokens[2] = user;
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}
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execvp(tokens[0], tokens);
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exit(1);
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} else {
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int fds[2] = {fd_serial, fd_master};
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while (1) {
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int index = fswait2(2,fds,200);
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char buf[1024];
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int r;
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switch (index) {
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case 0: /* fd_serial */
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r = read(fd_serial, buf, 1);
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write(fd_master, buf, 1);
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break;
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case 1: /* fd_master */
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r = read(fd_master, buf, 1024);
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write(fd_serial, buf, r);
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break;
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default: /* timeout */
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{
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int result = waitpid(child, NULL, WNOHANG);
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if (result > 0) {
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/* Child login shell has returned (session ended) */
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return 0;
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}
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}
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break;
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}
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}
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}
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return 0;
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}
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