convert for inetd

[unix-history] / usr / src / libexec / rshd / rshd.c

#ifndef lint
static char sccsid[] = "@(#)rshd.c      4.18 (Berkeley) 84/04/11";
#endif

#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/wait.h>

#include <netinet/in.h>

#include <stdio.h>
#include <errno.h>
#include <pwd.h>
#include <signal.h>
#include <netdb.h>

int     errno;
int     reapchild();
struct  sockaddr_in sin = { AF_INET };
struct  passwd *getpwnam();
char    *index(), *rindex(), *sprintf();
int     options;
/* VARARGS 1 */
int     error();
/*
* remote shell server:
*      remuser\0
*      locuser\0
*      command\0
*      data
*/
main(argc, argv)
       int argc;
       char **argv;
{
       int f, linger;
       struct sockaddr_in from;
       struct servent *sp;

       sp = getservbyname("shell", "tcp");
       if (sp == 0) {
               fprintf(stderr, "rshd: tcp/shell: unknown service\n");
               exit(1);
       }
#ifndef DEBUG
       if (fork())
               exit(0);
       for (f = 0; f < 10; f++)
               (void) close(f);
       (void) open("/", 0);
       (void) dup2(0, 1);
       (void) dup2(0, 2);
       { int t = open("/dev/tty", 2);
         if (t >= 0) {
               ioctl(t, TIOCNOTTY, (char *)0);
               (void) close(t);
         }
       }
#endif
       sin.sin_port = sp->s_port;
       argc--, argv++;
       if (argc > 0 && !strcmp(argv[0], "-d")) {
               options |= SO_DEBUG;
               argc--, argv++;
       }
       if (argc > 0) {
               int port = atoi(argv[0]);

               if (port < 0) {
                       fprintf(stderr, "%s: bad port #\n", argv[0]);
                       exit(1);
               }
               sin.sin_port = htons((u_short)port);
               argc--, argv++;
       }
       f = socket(AF_INET, SOCK_STREAM, 0, 0);
       if (f < 0) {
               perror("rshd: socket");
               exit(1);
       }
       if (options & SO_DEBUG && setsockopt(f, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
               perror("rshd: setsockopt (SO_DEBUG)");
       if (setsockopt(f, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
               perror("rshd: setsockopt (SO_KEEPALIVE)");
       linger = 60;                    /* XXX */
       if (setsockopt(f, SOL_SOCKET, SO_LINGER, &linger, 0) < 0)
               perror("rshd: setsockopt (SO_LINGER)");
       if (bind(f, (caddr_t)&sin, sizeof (sin), 0) < 0) {
               perror("rshd: bind");
               exit(1);
       }
       signal(SIGCHLD, reapchild);
       listen(f, 10);
       for (;;) {
               int g, len = sizeof (from);

               g = accept(f, &from, &len, 0);
               if (g < 0) {
                       if (errno == EINTR)
                               continue;
                       perror("rshd: accept");
                       continue;
               }
               if (fork() == 0) {
                       signal(SIGCHLD, SIG_IGN);
                       close(f);
                       doit(g, &from);
               }
               close(g);
       }
}

reapchild()
{
       union wait status;

       while (wait3(&status, WNOHANG, 0) > 0)
               ;
}

char    username[20] = "USER=";
char    homedir[64] = "HOME=";
char    shell[64] = "SHELL=";
char    *envinit[] =
           {homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0};
char    **environ;

doit(f, fromp)
       int f;
       struct sockaddr_in *fromp;
{
       char cmdbuf[NCARGS+1], *cp;
       char locuser[16], remuser[16];
       struct passwd *pwd;
       int s, backoff;
       struct hostent *hp;
       short port;
       int pv[2], pid, ready, readfrom, cc;
       char buf[BUFSIZ], sig;
       int one = 1;

       (void) signal(SIGINT, SIG_DFL);
       (void) signal(SIGQUIT, SIG_DFL);
       (void) signal(SIGTERM, SIG_DFL);
#ifdef DEBUG
       { int t = open("/dev/tty", 2);
         if (t >= 0) {
               ioctl(t, TIOCNOTTY, (char *)0);
               (void) close(t);
         }
       }
#endif
       fromp->sin_port = ntohs((u_short)fromp->sin_port);
       if (fromp->sin_family != AF_INET ||
           fromp->sin_port >= IPPORT_RESERVED) {
               fprintf(stderr, "rshd: malformed from address\n");
               exit(1);
       }
       (void) alarm(60);
       port = 0;
       for (;;) {
               char c;
               if (read(f, &c, 1) != 1) {
                       perror("rshd: read");
                       shutdown(f, 1+1);
                       exit(1);
               }
               if (c == 0)
                       break;
               port = port * 10 + c - '0';
       }
       (void) alarm(0);
       if (port != 0) {
               int lport = IPPORT_RESERVED - 1, retryshift;
               s = rresvport(&lport);
               if (s < 0) {
                       perror("rshd: can't get stderr port");
                       exit(1);
               }
               if (port >= IPPORT_RESERVED) {
                       fprintf(stderr, "rshd: 2nd port not reserved\n");
                       exit(1);
               }
               fromp->sin_port = htons((u_short)port);
               if (connect(s, fromp, sizeof (*fromp), 0) < 0) {
                       perror("rshd: connect");
                       exit(1);
               }
       }
       dup2(f, 0);
       dup2(f, 1);
       dup2(f, 2);
       hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
               fromp->sin_family);
       if (hp == 0) {
               error("Host name for your address unknown\n");
               exit(1);
       }
       getstr(remuser, sizeof(remuser), "remuser");
       getstr(locuser, sizeof(locuser), "locuser");
       getstr(cmdbuf, sizeof(cmdbuf), "command");
       setpwent();
       pwd = getpwnam(locuser);
       if (pwd == NULL) {
               error("Login incorrect.\n");
               exit(1);
       }
       endpwent();
       if (chdir(pwd->pw_dir) < 0) {
               error("No remote directory.\n");
               exit(1);
       }
       if (ruserok(hp->h_name, pwd->pw_uid == 0, remuser, locuser) < 0) {
               error("Permission denied.\n");
               exit(1);
       }
       (void) write(2, "\0", 1);
       if (port) {
               if (pipe(pv) < 0) {
                       error("Can't make pipe.\n");
                       exit(1);
               }
               pid = fork();
               if (pid == -1)  {
                       error("Try again.\n");
                       exit(1);
               }
               if (pid) {
                       (void) close(0); (void) close(1); (void) close(2);
                       (void) close(f); (void) close(pv[1]);
                       readfrom = (1<<s) | (1<<pv[0]);
                       ioctl(pv[1], FIONBIO, (char *)&one);
                       /* should set s nbio! */
                       do {
                               ready = readfrom;
                               if (select(16, &ready, 0, 0, 0) < 0)
                                       break;
                               if (ready & (1<<s)) {
                                       if (read(s, &sig, 1) <= 0)
                                               readfrom &= ~(1<<s);
                                       else
                                               killpg(pid, sig);
                               }
                               if (ready & (1<<pv[0])) {
                                       errno = 0;
                                       cc = read(pv[0], buf, sizeof (buf));
                                       if (cc <= 0) {
                                               shutdown(s, 1+1);
                                               readfrom &= ~(1<<pv[0]);
                                       } else
                                               (void) write(s, buf, cc);
                               }
                       } while (readfrom);
                       exit(0);
               }
               setpgrp(0, getpid());
               (void) close(s); (void) close(pv[0]);
               dup2(pv[1], 2);
       }
       if (*pwd->pw_shell == '\0')
               pwd->pw_shell = "/bin/sh";
       (void) close(f);
       initgroups(pwd->pw_name, pwd->pw_gid);
       (void) setgid(pwd->pw_gid);
       (void) setuid(pwd->pw_uid);
       environ = envinit;
       strncat(homedir, pwd->pw_dir, sizeof(homedir)-6);
       strncat(shell, pwd->pw_shell, sizeof(shell)-7);
       strncat(username, pwd->pw_name, sizeof(username)-6);
       cp = rindex(pwd->pw_shell, '/');
       if (cp)
               cp++;
       else
               cp = pwd->pw_shell;
       execl(pwd->pw_shell, cp, "-c", cmdbuf, 0);
       perror(pwd->pw_shell);
       exit(1);
protofail:
       error("rsh: protocol failure detected by remote\n");
       exit(1);
}

/* VARARGS 1 */
error(fmt)
       char *fmt;
{
       char buf[BUFSIZ];

       buf[0] = 1;
       (void) sprintf(buf+1, fmt);
       (void) write(2, buf, strlen(buf));
}

getstr(buf, cnt, err)
       char *buf;
       int cnt;
       char *err;
{
       char c;

       do {
               if (read(0, &c, 1) != 1)
                       exit(1);
               *buf++ = c;
               if (--cnt == 0) {
                       error("%s too long\n", err);
                       exit(1);
               }
       } while (c != 0);
}