minix/lib/ip/rcmd.c
2009-11-09 10:26:00 +00:00

284 lines
6.1 KiB
C

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. Neither the name of the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)rcmd.c 5.22 (Berkeley) 6/1/90";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <net/gen/netdb.h>
#include <net/gen/in.h>
#include <net/gen/tcp.h>
#include <net/gen/tcp_io.h>
#include <net/hton.h>
#include <net/netlib.h>
#define MAXHOSTNAMELEN 256
#define MAXPATHLEN PATH_MAX
#ifdef __STDC__
#define CONST const
#else
#define CONST
#endif
extern errno;
int rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
char **ahost;
int rport;
CONST char *locuser, *remuser, *cmd;
int *fd2p;
{
int fd, fd2, result;
struct hostent *hp;
int n;
static tcpport_t lport;
nwio_tcpconf_t tcpconf;
nwio_tcpcl_t tcpconnopt;
pid_t pid;
char num[8];
char c;
char *tcp_device;
fd= -1;
fd2= -1;
if (lport == 0) {
pid = getpid();
lport = 1;
do {
lport = (lport << 1) | (pid & 1);
pid >>= 1;
} while (lport < TCPPORT_RESERVED/2);
}
tcp_device= getenv("TCP_DEVICE");
if (tcp_device == NULL)
tcp_device= TCP_DEVICE;
hp= gethostbyname(*ahost);
if (!hp)
{
fprintf(stderr, "%s: unknown host\n", *ahost);
return -1;
}
*ahost= hp->h_name;
n = TCPPORT_RESERVED/2;
do
{
if (--lport < TCPPORT_RESERVED/2)
lport = TCPPORT_RESERVED-1;
fd= open (tcp_device, O_RDWR);
if (fd<0)
{
fprintf(stderr, "unable to open %s: %s\n",
tcp_device, strerror(errno));
goto bad;
}
tcpconf.nwtc_flags= NWTC_LP_SET | NWTC_SET_RA | NWTC_SET_RP |
NWTC_EXCL;
tcpconf.nwtc_locport= htons(lport);
tcpconf.nwtc_remport= rport;
tcpconf.nwtc_remaddr= *(ipaddr_t *)hp->h_addr;
result= ioctl(fd, NWIOSTCPCONF, &tcpconf);
if (result<0)
{
if (errno == EADDRINUSE)
{
close(fd);
continue;
}
fprintf(stderr, "unable to ioctl(NWIOSTCPCONF): %s\n",
strerror(errno));
goto bad;
}
tcpconf.nwtc_flags= NWTC_SHARED;
result= ioctl(fd, NWIOSTCPCONF, &tcpconf);
if (result<0)
{
fprintf(stderr, "unable to ioctl(NWIOSTCPCONF): %s\n",
strerror(errno));
goto bad;
}
tcpconnopt.nwtcl_flags= 0;
do
{
result= ioctl (fd, NWIOTCPCONN, &tcpconnopt);
if (result<0 && errno == EAGAIN)
{
sleep(2);
}
} while (result<0 && errno == EAGAIN);
if (result<0 && errno != EADDRINUSE)
{
fprintf(stderr,
"unable to ioctl(NWIOTCPCONN): %s\n",
strerror(errno));
goto bad;
}
if (result>=0)
break;
} while (--n > 0);
if (n == 0)
{
fprintf(stderr, "can't get port\n");
return -1;
}
if (!fd2p)
{
if (write(fd, "", 1) != 1)
{
fprintf(stderr, "unable to write: %s", strerror(errno));
goto bad;
}
}
else
{
fd2= open (tcp_device, O_RDWR);
if (fd2<0)
{
fprintf(stderr, "unable to open %s: %s\n",
tcp_device, strerror(errno));
goto bad;
}
tcpconf.nwtc_flags= NWTC_LP_SET | NWTC_UNSET_RA |
NWTC_UNSET_RP | NWTC_SHARED;
tcpconf.nwtc_locport= htons(lport);
result= ioctl(fd2, NWIOSTCPCONF, &tcpconf);
if (result<0)
{
fprintf(stderr,
"unable to ioctl(NWIOSTCPCONF): %s\n",
strerror(errno));
goto bad;
}
pid= fork();
if (pid<0)
{
fprintf(stderr, "unable to fork: %s\n",
strerror(errno));
goto bad;
}
if (!pid)
{
alarm(0);
signal(SIGALRM, SIG_DFL);
alarm(30); /* give up after half a minute */
tcpconnopt.nwtcl_flags= 0;
do
{
result= ioctl (fd2, NWIOTCPLISTEN,
&tcpconnopt);
if (result<0 && errno == EAGAIN)
{
sleep(2);
}
} while (result<0 && errno == EAGAIN);
if (result<0 && errno != EADDRINUSE)
{
fprintf(stderr,
"unable to ioctl(NWIOTCPLISTEN): %s\n",
strerror(errno));
exit(1);
}
if (result>=0)
exit(0);
else
exit(1);
}
/*
* This sleep is a HACK. The command that we are starting
* will try to connect to the fd2 port. It seems that for
* this to succeed the child process must have already made
* the call to ioctl above (the NWIOTCPLISTEN) call.
* The sleep gives the child a chance to make the call
* before the parent sends the port number to the
* command being started.
*/
sleep(1);
sprintf(num, "%d", lport);
if (write(fd, num, strlen(num)+1) != strlen(num)+1)
{
fprintf(stderr, "unable to write: %s\n",
strerror(errno));
goto bad;
}
}
write (fd, locuser, strlen(locuser)+1);
write (fd, remuser, strlen(remuser)+1);
write (fd, cmd, strlen(cmd)+1);
if (read(fd, &c, 1) != 1)
{
fprintf(stderr, "unable to read: %s\n", strerror(errno) );
goto bad;
}
if (c != 0)
{
while (read(fd, &c, 1) == 1)
{
write(2, &c, 1);
if (c == '\n')
break;
}
goto bad;
}
if (fd2p)
{
*fd2p= fd2;
result= ioctl(fd2, NWIOGTCPCONF, &tcpconf);
if (result<0)
{
fprintf(stderr, "unable to ioctl(NWIOGTCPCONF): %s\n",
strerror(errno) );
goto bad;
}
if (ntohs(tcpconf.nwtc_remport) >= TCPPORT_RESERVED)
{
fprintf(stderr, "unable to setup 2nd channel\n");
goto bad;
}
}
return fd;
bad:
if (fd>=0)
close(fd);
if (fd2>=0)
close(fd2);
return -1;
}