diff options
Diffstat (limited to 'gnu/libexec/uucp/libunix/tcp.c')
-rw-r--r-- | gnu/libexec/uucp/libunix/tcp.c | 444 |
1 files changed, 444 insertions, 0 deletions
diff --git a/gnu/libexec/uucp/libunix/tcp.c b/gnu/libexec/uucp/libunix/tcp.c new file mode 100644 index 0000000..6ec39f2 --- /dev/null +++ b/gnu/libexec/uucp/libunix/tcp.c @@ -0,0 +1,444 @@ +/* tcp.c + Code to handle TCP connections. + + Copyright (C) 1991, 1992, 1993, 1995 Ian Lance Taylor + + This file is part of the Taylor UUCP package. + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + 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. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + + The author of the program may be contacted at ian@airs.com or + c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144. + */ + +#include "uucp.h" + +#if USE_RCS_ID +const char tcp_rcsid[] = "$Id: tcp.c,v 1.5 1995/06/21 19:20:46 ian Rel $"; +#endif + +#if HAVE_TCP + +#include "uudefs.h" +#include "uuconf.h" +#include "sysdep.h" +#include "conn.h" +#include "system.h" + +#include <errno.h> + +#if HAVE_SYS_TYPES_TCP_H +#include <sys/types.tcp.h> +#endif +#include <sys/socket.h> +#include <netdb.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#if HAVE_FCNTL_H +#include <fcntl.h> +#else +#if HAVE_SYS_FILE_H +#include <sys/file.h> +#endif +#endif + +#ifndef FD_CLOEXEC +#define FD_CLOEXEC 1 +#endif + +/* This code handles TCP connections. It assumes a Berkeley socket + interface. */ + +/* The normal "uucp" port number. */ +#define IUUCP_PORT (540) + +/* Local functions. */ +static void utcp_free P((struct sconnection *qconn)); +static boolean ftcp_open P((struct sconnection *qconn, long ibaud, + boolean fwait)); +static boolean ftcp_close P((struct sconnection *qconn, + pointer puuconf, + struct uuconf_dialer *qdialer, + boolean fsuccess)); +static boolean ftcp_dial P((struct sconnection *qconn, pointer puuconf, + const struct uuconf_system *qsys, + const char *zphone, + struct uuconf_dialer *qdialer, + enum tdialerfound *ptdialer)); +static int itcp_port_number P((const char *zport)); + +/* The command table for a TCP connection. */ +static const struct sconncmds stcpcmds = +{ + utcp_free, + NULL, /* pflock */ + NULL, /* pfunlock */ + ftcp_open, + ftcp_close, + ftcp_dial, + fsysdep_conn_read, + fsysdep_conn_write, + fsysdep_conn_io, + NULL, /* pfbreak */ + NULL, /* pfset */ + NULL, /* pfcarrier */ + fsysdep_conn_chat, + NULL /* pibaud */ +}; + +/* Initialize a TCP connection. */ + +boolean +fsysdep_tcp_init (qconn) + struct sconnection *qconn; +{ + struct ssysdep_conn *q; + + q = (struct ssysdep_conn *) xmalloc (sizeof (struct ssysdep_conn)); + q->o = -1; + q->ord = -1; + q->owr = -1; + q->zdevice = NULL; + q->iflags = -1; + q->iwr_flags = -1; + q->fterminal = FALSE; + q->ftli = FALSE; + q->ibaud = 0; + + qconn->psysdep = (pointer) q; + qconn->qcmds = &stcpcmds; + return TRUE; +} + +/* Free a TCP connection. */ + +static void +utcp_free (qconn) + struct sconnection *qconn; +{ + xfree (qconn->psysdep); +} + +/* Open a TCP connection. If the fwait argument is TRUE, we are + running as a server. Otherwise we are just trying to reach another + system. */ + +static boolean +ftcp_open (qconn, ibaud, fwait) + struct sconnection *qconn; + long ibaud; + boolean fwait; +{ + struct ssysdep_conn *qsysdep; + struct sockaddr_in s; + const char *zport; + uid_t ieuid; + boolean fswap; + + ulog_device ("TCP"); + + qsysdep = (struct ssysdep_conn *) qconn->psysdep; + + qsysdep->o = socket (AF_INET, SOCK_STREAM, 0); + if (qsysdep->o < 0) + { + ulog (LOG_ERROR, "socket: %s", strerror (errno)); + return FALSE; + } + + if (fcntl (qsysdep->o, F_SETFD, + fcntl (qsysdep->o, F_GETFD, 0) | FD_CLOEXEC) < 0) + { + ulog (LOG_ERROR, "fcntl (FD_CLOEXEC): %s", strerror (errno)); + (void) close (qsysdep->o); + qsysdep->o = -1; + return FALSE; + } + + qsysdep->iflags = fcntl (qsysdep->o, F_GETFL, 0); + if (qsysdep->iflags < 0) + { + ulog (LOG_ERROR, "fcntl: %s", strerror (errno)); + (void) close (qsysdep->o); + qsysdep->o = -1; + return FALSE; + } + + /* We save our process ID in the qconn structure. This is checked + in ftcp_close. */ + qsysdep->ipid = getpid (); + + /* If we aren't waiting for a connection, we're done. */ + if (! fwait) + return TRUE; + + /* Run as a server and wait for a new connection. The code in + uucico.c has already detached us from our controlling terminal. + From this point on if the server gets an error we exit; we only + return if we have received a connection. It would be more robust + to respawn the server if it fails; someday. */ + bzero ((pointer) &s, sizeof s); + s.sin_family = AF_INET; + zport = qconn->qport->uuconf_u.uuconf_stcp.uuconf_zport; + s.sin_port = itcp_port_number (zport); + s.sin_addr.s_addr = htonl (INADDR_ANY); + + /* Swap to our real user ID when doing the bind call. This will + permit the server to use privileged TCP ports when invoked by + root. We only swap if our effective user ID is not root, so that + the program can also be made suid root in order to get privileged + ports when invoked by anybody. */ + fswap = geteuid () != 0; + if (fswap) + { + if (! fsuser_perms (&ieuid)) + { + (void) close (qsysdep->o); + qsysdep->o = -1; + return FALSE; + } + } + + if (bind (qsysdep->o, (struct sockaddr *) &s, sizeof s) < 0) + { + if (fswap) + (void) fsuucp_perms ((long) ieuid); + ulog (LOG_FATAL, "bind: %s", strerror (errno)); + } + + /* Now swap back to the uucp user ID. */ + if (fswap) + { + if (! fsuucp_perms ((long) ieuid)) + ulog (LOG_FATAL, "Could not swap back to UUCP user permissions"); + } + + if (listen (qsysdep->o, 5) < 0) + ulog (LOG_FATAL, "listen: %s", strerror (errno)); + + while (! FGOT_SIGNAL ()) + { + size_t clen; + int onew; + pid_t ipid; + + DEBUG_MESSAGE0 (DEBUG_PORT, + "ftcp_open: Waiting for connections"); + + clen = sizeof s; + onew = accept (qsysdep->o, (struct sockaddr *) &s, &clen); + if (onew < 0) + ulog (LOG_FATAL, "accept: %s", strerror (errno)); + + DEBUG_MESSAGE0 (DEBUG_PORT, + "ftcp_open: Got connection; forking"); + + ipid = ixsfork (); + if (ipid < 0) + ulog (LOG_FATAL, "fork: %s", strerror (errno)); + if (ipid == 0) + { + (void) close (qsysdep->o); + qsysdep->o = onew; + + /* Now we fork and let our parent die, so that we become + a child of init. This lets the main server code wait + for its child and then continue without accumulating + zombie children. */ + ipid = ixsfork (); + if (ipid < 0) + { + ulog (LOG_ERROR, "fork: %s", strerror (errno)); + _exit (EXIT_FAILURE); + } + + if (ipid != 0) + _exit (EXIT_SUCCESS); + + ulog_id (getpid ()); + + return TRUE; + } + + (void) close (onew); + + /* Now wait for the child. */ + (void) ixswait ((unsigned long) ipid, (const char *) NULL); + } + + /* We got a signal. */ + usysdep_exit (FALSE); + + /* Avoid compiler warnings. */ + return FALSE; +} + +/* Close the port. */ + +/*ARGSUSED*/ +static boolean +ftcp_close (qconn, puuconf, qdialer, fsuccess) + struct sconnection *qconn; + pointer puuconf; + struct uuconf_dialer *qdialer; + boolean fsuccess; +{ + struct ssysdep_conn *qsysdep; + boolean fret; + + qsysdep = (struct ssysdep_conn *) qconn->psysdep; + fret = TRUE; + if (qsysdep->o >= 0 && close (qsysdep->o) < 0) + { + ulog (LOG_ERROR, "close: %s", strerror (errno)); + fret = FALSE; + } + qsysdep->o = -1; + + /* If the current pid is not the one we used to open the port, then + we must have forked up above and we are now the child. In this + case, we are being called from within the fendless loop in + uucico.c. We return FALSE to force the loop to end and the child + to exit. This should be handled in a cleaner fashion. */ + if (qsysdep->ipid != getpid ()) + fret = FALSE; + + return fret; +} + +/* Dial out on a TCP port, so to speak: connect to a remote computer. */ + +/*ARGSUSED*/ +static boolean +ftcp_dial (qconn, puuconf, qsys, zphone, qdialer, ptdialer) + struct sconnection *qconn; + pointer puuconf; + const struct uuconf_system *qsys; + const char *zphone; + struct uuconf_dialer *qdialer; + enum tdialerfound *ptdialer; +{ + struct ssysdep_conn *qsysdep; + const char *zhost; + struct hostent *q; + struct sockaddr_in s; + const char *zport; + char **pzdialer; + + qsysdep = (struct ssysdep_conn *) qconn->psysdep; + + *ptdialer = DIALERFOUND_FALSE; + + zhost = zphone; + if (zhost == NULL) + { + if (qsys == NULL) + { + ulog (LOG_ERROR, "No address for TCP connection"); + return FALSE; + } + zhost = qsys->uuconf_zname; + } + + errno = 0; + q = gethostbyname ((char *) zhost); + if (q != NULL) + { + s.sin_family = q->h_addrtype; + memcpy (&s.sin_addr.s_addr, q->h_addr, (size_t) q->h_length); + } + else + { + if (errno != 0) + { + ulog (LOG_ERROR, "gethostbyname (%s): %s", zhost, strerror (errno)); + return FALSE; + } + + s.sin_family = AF_INET; + s.sin_addr.s_addr = inet_addr ((char *) zhost); + if ((long) s.sin_addr.s_addr == (long) -1) + { + ulog (LOG_ERROR, "%s: unknown host name", zhost); + return FALSE; + } + } + + zport = qconn->qport->uuconf_u.uuconf_stcp.uuconf_zport; + s.sin_port = itcp_port_number (zport); + + if (connect (qsysdep->o, (struct sockaddr *) &s, sizeof s) < 0) + { + ulog (LOG_ERROR, "connect: %s", strerror (errno)); + return FALSE; + } + + /* Handle the dialer sequence, if any. */ + pzdialer = qconn->qport->uuconf_u.uuconf_stcp.uuconf_pzdialer; + if (pzdialer != NULL && *pzdialer != NULL) + { + if (! fconn_dial_sequence (qconn, puuconf, pzdialer, qsys, zphone, + qdialer, ptdialer)) + return FALSE; + } + + return TRUE; +} + +/* Get the port number given a name. The argument will almost always + be "uucp" so we cache that value. The return value is always in + network byte order. This returns -1 on error. */ + +static int +itcp_port_number (zname) + const char *zname; +{ + boolean fuucp; + static int iuucp; + int i; + char *zend; + struct servent *q; + + fuucp = strcmp (zname, "uucp") == 0; + if (fuucp && iuucp != 0) + return iuucp; + + /* Try it as a number first. */ + i = strtol ((char *) zname, &zend, 10); + if (i != 0 && *zend == '\0') + return htons (i); + + q = getservbyname ((char *) zname, (char *) "tcp"); + if (q == NULL) + { + /* We know that the "uucp" service should be 540, even if isn't + in /etc/services. */ + if (fuucp) + { + iuucp = htons (IUUCP_PORT); + return iuucp; + } + ulog (LOG_ERROR, "getservbyname (%s): %s", zname, strerror (errno)); + return -1; + } + + if (fuucp) + iuucp = q->s_port; + + return q->s_port; +} + +#endif /* HAVE_TCP */ |