Initial revision

tftpd/Makefile

@@ -0,0 +1,27 @@
+all: tftpd
+
+include ../MCONFIG
+include ../MRULES
+
+OBJS = tftpd.o tftpsubs.o
+
+tftpd: $(OBJS)
+	$(CC) $(LDFLAGS) $^ $(LIBS) -o $@
+
+tftpsubs.c: 
+	ln -sf ../tftp/tftpsubs.c .
+tftpsubs.h: 
+	ln -sf ../tftp/tftpsubs.h .
+
+$(OBJS): tftpsubs.h
+
+install: tftpd
+	$(INSTALL_PROGRAM) tftpd $(INSTALLROOT)$(SBINDIR)/in.tftpd
+	$(INSTALL_DATA)    tftpd.8 $(INSTALLROOT)$(MANDIR)/man8/in.tftpd.8
+	ln -sf in.tftpd.8 $(INSTALLROOT)$(MANDIR)/man8/tftpd.8
+
+clean:
+	rm -f *.o tftpd tftpsubs.c tftpsubs.h
+
+spotless: clean
+	rm -f *~

tftpd/tftpd.8

@@ -0,0 +1,141 @@
+.\"   $OpenBSD: tftpd.8,v 1.7 1999/07/09 13:35:51 aaron Exp $
+.\"
+.\" Copyright (c) 1983, 1991 The Regents of the University of California.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"	This product includes software developed by the University of
+.\"	California, Berkeley and its contributors.
+.\" 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"	from: @(#)tftpd.8	6.7 (Berkeley) 5/13/91
+.\"	$OpenBSD: tftpd.8,v 1.7 1999/07/09 13:35:51 aaron Exp $
+.\"
+.Dd June 11, 1997
+.Dt TFTPD 8
+.Os
+.Sh NAME
+.Nm tftpd
+.Nd
+.Tn DARPA
+Trivial File Transfer Protocol server
+.Sh SYNOPSIS
+.Nm tftpd
+.Op Fl cs
+.Op Fl r Ar option...
+.Op Ar directory
+.Sh DESCRIPTION
+.Nm
+is a server which supports the
+.Tn DARPA
+Trivial File Transfer
+Protocol.
+The
+.Tn TFTP
+server operates
+at the port indicated in the
+.Ql tftp
+service description;
+see
+.Xr services 5 .
+The server is normally started by
+.Xr inetd 8 .
+.Pp
+The use of
+.Xr tftp 1
+does not require an account or password on the remote system.
+Due to the lack of authentication information,
+.Nm
+will allow only publicly readable files to be
+accessed.
+Files may be written only if they already exist and are publicly writable.
+Note that this extends the concept of
+.Dq public
+to include
+all users on all hosts that can be reached through the network;
+this may not be appropriate on all systems, and its implications
+should be considered before enabling tftp service.
+The server should have the user ID with the lowest possible privilege.
+.Pp
+Access to files may be restricted by invoking
+.Nm
+with a list of directories by including pathnames
+as server program arguments in
+.Pa /etc/inetd.conf .
+In this case access is restricted to files whose
+names are prefixed by the one of the given directories.
+.Pp
+If the
+.Fl c
+flag is used,
+.Nm
+will allow new files to be created; otherwise uploaded files must already
+exist.  Files are created with default permissions allowing anyone to read
+or write to them.
+.Pp
+When using the
+.Fl s
+flag with a directory name,
+.Nm
+will
+.Xr chroot 2
+on startup; therefore the remote host is not expected to pass the directory
+as part of the file name to transfer.  This option is intended primarily for
+compatibility with SunOS boot ROMs which do not include a directory name.
+.Pp
+This version of
+.Nm
+supports RFC 2347 option negotiation; the current version supports the
+.Pa blksize
+(RFC 2348),
+.Pa blksize ,
+(RFC 2349), and
+.Pa timeout
+(RFC 2349) options.  The
+.Fl r
+flag can be used to disable options individually; this may allow
+working around client bugs.
+.Sh SEE ALSO
+.Xr tftp 1 ,
+.Xr inetd 8
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.Bx 4.2 .
+.Pp
+The
+.Fl s
+flag appeared in NetBSD 0.9a.
+.Pp
+The
+.Fl c
+flag was added in OpenBSD 2.1 .
+.Pp
+The
+.Fl r
+flag and RFC 2347 options were added by H. Peter Anvin based on
+patches by Markus Gutschke and Gero Kulhman.

tftpd/tftpd.c

@@ -0,0 +1,821 @@
+/*	$OpenBSD: tftpd.c,v 1.13 1999/06/23 17:01:36 deraadt Exp $	*/
+
+/*
+ * Copyright (c) 1983 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static const char *copyright =
+"@(#) Copyright (c) 1983 Regents of the University of California.\n\
+ All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+/*static char sccsid[] = "from: @(#)tftpd.c	5.13 (Berkeley) 2/26/91";*/
+/*static char rcsid[] = "$OpenBSD: tftpd.c,v 1.13 1999/06/23 17:01:36 deraadt Exp $: tftpd.c,v 1.6 1997/02/16 23:49:21 deraadt Exp $";*/
+static const char *cvsid = "tftp-hpa $Id$";
+#endif /* not lint */
+
+/*
+ * Trivial file transfer protocol server.
+ *
+ * This version includes many modifications by Jim Guyton <guyton@rand-unix>
+ */
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <fcntl.h>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/tftp.h>
+#include <netdb.h>
+
+#include <setjmp.h>
+#include <syslog.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+#include <pwd.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "tftpsubs.h"
+
+#define	TIMEOUT 5		/* Default timeout (seconds) */
+#define TRIES   4		/* Number of attempts to send each packet */
+#define TIMEOUT_LIMIT (TRIES*(TRIES+1)/2)
+
+#ifndef OACK
+#define OACK	6
+#endif
+#ifndef EOPTNEG
+#define EOPTNEG	8
+#endif
+
+extern	int errno;
+extern	char *__progname;
+struct	sockaddr_in s_in = { AF_INET };
+int	peer;
+int	timeout    = TIMEOUT;
+int	rexmtval   = TIMEOUT;
+int	maxtimeout = TIMEOUT_LIMIT*TIMEOUT;
+
+#define	PKTSIZE	MAX_SEGSIZE+4
+char	buf[PKTSIZE];
+char	ackbuf[PKTSIZE];
+struct	sockaddr_in from;
+int	fromlen;
+off_t	tsize;
+int     tsize_ok;
+
+int	ndirs;
+char	**dirs;
+
+int	secure = 0;
+int	cancreate = 0;
+
+struct formats;
+
+int tftp(struct tftphdr *, int);
+void nak(int);
+void timer(int);
+void justquit(int);
+void do_opt(char *, char *, char **);
+
+int     set_blksize(char *, char **);
+int     set_tsize(char *, char **);
+int	set_timeout(char *, char **);
+
+struct options {
+        char    *o_opt;
+        int     (*o_fnc)(char *, char **);
+} options[] = {
+        { "blksize",    set_blksize  },
+        { "tsize",      set_tsize },
+	{ "timeout",	set_timeout  },
+        { NULL,         NULL }
+};
+
+
+
+static void
+usage(void)
+{
+	syslog(LOG_ERR, "Usage: %s [-cs] [-r option...] [directory ...]",
+	       __progname);
+	exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+	struct tftphdr *tp;
+	struct passwd *pw;
+	struct options *opt;
+	int n = 0;
+	int on = 1;
+	int fd = 0;
+	int pid;
+	int i, j;
+	int c;
+
+	openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_DAEMON);
+
+	while ((c = getopt(argc, argv, "csr:")) != -1)
+		switch (c) {
+		case 'c':
+			cancreate = 1;
+			break;
+		case 's':
+			secure = 1;
+			break;
+		case 'r':
+		  for ( opt = options ; opt->o_opt ; opt++ ) {
+		    if ( !strcasecmp(optarg, opt->o_opt) ) {
+		      opt->o_opt = ""; /* Don't support this option */
+		      break;
+		    }
+		  }
+		  if ( !opt->o_opt ) {
+		        syslog(LOG_ERR, "Unknown option: %s", optarg);
+			exit(1);
+		  }
+		  break;
+
+		default:
+			usage();
+			break;
+		}
+
+	for (; optind != argc; optind++) {
+		if (dirs)
+			dirs = realloc(dirs, (ndirs+2) * sizeof (char *));
+		else
+			dirs = calloc(ndirs+2, sizeof(char *));
+		if (dirs == NULL) {
+			syslog(LOG_ERR, "malloc: %m");
+			exit(1);
+		}			
+		dirs[n++] = argv[optind];
+		dirs[n] = NULL;
+		ndirs++;
+	}
+
+	if (secure) {
+		if (ndirs == 0) {
+			syslog(LOG_ERR, "no -s directory");
+			exit(1);
+		}
+		if (ndirs > 1) {
+			syslog(LOG_ERR, "too many -s directories");
+			exit(1);
+		}
+		if (chdir(dirs[0])) {
+			syslog(LOG_ERR, "%s: %m", dirs[0]);
+			exit(1);
+		}
+	}
+
+	pw = getpwnam("nobody");
+	if (!pw) {
+		syslog(LOG_ERR, "no nobody: %m");
+		exit(1);
+	}
+
+	if (secure && chroot(".")) {
+		syslog(LOG_ERR, "chroot: %m");
+		exit(1);
+	}
+
+	(void) setegid(pw->pw_gid);
+	(void) setgid(pw->pw_gid);
+	(void) seteuid(pw->pw_uid);
+	(void) setuid(pw->pw_uid);
+
+	if (ioctl(fd, FIONBIO, &on) < 0) {
+		syslog(LOG_ERR, "ioctl(FIONBIO): %m");
+		exit(1);
+	}
+	fromlen = sizeof (from);
+	n = recvfrom(fd, buf, sizeof (buf), 0,
+	    (struct sockaddr *)&from, &fromlen);
+	if (n < 0) {
+		syslog(LOG_ERR, "recvfrom: %m");
+		exit(1);
+	}
+	/*
+	 * Now that we have read the message out of the UDP
+	 * socket, we fork and exit.  Thus, inetd will go back
+	 * to listening to the tftp port, and the next request
+	 * to come in will start up a new instance of tftpd.
+	 *
+	 * We do this so that inetd can run tftpd in "wait" mode.
+	 * The problem with tftpd running in "nowait" mode is that
+	 * inetd may get one or more successful "selects" on the
+	 * tftp port before we do our receive, so more than one
+	 * instance of tftpd may be started up.  Worse, if tftpd
+	 * break before doing the above "recvfrom", inetd would
+	 * spawn endless instances, clogging the system.
+	 */
+	for (i = 1; i < 20; i++) {
+		pid = fork();
+		if (pid < 0) {
+			sleep(i);
+			/*
+			 * flush out to most recently sent request.
+			 *
+			 * This may drop some request, but those
+			 * will be resent by the clients when
+			 * they timeout.  The positive effect of
+			 * this flush is to (try to) prevent more
+			 * than one tftpd being started up to service
+			 * a single request from a single client.
+			 */
+			j = sizeof from;
+			i = recvfrom(fd, buf, sizeof (buf), 0,
+			    (struct sockaddr *)&from, &j);
+			if (i > 0) {
+				n = i;
+				fromlen = j;
+			}
+		} else
+			break;
+	}
+	if (pid < 0) {
+		syslog(LOG_ERR, "fork: %m");
+		exit(1);
+	} else if (pid != 0)
+		exit(0);
+
+	from.sin_family = AF_INET;
+	alarm(0);
+	close(fd);
+	close(1);
+	peer = socket(AF_INET, SOCK_DGRAM, 0);
+	if (peer < 0) {
+		syslog(LOG_ERR, "socket: %m");
+		exit(1);
+	}
+	if (bind(peer, (struct sockaddr *)&s_in, sizeof (s_in)) < 0) {
+		syslog(LOG_ERR, "bind: %m");
+		exit(1);
+	}
+	if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
+		syslog(LOG_ERR, "connect: %m");
+		exit(1);
+	}
+	tp = (struct tftphdr *)buf;
+	tp->th_opcode = ntohs(tp->th_opcode);
+	if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
+		tftp(tp, n);
+	exit(0);
+}
+
+int	validate_access(char *, int, struct formats *);
+void	sendfile(struct formats *, struct tftphdr *, int);
+void	recvfile(struct formats *, struct tftphdr *, int);
+
+struct formats {
+	char	*f_mode;
+	int	(*f_validate)(char *, int, struct formats *);
+	void	(*f_send)(struct formats *, struct tftphdr *, int);
+	void	(*f_recv)(struct formats *, struct tftphdr *, int);
+	int	f_convert;
+} formats[] = {
+	{ "netascii",	validate_access,	sendfile,	recvfile, 1 },
+	{ "octet",	validate_access,	sendfile,	recvfile, 0 },
+	{ NULL }
+};
+
+/*
+ * Handle initial connection protocol.
+ */
+int
+tftp(struct tftphdr *tp, int size)
+{
+	char *cp;
+	int argn, ecode;
+	struct formats *pf = NULL;
+	char *filename, *mode = NULL;
+
+        char *val = NULL, *opt = NULL;
+        char *ap = ackbuf + 2;
+
+        ((struct tftphdr *)ackbuf)->th_opcode = ntohs(OACK);
+
+	filename = cp = tp->th_stuff;
+	argn = 0;
+
+	while ( cp < buf + size && *cp ) {
+	     do {
+		  cp++;
+	     } while (cp < buf + size && *cp);
+
+	     if ( *cp ) {
+		  nak(EBADOP);	/* Corrupt packet - no final NULL */
+		  exit(0);
+	     }
+
+	     argn++;
+	     if (argn == 1) {
+		  mode = ++cp;
+	     } else if (argn == 2) {
+		  for (cp = mode; *cp; cp++)
+			    *cp = tolower(*cp);
+		  for (pf = formats; pf->f_mode; pf++) {
+		       if (!strcmp(pf->f_mode, mode))
+			    break;
+		  }
+		  if (!pf->f_mode) {
+		       nak(EBADOP);
+		       exit(0);
+		  }
+		  ecode = (*pf->f_validate)(filename, tp->th_opcode, pf);
+		  if (ecode) {
+		       nak(ecode);
+		       exit(0);
+		  }
+		  opt = ++cp;
+	     } else if ( argn & 1 ) {
+		  val = ++cp;
+	     } else {
+		  do_opt(opt, val, &ap);
+		  opt = ++cp;
+	     }
+	}
+
+	if (!pf) {
+	     nak(EBADOP);
+	     exit(0);
+	}
+
+	if ( ap != (ackbuf+2) ) {
+	     if ( tp->th_opcode == WRQ )
+		  (*pf->f_recv)(pf, ackbuf, ap-ackbuf);
+	     else
+		  (*pf->f_send)(pf, ackbuf, ap-ackbuf);
+	} else {
+	     if (tp->th_opcode == WRQ)
+		  (*pf->f_recv)(pf, NULL, 0);
+	     else
+		  (*pf->f_send)(pf, NULL, 0);
+	}
+	exit(1);
+}
+
+/*
+ * Set a non-standard block size (c.f. RFC2348)
+ */
+int
+set_blksize(char *val, char **ret)
+{
+  	static char b_ret[6];
+        int sz = atoi(val);
+
+        if (sz < 8)
+                return(0);
+        else if (sz > MAX_SEGSIZE)
+                sz = MAX_SEGSIZE;
+
+        segsize = sz;
+        sprintf(*ret = b_ret, "%d", sz);
+        return(1);
+}
+
+
+/*
+ * Return a file size (c.f. RFC2349)
+ * For netascii mode, we don't know the size ahead of time;
+ * so reject the option.
+ */
+int
+set_tsize(char *val, char **ret)
+{
+        static char b_ret[sizeof(off_t)*CHAR_BIT/3+2];
+        off_t sz = atol(val);
+
+	if ( !tsize_ok )
+	  return 0;
+
+        if (sz == 0)
+                sz = tsize;
+        sprintf(*ret = b_ret, "%lu", sz);
+        return(1);
+}
+
+/*
+ * Set the timeout (c.f. RFC2349)
+ */
+int
+set_timeout(char *val, char **ret)
+{
+	static char b_ret[4];
+	unsigned long to = atol(val);
+
+	if ( to < 1 || to > 255 )
+	  return 0;
+
+	timeout    = to;
+	rexmtval   = to;
+	maxtimeout = TIMEOUT_LIMIT*to;
+
+	sprintf(*ret = b_ret, "%lu", to);
+	return(1);
+}
+
+/*
+ * Parse RFC2347 style options
+ */
+void
+do_opt(char *opt, char *val, char **ap)
+{
+     struct options *po;
+     char *ret;
+     
+     if ( !*opt )
+	  return;
+
+     for (po = options; po->o_opt; po++)
+	  if (!strcasecmp(po->o_opt, opt)) {
+	       if (po->o_fnc(val, &ret)) {
+		    if (*ap + strlen(opt) + strlen(ret) + 2 >=
+			ackbuf + sizeof(ackbuf)) {
+			 nak(ENOSPACE);	/* EOPTNEG? */
+			 exit(0);
+		    }
+		    *ap = strrchr(strcpy(strrchr(strcpy(*ap, opt),'\0') + 1,
+					 ret),'\0') + 1;
+	       } else {
+		    nak(EOPTNEG);
+		    exit(0);
+	       }
+	       break;
+	  }
+     return;
+}
+
+
+FILE *file;
+
+/*
+ * Validate file access.  Since we
+ * have no uid or gid, for now require
+ * file to exist and be publicly
+ * readable/writable.
+ * If we were invoked with arguments
+ * from inetd then the file must also be
+ * in one of the given directory prefixes.
+ * Note also, full path name must be
+ * given as we have no login directory.
+ */
+int
+validate_access(char *filename, int mode, struct formats *pf)
+{
+	struct stat stbuf;
+	int	fd, wmode;
+	char *cp, **dirp;
+
+	tsize_ok = 0;
+
+	if (!secure) {
+		if (*filename != '/')
+			return (EACCESS);
+		/*
+		 * prevent tricksters from getting around the directory
+		 * restrictions
+		 */
+		for (cp = filename + 1; *cp; cp++)
+			if(*cp == '.' && strncmp(cp-1, "/../", 4) == 0)
+				return(EACCESS);
+		for (dirp = dirs; *dirp; dirp++)
+			if (strncmp(filename, *dirp, strlen(*dirp)) == 0)
+				break;
+		if (*dirp==0 && dirp!=dirs)
+			return (EACCESS);
+	}
+
+	/*
+	 * We use different a different permissions scheme if `cancreate' is
+	 * set.
+	 */
+	wmode = O_TRUNC;
+	if (stat(filename, &stbuf) < 0) {
+		if (!cancreate)
+			return (errno == ENOENT ? ENOTFOUND : EACCESS);
+		else {
+			if ((errno == ENOENT) && (mode != RRQ))
+				wmode |= O_CREAT;
+			else
+				return(EACCESS);
+		}
+	} else {
+		if (mode == RRQ) {
+			if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)
+				return (EACCESS);
+			tsize = stbuf.st_size;
+			tsize_ok = !pf->f_convert;
+		} else {
+			if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
+				return (EACCESS);
+			tsize = 0;
+			tsize_ok = 1;
+		}
+	}
+	fd = open(filename, mode == RRQ ? O_RDONLY : (O_WRONLY|wmode), 0666);
+	if (fd < 0)
+		return (errno + 100);
+	/*
+	 * If the file was created, set default permissions.
+	 */
+	if ((wmode & O_CREAT) && fchmod(fd, 0666) < 0) {
+		int serrno = errno;
+
+		close(fd);
+		unlink(filename);
+
+		return (serrno + 100);
+	}
+	file = fdopen(fd, (mode == RRQ)? "r":"w");
+	if (file == NULL)
+		return (errno + 100);
+	return (0);
+}
+
+int	timeout;
+jmp_buf	timeoutbuf;
+
+void
+timer(int sig)
+{
+
+	timeout += rexmtval;
+	if (timeout >= maxtimeout)
+		exit(0);
+	longjmp(timeoutbuf, 1);
+}
+
+/*
+ * Send the requested file.
+ */
+void
+sendfile(struct formats *pf, struct tftphdr *oap, int oacklen)
+{
+	struct tftphdr *dp;
+	struct tftphdr *ap;    /* ack packet */
+	int block = 1, size, n;
+
+	signal(SIGALRM, timer);
+	ap = (struct tftphdr *)ackbuf;
+
+        if (oap) {
+	     timeout = 0;
+	     (void)setjmp(timeoutbuf);
+oack:
+	     if (send(peer, oap, oacklen, 0) != oacklen) {
+		  syslog(LOG_ERR, "tftpd: oack: %m\n");
+		  goto abort;
+	     }
+	     for ( ; ; ) {
+		  alarm(rexmtval);
+		  n = recv(peer, ackbuf, sizeof(ackbuf), 0);
+		  alarm(0);
+		  if (n < 0) {
+		       syslog(LOG_ERR, "tftpd: read: %m\n");
+		       goto abort;
+		  }
+		  ap->th_opcode = ntohs((u_short)ap->th_opcode);
+		  ap->th_block = ntohs((u_short)ap->th_block);
+		  
+		  if (ap->th_opcode == ERROR) {
+		       syslog(LOG_ERR, "tftp: client does not accept "
+			      "options\n");
+		       goto abort;
+		  }
+		  if (ap->th_opcode == ACK) {
+		       if (ap->th_block == 0)
+			    break;
+		       /* Resynchronize with the other side */
+		       (void)synchnet(peer);
+		       goto oack;
+		  }
+	     }
+        }
+
+	dp = r_init();
+	do {
+		size = readit(file, &dp, pf->f_convert);
+		if (size < 0) {
+			nak(errno + 100);
+			goto abort;
+		}
+		dp->th_opcode = htons((u_short)DATA);
+		dp->th_block = htons((u_short)block);
+		timeout = 0;
+		(void) setjmp(timeoutbuf);
+
+send_data:
+		if (send(peer, dp, size + 4, 0) != size + 4) {
+			syslog(LOG_ERR, "tftpd: write: %m");
+			goto abort;
+		}
+		read_ahead(file, pf->f_convert);
+		for ( ; ; ) {
+			alarm(rexmtval);	/* read the ack */
+			n = recv(peer, ackbuf, sizeof (ackbuf), 0);
+			alarm(0);
+			if (n < 0) {
+				syslog(LOG_ERR, "tftpd: read(ack): %m");
+				goto abort;
+			}
+			ap->th_opcode = ntohs((u_short)ap->th_opcode);
+			ap->th_block = ntohs((u_short)ap->th_block);
+
+			if (ap->th_opcode == ERROR)
+				goto abort;
+			
+			if (ap->th_opcode == ACK) {
+				if (ap->th_block == block) {
+					break;
+				}
+				/* Re-synchronize with the other side */
+				(void) synchnet(peer);
+				if (ap->th_block == (block -1)) {
+					goto send_data;
+				}
+			}
+
+		}
+		block++;
+	} while (size == segsize);
+abort:
+	(void) fclose(file);
+}
+
+void
+justquit(int sig)
+{
+	exit(0);
+}
+
+
+/*
+ * Receive a file.
+ */
+void
+recvfile(struct formats *pf, struct tftphdr *oap, int oacklen)
+{
+	struct tftphdr *dp;
+	struct tftphdr *ap;    /* ack buffer */
+	int block = 0, acksize, n, size;
+
+	signal(SIGALRM, timer);
+	dp = w_init();
+	do {
+		timeout = 0;
+		
+		if (!block++ && oap) {
+		     ap = (struct tftphdr *)ackbuf;
+		     acksize = oacklen;
+		} else {
+		     ap = (struct tftphdr *)ackbuf;
+		     ap->th_opcode = htons((u_short)ACK);
+		     ap->th_block = htons((u_short)block);
+		     acksize = 4;
+		}
+		(void) setjmp(timeoutbuf);
+send_ack:
+		if (send(peer, ackbuf, acksize, 0) != acksize) {
+			syslog(LOG_ERR, "tftpd: write(ack): %m");
+			goto abort;
+		}
+		write_behind(file, pf->f_convert);
+		for ( ; ; ) {
+			alarm(rexmtval);
+			n = recv(peer, dp, PKTSIZE, 0);
+			alarm(0);
+			if (n < 0) {		/* really? */
+				syslog(LOG_ERR, "tftpd: read: %m");
+				goto abort;
+			}
+			dp->th_opcode = ntohs((u_short)dp->th_opcode);
+			dp->th_block = ntohs((u_short)dp->th_block);
+			if (dp->th_opcode == ERROR)
+				goto abort;
+			if (dp->th_opcode == DATA) {
+				if (dp->th_block == block) {
+					break;   /* normal */
+				}
+				/* Re-synchronize with the other side */
+				(void) synchnet(peer);
+				if (dp->th_block == (block-1))
+					goto send_ack;		/* rexmit */
+			}
+		}
+		/*  size = write(file, dp->th_data, n - 4); */
+		size = writeit(file, &dp, n - 4, pf->f_convert);
+		if (size != (n-4)) {			/* ahem */
+			if (size < 0) nak(errno + 100);
+			else nak(ENOSPACE);
+			goto abort;
+		}
+	} while (size == segsize);
+	write_behind(file, pf->f_convert);
+	(void) fclose(file);		/* close data file */
+
+	ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
+	ap->th_block = htons((u_short)(block));
+	(void) send(peer, ackbuf, 4, 0);
+
+	signal(SIGALRM, justquit);      /* just quit on timeout */
+	alarm(rexmtval);
+	n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
+	alarm(0);
+	if (n >= 4 &&			/* if read some data */
+	    dp->th_opcode == DATA &&    /* and got a data block */
+	    block == dp->th_block) {	/* then my last ack was lost */
+		(void) send(peer, ackbuf, 4, 0);     /* resend final ack */
+	}
+abort:
+	return;
+}
+
+struct errmsg {
+	int	e_code;
+	char	*e_msg;
+} errmsgs[] = {
+	{ EUNDEF,	"Undefined error code" },
+	{ ENOTFOUND,	"File not found" },
+	{ EACCESS,	"Access violation" },
+	{ ENOSPACE,	"Disk full or allocation exceeded" },
+	{ EBADOP,	"Illegal TFTP operation" },
+	{ EBADID,	"Unknown transfer ID" },
+	{ EEXISTS,	"File already exists" },
+	{ ENOUSER,	"No such user" },
+	{ EOPTNEG,	"Failure to negotiate RFC2347 options" },
+	{ -1,		0 }
+};
+
+/*
+ * Send a nak packet (error message).
+ * Error code passed in is one of the
+ * standard TFTP codes, or a UNIX errno
+ * offset by 100.
+ */
+void
+nak(int error)
+{
+	struct tftphdr *tp;
+	int length;
+	struct errmsg *pe;
+
+	tp = (struct tftphdr *)buf;
+	tp->th_opcode = htons((u_short)ERROR);
+	tp->th_code = htons((u_short)error);
+	for (pe = errmsgs; pe->e_code >= 0; pe++)
+		if (pe->e_code == error)
+			break;
+	if (pe->e_code < 0) {
+		pe->e_msg = strerror(error - 100);
+		tp->th_code = EUNDEF;   /* set 'undef' errorcode */
+	}
+	strcpy(tp->th_msg, pe->e_msg);
+	length = strlen(pe->e_msg);
+	tp->th_msg[length] = '\0';
+	length += 5;
+	if (send(peer, buf, length, 0) != length)
+		syslog(LOG_ERR, "nak: %m");
+}