+/* tftpd.c 4.1 82/08/16 */
+
+/*
+ * Trivial file transfer protocol server.
+ */
+#include <sys/types.h>
+#include <net/in.h>
+#include <sys/socket.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+#include <stat.h>
+#include <stdio.h>
+#include <wait.h>
+#include <errno.h>
+#include <ctype.h>
+#include "tftp.h"
+
+#define DEBUG 1
+
+extern int errno;
+struct sockaddr_in sin = { AF_INET, IPPORT_TFTP };
+int f;
+int options;
+char buf[BUFSIZ];
+
+main(argc, argv)
+ char *argv[];
+{
+ union wait status;
+ struct sockaddr_in from;
+ register struct tftphdr *tp;
+ register int n;
+
+#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
+#if vax || pdp11
+ sin.sin_port = htons(sin.sin_port);
+#endif
+ argc--, argv++;
+ if (argc > 0 && !strcmp(argv[0], "-d"))
+ options |= SO_DEBUG;
+ for (;;) {
+ errno = 0;
+ f = socket(SOCK_DGRAM, 0, &sin, options);
+ if (f < 0) {
+ perror("socket");
+ sleep(5);
+ continue;
+ }
+again:
+ n = receive(f, &from, buf, sizeof (buf));
+ if (n <= 0) {
+ if (n < 0)
+ perror("receive");
+ goto again;
+ }
+ tp = (struct tftphdr *)buf;
+#if vax || pdp11
+ tp->th_opcode = ntohs(tp->th_opcode);
+#endif
+ if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
+ if (fork() == 0)
+ tftp(&from, tp, n);
+ (void) close(f);
+#ifdef notdef
+ while (wait3(status, WNOHANG, 0) > 0)
+#else
+ while (wait3(status, 0, 0) > 0)
+ continue;
+ }
+}
+
+int validate_access();
+int sendfile(), recvfile();
+
+struct formats {
+ char *f_mode;
+ int (*f_validate)();
+ int (*f_send)();
+ int (*f_recv)();
+} formats[] = {
+ { "netascii", validate_access, sendfile, recvfile },
+ { "octet", validate_access, sendfile, recvfile },
+#ifdef notdef
+ { "mail", validate_user, sendmail, recvmail },
+#endif
+ { 0 }
+};
+
+int fd; /* file being transferred */
+
+/*
+ * Handle initial connection protocol.
+ */
+tftp(client, tp, size)
+ struct sockaddr_in *client;
+ struct tftphdr *tp;
+ int size;
+{
+ register char *cp;
+ int first = 1, ecode;
+ register struct formats *pf;
+ char *filename, *mode;
+
+ if (connect(f, client) < 0) {
+ perror("connect");
+ exit(1);
+ }
+ filename = cp = tp->th_stuff;
+again:
+ while (cp < buf + size) {
+ if (*cp == '\0')
+ break;
+ cp++;
+ }
+ if (*cp != '\0') {
+ nak(EBADOP);
+ exit(1);
+ }
+ if (first) {
+ mode = ++cp;
+ first = 0;
+ goto again;
+ }
+ for (cp = mode; *cp; cp++)
+ if (isupper(*cp))
+ *cp = tolower(*cp);
+ for (pf = formats; pf->f_mode; pf++)
+ if (strcmp(pf->f_mode, mode) == 0)
+ break;
+ if (pf->f_mode == 0) {
+ nak(EBADOP);
+ exit(1);
+ }
+ ecode = (*pf->f_validate)(filename, client, tp->th_opcode);
+ if (ecode) {
+ nak(ecode);
+ exit(1);
+ }
+ if (tp->th_opcode == WRQ)
+ (*pf->f_recv)(pf);
+ else
+ (*pf->f_send)(pf);
+ exit(0);
+}
+
+/*
+ * Validate file access. Since we
+ * have no uid or gid, for now require
+ * file to exist and be publicly
+ * readable/writable.
+ * Note also, full path name must be
+ * given as we have no login directory.
+ */
+validate_access(file, client, mode)
+ char *file;
+ struct sockaddr_in *client;
+ int mode;
+{
+ struct stat stbuf;
+
+ if (*file != '/')
+ return (EACCESS);
+ if (stat(file, &stbuf) < 0)
+ return (errno == ENOENT ? ENOTFOUND : EACCESS);
+ if (mode == RRQ) {
+ if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)
+ return (EACCESS);
+ } else {
+ if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
+ return (EACCESS);
+ }
+ fd = open(file, mode == RRQ ? 0 : 1);
+ if (fd < 0)
+ return (errno + 100);
+ return (0);
+}
+
+int timeout;
+
+timer()
+{
+ timeout += TIMEOUT;
+ if (timeout >= MAXTIMEOUT)
+ exit(1);
+ alarm(TIMEOUT);
+}
+
+/*
+ * Send the requested file.
+ */
+sendfile(pf)
+ struct format *pf;
+{
+ register struct tftphdr *tp;
+ register int block = 1, size, n;
+
+ sigset(SIGALRM, timer);
+ tp = (struct tftphdr *)buf;
+ do {
+ size = read(fd, tp->th_data, SEGSIZE);
+ if (size < 0) {
+ nak(errno + 100);
+ break;
+ }
+ tp->th_opcode = htons((u_short)DATA);
+ tp->th_block = htons((u_short)block);
+ timeout = 0;
+ alarm(TIMEOUT);
+rexmt:
+ if (write(f, buf, size + 4) != size + 4) {
+ perror("send");
+ break;
+ }
+again:
+ n = read(f, buf, sizeof (buf));
+ if (n <= 0) {
+ if (n == 0)
+ goto again;
+ if (errno == EINTR)
+ goto rexmt;
+ alarm(0);
+ perror("receive");
+ break;
+ }
+ alarm(0);
+#if vax || pdp11
+ tp->th_opcode = ntohs(tp->th_opcode);
+ tp->th_block = ntohs(tp->th_block);
+#endif
+ if (tp->th_opcode == ERROR)
+ break;
+ if (tp->th_opcode != ACK || tp->th_block != block)
+ goto again;
+ block++;
+ } while (size == SEGSIZE);
+ (void) close(fd);
+}
+
+/*
+ * Receive a file.
+ */
+recvfile(pf)
+ struct format *pf;
+{
+ register struct tftphdr *tp;
+ register int block = 0, n, size;
+
+ sigset(SIGALRM, timer);
+ tp = (struct tftphdr *)buf;
+ do {
+ timeout = 0;
+ alarm(TIMEOUT);
+ tp->th_opcode = htons((u_short)ACK);
+ tp->th_block = htons((u_short)block);
+ block++;
+rexmt:
+ if (write(f, buf, 4) != 4) {
+ perror("ack");
+ break;
+ }
+again:
+ n = read(f, buf, sizeof (buf));
+ if (n <= 0) {
+ if (n == 0)
+ goto again;
+ if (errno == EINTR)
+ goto rexmt;
+ alarm(0);
+ perror("receive");
+ break;
+ }
+ alarm(0);
+#if vax || pdp11
+ tp->th_opcode = ntohs(tp->th_opcode);
+ tp->th_block = ntohs(tp->th_block);
+#endif
+ if (tp->th_opcode == ERROR)
+ break;
+ if (tp->th_opcode != DATA || block != tp->th_block)
+ goto again;
+ size = write(fd, tp->th_data, n - 4);
+ if (size < 0) {
+ nak(errno + 100);
+ break;
+ }
+ } while (size == SEGSIZE);
+ tp->th_opcode = htons((u_short)ACK);
+ tp->th_block = htons((u_short)(block));
+ (void) write(f, buf, 4);
+ (void) close(fd);
+}
+
+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" },
+ { -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.
+ */
+nak(error)
+ int error;
+{
+ register struct tftphdr *tp;
+ int length;
+ register struct errmsg *pe;
+ extern char *sys_errlist[];
+
+ 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 = sys_errlist[error - 100];
+ strcpy(tp->th_msg, pe->e_msg);
+ length = strlen(pe->e_msg);
+ tp->th_msg[length] = '\0';
+ length += 5;
+ if (write(f, buf, length) != length)
+ perror("nak");
+}
projects / unix-history / commitdiff