+#ifndef lint
+static char sccsid[] = "@(#)ftpd.c 4.1 (Berkeley) 83/01/13";
+#endif
+
+/*
+ * FTP server.
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+
+#include <stdio.h>
+#include <signal.h>
+#include <wait.h>
+#include <pwd.h>
+#include <setjmp.h>
+#include <netdb.h>
+
+#include "ftp.h"
+
+extern int errno;
+extern char *sys_errlist[];
+extern char *crypt();
+extern char version[];
+extern char *home; /* pointer to home directory for glob */
+extern FILE *popen(), *fopen();
+extern int pclose(), fclose();
+
+struct sockaddr_in ctrl_addr;
+struct sockaddr_in data_source;
+struct sockaddr_in data_dest;
+struct sockaddr_in his_addr;
+
+struct hostent *hp;
+
+int data;
+jmp_buf errcatch;
+int logged_in;
+struct passwd *pw;
+int debug;
+int logging = 1;
+int guest;
+int type;
+int form;
+int stru; /* avoid C keyword */
+int mode;
+char hostname[32];
+char *remotehost;
+
+int lostconn();
+FILE *getdatasock(), *dataconn();
+char *ntoa();
+
+main(argc, argv)
+ int argc;
+ char *argv[];
+{
+ int ctrl, s, options = 0;
+ struct servent *sp;
+ union wait status;
+ char *cp;
+
+ sp = getservbyname("ftp", "tcp");
+ if (sp == 0) {
+ fprintf(stderr, "ftpd: fpt/tcp: unknown service\n");
+ exit(1);
+ }
+ ctrl_addr.sin_port = sp->s_port;
+ data_source.sin_port = htons(ntohs(sp->s_port) - 1);
+ signal(SIGPIPE, lostconn);
+ debug = 0;
+ argc--, argv++;
+ while (argc > 0 && *argv[0] == '-') {
+ for (cp = &argv[0][1]; *cp; cp++) switch (*cp) {
+
+ case 'd':
+ debug = 1;
+ options |= SO_DEBUG;
+ break;
+
+ default:
+ fprintf(stderr, "Unknown flag -%c ignored.\n", cp);
+ break;
+ }
+ argc--, argv++;
+ }
+#ifndef DEBUG
+ if (fork())
+ exit(0);
+ for (s = 0; s < 10; s++)
+ if (s != 2) /* don't screw stderr */
+ (void) close(s);
+ (void) open("/dev/null", 0);
+ (void) dup2(0, 1);
+ { int tt = open("/dev/tty", 2);
+ if (tt > 0) {
+ ioctl(tt, TIOCNOTTY, 0);
+ close(tt);
+ }
+ }
+#endif
+ while ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+ perror("ftpd: socket");
+ sleep(5);
+ }
+ while (bind(s, &ctrl_addr, sizeof (ctrl_addr), 0) < 0) {
+ perror("ftpd: bind");
+ sleep(5);
+ }
+ for (;;) {
+ int hisaddrlen = sizeof (his_addr);
+
+ ctrl = accept(s, &his_addr, &hisaddrlen, 0);
+ if (ctrl < 0) {
+ perror("ftpd: accept");
+ sleep(5);
+ continue;
+ }
+ data_dest = his_addr;
+ if (fork() == 0) {
+ if (logging)
+ dolog(&his_addr);
+ close(s);
+ dup2(ctrl, 0), close(ctrl), dup2(0, 1);
+ /* do telnet option negotiation here */
+ logged_in = 0;
+ data = -1;
+ gethostname(hostname, sizeof (hostname));
+ reply(220, "%s FTP server (%s) ready.",
+ hostname, version);
+ for (;;) {
+ setjmp(errcatch);
+ yyparse();
+ }
+ }
+ close(ctrl);
+ while (wait3(status, WNOHANG, 0) > 0)
+ continue;
+ }
+}
+
+lostconn()
+{
+
+ fatal("Connection closed.");
+}
+
+pass(passwd)
+ char *passwd;
+{
+ char *xpasswd;
+
+ if (logged_in || pw == NULL) {
+ reply(503, "Login with USER first.");
+ return;
+ }
+ if (!guest) { /* "ftp" is only account allowed no password */
+ xpasswd = crypt(passwd, pw->pw_passwd);
+ if (strcmp(xpasswd, pw->pw_passwd) != 0) {
+ reply(530, "Login incorrect.");
+ pw = NULL;
+ return;
+ }
+ }
+ home = pw->pw_dir; /* home dir for globbing */
+ setreuid(-1, pw->pw_uid);
+ setregid(-1, pw->pw_gid);
+ initgroups(pw->pw_name, pw->pw_gid);
+ if (chdir(pw->pw_dir)) {
+ reply(550, "User %s: can't change directory to $s.",
+ pw->pw_name, pw->pw_dir);
+ pw = NULL;
+ return;
+ }
+ if (guest && chroot(pw->pw_dir) < 0){
+ reply(550, "Can't set guest privileges.");
+ pw = NULL;
+ return;
+ }
+ if (!guest)
+ reply(230, "User %s logged in.", pw->pw_name);
+ else
+ reply(230, "Guest login ok, access restrictions apply.");
+ logged_in = 1;
+}
+
+retrieve(cmd, name)
+ char *cmd, *name;
+{
+ FILE *fin, *dout;
+ struct stat st;
+ int (*closefunc)();
+
+ if (cmd == 0) {
+ if (*name == '!')
+ fin = popen(name + 1, "r"), closefunc = pclose;
+ else
+ fin = fopen(name, "r"), closefunc = fclose;
+ } else {
+ char line[BUFSIZ];
+
+ sprintf(line, cmd, name);
+ fin = popen(line, "r"), closefunc = pclose;
+ }
+ if (fin == NULL) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+ st.st_size = 0;
+ if (cmd == 0 &&
+ (stat(name, &st) < 0 || (st.st_mode&S_IFMT) != S_IFREG)) {
+ reply(550, "%s: not a plain file.", name);
+ goto done;
+ }
+ dout = dataconn(name, st.st_size, "w");
+ if (dout == NULL)
+ goto done;
+ if (!send_data(fin, dout) || ferror(dout))
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ else
+ reply(226, "Transfer complete.");
+ if (mode == MODE_S)
+ /* indicate EOF by closing connection */
+ fclose(dout), data = -1;
+done:
+ (*closefunc)(fin);
+}
+
+store(name, mode)
+ char *name, *mode;
+{
+ FILE *fout, *din;
+ int (*closefunc)();
+
+ if (name[0] == '!')
+ fout = popen(&name[1], "w"), closefunc = pclose;
+ else
+ fout = fopen(name, mode), closefunc = fclose;
+ if (fout == NULL) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+ din = dataconn(name, -1, "r");
+ if (din == NULL)
+ goto done;
+ if (!receive_data(din, fout) || ferror(fout))
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ else
+ reply(226, "Transfer complete.");
+ fclose(din), data = -1;
+done:
+ (*closefunc)(fout);
+}
+
+FILE *
+getdatasock(mode)
+ char *mode;
+{
+ int retrytime, s;
+
+ if (data >= 0)
+ return (fdopen(data, mode));
+ retrytime = 1;
+ while ((s = socket(AF_INET, SOCK_STREAM, 0, 0)) < 0) {
+ if (retrytime < 5) {
+ sleep(retrytime);
+ retrytime <<= 1;
+ continue;
+ }
+ return (NULL);
+ }
+ retrytime = 1;
+ seteuid(0);
+ while (bind(s, &data_source, sizeof (data_source), 0) < 0) {
+ if (retrytime < 5) {
+ sleep(retrytime);
+ retrytime <<= 1;
+ continue;
+ }
+ seteuid(0);
+ close(s);
+ return (NULL);
+ }
+ seteuid(0);
+ return (fdopen(s, mode));
+}
+
+FILE *
+dataconn(name, size, mode)
+ char *name;
+ int size;
+ char *mode;
+{
+ char sizebuf[32];
+ FILE *file;
+
+ if (size >= 0)
+ sprintf(sizebuf, " (%d bytes)", size);
+ else
+ (void) strcpy(sizebuf, "");
+ if (data >= 0) {
+ reply(125, "Using existing data connection for %s%s.",
+ name, sizebuf);
+ return (fdopen(data, mode));
+ }
+ reply(150, "Opening data connection for %s (%s,%d)%s.",
+ name, ntoa(data_dest.sin_addr.s_addr),
+ ntohs(data_dest.sin_port), sizebuf);
+ file = getdatasock(mode);
+ if (file == NULL) {
+ reply(425, "Can't create data socket (%s,%d): %s.",
+ ntoa(data_source.sin_addr),
+ ntohs(data_source.sin_port),
+ sys_errlist[errno]);
+ return (NULL);
+ }
+ data = fileno(file);
+ if (connect(data, &data_dest, sizeof (data_dest), 0) < 0) {
+ reply(425, "Can't build data connection: %s.",
+ sys_errlist[errno]);
+ (void) fclose(file);
+ data = -1;
+ return (NULL);
+ }
+ return (file);
+}
+
+/*
+ * Tranfer the contents of "instr" to
+ * "outstr" peer using the appropriate
+ * encapulation of the date subject
+ * to Mode, Structure, and Type.
+ *
+ * NB: Form isn't handled.
+ */
+send_data(instr, outstr)
+ FILE *instr, *outstr;
+{
+ register int c;
+ int netfd, filefd, cnt;
+ char buf[BUFSIZ];
+
+ switch (type) {
+
+ case TYPE_A:
+ while ((c = getc(instr)) != EOF) {
+ if (c == '\n')
+ putc('\r', outstr);
+ if (putc(c, outstr) == EOF)
+ return (1);
+ }
+ return (0);
+
+ case TYPE_I:
+ case TYPE_L:
+ netfd = fileno(outstr);
+ filefd = fileno(instr);
+
+ while ((cnt = read(filefd, buf, sizeof buf)) > 0)
+ if (write(netfd, buf, cnt) < 0)
+ return (1);
+ return (cnt < 0);
+ }
+ reply(504,"Unimplemented TYPE %d in send_data", type);
+ return (1);
+}
+
+/*
+ * Transfer data from peer to
+ * "outstr" using the appropriate
+ * encapulation of the data subject
+ * to Mode, Structure, and Type.
+ *
+ * N.B.: Form isn't handled.
+ */
+receive_data(instr, outstr)
+ FILE *instr, *outstr;
+{
+ register int c;
+ int cr, escape, eof;
+ int netfd, filefd, cnt;
+ char buf[BUFSIZ];
+
+
+ switch (type) {
+
+ case TYPE_I:
+ case TYPE_L:
+ netfd = fileno(instr);
+ netfd = fileno(outstr);
+ while ((cnt = read(netfd, buf, sizeof buf)) > 0)
+ if (write(filefd, buf, cnt) < 0)
+ return (1);
+ return (cnt < 0);
+
+ case TYPE_E:
+ reply(504, "TYPE E not implemented.");
+ return (1);
+
+ case TYPE_A:
+ cr = 0;
+ while ((c = getc(instr)) != EOF) {
+ if (cr) {
+ if (c != '\r' && c != '\n')
+ putc('\r', outstr);
+ putc(c, outstr);
+ cr = c == '\r';
+ continue;
+ }
+ if (c == '\r') {
+ cr = 1;
+ continue;
+ }
+ putc(c, outstr);
+ }
+ if (cr)
+ putc('\r', outstr);
+ return (0);
+ }
+ fatal("Unknown type in receive_data.");
+ /*NOTREACHED*/
+}
+
+fatal(s)
+ char *s;
+{
+ reply(451, "Error in server: %s\n", s);
+ reply(221, "Closing connection due to server error.");
+ exit(0);
+}
+
+reply(n, s, args)
+ int n;
+ char *s;
+{
+
+ printf("%d ", n);
+ _doprnt(s, &args, stdout);
+ printf("\r\n");
+ fflush(stdout);
+ if (debug) {
+ fprintf(stderr, "<--- %d ", n);
+ _doprnt(s, &args, stderr);
+ fprintf(stderr, "\n");
+ fflush(stderr);
+ }
+}
+
+lreply(n, s, args)
+ int n;
+ char *s;
+{
+ printf("%d-", n);
+ _doprnt(s, &args, stdout);
+ printf("\r\n");
+ fflush(stdout);
+ if (debug) {
+ fprintf(stderr, "<--- %d-", n);
+ _doprnt(s, &args, stderr);
+ fprintf(stderr, "\n");
+ }
+}
+
+replystr(s)
+ char *s;
+{
+ printf("%s\r\n", s);
+ fflush(stdout);
+ if (debug)
+ fprintf(stderr, "<--- %s\n", s);
+}
+
+ack(s)
+ char *s;
+{
+ reply(200, "%s command okay.", s);
+}
+
+nack(s)
+ char *s;
+{
+ reply(502, "%s command not implemented.", s);
+}
+
+yyerror()
+{
+ reply(500, "Command not understood.");
+}
+
+delete(name)
+ char *name;
+{
+ struct stat st;
+
+ if (stat(name, &st) < 0) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+ if ((st.st_mode&S_IFMT) == S_IFDIR) {
+ if (rmdir(name) < 0) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+ goto done;
+ }
+ if (unlink(name) < 0) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+done:
+ ack("DELE");
+}
+
+cwd(path)
+ char *path;
+{
+
+ if (chdir(path) < 0) {
+ reply(550, "%s: %s.", path, sys_errlist[errno]);
+ return;
+ }
+ ack("CWD");
+}
+
+do_mkdir(name)
+ char *name;
+{
+
+ if (mkdir(name, 0777) < 0) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+ ack("MKDIR");
+}
+
+do_rmdir(name)
+ char *name;
+{
+
+ if (rmdir(name) < 0) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return;
+ }
+ ack("RMDIR");
+}
+
+do_pwd()
+{
+ char path[1024];
+ char *p;
+
+ if (getwd(path) == NULL) {
+ reply(451, "%s.", path);
+ return;
+ }
+ reply(251, "\"%s\" is current directory.", path);
+}
+
+char *
+renamefrom(name)
+ char *name;
+{
+ struct stat st;
+
+ if (stat(name, &st) < 0) {
+ reply(550, "%s: %s.", name, sys_errlist[errno]);
+ return ((char *)0);
+ }
+ ack("RNFR");
+ return (name);
+}
+
+renamecmd(from, to)
+ char *from, *to;
+{
+
+ if (rename(from, to) < 0) {
+ reply(550, "rename: %s.", sys_errlist[errno]);
+ return;
+ }
+ ack("RNTO");
+}
+
+int guest;
+/*
+ * Test pathname for guest-user safety.
+ */
+inappropriate_request(name)
+ char *name;
+{
+ int bogus = 0, depth = 0, length = strlen(name);
+ char *p, *s;
+
+ if (!guest)
+ return (0);
+ if (name[0] == '/' || name[0] == '|')
+ bogus = 1;
+ for (p = name; p < name+length;) {
+ s = p; /* start of token */
+ while ( *p && *p!= '/')
+ p++;
+ *p = 0;
+ if (strcmp(s, "..") == 0)
+ depth -= 1; /* backing up */
+ else if (strcmp(s, ".") == 0)
+ depth += 0; /* no change */
+ else
+ depth += 1; /* descending */
+ if (depth < 0) {
+ bogus = 1;
+ break;
+ }
+ }
+ if (bogus)
+ reply(553, "%s: pathname disallowed guest users", name);
+ return (bogus);
+}
+
+/*
+ * Convert network-format internet address
+ * to base 256 d.d.d.d representation.
+ */
+char *
+ntoa(in)
+ struct in_addr in;
+{
+ static char b[18];
+ register char *p;
+
+ in.s_addr = ntohl(in.s_addr);
+ p = (char *)∈
+#define UC(b) (((int)b)&0xff)
+ sprintf(b, "%d.%d.%d.%d", UC(p[0]), UC(p[1]), UC(p[2]), UC(p[3]));
+ return (b);
+}
+
+dolog(sin)
+ struct sockaddr_in *sin;
+{
+ struct hostent *hp = gethostbyaddr(&sin->sin_addr,
+ sizeof (struct in_addr), AF_INET);
+ char *remotehost;
+ time_t t;
+
+ if (hp)
+ remotehost = hp->h_name;
+ else
+ remotehost = "UNKNOWNHOST";
+ t = time(0);
+ fprintf(stderr,"FTP %d: connection from %s at %s",
+ getpid(), remotehost, ctime(&t));
+ fflush(stderr);
+}
projects / unix-history / commitdiff