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-rw-r--r--usr.sbin/inetd/builtins.c814
1 files changed, 814 insertions, 0 deletions
diff --git a/usr.sbin/inetd/builtins.c b/usr.sbin/inetd/builtins.c
new file mode 100644
index 0000000..3ccdab0
--- /dev/null
+++ b/usr.sbin/inetd/builtins.c
@@ -0,0 +1,814 @@
+/*-
+ * Copyright (c) 1983, 1991, 1993, 1994
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/filio.h>
+#include <sys/ioccom.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/sysctl.h>
+#include <sys/ucred.h>
+#include <sys/uio.h>
+#include <sys/utsname.h>
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include "inetd.h"
+
+void chargen_dg(int, struct servtab *);
+void chargen_stream(int, struct servtab *);
+void daytime_dg(int, struct servtab *);
+void daytime_stream(int, struct servtab *);
+void discard_dg(int, struct servtab *);
+void discard_stream(int, struct servtab *);
+void echo_dg(int, struct servtab *);
+void echo_stream(int, struct servtab *);
+static int getline(int, char *, int);
+void iderror(int, int, int, const char *);
+void ident_stream(int, struct servtab *);
+void initring(void);
+uint32_t machtime(void);
+void machtime_dg(int, struct servtab *);
+void machtime_stream(int, struct servtab *);
+
+char ring[128];
+char *endring;
+
+
+struct biltin biltins[] = {
+ /* Echo received data */
+ { "echo", SOCK_STREAM, 1, -1, echo_stream },
+ { "echo", SOCK_DGRAM, 0, 1, echo_dg },
+
+ /* Internet /dev/null */
+ { "discard", SOCK_STREAM, 1, -1, discard_stream },
+ { "discard", SOCK_DGRAM, 0, 1, discard_dg },
+
+ /* Return 32 bit time since 1900 */
+ { "time", SOCK_STREAM, 0, -1, machtime_stream },
+ { "time", SOCK_DGRAM, 0, 1, machtime_dg },
+
+ /* Return human-readable time */
+ { "daytime", SOCK_STREAM, 0, -1, daytime_stream },
+ { "daytime", SOCK_DGRAM, 0, 1, daytime_dg },
+
+ /* Familiar character generator */
+ { "chargen", SOCK_STREAM, 1, -1, chargen_stream },
+ { "chargen", SOCK_DGRAM, 0, 1, chargen_dg },
+
+ { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux },
+
+ { "auth", SOCK_STREAM, 1, -1, ident_stream },
+
+ { NULL, 0, 0, 0, NULL }
+};
+
+/*
+ * RFC864 Character Generator Protocol. Generates character data without
+ * any regard for input.
+ */
+
+void
+initring(void)
+{
+ int i;
+
+ endring = ring;
+
+ for (i = 0; i <= 128; ++i)
+ if (isprint(i))
+ *endring++ = i;
+}
+
+/* Character generator
+ * The RFC says that we should send back a random number of
+ * characters chosen from the range 0 to 512. We send LINESIZ+2.
+ */
+/* ARGSUSED */
+void
+chargen_dg(int s, struct servtab *sep)
+{
+ struct sockaddr_storage ss;
+ static char *rs;
+ int len;
+ socklen_t size;
+ char text[LINESIZ+2];
+
+ if (endring == 0) {
+ initring();
+ rs = ring;
+ }
+
+ size = sizeof(ss);
+ if (recvfrom(s, text, sizeof(text), 0,
+ (struct sockaddr *)&ss, &size) < 0)
+ return;
+
+ if (check_loop((struct sockaddr *)&ss, sep))
+ return;
+
+ if ((len = endring - rs) >= LINESIZ)
+ memmove(text, rs, LINESIZ);
+ else {
+ memmove(text, rs, len);
+ memmove(text + len, ring, LINESIZ - len);
+ }
+ if (++rs == endring)
+ rs = ring;
+ text[LINESIZ] = '\r';
+ text[LINESIZ + 1] = '\n';
+ (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
+}
+
+/* Character generator */
+/* ARGSUSED */
+void
+chargen_stream(int s, struct servtab *sep)
+{
+ int len;
+ char *rs, text[LINESIZ+2];
+
+ inetd_setproctitle(sep->se_service, s);
+
+ if (!endring) {
+ initring();
+ rs = ring;
+ }
+
+ text[LINESIZ] = '\r';
+ text[LINESIZ + 1] = '\n';
+ for (rs = ring;;) {
+ if ((len = endring - rs) >= LINESIZ)
+ memmove(text, rs, LINESIZ);
+ else {
+ memmove(text, rs, len);
+ memmove(text + len, ring, LINESIZ - len);
+ }
+ if (++rs == endring)
+ rs = ring;
+ if (write(s, text, sizeof(text)) != sizeof(text))
+ break;
+ }
+ exit(0);
+}
+
+/*
+ * RFC867 Daytime Protocol. Sends the current date and time as an ascii
+ * character string without any regard for input.
+ */
+
+/* Return human-readable time of day */
+/* ARGSUSED */
+void
+daytime_dg(int s, struct servtab *sep)
+{
+ char buffer[256];
+ time_t now;
+ struct sockaddr_storage ss;
+ socklen_t size;
+
+ now = time((time_t *) 0);
+
+ size = sizeof(ss);
+ if (recvfrom(s, buffer, sizeof(buffer), 0,
+ (struct sockaddr *)&ss, &size) < 0)
+ return;
+
+ if (check_loop((struct sockaddr *)&ss, sep))
+ return;
+
+ (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
+ (void) sendto(s, buffer, strlen(buffer), 0,
+ (struct sockaddr *)&ss, size);
+}
+
+/* Return human-readable time of day */
+/* ARGSUSED */
+void
+daytime_stream(int s, struct servtab *sep __unused)
+{
+ char buffer[256];
+ time_t now;
+
+ now = time((time_t *) 0);
+
+ (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
+ (void) send(s, buffer, strlen(buffer), MSG_EOF);
+}
+
+/*
+ * RFC863 Discard Protocol. Any data received is thrown away and no response
+ * is sent.
+ */
+
+/* Discard service -- ignore data */
+/* ARGSUSED */
+void
+discard_dg(int s, struct servtab *sep __unused)
+{
+ char buffer[BUFSIZE];
+
+ (void) read(s, buffer, sizeof(buffer));
+}
+
+/* Discard service -- ignore data */
+/* ARGSUSED */
+void
+discard_stream(int s, struct servtab *sep)
+{
+ int ret;
+ char buffer[BUFSIZE];
+
+ inetd_setproctitle(sep->se_service, s);
+ while (1) {
+ while ((ret = read(s, buffer, sizeof(buffer))) > 0)
+ ;
+ if (ret == 0 || errno != EINTR)
+ break;
+ }
+ exit(0);
+}
+
+/*
+ * RFC862 Echo Protocol. Any data received is sent back to the sender as
+ * received.
+ */
+
+/* Echo service -- echo data back */
+/* ARGSUSED */
+void
+echo_dg(int s, struct servtab *sep)
+{
+ char buffer[65536]; /* Should be sizeof(max datagram). */
+ int i;
+ socklen_t size;
+ struct sockaddr_storage ss;
+
+ size = sizeof(ss);
+ if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
+ (struct sockaddr *)&ss, &size)) < 0)
+ return;
+
+ if (check_loop((struct sockaddr *)&ss, sep))
+ return;
+
+ (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
+}
+
+/* Echo service -- echo data back */
+/* ARGSUSED */
+void
+echo_stream(int s, struct servtab *sep)
+{
+ char buffer[BUFSIZE];
+ int i;
+
+ inetd_setproctitle(sep->se_service, s);
+ while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
+ write(s, buffer, i) > 0)
+ ;
+ exit(0);
+}
+
+/*
+ * RFC1413 Identification Protocol. Given a TCP port number pair, return a
+ * character string which identifies the owner of that connection on the
+ * server's system. Extended to allow for ~/.fakeid support and ~/.noident
+ * support.
+ */
+
+/* RFC 1413 says the following are the only errors you can return. */
+#define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
+#define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */
+#define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */
+#define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
+
+/* Generic ident_stream error-sending func */
+/* ARGSUSED */
+void
+iderror(int lport, int fport, int s, const char *er)
+{
+ char *p;
+
+ asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
+ if (p == NULL) {
+ syslog(LOG_ERR, "asprintf: %m");
+ exit(EX_OSERR);
+ }
+ send(s, p, strlen(p), MSG_EOF);
+ free(p);
+
+ exit(0);
+}
+
+/* Ident service (AKA "auth") */
+/* ARGSUSED */
+void
+ident_stream(int s, struct servtab *sep)
+{
+ struct utsname un;
+ struct stat sb;
+ struct sockaddr_in sin4[2];
+#ifdef INET6
+ struct sockaddr_in6 sin6[2];
+#endif
+ struct sockaddr_storage ss[2];
+ struct xucred uc;
+ struct timeval tv = {
+ 10,
+ 0
+ }, to;
+ struct passwd *pw = NULL;
+ fd_set fdset;
+ char buf[BUFSIZE], *p, **av, *osname = NULL, e;
+ char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
+ socklen_t socklen;
+ ssize_t ssize;
+ size_t size, bufsiz;
+ int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
+ int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
+ u_short lport, fport;
+
+ inetd_setproctitle(sep->se_service, s);
+ /*
+ * Reset getopt() since we are a fork() but not an exec() from
+ * a parent which used getopt() already.
+ */
+ optind = 1;
+ optreset = 1;
+ /*
+ * Take the internal argument vector and count it out to make an
+ * argument count for getopt. This can be used for any internal
+ * service to read arguments and use getopt() easily.
+ */
+ for (av = sep->se_argv; *av; av++)
+ argc++;
+ if (argc) {
+ int sec, usec;
+ size_t i;
+ u_int32_t rnd32;
+
+ while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
+ switch (c) {
+ case 'd':
+ if (!gflag)
+ strlcpy(idbuf, optarg, sizeof(idbuf));
+ break;
+ case 'f':
+ fflag = 1;
+ break;
+ case 'F':
+ fflag = 1;
+ Fflag=1;
+ break;
+ case 'g':
+ gflag = 1;
+ rnd32 = 0; /* Shush, compiler. */
+ /*
+ * The number of bits in "rnd32" divided
+ * by the number of bits needed per iteration
+ * gives a more optimal way to reload the
+ * random number only when necessary.
+ *
+ * 32 bits from arc4random corresponds to
+ * about 6 base-36 digits, so we reseed evey 6.
+ */
+ for (i = 0; i < sizeof(idbuf) - 1; i++) {
+ static const char *const base36 =
+ "0123456789"
+ "abcdefghijklmnopqrstuvwxyz";
+ if (i % 6 == 0)
+ rnd32 = arc4random();
+ idbuf[i] = base36[rnd32 % 36];
+ rnd32 /= 36;
+ }
+ idbuf[i] = '\0';
+ break;
+ case 'i':
+ iflag = 1;
+ break;
+ case 'n':
+ nflag = 1;
+ break;
+ case 'o':
+ osname = optarg;
+ break;
+ case 'r':
+ rflag = 1;
+ break;
+ case 't':
+ switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
+ case 2:
+ tv.tv_usec = usec;
+ /* FALLTHROUGH */
+ case 1:
+ tv.tv_sec = sec;
+ break;
+ default:
+ if (debug)
+ warnx("bad -t argument");
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ if (osname == NULL) {
+ if (uname(&un) == -1)
+ iderror(0, 0, s, ID_UNKNOWN);
+ osname = un.sysname;
+ }
+
+ /*
+ * We're going to prepare for and execute reception of a
+ * packet of data from the user. The data is in the format
+ * "local_port , foreign_port\r\n" (with local being the
+ * server's port and foreign being the client's.)
+ */
+ gettimeofday(&to, NULL);
+ to.tv_sec += tv.tv_sec;
+ to.tv_usec += tv.tv_usec;
+ if (to.tv_usec >= 1000000) {
+ to.tv_usec -= 1000000;
+ to.tv_sec++;
+ }
+
+ size = 0;
+ bufsiz = sizeof(buf) - 1;
+ FD_ZERO(&fdset);
+ while (bufsiz > 0) {
+ gettimeofday(&tv, NULL);
+ tv.tv_sec = to.tv_sec - tv.tv_sec;
+ tv.tv_usec = to.tv_usec - tv.tv_usec;
+ if (tv.tv_usec < 0) {
+ tv.tv_usec += 1000000;
+ tv.tv_sec--;
+ }
+ if (tv.tv_sec < 0)
+ break;
+ FD_SET(s, &fdset);
+ if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
+ iderror(0, 0, s, ID_UNKNOWN);
+ if (ioctl(s, FIONREAD, &onreadlen) == -1)
+ iderror(0, 0, s, ID_UNKNOWN);
+ if ((size_t)onreadlen > bufsiz)
+ onreadlen = bufsiz;
+ ssize = read(s, &buf[size], (size_t)onreadlen);
+ if (ssize == -1)
+ iderror(0, 0, s, ID_UNKNOWN);
+ else if (ssize == 0)
+ break;
+ bufsiz -= ssize;
+ size += ssize;
+ if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
+ break;
+ }
+ buf[size] = '\0';
+ /* Read two characters, and check for a delimiting character */
+ if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
+ iderror(0, 0, s, ID_INVALID);
+
+ /* Send garbage? */
+ if (gflag)
+ goto printit;
+
+ /*
+ * If not "real" (-r), send a HIDDEN-USER error for everything.
+ * If -d is used to set a fallback username, this is used to
+ * override it, and the fallback is returned instead.
+ */
+ if (!rflag) {
+ if (*idbuf == '\0')
+ iderror(lport, fport, s, ID_HIDDEN);
+ goto printit;
+ }
+
+ /*
+ * We take the input and construct an array of two sockaddr_ins
+ * which contain the local address information and foreign
+ * address information, respectively, used to look up the
+ * credentials for the socket (which are returned by the
+ * sysctl "net.inet.tcp.getcred" when we call it.)
+ */
+ socklen = sizeof(ss[0]);
+ if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ socklen = sizeof(ss[1]);
+ if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ if (ss[0].ss_family != ss[1].ss_family)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ size = sizeof(uc);
+ switch (ss[0].ss_family) {
+ case AF_INET:
+ sin4[0] = *(struct sockaddr_in *)&ss[0];
+ sin4[0].sin_port = htons(lport);
+ sin4[1] = *(struct sockaddr_in *)&ss[1];
+ sin4[1].sin_port = htons(fport);
+ if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
+ sizeof(sin4)) == -1)
+ getcredfail = errno;
+ break;
+#ifdef INET6
+ case AF_INET6:
+ sin6[0] = *(struct sockaddr_in6 *)&ss[0];
+ sin6[0].sin6_port = htons(lport);
+ sin6[1] = *(struct sockaddr_in6 *)&ss[1];
+ sin6[1].sin6_port = htons(fport);
+ if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
+ sizeof(sin6)) == -1)
+ getcredfail = errno;
+ break;
+#endif
+ default: /* should not reach here */
+ getcredfail = EAFNOSUPPORT;
+ break;
+ }
+ if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) {
+ if (*idbuf == '\0')
+ iderror(lport, fport, s,
+ getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
+ goto printit;
+ }
+
+ /* Look up the pw to get the username and home directory*/
+ errno = 0;
+ pw = getpwuid(uc.cr_uid);
+ if (pw == NULL)
+ iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
+
+ if (iflag)
+ snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
+ else
+ strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
+
+ /*
+ * If enabled, we check for a file named ".noident" in the user's
+ * home directory. If found, we return HIDDEN-USER.
+ */
+ if (nflag) {
+ if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ if (lstat(p, &sb) == 0) {
+ free(p);
+ iderror(lport, fport, s, ID_HIDDEN);
+ }
+ free(p);
+ }
+
+ /*
+ * Here, if enabled, we read a user's ".fakeid" file in their
+ * home directory. It consists of a line containing the name
+ * they want.
+ */
+ if (fflag) {
+ int fakeid_fd;
+
+ /*
+ * Here we set ourself to effectively be the user, so we don't
+ * open any files we have no permission to open, especially
+ * symbolic links to sensitive root-owned files or devices.
+ */
+ if (initgroups(pw->pw_name, pw->pw_gid) == -1)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ if (seteuid(pw->pw_uid) == -1)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ /*
+ * We can't stat() here since that would be a race
+ * condition.
+ * Therefore, we open the file we have permissions to open
+ * and if it's not a regular file, we close it and end up
+ * returning the user's real username.
+ */
+ if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
+ iderror(lport, fport, s, ID_UNKNOWN);
+ fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
+ free(p);
+ if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
+ !S_ISREG(sb.st_mode))
+ goto fakeid_fail;
+
+ if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
+ goto fakeid_fail;
+ buf[ssize] = '\0';
+
+ /*
+ * Usually, the file will have the desired identity
+ * in the form "identity\n". Allow for leading white
+ * space and trailing white space/end of line.
+ */
+ p = buf;
+ p += strspn(p, " \t");
+ p[strcspn(p, " \t\r\n")] = '\0';
+ if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
+ p[MAXLOGNAME - 1] = '\0';
+
+ /*
+ * If the name is a zero-length string or matches it
+ * the id or name of another user (unless permitted by -F)
+ * then it is invalid.
+ */
+ if (*p == '\0')
+ goto fakeid_fail;
+ if (!Fflag) {
+ if (iflag) {
+ if (p[strspn(p, "0123456789")] == '\0' &&
+ getpwuid(atoi(p)) != NULL)
+ goto fakeid_fail;
+ } else {
+ if (getpwnam(p) != NULL)
+ goto fakeid_fail;
+ }
+ }
+
+ strlcpy(idbuf, p, sizeof(idbuf));
+
+fakeid_fail:
+ if (fakeid_fd != -1)
+ close(fakeid_fd);
+ }
+
+printit:
+ /* Finally, we make and send the reply. */
+ if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
+ idbuf) == -1) {
+ syslog(LOG_ERR, "asprintf: %m");
+ exit(EX_OSERR);
+ }
+ send(s, p, strlen(p), MSG_EOF);
+ free(p);
+
+ exit(0);
+}
+
+/*
+ * RFC738/868 Time Server.
+ * Return a machine readable date and time, in the form of the
+ * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
+ * returns the number of seconds since midnight, Jan 1, 1970,
+ * we must add 2208988800 seconds to this figure to make up for
+ * some seventy years Bell Labs was asleep.
+ */
+
+uint32_t
+machtime(void)
+{
+
+#define OFFSET ((uint32_t)25567 * 24*60*60)
+ return (htonl((uint32_t)(time(NULL) + OFFSET)));
+#undef OFFSET
+}
+
+/* ARGSUSED */
+void
+machtime_dg(int s, struct servtab *sep)
+{
+ uint32_t result;
+ struct sockaddr_storage ss;
+ socklen_t size;
+
+ size = sizeof(ss);
+ if (recvfrom(s, (char *)&result, sizeof(result), 0,
+ (struct sockaddr *)&ss, &size) < 0)
+ return;
+
+ if (check_loop((struct sockaddr *)&ss, sep))
+ return;
+
+ result = machtime();
+ (void) sendto(s, (char *) &result, sizeof(result), 0,
+ (struct sockaddr *)&ss, size);
+}
+
+/* ARGSUSED */
+void
+machtime_stream(int s, struct servtab *sep __unused)
+{
+ uint32_t result;
+
+ result = machtime();
+ (void) send(s, (char *) &result, sizeof(result), MSG_EOF);
+}
+
+/*
+ * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
+ * services based on the service name sent.
+ *
+ * Based on TCPMUX.C by Mark K. Lottor November 1988
+ * sri-nic::ps:<mkl>tcpmux.c
+ */
+
+#define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
+#define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1)
+
+static int /* # of characters up to \r,\n or \0 */
+getline(int fd, char *buf, int len)
+{
+ int count = 0, n;
+ struct sigaction sa;
+
+ sa.sa_flags = 0;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_handler = SIG_DFL;
+ sigaction(SIGALRM, &sa, (struct sigaction *)0);
+ do {
+ alarm(10);
+ n = read(fd, buf, len-count);
+ alarm(0);
+ if (n == 0)
+ return (count);
+ if (n < 0)
+ return (-1);
+ while (--n >= 0) {
+ if (*buf == '\r' || *buf == '\n' || *buf == '\0')
+ return (count);
+ count++;
+ buf++;
+ }
+ } while (count < len);
+ return (count);
+}
+
+struct servtab *
+tcpmux(int s)
+{
+ struct servtab *sep;
+ char service[MAX_SERV_LEN+1];
+ int len;
+
+ /* Get requested service name */
+ if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
+ strwrite(s, "-Error reading service name\r\n");
+ return (NULL);
+ }
+ service[len] = '\0';
+
+ if (debug)
+ warnx("tcpmux: someone wants %s", service);
+
+ /*
+ * Help is a required command, and lists available services,
+ * one per line.
+ */
+ if (!strcasecmp(service, "help")) {
+ for (sep = servtab; sep; sep = sep->se_next) {
+ if (!ISMUX(sep))
+ continue;
+ (void)write(s,sep->se_service,strlen(sep->se_service));
+ strwrite(s, "\r\n");
+ }
+ return (NULL);
+ }
+
+ /* Try matching a service in inetd.conf with the request */
+ for (sep = servtab; sep; sep = sep->se_next) {
+ if (!ISMUX(sep))
+ continue;
+ if (!strcasecmp(service, sep->se_service)) {
+ if (ISMUXPLUS(sep)) {
+ strwrite(s, "+Go\r\n");
+ }
+ return (sep);
+ }
+ }
+ strwrite(s, "-Service not available\r\n");
+ return (NULL);
+}
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