src/inetd.c - master - niceSOFT/inetutils

src/inetd.c
2 142 строки51 KB
Guillem Jover
inetd: Add new --foreground option
26 янв 2026, 21:48
26 янв 2026, 21:48db70e62
/*
  Copyright (C) 1994-2026 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils 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 3 of the License, or (at
  your option) any later version.

  GNU Inetutils 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, see `http://www.gnu.org/licenses/'. */

/*
 * 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.
 * 3. 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.
 */

/*
 * Inetd - Internet super-server
 *
 * This program invokes all internet services as needed.  Connection-oriented
 * services are invoked each time a connection is made, by creating a process.
 * This process is passed the connection as file descriptor 0 and is expected
 * to do a getpeername to find out the source host and port.
 *
 * Datagram oriented services are invoked when a datagram
 * arrives; a process is created and passed a pending message
 * on file descriptor 0.  Datagram servers may either connect
 * to their peer, freeing up the original socket for inetd
 * to receive further messages on, or ``take over the socket'',
 * processing all arriving datagrams and, eventually, timing
 * out.	 The first type of server is said to be ``multi-threaded'';
 * the second type of server ``single-threaded''.
 *
 * Inetd uses a configuration file which is read at startup
 * and, possibly, at some later time in response to a hangup signal.
 * The configuration file is ``free format'' with fields given in the
 * order shown below.  Continuation lines for an entry must being with
 * a space or tab.  All fields must be present in each entry.
 *
 *	service name			must be in /etc/services or must
 *					name a tcpmux service
 *	socket type			stream/dgram/raw/rdm/seqpacket
 *	protocol			must be in /etc/protocols
 *	wait/nowait[.max]		single-threaded/multi-threaded
 *                                      [with an optional fork limit]
 *	user[:group] or user[.group]	user (and group) to run daemon as
 *	server program			full path name
 *	server program arguments	arguments starting with argv[0]
 *
 * TCP services without official port numbers are handled with the
 * RFC1078-based tcpmux internal service. Tcpmux listens on port 1 for
 * requests. When a connection is made from a foreign host, the service
 * requested is passed to tcpmux, which looks it up in the servtab list
 * and returns the proper entry for the service. Tcpmux returns a
 * negative reply if the service doesn't exist, otherwise the invoked
 * server is expected to return the positive reply if the service type in
 * inetd.conf file has the prefix "tcpmux/". If the service type has the
 * prefix "tcpmux/+", tcpmux will return the positive reply for the
 * process; this is for compatibility with older server code, and also
 * allows you to invoke programs that use stdin/stdout without putting any
 * special server code in them. Services that use tcpmux are "nowait"
 * because they do not have a well-known port and hence cannot listen
 * for new requests.
 *
 * Comment lines are indicated by a `#' in column 1.
 */

#include <config.h>

#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <time.h>
#ifdef HAVE_SYS_RESOURCE_H
# include <sys/resource.h>
#endif

#include <netinet/in.h>
#include <arpa/inet.h>

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <argp.h>
#include <argp-version-etc.h>
#include <progname.h>
#include <sys/select.h>
#include <grp.h>

#include "libinetutils.h"
#include "argcv.h"
#include "version-etc.h"
#include "attribute.h"

#ifndef EAI_ADDRFAMILY
# define EAI_ADDRFAMILY 1
#endif

#define TOOMANY		1000	/* don't start more than TOOMANY */
#define CNT_INTVL	60	/* servers in CNT_INTVL sec. */
#define RETRYTIME	(60*10)	/* retry after bind or server fail */

#ifndef SIGCHLD
# define SIGCHLD	SIGCLD
#endif

#ifndef HAVE_SIGACTION
# define SIGBLOCK	(sigmask(SIGCHLD)|sigmask(SIGHUP)|sigmask(SIGALRM))
#endif

bool debug = false;
bool foreground = false;
int nsock, maxsock;
fd_set allsock;
int options;
int timingout;
unsigned toomany = TOOMANY;
char **Argv;
char *LastArg;

char **config_files;

static bool env_option = false;	/* Set environment variables */
static bool resolve_option = false;	/* Resolve IP addresses */
static bool pidfile_option = true;	/* Record the PID in a file */
static const char *pid_file = PATH_INETDPID;

const char args_doc[] = "[CONF-FILE [CONF-DIR]]...";
const char doc[] = "Internet super-server.";

/* Define keys for long options that do not have short counterparts. */
enum
{
  OPT_ENVIRON = 256,
  OPT_FOREGROUND,
  OPT_RESOLVE
};

const char *program_authors[] = {
  "Alain Magloire", "Alfred M. Szmidt", "Debarshi Ray",
  "Jakob 'sparky' Kaivo", "Jeff Bailey",
  "Jeroen Dekkers", "Marcus Brinkmann", "Sergey Poznyakoff",
  "others", NULL
};

static struct argp_option argp_options[] = {
#define GRP 0
  {"foreground", OPT_FOREGROUND, NULL, 0,
   "run in foreground mode", GRP + 1},
  {"debug", 'd', NULL, 0,
   "turn on debugging, run in foreground mode", GRP + 1},
  {"environment", OPT_ENVIRON, NULL, 0,
   "pass local and remote socket information in environment variables",
   GRP + 1},
  {"pidfile", 'p', "PIDFILE", OPTION_ARG_OPTIONAL,
   "override pidfile (default: \"" PATH_INETDPID "\")",
   GRP + 1},
  {"rate", 'R', "NUMBER", 0,
   "maximum invocation rate (per minute)", GRP + 1},
  {"resolve", OPT_RESOLVE, NULL, 0,
   "resolve IP addresses when setting environment variables "
   "(see --environment)", GRP + 1},
#undef GRP
  {NULL, 0, NULL, 0, NULL, 0}
};

static error_t
parse_opt (int key, char *arg, struct argp_state *state MAYBE_UNUSED)
{
  char *p;
  int number;

  switch (key)
    {
    case 'd':
      debug = true;
      foreground = true;
      options |= SO_DEBUG;
      break;

    case OPT_FOREGROUND:
      foreground = true;
      break;

    case OPT_ENVIRON:
      env_option = true;
      break;

    case 'p':
      if (arg && strlen (arg))
	pid_file = arg;
      else
	pidfile_option = false;
      break;

    case 'R':
      number = strtol (arg, &p, 0);
      if (number < 1 || *p)
	syslog (LOG_ERR, "-R %s: bad value for service invocation rate", arg);
      else
	toomany = number;
      break;

    case OPT_RESOLVE:
      resolve_option = true;
      break;

    default:
      return ARGP_ERR_UNKNOWN;
    }

  return 0;
}

static struct argp argp =
  { argp_options, parse_opt, args_doc, doc, NULL, NULL, NULL };


struct servtab
{
  const char *se_file;
  int se_line;
  char *se_node;		/* node name */
  char *se_service;		/* name of service */
  int se_socktype;		/* type of socket to use */
  char *se_proto;		/* protocol used */
  pid_t se_wait;		/* single threaded server */
  unsigned se_max;		/* Maximum number of instances per CNT_INTVL */
  short se_checked;		/* looked at during merge */
  char *se_user;		/* user name to run as */
  char *se_group;		/* group name to run as */
  struct biltin *se_bi;		/* if built-in, description */
  char *se_server;		/* server program */
  char **se_argv;		/* program arguments */
  size_t se_argc;		/* number of arguments */
  int se_fd;			/* open descriptor */
  int se_type;			/* type */
  sa_family_t se_family;	/* address family of the socket */
  char se_v4mapped;		/* 1 = accept v4mapped connection, 0 = don't */
  struct sockaddr_storage se_ctrladdr;	/* bound address */
  socklen_t se_addrlen;		/* exact address length in use */
  unsigned se_refcnt;
  unsigned se_count;		/* number started since se_time */
  struct timeval se_time;	/* start of se_count */
  struct servtab *se_next;
} *servtab;

#define NORM_TYPE	0
#define MUX_TYPE	1
#define MUXPLUS_TYPE	2
#define ISMUX(sep)	(((sep)->se_type == MUX_TYPE) ||	\
			 ((sep)->se_type == MUXPLUS_TYPE))
#define ISMUXPLUS(sep)	((sep)->se_type == MUXPLUS_TYPE)


/* Built-in services */
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 *);
void machtime_dg (int, struct servtab *);
void machtime_stream (int, struct servtab *);
void tcpmux (int s, struct servtab *sep);

struct biltin
{
  const char *bi_service;	/* internally provided service name */
  int bi_socktype;		/* type of socket supported */
  short bi_fork;		/* 1 if should fork before call */
  short bi_wait;		/* 1 if should wait for child */
  void (*bi_fn) (int s, struct servtab *);	/*function which performs it */
} biltins[] = {
  /* Echo received data */
  {"echo", SOCK_STREAM, 1, 0, echo_stream},
  {"echo", SOCK_DGRAM, 0, 0, echo_dg},
  /* Internet /dev/null */
  {"discard", SOCK_STREAM, 1, 0, discard_stream},
  {"discard", SOCK_DGRAM, 0, 0, discard_dg},
  /* Return 32 bit time since 1900 */
  {"time", SOCK_STREAM, 0, 0, machtime_stream},
  {"time", SOCK_DGRAM, 0, 0, machtime_dg},
  /* Return human-readable time */
  {"daytime", SOCK_STREAM, 0, 0, daytime_stream},
  {"daytime", SOCK_DGRAM, 0, 0, daytime_dg},
  /* Familiar character generator */
  {"chargen", SOCK_STREAM, 1, 0, chargen_stream},
  {"chargen", SOCK_DGRAM, 0, 0, chargen_dg},
  {"tcpmux", SOCK_STREAM, 1, 0, tcpmux},
  {NULL, 0, 0, 0, NULL}
};

struct biltin *
bi_lookup (const struct servtab *sep)
{
  struct biltin *bi;

  for (bi = biltins; bi->bi_service; bi++)
    if (bi->bi_socktype == sep->se_socktype
	&& strcmp (bi->bi_service, sep->se_service) == 0)
      return bi;
  return NULL;
}


/* Signal handling */

#if defined HAVE_SIGACTION
# define SIGSTATUS sigset_t
# define sigstatus_empty(s) sigemptyset(&s)
# define inetd_pause(s) sigsuspend(&s)
#else
# define SIGSTATUS long
# define sigstatus_empty(s) s = 0
# define inetd_pause(s) sigpause (s)
#endif

void
signal_set_handler (int signo, void (*handler) (int))
{
#if defined HAVE_SIGACTION
  struct sigaction sa;
  memset ((char *) &sa, 0, sizeof (sa));
  sigemptyset (&sa.sa_mask);
  sigaddset (&sa.sa_mask, signo);
# ifdef SA_RESTART
  sa.sa_flags = SA_RESTART;
# endif
  sa.sa_handler = handler;
  sigaction (signo, &sa, NULL);
#elif defined(HAVE_SIGVEC)
  struct sigvec sv;
  memset (&sv, 0, sizeof (sv));
  sv.sv_mask = SIGBLOCK;
  sv.sv_handler = handler;
  sigvec (signo, &sv, NULL);
#else /* !HAVE_SIGVEC */
  signal (signo, handler);
#endif /* HAVE_SIGACTION */
}

void
signal_block (SIGSTATUS *old_status)
{
#ifdef HAVE_SIGACTION
  sigset_t sigs;

  sigemptyset (&sigs);
  sigaddset (&sigs, SIGCHLD);
  sigaddset (&sigs, SIGHUP);
  sigaddset (&sigs, SIGALRM);
  sigprocmask (SIG_BLOCK, &sigs, old_status);
#else
  long omask = sigblock (SIGBLOCK);
  if (old_status)
    *old_status = omask;
#endif
}

void
signal_unblock (SIGSTATUS *status)
{
#ifdef HAVE_SIGACTION
  if (status)
    sigprocmask (SIG_SETMASK, status, 0);
  else
    {
      sigset_t empty;
      sigemptyset (&empty);
      sigprocmask (SIG_SETMASK, &empty, 0);
    }
#else
  sigsetmask (status ? *status : 0);
#endif
}

void
run_service (int ctrl, struct servtab *sep)
{
  struct passwd *pwd;
  struct group *grp = NULL;
  char buf[50];

  if (sep->se_bi)
    {
      (*sep->se_bi->bi_fn) (ctrl, sep);
    }
  else
    {
      if (debug)
	fprintf (stderr, "%d execl %s\n", (int) getpid (), sep->se_server);
      dup2 (ctrl, 0);
      close (ctrl);
      dup2 (0, 1);
      dup2 (0, 2);
      pwd = getpwnam (sep->se_user);
      if (pwd == NULL)
	{
	  syslog (LOG_ERR, "%s/%s: %s: No such user",
		  sep->se_service, sep->se_proto, sep->se_user);
	  if (sep->se_socktype != SOCK_STREAM)
	    recv (0, buf, sizeof buf, 0);
	  _exit (EXIT_FAILURE);
	}
      if (sep->se_group && *sep->se_group)
	{
	  grp = getgrnam (sep->se_group);
	  if (grp == NULL)
	    {
	      syslog (LOG_ERR, "%s/%s: %s: No such group",
		      sep->se_service, sep->se_proto, sep->se_group);
	      if (sep->se_socktype != SOCK_STREAM)
		recv (0, buf, sizeof buf, 0);
	      _exit (EXIT_FAILURE);
	    }
	}
      if (pwd->pw_uid)
	{
	  if (grp && grp->gr_gid)
	    {
	      if (setgid (grp->gr_gid) < 0)
		{
		  syslog (LOG_ERR, "%s: can't set gid %d: %m",
			  sep->se_service, grp->gr_gid);
		  _exit (EXIT_FAILURE);
		}
	    }
	  else if (setgid (pwd->pw_gid) < 0)
	    {
	      syslog (LOG_ERR, "%s: can't set gid %d: %m",
		      sep->se_service, pwd->pw_gid);
	      _exit (EXIT_FAILURE);
	    }
#ifdef HAVE_INITGROUPS
	  initgroups (pwd->pw_name,
		      (grp && grp->gr_gid) ? grp->gr_gid : pwd->pw_gid);
#endif
	  if (setuid (pwd->pw_uid) < 0)
	    {
	      syslog (LOG_ERR, "%s: can't set uid %d: %m",
		      sep->se_service, pwd->pw_uid);
	      _exit (EXIT_FAILURE);
	    }
	}
      execv (sep->se_server, sep->se_argv);
      if (sep->se_socktype != SOCK_STREAM)
	recv (0, buf, sizeof buf, 0);
      syslog (LOG_ERR, "cannot execute %s: %m", sep->se_server);
      _exit (EXIT_FAILURE);
    }
}

void
reapchild (int signo MAYBE_UNUSED)
{
  int status;
  pid_t pid;
  struct servtab *sep;

  for (;;)
    {
#ifdef HAVE_WAIT3
      pid = wait3 (&status, WNOHANG, NULL);
#else
      pid = wait (&status);
#endif
      if (pid <= 0)
	break;
      if (debug)
	fprintf (stderr, "%d reaped, status %#x\n", (int) pid, status);
      for (sep = servtab; sep; sep = sep->se_next)
	if (sep->se_wait == pid)
	  {
	    if (status)
	      syslog (LOG_WARNING, "%s: exit status 0x%x",
		      sep->se_server, status);
	    if (debug)
	      fprintf (stderr, "restored %s, fd %d\n",
		       sep->se_service, sep->se_fd);
	    FD_SET (sep->se_fd, &allsock);
	    nsock++;
	    sep->se_wait = 1;
	  }
    }
}



char *
newstr (const char *cp)
{
  char *s;
  s = strdup (cp ? cp : "");
  if (s != NULL)
    return s;
  syslog (LOG_ERR, "strdup: %m");
  exit (-1);
}

void
dupmem (void **pptr, size_t size)
{
  void *ptr = malloc (size);
  if (!ptr)
    {
      syslog (LOG_ERR, "dupmem: %m");
      exit (-1);
    }
  memcpy (ptr, *pptr, size);
  *pptr = ptr;
}

void
dupstr (char **pstr)
{
  if (*pstr)
    dupmem ((void **) pstr, strlen (*pstr) + 1);
}


/*
 * print_service:
 *	Dump relevant information to stderr
 */
void
print_service (const char *action, struct servtab *sep)
{
  fprintf (stderr,
	   "%s:%d: %s: %s:%s proto=%s, wait=%d, max=%u, "
	   "user=%s group=%s builtin=%s server=%s\n",
	   sep->se_file, sep->se_line,
	   action,
	   ISMUX (sep) ? (ISMUXPLUS (sep) ? "tcpmuxplus" : "tcpmux")
	   : (sep->se_node ? sep->se_node : "*"),
	   sep->se_service, sep->se_proto,
	   (int) sep->se_wait, sep->se_max,
	   sep->se_user, sep->se_group,
	   sep->se_bi ? sep->se_bi->bi_service : "no", sep->se_server);
}


/* Configuration */
int
setup (struct servtab *sep)
{
  int err;
  int on = 1;

tryagain:
  sep->se_fd = socket (sep->se_family, sep->se_socktype, 0);
  if (sep->se_fd < 0)
    {
      /* If we don't support creating AF_INET6 sockets, create AF_INET
         sockets.  */
      if (errno == EAFNOSUPPORT && sep->se_family == AF_INET6
	  && sep->se_v4mapped)
	{
	  /* Fall back to IPv4 silently.  */
	  sep->se_family = AF_INET;
	  goto tryagain;
	}

      if (debug)
	fprintf (stderr, "socket failed on %s/%s: %s\n",
		 sep->se_service, sep->se_proto, strerror (errno));
      syslog (LOG_ERR, "%s/%s: socket: %m", sep->se_service, sep->se_proto);
      return 1;
    }
#ifdef IPV6
  if (sep->se_family == AF_INET6)
    {
      /* Reverse the value of SEP->se_v4mapped, since otherwise if
         using `tcp6' as a protocol type, all connections will be
         mapped to IPv6, and with `tcp6only', IPv4 gets mapped to
         IPv6.  */
      int val = sep->se_v4mapped ? 0 : 1;
      if (setsockopt (sep->se_fd, IPPROTO_IPV6, IPV6_V6ONLY,
		      (char *) &val, sizeof (val)) < 0)
	syslog (LOG_ERR, "setsockopt (IPV6_V6ONLY): %m");
    }
#endif
  if (strncmp (sep->se_proto, "tcp", 3) == 0 && (options & SO_DEBUG))
    {
      if (setsockopt (sep->se_fd, SOL_SOCKET, SO_DEBUG, (char *) &on, sizeof (on)) < 0 && errno != EACCES)	/* Ignore insufficient permission.  */
	syslog (LOG_ERR, "setsockopt (SO_DEBUG): %m");
    }

  err = setsockopt (sep->se_fd, SOL_SOCKET, SO_REUSEADDR,
		    (char *) &on, sizeof (on));
  if (err < 0)
    syslog (LOG_ERR, "setsockopt (SO_REUSEADDR): %m");

  err = bind (sep->se_fd, (struct sockaddr *) &sep->se_ctrladdr,
	      sep->se_addrlen);
  if (err < 0)
    {
      /* If we can't bind with AF_INET6 try again with AF_INET.  */
      if ((errno == EADDRNOTAVAIL || errno == EAFNOSUPPORT)
	  && sep->se_family == AF_INET6 && sep->se_v4mapped)
	{
	  /* Fall back to IPv4 silently.  */
	  sep->se_family = AF_INET;
	  close (sep->se_fd);
	  goto tryagain;
	}
      if (sep->se_node)
	{
	  if (debug)
	    fprintf (stderr, "bind failed for %s %s/%s: %s\n",
		     sep->se_node, sep->se_service, sep->se_proto,
		     strerror (errno));
	  syslog (LOG_ERR, "%s %s/%s: bind: %m",
		  sep->se_node, sep->se_service, sep->se_proto);
	}
      else
	{
	  if (debug)
	    fprintf (stderr, "bind failed for %s/%s: %s\n",
		     sep->se_service, sep->se_proto, strerror (errno));
	  syslog (LOG_ERR, "%s/%s: bind: %m", sep->se_service, sep->se_proto);
	}
      close (sep->se_fd);
      sep->se_fd = -1;
      if (!timingout)
	{
	  timingout = 1;
	  alarm (RETRYTIME);
	}
      return 1;
    }
  return 0;
}

void
servent_setup (struct servtab *sep)
{
  sep->se_checked = 1;
  if (sep->se_fd == -1 && setup (sep) == 0)
    {
      if (sep->se_socktype == SOCK_STREAM)
	listen (sep->se_fd, 10);
      FD_SET (sep->se_fd, &allsock);
      nsock++;
      if (sep->se_fd > maxsock)
	maxsock = sep->se_fd;
      if (debug)
	fprintf (stderr, "registered %s on %d\n", sep->se_server, sep->se_fd);
    }
}

void
retry (int signo MAYBE_UNUSED)
{
  struct servtab *sep;

  timingout = 0;
  for (sep = servtab; sep; sep = sep->se_next)
    if (sep->se_fd == -1 && !ISMUX (sep))
      setup (sep);
}

/*
 * Finish with a service and its socket.
 */
void
close_sep (struct servtab *sep)
{
  if (sep->se_fd >= 0)
    {
      nsock--;
      FD_CLR (sep->se_fd, &allsock);
      close (sep->se_fd);
      sep->se_fd = -1;
    }
  sep->se_count = 0;
  /*
   * Don't keep the pid of this running daemon: when reapchild()
   * reaps this pid, it would erroneously increment nsock.
   */
  if (sep->se_wait > 1)
    sep->se_wait = 1;
}

struct servtab *
enter (struct servtab *cp)
{
  struct servtab *sep;
  SIGSTATUS sigstatus;
  size_t i;

  /* Checking/Removing duplicates */
  for (sep = servtab; sep; sep = sep->se_next)
    if (memcmp (&sep->se_ctrladdr, &cp->se_ctrladdr,
		sizeof (sep->se_ctrladdr)) == 0
	&& strcmp (sep->se_service, cp->se_service) == 0
	&& strcmp (sep->se_proto, cp->se_proto) == 0
	&& ISMUX (sep) == ISMUX (cp))
      break;
  if (sep != 0)
    {
      signal_block (&sigstatus);
      /*
       * sep->se_wait may be holding the pid of a daemon
       * that we're waiting for.  If so, don't overwrite
       * it unless the config file explicitly says don't
       * wait.
       */
      if (cp->se_bi == 0 && (sep->se_wait == 1 || cp->se_wait == 0))
	sep->se_wait = cp->se_wait;
#define SWAP(a, b) { char *c = a; a = b; b = c; }
      if (cp->se_user)
	SWAP (sep->se_user, cp->se_user);
      if (cp->se_group)
	SWAP (sep->se_group, cp->se_group);
      if (cp->se_server)
	SWAP (sep->se_server, cp->se_server);
      argcv_free (sep->se_argc, sep->se_argv);
      sep->se_argc = cp->se_argc;
      sep->se_argv = cp->se_argv;
      cp->se_argc = 0;
      cp->se_argv = NULL;
      sep->se_checked = 1;
      signal_unblock (&sigstatus);
      if (debug)
	print_service ("REDO", sep);
      return sep;
    }

  if (debug)
    print_service ("ADD ", cp);

  sep = (struct servtab *) malloc (sizeof (*sep));
  if (sep == NULL)
    {
      syslog (LOG_ERR, "Out of memory.");
      exit (-1);
    }
  *sep = *cp;
  dupstr (&sep->se_node);
  dupstr (&sep->se_service);
  dupstr (&sep->se_proto);
  dupstr (&sep->se_user);
  dupstr (&sep->se_group);
  dupstr (&sep->se_server);
  dupmem ((void **) &sep->se_argv, sep->se_argc * sizeof (sep->se_argv[0]));
  for (i = 0; i < sep->se_argc; i++)
    dupstr (&sep->se_argv[i]);

  sep->se_fd = -1;
  signal_block (&sigstatus);
  sep->se_next = servtab;
  servtab = sep;
  signal_unblock (&sigstatus);
  return sep;
}

#define IPV4_NUMCHARS ".0123456789"
#define IPV6_NUMCHARS ".:0123456789abcdefABCDEF"

int
inetd_getaddrinfo (struct servtab *sep, int proto, struct addrinfo **result)
{
  struct addrinfo hints;
#ifdef IPV6
  bool numeric_address = false;

  /* In case a numerical address is supplied, which does not
     apply to the indicated domain, a non-local resolver
     will wait in vain until time out occurs, thus blocking.
     Avoid this by falling back to numerical host resolving
     when address string seems to be numerical.  */

  /* Purely numeric address?  Separate criteria for IPv4 and IPv6,
     since IPv6 allows hexadecimal coding and IPv4 mapping!  */
  if (sep->se_node
      && (strspn (sep->se_node, IPV4_NUMCHARS) == strlen (sep->se_node)
	  || (strchr (sep->se_node, ':')
	      && strspn (sep->se_node, IPV6_NUMCHARS))))
    numeric_address = true;
  else if (debug && sep->se_node)
    fprintf (stderr, "Resolving address: %s\n", sep->se_node);
#endif /* IPV6 */

  memset (&hints, 0, sizeof (hints));

  hints.ai_flags = AI_PASSIVE;
#ifdef AI_V4MAPPED
  if (sep->se_v4mapped && (sep->se_family != AF_INET))
    hints.ai_flags |= AI_V4MAPPED;
#endif
#ifdef IPV6
  if (numeric_address)
    hints.ai_flags |= AI_NUMERICHOST;
#endif
  hints.ai_family = sep->se_family;
  hints.ai_socktype = sep->se_socktype;
  hints.ai_protocol = proto;

  return getaddrinfo (sep->se_node, sep->se_service, &hints, result);
}

int
expand_enter (struct servtab *sep)
{
  int err;
  struct addrinfo *result, *rp;
  struct protoent *proto;
  struct servtab *cp;

  /* Make sure that tcp6 etc also work.  */
  if (strncmp (sep->se_proto, "tcp", 3) == 0)
    proto = getprotobyname ("tcp");
  else if (strncmp (sep->se_proto, "udp", 3) == 0)
    proto = getprotobyname ("udp");
  else
    proto = getprotobyname (sep->se_proto);

  if (!proto)
    {
      syslog (LOG_ERR, "%s: Unknown protocol", sep->se_proto);
      return 1;
    }

  err = inetd_getaddrinfo (sep, proto->p_proto, &result);
#if IPV6
  if (err == EAI_ADDRFAMILY && sep->se_family == AF_INET6 && sep->se_v4mapped)
    {
      /* Fall back to IPv4 silently.  */
      sep->se_family = AF_INET;
      err = inetd_getaddrinfo (sep, proto->p_proto, &result);
    }
#endif
  if (err)
    {
      const char *errmsg;

      if (err == EAI_SYSTEM)
	errmsg = strerror (errno);
      else
	errmsg = gai_strerror (err);

      if (sep->se_node)
	{
	  if (debug)
	    fprintf (stderr, "resolution of %s %s/%s failed: %s\n",
		     sep->se_node, sep->se_service, sep->se_proto, errmsg);
	  syslog (LOG_ERR, "%s %s/%s: getaddrinfo: %s",
		  sep->se_node, sep->se_service, sep->se_proto, errmsg);
	}
      else
	{
	  if (debug)
	    fprintf (stderr, "resolution of %s/%s failed: %s\n",
		     sep->se_service, sep->se_proto, errmsg);
	  syslog (LOG_ERR, "%s/%s: getaddrinfo: %s",
		  sep->se_service, sep->se_proto, errmsg);
	}
      return 1;
    }

  for (rp = result; rp != NULL; rp = rp->ai_next)
    {
      memset (&sep->se_ctrladdr, 0, sizeof (sep->se_ctrladdr));
      memcpy (&sep->se_ctrladdr, rp->ai_addr, rp->ai_addrlen);
      sep->se_addrlen = rp->ai_addrlen;
      cp = enter (sep);
      servent_setup (cp);
    }

  freeaddrinfo (result);

  return 0;
}


/* Configuration parser */
char *global_serv_node;
char *serv_node;
size_t serv_node_offset;

char *linebuf = NULL;
size_t linebufsize = 0;

FILE *
setconfig (const char *file)
{
  return fopen (file, "r");
}

void
endconfig (FILE *fconfig)
{
  if (fconfig)
    fclose (fconfig);
}

void
freeconfig (struct servtab *cp)
{
  free (cp->se_node);
  free (cp->se_service);
  free (cp->se_proto);
  free (cp->se_user);
  free (cp->se_group);
  free (cp->se_server);
  argcv_free (cp->se_argc, cp->se_argv);
}

#define INETD_SERVICE      0	/* service name */
#define INETD_SOCKET       1	/* socket type */
#define INETD_PROTOCOL     2	/* protocol */
#define INETD_WAIT         3	/* wait/nowait */
#define INETD_USER         4	/* user */
#define INETD_SERVER_PATH  5	/* server program path */
#define INETD_SERVER_ARGS  6	/* server program arguments */

#define INETD_FIELDS_MIN   6	/* Minimum number of fields in entry */

struct servtab *
next_node_sep (struct servtab *sep)
{
  if (serv_node)
    {
      size_t i = strcspn (serv_node + serv_node_offset, ",");
      sep->se_node = malloc (i + 1);
      if (!sep->se_node)
	{
	  syslog (LOG_ERR, "malloc: %m");
	  exit (-1);
	}
      memcpy (sep->se_node, serv_node + serv_node_offset, i);
      sep->se_node[i] = 0;
      serv_node_offset += i;
      if (serv_node[serv_node_offset])
	serv_node_offset++;
      else
	{
	  free (serv_node);
	  serv_node = NULL;
	}
    }
  return sep;
}

struct servtab *
getconfigent (FILE *fconfig, const char *file, size_t *line)
{
  static struct servtab serv;
  struct servtab *sep = &serv;
  int argc = 0;
  size_t i;
  char **argv = NULL;
  char *node, *service;
  static char TCPMUX_TOKEN[] = "tcpmux/";
#define MUX_LEN		(sizeof(TCPMUX_TOKEN)-1)

  if (serv_node)
    return next_node_sep (sep);

  memset (sep, 0, sizeof *sep);

  while (1)
    {
      argcv_free (argc, argv);
      freeconfig (sep);
      memset (sep, 0, sizeof *sep);

      do
	{
	  ssize_t n = getline (&linebuf, &linebufsize, fconfig);
	  if (n < 0)
	    return 0;
	  else if (n == 0)
	    continue;

	  if (linebuf[n - 1] == '\n')
	    linebuf[n - 1] = 0;
	  ++*line;
	}
      while (*linebuf == '#' || *linebuf == 0);

      if (argcv_get (linebuf, "", &argc, &argv))
	continue;

      if (argc < INETD_FIELDS_MIN)
	{
	  if (argc == 1 && argv[0][strlen (argv[0]) - 1] == ':')
	    {
	      argv[0][strlen (argv[0]) - 1] = 0;
	      free (global_serv_node);
	      if (strcmp (argv[0], "*"))
		global_serv_node = newstr (argv[0]);
	    }
	  else
	    syslog (LOG_ERR, "%s:%lu: not enough fields",
		    file, (unsigned long) *line);
	  continue;
	}

      sep->se_file = file;
      sep->se_line = *line;

      node = argv[INETD_SERVICE];
      service = strrchr (node, ':');
      if (!service)
	{
	  if (global_serv_node)
	    {
	      node = global_serv_node;
	      serv_node = newstr (node);
	      serv_node_offset = 0;
	    }
	  else
	    node = NULL;

	  service = argv[INETD_SERVICE];
	}
      else
	{
	  *service++ = 0;
	  if (strcmp (node, "*") == 0)
	    node = NULL;
	  else
	    {
	      serv_node = newstr (node);
	      serv_node_offset = 0;
	    }
	}

      if (strncmp (service, TCPMUX_TOKEN, MUX_LEN) == 0)
	{
	  char *c = service + MUX_LEN;
	  if (*c == '+')
	    {
	      sep->se_type = MUXPLUS_TYPE;
	      c++;
	    }
	  else
	    sep->se_type = MUX_TYPE;
	  sep->se_service = newstr (c);
	}
      else
	{
	  sep->se_service = newstr (service);
	  sep->se_type = NORM_TYPE;
	}

      if (strcmp (argv[INETD_SOCKET], "stream") == 0)
	sep->se_socktype = SOCK_STREAM;
      else if (strcmp (argv[INETD_SOCKET], "dgram") == 0)
	sep->se_socktype = SOCK_DGRAM;
      else if (strcmp (argv[INETD_SOCKET], "rdm") == 0)
	sep->se_socktype = SOCK_RDM;
      else if (strcmp (argv[INETD_SOCKET], "seqpacket") == 0)
	sep->se_socktype = SOCK_SEQPACKET;
      else if (strcmp (argv[INETD_SOCKET], "raw") == 0)
	sep->se_socktype = SOCK_RAW;
      else
	{
	  syslog (LOG_WARNING, "%s:%lu: bad socket type",
		  file, (unsigned long) *line);
	  sep->se_socktype = -1;
	}

      sep->se_proto = newstr (argv[INETD_PROTOCOL]);

#ifdef IPV6
      /* We default to IPv4. */
      sep->se_family = AF_INET;
      sep->se_v4mapped = 1;

      if ((strncmp (sep->se_proto, "tcp", 3) == 0)
	  || (strncmp (sep->se_proto, "udp", 3) == 0))
	{
	  if (sep->se_proto[3] == '6')
	    {
	      sep->se_family = AF_INET6;
	      sep->se_v4mapped = 0;
	      /* Check for tcp6only and udp6only.  */
	      if (strcmp (&sep->se_proto[3], "6only") == 0)
		sep->se_v4mapped = 0;
	    }
	  else if (sep->se_proto[3] == '4')
	    {
	      sep->se_family = AF_INET;
	    }
	}
#else
      if ((strncmp (sep->se_proto, "tcp6", 4) == 0)
	  || (strncmp (sep->se_proto, "udp6", 4) == 0))
	{
	  syslog (LOG_ERR, "%s:%lu: %s: IPv6 support isn't enabled",
		  file, (unsigned long) *line, sep->se_proto);
	  continue;
	}

      sep->se_family = AF_INET;
#endif
      {
	char *p, *q;

	p = strchr (argv[INETD_WAIT], '.');
	if (p)
	  *p++ = 0;
	if (strcmp (argv[INETD_WAIT], "wait") == 0)
	  sep->se_wait = 1;
	else if (strcmp (argv[INETD_WAIT], "nowait") == 0)
	  sep->se_wait = 0;
	else
	  {
	    syslog (LOG_WARNING, "%s:%lu: bad wait type",
		    file, (unsigned long) *line);
	  }
	if (p)
	  {
	    sep->se_max = strtoul (p, &q, 10);
	    if (*q)
	      syslog (LOG_WARNING, "%s:%lu: invalid number (%s)",
		      file, (unsigned long) *line, p);
	  }
      }

      if (ISMUX (sep))
	{
	  /*
	   * Silently enforce "nowait" for TCPMUX services since
	   * they don't have an assigned port to listen on.
	   */
	  sep->se_wait = 0;

	  if (strncmp (sep->se_proto, "tcp", 3))
	    {
	      syslog (LOG_ERR, "%s:%lu: bad protocol for tcpmux service %s",
		      file, (unsigned long) *line, sep->se_service);
	      continue;
	    }
	  if (sep->se_socktype != SOCK_STREAM)
	    {
	      syslog (LOG_ERR,
		      "%s:%lu: bad socket type for tcpmux service %s",
		      file, (unsigned long) *line, sep->se_service);
	      continue;
	    }
	}

      /* Establish optional group identity:
       *   user:group, user.group
       */
      {
	char *p;

	sep->se_user = newstr (argv[INETD_USER]);

	p = strchr (sep->se_user, ':');
	if (!p)
	  p = strchr (sep->se_user, '.');

	if (p)
	  {
	    *p = '\0';
	    sep->se_group = newstr (++p);
	  }
	else
	  sep->se_group = newstr (NULL);
      }

      sep->se_server = newstr (argv[INETD_SERVER_PATH]);
      if (strcmp (sep->se_server, "internal") == 0)
	{
	  sep->se_bi = bi_lookup (sep);
	  if (!sep->se_bi)
	    {
	      syslog (LOG_ERR, "%s:%lu: internal service %s unknown",
		      file, (unsigned long) *line, sep->se_service);
	      continue;
	    }
	  sep->se_wait = sep->se_bi->bi_wait;
	}
      else
	sep->se_bi = NULL;

      sep->se_argc = argc - INETD_FIELDS_MIN + 1;
      sep->se_argv = calloc (sep->se_argc + 1, sizeof sep->se_argv[0]);
      if (!sep->se_argv)
	{
	  syslog (LOG_ERR, "%s:%lu: Out of memory.",
		  file, (unsigned long) *line);
	  exit (-1);
	}

      for (i = 0; i < sep->se_argc; i++)
	{
	  sep->se_argv[i] = argv[INETD_SERVER_ARGS + i];
	  argv[INETD_SERVER_ARGS + i] = 0;
	}

      /* If no arguments are provided, use server name as argv[0].  */
      if (sep->se_argc == 1)
	{
	  const char *argv0 = strrchr (sep->se_server, '/');
	  if (argv0)
	    argv0++;
	  else
	    argv0 = sep->se_server;
	  sep->se_argv[0] = newstr (argv0);
	}

      sep->se_argv[i] = NULL;
      break;
    }
  argcv_free (argc, argv);
  return next_node_sep (sep);
}

void
nextconfig (const char *file)
{
#ifndef IPV6
  struct servent *sp;
#endif
  struct servtab *sep, **sepp;
  struct passwd *pwd;
  struct group *grp;
  FILE *fconfig;
  SIGSTATUS sigstatus;

  size_t line = 0;

  fconfig = setconfig (file);
  if (!fconfig)
    {
      syslog (LOG_ERR, "%s: %m", file);
      return;
    }
  while ((sep = getconfigent (fconfig, file, &line)))
    {
      pwd = getpwnam (sep->se_user);
      if (pwd == NULL)
	{
	  syslog (LOG_ERR, "%s/%s: No such user '%s', service ignored",
		  sep->se_service, sep->se_proto, sep->se_user);
	  continue;
	}
      if (sep->se_group && *sep->se_group)
	{
	  grp = getgrnam (sep->se_group);
	  if (grp == NULL)
	    {
	      syslog (LOG_ERR, "%s/%s: No such group '%s', service ignored",
		      sep->se_service, sep->se_proto, sep->se_group);
	      continue;
	    }
	}
      if (ISMUX (sep))
	{
	  sep->se_fd = -1;
	  sep->se_checked = 1;
	  enter (sep);
	}
      else
	expand_enter (sep);

      if (serv_node)
	free (sep->se_node);
      else
	freeconfig (sep);
    }
  endconfig (fconfig);
  /*
   * Purge anything not looked at above.
   */
  signal_block (&sigstatus);
  sepp = &servtab;
  while ((sep = *sepp))
    {
      if (sep->se_checked)
	{
	  sepp = &sep->se_next;
	  continue;
	}
      *sepp = sep->se_next;
      if (sep->se_fd >= 0)
	close_sep (sep);
      if (debug)
	print_service ("FREE", sep);
      freeconfig (sep);
      free (sep);
    }
  signal_unblock (&sigstatus);
}

void
fix_tcpmux (void)
{
  struct servtab *sep;
  int need_tcpmux = 0;
  int has_tcpmux = 0;

  for (sep = servtab; sep; sep = sep->se_next)
    {
      if (sep->se_checked)
	{
	  if (ISMUX (sep))
	    {
	      if (has_tcpmux)
		return;
	      need_tcpmux = 1;
	    }
	  if (strcmp (sep->se_service, "tcpmux") == 0)
	    {
	      if (need_tcpmux)
		return;
	      has_tcpmux = 1;
	    }
	}
    }
  if (need_tcpmux && !has_tcpmux)
    {
      struct servtab serv;
      memset (&serv, 0, sizeof (serv));

      serv.se_file = "fix_tcpmux";
      serv.se_service = newstr ("tcpmux");
      serv.se_socktype = SOCK_STREAM;
      serv.se_checked = 1;
      serv.se_user = newstr ("root");
      serv.se_group = newstr (NULL);	/* Group name for root is not portable.  */
      serv.se_bi = bi_lookup (&serv);
      if (!serv.se_bi)
	{
	  /* Should not happen */
	  freeconfig (&serv);
	  if (debug)
	    fprintf (stderr,
		     "INTERNAL ERROR: could not find tcpmux built-in");
	  syslog (LOG_ERR, "INTERNAL ERROR: could not find tcpmux built-in");
	  return;
	}
      serv.se_wait = serv.se_bi->bi_wait;
      serv.se_server = newstr ("internal");
      serv.se_fd = -1;
      serv.se_type = NORM_TYPE;
#ifdef IPV6
      serv.se_proto = newstr ("tcp6");
      serv.se_family = AF_INET6;
      serv.se_v4mapped = 1;
#else
      serv.se_proto = newstr ("tcp");
      serv.se_family = AF_INET;
#endif
      if (debug)
	fprintf (stderr, "inserting default tcpmux entry\n");
      syslog (LOG_INFO, "inserting default tcpmux entry");
      expand_enter (&serv);
    }
}

void
config (int signo)
{
  int i;
  struct stat stats;
  struct servtab *sep;

  for (sep = servtab; sep; sep = sep->se_next)
    sep->se_checked = 0;

  for (i = 0; config_files[i]; i++)
    {
      struct stat statbuf;

      if (stat (config_files[i], &statbuf) == 0)
	{
	  if (S_ISDIR (statbuf.st_mode))
	    {
	      DIR *dirp = opendir (config_files[i]);

	      if (dirp)
		{
		  struct dirent *dp;

		  while ((dp = readdir (dirp)) != NULL)
		    {
		      char *path = calloc (strlen (config_files[i])
					   + strlen (dp->d_name) + 2, 1);
		      if (path)
			{
			  sprintf (path, "%s/%s", config_files[i],
				   dp->d_name);
			  if (stat (path, &stats) == 0
			      && S_ISREG (stats.st_mode))
			    {
			      nextconfig (path);
			    }
			  free (path);
			}
		    }
		  closedir (dirp);
		}
	    }
	  else if (S_ISREG (statbuf.st_mode))
	    {
	      nextconfig (config_files[i]);
	    }
	}
      else
	{
	  if (signo == 0)
	    fprintf (stderr, "inetd: %s, %s\n",
		     config_files[i], strerror (errno));
	  else
	    syslog (LOG_ERR, "%s: %m", config_files[i]);
	}
    }

  free (linebuf);
  linebuf = NULL;
  linebufsize = 0;

  fix_tcpmux ();
}



void
set_proc_title (char *a, int s)
{
  socklen_t size;
  char *cp;
#ifdef IPV6
  struct sockaddr_storage saddr;
#else
  struct sockaddr_in saddr;
#endif
  char buf[80];

  cp = Argv[0];
  size = sizeof saddr;
  if (getpeername (s, (struct sockaddr *) &saddr, &size) == 0)
    {
#ifdef IPV6
      int err;
      char buf2[80];

      err = getnameinfo ((struct sockaddr *) &saddr, sizeof (saddr), buf2,
			 sizeof (buf2), NULL, 0, NI_NUMERICHOST);
      if (!err)
	snprintf (buf, sizeof buf, "-%s [%s]", a, buf2);
      else
	snprintf (buf, sizeof buf, "-%s", a);
#else
      snprintf (buf, sizeof buf, "-%s [%s]", a, inet_ntoa (saddr.sin_addr));
#endif
    }
  else
    snprintf (buf, sizeof buf, "-%s", a);
  strncpy (cp, buf, LastArg - cp);
  cp += strlen (cp);
  while (cp < LastArg)
    *cp++ = ' ';
}

/*
 * Internet services provided internally by inetd:
 */
#define BUFSIZE	8192

/* Echo service -- echo data back */
void
echo_stream (int s, struct servtab *sep)
{
  char buffer[BUFSIZE];
  int i;

  set_proc_title (sep->se_service, s);
  while ((i = read (s, buffer, sizeof buffer)) > 0
	 && write (s, buffer, i) > 0)
    ;
  exit (EXIT_SUCCESS);
}

/* Echo service -- echo data back */
void
echo_dg (int s, struct servtab *sep MAYBE_UNUSED)
{
  char buffer[BUFSIZE];
  int i;
  socklen_t size;
#ifdef IPV6
  struct sockaddr_storage sa;
#else
  struct sockaddr sa;
#endif

  size = sizeof sa;
  i = recvfrom (s, buffer, sizeof buffer, 0, (struct sockaddr *) &sa, &size);
  if (i < 0)
    return;
  sendto (s, buffer, i, 0, (struct sockaddr *) &sa, sizeof sa);
}

/* Discard service -- ignore data */
void
discard_stream (int s, struct servtab *sep)
{
  int ret;
  char buffer[BUFSIZE];

  set_proc_title (sep->se_service, s);
  while (1)
    {
      while ((ret = read (s, buffer, sizeof buffer)) > 0)
	;
      if (ret == 0 || errno != EINTR)
	break;
    }
  exit (EXIT_SUCCESS);
}

void
/* Discard service -- ignore data */
discard_dg (int s, struct servtab *sep MAYBE_UNUSED)
{
  char buffer[BUFSIZE];

  read (s, buffer, sizeof buffer);
}

#include <ctype.h>
#define LINESIZ 72
char ring[128];
char *endring;

void
initring (void)
{
  int i;

  endring = ring;

  for (i = 0; i <= 128; ++i)
    if (isprint (i))
      *endring++ = i;
}

/* Character generator */
void
chargen_stream (int s, struct servtab *sep)
{
  int len;
  char *rs, text[LINESIZ + 2];

  set_proc_title (sep->se_service, s);

  if (!endring)
    {
      initring ();
      rs = ring;
    }

  text[LINESIZ] = '\r';
  text[LINESIZ + 1] = '\n';
  for (rs = ring;;)
    {
      len = endring - rs;
      if (len >= 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 (EXIT_SUCCESS);
}

/* Character generator */
void
chargen_dg (int s, struct servtab *sep MAYBE_UNUSED)
{
#ifdef IPV6
  struct sockaddr_storage sa;
#else
  struct sockaddr sa;
#endif
  static char *rs;
  int len;
  socklen_t size;
  char text[LINESIZ + 2];

  if (endring == 0)
    {
      initring ();
      rs = ring;
    }

  size = sizeof sa;
  if (recvfrom (s, text, sizeof text, 0, (struct sockaddr *) &sa, &size) < 0)
    return;

  len = endring - rs;
  if (len >= 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';
  sendto (s, text, sizeof text, 0, (struct sockaddr *) &sa, sizeof sa);
}

/*
 * 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.
 */

long
machtime (void)
{
  struct timeval tv;

  if (gettimeofday (&tv, NULL) < 0)
    {
      if (debug)
	fprintf (stderr, "Unable to get time of day\n");
      return 0L;
    }
#define OFFSET ((unsigned long)25567 * 24*60*60)
  return (htonl ((long) (tv.tv_sec + OFFSET)));
#undef OFFSET
}

void
machtime_stream (int s, struct servtab *sep MAYBE_UNUSED)
{
  long result;

  result = machtime ();
  write (s, (char *) &result, sizeof result);
}

void
machtime_dg (int s, struct servtab *sep MAYBE_UNUSED)
{
  long result;
#ifdef IPV6
  struct sockaddr_storage sa;
#else
  struct sockaddr sa;
#endif
  socklen_t size;

  size = sizeof sa;
  if (recvfrom (s, (char *) &result, sizeof result, 0,
		(struct sockaddr *) &sa, &size) < 0)
    return;
  result = machtime ();
  sendto (s, (char *) &result, sizeof result, 0,
	  (struct sockaddr *) &sa, sizeof sa);
}

void
/* Return human-readable time of day */
daytime_stream (int s, struct servtab *sep MAYBE_UNUSED)
{
  char buffer[256];
  time_t lclock;

  lclock = time ((time_t *) 0);

  sprintf (buffer, "%.24s\r\n", ctime (&lclock));
  write (s, buffer, strlen (buffer));
}

/* Return human-readable time of day */
void
daytime_dg (int s, struct servtab *sep MAYBE_UNUSED)
{
  char buffer[256];
  time_t lclock;
#ifdef IPV6
  struct sockaddr_storage sa;
#else
  struct sockaddr sa;
#endif
  socklen_t size;

  lclock = time ((time_t *) 0);

  size = sizeof sa;
  if (recvfrom (s, buffer, sizeof buffer, 0, (struct sockaddr *) &sa, &size) <
      0)
    return;
  sprintf (buffer, "%.24s\r\n", ctime (&lclock));
  sendto (s, buffer, strlen (buffer), 0, (struct sockaddr *) &sa, sizeof sa);
}

/*
 *  Based on TCPMUX.C by Mark K. Lottor November 1988
 *  sri-nic::ps:<mkl>tcpmux.c
 */


/* # of characters upto \r,\n or \0 */
static int
fd_getline (int fd, char *buf, int len)
{
  int count = 0, n;

  do
    {
      n = read (fd, buf, len - count);
      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;
}

#define MAX_SERV_LEN	(256+2)	/* 2 bytes for \r\n */

#define strwrite(fd, buf)	write(fd, buf, sizeof(buf)-1)

void
tcpmux (int s, struct servtab *sep)
{
  char service[MAX_SERV_LEN + 1];
  int len;

  /* Get requested service name */
  len = fd_getline (s, service, MAX_SERV_LEN);
  if (len < 0)
    {
      strwrite (s, "-Error reading service name\r\n");
      _exit (EXIT_FAILURE);
    }
  service[len] = '\0';

  if (debug)
    fprintf (stderr, "tcpmux: someone wants %s\n", 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;
	  write (s, sep->se_service, strlen (sep->se_service));
	  strwrite (s, "\r\n");
	}
      _exit (EXIT_FAILURE);
    }

  /* Try matching a service in inetd.conf with the request */
  for (sep = servtab; sep; sep = sep->se_next)
    {
      if (ISMUX (sep) && !strcasecmp (service, sep->se_service))
	{
	  if (ISMUXPLUS (sep))
	    {
	      strwrite (s, "+Go\r\n");
	    }
	  run_service (s, sep);
	  return;
	}
    }
  strwrite (s, "-Service not available\r\n");
  exit (EXIT_FAILURE);
}

/* Set TCP environment variables, modelled after djb's ucspi-tcp tools:
   http://cr.yp.to/ucspi-tcp/environment.html
*/
void
prepenv (int ctrl, struct sockaddr *sa_client, socklen_t sa_len)
{
  char str[16];
  /* IP is used both for numeric addresses and for symbolic ones.
   * Being statically allocated, and only for logging purposes,
   * a full MAXPATHLEN is exaggerated, so a compromise is made.  */
  char ip[4 * INET6_ADDRSTRLEN];
  int ret;
#ifdef IPV6
  struct sockaddr_storage sa_server;
#else
  struct sockaddr_in sa_server;
#endif
  socklen_t len = sizeof (sa_server);

  setenv ("PROTO", "TCP", 1);
  unsetenv ("TCPLOCALIP");
  unsetenv ("TCPLOCALHOST");
  unsetenv ("TCPLOCALPORT");
  unsetenv ("TCPREMOTEIP");
  unsetenv ("TCPREMOTEPORT");
  unsetenv ("TCPREMOTEHOST");

  if (getsockname (ctrl, (struct sockaddr *) &sa_server, &len) < 0)
    syslog (LOG_WARNING, "getsockname(): %m");
  else
    {
      ret = getnameinfo ((struct sockaddr *) &sa_server, len,
			 ip, sizeof (ip), str, sizeof (str),
			 NI_NUMERICHOST | NI_NUMERICSERV);
      if (ret == 0)
	{
	  if (setenv ("TCPLOCALIP", ip, 1) < 0)
	    syslog (LOG_WARNING, "setenv (TCPLOCALIP): %m");
	  else if (debug)
	    fprintf (stderr, "Assigned TCPLOCALIP = %s\n", ip);

	  if (setenv ("TCPLOCALPORT", str, 1) < 0)
	    syslog (LOG_WARNING, "setenv (TCPLOCALPORT): %m");
	}
      else
	syslog (LOG_WARNING, "getnameinfo: %s", gai_strerror (ret));

      if (resolve_option)
	{
	  ret = getnameinfo ((struct sockaddr *) &sa_server, len,
			     ip, sizeof (ip), NULL, 0, 0);
	  if (ret != 0)
	    syslog (LOG_WARNING, "getnameinfo: %s", gai_strerror (ret));
	  else if (setenv ("TCPLOCALHOST", ip, 1) < 0)
	    syslog (LOG_WARNING, "setenv(TCPLOCALHOST): %m");
	}
    }

  ret = getnameinfo (sa_client, sa_len, ip, sizeof (ip), str, sizeof (str),
		     NI_NUMERICHOST | NI_NUMERICSERV);
  if (ret == 0)
    {
      if (setenv ("TCPREMOTEIP", ip, 1) < 0)
	syslog (LOG_WARNING, "setenv(TCPREMOTEIP): %m");
      else if (debug)
	fprintf (stderr, "Assigned TCPREMOTEIP = %s\n", ip);

      if (setenv ("TCPREMOTEPORT", str, 1) < 0)
	syslog (LOG_WARNING, "setenv(TCPREMOTEPORT): %m");

      if (resolve_option)
	{
	  ret = getnameinfo (sa_client, sa_len, ip, sizeof (ip), NULL, 0, 0);
	  if (ret != 0)
	    syslog (LOG_WARNING, "getnameinfo: %s", gai_strerror (ret));
	  else if (setenv ("TCPREMOTEHOST", ip, 1) < 0)
	    syslog (LOG_WARNING, "setenv(TCPREMOTEHOST): %m");
	  else if (debug)
	    fprintf (stderr, "Assigned TCPREMOTEHOST = %s\n", ip);
	}
    }
  else
    syslog (LOG_WARNING, "getnameinfo: %s", gai_strerror (ret));
}



int
main (int argc, char *argv[], char *envp[])
{
  int index;
  struct servtab *sep;
  int dofork;
  pid_t pid;

  set_program_name (argv[0]);

  Argv = argv;
  if (envp == 0 || *envp == 0)
    envp = argv;
  while (*envp)
    envp++;
  LastArg = envp[-1] + strlen (envp[-1]);

  /* Parse command line */
  iu_argp_init ("inetd", program_authors);
  argp_parse (&argp, argc, argv, 0, &index, NULL);

  if (resolve_option)
    env_option = true;

  if (index < argc)
    {
      int i;
      config_files = calloc (argc - index + 1, sizeof (*config_files));
      for (i = 0; index < argc; index++, i++)
	{
	  config_files[i] = strdup (argv[index]);
	}
    }
  else
    {
      config_files = calloc (3, sizeof (*config_files));
      config_files[0] = newstr (PATH_INETDCONF);
      config_files[1] = newstr (PATH_INETDDIR);
    }

  if (!foreground)
    {
      if (daemon (0, 0) < 0)
	{
	  syslog (LOG_DAEMON | LOG_ERR,
		  "%s: Unable to enter daemon mode, %m", argv[0]);
	  exit (EXIT_FAILURE);
	};
    }

  openlog ("inetd", LOG_PID | LOG_NOWAIT, LOG_DAEMON);

  if (pidfile_option)
    {
      FILE *fp = fopen (pid_file, "w");
      if (fp != NULL)
	{
	  if (debug)
	    fprintf (stderr, "Using pid-file at \"%s\".\n", pid_file);
	  fprintf (fp, "%d\n", (int) getpid ());
	  fclose (fp);
	}
      else
	syslog (LOG_CRIT, "can't open %s: %s\n", pid_file, strerror (errno));
    }

  signal_set_handler (SIGALRM, retry);
  config (0);
  signal_set_handler (SIGHUP, config);
  signal_set_handler (SIGCHLD, reapchild);
  signal_set_handler (SIGPIPE, SIG_IGN);

  {
    /* space for daemons to overwrite environment for ps */
#define DUMMYSIZE	100
    char dummy[DUMMYSIZE];

    memset (dummy, 'x', DUMMYSIZE - 1);
    dummy[DUMMYSIZE - 1] = '\0';
    setenv ("inetd_dummy", dummy, 1);
  }

  for (;;)
    {
      int n, ctrl;
      fd_set readable;

      if (nsock == 0)
	{
	  SIGSTATUS stat;
	  sigstatus_empty (stat);

	  signal_block (NULL);
	  while (nsock == 0)
	    inetd_pause (stat);
	  signal_unblock (NULL);
	}
      readable = allsock;
      n = select (maxsock + 1, &readable, NULL, NULL, NULL);
      if (n <= 0)
	{
	  if (n < 0 && errno != EINTR)
	    syslog (LOG_WARNING, "select: %m");
	  sleep (1);
	  continue;
	}
      for (sep = servtab; n && sep; sep = sep->se_next)
	if (sep->se_fd != -1 && FD_ISSET (sep->se_fd, &readable))
	  {
	    n--;
	    if (debug)
	      fprintf (stderr, "someone wants %s\n", sep->se_service);
	    if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
	      {
#ifdef IPV6
		struct sockaddr_storage sa_client;
#else
		struct sockaddr_in sa_client;
#endif
		socklen_t len = sizeof (sa_client);

		ctrl = accept (sep->se_fd, (struct sockaddr *) &sa_client,
			       &len);
		if (debug)
		  fprintf (stderr, "accept, ctrl %d\n", ctrl);
		if (ctrl < 0)
		  {
		    if (errno != EINTR)
		      syslog (LOG_WARNING, "accept (for %s): %m",
			      sep->se_service);
		    continue;
		  }
		if (env_option)
		  prepenv (ctrl, (struct sockaddr *) &sa_client, len);
	      }
	    else
	      ctrl = sep->se_fd;

	    signal_block (NULL);
	    pid = 0;
	    dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
	    if (dofork)
	      {
		if (sep->se_count++ == 0)
		  gettimeofday (&sep->se_time, NULL);
		else if ((sep->se_max && sep->se_count > sep->se_max)
			 || sep->se_count >= toomany)
		  {
		    struct timeval now;

		    gettimeofday (&now, NULL);
		    if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL)
		      {
			sep->se_time = now;
			sep->se_count = 1;
		      }
		    else
		      {
			syslog (LOG_ERR,
				"%s/%s server failing (looping), service terminated",
				sep->se_service, sep->se_proto);
			close_sep (sep);
			if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
			  close (ctrl);
			signal_unblock (NULL);
			if (!timingout)
			  {
			    timingout = 1;
			    alarm (RETRYTIME);
			  }
			continue;
		      }
		  }
		pid = fork ();
	      }
	    if (pid < 0)
	      {
		syslog (LOG_ERR, "fork: %m");
		if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
		  close (ctrl);
		signal_unblock (NULL);
		sleep (1);
		continue;
	      }
	    if (pid && sep->se_wait)
	      {
		sep->se_wait = pid;
		if (sep->se_fd >= 0)
		  {
		    FD_CLR (sep->se_fd, &allsock);
		    nsock--;
		  }
	      }
	    signal_unblock (NULL);
	    if (pid == 0)
	      {
		if (debug && dofork)
		  setsid ();
		if (dofork)
		  {
		    int sock;
		    if (debug)
		      fprintf (stderr, "+ Closing from %d\n", maxsock);
		    for (sock = maxsock; sock > 2; sock--)
		      if (sock != ctrl)
			close (sock);
		  }
		run_service (ctrl, sep);
	      }
	    if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
	      close (ctrl);
	  }
    }
}