NetBSD-5.0.2/usr.sbin/inetd/inetd.c
/* $NetBSD: inetd.c,v 1.107 2008/08/04 03:55:48 tls Exp $ */
/*-
* Copyright (c) 1998, 2003 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center and by Matthias Scheler.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1983, 1991, 1993, 1994\
The Regents of the University of California. All rights reserved.");
#if 0
static char sccsid[] = "@(#)inetd.c 8.4 (Berkeley) 4/13/94";
#else
__RCSID("$NetBSD: inetd.c,v 1.107 2008/08/04 03:55:48 tls Exp $");
#endif
#endif /* not lint */
/*
* 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[:accf[,arg]] stream/dgram/raw/rdm/seqpacket,
only stream can name an accept filter
* protocol must be in /etc/protocols
* wait/nowait[:max] single-threaded/multi-threaded, max #
* user[:group] user/group to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS (20)
*
* For RPC services
* service name/version must be in /etc/rpc
* socket type stream/dgram/raw/rdm/seqpacket
* protocol must be in /etc/protocols
* wait/nowait[:max] single-threaded/multi-threaded
* user[:group] user to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS (20)
*
* For non-RPC services, the "service name" can be of the form
* hostaddress:servicename, in which case the hostaddress is used
* as the host portion of the address to listen on. If hostaddress
* consists of a single `*' character, INADDR_ANY is used.
*
* A line can also consist of just
* hostaddress:
* where hostaddress is as in the preceding paragraph. Such a line must
* have no further fields; the specified hostaddress is remembered and
* used for all further lines that have no hostaddress specified,
* until the next such line (or EOF). (This is why * is provided to
* allow explicit specification of INADDR_ANY.) A line
* *:
* is implicitly in effect at the beginning of the file.
*
* The hostaddress specifier may (and often will) contain dots;
* the service name must not.
*
* For RPC services, host-address specifiers are accepted and will
* work to some extent; however, because of limitations in the
* portmapper interface, it will not work to try to give more than
* one line for any given RPC service, even if the host-address
* specifiers are different.
*
* 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.
*
* #ifdef IPSEC
* Comment lines that start with "#@" denote IPsec policy string, as described
* in ipsec_set_policy(3). This will affect all the following items in
* inetd.conf(8). To reset the policy, just use "#@" line. By default,
* there's no IPsec policy.
* #endif
*/
/*
* Here's the scoop concerning the user:group feature:
*
* 1) set-group-option off.
*
* a) user = root: NO setuid() or setgid() is done
*
* b) other: setuid()
* setgid(primary group as found in passwd)
* initgroups(name, primary group)
*
* 2) set-group-option on.
*
* a) user = root: NO setuid()
* setgid(specified group)
* NO initgroups()
*
* b) other: setuid()
* setgid(specified group)
* initgroups(name, specified group)
*
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/event.h>
#ifndef RLIMIT_NOFILE
#define RLIMIT_NOFILE RLIMIT_OFILE
#endif
#ifndef NO_RPC
#define RPC
#endif
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef RPC
#include <rpc/rpc.h>
#include <rpc/rpcb_clnt.h>
#include <netconfig.h>
#endif
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <util.h>
#include <ifaddrs.h>
#include "pathnames.h"
#ifdef IPSEC
#include <netinet6/ipsec.h>
#ifndef IPSEC_POLICY_IPSEC /* no ipsec support on old ipsec */
#undef IPSEC
#endif
#include "ipsec.h"
#endif
#ifdef LIBWRAP
# include <tcpd.h>
#ifndef LIBWRAP_ALLOW_FACILITY
# define LIBWRAP_ALLOW_FACILITY LOG_AUTH
#endif
#ifndef LIBWRAP_ALLOW_SEVERITY
# define LIBWRAP_ALLOW_SEVERITY LOG_INFO
#endif
#ifndef LIBWRAP_DENY_FACILITY
# define LIBWRAP_DENY_FACILITY LOG_AUTH
#endif
#ifndef LIBWRAP_DENY_SEVERITY
# define LIBWRAP_DENY_SEVERITY LOG_WARNING
#endif
int allow_severity = LIBWRAP_ALLOW_FACILITY|LIBWRAP_ALLOW_SEVERITY;
int deny_severity = LIBWRAP_DENY_FACILITY|LIBWRAP_DENY_SEVERITY;
#endif
#define TOOMANY 40 /* 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 */
#define A_CNT(a) (sizeof (a) / sizeof (a[0]))
int debug;
#ifdef LIBWRAP
int lflag;
#endif
int maxsock;
int kq;
int options;
int timingout;
struct servent *sp;
char *curdom;
const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
#ifndef OPEN_MAX
#define OPEN_MAX 64
#endif
/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
#define FD_MARGIN (8)
rlim_t rlim_ofile_cur = OPEN_MAX;
#ifdef RLIMIT_NOFILE
struct rlimit rlim_ofile;
#endif
struct kevent changebuf[64];
size_t changes;
struct servtab {
char *se_hostaddr; /* host address to listen on */
char *se_service; /* name of service */
int se_socktype; /* type of socket to use */
int se_family; /* address family */
char *se_proto; /* protocol used */
int se_sndbuf; /* sndbuf size */
int se_rcvbuf; /* rcvbuf size */
int se_rpcprog; /* rpc program number */
int se_rpcversl; /* rpc program lowest version */
int se_rpcversh; /* rpc program highest version */
#define isrpcservice(sep) ((sep)->se_rpcversl != 0)
pid_t se_wait; /* single threaded server */
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 */
#define MAXARGV 20
char *se_argv[MAXARGV+1]; /* program arguments */
#ifdef IPSEC
char *se_policy; /* IPsec poilcy string */
#endif
struct accept_filter_arg se_accf; /* accept filter for stream service */
int se_fd; /* open descriptor */
int se_type; /* type */
union {
struct sockaddr se_un_ctrladdr;
struct sockaddr_in se_un_ctrladdr_in;
struct sockaddr_in6 se_un_ctrladdr_in6;
struct sockaddr_un se_un_ctrladdr_un;
} se_un; /* bound address */
#define se_ctrladdr se_un.se_un_ctrladdr
#define se_ctrladdr_in se_un.se_un_ctrladdr_in
#define se_ctrladdr_un se_un.se_un_ctrladdr_un
int se_ctrladdr_size;
int se_max; /* max # of instances of this service */
int se_count; /* number started since se_time */
struct timeval se_time; /* start of se_count */
#ifdef MULOG
int se_log;
#define MULOG_RFC931 0x40000000
#endif
struct servtab *se_next;
} *servtab;
#define NORM_TYPE 0
#define MUX_TYPE 1
#define MUXPLUS_TYPE 2
#define FAITH_TYPE 3
#define ISMUX(sep) (((sep)->se_type == MUX_TYPE) || \
((sep)->se_type == MUXPLUS_TYPE))
#define ISMUXPLUS(sep) ((sep)->se_type == MUXPLUS_TYPE)
static void chargen_dg(int, struct servtab *);
static void chargen_stream(int, struct servtab *);
static void close_sep(struct servtab *);
static void config(void);
static void daytime_dg(int, struct servtab *);
static void daytime_stream(int, struct servtab *);
static void discard_dg(int, struct servtab *);
static void discard_stream(int, struct servtab *);
static void echo_dg(int, struct servtab *);
static void echo_stream(int, struct servtab *);
static void endconfig(void);
static struct servtab *enter(struct servtab *);
static void freeconfig(struct servtab *);
static struct servtab *getconfigent(void);
static void goaway(void);
static void machtime_dg(int, struct servtab *);
static void machtime_stream(int, struct servtab *);
static char *newstr(char *);
static char *nextline(FILE *);
static void print_service(char *, struct servtab *);
static void reapchild(void);
static void retry(void);
static void run_service(int, struct servtab *, int);
static int setconfig(void);
static void setup(struct servtab *);
static char *sskip(char **);
static char *skip(char **);
static void tcpmux(int, struct servtab *);
static void usage(void);
static void register_rpc(struct servtab *);
static void unregister_rpc(struct servtab *);
static void bump_nofile(void);
static void inetd_setproctitle(char *, int);
static void initring(void);
static uint32_t machtime(void);
static int port_good_dg(struct sockaddr *);
static int dg_broadcast(struct in_addr *);
static int my_kevent(const struct kevent *, size_t, struct kevent *,
size_t);
static struct kevent * allocchange(void);
static int getline(int, char *, int);
static void spawn(struct servtab *, int);
#ifdef MULOG
static void dolog(struct servtab *, int);
static void timeout(int);
static char *rfc931_name(struct sockaddr *, int);
#endif
struct biltin {
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, 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 1970 */
{ "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 }
};
/* list of "bad" ports. I.e. ports that are most obviously used for
* "cycling packets" denial of service attacks. See /etc/services.
* List must end with port number "0".
*/
u_int16_t bad_ports[] = { 7, 9, 13, 19, 37, 0 };
#define NUMINT (sizeof(intab) / sizeof(struct inent))
char *CONFIG = _PATH_INETDCONF;
static int my_signals[] =
{ SIGALRM, SIGHUP, SIGCHLD, SIGTERM, SIGINT, SIGPIPE };
int
main(int argc, char *argv[])
{
int ch, n, reload = 1;
while ((ch = getopt(argc, argv,
#ifdef LIBWRAP
"dl"
#else
"d"
#endif
)) != -1)
switch(ch) {
case 'd':
debug = 1;
options |= SO_DEBUG;
break;
#ifdef LIBWRAP
case 'l':
lflag = 1;
break;
#endif
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc > 0)
CONFIG = argv[0];
if (!debug)
daemon(0, 0);
openlog("inetd", LOG_PID | LOG_NOWAIT, LOG_DAEMON);
pidfile(NULL);
kq = kqueue();
if (kq < 0) {
syslog(LOG_ERR, "kqueue: %m");
return (EXIT_FAILURE);
}
#ifdef RLIMIT_NOFILE
if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
syslog(LOG_ERR, "getrlimit: %m");
} else {
rlim_ofile_cur = rlim_ofile.rlim_cur;
if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
rlim_ofile_cur = OPEN_MAX;
}
#endif
for (n = 0; n < (int)A_CNT(my_signals); n++) {
int signum;
signum = my_signals[n];
if (signum != SIGCHLD)
(void) signal(signum, SIG_IGN);
if (signum != SIGPIPE) {
struct kevent *ev;
ev = allocchange();
EV_SET(ev, signum, EVFILT_SIGNAL, EV_ADD | EV_ENABLE,
0, 0, 0);
}
}
for (;;) {
int ctrl;
struct kevent eventbuf[64], *ev;
struct servtab *sep;
if (reload) {
reload = 0;
config();
}
n = my_kevent(changebuf, changes, eventbuf, A_CNT(eventbuf));
changes = 0;
for (ev = eventbuf; n > 0; ev++, n--) {
if (ev->filter == EVFILT_SIGNAL) {
switch (ev->ident) {
case SIGALRM:
retry();
break;
case SIGCHLD:
reapchild();
break;
case SIGTERM:
case SIGINT:
goaway();
break;
case SIGHUP:
reload = 1;
break;
}
continue;
}
if (ev->filter != EVFILT_READ)
continue;
sep = (struct servtab *)ev->udata;
/* Paranoia */
if ((int)ev->ident != sep->se_fd)
continue;
if (debug)
fprintf(stderr, "someone wants %s\n",
sep->se_service);
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
/* XXX here do the libwrap check-before-accept*/
ctrl = accept(sep->se_fd, NULL, NULL);
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;
}
} else
ctrl = sep->se_fd;
spawn(sep, ctrl);
}
}
}
static void
spawn(struct servtab *sep, int ctrl)
{
int dofork;
pid_t pid;
pid = 0;
#ifdef LIBWRAP_INTERNAL
dofork = 1;
#else
dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
#endif
if (dofork) {
if (sep->se_count++ == 0)
(void)gettimeofday(&sep->se_time, NULL);
else if (sep->se_count >= sep->se_max) {
struct timeval now;
(void)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 max spawn rate (%d in %d seconds) "
"exceeded; service not started",
sep->se_service, sep->se_proto,
sep->se_max, CNT_INTVL);
if (!sep->se_wait && sep->se_socktype ==
SOCK_STREAM)
close(ctrl);
close_sep(sep);
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
return;
}
}
pid = fork();
if (pid < 0) {
syslog(LOG_ERR, "fork: %m");
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
close(ctrl);
sleep(1);
return;
}
if (pid != 0 && sep->se_wait) {
struct kevent *ev;
sep->se_wait = pid;
ev = allocchange();
EV_SET(ev, sep->se_fd, EVFILT_READ,
EV_DELETE, 0, 0, 0);
}
if (pid == 0) {
size_t n;
for (n = 0; n < A_CNT(my_signals); n++)
(void) signal(my_signals[n], SIG_DFL);
if (debug)
setsid();
}
}
if (pid == 0) {
run_service(ctrl, sep, dofork);
if (dofork)
exit(0);
}
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
close(ctrl);
}
static void
run_service(int ctrl, struct servtab *sep, int didfork)
{
struct passwd *pwd;
struct group *grp = NULL; /* XXX gcc */
char buf[NI_MAXSERV];
struct servtab *s;
#ifdef LIBWRAP
struct request_info req;
int denied;
char *service = NULL; /* XXX gcc */
#endif
#ifdef LIBWRAP
#ifndef LIBWRAP_INTERNAL
if (sep->se_bi == 0)
#endif
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
request_init(&req, RQ_DAEMON, sep->se_argv[0] ?
sep->se_argv[0] : sep->se_service, RQ_FILE, ctrl, NULL);
fromhost(&req);
denied = !hosts_access(&req);
if (denied || lflag) {
if (getnameinfo(&sep->se_ctrladdr,
sep->se_ctrladdr.sa_len, NULL, 0,
buf, sizeof(buf), 0) != 0) {
/* shouldn't happen */
(void)snprintf(buf, sizeof buf, "%d",
ntohs(sep->se_ctrladdr_in.sin_port));
}
service = buf;
}
if (denied) {
syslog(deny_severity,
"refused connection from %.500s, service %s (%s)",
eval_client(&req), service, sep->se_proto);
goto reject;
}
if (lflag) {
syslog(allow_severity,
"connection from %.500s, service %s (%s)",
eval_client(&req), service, sep->se_proto);
}
}
#endif /* LIBWRAP */
if (sep->se_bi) {
if (didfork) {
for (s = servtab; s; s = s->se_next)
if (s->se_fd != -1 && s->se_fd != ctrl)
close(s->se_fd);
}
(*sep->se_bi->bi_fn)(ctrl, sep);
} else {
if ((pwd = getpwnam(sep->se_user)) == NULL) {
syslog(LOG_ERR, "%s/%s: %s: No such user",
sep->se_service, sep->se_proto, sep->se_user);
goto reject;
}
if (sep->se_group &&
(grp = getgrnam(sep->se_group)) == NULL) {
syslog(LOG_ERR, "%s/%s: %s: No such group",
sep->se_service, sep->se_proto, sep->se_group);
goto reject;
}
if (pwd->pw_uid) {
if (sep->se_group)
pwd->pw_gid = grp->gr_gid;
if (setgid(pwd->pw_gid) < 0) {
syslog(LOG_ERR,
"%s/%s: can't set gid %d: %m", sep->se_service,
sep->se_proto, pwd->pw_gid);
goto reject;
}
(void) initgroups(pwd->pw_name,
pwd->pw_gid);
if (setuid(pwd->pw_uid) < 0) {
syslog(LOG_ERR,
"%s/%s: can't set uid %d: %m", sep->se_service,
sep->se_proto, pwd->pw_uid);
goto reject;
}
} else if (sep->se_group) {
(void) setgid((gid_t)grp->gr_gid);
}
if (debug)
fprintf(stderr, "%d execl %s\n",
getpid(), sep->se_server);
#ifdef MULOG
if (sep->se_log)
dolog(sep, ctrl);
#endif
/* Set our control descriptor to not close-on-exec... */
if (fcntl(ctrl, F_SETFD, 0) < 0)
syslog(LOG_ERR, "fcntl (F_SETFD, 0): %m");
/* ...and dup it to stdin, stdout, and stderr. */
if (ctrl != 0) {
dup2(ctrl, 0);
close(ctrl);
ctrl = 0;
}
dup2(0, 1);
dup2(0, 2);
#ifdef RLIMIT_NOFILE
if (rlim_ofile.rlim_cur != rlim_ofile_cur &&
setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
syslog(LOG_ERR, "setrlimit: %m");
#endif
execv(sep->se_server, sep->se_argv);
syslog(LOG_ERR, "cannot execute %s: %m", sep->se_server);
reject:
if (sep->se_socktype != SOCK_STREAM)
recv(ctrl, buf, sizeof (buf), 0);
_exit(1);
}
}
static void
reapchild(void)
{
int status;
pid_t pid;
struct servtab *sep;
for (;;) {
pid = wait3(&status, WNOHANG, NULL);
if (pid <= 0)
break;
if (debug)
(void) fprintf(stderr, "%d reaped, status %#x\n",
pid, status);
for (sep = servtab; sep != NULL; sep = sep->se_next)
if (sep->se_wait == pid) {
struct kevent *ev;
if (WIFEXITED(status) && WEXITSTATUS(status))
syslog(LOG_WARNING,
"%s: exit status 0x%x",
sep->se_server, WEXITSTATUS(status));
else if (WIFSIGNALED(status))
syslog(LOG_WARNING,
"%s: exit signal 0x%x",
sep->se_server, WTERMSIG(status));
sep->se_wait = 1;
ev = allocchange();
EV_SET(ev, sep->se_fd, EVFILT_READ,
EV_ADD | EV_ENABLE, 0, 0, (intptr_t)sep);
if (debug)
fprintf(stderr, "restored %s, fd %d\n",
sep->se_service, sep->se_fd);
}
}
}
static void
config(void)
{
struct servtab *sep, *cp, **sepp;
size_t n;
if (!setconfig()) {
syslog(LOG_ERR, "%s: %m", CONFIG);
return;
}
for (sep = servtab; sep != NULL; sep = sep->se_next)
sep->se_checked = 0;
while ((cp = getconfigent())) {
for (sep = servtab; sep != NULL; sep = sep->se_next)
if (strcmp(sep->se_service, cp->se_service) == 0 &&
strcmp(sep->se_hostaddr, cp->se_hostaddr) == 0 &&
strcmp(sep->se_proto, cp->se_proto) == 0 &&
ISMUX(sep) == ISMUX(cp))
break;
if (sep != NULL) {
int i;
#define SWAP(type, a, b) {type c = a; a = b; b = c;}
/*
* 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;
SWAP(char *, sep->se_user, cp->se_user);
SWAP(char *, sep->se_group, cp->se_group);
SWAP(char *, sep->se_server, cp->se_server);
for (i = 0; i < MAXARGV; i++)
SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
#ifdef IPSEC
SWAP(char *, sep->se_policy, cp->se_policy);
#endif
SWAP(int, cp->se_type, sep->se_type);
SWAP(int, cp->se_max, sep->se_max);
#undef SWAP
if (isrpcservice(sep))
unregister_rpc(sep);
sep->se_rpcversl = cp->se_rpcversl;
sep->se_rpcversh = cp->se_rpcversh;
freeconfig(cp);
if (debug)
print_service("REDO", sep);
} else {
sep = enter(cp);
if (debug)
print_service("ADD ", sep);
}
sep->se_checked = 1;
switch (sep->se_family) {
case AF_LOCAL:
if (sep->se_fd != -1)
break;
n = strlen(sep->se_service);
if (n > sizeof(sep->se_ctrladdr_un.sun_path)) {
syslog(LOG_ERR, "%s: address too long",
sep->se_service);
sep->se_checked = 0;
continue;
}
(void)unlink(sep->se_service);
strncpy(sep->se_ctrladdr_un.sun_path,
sep->se_service, n);
sep->se_ctrladdr_un.sun_family = AF_LOCAL;
sep->se_ctrladdr_size = n +
sizeof(sep->se_ctrladdr_un) -
sizeof(sep->se_ctrladdr_un.sun_path);
if (!ISMUX(sep))
setup(sep);
break;
case AF_INET:
#ifdef INET6
case AF_INET6:
#endif
{
struct addrinfo hints, *res;
char *host, *port;
int error;
int s;
/* check if the family is supported */
s = socket(sep->se_family, SOCK_DGRAM, 0);
if (s < 0) {
syslog(LOG_WARNING,
"%s/%s: %s: the address family is not "
"supported by the kernel",
sep->se_service, sep->se_proto,
sep->se_hostaddr);
sep->se_checked = 0;
continue;
}
close(s);
memset(&hints, 0, sizeof(hints));
hints.ai_family = sep->se_family;
hints.ai_socktype = sep->se_socktype;
hints.ai_flags = AI_PASSIVE;
if (!strcmp(sep->se_hostaddr, "*"))
host = NULL;
else
host = sep->se_hostaddr;
if (isrpcservice(sep) || ISMUX(sep))
port = "0";
else
port = sep->se_service;
error = getaddrinfo(host, port, &hints, &res);
if (error) {
if (error == EAI_SERVICE) {
/* gai_strerror not friendly enough */
syslog(LOG_WARNING, "%s/%s: "
"unknown service",
sep->se_service, sep->se_proto);
} else {
syslog(LOG_ERR, "%s/%s: %s: %s",
sep->se_service, sep->se_proto,
sep->se_hostaddr,
gai_strerror(error));
}
sep->se_checked = 0;
continue;
}
if (res->ai_next) {
syslog(LOG_ERR,
"%s/%s: %s: resolved to multiple addr",
sep->se_service, sep->se_proto,
sep->se_hostaddr);
sep->se_checked = 0;
freeaddrinfo(res);
continue;
}
memcpy(&sep->se_ctrladdr, res->ai_addr,
res->ai_addrlen);
if (ISMUX(sep)) {
sep->se_fd = -1;
freeaddrinfo(res);
continue;
}
sep->se_ctrladdr_size = res->ai_addrlen;
freeaddrinfo(res);
#ifdef RPC
if (isrpcservice(sep)) {
struct rpcent *rp;
sep->se_rpcprog = atoi(sep->se_service);
if (sep->se_rpcprog == 0) {
rp = getrpcbyname(sep->se_service);
if (rp == 0) {
syslog(LOG_ERR,
"%s/%s: unknown service",
sep->se_service,
sep->se_proto);
sep->se_checked = 0;
continue;
}
sep->se_rpcprog = rp->r_number;
}
if (sep->se_fd == -1 && !ISMUX(sep))
setup(sep);
if (sep->se_fd != -1)
register_rpc(sep);
} else
#endif
{
if (sep->se_fd >= 0)
close_sep(sep);
if (sep->se_fd == -1 && !ISMUX(sep))
setup(sep);
}
}
}
}
endconfig();
/*
* Purge anything not looked at above.
*/
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 (isrpcservice(sep))
unregister_rpc(sep);
if (sep->se_family == AF_LOCAL)
(void)unlink(sep->se_service);
if (debug)
print_service("FREE", sep);
freeconfig(sep);
free(sep);
}
}
static void
retry(void)
{
struct servtab *sep;
timingout = 0;
for (sep = servtab; sep != NULL; sep = sep->se_next) {
if (sep->se_fd == -1 && !ISMUX(sep)) {
switch (sep->se_family) {
case AF_LOCAL:
case AF_INET:
#ifdef INET6
case AF_INET6:
#endif
setup(sep);
if (sep->se_fd != -1 && isrpcservice(sep))
register_rpc(sep);
break;
}
}
}
}
static void
goaway(void)
{
struct servtab *sep;
for (sep = servtab; sep != NULL; sep = sep->se_next) {
if (sep->se_fd == -1)
continue;
switch (sep->se_family) {
case AF_LOCAL:
(void)unlink(sep->se_service);
break;
case AF_INET:
#ifdef INET6
case AF_INET6:
#endif
if (sep->se_wait == 1 && isrpcservice(sep))
unregister_rpc(sep);
break;
}
(void)close(sep->se_fd);
}
exit(0);
}
static void
setup(struct servtab *sep)
{
int on = 1;
#ifdef INET6
int off = 0;
#endif
struct kevent *ev;
if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
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;
}
/* Set all listening sockets to close-on-exec. */
if (fcntl(sep->se_fd, F_SETFD, FD_CLOEXEC) < 0) {
syslog(LOG_ERR, "%s/%s: fcntl(F_SETFD, FD_CLOEXEC): %m",
sep->se_service, sep->se_proto);
close(sep->se_fd);
return;
}
#define turnon(fd, opt) \
setsockopt(fd, SOL_SOCKET, opt, (char *)&on, sizeof (on))
if (strcmp(sep->se_proto, "tcp") == 0 && (options & SO_DEBUG) &&
turnon(sep->se_fd, SO_DEBUG) < 0)
syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
if (turnon(sep->se_fd, SO_REUSEADDR) < 0)
syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
#undef turnon
/* Set the socket buffer sizes, if specified. */
if (sep->se_sndbuf != 0 && setsockopt(sep->se_fd, SOL_SOCKET,
SO_SNDBUF, (char *)&sep->se_sndbuf, sizeof(sep->se_sndbuf)) < 0)
syslog(LOG_ERR, "setsockopt (SO_SNDBUF %d): %m",
sep->se_sndbuf);
if (sep->se_rcvbuf != 0 && setsockopt(sep->se_fd, SOL_SOCKET,
SO_RCVBUF, (char *)&sep->se_rcvbuf, sizeof(sep->se_rcvbuf)) < 0)
syslog(LOG_ERR, "setsockopt (SO_RCVBUF %d): %m",
sep->se_rcvbuf);
#ifdef INET6
if (sep->se_family == AF_INET6) {
int *v;
v = (sep->se_type == FAITH_TYPE) ? &on : &off;
if (setsockopt(sep->se_fd, IPPROTO_IPV6, IPV6_FAITH,
(char *)v, sizeof(*v)) < 0)
syslog(LOG_ERR, "setsockopt (IPV6_FAITH): %m");
}
#endif
#ifdef IPSEC
if (ipsecsetup(sep->se_family, sep->se_fd, sep->se_policy) < 0 &&
sep->se_policy) {
syslog(LOG_ERR, "%s/%s: ipsec setup failed",
sep->se_service, sep->se_proto);
(void)close(sep->se_fd);
sep->se_fd = -1;
return;
}
#endif
if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
if (debug)
fprintf(stderr, "bind failed on %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);
(void) close(sep->se_fd);
sep->se_fd = -1;
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
return;
}
if (sep->se_socktype == SOCK_STREAM)
listen(sep->se_fd, 10);
/* Set the accept filter, if specified. To be done after listen.*/
if (sep->se_accf.af_name[0] != 0 && setsockopt(sep->se_fd, SOL_SOCKET,
SO_ACCEPTFILTER, (char *)&sep->se_accf,
sizeof(sep->se_accf)) < 0)
syslog(LOG_ERR, "setsockopt(SO_ACCEPTFILTER %s): %m",
sep->se_accf.af_name);
ev = allocchange();
EV_SET(ev, sep->se_fd, EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0,
(intptr_t)sep);
if (sep->se_fd > maxsock) {
maxsock = sep->se_fd;
if (maxsock > rlim_ofile_cur - FD_MARGIN)
bump_nofile();
}
if (debug)
fprintf(stderr, "registered %s on %d\n",
sep->se_server, sep->se_fd);
}
/*
* Finish with a service and its socket.
*/
static void
close_sep(struct servtab *sep)
{
if (sep->se_fd >= 0) {
(void) close(sep->se_fd);
sep->se_fd = -1;
}
sep->se_count = 0;
}
static void
register_rpc(struct servtab *sep)
{
#ifdef RPC
struct netbuf nbuf;
struct sockaddr_storage ss;
struct netconfig *nconf;
socklen_t socklen;
int n;
if ((nconf = getnetconfigent(sep->se_proto+4)) == NULL) {
syslog(LOG_ERR, "%s: getnetconfigent failed",
sep->se_proto);
return;
}
socklen = sizeof ss;
if (getsockname(sep->se_fd, (struct sockaddr *)&ss, &socklen) < 0) {
syslog(LOG_ERR, "%s/%s: getsockname: %m",
sep->se_service, sep->se_proto);
return;
}
nbuf.buf = &ss;
nbuf.len = ss.ss_len;
nbuf.maxlen = sizeof (struct sockaddr_storage);
for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
if (debug)
fprintf(stderr, "rpcb_set: %u %d %s %s\n",
sep->se_rpcprog, n, nconf->nc_netid,
taddr2uaddr(nconf, &nbuf));
(void)rpcb_unset(sep->se_rpcprog, n, nconf);
if (!rpcb_set(sep->se_rpcprog, n, nconf, &nbuf))
syslog(LOG_ERR, "rpcb_set: %u %d %s %s%s",
sep->se_rpcprog, n, nconf->nc_netid,
taddr2uaddr(nconf, &nbuf), clnt_spcreateerror(""));
}
#endif /* RPC */
}
static void
unregister_rpc(struct servtab *sep)
{
#ifdef RPC
int n;
struct netconfig *nconf;
if ((nconf = getnetconfigent(sep->se_proto+4)) == NULL) {
syslog(LOG_ERR, "%s: getnetconfigent failed",
sep->se_proto);
return;
}
for (n = sep->se_rpcversl; n <= sep->se_rpcversh; n++) {
if (debug)
fprintf(stderr, "rpcb_unset(%u, %d, %s)\n",
sep->se_rpcprog, n, nconf->nc_netid);
if (!rpcb_unset(sep->se_rpcprog, n, nconf))
syslog(LOG_ERR, "rpcb_unset(%u, %d, %s) failed\n",
sep->se_rpcprog, n, nconf->nc_netid);
}
#endif /* RPC */
}
static struct servtab *
enter(struct servtab *cp)
{
struct servtab *sep;
sep = (struct servtab *)malloc(sizeof (*sep));
if (sep == NULL) {
syslog(LOG_ERR, "Out of memory.");
exit(1);
}
*sep = *cp;
sep->se_fd = -1;
sep->se_rpcprog = -1;
sep->se_next = servtab;
servtab = sep;
return (sep);
}
FILE *fconfig = NULL;
struct servtab serv;
char line[LINE_MAX];
char *defhost;
#ifdef IPSEC
static char *policy = NULL;
#endif
static int
setconfig(void)
{
if (defhost)
free(defhost);
defhost = newstr("*");
#ifdef IPSEC
if (policy)
free(policy);
policy = NULL;
#endif
if (fconfig != NULL) {
fseek(fconfig, 0L, SEEK_SET);
return (1);
}
fconfig = fopen(CONFIG, "r");
return (fconfig != NULL);
}
static void
endconfig(void)
{
if (fconfig != NULL) {
(void) fclose(fconfig);
fconfig = NULL;
}
if (defhost != NULL) {
free(defhost);
defhost = NULL;
}
}
static struct servtab *
getconfigent(void)
{
struct servtab *sep = &serv;
int argc, val;
char *cp, *cp0, *arg, *buf0, *buf1, *sz0, *sz1;
static char TCPMUX_TOKEN[] = "tcpmux/";
#define MUX_LEN (sizeof(TCPMUX_TOKEN)-1)
char *hostdelim;
more:
while ((cp = nextline(fconfig))) {
#ifdef IPSEC
/* lines starting with #@ is not a comment, but the policy */
if (cp[0] == '#' && cp[1] == '@') {
char *p;
for (p = cp + 2; p && *p && isspace((unsigned char)*p); p++)
;
if (*p == '\0') {
if (policy)
free(policy);
policy = NULL;
} else {
if (ipsecsetup_test(p) < 0) {
syslog(LOG_ERR,
"%s: invalid ipsec policy \"%s\"",
CONFIG, p);
exit(1);
} else {
if (policy)
free(policy);
policy = newstr(p);
}
}
}
#endif
if (*cp == '#' || *cp == '\0')
continue;
#ifdef MULOG
/* Avoid use of `skip' if there is a danger of it looking
* at continuation lines.
*/
do {
cp++;
} while (*cp == ' ' || *cp == '\t');
if (*cp == '\0')
continue;
if ((arg = skip(&cp)) == NULL)
continue;
if (strcmp(arg, "DOMAIN"))
continue;
if (curdom)
free(curdom);
curdom = NULL;
while (*cp == ' ' || *cp == '\t')
cp++;
if (*cp == '\0')
continue;
arg = cp;
while (*cp && *cp != ' ' && *cp != '\t')
cp++;
if (*cp != '\0')
*cp++ = '\0';
curdom = newstr(arg);
#endif
break;
}
if (cp == NULL)
return (NULL);
/*
* clear the static buffer, since some fields (se_ctrladdr,
* for example) don't get initialized here.
*/
memset((caddr_t)sep, 0, sizeof *sep);
arg = skip(&cp);
if (cp == NULL) {
/* got an empty line containing just blanks/tabs. */
goto more;
}
/* Check for a host name. */
hostdelim = strrchr(arg, ':');
if (hostdelim) {
*hostdelim = '\0';
if (arg[0] == '[' && hostdelim > arg && hostdelim[-1] == ']') {
hostdelim[-1] = '\0';
sep->se_hostaddr = newstr(arg + 1);
} else
sep->se_hostaddr = newstr(arg);
arg = hostdelim + 1;
/*
* If the line is of the form `host:', then just change the
* default host for the following lines.
*/
if (*arg == '\0') {
arg = skip(&cp);
if (cp == NULL) {
free(defhost);
defhost = sep->se_hostaddr;
goto more;
}
}
} else
sep->se_hostaddr = newstr(defhost);
if (strncmp(arg, TCPMUX_TOKEN, MUX_LEN) == 0) {
char *c = arg + 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(arg);
sep->se_type = NORM_TYPE;
}
arg = sskip(&cp);
if (strncmp(arg, "stream", sizeof("stream") - 1) == 0) {
char *accf, *accf_arg;
sep->se_socktype = SOCK_STREAM;
/* one and only one accept filter */
accf = index(arg, ':');
if (accf) {
if (accf != rindex(arg, ':') || /* more than one */
*(accf + 1) == '\0') { /* nothing beyond */
sep->se_socktype = -1;
} else {
accf++; /* skip delimiter */
strncpy(sep->se_accf.af_name, accf,
sizeof(sep->se_accf.af_name));
accf_arg = index(accf, ',');
if (accf_arg) { /* zero or one arg, no more */
if ((rindex(accf, ',') != accf_arg)) {
sep->se_socktype = -1;
} else {
accf_arg++;
strncpy(sep->se_accf.af_arg,
accf_arg,
sizeof(sep->se_accf.af_arg));
}
}
}
}
}
else if (strcmp(arg, "dgram") == 0)
sep->se_socktype = SOCK_DGRAM;
else if (strcmp(arg, "rdm") == 0)
sep->se_socktype = SOCK_RDM;
else if (strcmp(arg, "seqpacket") == 0)
sep->se_socktype = SOCK_SEQPACKET;
else if (strcmp(arg, "raw") == 0)
sep->se_socktype = SOCK_RAW;
else
sep->se_socktype = -1;
arg = sskip(&cp);
if (sep->se_type == NORM_TYPE &&
strncmp(arg, "faith/", strlen("faith/")) == 0) {
arg += strlen("faith/");
sep->se_type = FAITH_TYPE;
}
sep->se_proto = newstr(arg);
#define MALFORMED(arg) \
do { \
syslog(LOG_ERR, "%s: malformed buffer size option `%s'", \
sep->se_service, (arg)); \
goto more; \
} while (0)
#define GETVAL(arg) \
do { \
if (!isdigit((unsigned char)*(arg))) \
MALFORMED(arg); \
val = strtol((arg), &cp0, 10); \
if (cp0 != NULL) { \
if (cp0[1] != '\0') \
MALFORMED((arg)); \
if (cp0[0] == 'k') \
val *= 1024; \
if (cp0[0] == 'm') \
val *= 1024 * 1024; \
} \
if (val < 1) { \
syslog(LOG_ERR, "%s: invalid buffer size `%s'", \
sep->se_service, (arg)); \
goto more; \
} \
} while (0)
#define ASSIGN(arg) \
do { \
if (strcmp((arg), "sndbuf") == 0) \
sep->se_sndbuf = val; \
else if (strcmp((arg), "rcvbuf") == 0) \
sep->se_rcvbuf = val; \
else \
MALFORMED((arg)); \
} while (0)
/*
* Extract the send and receive buffer sizes before parsing
* the protocol.
*/
sep->se_sndbuf = sep->se_rcvbuf = 0;
buf0 = buf1 = sz0 = sz1 = NULL;
if ((buf0 = strchr(sep->se_proto, ',')) != NULL) {
/* Not meaningful for Tcpmux services. */
if (ISMUX(sep)) {
syslog(LOG_ERR, "%s: can't specify buffer sizes for "
"tcpmux services", sep->se_service);
goto more;
}
/* Skip the , */
*buf0++ = '\0';
/* Check to see if another socket buffer size was specified. */
if ((buf1 = strchr(buf0, ',')) != NULL) {
/* Skip the , */
*buf1++ = '\0';
/* Make sure a 3rd one wasn't specified. */
if (strchr(buf1, ',') != NULL) {
syslog(LOG_ERR, "%s: too many buffer sizes",
sep->se_service);
goto more;
}
/* Locate the size. */
if ((sz1 = strchr(buf1, '=')) == NULL)
MALFORMED(buf1);
/* Skip the = */
*sz1++ = '\0';
}
/* Locate the size. */
if ((sz0 = strchr(buf0, '=')) == NULL)
MALFORMED(buf0);
/* Skip the = */
*sz0++ = '\0';
GETVAL(sz0);
ASSIGN(buf0);
if (buf1 != NULL) {
GETVAL(sz1);
ASSIGN(buf1);
}
}
#undef ASSIGN
#undef GETVAL
#undef MALFORMED
if (strcmp(sep->se_proto, "unix") == 0) {
sep->se_family = AF_LOCAL;
} else {
val = strlen(sep->se_proto);
if (!val) {
syslog(LOG_ERR, "%s: invalid protocol specified",
sep->se_service);
goto more;
}
val = sep->se_proto[val - 1];
switch (val) {
case '4': /*tcp4 or udp4*/
sep->se_family = AF_INET;
break;
#ifdef INET6
case '6': /*tcp6 or udp6*/
sep->se_family = AF_INET6;
break;
#endif
default:
sep->se_family = AF_INET; /*will become AF_INET6*/
break;
}
if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
#ifdef RPC
char *cp, *ccp;
cp = strchr(sep->se_service, '/');
if (cp == 0) {
syslog(LOG_ERR, "%s: no rpc version",
sep->se_service);
goto more;
}
*cp++ = '\0';
sep->se_rpcversl = sep->se_rpcversh =
strtol(cp, &ccp, 0);
if (ccp == cp) {
badafterall:
syslog(LOG_ERR, "%s/%s: bad rpc version",
sep->se_service, cp);
goto more;
}
if (*ccp == '-') {
cp = ccp + 1;
sep->se_rpcversh = strtol(cp, &ccp, 0);
if (ccp == cp)
goto badafterall;
}
#else
syslog(LOG_ERR, "%s: rpc services not suported",
sep->se_service);
goto more;
#endif /* RPC */
}
}
arg = sskip(&cp);
{
char *cp;
if ((cp = strchr(arg, ':')) == NULL)
cp = strchr(arg, '.');
if (cp != NULL) {
*cp++ = '\0';
sep->se_max = atoi(cp);
} else
sep->se_max = TOOMANY;
}
sep->se_wait = strcmp(arg, "wait") == 0;
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: bad protocol for tcpmux service %s",
CONFIG, sep->se_service);
goto more;
}
if (sep->se_socktype != SOCK_STREAM) {
syslog(LOG_ERR,
"%s: bad socket type for tcpmux service %s",
CONFIG, sep->se_service);
goto more;
}
}
sep->se_user = newstr(sskip(&cp));
if ((sep->se_group = strchr(sep->se_user, ':')) != NULL)
*sep->se_group++ = '\0';
else if ((sep->se_group = strchr(sep->se_user, '.')) != NULL)
*sep->se_group++ = '\0';
sep->se_server = newstr(sskip(&cp));
if (strcmp(sep->se_server, "internal") == 0) {
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)
break;
if (bi->bi_service == 0) {
syslog(LOG_ERR, "internal service %s unknown",
sep->se_service);
goto more;
}
sep->se_bi = bi;
sep->se_wait = bi->bi_wait;
} else
sep->se_bi = NULL;
argc = 0;
for (arg = skip(&cp); cp; arg = skip(&cp)) {
#if MULOG
char *colon;
if (argc == 0 && (colon = strrchr(arg, ':'))) {
while (arg < colon) {
int x;
char *ccp;
switch (*arg++) {
case 'l':
x = 1;
if (isdigit(*arg)) {
x = strtol(arg, &ccp, 0);
if (ccp == arg)
break;
arg = ccp;
}
sep->se_log &= ~MULOG_RFC931;
sep->se_log |= x;
break;
case 'a':
sep->se_log |= MULOG_RFC931;
break;
default:
break;
}
}
arg = colon + 1;
}
#endif
if (argc < MAXARGV)
sep->se_argv[argc++] = newstr(arg);
}
while (argc <= MAXARGV)
sep->se_argv[argc++] = NULL;
#ifdef IPSEC
sep->se_policy = policy ? newstr(policy) : NULL;
#endif
return (sep);
}
static void
freeconfig(struct servtab *cp)
{
int i;
if (cp->se_hostaddr)
free(cp->se_hostaddr);
if (cp->se_service)
free(cp->se_service);
if (cp->se_proto)
free(cp->se_proto);
if (cp->se_user)
free(cp->se_user);
/* Note: se_group is part of the newstr'ed se_user */
if (cp->se_server)
free(cp->se_server);
for (i = 0; i < MAXARGV; i++)
if (cp->se_argv[i])
free(cp->se_argv[i]);
#ifdef IPSEC
if (cp->se_policy)
free(cp->se_policy);
#endif
}
/*
* Safe skip - if skip returns null, log a syntax error in the
* configuration file and exit.
*/
static char *
sskip(char **cpp)
{
char *cp;
cp = skip(cpp);
if (cp == NULL) {
syslog(LOG_ERR, "%s: syntax error", CONFIG);
exit(1);
}
return (cp);
}
static char *
skip(char **cpp)
{
char *cp = *cpp;
char *start;
char quote;
if (*cpp == NULL)
return (NULL);
again:
while (*cp == ' ' || *cp == '\t')
cp++;
if (*cp == '\0') {
int c;
c = getc(fconfig);
(void) ungetc(c, fconfig);
if (c == ' ' || c == '\t')
if ((cp = nextline(fconfig)))
goto again;
*cpp = NULL;
return (NULL);
}
start = cp;
quote = '\0';
while (*cp && (quote || (*cp != ' ' && *cp != '\t'))) {
if (*cp == '\'' || *cp == '"') {
if (quote && *cp != quote)
cp++;
else {
if (quote)
quote = '\0';
else
quote = *cp;
memmove(cp, cp+1, strlen(cp));
}
} else
cp++;
}
if (*cp != '\0')
*cp++ = '\0';
*cpp = cp;
return (start);
}
static char *
nextline(FILE *fd)
{
char *cp;
if (fgets(line, sizeof (line), fd) == NULL)
return (NULL);
cp = strchr(line, '\n');
if (cp)
*cp = '\0';
return (line);
}
static char *
newstr(char *cp)
{
if ((cp = strdup((cp != NULL) ? cp : "")) != NULL)
return (cp);
syslog(LOG_ERR, "strdup: %m");
exit(1);
}
static void
inetd_setproctitle(char *a, int s)
{
socklen_t size;
struct sockaddr_storage ss;
char hbuf[NI_MAXHOST], *hp;
size = sizeof(ss);
if (getpeername(s, (struct sockaddr *)&ss, &size) == 0) {
if (getnameinfo((struct sockaddr *)&ss, size, hp = hbuf,
sizeof(hbuf), NULL, 0, niflags) != 0)
hp = "?";
setproctitle("-%s [%s]", a, hp);
} else
setproctitle("-%s", a);
}
static void
bump_nofile(void)
{
#ifdef RLIMIT_NOFILE
#define FD_CHUNK 32
struct rlimit rl;
if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
syslog(LOG_ERR, "getrlimit: %m");
return;
}
rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
if (rl.rlim_cur <= rlim_ofile_cur) {
syslog(LOG_ERR,
"bump_nofile: cannot extend file limit, max = %d",
(int)rl.rlim_cur);
return;
}
if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
syslog(LOG_ERR, "setrlimit: %m");
return;
}
rlim_ofile_cur = rl.rlim_cur;
return;
#else
syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
return;
#endif
}
/*
* Internet services provided internally by inetd:
*/
#define BUFSIZE 4096
/* ARGSUSED */
static void
echo_stream(int s, struct servtab *sep) /* Echo service -- echo data back */
{
char buffer[BUFSIZE];
int i;
inetd_setproctitle(sep->se_service, s);
while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
write(s, buffer, i) > 0)
;
}
/* ARGSUSED */
static void
echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */
{
char buffer[BUFSIZE];
int i;
socklen_t size;
struct sockaddr_storage ss;
struct sockaddr *sa;
sa = (struct sockaddr *)&ss;
size = sizeof(ss);
if ((i = recvfrom(s, buffer, sizeof(buffer), 0, sa, &size)) < 0)
return;
if (port_good_dg(sa))
(void) sendto(s, buffer, i, 0, sa, size);
}
/* ARGSUSED */
static void
discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */
{
char buffer[BUFSIZE];
inetd_setproctitle(sep->se_service, s);
while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
errno == EINTR)
;
}
/* ARGSUSED */
static void
discard_dg(int s, struct servtab *sep) /* Discard service -- ignore data */
{
char buffer[BUFSIZE];
(void) read(s, buffer, sizeof(buffer));
}
#define LINESIZ 72
char ring[128];
char *endring;
static void
initring(void)
{
int i;
endring = ring;
for (i = 0; i <= 128; ++i)
if (isprint(i))
*endring++ = i;
}
/* ARGSUSED */
static void
chargen_stream(int s,struct servtab *sep) /* Character generator */
{
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;
}
}
/* ARGSUSED */
static void
chargen_dg(int s, struct servtab *sep) /* Character generator */
{
struct sockaddr_storage ss;
struct sockaddr *sa;
static char *rs;
int len;
socklen_t size;
char text[LINESIZ+2];
if (endring == 0) {
initring();
rs = ring;
}
sa = (struct sockaddr *)&ss;
size = sizeof(ss);
if (recvfrom(s, text, sizeof(text), 0, sa, &size) < 0)
return;
if (!port_good_dg(sa))
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, sa, size);
}
/*
* 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.
*/
static uint32_t
machtime(void)
{
struct timeval tv;
if (gettimeofday(&tv, NULL) < 0) {
if (debug)
fprintf(stderr, "Unable to get time of day\n");
return (0);
}
#define OFFSET ((uint32_t)25567 * 24*60*60)
return (htonl((uint32_t)(tv.tv_sec + OFFSET)));
#undef OFFSET
}
/* ARGSUSED */
static void
machtime_stream(int s, struct servtab *sep)
{
uint32_t result;
result = machtime();
(void) write(s, (char *) &result, sizeof(result));
}
/* ARGSUSED */
void
machtime_dg(int s, struct servtab *sep)
{
uint32_t result;
struct sockaddr_storage ss;
struct sockaddr *sa;
socklen_t size;
sa = (struct sockaddr *)&ss;
size = sizeof(ss);
if (recvfrom(s, (char *)&result, sizeof(result), 0, sa, &size) < 0)
return;
if (!port_good_dg(sa))
return;
result = machtime();
(void) sendto(s, (char *) &result, sizeof(result), 0, sa, size);
}
/* ARGSUSED */
static void
daytime_stream(int s,struct servtab *sep)
/* Return human-readable time of day */
{
char buffer[256];
time_t clock;
int len;
clock = time((time_t *) 0);
len = snprintf(buffer, sizeof buffer, "%.24s\r\n", ctime(&clock));
(void) write(s, buffer, len);
}
/* ARGSUSED */
void
daytime_dg(int s, struct servtab *sep)
/* Return human-readable time of day */
{
char buffer[256];
time_t clock;
struct sockaddr_storage ss;
struct sockaddr *sa;
socklen_t size;
int len;
clock = time((time_t *) 0);
sa = (struct sockaddr *)&ss;
size = sizeof(ss);
if (recvfrom(s, buffer, sizeof(buffer), 0, sa, &size) < 0)
return;
if (!port_good_dg(sa))
return;
len = snprintf(buffer, sizeof buffer, "%.24s\r\n", ctime(&clock));
(void) sendto(s, buffer, len, 0, sa, size);
}
/*
* print_service:
* Dump relevant information to stderr
*/
static void
print_service(char *action, struct servtab *sep)
{
if (isrpcservice(sep))
fprintf(stderr,
"%s: %s rpcprog=%d, rpcvers = %d/%d, proto=%s, wait.max=%d.%d, user:group=%s:%s builtin=%lx server=%s"
#ifdef IPSEC
" policy=\"%s\""
#endif
"\n",
action, sep->se_service,
sep->se_rpcprog, sep->se_rpcversh, sep->se_rpcversl, sep->se_proto,
sep->se_wait, sep->se_max, sep->se_user, sep->se_group,
(long)sep->se_bi, sep->se_server
#ifdef IPSEC
, (sep->se_policy ? sep->se_policy : "")
#endif
);
else
fprintf(stderr,
"%s: %s proto=%s%s, wait.max=%d.%d, user:group=%s:%s builtin=%lx server=%s"
#ifdef IPSEC
" policy=%s"
#endif
"\n",
action, sep->se_service,
sep->se_type == FAITH_TYPE ? "faith/" : "",
sep->se_proto,
sep->se_wait, sep->se_max, sep->se_user, sep->se_group,
(long)sep->se_bi, sep->se_server
#ifdef IPSEC
, (sep->se_policy ? sep->se_policy : "")
#endif
);
}
static void
usage(void)
{
#ifdef LIBWRAP
(void)fprintf(stderr, "usage: %s [-dl] [conf]\n", getprogname());
#else
(void)fprintf(stderr, "usage: %s [-d] [conf]\n", getprogname());
#endif
exit(1);
}
/*
* Based on TCPMUX.C by Mark K. Lottor November 1988
* sri-nic::ps:<mkl>tcpmux.c
*/
static int /* # of characters upto \r,\n or \0 */
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) (void) write(fd, buf, sizeof(buf)-1)
static void
tcpmux(int ctrl, struct servtab *sep)
{
char service[MAX_SERV_LEN+1];
int len;
/* Get requested service name */
if ((len = getline(ctrl, service, MAX_SERV_LEN)) < 0) {
strwrite(ctrl, "-Error reading service name\r\n");
goto reject;
}
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")) {
strwrite(ctrl, "+Available services:\r\n");
strwrite(ctrl, "help\r\n");
for (sep = servtab; sep != NULL; sep = sep->se_next) {
if (!ISMUX(sep))
continue;
(void)write(ctrl, sep->se_service,
strlen(sep->se_service));
strwrite(ctrl, "\r\n");
}
goto reject;
}
/* Try matching a service in inetd.conf with the request */
for (sep = servtab; sep != NULL; sep = sep->se_next) {
if (!ISMUX(sep))
continue;
if (!strcasecmp(service, sep->se_service)) {
if (ISMUXPLUS(sep))
strwrite(ctrl, "+Go\r\n");
run_service(ctrl, sep, 1 /* forked */);
return;
}
}
strwrite(ctrl, "-Service not available\r\n");
reject:
_exit(1);
}
#ifdef MULOG
void
dolog(struct servtab *sep, int ctrl)
{
struct sockaddr_storage ss;
struct sockaddr *sa = (struct sockaddr *)&ss;
socklen_t len = sizeof(ss);
char *host, *dp, buf[BUFSIZ];
int connected = 1;
switch (sep->se_family) {
case AF_INET:
#ifdef INET6
case AF_INET6:
#endif
break;
default:
return;
}
if (getpeername(ctrl, sa, &len) < 0) {
if (errno != ENOTCONN) {
syslog(LOG_ERR, "getpeername: %m");
return;
}
if (recvfrom(ctrl, buf, sizeof(buf), MSG_PEEK, sa, &len) < 0) {
syslog(LOG_ERR, "recvfrom: %m");
return;
}
connected = 0;
}
switch (sa->sa_family) {
case AF_INET:
#ifdef INET6
case AF_INET6:
#endif
break;
default:
syslog(LOG_ERR, "unexpected address family %u", sa->sa_family);
return;
}
if (getnameinfo(sa, len, buf, sizeof(buf), NULL, 0, 0) != 0)
strlcpy(buf, "?", sizeof(buf));
host = buf;
switch (sep->se_log & ~MULOG_RFC931) {
case 0:
return;
case 1:
if (curdom == NULL || *curdom == '\0')
break;
dp = host + strlen(host) - strlen(curdom);
if (dp < host)
break;
if (debug)
fprintf(stderr, "check \"%s\" against curdom \"%s\"\n",
host, curdom);
if (strcasecmp(dp, curdom) == 0)
return;
break;
case 2:
default:
break;
}
openlog("", LOG_NOWAIT, MULOG);
if (connected && (sep->se_log & MULOG_RFC931))
syslog(LOG_INFO, "%s@%s wants %s",
rfc931_name(sa, ctrl), host, sep->se_service);
else
syslog(LOG_INFO, "%s wants %s",
host, sep->se_service);
}
/*
* From tcp_log by
* Wietse Venema, Eindhoven University of Technology, The Netherlands.
*/
#if 0
static char sccsid[] = "@(#) rfc931.c 1.3 92/08/31 22:54:46";
#endif
#include <setjmp.h>
#define RFC931_PORT 113 /* Semi-well-known port */
#define TIMEOUT 4
#define TIMEOUT2 10
static jmp_buf timebuf;
/* timeout - handle timeouts */
static void
timeout(int sig)
{
longjmp(timebuf, sig);
}
/* rfc931_name - return remote user name */
char *
rfc931_name(struct sockaddr *there, /* remote link information */
int ctrl)
{
struct sockaddr_storage here; /* local link information */
struct sockaddr_storage sin; /* for talking to RFC931 daemon */
socklen_t length;
int s;
unsigned remote;
unsigned local;
static char user[256]; /* XXX */
char buf[256];
char *cp;
char *result = "USER_UNKNOWN";
int len;
u_int16_t myport, hisport;
/* Find out local port number of our stdin. */
length = sizeof(here);
if (getsockname(ctrl, (struct sockaddr *) &here, &length) == -1) {
syslog(LOG_ERR, "getsockname: %m");
return (result);
}
switch (here.ss_family) {
case AF_INET:
myport = ((struct sockaddr_in *)&here)->sin_port;
break;
#ifdef INET6
case AF_INET6:
myport = ((struct sockaddr_in6 *)&here)->sin6_port;
break;
#endif
}
switch (there->sa_family) {
case AF_INET:
hisport = ((struct sockaddr_in *)&there)->sin_port;
break;
#ifdef INET6
case AF_INET6:
hisport = ((struct sockaddr_in6 *)&there)->sin6_port;
break;
#endif
}
/* Set up timer so we won't get stuck. */
if ((s = socket(here.ss_family, SOCK_STREAM, 0)) == -1) {
syslog(LOG_ERR, "socket: %m");
return (result);
}
sin = here;
switch (sin.ss_family) {
case AF_INET:
((struct sockaddr_in *)&sin)->sin_port = htons(0);
break;
#ifdef INET6
case AF_INET6:
((struct sockaddr_in6 *)&sin)->sin6_port = htons(0);
break;
#endif
}
if (bind(s, (struct sockaddr *) &sin, sin.ss_len) == -1) {
syslog(LOG_ERR, "bind: %m");
return (result);
}
signal(SIGALRM, timeout);
if (setjmp(timebuf)) {
close(s); /* not: fclose(fp) */
return (result);
}
alarm(TIMEOUT);
/* Connect to the RFC931 daemon. */
memcpy(&sin, there, there->sa_len);
switch (sin.ss_family) {
case AF_INET:
((struct sockaddr_in *)&sin)->sin_port = htons(RFC931_PORT);
break;
#ifdef INET6
case AF_INET6:
((struct sockaddr_in6 *)&sin)->sin6_port = htons(RFC931_PORT);
break;
#endif
}
if (connect(s, (struct sockaddr *) &sin, sin.ss_len) == -1) {
close(s);
alarm(0);
return (result);
}
/* Query the RFC 931 server. Would 13-byte writes ever be broken up? */
(void)snprintf(buf, sizeof buf, "%u,%u\r\n", ntohs(hisport),
ntohs(myport));
for (len = 0, cp = buf; len < strlen(buf); ) {
int n;
if ((n = write(s, cp, strlen(buf) - len)) == -1) {
close(s);
alarm(0);
return (result);
}
cp += n;
len += n;
}
/* Read response */
for (cp = buf; cp < buf + sizeof(buf) - 1; ) {
char c;
if (read(s, &c, 1) != 1) {
close(s);
alarm(0);
return (result);
}
if (c == '\n')
break;
*cp++ = c;
}
*cp = '\0';
if (sscanf(buf, "%u , %u : USERID :%*[^:]:%255s", &remote, &local,
user) == 3 && ntohs(hisport) == remote && ntohs(myport) == local) {
/* Strip trailing carriage return. */
if ((cp = strchr(user, '\r')) != NULL)
*cp = 0;
result = user;
}
alarm(0);
close(s);
return (result);
}
#endif
/*
* check if the address/port where send data to is one of the obvious ports
* that are used for denial of service attacks like two echo ports
* just echoing data between them
*/
static int
port_good_dg(struct sockaddr *sa)
{
struct in_addr in;
#ifdef INET6
struct in6_addr *in6;
#endif
u_int16_t port;
int i, bad;
char hbuf[NI_MAXHOST];
bad = 0;
switch (sa->sa_family) {
case AF_INET:
in.s_addr = ntohl(((struct sockaddr_in *)sa)->sin_addr.s_addr);
port = ntohs(((struct sockaddr_in *)sa)->sin_port);
#ifdef INET6
v4chk:
#endif
if (IN_MULTICAST(in.s_addr))
goto bad;
switch ((in.s_addr & 0xff000000) >> 24) {
case 0: case 127: case 255:
goto bad;
}
if (dg_broadcast(&in))
goto bad;
break;
#ifdef INET6
case AF_INET6:
in6 = &((struct sockaddr_in6 *)sa)->sin6_addr;
port = ntohs(((struct sockaddr_in6 *)sa)->sin6_port);
if (IN6_IS_ADDR_MULTICAST(in6) || IN6_IS_ADDR_UNSPECIFIED(in6))
goto bad;
if (IN6_IS_ADDR_V4MAPPED(in6) || IN6_IS_ADDR_V4COMPAT(in6)) {
memcpy(&in, &in6->s6_addr[12], sizeof(in));
in.s_addr = ntohl(in.s_addr);
goto v4chk;
}
break;
#endif
default:
/* XXX unsupported af, is it safe to assume it to be safe? */
return (1);
}
for (i = 0; bad_ports[i] != 0; i++) {
if (port == bad_ports[i])
goto bad;
}
return (1);
bad:
if (getnameinfo(sa, sa->sa_len, hbuf, sizeof(hbuf), NULL, 0,
niflags) != 0)
strlcpy(hbuf, "?", sizeof(hbuf));
syslog(LOG_WARNING,"Possible DoS attack from %s, Port %d",
hbuf, port);
return (0);
}
/* XXX need optimization */
static int
dg_broadcast(struct in_addr *in)
{
struct ifaddrs *ifa, *ifap;
struct sockaddr_in *sin;
if (getifaddrs(&ifap) < 0)
return (0);
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (ifa->ifa_addr->sa_family != AF_INET ||
(ifa->ifa_flags & IFF_BROADCAST) == 0)
continue;
sin = (struct sockaddr_in *)ifa->ifa_broadaddr;
if (sin->sin_addr.s_addr == in->s_addr) {
freeifaddrs(ifap);
return (1);
}
}
freeifaddrs(ifap);
return (0);
}
static int
my_kevent(const struct kevent *changelist, size_t nchanges,
struct kevent *eventlist, size_t nevents)
{
int result;
while ((result = kevent(kq, changelist, nchanges, eventlist, nevents,
NULL)) < 0)
if (errno != EINTR) {
syslog(LOG_ERR, "kevent: %m");
exit(EXIT_FAILURE);
}
return (result);
}
static struct kevent *
allocchange(void)
{
if (changes == A_CNT(changebuf)) {
(void) my_kevent(changebuf, A_CNT(changebuf), NULL, 0);
changes = 0;
}
return (&changebuf[changes++]);
}