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freebsd-skq/usr.sbin/inetd/inetd.c
Julian Elischer 0661be0b5d Reviewed by: Bill fenner 
Submitted by:	Archie Cobbs (Archie@whistle.com)

Changes to allow inted to control the number of servers to
start on each service. This is a defence against a denial of service attack
in which the system is made unusable by
an external party. It also allows the behaviour of
small memory systems to be more accuratly predicted, by
bounding the extent to which processes can multiply.
1996-11-10 21:12:44 +00:00

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40 KiB
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/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
static char copyright[] __attribute__ ((unused)) =
"@(#) Copyright (c) 1983, 1991, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
/* from: @(#)inetd.c 8.4 (Berkeley) 4/13/94"; */
static char inetd_c_rcsid[] __attribute__ ((unused)) =
"$Id: inetd.c,v 1.16 1996/11/10 21:07:27 julian Exp $";
#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 stream/dgram/raw/rdm/seqpacket
* protocol must be in /etc/protocols
* wait/nowait single-threaded/multi-threaded
* user user to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS (20)
*
* 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.
*
* 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 single-threaded/multi-threaded
* user user to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS
*
* Comment lines are indicated by a `#' in column 1.
*/
#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 <sys/resource.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <rpc/rpc.h>
#include <rpc/pmap_clnt.h>
#include <errno.h>
#include <fcntl.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 <libutil.h>
#include <sysexits.h>
#include "pathnames.h"
#define TOOMANY 256 /* 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 MAX_MAXCHLD 32767 /* max allowable max children */
#define SIGBLOCK (sigmask(SIGCHLD)|sigmask(SIGHUP)|sigmask(SIGALRM))
int debug = 0;
int log = 0;
int nsock, maxsock;
fd_set allsock;
int options;
int timingout;
int toomany = TOOMANY;
struct servent *sp;
struct rpcent *rpc;
struct in_addr bind_address;
struct servtab {
char *se_service; /* name of service */
int se_socktype; /* type of socket to use */
char *se_proto; /* protocol used */
short se_maxchild; /* max number of children */
short se_numchild; /* current number of children */
pid_t *se_pids; /* array of child pids */
char *se_user; /* user 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 */
int se_fd; /* open descriptor */
struct sockaddr_in se_ctrladdr;/* bound address */
u_char se_type; /* type: normal, mux, or mux+ */
u_char se_checked; /* looked at during merge */
u_char se_accept; /* i.e., wait/nowait mode */
u_char se_rpc; /* ==1 if RPC service */
int se_rpc_prog; /* RPC program number */
u_int se_rpc_lowvers; /* RPC low version */
u_int se_rpc_highvers; /* RPC high version */
int 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)
void chargen_dg __P((int, struct servtab *));
void chargen_stream __P((int, struct servtab *));
void close_sep __P((struct servtab *));
void config __P((int));
void daytime_dg __P((int, struct servtab *));
void daytime_stream __P((int, struct servtab *));
void discard_dg __P((int, struct servtab *));
void discard_stream __P((int, struct servtab *));
void echo_dg __P((int, struct servtab *));
void echo_stream __P((int, struct servtab *));
void endconfig __P((void));
struct servtab *enter __P((struct servtab *));
void freeconfig __P((struct servtab *));
struct servtab *getconfigent __P((void));
void machtime_dg __P((int, struct servtab *));
void machtime_stream __P((int, struct servtab *));
char *newstr __P((char *));
char *nextline __P((FILE *));
void print_service __P((char *, struct servtab *));
void addchild __P((struct servtab *, int));
void reapchild __P((int));
void enable __P((struct servtab *));
void disable __P((struct servtab *));
void retry __P((int));
int setconfig __P((void));
void setup __P((struct servtab *));
char *sskip __P((char **));
char *skip __P((char **));
struct servtab *tcpmux __P((int));
void unregisterrpc __P((register struct servtab *sep));
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_maxchild; /* max number of children (default) */
void (*bi_fn)(); /* 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, (void (*)())tcpmux },
{ NULL }
};
#define NUMINT (sizeof(intab) / sizeof(struct inent))
char *CONFIG = _PATH_INETDCONF;
char *pid_file = _PATH_INETDPID;
#ifdef OLD_SETPROCTITLE
char **Argv;
char *LastArg;
#endif
int
main(argc, argv, envp)
int argc;
char *argv[], *envp[];
{
struct servtab *sep;
struct passwd *pwd;
struct sigvec sv;
int tmpint, ch, dofork;
pid_t pid;
char buf[50];
struct sockaddr_in peer;
int i;
#ifdef OLD_SETPROCTITLE
Argv = argv;
if (envp == 0 || *envp == 0)
envp = argv;
while (*envp)
envp++;
LastArg = envp[-1] + strlen(envp[-1]);
#endif
openlog("inetd", LOG_PID | LOG_NOWAIT, LOG_DAEMON);
bind_address.s_addr = htonl(INADDR_ANY);
while ((ch = getopt(argc, argv, "dlR:a:p:")) != EOF)
switch(ch) {
case 'd':
debug = 1;
options |= SO_DEBUG;
break;
case 'l':
log = 1;
break;
case 'R': { /* invocation rate */
char *p;
tmpint = strtol(optarg, &p, 0);
if (tmpint < 1 || *p)
syslog(LOG_ERR,
"-R %s: bad value for service invocation rate",
optarg);
else
toomany = tmpint;
break;
}
case 'a':
if (!inet_aton(optarg, &bind_address)) {
syslog(LOG_ERR,
"-a %s: invalid IP address", optarg);
exit(EX_USAGE);
}
break;
case 'p':
pid_file = optarg;
break;
case '?':
default:
syslog(LOG_ERR,
"usage: inetd [-dl] [-a address] [-R rate]"
" [-p pidfile] [conf-file]");
exit(EX_USAGE);
}
argc -= optind;
argv += optind;
if (argc > 0)
CONFIG = argv[0];
if (debug == 0) {
FILE *fp;
if (daemon(0, 0) < 0) {
syslog(LOG_WARNING, "daemon(0,0) failed: %m");
}
/*
* In case somebody has started inetd manually, we need to
* clear the logname, so that old servers run as root do not
* get the user's logname..
*/
if (setlogin("") < 0) {
syslog(LOG_WARNING, "cannot clear logname: %m");
/* no big deal if it fails.. */
}
pid = getpid();
fp = fopen(pid_file, "w");
if (fp) {
fprintf(fp, "%ld\n", (long)pid);
fclose(fp);
} else {
syslog(LOG_WARNING, "%s: %m", pid_file);
}
}
memset(&sv, 0, sizeof(sv));
sv.sv_mask = SIGBLOCK;
sv.sv_handler = retry;
sigvec(SIGALRM, &sv, (struct sigvec *)0);
config(SIGHUP);
sv.sv_handler = config;
sigvec(SIGHUP, &sv, (struct sigvec *)0);
sv.sv_handler = reapchild;
sigvec(SIGCHLD, &sv, (struct sigvec *)0);
{
/* space for daemons to overwrite environment for ps */
#define DUMMYSIZE 100
char dummy[DUMMYSIZE];
(void)memset(dummy, 'x', DUMMYSIZE - 1);
dummy[DUMMYSIZE - 1] = '\0';
(void)setenv("inetd_dummy", dummy, 1);
}
for (;;) {
int n, ctrl;
fd_set readable;
if (nsock == 0) {
(void) sigblock(SIGBLOCK);
while (nsock == 0)
sigpause(0L);
(void) sigsetmask(0L);
}
readable = allsock;
if ((n = select(maxsock + 1, &readable, (fd_set *)0,
(fd_set *)0, (struct timeval *)0)) <= 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_accept && sep->se_socktype == SOCK_STREAM) {
ctrl = accept(sep->se_fd, (struct sockaddr *)0,
(int *)0);
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 (log) {
i = sizeof peer;
if(getpeername(ctrl, (struct sockaddr *)
&peer, &i)) {
syslog(LOG_WARNING,
"getpeername(for %s): %m",
sep->se_service);
continue;
}
syslog(LOG_INFO,"%s from %s",
sep->se_service,
inet_ntoa(peer.sin_addr));
}
/*
* Call tcpmux to find the real service to exec.
*/
if (sep->se_bi &&
sep->se_bi->bi_fn == (void (*)()) tcpmux) {
struct servtab *tsep;
tsep = tcpmux(ctrl);
if (tsep == NULL) {
close(ctrl);
continue;
}
sep = tsep;
}
} else
ctrl = sep->se_fd;
(void) sigblock(SIGBLOCK);
pid = 0;
dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
if (dofork) {
if (sep->se_count++ == 0)
(void)gettimeofday(&sep->se_time,
(struct timezone *)0);
else if (sep->se_count >= toomany) {
struct timeval now;
(void)gettimeofday(&now, (struct timezone *)0);
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);
sigsetmask(0L);
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
continue;
}
}
pid = fork();
}
if (pid < 0) {
syslog(LOG_ERR, "fork: %m");
if (sep->se_accept &&
sep->se_socktype == SOCK_STREAM)
close(ctrl);
sigsetmask(0L);
sleep(1);
continue;
}
if (pid)
addchild(sep, pid);
sigsetmask(0L);
if (pid == 0) {
if (dofork) {
if (debug)
fprintf(stderr, "+ Closing from %d\n",
maxsock);
for (tmpint = maxsock; tmpint > 2; tmpint--)
if (tmpint != ctrl)
(void) close(tmpint);
}
if (sep->se_bi) {
(*sep->se_bi->bi_fn)(ctrl, sep);
/* NOTREACHED */
} else {
if (debug)
fprintf(stderr, "%d execl %s\n",
getpid(), sep->se_server);
dup2(ctrl, 0);
close(ctrl);
dup2(0, 1);
dup2(0, 2);
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);
if (sep->se_socktype != SOCK_STREAM)
recv(0, buf, sizeof (buf), 0);
_exit(EX_NOUSER);
}
if (setsid() < 0) {
syslog(LOG_ERR,
"%s: can't setsid(): %m",
sep->se_service);
/* _exit(EX_OSERR); not fatal yet */
}
if (pwd->pw_uid) {
if (setlogin(sep->se_user) < 0) {
syslog(LOG_ERR,
"%s: can't setlogin(%s): %m",
sep->se_service, sep->se_user);
/* _exit(EX_OSERR); not yet */
}
if (setgid(pwd->pw_gid) < 0) {
syslog(LOG_ERR,
"%s: can't set gid %d: %m",
sep->se_service, pwd->pw_gid);
_exit(EX_OSERR);
}
(void) initgroups(pwd->pw_name,
pwd->pw_gid);
if (setuid(pwd->pw_uid) < 0) {
syslog(LOG_ERR,
"%s: can't set uid %d: %m",
sep->se_service, pwd->pw_uid);
_exit(EX_OSERR);
}
}
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(EX_OSERR);
}
}
if (sep->se_accept && sep->se_socktype == SOCK_STREAM)
close(ctrl);
}
}
}
/*
* Record a new child pid for this service. If we've reached the
* limit on children, then stop accepting incoming requests.
*/
void
addchild(struct servtab *sep, pid_t pid)
{
#ifdef SANITY_CHECK
if (sep->se_numchild >= sep->se_maxchild) {
syslog(LOG_ERR, "%s: %d >= %d",
__FUNCTION__, sep->se_numchild, sep->se_maxchild);
exit(EX_SOFTWARE);
}
#endif
if (sep->se_maxchild == 0)
return;
sep->se_pids[sep->se_numchild++] = pid;
if (sep->se_numchild == sep->se_maxchild)
disable(sep);
}
/*
* Some child process has exited. See if it's on somebody's list.
*/
void
reapchild(signo)
int signo;
{
int k, status;
pid_t pid;
struct servtab *sep;
for (;;) {
pid = wait3(&status, WNOHANG, (struct rusage *)0);
if (pid <= 0)
break;
if (debug)
fprintf(stderr, "%d reaped, status %#x\n",
pid, status);
for (sep = servtab; sep; sep = sep->se_next) {
for (k = 0; k < sep->se_numchild; k++)
if (sep->se_pids[k] == pid)
break;
if (k == sep->se_numchild)
continue;
if (sep->se_numchild == sep->se_maxchild)
enable(sep);
sep->se_pids[k] = sep->se_pids[--sep->se_numchild];
if (status)
syslog(LOG_WARNING,
"%s[%d]: exit status 0x%x",
sep->se_server, pid, status);
break;
}
}
}
void
config(signo)
int signo;
{
struct servtab *sep, *new, **sepp;
struct passwd *pwd;
long omask;
if (!setconfig()) {
syslog(LOG_ERR, "%s: %m", CONFIG);
return;
}
for (sep = servtab; sep; sep = sep->se_next)
sep->se_checked = 0;
while ((new = getconfigent())) {
if ((pwd = getpwnam(new->se_user)) == NULL) {
syslog(LOG_ERR,
"%s/%s: No such user '%s', service ignored",
new->se_service, new->se_proto, new->se_user);
continue;
}
for (sep = servtab; sep; sep = sep->se_next)
if (strcmp(sep->se_service, new->se_service) == 0 &&
strcmp(sep->se_proto, new->se_proto) == 0)
break;
if (sep != 0) {
int i;
#define SWAP(a, b) { typeof(a) c = a; a = b; b = c; }
omask = sigblock(SIGBLOCK);
/* copy over outstanding child pids */
if (sep->se_maxchild && new->se_maxchild) {
new->se_numchild = sep->se_numchild;
if (new->se_numchild > new->se_maxchild)
new->se_numchild = new->se_maxchild;
memcpy(new->se_pids, sep->se_pids,
new->se_numchild * sizeof(*new->se_pids));
}
SWAP(sep->se_pids, new->se_pids);
sep->se_maxchild = new->se_maxchild;
sep->se_numchild = new->se_numchild;
/* might need to turn on or off service now */
if (sep->se_fd >= 0) {
if (sep->se_maxchild
&& sep->se_numchild == sep->se_maxchild) {
if (FD_ISSET(sep->se_fd, &allsock))
disable(sep);
} else {
if (!FD_ISSET(sep->se_fd, &allsock))
enable(sep);
}
}
sep->se_accept = new->se_accept;
if (new->se_user)
SWAP(sep->se_user, new->se_user);
if (new->se_server)
SWAP(sep->se_server, new->se_server);
for (i = 0; i < MAXARGV; i++)
SWAP(sep->se_argv[i], new->se_argv[i]);
sigsetmask(omask);
freeconfig(new);
if (debug)
print_service("REDO", sep);
} else {
sep = enter(new);
if (debug)
print_service("ADD ", sep);
}
sep->se_checked = 1;
if (ISMUX(sep)) {
sep->se_fd = -1;
continue;
}
if (!sep->se_rpc) {
sp = getservbyname(sep->se_service, sep->se_proto);
if (sp == 0) {
syslog(LOG_ERR, "%s/%s: unknown service",
sep->se_service, sep->se_proto);
sep->se_checked = 0;
continue;
}
if (sp->s_port != sep->se_ctrladdr.sin_port) {
sep->se_ctrladdr.sin_family = AF_INET;
sep->se_ctrladdr.sin_port = sp->s_port;
if (sep->se_fd >= 0)
close_sep(sep);
}
} else {
rpc = getrpcbyname(sep->se_service);
if (rpc == 0) {
syslog(LOG_ERR, "%s/%s unknown RPC service.",
sep->se_service, sep->se_proto);
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
continue;
}
if (rpc->r_number != sep->se_rpc_prog) {
if (sep->se_rpc_prog)
unregisterrpc(sep);
sep->se_rpc_prog = rpc->r_number;
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
}
}
if (sep->se_fd == -1)
setup(sep);
}
endconfig();
/*
* Purge anything not looked at above.
*/
omask = sigblock(SIGBLOCK);
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);
if (sep->se_rpc && sep->se_rpc_prog > 0)
unregisterrpc(sep);
freeconfig(sep);
free((char *)sep);
}
(void) sigsetmask(omask);
}
void
unregisterrpc(sep)
struct servtab *sep;
{
int i;
struct servtab *sepp;
long omask;
omask = sigblock(SIGBLOCK);
for (sepp = servtab; sepp; sepp = sepp->se_next) {
if (sepp == sep)
continue;
if (sep->se_checked == 0 ||
!sepp->se_rpc ||
sep->se_rpc_prog != sepp->se_rpc_prog)
continue;
return;
}
if (debug)
print_service("UNREG", sep);
for (i = sep->se_rpc_lowvers; i <= sep->se_rpc_highvers; i++)
pmap_unset(sep->se_rpc_prog, i);
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
(void) sigsetmask(omask);
}
void
retry(signo)
int signo;
{
struct servtab *sep;
timingout = 0;
for (sep = servtab; sep; sep = sep->se_next)
if (sep->se_fd == -1 && !ISMUX(sep))
setup(sep);
}
void
setup(sep)
struct servtab *sep;
{
int on = 1;
if ((sep->se_fd = socket(AF_INET, 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;
}
#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");
if (turnon(sep->se_fd, SO_PRIVSTATE) < 0)
syslog(LOG_ERR, "setsockopt (SO_PRIVSTATE): %m");
#undef turnon
if (bind(sep->se_fd, (struct sockaddr *)&sep->se_ctrladdr,
sizeof (sep->se_ctrladdr)) < 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_rpc) {
int i, len = sizeof(struct sockaddr);
if (getsockname(sep->se_fd,
(struct sockaddr*)&sep->se_ctrladdr, &len) < 0){
syslog(LOG_ERR, "%s/%s: getsockname: %m",
sep->se_service, sep->se_proto);
(void) close(sep->se_fd);
sep->se_fd = -1;
return;
}
if (debug)
print_service("REG ", sep);
for (i = sep->se_rpc_lowvers; i <= sep->se_rpc_highvers; i++) {
pmap_unset(sep->se_rpc_prog, i);
pmap_set(sep->se_rpc_prog, i,
(sep->se_socktype == SOCK_DGRAM)
? IPPROTO_UDP : IPPROTO_TCP,
ntohs(sep->se_ctrladdr.sin_port));
}
}
if (sep->se_socktype == SOCK_STREAM)
listen(sep->se_fd, 64);
enable(sep);
if (debug) {
fprintf(stderr, "registered %s on %d\n",
sep->se_server, sep->se_fd);
}
}
/*
* Finish with a service and its socket.
*/
void
close_sep(sep)
struct servtab *sep;
{
if (sep->se_fd >= 0) {
if (FD_ISSET(sep->se_fd, &allsock))
disable(sep);
(void) close(sep->se_fd);
sep->se_fd = -1;
}
sep->se_count = 0;
sep->se_numchild = 0; /* forget about any existing children */
}
struct servtab *
enter(cp)
struct servtab *cp;
{
struct servtab *sep;
long omask;
sep = (struct servtab *)malloc(sizeof (*sep));
if (sep == (struct servtab *)0) {
syslog(LOG_ERR, "Out of memory.");
exit(EX_OSERR);
}
*sep = *cp;
sep->se_fd = -1;
omask = sigblock(SIGBLOCK);
sep->se_next = servtab;
servtab = sep;
sigsetmask(omask);
return (sep);
}
void
enable(struct servtab *sep)
{
if (debug)
fprintf(stderr,
"enabling %s, fd %d", sep->se_service, sep->se_fd);
#ifdef SANITY_CHECK
if (sep->se_fd < 0) {
syslog(LOG_ERR,
"%s: %s: bad fd", __FUNCTION__, sep->se_service);
exit(EX_SOFTWARE);
}
if (ISMUX(sep)) {
syslog(LOG_ERR,
"%s: %s: is mux", __FUNCTION__, sep->se_service);
exit(EX_SOFTWARE);
}
if (FD_ISSET(sep->se_fd, &allsock)) {
syslog(LOG_ERR,
"%s: %s: not off", __FUNCTION__, sep->se_service);
exit(EX_SOFTWARE);
}
#endif
FD_SET(sep->se_fd, &allsock);
nsock++;
if (sep->se_fd > maxsock)
maxsock = sep->se_fd;
}
void
disable(struct servtab *sep)
{
if (debug)
fprintf(stderr,
"disabling %s, fd %d", sep->se_service, sep->se_fd);
#ifdef SANITY_CHECK
if (sep->se_fd < 0) {
syslog(LOG_ERR,
"%s: %s: bad fd", __FUNCTION__, sep->se_service);
exit(EX_SOFTWARE);
}
if (ISMUX(sep)) {
syslog(LOG_ERR,
"%s: %s: is mux", __FUNCTION__, sep->se_service);
exit(EX_SOFTWARE);
}
if (!FD_ISSET(sep->se_fd, &allsock)) {
syslog(LOG_ERR,
"%s: %s: not on", __FUNCTION__, sep->se_service);
exit(EX_SOFTWARE);
}
if (nsock == 0) {
syslog(LOG_ERR, "%s: nsock=0", __FUNCTION__);
exit(EX_SOFTWARE);
}
#endif
FD_CLR(sep->se_fd, &allsock);
nsock--;
if (sep->se_fd == maxsock)
maxsock--;
}
FILE *fconfig = NULL;
struct servtab serv;
char line[LINE_MAX];
int
setconfig()
{
if (fconfig != NULL) {
fseek(fconfig, 0L, SEEK_SET);
return (1);
}
fconfig = fopen(CONFIG, "r");
return (fconfig != NULL);
}
void
endconfig()
{
if (fconfig) {
(void) fclose(fconfig);
fconfig = NULL;
}
}
struct servtab *
getconfigent()
{
struct servtab *sep = &serv;
int argc;
char *cp, *arg, *s;
char *versp;
static char TCPMUX_TOKEN[] = "tcpmux/";
#define MUX_LEN (sizeof(TCPMUX_TOKEN)-1)
more:
while ((cp = nextline(fconfig)) && (*cp == '#' || *cp == '\0'))
;
if (cp == NULL)
return ((struct servtab *)0);
/*
* 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;
}
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 (strcmp(arg, "stream") == 0)
sep->se_socktype = SOCK_STREAM;
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;
sep->se_proto = newstr(sskip(&cp));
if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
memmove(sep->se_proto, sep->se_proto + 4,
strlen(sep->se_proto) + 1 - 4);
sep->se_rpc = 1;
sep->se_rpc_prog = sep->se_rpc_lowvers =
sep->se_rpc_lowvers = 0;
sep->se_ctrladdr.sin_family = AF_INET;
sep->se_ctrladdr.sin_port = 0;
sep->se_ctrladdr.sin_addr = bind_address;
if ((versp = rindex(sep->se_service, '/'))) {
*versp++ = '\0';
switch (sscanf(versp, "%d-%d",
&sep->se_rpc_lowvers,
&sep->se_rpc_highvers)) {
case 2:
break;
case 1:
sep->se_rpc_highvers =
sep->se_rpc_lowvers;
break;
default:
syslog(LOG_ERR,
"bad RPC version specifier; %s\n",
sep->se_service);
freeconfig(sep);
goto more;
}
}
else {
sep->se_rpc_lowvers =
sep->se_rpc_highvers = 1;
}
}
arg = sskip(&cp);
if (!strncmp(arg, "wait", 4))
sep->se_accept = 0;
else if (!strncmp(arg, "nowait", 6))
sep->se_accept = 1;
else {
syslog(LOG_ERR,
"%s: bad wait/nowait for service %s",
CONFIG, sep->se_service);
goto more;
}
sep->se_maxchild = -1;
if ((s = strchr(arg, '/')) != NULL) {
char *eptr;
u_long val;
val = strtoul(s + 1, &eptr, 10);
if (eptr == s + 1 || *eptr || val > MAX_MAXCHLD) {
syslog(LOG_ERR,
"%s: bad max-child for service %s",
CONFIG, sep->se_service);
goto more;
}
sep->se_maxchild = val;
}
if (ISMUX(sep)) {
/*
* Silently enforce "nowait" mode for TCPMUX services
* since they don't have an assigned port to listen on.
*/
sep->se_accept = 1;
if (strcmp(sep->se_proto, "tcp")) {
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));
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_accept = 1; /* force accept mode for built-ins */
sep->se_bi = bi;
} else
sep->se_bi = NULL;
if (sep->se_maxchild < 0) /* apply default max-children */
if (sep->se_bi)
sep->se_maxchild = sep->se_bi->bi_maxchild;
else
sep->se_maxchild = sep->se_accept ? 0 : 1;
if (sep->se_maxchild) {
sep->se_pids = malloc(sep->se_maxchild * sizeof(*sep->se_pids));
if (sep->se_pids == NULL) {
syslog(LOG_ERR, "Out of memory.");
exit(EX_OSERR);
}
}
argc = 0;
for (arg = skip(&cp); cp; arg = skip(&cp))
if (argc < MAXARGV) {
sep->se_argv[argc++] = newstr(arg);
} else {
syslog(LOG_ERR,
"%s: too many arguments for service %s",
CONFIG, sep->se_service);
goto more;
}
while (argc <= MAXARGV)
sep->se_argv[argc++] = NULL;
return (sep);
}
void
freeconfig(cp)
struct servtab *cp;
{
int i;
if (cp->se_service)
free(cp->se_service);
if (cp->se_proto)
free(cp->se_proto);
if (cp->se_user)
free(cp->se_user);
if (cp->se_server)
free(cp->se_server);
if (cp->se_pids)
free(cp->se_pids);
for (i = 0; i < MAXARGV; i++)
if (cp->se_argv[i])
free(cp->se_argv[i]);
}
/*
* Safe skip - if skip returns null, log a syntax error in the
* configuration file and exit.
*/
char *
sskip(cpp)
char **cpp;
{
char *cp;
cp = skip(cpp);
if (cp == NULL) {
syslog(LOG_ERR, "%s: syntax error", CONFIG);
exit(EX_DATAERR);
}
return (cp);
}
char *
skip(cpp)
char **cpp;
{
char *cp = *cpp;
char *start;
char quote = '\0';
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 = (char *)0;
return ((char *)0);
}
if (*cp == '"' || *cp == '\'')
quote = *cp++;
start = cp;
if (quote)
while (*cp && *cp != quote)
cp++;
else
while (*cp && *cp != ' ' && *cp != '\t')
cp++;
if (*cp != '\0')
*cp++ = '\0';
*cpp = cp;
return (start);
}
char *
nextline(fd)
FILE *fd;
{
char *cp;
if (fgets(line, sizeof (line), fd) == NULL)
return ((char *)0);
cp = strchr(line, '\n');
if (cp)
*cp = '\0';
return (line);
}
char *
newstr(cp)
char *cp;
{
if ((cp = strdup(cp ? cp : "")))
return (cp);
syslog(LOG_ERR, "strdup: %m");
exit(EX_OSERR);
}
#ifdef OLD_SETPROCTITLE
void
inetd_setproctitle(a, s)
char *a;
int s;
{
int size;
char *cp;
struct sockaddr_in sin;
char buf[80];
cp = Argv[0];
size = sizeof(sin);
if (getpeername(s, (struct sockaddr *)&sin, &size) == 0)
(void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sin.sin_addr));
else
(void) sprintf(buf, "-%s", a);
strncpy(cp, buf, LastArg - cp);
cp += strlen(cp);
while (cp < LastArg)
*cp++ = ' ';
}
#else
void
inetd_setproctitle(a, s)
char *a;
int s;
{
int size;
struct sockaddr_in sin;
char buf[80];
size = sizeof(sin);
if (getpeername(s, (struct sockaddr *)&sin, &size) == 0)
(void) sprintf(buf, "%s [%s]", a, inet_ntoa(sin.sin_addr));
else
(void) sprintf(buf, "%s", a);
setproctitle("%s", buf);
}
#endif
/*
* Internet services provided internally by inetd:
*/
#define BUFSIZE 8192
/* ARGSUSED */
void
echo_stream(s, sep) /* Echo service -- echo data back */
int s;
struct servtab *sep;
{
char buffer[BUFSIZE];
int i;
inetd_setproctitle(sep->se_service, s);
while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
write(s, buffer, i) > 0)
;
exit(0);
}
int check_loop(sin, sep)
struct sockaddr_in *sin;
struct servtab *sep;
{
struct servtab *se2;
for (se2 = servtab; se2; se2 = se2->se_next) {
if (!se2->se_bi || se2->se_socktype != SOCK_DGRAM)
continue;
if (sin->sin_port == se2->se_ctrladdr.sin_port) {
syslog(LOG_WARNING,
"%s/%s:%s/%s loop request REFUSED from %s",
sep->se_service, sep->se_proto,
se2->se_service, se2->se_proto,
inet_ntoa(sin->sin_addr));
return 1;
}
}
return 0;
}
/* ARGSUSED */
void
echo_dg(s, sep) /* Echo service -- echo data back */
int s;
struct servtab *sep;
{
char buffer[BUFSIZE];
int i, size;
struct sockaddr_in sin;
size = sizeof(sin);
if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
(struct sockaddr *)&sin, &size)) < 0)
return;
if (check_loop(&sin, sep))
return;
(void) sendto(s, buffer, i, 0, (struct sockaddr *)&sin,
sizeof(sin));
}
/* ARGSUSED */
void
discard_stream(s, sep) /* Discard service -- ignore data */
int s;
struct servtab *sep;
{
int ret;
char buffer[BUFSIZE];
inetd_setproctitle(sep->se_service, s);
while (1) {
while ((ret = read(s, buffer, sizeof(buffer))) > 0)
;
if (ret == 0 || errno != EINTR)
break;
}
exit(0);
}
/* ARGSUSED */
void
discard_dg(s, sep) /* Discard service -- ignore data */
int s;
struct servtab *sep;
{
char buffer[BUFSIZE];
(void) read(s, buffer, sizeof(buffer));
}
#include <ctype.h>
#define LINESIZ 72
char ring[128];
char *endring;
void
initring()
{
int i;
endring = ring;
for (i = 0; i <= 128; ++i)
if (isprint(i))
*endring++ = i;
}
/* ARGSUSED */
void
chargen_stream(s, sep) /* Character generator */
int s;
struct servtab *sep;
{
int len;
char *rs, text[LINESIZ+2];
inetd_setproctitle(sep->se_service, s);
if (!endring) {
initring();
rs = ring;
}
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
for (rs = ring;;) {
if ((len = endring - rs) >= LINESIZ)
memmove(text, rs, LINESIZ);
else {
memmove(text, rs, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++rs == endring)
rs = ring;
if (write(s, text, sizeof(text)) != sizeof(text))
break;
}
exit(0);
}
/* ARGSUSED */
void
chargen_dg(s, sep) /* Character generator */
int s;
struct servtab *sep;
{
struct sockaddr_in sin;
static char *rs;
int len, size;
char text[LINESIZ+2];
if (endring == 0) {
initring();
rs = ring;
}
size = sizeof(sin);
if (recvfrom(s, text, sizeof(text), 0,
(struct sockaddr *)&sin, &size) < 0)
return;
if (check_loop(&sin, sep))
return;
if ((len = endring - rs) >= LINESIZ)
memmove(text, rs, LINESIZ);
else {
memmove(text, rs, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++rs == endring)
rs = ring;
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
(void) sendto(s, text, sizeof(text), 0,
(struct sockaddr *)&sin, sizeof(sin));
}
/*
* 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()
{
struct timeval tv;
if (gettimeofday(&tv, (struct timezone *)0) < 0) {
if (debug)
fprintf(stderr, "Unable to get time of day\n");
return (0L);
}
#define OFFSET ((u_long)25567 * 24*60*60)
return (htonl((long)(tv.tv_sec + OFFSET)));
#undef OFFSET
}
/* ARGSUSED */
void
machtime_stream(s, sep)
int s;
struct servtab *sep;
{
long result;
result = machtime();
(void) write(s, (char *) &result, sizeof(result));
}
/* ARGSUSED */
void
machtime_dg(s, sep)
int s;
struct servtab *sep;
{
long result;
struct sockaddr_in sin;
int size;
size = sizeof(sin);
if (recvfrom(s, (char *)&result, sizeof(result), 0,
(struct sockaddr *)&sin, &size) < 0)
return;
if (check_loop(&sin, sep))
return;
result = machtime();
(void) sendto(s, (char *) &result, sizeof(result), 0,
(struct sockaddr *)&sin, sizeof(sin));
}
/* ARGSUSED */
void
daytime_stream(s, sep) /* Return human-readable time of day */
int s;
struct servtab *sep;
{
char buffer[256];
time_t clock;
clock = time((time_t *) 0);
(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
(void) write(s, buffer, strlen(buffer));
}
/* ARGSUSED */
void
daytime_dg(s, sep) /* Return human-readable time of day */
int s;
struct servtab *sep;
{
char buffer[256];
time_t clock;
struct sockaddr_in sin;
int size;
clock = time((time_t *) 0);
size = sizeof(sin);
if (recvfrom(s, buffer, sizeof(buffer), 0,
(struct sockaddr *)&sin, &size) < 0)
return;
if (check_loop(&sin, sep))
return;
(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
(void) sendto(s, buffer, strlen(buffer), 0,
(struct sockaddr *)&sin, sizeof(sin));
}
/*
* print_service:
* Dump relevant information to stderr
*/
void
print_service(action, sep)
char *action;
struct servtab *sep;
{
fprintf(stderr,
"%s: %s proto=%s accept=%d max=%d user=%s builtin=%x server=%s\n",
action, sep->se_service, sep->se_proto,
sep->se_accept, sep->se_maxchild, sep->se_user,
(int)sep->se_bi, sep->se_server);
}
/*
* 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(fd, buf, len)
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)
struct servtab *
tcpmux(s)
int s;
{
struct servtab *sep;
char service[MAX_SERV_LEN+1];
int len;
/* Get requested service name */
if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
strwrite(s, "-Error reading service name\r\n");
return (NULL);
}
service[len] = '\0';
if (debug)
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;
(void)write(s,sep->se_service,strlen(sep->se_service));
strwrite(s, "\r\n");
}
return (NULL);
}
/* Try matching a service in inetd.conf with the request */
for (sep = servtab; sep; sep = sep->se_next) {
if (!ISMUX(sep))
continue;
if (!strcasecmp(service, sep->se_service)) {
if (ISMUXPLUS(sep)) {
strwrite(s, "+Go\r\n");
}
return (sep);
}
}
strwrite(s, "-Service not available\r\n");
return (NULL);
}
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