1 /* vi: set sw=4 ts=4: */
2 /* $Slackware: inetd.c 1.79s 2001/02/06 13:18:00 volkerdi Exp $ */
3 /* $OpenBSD: inetd.c,v 1.79 2001/01/30 08:30:57 deraadt Exp $ */
4 /* $NetBSD: inetd.c,v 1.11 1996/02/22 11:14:41 mycroft Exp $ */
5 /* Busybox port by Vladimir Oleynik (C) 2001-2005 <dzo@simtreas.ru> */
7 * Copyright (c) 1983,1991 The Regents of the University of California.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 /* Inetd - Internet super-server
41 * This program invokes all internet services as needed.
42 * connection-oriented services are invoked each time a
43 * connection is made, by creating a process. This process
44 * is passed the connection as file descriptor 0 and is
45 * expected to do a getpeername to find out the source host
48 * Datagram oriented services are invoked when a datagram
49 * arrives; a process is created and passed a pending message
50 * on file descriptor 0. Datagram servers may either connect
51 * to their peer, freeing up the original socket for inetd
52 * to receive further messages on, or "take over the socket",
53 * processing all arriving datagrams and, eventually, timing
54 * out. The first type of server is said to be "multi-threaded";
55 * the second type of server "single-threaded".
57 * Inetd uses a configuration file which is read at startup
58 * and, possibly, at some later time in response to a hangup signal.
59 * The configuration file is "free format" with fields given in the
60 * order shown below. Continuation lines for an entry must begin with
61 * a space or tab. All fields must be present in each entry.
63 * service name must be in /etc/services
64 * socket type stream/dgram/raw/rdm/seqpacket
65 * protocol must be in /etc/protocols
66 * (usually "tcp" or "udp")
67 * wait/nowait[.max] single-threaded/multi-threaded, max #
68 * user[.group] or user[:group] user/group to run daemon as
69 * server program full path name
70 * server program arguments maximum of MAXARGS (20)
73 * service name/version must be in /etc/rpc
74 * socket type stream/dgram/raw/rdm/seqpacket
75 * rpc/protocol "rpc/tcp" etc
76 * wait/nowait[.max] single-threaded/multi-threaded
77 * user[.group] or user[:group] user to run daemon as
78 * server program full path name
79 * server program arguments maximum of MAXARGS (20)
81 * For non-RPC services, the "service name" can be of the form
82 * hostaddress:servicename, in which case the hostaddress is used
83 * as the host portion of the address to listen on. If hostaddress
84 * consists of a single `*' character, INADDR_ANY is used.
86 * A line can also consist of just
88 * where hostaddress is as in the preceding paragraph. Such a line must
89 * have no further fields; the specified hostaddress is remembered and
90 * used for all further lines that have no hostaddress specified,
91 * until the next such line (or EOF). (This is why * is provided to
92 * allow explicit specification of INADDR_ANY.) A line
94 * is implicitly in effect at the beginning of the file.
96 * The hostaddress specifier may (and often will) contain dots;
97 * the service name must not.
99 * For RPC services, host-address specifiers are accepted and will
100 * work to some extent; however, because of limitations in the
101 * portmapper interface, it will not work to try to give more than
102 * one line for any given RPC service, even if the host-address
103 * specifiers are different.
105 * Comment lines are indicated by a `#' in column 1.
108 /* inetd rules for passing file descriptors to children
109 * (http://www.freebsd.org/cgi/man.cgi?query=inetd):
111 * The wait/nowait entry specifies whether the server that is invoked by
112 * inetd will take over the socket associated with the service access point,
113 * and thus whether inetd should wait for the server to exit before listen-
114 * ing for new service requests. Datagram servers must use "wait", as
115 * they are always invoked with the original datagram socket bound to the
116 * specified service address. These servers must read at least one datagram
117 * from the socket before exiting. If a datagram server connects to its
118 * peer, freeing the socket so inetd can receive further messages on the
119 * socket, it is said to be a "multi-threaded" server; it should read one
120 * datagram from the socket and create a new socket connected to the peer.
121 * It should fork, and the parent should then exit to allow inetd to check
122 * for new service requests to spawn new servers. Datagram servers which
123 * process all incoming datagrams on a socket and eventually time out are
124 * said to be "single-threaded". The comsat(8), biff(1) and talkd(8)
125 * utilities are both examples of the latter type of datagram server. The
126 * tftpd(8) utility is an example of a multi-threaded datagram server.
128 * Servers using stream sockets generally are multi-threaded and use the
129 * "nowait" entry. Connection requests for these services are accepted by
130 * inetd, and the server is given only the newly-accepted socket connected
131 * to a client of the service. Most stream-based services operate in this
132 * manner. Stream-based servers that use "wait" are started with the lis-
133 * tening service socket, and must accept at least one connection request
134 * before exiting. Such a server would normally accept and process incoming
135 * connection requests until a timeout.
138 /* Here's the scoop concerning the user[:group] feature:
139 * 1) group is not specified:
140 * a) user = root: NO setuid() or setgid() is done
141 * b) other: setgid(primary group as found in passwd)
142 * initgroups(name, primary group)
144 * 2) group is specified:
145 * a) user = root: setgid(specified group)
148 * b) other: setgid(specified group)
149 * initgroups(name, specified group)
158 /* stream versions of these builtins are forking,
159 * can't do that (easily) on NOMMU */
160 #undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
161 #define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD 0
162 #undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
163 #define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
166 #if ENABLE_FEATURE_INETD_RPC
168 #include <rpc/pmap_clnt.h>
171 #define _PATH_INETDPID "/var/run/inetd.pid"
173 #define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
174 #define RETRYTIME (60*10) /* retry after bind or server fail */
176 #ifndef RLIMIT_NOFILE
177 #define RLIMIT_NOFILE RLIMIT_OFILE
184 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
187 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
188 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
189 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
190 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
191 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
192 # define INETD_BUILTINS_ENABLED
195 typedef struct servtab_t {
196 /* The most frequently referenced one: */
197 int se_fd; /* open descriptor */
198 /* NB: 'biggest fields last' saves on code size (~250 bytes) */
199 /* [addr:]service socktype proto wait user[:group] prog [args] */
200 char *se_local_hostname; /* addr to listen on */
201 char *se_service; /* "80" or "www" or "mount/2[-3]" */
202 /* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
203 char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
204 #if ENABLE_FEATURE_INETD_RPC
205 int se_rpcprog; /* rpc program number */
206 int se_rpcver_lo; /* rpc program lowest version */
207 int se_rpcver_hi; /* rpc program highest version */
208 #define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
210 #define is_rpc_service(sep) 0
212 pid_t se_wait; /* 0:"nowait", 1:"wait" */
213 socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
214 family_t se_family; /* AF_UNIX/INET[6] */
215 smallint se_proto_no; /* almost "getprotobyname(se_proto)" */
216 smallint se_checked; /* looked at during merge */
217 char *se_user; /* user name to run as */
218 char *se_group; /* group name to run as, can be NULL */
219 #ifdef INETD_BUILTINS_ENABLED
220 const struct builtin *se_builtin; /* if built-in, description */
222 // TODO: wrong algorithm!!!
223 unsigned se_max; /* max # of instances of this service */
224 unsigned se_count; /* number started since se_time */
225 unsigned se_time; /* start of se_count */
226 struct servtab_t *se_next;
227 len_and_sockaddr *se_lsa;
228 char *se_program; /* server program */
230 char *se_argv[MAXARGV + 1]; /* program arguments */
233 #ifdef INETD_BUILTINS_ENABLED
234 /* Echo received data */
235 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
236 static void echo_stream(int, servtab_t *);
237 static void echo_dg(int, servtab_t *);
239 /* Internet /dev/null */
240 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
241 static void discard_stream(int, servtab_t *);
242 static void discard_dg(int, servtab_t *);
244 /* Return 32 bit time since 1900 */
245 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
246 static void machtime_stream(int, servtab_t *);
247 static void machtime_dg(int, servtab_t *);
249 /* Return human-readable time */
250 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
251 static void daytime_stream(int, servtab_t *);
252 static void daytime_dg(int, servtab_t *);
254 /* Familiar character generator */
255 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
256 static void chargen_stream(int, servtab_t *);
257 static void chargen_dg(int, servtab_t *);
261 const char *bi_service; /* internally provided service name */
262 uint8_t bi_fork; /* 1 if stream fn should run in child */
263 /* All builtins are "nowait" */
264 /* uint8_t bi_wait; */ /* 1 if should wait for child */
265 void (*bi_stream_fn)(int, servtab_t *);
266 void (*bi_dgram_fn)(int, servtab_t *);
269 static const struct builtin builtins[] = {
270 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
271 /* Echo received data */
272 { "echo", 1, echo_stream, echo_dg },
274 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
275 /* Internet /dev/null */
276 { "discard", 1, discard_stream, discard_dg },
278 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
279 /* Familiar character generator */
280 { "chargen", 1, chargen_stream, chargen_dg },
282 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
283 /* Return 32 bit time since 1900 */
284 { "time", 0, machtime_stream, machtime_dg },
286 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
287 /* Return human-readable time */
288 { "daytime", 0, daytime_stream, daytime_dg },
291 #endif /* INETD_BUILTINS_ENABLED */
294 rlim_t rlim_ofile_cur;
295 struct rlimit rlim_ofile;
296 servtab_t *serv_list;
300 unsigned max_concurrency;
301 smallint alarm_armed;
302 uid_t real_uid; /* user ID who ran us */
303 unsigned config_lineno;
304 const char *config_filename;
306 char *default_local_hostname;
307 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
313 /* Used in next_line(), and as scratch read buffer */
314 char line[256]; /* _at least_ 256, see LINE_SIZE */
316 #define G (*(struct globals*)&bb_common_bufsiz1)
317 enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
318 struct BUG_G_too_big {
319 char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
321 #define rlim_ofile_cur (G.rlim_ofile_cur )
322 #define rlim_ofile (G.rlim_ofile )
323 #define serv_list (G.serv_list )
324 #define global_queuelen (G.global_queuelen)
325 #define prev_maxsock (G.prev_maxsock )
326 #define maxsock (G.maxsock )
327 #define max_concurrency (G.max_concurrency)
328 #define alarm_armed (G.alarm_armed )
329 #define real_uid (G.real_uid )
330 #define config_lineno (G.config_lineno )
331 #define config_filename (G.config_filename)
332 #define fconfig (G.fconfig )
333 #define default_local_hostname (G.default_local_hostname)
334 #define first_ps_byte (G.first_ps_byte )
335 #define last_ps_byte (G.last_ps_byte )
336 #define endring (G.endring )
337 #define ringpos (G.ringpos )
338 #define ring (G.ring )
339 #define allsock (G.allsock )
340 #define line (G.line )
341 #define INIT_G() do { \
342 rlim_ofile_cur = OPEN_MAX; \
343 global_queuelen = 128; \
344 config_filename = "/etc/inetd.conf"; \
347 static void maybe_close(int fd)
353 // TODO: move to libbb?
354 static len_and_sockaddr *xzalloc_lsa(int family)
356 len_and_sockaddr *lsa;
359 sz = sizeof(struct sockaddr_in);
360 #if ENABLE_FEATURE_IPV6
361 if (family == AF_INET6)
362 sz = sizeof(struct sockaddr_in6);
364 lsa = xzalloc(LSA_LEN_SIZE + sz);
366 lsa->u.sa.sa_family = family;
371 static void rearm_alarm(void)
379 static void block_CHLD_HUP_ALRM(sigset_t *m)
382 sigaddset(m, SIGCHLD);
383 sigaddset(m, SIGHUP);
384 sigaddset(m, SIGALRM);
385 sigprocmask(SIG_BLOCK, m, NULL);
388 static void unblock_sigs(sigset_t *m)
390 sigprocmask(SIG_UNBLOCK, m, NULL);
393 #if ENABLE_FEATURE_INETD_RPC
394 static void register_rpc(servtab_t *sep)
397 struct sockaddr_in ir_sin;
400 size = sizeof(ir_sin);
401 if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
402 bb_perror_msg("getsockname");
406 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
407 pmap_unset(sep->se_rpcprog, n);
408 if (!pmap_set(sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port)))
409 bb_perror_msg("%s %s: pmap_set(%u,%u,%u,%u)",
410 sep->se_service, sep->se_proto,
411 sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port));
415 static void unregister_rpc(servtab_t *sep)
419 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
420 if (!pmap_unset(sep->se_rpcprog, n))
421 bb_perror_msg("pmap_unset(%u,%u)", sep->se_rpcprog, n);
424 #endif /* FEATURE_INETD_RPC */
426 static void bump_nofile(void)
428 enum { FD_CHUNK = 32 };
431 /* Never fails under Linux (except if you pass it bad arguments) */
432 getrlimit(RLIMIT_NOFILE, &rl);
433 rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
434 rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
435 if (rl.rlim_cur <= rlim_ofile_cur) {
436 bb_error_msg("can't extend file limit, max = %d",
441 if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
442 bb_perror_msg("setrlimit");
446 rlim_ofile_cur = rl.rlim_cur;
449 static void remove_fd_from_set(int fd)
452 FD_CLR(fd, &allsock);
457 static void add_fd_to_set(int fd)
460 FD_SET(fd, &allsock);
461 if (maxsock >= 0 && fd > maxsock) {
462 prev_maxsock = maxsock = fd;
463 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
469 static void recalculate_maxsock(void)
472 while (fd <= prev_maxsock) {
473 if (FD_ISSET(fd, &allsock))
477 prev_maxsock = maxsock;
478 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
482 static void prepare_socket_fd(servtab_t *sep)
486 fd = socket(sep->se_family, sep->se_socktype, 0);
488 bb_perror_msg("socket");
491 setsockopt_reuseaddr(fd);
493 #if ENABLE_FEATURE_INETD_RPC
494 if (is_rpc_service(sep)) {
497 /* zero out the port for all RPC services; let bind()
499 set_nport(sep->se_lsa, 0);
501 /* for RPC services, attempt to use a reserved port
502 * if they are going to be running as root. */
503 if (real_uid == 0 && sep->se_family == AF_INET
504 && (pwd = getpwnam(sep->se_user)) != NULL
507 r = bindresvport(fd, &sep->se_lsa->u.sin);
509 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
512 int saveerrno = errno;
513 /* update lsa with port# */
514 getsockname(fd, &sep->se_lsa->u.sa, &sep->se_lsa->len);
520 if (sep->se_family == AF_UNIX) {
521 struct sockaddr_un *sun;
522 sun = (struct sockaddr_un*)&(sep->se_lsa->u.sa);
523 unlink(sun->sun_path);
525 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
528 bb_perror_msg("%s/%s: bind",
529 sep->se_service, sep->se_proto);
534 if (sep->se_socktype == SOCK_STREAM)
535 listen(fd, global_queuelen);
541 static int reopen_config_file(void)
543 free(default_local_hostname);
544 default_local_hostname = xstrdup("*");
548 fconfig = fopen_or_warn(config_filename, "r");
549 return (fconfig != NULL);
552 static void close_config_file(void)
560 static char *next_line(void)
562 if (fgets(line, LINE_SIZE, fconfig) == NULL)
565 *strchrnul(line, '\n') = '\0';
569 static char *next_word(char **cpp)
577 while (*cp == ' ' || *cp == '\t')
580 int c = getc(fconfig);
582 if (c == ' ' || c == '\t') {
591 while (*cp && *cp != ' ' && *cp != '\t')
600 static void free_servtab_strings(servtab_t *cp)
604 free(cp->se_local_hostname);
605 free(cp->se_service);
609 free(cp->se_lsa); /* not a string in fact */
610 free(cp->se_program);
611 for (i = 0; i < MAXARGV; i++)
612 free(cp->se_argv[i]);
615 static servtab_t *new_servtab(void)
617 servtab_t *newtab = xzalloc(sizeof(servtab_t));
618 newtab->se_fd = -1; /* paranoia */
622 static servtab_t *dup_servtab(servtab_t *sep)
627 newtab = new_servtab();
628 *newtab = *sep; /* struct copy */
629 /* deep-copying strings */
630 newtab->se_service = xstrdup(newtab->se_service);
631 newtab->se_proto = xstrdup(newtab->se_proto);
632 newtab->se_user = xstrdup(newtab->se_user);
633 newtab->se_group = xstrdup(newtab->se_group);
634 newtab->se_program = xstrdup(newtab->se_program);
635 for (argc = 0; argc <= MAXARGV; argc++)
636 newtab->se_argv[argc] = xstrdup(newtab->se_argv[argc]);
637 /* NB: se_fd, se_hostaddr and se_next are always
638 * overwrittend by callers, so we don't bother resetting them
639 * to NULL/0/-1 etc */
644 /* gcc generates much more code if this is inlined */
645 static NOINLINE servtab_t *parse_one_line(void)
655 while ((cp = next_line()) && *cp == '#')
656 continue; /* skip comment lines */
662 arg = next_word(&cp);
668 /* [host:]service socktype proto wait user[:group] prog [args] */
669 /* Check for "host:...." line */
670 hostdelim = strrchr(arg, ':');
673 sep->se_local_hostname = xstrdup(arg);
676 arg = next_word(&cp);
678 /* Line has just "host:", change the
679 * default host for the following lines. */
680 free(default_local_hostname);
681 default_local_hostname = sep->se_local_hostname;
686 sep->se_local_hostname = xstrdup(default_local_hostname);
688 /* service socktype proto wait user[:group] prog [args] */
689 sep->se_service = xstrdup(arg);
690 /* socktype proto wait user[:group] prog [args] */
691 arg = next_word(&cp);
694 bb_error_msg("parse error on line %u, line is ignored",
696 free_servtab_strings(sep);
697 /* Just "goto more" can make sep to carry over e.g.
698 * "rpc"-ness (by having se_rpcver_lo != 0).
699 * We will be more paranoid: */
704 static int8_t SOCK_xxx[] ALIGN1 = {
706 SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
707 SOCK_SEQPACKET, SOCK_RAW
709 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
710 "stream""\0" "dgram""\0" "rdm""\0"
711 "seqpacket""\0" "raw""\0"
715 /* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
716 sep->se_proto = arg = xstrdup(next_word(&cp));
719 if (strcmp(arg, "unix") == 0) {
720 sep->se_family = AF_UNIX;
723 sep->se_family = AF_INET;
724 six = last_char_is(arg, '6');
726 #if ENABLE_FEATURE_IPV6
728 sep->se_family = AF_INET6;
730 bb_error_msg("%s: no support for IPv6", sep->se_proto);
734 if (strncmp(arg, "rpc/", 4) == 0) {
735 #if ENABLE_FEATURE_INETD_RPC
738 p = strchr(sep->se_service, '/');
740 bb_error_msg("no rpc version: '%s'", sep->se_service);
744 n = bb_strtou(p, &p, 10);
747 bb_error_msg("bad rpc version");
750 sep->se_rpcver_lo = sep->se_rpcver_hi = n;
753 n = bb_strtou(p, &p, 10);
754 if (n > INT_MAX || n < sep->se_rpcver_lo)
756 sep->se_rpcver_hi = n;
761 bb_error_msg("no support for rpc services");
765 /* we don't really need getprotobyname()! */
766 if (strcmp(arg, "tcp") == 0)
767 sep->se_proto_no = 6;
768 if (strcmp(arg, "udp") == 0)
769 sep->se_proto_no = 17;
772 if (!sep->se_proto_no) /* not tcp/udp?? */
776 /* [no]wait[.max] user[:group] prog [args] */
777 arg = next_word(&cp);
780 sep->se_max = max_concurrency;
781 p = strchr(arg, '.');
784 sep->se_max = bb_strtou(p, NULL, 10);
788 sep->se_wait = (strcmp(arg, "wait") == 0);
790 /* user[:group] prog [args] */
791 sep->se_user = xstrdup(next_word(&cp));
792 if (sep->se_user == NULL)
794 arg = strchr(sep->se_user, '.');
796 arg = strchr(sep->se_user, ':');
799 sep->se_group = xstrdup(arg);
803 sep->se_program = xstrdup(next_word(&cp));
804 if (sep->se_program == NULL)
806 #ifdef INETD_BUILTINS_ENABLED
807 /* sep->se_builtin = NULL; - done by new_servtab() */
808 if (strcmp(sep->se_program, "internal") == 0
809 && (sep->se_socktype == SOCK_STREAM
810 || sep->se_socktype == SOCK_DGRAM)
813 for (i = 0; i < ARRAY_SIZE(builtins); i++)
814 if (strcmp(builtins[i].bi_service, sep->se_service) == 0)
816 bb_error_msg("unknown internal service %s", sep->se_service);
819 sep->se_builtin = &builtins[i];
820 sep->se_wait = 0; /* = builtins[i].bi_wait; - always 0 */
824 while ((arg = next_word(&cp)) != NULL && argc < MAXARGV) {
825 sep->se_argv[argc++] = xstrdup(arg);
827 /* while (argc <= MAXARGV) */
828 /* sep->se_argv[argc++] = NULL; - done by new_servtab() */
831 * Now that we've processed the entire line, check if the hostname
832 * specifier was a comma separated list of hostnames. If so
833 * we'll make new entries for each address.
835 while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
836 nsep = dup_servtab(sep);
838 * NUL terminate the hostname field of the existing entry,
839 * and make a dup for the new entry.
842 nsep->se_local_hostname = xstrdup(hostdelim);
843 nsep->se_next = sep->se_next;
847 /* Was doing it here: */
848 /* DNS resolution, create copies for each IP address */
853 static servtab_t *insert_in_servlist(servtab_t *cp)
859 *sep = *cp; /* struct copy */
861 #if ENABLE_FEATURE_INETD_RPC
862 sep->se_rpcprog = -1;
864 block_CHLD_HUP_ALRM(&omask);
865 sep->se_next = serv_list;
867 unblock_sigs(&omask);
871 static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
873 if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
875 if (strcmp(old->se_service, new->se_service) != 0)
877 if (strcmp(old->se_proto, new->se_proto) != 0)
882 static void reread_config_file(int sig ATTRIBUTE_UNUSED)
884 servtab_t *sep, *cp, **sepp;
885 len_and_sockaddr *lsa;
890 if (!reopen_config_file())
892 for (sep = serv_list; sep; sep = sep->se_next)
899 cp = parse_one_line();
903 for (sep = serv_list; sep; sep = sep->se_next)
904 if (same_serv_addr_proto(sep, cp))
906 /* not an "equal" servtab */
907 sep = insert_in_servlist(cp);
913 block_CHLD_HUP_ALRM(&omask);
914 #if ENABLE_FEATURE_INETD_RPC
915 if (is_rpc_service(sep))
917 sep->se_rpcver_lo = cp->se_rpcver_lo;
918 sep->se_rpcver_hi = cp->se_rpcver_hi;
920 if (cp->se_wait == 0) {
921 /* New config says "nowait". If old one
922 * was "wait", we currently may be waiting
923 * for a child (and not accepting connects).
924 * Stop waiting, start listening again.
925 * (if it's not true, this op is harmless) */
926 add_fd_to_set(sep->se_fd);
928 sep->se_wait = cp->se_wait;
929 sep->se_max = cp->se_max;
930 /* string fields need more love - we don't want to leak them */
931 #define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
932 SWAP(char*, sep->se_user, cp->se_user);
933 SWAP(char*, sep->se_group, cp->se_group);
934 SWAP(char*, sep->se_program, cp->se_program);
935 for (i = 0; i < MAXARGV; i++)
936 SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
938 unblock_sigs(&omask);
939 free_servtab_strings(cp);
942 /* cp->string_fields are consumed by insert_in_servlist()
943 * or freed at this point, cp itself is not yet freed. */
946 /* create new len_and_sockaddr */
947 switch (sep->se_family) {
948 struct sockaddr_un *sun;
950 /* we have poor infrastructure for AF_UNIX... */
951 n = strlen(sep->se_service);
952 if (n > sizeof(sun->sun_path) - 1)
953 n = sizeof(sun->sun_path) - 1;
954 lsa = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_un));
955 lsa->len = sizeof(struct sockaddr_un);
956 sun = (struct sockaddr_un*)&lsa->u.sa;
957 sun->sun_family = AF_UNIX;
958 strncpy(sun->sun_path, sep->se_service, n);
961 default: /* case AF_INET, case AF_INET6 */
962 n = bb_strtou(sep->se_service, NULL, 10);
963 #if ENABLE_FEATURE_INETD_RPC
964 if (is_rpc_service(sep)) {
966 if (errno) { /* se_service is not numeric */
967 struct rpcent *rp = getrpcbyname(sep->se_service);
969 bb_error_msg("%s: unknown rpc service", sep->se_service);
972 sep->se_rpcprog = rp->r_number;
974 if (sep->se_fd == -1)
975 prepare_socket_fd(sep);
976 if (sep->se_fd != -1)
981 /* what port to listen on? */
983 if (errno || n > 0xffff) { /* se_service is not numeric */
986 /* can result only in "tcp" or "udp": */
987 safe_strncpy(protoname, sep->se_proto, 4);
988 sp = getservbyname(sep->se_service, protoname);
990 bb_error_msg("%s/%s: unknown service",
991 sep->se_service, sep->se_proto);
996 if (LONE_CHAR(sep->se_local_hostname, '*')) {
997 lsa = xzalloc_lsa(sep->se_family);
998 set_nport(lsa, port);
1000 lsa = host_and_af2sockaddr(sep->se_local_hostname,
1001 ntohs(port), sep->se_family);
1003 bb_error_msg("%s/%s: unknown host '%s'",
1004 sep->se_service, sep->se_proto,
1005 sep->se_local_hostname);
1010 } /* end of "switch (sep->se_family)" */
1012 /* did lsa change? Then close/open */
1013 if (sep->se_lsa == NULL
1014 || lsa->len != sep->se_lsa->len
1015 || memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
1017 remove_fd_from_set(sep->se_fd);
1018 maybe_close(sep->se_fd);
1025 if (sep->se_fd == -1)
1026 prepare_socket_fd(sep);
1031 } /* end of "while (1) parse lines" */
1032 close_config_file();
1034 /* Purge anything not looked at above - these are stale entries,
1035 * new config file doesnt have them. */
1036 block_CHLD_HUP_ALRM(&omask);
1038 while ((sep = *sepp)) {
1039 if (sep->se_checked) {
1040 sepp = &sep->se_next;
1043 *sepp = sep->se_next;
1044 remove_fd_from_set(sep->se_fd);
1045 maybe_close(sep->se_fd);
1046 #if ENABLE_FEATURE_INETD_RPC
1047 if (is_rpc_service(sep))
1048 unregister_rpc(sep);
1050 if (sep->se_family == AF_UNIX)
1051 unlink(sep->se_service);
1052 free_servtab_strings(sep);
1055 unblock_sigs(&omask);
1058 static void reap_child(int sig ATTRIBUTE_UNUSED)
1063 int save_errno = errno;
1066 pid = wait_any_nohang(&status);
1069 for (sep = serv_list; sep; sep = sep->se_next)
1070 if (sep->se_wait == pid) {
1071 /* One of our "wait" services */
1072 if (WIFEXITED(status) && WEXITSTATUS(status))
1073 bb_error_msg("%s: exit status 0x%x",
1074 sep->se_program, WEXITSTATUS(status));
1075 else if (WIFSIGNALED(status))
1076 bb_error_msg("%s: exit signal 0x%x",
1077 sep->se_program, WTERMSIG(status));
1079 add_fd_to_set(sep->se_fd);
1085 static void retry_network_setup(int sig ATTRIBUTE_UNUSED)
1090 for (sep = serv_list; sep; sep = sep->se_next) {
1091 if (sep->se_fd == -1) {
1092 prepare_socket_fd(sep);
1093 #if ENABLE_FEATURE_INETD_RPC
1094 if (sep->se_fd != -1 && is_rpc_service(sep))
1101 static void clean_up_and_exit(int sig ATTRIBUTE_UNUSED)
1105 /* XXX signal race walking sep list */
1106 for (sep = serv_list; sep; sep = sep->se_next) {
1107 if (sep->se_fd == -1)
1110 switch (sep->se_family) {
1112 unlink(sep->se_service);
1114 default: /* case AF_INET, AF_INET6 */
1115 #if ENABLE_FEATURE_INETD_RPC
1116 if (sep->se_wait == 1 && is_rpc_service(sep))
1117 unregister_rpc(sep); /* XXX signal race */
1121 if (ENABLE_FEATURE_CLEAN_UP)
1124 remove_pidfile(_PATH_INETDPID);
1128 int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1129 int inetd_main(int argc, char **argv)
1131 struct sigaction sa, saved_pipe_handler;
1132 servtab_t *sep, *sep2;
1134 struct group *grp = grp; /* for compiler */
1141 real_uid = getuid();
1142 if (real_uid != 0) /* run by non-root user */
1143 config_filename = NULL;
1145 opt_complementary = "R+:q+"; /* -q N, -R N */
1146 opt = getopt32(argv, "R:feq:", &max_concurrency, &global_queuelen);
1150 config_filename = argv[0];
1151 if (config_filename == NULL)
1152 bb_error_msg_and_die("non-root must specify config file");
1154 bb_daemonize_or_rexec(0, argv - optind);
1156 bb_sanitize_stdio();
1158 openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
1159 logmode = LOGMODE_SYSLOG;
1162 if (real_uid == 0) {
1163 /* run by root, ensure groups vector gets trashed */
1164 gid_t gid = getgid();
1168 write_pidfile(_PATH_INETDPID);
1170 /* never fails under Linux (except if you pass it bad arguments) */
1171 getrlimit(RLIMIT_NOFILE, &rlim_ofile);
1172 rlim_ofile_cur = rlim_ofile.rlim_cur;
1173 if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
1174 rlim_ofile_cur = OPEN_MAX;
1176 memset(&sa, 0, sizeof(sa));
1177 /*sigemptyset(&sa.sa_mask); - memset did it */
1178 sigaddset(&sa.sa_mask, SIGALRM);
1179 sigaddset(&sa.sa_mask, SIGCHLD);
1180 sigaddset(&sa.sa_mask, SIGHUP);
1181 sa.sa_handler = retry_network_setup;
1182 sigaction(SIGALRM, &sa, NULL);
1183 sa.sa_handler = reread_config_file;
1184 sigaction(SIGHUP, &sa, NULL);
1185 sa.sa_handler = reap_child;
1186 sigaction(SIGCHLD, &sa, NULL);
1187 sa.sa_handler = clean_up_and_exit;
1188 sigaction(SIGTERM, &sa, NULL);
1189 sa.sa_handler = clean_up_and_exit;
1190 sigaction(SIGINT, &sa, NULL);
1191 sa.sa_handler = SIG_IGN;
1192 sigaction(SIGPIPE, &sa, &saved_pipe_handler);
1194 reread_config_file(SIGHUP); /* load config from file */
1198 int ctrl, accepted_fd;
1202 recalculate_maxsock();
1204 readable = allsock; /* struct copy */
1205 /* if there are no fds to wait on, we will block
1206 * until signal wakes us up */
1207 ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
1208 if (ready_fd_cnt < 0) {
1209 if (errno != EINTR) {
1210 bb_perror_msg("select");
1216 for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
1217 if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1223 if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
1224 ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
1227 bb_perror_msg("accept (for %s)", sep->se_service);
1232 block_CHLD_HUP_ALRM(&omask);
1234 #ifdef INETD_BUILTINS_ENABLED
1235 /* do we need to fork? */
1236 if (sep->se_builtin == NULL
1237 || (sep->se_socktype == SOCK_STREAM
1238 && sep->se_builtin->bi_fork))
1241 if (sep->se_max != 0) {
1242 if (++sep->se_count == 1)
1243 sep->se_time = monotonic_sec();
1244 else if (sep->se_count >= sep->se_max) {
1245 unsigned now = monotonic_sec();
1246 /* did we accumulate se_max connects too quickly? */
1247 if (now - sep->se_time <= CNT_INTERVAL) {
1248 bb_error_msg("%s/%s: too many connections, pausing",
1249 sep->se_service, sep->se_proto);
1250 remove_fd_from_set(sep->se_fd);
1254 rearm_alarm(); /* will revive it in RETRYTIME sec */
1255 unblock_sigs(&omask);
1256 maybe_close(accepted_fd);
1257 continue; /* -> check next fd in fd set */
1262 /* on NOMMU, streamed echo, chargen and discard
1263 * builtins wouldn't work, but they are
1264 * not allowed on NOMMU (ifdefed out) */
1265 #ifdef INETD_BUILTINS_ENABLED
1266 if (BB_MMU && sep->se_builtin)
1272 if (pid < 0) { /* fork error */
1273 bb_perror_msg("fork");
1275 unblock_sigs(&omask);
1276 maybe_close(accepted_fd);
1277 continue; /* -> check next fd in fd set */
1280 pid--; /* -1: "we did fork and we are child" */
1282 /* if pid == 0 here, we never forked */
1284 if (pid > 0) { /* parent */
1287 remove_fd_from_set(sep->se_fd);
1288 /* we passed listening socket to child,
1289 * will wait for child to terminate */
1291 unblock_sigs(&omask);
1292 maybe_close(accepted_fd);
1293 continue; /* -> check next fd in fd set */
1296 /* we are either child or didn't fork at all */
1297 #ifdef INETD_BUILTINS_ENABLED
1298 if (sep->se_builtin) {
1299 if (pid) { /* "pid" is -1: we did fork */
1300 close(sep->se_fd); /* listening socket */
1301 logmode = 0; /* make xwrite etc silent */
1303 unblock_sigs(&omask);
1304 if (sep->se_socktype == SOCK_STREAM)
1305 sep->se_builtin->bi_stream_fn(ctrl, sep);
1307 sep->se_builtin->bi_dgram_fn(ctrl, sep);
1308 if (pid) /* we did fork */
1310 maybe_close(accepted_fd);
1311 continue; /* -> check next fd in fd set */
1314 /* child. prepare env and exec program */
1316 pwd = getpwnam(sep->se_user);
1318 bb_error_msg("%s: no such user", sep->se_user);
1321 if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1322 bb_error_msg("%s: no such group", sep->se_group);
1325 if (real_uid != 0 && real_uid != pwd->pw_uid) {
1326 /* a user running private inetd */
1327 bb_error_msg("non-root must run services as himself");
1332 pwd->pw_gid = grp->gr_gid;
1333 xsetgid(pwd->pw_gid);
1334 initgroups(pwd->pw_name, pwd->pw_gid);
1335 xsetuid(pwd->pw_uid);
1336 } else if (sep->se_group) {
1337 xsetgid(grp->gr_gid);
1338 setgroups(1, &grp->gr_gid);
1340 if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1341 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1342 bb_perror_msg("setrlimit");
1347 /* NB: among others, this loop closes listening socket
1348 * for nowait stream children */
1349 for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
1350 maybe_close(sep2->se_fd);
1351 sigaction(SIGPIPE, &saved_pipe_handler, NULL);
1352 unblock_sigs(&omask);
1353 BB_EXECVP(sep->se_program, sep->se_argv);
1354 bb_perror_msg("exec %s", sep->se_program);
1356 /* eat packet in udp case */
1357 if (sep->se_socktype != SOCK_STREAM)
1358 recv(0, line, LINE_SIZE, MSG_DONTWAIT);
1360 } /* for (sep = servtab...) */
1365 * Internet services provided internally by inetd:
1367 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1368 /* Echo service -- echo data back. */
1370 static void echo_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1374 ssize_t sz = safe_read(s, line, LINE_SIZE);
1377 xwrite(s, line, sz);
1380 static const char *const args[] = { "cat", NULL };
1381 BB_EXECVP("cat", (char**)args);
1385 static void echo_dg(int s, servtab_t *sep)
1387 enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
1388 char *buf = xmalloc(BUFSIZE); /* too big for stack */
1390 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1392 lsa->len = sep->se_lsa->len;
1393 /* dgram builtins are non-forking - DONT BLOCK! */
1394 sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
1396 sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
1399 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1402 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1403 /* Discard service -- ignore data. MMU arches only. */
1405 static void discard_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1407 while (safe_read(s, line, LINE_SIZE) > 0)
1411 static void discard_dg(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1413 /* dgram builtins are non-forking - DONT BLOCK! */
1414 recv(s, line, LINE_SIZE, MSG_DONTWAIT);
1416 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1419 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1421 static void initring(void)
1426 for (i = 0; i <= 128; ++i)
1430 /* Character generator. MMU arches only. */
1432 static void chargen_stream(int s, servtab_t *sep)
1436 char text[LINESIZ + 2];
1443 text[LINESIZ] = '\r';
1444 text[LINESIZ + 1] = '\n';
1449 memmove(text, rs, LINESIZ);
1451 memmove(text, rs, len);
1452 memmove(text + len, ring, LINESIZ - len);
1454 if (++rs == endring)
1456 xwrite(s, text, sizeof(text));
1460 static void chargen_dg(int s, servtab_t *sep)
1463 char text[LINESIZ + 2];
1464 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1466 /* Eat UDP packet which started it all */
1467 /* dgram builtins are non-forking - DONT BLOCK! */
1468 lsa->len = sep->se_lsa->len;
1469 if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1477 len = endring - ringpos;
1479 memmove(text, ringpos, LINESIZ);
1481 memmove(text, ringpos, len);
1482 memmove(text + len, ring, LINESIZ - len);
1484 if (++ringpos == endring)
1486 text[LINESIZ] = '\r';
1487 text[LINESIZ + 1] = '\n';
1488 sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
1490 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1493 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1495 * Return a machine readable date and time, in the form of the
1496 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
1497 * returns the number of seconds since midnight, Jan 1, 1970,
1498 * we must add 2208988800 seconds to this figure to make up for
1499 * some seventy years Bell Labs was asleep.
1501 static unsigned machtime(void)
1505 gettimeofday(&tv, NULL);
1506 return htonl((uint32_t)(tv.tv_sec + 2208988800));
1509 static void machtime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1513 result = machtime();
1514 full_write(s, &result, sizeof(result));
1516 static void machtime_dg(int s, servtab_t *sep)
1519 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1521 lsa->len = sep->se_lsa->len;
1522 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1525 result = machtime();
1526 sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
1528 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1531 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1532 /* Return human-readable time of day */
1534 static void daytime_stream(int s, servtab_t *sep ATTRIBUTE_UNUSED)
1539 fdprintf(s, "%.24s\r\n", ctime(&t));
1541 static void daytime_dg(int s, servtab_t *sep)
1544 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1546 lsa->len = sep->se_lsa->len;
1547 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1551 sprintf(line, "%.24s\r\n", ctime(&t));
1552 sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
1554 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */