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> */
6 /* IPv6 support, many bug fixes by Denys Vlasenko (c) 2008 */
7 /*
8 * Copyright (c) 1983,1991 The Regents of the University of California.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 */
39
40 /* Inetd - Internet super-server
41 *
42 * This program invokes configured services when a connection
43 * from a peer is established or a datagram arrives.
44 * Connection-oriented services are invoked each time a
45 * connection is made, by creating a process. This process
46 * is passed the connection as file descriptor 0 and is
47 * expected to do a getpeername to find out peer's host
48 * and port.
49 * Datagram oriented services are invoked when a datagram
50 * arrives; a process is created and passed a pending message
51 * on file descriptor 0. peer's address can be obtained
52 * using recvfrom.
53 *
54 * Inetd uses a configuration file which is read at startup
55 * and, possibly, at some later time in response to a hangup signal.
56 * The configuration file is "free format" with fields given in the
57 * order shown below. Continuation lines for an entry must begin with
58 * a space or tab. All fields must be present in each entry.
59 *
60 * service_name must be in /etc/services
61 * socket_type stream/dgram/raw/rdm/seqpacket
62 * protocol must be in /etc/protocols
63 * (usually "tcp" or "udp")
64 * wait/nowait[.max] single-threaded/multi-threaded, max #
65 * user[.group] or user[:group] user/group to run daemon as
66 * server_program full path name
67 * server_program_arguments maximum of MAXARGS (20)
68 *
69 * For RPC services
70 * service_name/version must be in /etc/rpc
71 * socket_type stream/dgram/raw/rdm/seqpacket
72 * rpc/protocol "rpc/tcp" etc
73 * wait/nowait[.max] single-threaded/multi-threaded
74 * user[.group] or user[:group] user to run daemon as
75 * server_program full path name
76 * server_program_arguments maximum of MAXARGS (20)
77 *
78 * For non-RPC services, the "service name" can be of the form
79 * hostaddress:servicename, in which case the hostaddress is used
80 * as the host portion of the address to listen on. If hostaddress
81 * consists of a single '*' character, INADDR_ANY is used.
82 *
83 * A line can also consist of just
84 * hostaddress:
85 * where hostaddress is as in the preceding paragraph. Such a line must
86 * have no further fields; the specified hostaddress is remembered and
87 * used for all further lines that have no hostaddress specified,
88 * until the next such line (or EOF). (This is why * is provided to
89 * allow explicit specification of INADDR_ANY.) A line
90 * *:
91 * is implicitly in effect at the beginning of the file.
92 *
93 * The hostaddress specifier may (and often will) contain dots;
94 * the service name must not.
95 *
96 * For RPC services, host-address specifiers are accepted and will
97 * work to some extent; however, because of limitations in the
98 * portmapper interface, it will not work to try to give more than
99 * one line for any given RPC service, even if the host-address
100 * specifiers are different.
101 *
102 * Comment lines are indicated by a '#' in column 1.
103 */
104
105 /* inetd rules for passing file descriptors to children
106 * (http://www.freebsd.org/cgi/man.cgi?query=inetd):
107 *
108 * The wait/nowait entry specifies whether the server that is invoked by
109 * inetd will take over the socket associated with the service access point,
110 * and thus whether inetd should wait for the server to exit before listen-
111 * ing for new service requests. Datagram servers must use "wait", as
112 * they are always invoked with the original datagram socket bound to the
113 * specified service address. These servers must read at least one datagram
114 * from the socket before exiting. If a datagram server connects to its
115 * peer, freeing the socket so inetd can receive further messages on the
116 * socket, it is said to be a "multi-threaded" server; it should read one
117 * datagram from the socket and create a new socket connected to the peer.
118 * It should fork, and the parent should then exit to allow inetd to check
119 * for new service requests to spawn new servers. Datagram servers which
120 * process all incoming datagrams on a socket and eventually time out are
121 * said to be "single-threaded". The comsat(8), biff(1) and talkd(8)
122 * utilities are both examples of the latter type of datagram server. The
123 * tftpd(8) utility is an example of a multi-threaded datagram server.
124 *
125 * Servers using stream sockets generally are multi-threaded and use the
126 * "nowait" entry. Connection requests for these services are accepted by
127 * inetd, and the server is given only the newly-accepted socket connected
128 * to a client of the service. Most stream-based services operate in this
129 * manner. Stream-based servers that use "wait" are started with the lis-
130 * tening service socket, and must accept at least one connection request
131 * before exiting. Such a server would normally accept and process incoming
132 * connection requests until a timeout.
133 */
134
135 /* Despite of above doc saying that dgram services must use "wait",
136 * "udp nowait" servers are implemented in busyboxed inetd.
137 * IPv6 addresses are also implemented. However, they may look ugly -
138 * ":::service..." means "address '::' (IPv6 wildcard addr)":"service"...
139 * You have to put "tcp6"/"udp6" in protocol field to select IPv6.
140 */
141
142 /* Here's the scoop concerning the user[:group] feature:
143 * 1) group is not specified:
144 * a) user = root: NO setuid() or setgid() is done
145 * b) other: initgroups(name, primary group)
146 * setgid(primary group as found in passwd)
147 * setuid()
148 * 2) group is specified:
149 * a) user = root: setgid(specified group)
150 * NO initgroups()
151 * NO setuid()
152 * b) other: initgroups(name, specified group)
153 * setgid(specified group)
154 * setuid()
155 */
156 //config:config INETD
157 //config: bool "inetd (18 kb)"
158 //config: default y
159 //config: select FEATURE_SYSLOG
160 //config: help
161 //config: Internet superserver daemon
162 //config:
163 //config:config FEATURE_INETD_SUPPORT_BUILTIN_ECHO
164 //config: bool "Support echo service on port 7"
165 //config: default y
166 //config: depends on INETD
167 //config: help
168 //config: Internal service which echoes data back.
169 //config: Activated by configuration lines like these:
170 //config: echo stream tcp nowait root internal
171 //config: echo dgram udp wait root internal
172 //config:
173 //config:config FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
174 //config: bool "Support discard service on port 8"
175 //config: default y
176 //config: depends on INETD
177 //config: help
178 //config: Internal service which discards all input.
179 //config: Activated by configuration lines like these:
180 //config: discard stream tcp nowait root internal
181 //config: discard dgram udp wait root internal
182 //config:
183 //config:config FEATURE_INETD_SUPPORT_BUILTIN_TIME
184 //config: bool "Support time service on port 37"
185 //config: default y
186 //config: depends on INETD
187 //config: help
188 //config: Internal service which returns big-endian 32-bit number
189 //config: of seconds passed since 1900-01-01. The number wraps around
190 //config: on overflow.
191 //config: Activated by configuration lines like these:
192 //config: time stream tcp nowait root internal
193 //config: time dgram udp wait root internal
194 //config:
195 //config:config FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
196 //config: bool "Support daytime service on port 13"
197 //config: default y
198 //config: depends on INETD
199 //config: help
200 //config: Internal service which returns human-readable time.
201 //config: Activated by configuration lines like these:
202 //config: daytime stream tcp nowait root internal
203 //config: daytime dgram udp wait root internal
204 //config:
205 //config:config FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
206 //config: bool "Support chargen service on port 19"
207 //config: default y
208 //config: depends on INETD
209 //config: help
210 //config: Internal service which generates endless stream
211 //config: of all ASCII chars beetween space and char 126.
212 //config: Activated by configuration lines like these:
213 //config: chargen stream tcp nowait root internal
214 //config: chargen dgram udp wait root internal
215 //config:
216 //config:config FEATURE_INETD_RPC
217 //config: bool "Support RPC services"
218 //config: default n # very rarely used, and needs Sun RPC support in libc
219 //config: depends on INETD
220 //config: help
221 //config: Support Sun-RPC based services
222
223 //applet:IF_INETD(APPLET(inetd, BB_DIR_USR_SBIN, BB_SUID_DROP))
224
225 //kbuild:lib-$(CONFIG_INETD) += inetd.o
226
227 //usage:#define inetd_trivial_usage
228 //usage: "[-fe] [-q N] [-R N] [CONFFILE]"
229 //usage:#define inetd_full_usage "\n\n"
230 //usage: "Listen for network connections and launch programs\n"
231 //usage: "\n -f Run in foreground"
232 //usage: "\n -e Log to stderr"
233 //usage: "\n -q N Socket listen queue (default 128)"
234 //usage: "\n -R N Pause services after N connects/min"
235 //usage: "\n (default 0 - disabled)"
236 //usage: "\n Default CONFFILE is /etc/inetd.conf"
237
238 #include <syslog.h>
239 #include <sys/resource.h> /* setrlimit */
240 #include <sys/socket.h> /* un.h may need this */
241 #include <sys/un.h>
242
243 #include "libbb.h"
244 #include "common_bufsiz.h"
245
246 #if ENABLE_FEATURE_INETD_RPC
247 # if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
248 # warning "You probably need to build uClibc with UCLIBC_HAS_RPC for NFS support"
249 /* not #error, since user may be using e.g. libtirpc instead.
250 * This might work:
251 * CONFIG_EXTRA_CFLAGS="-I/usr/include/tirpc"
252 * CONFIG_EXTRA_LDLIBS="tirpc"
253 */
254 # endif
255 # include <rpc/rpc.h>
256 # include <rpc/pmap_clnt.h>
257 #endif
258
259 #if !BB_MMU
260 /* stream version of chargen is forking but not execing,
261 * can't do that (easily) on NOMMU */
262 #undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
263 #define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
264 #endif
265
266 #define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
267 #define RETRYTIME 60 /* retry after bind or server fail */
268
269 // TODO: explain, or get rid of setrlimit games
270
271 #ifndef RLIMIT_NOFILE
272 #define RLIMIT_NOFILE RLIMIT_OFILE
273 #endif
274
275 #ifndef OPEN_MAX
276 #define OPEN_MAX 64
277 #endif
278
279 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
280 #define FD_MARGIN 8
281
282 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
283 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
284 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
285 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
286 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
287 # define INETD_BUILTINS_ENABLED
288 #endif
289
290 typedef struct servtab_t {
291 /* The most frequently referenced one: */
292 int se_fd; /* open descriptor */
293 /* NB: 'biggest fields last' saves on code size (~250 bytes) */
294 /* [addr:]service socktype proto wait user[:group] prog [args] */
295 char *se_local_hostname; /* addr to listen on */
296 char *se_service; /* "80" or "www" or "mount/2[-3]" */
297 /* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
298 char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
299 #if ENABLE_FEATURE_INETD_RPC
300 int se_rpcprog; /* rpc program number */
301 int se_rpcver_lo; /* rpc program lowest version */
302 int se_rpcver_hi; /* rpc program highest version */
303 #define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
304 #else
305 #define is_rpc_service(sep) 0
306 #endif
307 pid_t se_wait; /* 0:"nowait", 1:"wait", >1:"wait" */
308 /* and waiting for this pid */
309 socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
310 family_t se_family; /* AF_UNIX/INET[6] */
311 /* se_proto_no is used by RPC code only... hmm */
312 smallint se_proto_no; /* IPPROTO_TCP/UDP, n/a for AF_UNIX */
313 smallint se_checked; /* looked at during merge */
314 unsigned se_max; /* allowed instances per minute */
315 unsigned se_count; /* number started since se_time */
316 unsigned se_time; /* when we started counting */
317 char *se_user; /* user name to run as */
318 char *se_group; /* group name to run as, can be NULL */
319 #ifdef INETD_BUILTINS_ENABLED
320 const struct builtin *se_builtin; /* if built-in, description */
321 #endif
322 struct servtab_t *se_next;
323 len_and_sockaddr *se_lsa;
324 char *se_program; /* server program */
325 #define MAXARGV 20
326 char *se_argv[MAXARGV + 1]; /* program arguments */
327 } servtab_t;
328
329 #ifdef INETD_BUILTINS_ENABLED
330 /* Echo received data */
331 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
332 static void FAST_FUNC echo_stream(int, servtab_t *);
333 static void FAST_FUNC echo_dg(int, servtab_t *);
334 #endif
335 /* Internet /dev/null */
336 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
337 static void FAST_FUNC discard_stream(int, servtab_t *);
338 static void FAST_FUNC discard_dg(int, servtab_t *);
339 #endif
340 /* Return 32 bit time since 1900 */
341 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
342 static void FAST_FUNC machtime_stream(int, servtab_t *);
343 static void FAST_FUNC machtime_dg(int, servtab_t *);
344 #endif
345 /* Return human-readable time */
346 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
347 static void FAST_FUNC daytime_stream(int, servtab_t *);
348 static void FAST_FUNC daytime_dg(int, servtab_t *);
349 #endif
350 /* Familiar character generator */
351 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
352 static void FAST_FUNC chargen_stream(int, servtab_t *);
353 static void FAST_FUNC chargen_dg(int, servtab_t *);
354 #endif
355
356 struct builtin {
357 /* NB: not necessarily NUL terminated */
358 char bi_service7[7]; /* internally provided service name */
359 uint8_t bi_fork; /* 1 if stream fn should run in child */
360 void (*bi_stream_fn)(int, servtab_t *) FAST_FUNC;
361 void (*bi_dgram_fn)(int, servtab_t *) FAST_FUNC;
362 };
363
364 static const struct builtin builtins[] ALIGN_PTR = {
365 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
366 { "echo", 1, echo_stream, echo_dg },
367 #endif
368 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
369 { "discard", 1, discard_stream, discard_dg },
370 #endif
371 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
372 { "chargen", 1, chargen_stream, chargen_dg },
373 #endif
374 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
375 { "time", 0, machtime_stream, machtime_dg },
376 #endif
377 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
378 { "daytime", 0, daytime_stream, daytime_dg },
379 #endif
380 };
381 #endif /* INETD_BUILTINS_ENABLED */
382
383 struct globals {
384 rlim_t rlim_ofile_cur;
385 struct rlimit rlim_ofile;
386 servtab_t *serv_list;
387 int global_queuelen;
388 int maxsock; /* max fd# in allsock, -1: unknown */
389 /* whenever maxsock grows, prev_maxsock is set to new maxsock,
390 * but if maxsock is set to -1, prev_maxsock is not changed */
391 int prev_maxsock;
392 unsigned max_concurrency;
393 smallint alarm_armed;
394 uid_t real_uid; /* user ID who ran us */
395 const char *config_filename;
396 parser_t *parser;
397 char *default_local_hostname;
398 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
399 char *end_ring;
400 char *ring_pos;
401 char ring[128];
402 #endif
403 fd_set allsock;
404 /* Used in next_line(), and as scratch read buffer */
405 char line[256]; /* _at least_ 256, see LINE_SIZE */
406 } FIX_ALIASING;
407 #define G (*(struct globals*)bb_common_bufsiz1)
408 enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
409 #define rlim_ofile_cur (G.rlim_ofile_cur )
410 #define rlim_ofile (G.rlim_ofile )
411 #define serv_list (G.serv_list )
412 #define global_queuelen (G.global_queuelen)
413 #define maxsock (G.maxsock )
414 #define prev_maxsock (G.prev_maxsock )
415 #define max_concurrency (G.max_concurrency)
416 #define alarm_armed (G.alarm_armed )
417 #define real_uid (G.real_uid )
418 #define config_filename (G.config_filename)
419 #define parser (G.parser )
420 #define default_local_hostname (G.default_local_hostname)
421 #define first_ps_byte (G.first_ps_byte )
422 #define last_ps_byte (G.last_ps_byte )
423 #define end_ring (G.end_ring )
424 #define ring_pos (G.ring_pos )
425 #define ring (G.ring )
426 #define allsock (G.allsock )
427 #define line (G.line )
428 #define INIT_G() do { \
429 setup_common_bufsiz(); \
430 BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
431 rlim_ofile_cur = OPEN_MAX; \
432 global_queuelen = 128; \
433 config_filename = "/etc/inetd.conf"; \
434 } while (0)
435
436 #if 1
437 # define dbg(...) ((void)0)
438 #else
439 # define dbg(...) \
440 do { \
441 int dbg_fd = open("inetd_debug.log", O_WRONLY | O_CREAT | O_APPEND, 0666); \
442 if (dbg_fd >= 0) { \
443 fdprintf(dbg_fd, "%d: ", getpid()); \
444 fdprintf(dbg_fd, __VA_ARGS__); \
445 close(dbg_fd); \
446 } \
447 } while (0)
448 #endif
449
maybe_close(int fd)450 static void maybe_close(int fd)
451 {
452 if (fd >= 0) {
453 close(fd);
454 dbg("closed fd:%d\n", fd);
455 }
456 }
457
458 // TODO: move to libbb?
xzalloc_lsa(int family)459 static len_and_sockaddr *xzalloc_lsa(int family)
460 {
461 len_and_sockaddr *lsa;
462 int sz;
463
464 sz = sizeof(struct sockaddr_in);
465 if (family == AF_UNIX)
466 sz = sizeof(struct sockaddr_un);
467 #if ENABLE_FEATURE_IPV6
468 if (family == AF_INET6)
469 sz = sizeof(struct sockaddr_in6);
470 #endif
471 lsa = xzalloc(LSA_LEN_SIZE + sz);
472 lsa->len = sz;
473 lsa->u.sa.sa_family = family;
474 return lsa;
475 }
476
rearm_alarm(void)477 static void rearm_alarm(void)
478 {
479 if (!alarm_armed) {
480 alarm_armed = 1;
481 alarm(RETRYTIME);
482 }
483 }
484
block_CHLD_HUP_ALRM(sigset_t * m)485 static void block_CHLD_HUP_ALRM(sigset_t *m)
486 {
487 sigemptyset(m);
488 sigaddset(m, SIGCHLD);
489 sigaddset(m, SIGHUP);
490 sigaddset(m, SIGALRM);
491 sigprocmask2(SIG_BLOCK, m); /* old sigmask is stored in m */
492 }
493
restore_sigmask(sigset_t * m)494 static void restore_sigmask(sigset_t *m)
495 {
496 sigprocmask(SIG_SETMASK, m, NULL);
497 }
498
499 #if ENABLE_FEATURE_INETD_RPC
register_rpc(servtab_t * sep)500 static void register_rpc(servtab_t *sep)
501 {
502 int n;
503 struct sockaddr_in ir_sin;
504
505 if (bb_getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, sizeof(ir_sin)) < 0) {
506 //TODO: verify that such failure is even possible in Linux kernel
507 bb_simple_perror_msg("getsockname");
508 return;
509 }
510
511 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
512 pmap_unset(sep->se_rpcprog, n);
513 if (!pmap_set(sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port)))
514 bb_perror_msg("%s %s: pmap_set(%u,%u,%u,%u)",
515 sep->se_service, sep->se_proto,
516 sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port));
517 }
518 }
519
unregister_rpc(servtab_t * sep)520 static void unregister_rpc(servtab_t *sep)
521 {
522 int n;
523
524 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
525 if (!pmap_unset(sep->se_rpcprog, n))
526 bb_perror_msg("pmap_unset(%u,%u)", sep->se_rpcprog, n);
527 }
528 }
529 #endif /* FEATURE_INETD_RPC */
530
bump_nofile(void)531 static void bump_nofile(void)
532 {
533 enum { FD_CHUNK = 32 };
534 struct rlimit rl;
535
536 /* Never fails under Linux (except if you pass it bad arguments) */
537 getrlimit(RLIMIT_NOFILE, &rl);
538 rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
539 rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
540 if (rl.rlim_cur <= rlim_ofile_cur) {
541 bb_error_msg("can't extend file limit, max = %d",
542 (int) rl.rlim_cur);
543 return;
544 }
545
546 if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
547 bb_simple_perror_msg("setrlimit");
548 return;
549 }
550
551 rlim_ofile_cur = rl.rlim_cur;
552 }
553
remove_fd_from_set(int fd)554 static void remove_fd_from_set(int fd)
555 {
556 if (fd >= 0) {
557 FD_CLR(fd, &allsock);
558 dbg("stopped listening on fd:%d\n", fd);
559 maxsock = -1;
560 dbg("maxsock:%d\n", maxsock);
561 }
562 }
563
add_fd_to_set(int fd)564 static void add_fd_to_set(int fd)
565 {
566 if (fd >= 0) {
567 FD_SET(fd, &allsock);
568 dbg("started listening on fd:%d\n", fd);
569 if (maxsock >= 0 && fd > maxsock) {
570 prev_maxsock = maxsock = fd;
571 dbg("maxsock:%d\n", maxsock);
572 if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
573 bump_nofile();
574 }
575 }
576 }
577
recalculate_maxsock(void)578 static void recalculate_maxsock(void)
579 {
580 int fd = 0;
581
582 /* We may have no services, in this case maxsock should still be >= 0
583 * (code elsewhere is not happy with maxsock == -1) */
584 maxsock = 0;
585 while (fd <= prev_maxsock) {
586 if (FD_ISSET(fd, &allsock))
587 maxsock = fd;
588 fd++;
589 }
590 dbg("recalculated maxsock:%d\n", maxsock);
591 prev_maxsock = maxsock;
592 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
593 bump_nofile();
594 }
595
prepare_socket_fd(servtab_t * sep)596 static void prepare_socket_fd(servtab_t *sep)
597 {
598 int r, fd;
599
600 fd = socket(sep->se_family, sep->se_socktype, 0);
601 if (fd < 0) {
602 bb_simple_perror_msg("socket");
603 return;
604 }
605 setsockopt_reuseaddr(fd);
606
607 #if ENABLE_FEATURE_INETD_RPC
608 if (is_rpc_service(sep)) {
609 struct passwd *pwd;
610
611 /* zero out the port for all RPC services; let bind()
612 * find one. */
613 set_nport(&sep->se_lsa->u.sa, 0);
614
615 /* for RPC services, attempt to use a reserved port
616 * if they are going to be running as root. */
617 if (real_uid == 0 && sep->se_family == AF_INET
618 && (pwd = getpwnam(sep->se_user)) != NULL
619 && pwd->pw_uid == 0
620 ) {
621 r = bindresvport(fd, &sep->se_lsa->u.sin);
622 } else {
623 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
624 }
625 if (r == 0) {
626 int saveerrno = errno;
627 /* update lsa with port# */
628 getsockname(fd, &sep->se_lsa->u.sa, &sep->se_lsa->len);
629 errno = saveerrno;
630 }
631 } else
632 #endif
633 {
634 if (sep->se_family == AF_UNIX) {
635 struct sockaddr_un *sun;
636 sun = (struct sockaddr_un*)&(sep->se_lsa->u.sa);
637 unlink(sun->sun_path);
638 }
639 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
640 }
641 if (r < 0) {
642 bb_perror_msg("%s/%s: bind",
643 sep->se_service, sep->se_proto);
644 close(fd);
645 rearm_alarm();
646 return;
647 }
648
649 if (sep->se_socktype == SOCK_STREAM) {
650 listen(fd, global_queuelen);
651 dbg("new sep->se_fd:%d (stream)\n", fd);
652 } else {
653 dbg("new sep->se_fd:%d (!stream)\n", fd);
654 }
655
656 add_fd_to_set(fd);
657 sep->se_fd = fd;
658 }
659
reopen_config_file(void)660 static int reopen_config_file(void)
661 {
662 free(default_local_hostname);
663 default_local_hostname = xstrdup("*");
664 if (parser != NULL)
665 config_close(parser);
666 parser = config_open(config_filename);
667 return (parser != NULL);
668 }
669
close_config_file(void)670 static void close_config_file(void)
671 {
672 if (parser) {
673 config_close(parser);
674 parser = NULL;
675 }
676 }
677
free_servtab_strings(servtab_t * cp)678 static void free_servtab_strings(servtab_t *cp)
679 {
680 int i;
681
682 free(cp->se_local_hostname);
683 free(cp->se_service);
684 free(cp->se_proto);
685 free(cp->se_user);
686 free(cp->se_group);
687 free(cp->se_lsa); /* not a string in fact */
688 free(cp->se_program);
689 for (i = 0; i < MAXARGV; i++)
690 free(cp->se_argv[i]);
691 }
692
new_servtab(void)693 static servtab_t *new_servtab(void)
694 {
695 servtab_t *newtab = xzalloc(sizeof(servtab_t));
696 newtab->se_fd = -1; /* paranoia */
697 return newtab;
698 }
699
dup_servtab(servtab_t * sep)700 static servtab_t *dup_servtab(servtab_t *sep)
701 {
702 servtab_t *newtab;
703 int argc;
704
705 newtab = new_servtab();
706 *newtab = *sep; /* struct copy */
707 /* deep-copying strings */
708 newtab->se_service = xstrdup(newtab->se_service);
709 newtab->se_proto = xstrdup(newtab->se_proto);
710 newtab->se_user = xstrdup(newtab->se_user);
711 newtab->se_group = xstrdup(newtab->se_group);
712 newtab->se_program = xstrdup(newtab->se_program);
713 for (argc = 0; argc <= MAXARGV; argc++)
714 newtab->se_argv[argc] = xstrdup(newtab->se_argv[argc]);
715 /* NB: se_fd, se_hostaddr and se_next are always
716 * overwrittend by callers, so we don't bother resetting them
717 * to NULL/0/-1 etc */
718
719 return newtab;
720 }
721
722 /* gcc generates much more code if this is inlined */
parse_one_line(void)723 static NOINLINE servtab_t *parse_one_line(void)
724 {
725 int argc;
726 char *token[6+MAXARGV];
727 char *p, *arg;
728 char *hostdelim;
729 servtab_t *sep;
730 servtab_t *nsep;
731 new:
732 sep = new_servtab();
733 more:
734 argc = config_read(parser, token, 6+MAXARGV, 1, "# \t", PARSE_NORMAL);
735 if (!argc) {
736 free(sep);
737 return NULL;
738 }
739
740 /* [host:]service socktype proto wait user[:group] prog [args] */
741 /* Check for "host:...." line */
742 arg = token[0];
743 hostdelim = strrchr(arg, ':');
744 if (hostdelim) {
745 *hostdelim = '\0';
746 sep->se_local_hostname = xstrdup(arg);
747 arg = hostdelim + 1;
748 if (*arg == '\0' && argc == 1) {
749 /* Line has just "host:", change the
750 * default host for the following lines. */
751 free(default_local_hostname);
752 default_local_hostname = sep->se_local_hostname;
753 /*sep->se_local_hostname = NULL; - redundant */
754 /* (we'll overwrite this field anyway) */
755 goto more;
756 }
757 } else
758 sep->se_local_hostname = xstrdup(default_local_hostname);
759
760 /* service socktype proto wait user[:group] prog [args] */
761 sep->se_service = xstrdup(arg);
762
763 /* socktype proto wait user[:group] prog [args] */
764 if (argc < 6) {
765 parse_err:
766 bb_error_msg("parse error on line %u, line is ignored",
767 parser->lineno);
768 /* Just "goto more" can make sep to carry over e.g.
769 * "rpc"-ness (by having se_rpcver_lo != 0).
770 * We will be more paranoid: */
771 free_servtab_strings(sep);
772 free(sep);
773 goto new;
774 }
775
776 {
777 static const int8_t SOCK_xxx[] ALIGN1 = {
778 -1,
779 SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
780 SOCK_SEQPACKET, SOCK_RAW
781 };
782 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
783 "stream""\0" "dgram""\0" "rdm""\0"
784 "seqpacket""\0" "raw""\0"
785 , token[1])];
786 }
787
788 /* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
789 sep->se_proto = arg = xstrdup(token[2]);
790 if (strcmp(arg, "unix") == 0) {
791 sep->se_family = AF_UNIX;
792 } else {
793 char *six;
794 sep->se_family = AF_INET;
795 six = last_char_is(arg, '6');
796 if (six) {
797 #if ENABLE_FEATURE_IPV6
798 *six = '\0';
799 sep->se_family = AF_INET6;
800 #else
801 bb_error_msg("%s: no support for IPv6", sep->se_proto);
802 goto parse_err;
803 #endif
804 }
805 if (is_prefixed_with(arg, "rpc/")) {
806 #if ENABLE_FEATURE_INETD_RPC
807 unsigned n;
808 arg += 4;
809 p = strchr(sep->se_service, '/');
810 if (p == NULL) {
811 bb_error_msg("no rpc version: '%s'", sep->se_service);
812 goto parse_err;
813 }
814 *p++ = '\0';
815 n = bb_strtou(p, &p, 10);
816 if (n > INT_MAX) {
817 bad_ver_spec:
818 bb_simple_error_msg("bad rpc version");
819 goto parse_err;
820 }
821 sep->se_rpcver_lo = sep->se_rpcver_hi = n;
822 if (*p == '-') {
823 p++;
824 n = bb_strtou(p, &p, 10);
825 if (n > INT_MAX || (int)n < sep->se_rpcver_lo)
826 goto bad_ver_spec;
827 sep->se_rpcver_hi = n;
828 }
829 if (*p != '\0')
830 goto bad_ver_spec;
831 #else
832 bb_simple_error_msg("no support for rpc services");
833 goto parse_err;
834 #endif
835 }
836 /* we don't really need getprotobyname()! */
837 if (strcmp(arg, "tcp") == 0)
838 sep->se_proto_no = IPPROTO_TCP; /* = 6 */
839 if (strcmp(arg, "udp") == 0)
840 sep->se_proto_no = IPPROTO_UDP; /* = 17 */
841 if (six)
842 *six = '6';
843 if (!sep->se_proto_no) /* not tcp/udp?? */
844 goto parse_err;
845 }
846
847 /* [no]wait[.max] user[:group] prog [args] */
848 arg = token[3];
849 sep->se_max = max_concurrency;
850 p = strchr(arg, '.');
851 if (p) {
852 *p++ = '\0';
853 sep->se_max = bb_strtou(p, NULL, 10);
854 if (errno)
855 goto parse_err;
856 }
857 sep->se_wait = (arg[0] != 'n' || arg[1] != 'o');
858 if (!sep->se_wait) /* "no" seen */
859 arg += 2;
860 if (strcmp(arg, "wait") != 0)
861 goto parse_err;
862
863 /* user[:group] prog [args] */
864 sep->se_user = xstrdup(token[4]);
865 arg = strchr(sep->se_user, '.');
866 if (arg == NULL)
867 arg = strchr(sep->se_user, ':');
868 if (arg) {
869 *arg++ = '\0';
870 sep->se_group = xstrdup(arg);
871 }
872
873 /* prog [args] */
874 sep->se_program = xstrdup(token[5]);
875 #ifdef INETD_BUILTINS_ENABLED
876 if (strcmp(sep->se_program, "internal") == 0
877 && strlen(sep->se_service) <= 7
878 && (sep->se_socktype == SOCK_STREAM
879 || sep->se_socktype == SOCK_DGRAM)
880 ) {
881 unsigned i;
882 for (i = 0; i < ARRAY_SIZE(builtins); i++)
883 if (strncmp(builtins[i].bi_service7, sep->se_service, 7) == 0)
884 goto found_bi;
885 bb_error_msg("unknown internal service %s", sep->se_service);
886 goto parse_err;
887 found_bi:
888 sep->se_builtin = &builtins[i];
889 /* stream builtins must be "nowait", dgram must be "wait" */
890 if (sep->se_wait != (sep->se_socktype == SOCK_DGRAM))
891 goto parse_err;
892 }
893 #endif
894 argc = 0;
895 while (argc < MAXARGV && (arg = token[6+argc]) != NULL)
896 sep->se_argv[argc++] = xstrdup(arg);
897 /* Some inetd.conf files have no argv's, not even argv[0].
898 * Fix them up.
899 * (Technically, programs can be execed with argv[0] = NULL,
900 * but many programs do not like that at all) */
901 if (argc == 0)
902 sep->se_argv[0] = xstrdup(sep->se_program);
903
904 /* catch mixups. "<service> stream udp ..." == wtf */
905 if (sep->se_socktype == SOCK_STREAM) {
906 if (sep->se_proto_no == IPPROTO_UDP)
907 goto parse_err;
908 }
909 if (sep->se_socktype == SOCK_DGRAM) {
910 if (sep->se_proto_no == IPPROTO_TCP)
911 goto parse_err;
912 }
913
914 //bb_error_msg(
915 // "ENTRY[%s][%s][%s][%d][%d][%d][%d][%d][%s][%s][%s]",
916 // sep->se_local_hostname, sep->se_service, sep->se_proto, sep->se_wait, sep->se_proto_no,
917 // sep->se_max, sep->se_count, sep->se_time, sep->se_user, sep->se_group, sep->se_program);
918
919 /* check if the hostname specifier is a comma separated list
920 * of hostnames. we'll make new entries for each address. */
921 while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
922 nsep = dup_servtab(sep);
923 /* NUL terminate the hostname field of the existing entry,
924 * and make a dup for the new entry. */
925 *hostdelim++ = '\0';
926 nsep->se_local_hostname = xstrdup(hostdelim);
927 nsep->se_next = sep->se_next;
928 sep->se_next = nsep;
929 }
930
931 /* was doing it here: */
932 /* DNS resolution, create copies for each IP address */
933 /* IPv6-ization destroyed it :( */
934
935 return sep;
936 }
937
insert_in_servlist(servtab_t * cp)938 static servtab_t *insert_in_servlist(servtab_t *cp)
939 {
940 servtab_t *sep;
941 sigset_t omask;
942
943 sep = new_servtab();
944 *sep = *cp; /* struct copy */
945 sep->se_fd = -1;
946 #if ENABLE_FEATURE_INETD_RPC
947 sep->se_rpcprog = -1;
948 #endif
949 block_CHLD_HUP_ALRM(&omask);
950 sep->se_next = serv_list;
951 serv_list = sep;
952 restore_sigmask(&omask);
953 return sep;
954 }
955
same_serv_addr_proto(servtab_t * old,servtab_t * new)956 static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
957 {
958 if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
959 return 0;
960 if (strcmp(old->se_service, new->se_service) != 0)
961 return 0;
962 if (strcmp(old->se_proto, new->se_proto) != 0)
963 return 0;
964 return 1;
965 }
966
reread_config_file(int sig UNUSED_PARAM)967 static void reread_config_file(int sig UNUSED_PARAM)
968 {
969 servtab_t *sep, *cp, **sepp;
970 len_and_sockaddr *lsa;
971 sigset_t omask;
972 unsigned n;
973 uint16_t port;
974 int save_errno = errno;
975
976 if (!reopen_config_file())
977 goto ret;
978 for (sep = serv_list; sep; sep = sep->se_next)
979 sep->se_checked = 0;
980
981 goto first_line;
982 while (1) {
983 if (cp == NULL) {
984 first_line:
985 cp = parse_one_line();
986 if (cp == NULL)
987 break;
988 }
989 for (sep = serv_list; sep; sep = sep->se_next)
990 if (same_serv_addr_proto(sep, cp))
991 goto equal_servtab;
992 /* not an "equal" servtab */
993 sep = insert_in_servlist(cp);
994 goto after_check;
995 equal_servtab:
996 {
997 int i;
998
999 block_CHLD_HUP_ALRM(&omask);
1000 #if ENABLE_FEATURE_INETD_RPC
1001 if (is_rpc_service(sep))
1002 unregister_rpc(sep);
1003 sep->se_rpcver_lo = cp->se_rpcver_lo;
1004 sep->se_rpcver_hi = cp->se_rpcver_hi;
1005 #endif
1006 if (cp->se_wait == 0) {
1007 /* New config says "nowait". If old one
1008 * was "wait", we currently may be waiting
1009 * for a child (and not accepting connects).
1010 * Stop waiting, start listening again.
1011 * (if it's not true, this op is harmless) */
1012 add_fd_to_set(sep->se_fd);
1013 }
1014 sep->se_wait = cp->se_wait;
1015 sep->se_max = cp->se_max;
1016 /* string fields need more love - we don't want to leak them */
1017 #define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
1018 SWAP(char*, sep->se_user, cp->se_user);
1019 SWAP(char*, sep->se_group, cp->se_group);
1020 SWAP(char*, sep->se_program, cp->se_program);
1021 for (i = 0; i < MAXARGV; i++)
1022 SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
1023 #undef SWAP
1024 restore_sigmask(&omask);
1025 free_servtab_strings(cp);
1026 }
1027 after_check:
1028 /* cp->string_fields are consumed by insert_in_servlist()
1029 * or freed at this point, cp itself is not yet freed. */
1030 sep->se_checked = 1;
1031
1032 /* create new len_and_sockaddr */
1033 switch (sep->se_family) {
1034 struct sockaddr_un *sun;
1035 case AF_UNIX:
1036 lsa = xzalloc_lsa(AF_UNIX);
1037 sun = (struct sockaddr_un*)&lsa->u.sa;
1038 safe_strncpy(sun->sun_path, sep->se_service, sizeof(sun->sun_path));
1039 break;
1040
1041 default: /* case AF_INET, case AF_INET6 */
1042 n = bb_strtou(sep->se_service, NULL, 10);
1043 #if ENABLE_FEATURE_INETD_RPC
1044 if (is_rpc_service(sep)) {
1045 sep->se_rpcprog = n;
1046 if (errno) { /* se_service is not numeric */
1047 struct rpcent *rp = getrpcbyname(sep->se_service);
1048 if (rp == NULL) {
1049 bb_error_msg("%s: unknown rpc service", sep->se_service);
1050 goto next_cp;
1051 }
1052 sep->se_rpcprog = rp->r_number;
1053 }
1054 if (sep->se_fd == -1)
1055 prepare_socket_fd(sep);
1056 if (sep->se_fd != -1)
1057 register_rpc(sep);
1058 goto next_cp;
1059 }
1060 #endif
1061 /* what port to listen on? */
1062 port = htons(n);
1063 if (errno || n > 0xffff) { /* se_service is not numeric */
1064 char protoname[4];
1065 struct servent *sp;
1066 /* can result only in "tcp" or "udp": */
1067 safe_strncpy(protoname, sep->se_proto, 4);
1068 sp = getservbyname(sep->se_service, protoname);
1069 if (sp == NULL) {
1070 bb_error_msg("%s/%s: unknown service",
1071 sep->se_service, sep->se_proto);
1072 goto next_cp;
1073 }
1074 port = sp->s_port;
1075 }
1076 if (LONE_CHAR(sep->se_local_hostname, '*')) {
1077 lsa = xzalloc_lsa(sep->se_family);
1078 set_nport(&lsa->u.sa, port);
1079 } else {
1080 lsa = host_and_af2sockaddr(sep->se_local_hostname,
1081 ntohs(port), sep->se_family);
1082 if (!lsa) {
1083 bb_error_msg("%s/%s: unknown host '%s'",
1084 sep->se_service, sep->se_proto,
1085 sep->se_local_hostname);
1086 goto next_cp;
1087 }
1088 }
1089 break;
1090 } /* end of "switch (sep->se_family)" */
1091
1092 /* did lsa change? Then close/open */
1093 if (sep->se_lsa == NULL
1094 || lsa->len != sep->se_lsa->len
1095 || memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
1096 ) {
1097 remove_fd_from_set(sep->se_fd);
1098 maybe_close(sep->se_fd);
1099 free(sep->se_lsa);
1100 sep->se_lsa = lsa;
1101 sep->se_fd = -1;
1102 } else {
1103 free(lsa);
1104 }
1105 if (sep->se_fd == -1)
1106 prepare_socket_fd(sep);
1107 next_cp:
1108 sep = cp->se_next;
1109 free(cp);
1110 cp = sep;
1111 } /* end of "while (1) parse lines" */
1112 close_config_file();
1113
1114 /* Purge anything not looked at above - these are stale entries,
1115 * new config file doesnt have them. */
1116 block_CHLD_HUP_ALRM(&omask);
1117 sepp = &serv_list;
1118 while ((sep = *sepp) != NULL) {
1119 if (sep->se_checked) {
1120 sepp = &sep->se_next;
1121 continue;
1122 }
1123 *sepp = sep->se_next;
1124 remove_fd_from_set(sep->se_fd);
1125 maybe_close(sep->se_fd);
1126 #if ENABLE_FEATURE_INETD_RPC
1127 if (is_rpc_service(sep))
1128 unregister_rpc(sep);
1129 #endif
1130 if (sep->se_family == AF_UNIX)
1131 unlink(sep->se_service);
1132 free_servtab_strings(sep);
1133 free(sep);
1134 }
1135 restore_sigmask(&omask);
1136 ret:
1137 errno = save_errno;
1138 }
1139
reap_child(int sig UNUSED_PARAM)1140 static void reap_child(int sig UNUSED_PARAM)
1141 {
1142 pid_t pid;
1143 int status;
1144 servtab_t *sep;
1145 int save_errno = errno;
1146
1147 for (;;) {
1148 pid = wait_any_nohang(&status);
1149 if (pid <= 0)
1150 break;
1151 for (sep = serv_list; sep; sep = sep->se_next) {
1152 if (sep->se_wait != pid)
1153 continue;
1154 /* One of our "wait" services */
1155 if (WIFEXITED(status) && WEXITSTATUS(status))
1156 bb_error_msg("%s: exit status %u",
1157 sep->se_program, WEXITSTATUS(status));
1158 else if (WIFSIGNALED(status))
1159 bb_error_msg("%s: exit signal %u",
1160 sep->se_program, WTERMSIG(status));
1161 sep->se_wait = 1;
1162 add_fd_to_set(sep->se_fd);
1163 break;
1164 }
1165 }
1166 errno = save_errno;
1167 }
1168
retry_network_setup(int sig UNUSED_PARAM)1169 static void retry_network_setup(int sig UNUSED_PARAM)
1170 {
1171 int save_errno = errno;
1172 servtab_t *sep;
1173
1174 alarm_armed = 0;
1175 for (sep = serv_list; sep; sep = sep->se_next) {
1176 if (sep->se_fd == -1) {
1177 prepare_socket_fd(sep);
1178 #if ENABLE_FEATURE_INETD_RPC
1179 if (sep->se_fd != -1 && is_rpc_service(sep))
1180 register_rpc(sep);
1181 #endif
1182 }
1183 }
1184 errno = save_errno;
1185 }
1186
clean_up_and_exit(int sig UNUSED_PARAM)1187 static void clean_up_and_exit(int sig UNUSED_PARAM)
1188 {
1189 servtab_t *sep;
1190
1191 /* XXX signal race walking sep list */
1192 for (sep = serv_list; sep; sep = sep->se_next) {
1193 if (sep->se_fd == -1)
1194 continue;
1195
1196 switch (sep->se_family) {
1197 case AF_UNIX:
1198 unlink(sep->se_service);
1199 break;
1200 default: /* case AF_INET, AF_INET6 */
1201 #if ENABLE_FEATURE_INETD_RPC
1202 if (sep->se_wait == 1 && is_rpc_service(sep))
1203 unregister_rpc(sep); /* XXX signal race */
1204 #endif
1205 break;
1206 }
1207 if (ENABLE_FEATURE_CLEAN_UP)
1208 close(sep->se_fd);
1209 }
1210 remove_pidfile_std_path_and_ext("inetd");
1211 exit(EXIT_SUCCESS);
1212 }
1213
1214 int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
inetd_main(int argc UNUSED_PARAM,char ** argv)1215 int inetd_main(int argc UNUSED_PARAM, char **argv)
1216 {
1217 struct sigaction sa, saved_pipe_handler;
1218 servtab_t *sep, *sep2;
1219 struct passwd *pwd;
1220 struct group *grp = grp; /* for compiler */
1221 int opt;
1222 pid_t pid;
1223 sigset_t omask;
1224
1225 INIT_G();
1226
1227 real_uid = getuid();
1228 if (real_uid != 0) /* run by non-root user */
1229 config_filename = NULL;
1230
1231 /* -q N, -R N */
1232 opt = getopt32(argv, "R:+feq:+", &max_concurrency, &global_queuelen);
1233 argv += optind;
1234 //argc -= optind;
1235 if (argv[0])
1236 config_filename = argv[0];
1237 if (config_filename == NULL)
1238 bb_simple_error_msg_and_die("non-root must specify config file");
1239 if (!(opt & 2))
1240 bb_daemonize_or_rexec(0, argv - optind);
1241 else
1242 bb_sanitize_stdio();
1243 if (!(opt & 4)) {
1244 /* LOG_NDELAY: connect to syslog daemon NOW.
1245 * Otherwise, we may open syslog socket
1246 * in vforked child, making opened fds and syslog()
1247 * internal state inconsistent.
1248 * This was observed to leak file descriptors. */
1249 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1250 logmode = LOGMODE_SYSLOG;
1251 }
1252
1253 if (real_uid == 0) {
1254 /* run by root, ensure groups vector gets trashed */
1255 gid_t gid = getgid();
1256 setgroups(1, &gid);
1257 }
1258
1259 write_pidfile_std_path_and_ext("inetd");
1260
1261 /* never fails under Linux (except if you pass it bad arguments) */
1262 getrlimit(RLIMIT_NOFILE, &rlim_ofile);
1263 rlim_ofile_cur = rlim_ofile.rlim_cur;
1264 if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
1265 rlim_ofile_cur = OPEN_MAX;
1266
1267 memset(&sa, 0, sizeof(sa));
1268 /*sigemptyset(&sa.sa_mask); - memset did it */
1269 sigaddset(&sa.sa_mask, SIGALRM);
1270 sigaddset(&sa.sa_mask, SIGCHLD);
1271 sigaddset(&sa.sa_mask, SIGHUP);
1272 //FIXME: explain why no SA_RESTART
1273 //FIXME: retry_network_setup is unsafe to run in signal handler (many reasons)!
1274 sa.sa_handler = retry_network_setup;
1275 sigaction_set(SIGALRM, &sa);
1276 //FIXME: reread_config_file is unsafe to run in signal handler(many reasons)!
1277 sa.sa_handler = reread_config_file;
1278 sigaction_set(SIGHUP, &sa);
1279 //FIXME: reap_child is unsafe to run in signal handler (uses stdio)!
1280 sa.sa_handler = reap_child;
1281 sigaction_set(SIGCHLD, &sa);
1282 //FIXME: clean_up_and_exit is unsafe to run in signal handler (uses stdio)!
1283 sa.sa_handler = clean_up_and_exit;
1284 sigaction_set(SIGTERM, &sa);
1285 sa.sa_handler = clean_up_and_exit;
1286 sigaction_set(SIGINT, &sa);
1287 sa.sa_handler = SIG_IGN;
1288 sigaction(SIGPIPE, &sa, &saved_pipe_handler);
1289
1290 reread_config_file(SIGHUP); /* load config from file */
1291
1292 for (;;) {
1293 int ready_fd_cnt;
1294 int ctrl, accepted_fd, new_udp_fd;
1295 fd_set readable;
1296
1297 if (maxsock < 0)
1298 recalculate_maxsock();
1299
1300 readable = allsock; /* struct copy */
1301 /* if there are no fds to wait on, we will block
1302 * until signal wakes us up (maxsock == 0, but readable
1303 * never contains fds 0 and 1...) */
1304 ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
1305 if (ready_fd_cnt < 0) {
1306 if (errno != EINTR) {
1307 bb_simple_perror_msg("select");
1308 sleep1();
1309 }
1310 continue;
1311 }
1312 dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
1313
1314 for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
1315 if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1316 continue;
1317
1318 dbg("ready fd:%d\n", sep->se_fd);
1319 ready_fd_cnt--;
1320 ctrl = sep->se_fd;
1321 accepted_fd = -1;
1322 new_udp_fd = -1;
1323 if (!sep->se_wait) {
1324 if (sep->se_socktype == SOCK_STREAM) {
1325 ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
1326 dbg("accepted_fd:%d\n", accepted_fd);
1327 if (ctrl < 0) {
1328 if (errno != EINTR)
1329 bb_perror_msg("accept (for %s)", sep->se_service);
1330 continue;
1331 }
1332 }
1333 /* "nowait" udp */
1334 if (sep->se_socktype == SOCK_DGRAM
1335 && sep->se_family != AF_UNIX
1336 ) {
1337 /* How udp "nowait" works:
1338 * child peeks at (received and buffered by kernel) UDP packet,
1339 * performs connect() on the socket so that it is linked only
1340 * to this peer. But this also affects parent, because descriptors
1341 * are shared after fork() a-la dup(). When parent performs
1342 * select(), it will see this descriptor connected to the peer (!)
1343 * and still readable, will act on it and mess things up
1344 * (can create many copies of same child, etc).
1345 * Parent must create and use new socket instead. */
1346 new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
1347 dbg("new_udp_fd:%d\n", new_udp_fd);
1348 if (new_udp_fd < 0) { /* error: eat packet, forget about it */
1349 udp_err:
1350 recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
1351 continue;
1352 }
1353 setsockopt_reuseaddr(new_udp_fd);
1354 /* TODO: better do bind after fork in parent,
1355 * so that we don't have two wildcard bound sockets
1356 * even for a brief moment? */
1357 if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
1358 dbg("bind(new_udp_fd) failed\n");
1359 close(new_udp_fd);
1360 goto udp_err;
1361 }
1362 dbg("bind(new_udp_fd) succeeded\n");
1363 }
1364 }
1365
1366 block_CHLD_HUP_ALRM(&omask);
1367 pid = 0;
1368 #ifdef INETD_BUILTINS_ENABLED
1369 /* do we need to fork? */
1370 if (sep->se_builtin == NULL
1371 || (sep->se_socktype == SOCK_STREAM
1372 && sep->se_builtin->bi_fork))
1373 #endif
1374 {
1375 if (sep->se_max != 0) {
1376 if (++sep->se_count == 1)
1377 sep->se_time = monotonic_sec();
1378 else if (sep->se_count >= sep->se_max) {
1379 unsigned now = monotonic_sec();
1380 /* did we accumulate se_max connects too quickly? */
1381 if (now - sep->se_time <= CNT_INTERVAL) {
1382 bb_error_msg("%s/%s: too many connections, pausing",
1383 sep->se_service, sep->se_proto);
1384 remove_fd_from_set(sep->se_fd);
1385 close(sep->se_fd);
1386 sep->se_fd = -1;
1387 sep->se_count = 0;
1388 rearm_alarm(); /* will revive it in RETRYTIME sec */
1389 restore_sigmask(&omask);
1390 maybe_close(new_udp_fd);
1391 maybe_close(accepted_fd);
1392 continue; /* -> check next fd in fd set */
1393 }
1394 sep->se_count = 0;
1395 }
1396 }
1397 /* on NOMMU, streamed chargen
1398 * builtin wouldn't work, but it is
1399 * not allowed on NOMMU (ifdefed out) */
1400 #ifdef INETD_BUILTINS_ENABLED
1401 if (BB_MMU && sep->se_builtin)
1402 pid = fork();
1403 else
1404 #endif
1405 pid = vfork();
1406
1407 if (pid < 0) { /* fork error */
1408 bb_simple_perror_msg("vfork"+1);
1409 sleep1();
1410 restore_sigmask(&omask);
1411 maybe_close(new_udp_fd);
1412 maybe_close(accepted_fd);
1413 continue; /* -> check next fd in fd set */
1414 }
1415 if (pid == 0)
1416 pid--; /* -1: "we did fork and we are child" */
1417 }
1418 /* if pid == 0 here, we didn't fork */
1419
1420 if (pid > 0) { /* parent */
1421 if (sep->se_wait) {
1422 /* wait: we passed socket to child,
1423 * will wait for child to terminate */
1424 sep->se_wait = pid;
1425 remove_fd_from_set(sep->se_fd);
1426 }
1427 if (new_udp_fd >= 0) {
1428 /* udp nowait: child connected the socket,
1429 * we created and will use new, unconnected one */
1430 xmove_fd(new_udp_fd, sep->se_fd);
1431 dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
1432 }
1433 restore_sigmask(&omask);
1434 maybe_close(accepted_fd);
1435 continue; /* -> check next fd in fd set */
1436 }
1437
1438 /* we are either child or didn't fork at all */
1439 #ifdef INETD_BUILTINS_ENABLED
1440 if (sep->se_builtin) {
1441 if (pid) { /* "pid" is -1: we did fork */
1442 close(sep->se_fd); /* listening socket */
1443 dbg("closed sep->se_fd:%d\n", sep->se_fd);
1444 logmode = LOGMODE_NONE; /* make xwrite etc silent */
1445 }
1446 restore_sigmask(&omask);
1447 if (sep->se_socktype == SOCK_STREAM)
1448 sep->se_builtin->bi_stream_fn(ctrl, sep);
1449 else
1450 sep->se_builtin->bi_dgram_fn(ctrl, sep);
1451 if (pid) /* we did fork */
1452 _exit(EXIT_FAILURE);
1453 maybe_close(accepted_fd);
1454 continue; /* -> check next fd in fd set */
1455 }
1456 #endif
1457 /* child */
1458 setsid();
1459 /* "nowait" udp */
1460 if (new_udp_fd >= 0) {
1461 len_and_sockaddr *lsa;
1462 int r;
1463
1464 close(new_udp_fd);
1465 dbg("closed new_udp_fd:%d\n", new_udp_fd);
1466 lsa = xzalloc_lsa(sep->se_family);
1467 /* peek at the packet and remember peer addr */
1468 r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
1469 &lsa->u.sa, &lsa->len);
1470 if (r < 0)
1471 goto do_exit1;
1472 /* make this socket "connected" to peer addr:
1473 * only packets from this peer will be recv'ed,
1474 * and bare write()/send() will work on it */
1475 connect(ctrl, &lsa->u.sa, lsa->len);
1476 dbg("connected ctrl:%d to remote peer\n", ctrl);
1477 free(lsa);
1478 }
1479 /* prepare env and exec program */
1480 pwd = getpwnam(sep->se_user);
1481 if (pwd == NULL) {
1482 bb_error_msg("%s: no such %s", sep->se_user, "user");
1483 goto do_exit1;
1484 }
1485 if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1486 bb_error_msg("%s: no such %s", sep->se_group, "group");
1487 goto do_exit1;
1488 }
1489 if (real_uid != 0 && real_uid != pwd->pw_uid) {
1490 /* a user running private inetd */
1491 bb_simple_error_msg("non-root must run services as himself");
1492 goto do_exit1;
1493 }
1494 if (pwd->pw_uid != real_uid) {
1495 if (sep->se_group)
1496 pwd->pw_gid = grp->gr_gid;
1497 /* initgroups, setgid, setuid: */
1498 change_identity(pwd);
1499 } else if (sep->se_group) {
1500 xsetgid(grp->gr_gid);
1501 setgroups(1, &grp->gr_gid);
1502 }
1503 if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1504 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1505 bb_simple_perror_msg("setrlimit");
1506
1507 /* closelog(); - WRONG. we are after vfork,
1508 * this may confuse syslog() internal state.
1509 * Let's hope libc sets syslog fd to CLOEXEC...
1510 */
1511 xmove_fd(ctrl, STDIN_FILENO);
1512 xdup2(STDIN_FILENO, STDOUT_FILENO);
1513 dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
1514 /* manpages of inetd I managed to find either say
1515 * that stderr is also redirected to the network,
1516 * or do not talk about redirection at all (!) */
1517 if (!sep->se_wait) /* only for usual "tcp nowait" */
1518 xdup2(STDIN_FILENO, STDERR_FILENO);
1519 /* NB: among others, this loop closes listening sockets
1520 * for nowait stream children */
1521 for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
1522 if (sep2->se_fd != ctrl)
1523 maybe_close(sep2->se_fd);
1524 sigaction_set(SIGPIPE, &saved_pipe_handler);
1525 restore_sigmask(&omask);
1526 dbg("execing:'%s'\n", sep->se_program);
1527 BB_EXECVP(sep->se_program, sep->se_argv);
1528 bb_perror_msg("can't execute '%s'", sep->se_program);
1529 do_exit1:
1530 /* eat packet in udp case */
1531 if (sep->se_socktype != SOCK_STREAM)
1532 recv(0, line, LINE_SIZE, MSG_DONTWAIT);
1533 _exit(EXIT_FAILURE);
1534 } /* for (sep = servtab...) */
1535 } /* for (;;) */
1536 }
1537
1538 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
1539 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1540 # if !BB_MMU
1541 static const char *const cat_args[] = { "cat", NULL };
1542 # endif
1543 #endif
1544
1545 /*
1546 * Internet services provided internally by inetd:
1547 */
1548 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1549 /* Echo service -- echo data back. */
1550 /* ARGSUSED */
echo_stream(int s,servtab_t * sep UNUSED_PARAM)1551 static void FAST_FUNC echo_stream(int s, servtab_t *sep UNUSED_PARAM)
1552 {
1553 # if BB_MMU
1554 while (1) {
1555 ssize_t sz = safe_read(s, line, LINE_SIZE);
1556 if (sz <= 0)
1557 break;
1558 xwrite(s, line, sz);
1559 }
1560 # else
1561 /* We are after vfork here! */
1562 /* move network socket to stdin/stdout */
1563 xmove_fd(s, STDIN_FILENO);
1564 xdup2(STDIN_FILENO, STDOUT_FILENO);
1565 /* no error messages please... */
1566 close(STDERR_FILENO);
1567 xopen(bb_dev_null, O_WRONLY);
1568 BB_EXECVP("cat", (char**)cat_args);
1569 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1570 # endif
1571 }
echo_dg(int s,servtab_t * sep)1572 static void FAST_FUNC echo_dg(int s, servtab_t *sep)
1573 {
1574 enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
1575 char *buf = xmalloc(BUFSIZE); /* too big for stack */
1576 int sz;
1577 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1578
1579 lsa->len = sep->se_lsa->len;
1580 /* dgram builtins are non-forking - DONT BLOCK! */
1581 sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
1582 if (sz > 0)
1583 sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
1584 free(buf);
1585 }
1586 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1587
1588
1589 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1590 /* Discard service -- ignore data. */
1591 /* ARGSUSED */
discard_stream(int s,servtab_t * sep UNUSED_PARAM)1592 static void FAST_FUNC discard_stream(int s, servtab_t *sep UNUSED_PARAM)
1593 {
1594 # if BB_MMU
1595 while (safe_read(s, line, LINE_SIZE) > 0)
1596 continue;
1597 # else
1598 /* We are after vfork here! */
1599 /* move network socket to stdin */
1600 xmove_fd(s, STDIN_FILENO);
1601 /* discard output */
1602 close(STDOUT_FILENO);
1603 xopen(bb_dev_null, O_WRONLY);
1604 /* no error messages please... */
1605 xdup2(STDOUT_FILENO, STDERR_FILENO);
1606 BB_EXECVP("cat", (char**)cat_args);
1607 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1608 # endif
1609 }
1610 /* ARGSUSED */
discard_dg(int s,servtab_t * sep UNUSED_PARAM)1611 static void FAST_FUNC discard_dg(int s, servtab_t *sep UNUSED_PARAM)
1612 {
1613 /* dgram builtins are non-forking - DONT BLOCK! */
1614 recv(s, line, LINE_SIZE, MSG_DONTWAIT);
1615 }
1616 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1617
1618
1619 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1620 #define LINESIZ 72
init_ring(void)1621 static void init_ring(void)
1622 {
1623 int i;
1624
1625 end_ring = ring;
1626 for (i = ' '; i < 127; i++)
1627 *end_ring++ = i;
1628 }
1629 /* Character generator. MMU arches only. */
1630 /* ARGSUSED */
chargen_stream(int s,servtab_t * sep UNUSED_PARAM)1631 static void FAST_FUNC chargen_stream(int s, servtab_t *sep UNUSED_PARAM)
1632 {
1633 char *rs;
1634 int len;
1635 char text[LINESIZ + 2];
1636
1637 if (!end_ring) {
1638 init_ring();
1639 rs = ring;
1640 }
1641
1642 text[LINESIZ] = '\r';
1643 text[LINESIZ + 1] = '\n';
1644 rs = ring;
1645 for (;;) {
1646 len = end_ring - rs;
1647 if (len >= LINESIZ)
1648 memmove(text, rs, LINESIZ);
1649 else {
1650 memmove(text, rs, len);
1651 memmove(text + len, ring, LINESIZ - len);
1652 }
1653 if (++rs == end_ring)
1654 rs = ring;
1655 xwrite(s, text, sizeof(text));
1656 }
1657 }
1658 /* ARGSUSED */
chargen_dg(int s,servtab_t * sep)1659 static void FAST_FUNC chargen_dg(int s, servtab_t *sep)
1660 {
1661 int len;
1662 char text[LINESIZ + 2];
1663 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1664
1665 /* Eat UDP packet which started it all */
1666 /* dgram builtins are non-forking - DONT BLOCK! */
1667 lsa->len = sep->se_lsa->len;
1668 if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1669 return;
1670
1671 if (!end_ring) {
1672 init_ring();
1673 ring_pos = ring;
1674 }
1675
1676 len = end_ring - ring_pos;
1677 if (len >= LINESIZ)
1678 memmove(text, ring_pos, LINESIZ);
1679 else {
1680 memmove(text, ring_pos, len);
1681 memmove(text + len, ring, LINESIZ - len);
1682 }
1683 if (++ring_pos == end_ring)
1684 ring_pos = ring;
1685 text[LINESIZ] = '\r';
1686 text[LINESIZ + 1] = '\n';
1687 sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
1688 }
1689 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1690
1691
1692 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1693 /*
1694 * Return a machine readable date and time, in the form of the
1695 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
1696 * returns the number of seconds since midnight, Jan 1, 1970,
1697 * we must add 2208988800 seconds to this figure to make up for
1698 * some seventy years Bell Labs was asleep.
1699 */
machtime(void)1700 static NOINLINE uint32_t machtime(void)
1701 {
1702 struct timeval tv;
1703
1704 xgettimeofday(&tv);
1705 return htonl((uint32_t)(tv.tv_sec + 2208988800U));
1706 }
1707 /* ARGSUSED */
machtime_stream(int s,servtab_t * sep UNUSED_PARAM)1708 static void FAST_FUNC machtime_stream(int s, servtab_t *sep UNUSED_PARAM)
1709 {
1710 uint32_t result;
1711
1712 result = machtime();
1713 full_write(s, &result, sizeof(result));
1714 }
machtime_dg(int s,servtab_t * sep)1715 static void FAST_FUNC machtime_dg(int s, servtab_t *sep)
1716 {
1717 uint32_t result;
1718 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1719
1720 lsa->len = sep->se_lsa->len;
1721 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1722 return;
1723
1724 result = machtime();
1725 sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
1726 }
1727 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1728
1729
1730 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1731 /* Return human-readable time of day */
1732 /* ARGSUSED */
daytime_stream(int s,servtab_t * sep UNUSED_PARAM)1733 static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
1734 {
1735 time_t t;
1736
1737 time(&t);
1738 fdprintf(s, "%.24s\r\n", ctime(&t));
1739 }
daytime_dg(int s,servtab_t * sep)1740 static void FAST_FUNC daytime_dg(int s, servtab_t *sep)
1741 {
1742 time_t t;
1743 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1744
1745 lsa->len = sep->se_lsa->len;
1746 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1747 return;
1748
1749 t = time(NULL);
1750 sprintf(line, "%.24s\r\n", ctime(&t));
1751 sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
1752 }
1753 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */
1754