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busybox/networking/inetd.c
Denys Vlasenko f3d705f41b make --help texts smaller 
function                                             old     new   delta
packed_usage                                       31035   30968     -67

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-21 03:46:57 +01:00

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/* vi: set sw=4 ts=4: */
/* $Slackware: inetd.c 1.79s 2001/02/06 13:18:00 volkerdi Exp $ */
/* $OpenBSD: inetd.c,v 1.79 2001/01/30 08:30:57 deraadt Exp $ */
/* $NetBSD: inetd.c,v 1.11 1996/02/22 11:14:41 mycroft Exp $ */
/* Busybox port by Vladimir Oleynik (C) 2001-2005 <dzo@simtreas.ru> */
/* IPv6 support, many bug fixes by Denys Vlasenko (c) 2008 */
/*
* Copyright (c) 1983,1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* Inetd - Internet super-server
*
* This program invokes configured services when a connection
* from a peer is established or a datagram arrives.
* Connection-oriented services are invoked each time a
* connection is made, by creating a process. This process
* is passed the connection as file descriptor 0 and is
* expected to do a getpeername to find out peer's host
* and port.
* Datagram oriented services are invoked when a datagram
* arrives; a process is created and passed a pending message
* on file descriptor 0. peer's address can be obtained
* using recvfrom.
*
* Inetd uses a configuration file which is read at startup
* and, possibly, at some later time in response to a hangup signal.
* The configuration file is "free format" with fields given in the
* order shown below. Continuation lines for an entry must begin with
* a space or tab. All fields must be present in each entry.
*
* service_name must be in /etc/services
* socket_type stream/dgram/raw/rdm/seqpacket
* protocol must be in /etc/protocols
* (usually "tcp" or "udp")
* wait/nowait[.max] single-threaded/multi-threaded, max #
* user[.group] or user[:group] user/group to run daemon as
* server_program full path name
* server_program_arguments maximum of MAXARGS (20)
*
* For RPC services
* service_name/version must be in /etc/rpc
* socket_type stream/dgram/raw/rdm/seqpacket
* rpc/protocol "rpc/tcp" etc
* wait/nowait[.max] single-threaded/multi-threaded
* user[.group] or user[:group] user to run daemon as
* server_program full path name
* server_program_arguments maximum of MAXARGS (20)
*
* For non-RPC services, the "service name" can be of the form
* hostaddress:servicename, in which case the hostaddress is used
* as the host portion of the address to listen on. If hostaddress
* consists of a single '*' character, INADDR_ANY is used.
*
* A line can also consist of just
* hostaddress:
* where hostaddress is as in the preceding paragraph. Such a line must
* have no further fields; the specified hostaddress is remembered and
* used for all further lines that have no hostaddress specified,
* until the next such line (or EOF). (This is why * is provided to
* allow explicit specification of INADDR_ANY.) A line
* *:
* is implicitly in effect at the beginning of the file.
*
* The hostaddress specifier may (and often will) contain dots;
* the service name must not.
*
* For RPC services, host-address specifiers are accepted and will
* work to some extent; however, because of limitations in the
* portmapper interface, it will not work to try to give more than
* one line for any given RPC service, even if the host-address
* specifiers are different.
*
* Comment lines are indicated by a '#' in column 1.
*/
/* inetd rules for passing file descriptors to children
* (http://www.freebsd.org/cgi/man.cgi?query=inetd):
*
* The wait/nowait entry specifies whether the server that is invoked by
* inetd will take over the socket associated with the service access point,
* and thus whether inetd should wait for the server to exit before listen-
* ing for new service requests. Datagram servers must use "wait", as
* they are always invoked with the original datagram socket bound to the
* specified service address. These servers must read at least one datagram
* from the socket before exiting. If a datagram server connects to its
* peer, freeing the socket so inetd can receive further messages on the
* socket, it is said to be a "multi-threaded" server; it should read one
* datagram from the socket and create a new socket connected to the peer.
* It should fork, and the parent should then exit to allow inetd to check
* for new service requests to spawn new servers. Datagram servers which
* process all incoming datagrams on a socket and eventually time out are
* said to be "single-threaded". The comsat(8), biff(1) and talkd(8)
* utilities are both examples of the latter type of datagram server. The
* tftpd(8) utility is an example of a multi-threaded datagram server.
*
* Servers using stream sockets generally are multi-threaded and use the
* "nowait" entry. Connection requests for these services are accepted by
* inetd, and the server is given only the newly-accepted socket connected
* to a client of the service. Most stream-based services operate in this
* manner. Stream-based servers that use "wait" are started with the lis-
* tening service socket, and must accept at least one connection request
* before exiting. Such a server would normally accept and process incoming
* connection requests until a timeout.
*/
/* Despite of above doc saying that dgram services must use "wait",
* "udp nowait" servers are implemented in busyboxed inetd.
* IPv6 addresses are also implemented. However, they may look ugly -
* ":::service..." means "address '::' (IPv6 wildcard addr)":"service"...
* You have to put "tcp6"/"udp6" in protocol field to select IPv6.
*/
/* Here's the scoop concerning the user[:group] feature:
* 1) group is not specified:
* a) user = root: NO setuid() or setgid() is done
* b) other: initgroups(name, primary group)
* setgid(primary group as found in passwd)
* setuid()
* 2) group is specified:
* a) user = root: setgid(specified group)
* NO initgroups()
* NO setuid()
* b) other: initgroups(name, specified group)
* setgid(specified group)
* setuid()
*/
//config:config INETD
//config: bool "inetd"
//config: default y
//config: select FEATURE_SYSLOG
//config: help
//config: Internet superserver daemon
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_ECHO
//config: bool "Support echo service"
//config: default y
//config: depends on INETD
//config: help
//config: Echo received data internal inetd service
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
//config: bool "Support discard service"
//config: default y
//config: depends on INETD
//config: help
//config: Internet /dev/null internal inetd service
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_TIME
//config: bool "Support time service"
//config: default y
//config: depends on INETD
//config: help
//config: Return 32 bit time since 1900 internal inetd service
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
//config: bool "Support daytime service"
//config: default y
//config: depends on INETD
//config: help
//config: Return human-readable time internal inetd service
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
//config: bool "Support chargen service"
//config: default y
//config: depends on INETD
//config: help
//config: Familiar character generator internal inetd service
//config:
//config:config FEATURE_INETD_RPC
//config: bool "Support RPC services"
//config: default n # very rarely used, and needs Sun RPC support in libc
//config: depends on INETD
//config: select FEATURE_HAVE_RPC
//config: help
//config: Support Sun-RPC based services
//applet:IF_INETD(APPLET(inetd, BB_DIR_USR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_INETD) += inetd.o
//usage:#define inetd_trivial_usage
//usage: "[-fe] [-q N] [-R N] [CONFFILE]"
//usage:#define inetd_full_usage "\n\n"
//usage: "Listen for network connections and launch programs\n"
//usage: "\n -f Run in foreground"
//usage: "\n -e Log to stderr"
//usage: "\n -q N Socket listen queue (default 128)"
//usage: "\n -R N Pause services after N connects/min"
//usage: "\n (default 0 - disabled)"
#include <syslog.h>
#include <sys/resource.h> /* setrlimit */
#include <sys/socket.h> /* un.h may need this */
#include <sys/un.h>
#include "libbb.h"
#include "common_bufsiz.h"
#if ENABLE_FEATURE_INETD_RPC
# if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
# error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support"
# endif
# include <rpc/rpc.h>
# include <rpc/pmap_clnt.h>
#endif
#if !BB_MMU
/* stream version of chargen is forking but not execing,
* can't do that (easily) on NOMMU */
#undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
#endif
#define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
#define RETRYTIME 60 /* retry after bind or server fail */
// TODO: explain, or get rid of setrlimit games
#ifndef RLIMIT_NOFILE
#define RLIMIT_NOFILE RLIMIT_OFILE
#endif
#ifndef OPEN_MAX
#define OPEN_MAX 64
#endif
/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
#define FD_MARGIN 8
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
# define INETD_BUILTINS_ENABLED
#endif
typedef struct servtab_t {
/* The most frequently referenced one: */
int se_fd; /* open descriptor */
/* NB: 'biggest fields last' saves on code size (~250 bytes) */
/* [addr:]service socktype proto wait user[:group] prog [args] */
char *se_local_hostname; /* addr to listen on */
char *se_service; /* "80" or "www" or "mount/2[-3]" */
/* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
#if ENABLE_FEATURE_INETD_RPC
int se_rpcprog; /* rpc program number */
int se_rpcver_lo; /* rpc program lowest version */
int se_rpcver_hi; /* rpc program highest version */
#define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
#else
#define is_rpc_service(sep) 0
#endif
pid_t se_wait; /* 0:"nowait", 1:"wait", >1:"wait" */
/* and waiting for this pid */
socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
family_t se_family; /* AF_UNIX/INET[6] */
/* se_proto_no is used by RPC code only... hmm */
smallint se_proto_no; /* IPPROTO_TCP/UDP, n/a for AF_UNIX */
smallint se_checked; /* looked at during merge */
unsigned se_max; /* allowed instances per minute */
unsigned se_count; /* number started since se_time */
unsigned se_time; /* when we started counting */
char *se_user; /* user name to run as */
char *se_group; /* group name to run as, can be NULL */
#ifdef INETD_BUILTINS_ENABLED
const struct builtin *se_builtin; /* if built-in, description */
#endif
struct servtab_t *se_next;
len_and_sockaddr *se_lsa;
char *se_program; /* server program */
#define MAXARGV 20
char *se_argv[MAXARGV + 1]; /* program arguments */
} servtab_t;
#ifdef INETD_BUILTINS_ENABLED
/* Echo received data */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
static void FAST_FUNC echo_stream(int, servtab_t *);
static void FAST_FUNC echo_dg(int, servtab_t *);
#endif
/* Internet /dev/null */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
static void FAST_FUNC discard_stream(int, servtab_t *);
static void FAST_FUNC discard_dg(int, servtab_t *);
#endif
/* Return 32 bit time since 1900 */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
static void FAST_FUNC machtime_stream(int, servtab_t *);
static void FAST_FUNC machtime_dg(int, servtab_t *);
#endif
/* Return human-readable time */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
static void FAST_FUNC daytime_stream(int, servtab_t *);
static void FAST_FUNC daytime_dg(int, servtab_t *);
#endif
/* Familiar character generator */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
static void FAST_FUNC chargen_stream(int, servtab_t *);
static void FAST_FUNC chargen_dg(int, servtab_t *);
#endif
struct builtin {
/* NB: not necessarily NUL terminated */
char bi_service7[7]; /* internally provided service name */
uint8_t bi_fork; /* 1 if stream fn should run in child */
void (*bi_stream_fn)(int, servtab_t *) FAST_FUNC;
void (*bi_dgram_fn)(int, servtab_t *) FAST_FUNC;
};
static const struct builtin builtins[] = {
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
{ "echo", 1, echo_stream, echo_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
{ "discard", 1, discard_stream, discard_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
{ "chargen", 1, chargen_stream, chargen_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
{ "time", 0, machtime_stream, machtime_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
{ "daytime", 0, daytime_stream, daytime_dg },
#endif
};
#endif /* INETD_BUILTINS_ENABLED */
struct globals {
rlim_t rlim_ofile_cur;
struct rlimit rlim_ofile;
servtab_t *serv_list;
int global_queuelen;
int maxsock; /* max fd# in allsock, -1: unknown */
/* whenever maxsock grows, prev_maxsock is set to new maxsock,
* but if maxsock is set to -1, prev_maxsock is not changed */
int prev_maxsock;
unsigned max_concurrency;
smallint alarm_armed;
uid_t real_uid; /* user ID who ran us */
const char *config_filename;
parser_t *parser;
char *default_local_hostname;
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
char *end_ring;
char *ring_pos;
char ring[128];
#endif
fd_set allsock;
/* Used in next_line(), and as scratch read buffer */
char line[256]; /* _at least_ 256, see LINE_SIZE */
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
#define rlim_ofile_cur (G.rlim_ofile_cur )
#define rlim_ofile (G.rlim_ofile )
#define serv_list (G.serv_list )
#define global_queuelen (G.global_queuelen)
#define maxsock (G.maxsock )
#define prev_maxsock (G.prev_maxsock )
#define max_concurrency (G.max_concurrency)
#define alarm_armed (G.alarm_armed )
#define real_uid (G.real_uid )
#define config_filename (G.config_filename)
#define parser (G.parser )
#define default_local_hostname (G.default_local_hostname)
#define first_ps_byte (G.first_ps_byte )
#define last_ps_byte (G.last_ps_byte )
#define end_ring (G.end_ring )
#define ring_pos (G.ring_pos )
#define ring (G.ring )
#define allsock (G.allsock )
#define line (G.line )
#define INIT_G() do { \
setup_common_bufsiz(); \
BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
rlim_ofile_cur = OPEN_MAX; \
global_queuelen = 128; \
config_filename = "/etc/inetd.conf"; \
} while (0)
#if 1
# define dbg(...) ((void)0)
#else
# define dbg(...) \
do { \
int dbg_fd = open("inetd_debug.log", O_WRONLY | O_CREAT | O_APPEND, 0666); \
if (dbg_fd >= 0) { \
fdprintf(dbg_fd, "%d: ", getpid()); \
fdprintf(dbg_fd, __VA_ARGS__); \
close(dbg_fd); \
} \
} while (0)
#endif
static void maybe_close(int fd)
{
if (fd >= 0) {
close(fd);
dbg("closed fd:%d\n", fd);
}
}
// TODO: move to libbb?
static len_and_sockaddr *xzalloc_lsa(int family)
{
len_and_sockaddr *lsa;
int sz;
sz = sizeof(struct sockaddr_in);
if (family == AF_UNIX)
sz = sizeof(struct sockaddr_un);
#if ENABLE_FEATURE_IPV6
if (family == AF_INET6)
sz = sizeof(struct sockaddr_in6);
#endif
lsa = xzalloc(LSA_LEN_SIZE + sz);
lsa->len = sz;
lsa->u.sa.sa_family = family;
return lsa;
}
static void rearm_alarm(void)
{
if (!alarm_armed) {
alarm_armed = 1;
alarm(RETRYTIME);
}
}
static void block_CHLD_HUP_ALRM(sigset_t *m)
{
sigemptyset(m);
sigaddset(m, SIGCHLD);
sigaddset(m, SIGHUP);
sigaddset(m, SIGALRM);
sigprocmask(SIG_BLOCK, m, m); /* old sigmask is stored in m */
}
static void restore_sigmask(sigset_t *m)
{
sigprocmask(SIG_SETMASK, m, NULL);
}
#if ENABLE_FEATURE_INETD_RPC
static void register_rpc(servtab_t *sep)
{
int n;
struct sockaddr_in ir_sin;
socklen_t size;
size = sizeof(ir_sin);
if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
bb_perror_msg("getsockname");
return;
}
for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
pmap_unset(sep->se_rpcprog, n);
if (!pmap_set(sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port)))
bb_perror_msg("%s %s: pmap_set(%u,%u,%u,%u)",
sep->se_service, sep->se_proto,
sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port));
}
}
static void unregister_rpc(servtab_t *sep)
{
int n;
for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
if (!pmap_unset(sep->se_rpcprog, n))
bb_perror_msg("pmap_unset(%u,%u)", sep->se_rpcprog, n);
}
}
#endif /* FEATURE_INETD_RPC */
static void bump_nofile(void)
{
enum { FD_CHUNK = 32 };
struct rlimit rl;
/* Never fails under Linux (except if you pass it bad arguments) */
getrlimit(RLIMIT_NOFILE, &rl);
rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
if (rl.rlim_cur <= rlim_ofile_cur) {
bb_error_msg("can't extend file limit, max = %d",
(int) rl.rlim_cur);
return;
}
if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
bb_perror_msg("setrlimit");
return;
}
rlim_ofile_cur = rl.rlim_cur;
}
static void remove_fd_from_set(int fd)
{
if (fd >= 0) {
FD_CLR(fd, &allsock);
dbg("stopped listening on fd:%d\n", fd);
maxsock = -1;
dbg("maxsock:%d\n", maxsock);
}
}
static void add_fd_to_set(int fd)
{
if (fd >= 0) {
FD_SET(fd, &allsock);
dbg("started listening on fd:%d\n", fd);
if (maxsock >= 0 && fd > maxsock) {
prev_maxsock = maxsock = fd;
dbg("maxsock:%d\n", maxsock);
if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
bump_nofile();
}
}
}
static void recalculate_maxsock(void)
{
int fd = 0;
/* We may have no services, in this case maxsock should still be >= 0
* (code elsewhere is not happy with maxsock == -1) */
maxsock = 0;
while (fd <= prev_maxsock) {
if (FD_ISSET(fd, &allsock))
maxsock = fd;
fd++;
}
dbg("recalculated maxsock:%d\n", maxsock);
prev_maxsock = maxsock;
if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
bump_nofile();
}
static void prepare_socket_fd(servtab_t *sep)
{
int r, fd;
fd = socket(sep->se_family, sep->se_socktype, 0);
if (fd < 0) {
bb_perror_msg("socket");
return;
}
setsockopt_reuseaddr(fd);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep)) {
struct passwd *pwd;
/* zero out the port for all RPC services; let bind()
* find one. */
set_nport(&sep->se_lsa->u.sa, 0);
/* for RPC services, attempt to use a reserved port
* if they are going to be running as root. */
if (real_uid == 0 && sep->se_family == AF_INET
&& (pwd = getpwnam(sep->se_user)) != NULL
&& pwd->pw_uid == 0
) {
r = bindresvport(fd, &sep->se_lsa->u.sin);
} else {
r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
}
if (r == 0) {
int saveerrno = errno;
/* update lsa with port# */
getsockname(fd, &sep->se_lsa->u.sa, &sep->se_lsa->len);
errno = saveerrno;
}
} else
#endif
{
if (sep->se_family == AF_UNIX) {
struct sockaddr_un *sun;
sun = (struct sockaddr_un*)&(sep->se_lsa->u.sa);
unlink(sun->sun_path);
}
r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
}
if (r < 0) {
bb_perror_msg("%s/%s: bind",
sep->se_service, sep->se_proto);
close(fd);
rearm_alarm();
return;
}
if (sep->se_socktype == SOCK_STREAM) {
listen(fd, global_queuelen);
dbg("new sep->se_fd:%d (stream)\n", fd);
} else {
dbg("new sep->se_fd:%d (!stream)\n", fd);
}
add_fd_to_set(fd);
sep->se_fd = fd;
}
static int reopen_config_file(void)
{
free(default_local_hostname);
default_local_hostname = xstrdup("*");
if (parser != NULL)
config_close(parser);
parser = config_open(config_filename);
return (parser != NULL);
}
static void close_config_file(void)
{
if (parser) {
config_close(parser);
parser = NULL;
}
}
static void free_servtab_strings(servtab_t *cp)
{
int i;
free(cp->se_local_hostname);
free(cp->se_service);
free(cp->se_proto);
free(cp->se_user);
free(cp->se_group);
free(cp->se_lsa); /* not a string in fact */
free(cp->se_program);
for (i = 0; i < MAXARGV; i++)
free(cp->se_argv[i]);
}
static servtab_t *new_servtab(void)
{
servtab_t *newtab = xzalloc(sizeof(servtab_t));
newtab->se_fd = -1; /* paranoia */
return newtab;
}
static servtab_t *dup_servtab(servtab_t *sep)
{
servtab_t *newtab;
int argc;
newtab = new_servtab();
*newtab = *sep; /* struct copy */
/* deep-copying strings */
newtab->se_service = xstrdup(newtab->se_service);
newtab->se_proto = xstrdup(newtab->se_proto);
newtab->se_user = xstrdup(newtab->se_user);
newtab->se_group = xstrdup(newtab->se_group);
newtab->se_program = xstrdup(newtab->se_program);
for (argc = 0; argc <= MAXARGV; argc++)
newtab->se_argv[argc] = xstrdup(newtab->se_argv[argc]);
/* NB: se_fd, se_hostaddr and se_next are always
* overwrittend by callers, so we don't bother resetting them
* to NULL/0/-1 etc */
return newtab;
}
/* gcc generates much more code if this is inlined */
static NOINLINE servtab_t *parse_one_line(void)
{
int argc;
char *token[6+MAXARGV];
char *p, *arg;
char *hostdelim;
servtab_t *sep;
servtab_t *nsep;
new:
sep = new_servtab();
more:
argc = config_read(parser, token, 6+MAXARGV, 1, "# \t", PARSE_NORMAL);
if (!argc) {
free(sep);
return NULL;
}
/* [host:]service socktype proto wait user[:group] prog [args] */
/* Check for "host:...." line */
arg = token[0];
hostdelim = strrchr(arg, ':');
if (hostdelim) {
*hostdelim = '\0';
sep->se_local_hostname = xstrdup(arg);
arg = hostdelim + 1;
if (*arg == '\0' && argc == 1) {
/* Line has just "host:", change the
* default host for the following lines. */
free(default_local_hostname);
default_local_hostname = sep->se_local_hostname;
/*sep->se_local_hostname = NULL; - redundant */
/* (we'll overwrite this field anyway) */
goto more;
}
} else
sep->se_local_hostname = xstrdup(default_local_hostname);
/* service socktype proto wait user[:group] prog [args] */
sep->se_service = xstrdup(arg);
/* socktype proto wait user[:group] prog [args] */
if (argc < 6) {
parse_err:
bb_error_msg("parse error on line %u, line is ignored",
parser->lineno);
/* Just "goto more" can make sep to carry over e.g.
* "rpc"-ness (by having se_rpcver_lo != 0).
* We will be more paranoid: */
free_servtab_strings(sep);
free(sep);
goto new;
}
{
static const int8_t SOCK_xxx[] ALIGN1 = {
-1,
SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
SOCK_SEQPACKET, SOCK_RAW
};
sep->se_socktype = SOCK_xxx[1 + index_in_strings(
"stream""\0" "dgram""\0" "rdm""\0"
"seqpacket""\0" "raw""\0"
, token[1])];
}
/* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
sep->se_proto = arg = xstrdup(token[2]);
if (strcmp(arg, "unix") == 0) {
sep->se_family = AF_UNIX;
} else {
char *six;
sep->se_family = AF_INET;
six = last_char_is(arg, '6');
if (six) {
#if ENABLE_FEATURE_IPV6
*six = '\0';
sep->se_family = AF_INET6;
#else
bb_error_msg("%s: no support for IPv6", sep->se_proto);
goto parse_err;
#endif
}
if (is_prefixed_with(arg, "rpc/")) {
#if ENABLE_FEATURE_INETD_RPC
unsigned n;
arg += 4;
p = strchr(sep->se_service, '/');
if (p == NULL) {
bb_error_msg("no rpc version: '%s'", sep->se_service);
goto parse_err;
}
*p++ = '\0';
n = bb_strtou(p, &p, 10);
if (n > INT_MAX) {
bad_ver_spec:
bb_error_msg("bad rpc version");
goto parse_err;
}
sep->se_rpcver_lo = sep->se_rpcver_hi = n;
if (*p == '-') {
p++;
n = bb_strtou(p, &p, 10);
if (n > INT_MAX || (int)n < sep->se_rpcver_lo)
goto bad_ver_spec;
sep->se_rpcver_hi = n;
}
if (*p != '\0')
goto bad_ver_spec;
#else
bb_error_msg("no support for rpc services");
goto parse_err;
#endif
}
/* we don't really need getprotobyname()! */
if (strcmp(arg, "tcp") == 0)
sep->se_proto_no = IPPROTO_TCP; /* = 6 */
if (strcmp(arg, "udp") == 0)
sep->se_proto_no = IPPROTO_UDP; /* = 17 */
if (six)
*six = '6';
if (!sep->se_proto_no) /* not tcp/udp?? */
goto parse_err;
}
/* [no]wait[.max] user[:group] prog [args] */
arg = token[3];
sep->se_max = max_concurrency;
p = strchr(arg, '.');
if (p) {
*p++ = '\0';
sep->se_max = bb_strtou(p, NULL, 10);
if (errno)
goto parse_err;
}
sep->se_wait = (arg[0] != 'n' || arg[1] != 'o');
if (!sep->se_wait) /* "no" seen */
arg += 2;
if (strcmp(arg, "wait") != 0)
goto parse_err;
/* user[:group] prog [args] */
sep->se_user = xstrdup(token[4]);
arg = strchr(sep->se_user, '.');
if (arg == NULL)
arg = strchr(sep->se_user, ':');
if (arg) {
*arg++ = '\0';
sep->se_group = xstrdup(arg);
}
/* prog [args] */
sep->se_program = xstrdup(token[5]);
#ifdef INETD_BUILTINS_ENABLED
if (strcmp(sep->se_program, "internal") == 0
&& strlen(sep->se_service) <= 7
&& (sep->se_socktype == SOCK_STREAM
|| sep->se_socktype == SOCK_DGRAM)
) {
unsigned i;
for (i = 0; i < ARRAY_SIZE(builtins); i++)
if (strncmp(builtins[i].bi_service7, sep->se_service, 7) == 0)
goto found_bi;
bb_error_msg("unknown internal service %s", sep->se_service);
goto parse_err;
found_bi:
sep->se_builtin = &builtins[i];
/* stream builtins must be "nowait", dgram must be "wait" */
if (sep->se_wait != (sep->se_socktype == SOCK_DGRAM))
goto parse_err;
}
#endif
argc = 0;
while (argc < MAXARGV && (arg = token[6+argc]) != NULL)
sep->se_argv[argc++] = xstrdup(arg);
/* Some inetd.conf files have no argv's, not even argv[0].
* Fix them up.
* (Technically, programs can be execed with argv[0] = NULL,
* but many programs do not like that at all) */
if (argc == 0)
sep->se_argv[0] = xstrdup(sep->se_program);
/* catch mixups. "<service> stream udp ..." == wtf */
if (sep->se_socktype == SOCK_STREAM) {
if (sep->se_proto_no == IPPROTO_UDP)
goto parse_err;
}
if (sep->se_socktype == SOCK_DGRAM) {
if (sep->se_proto_no == IPPROTO_TCP)
goto parse_err;
}
//bb_error_msg(
// "ENTRY[%s][%s][%s][%d][%d][%d][%d][%d][%s][%s][%s]",
// sep->se_local_hostname, sep->se_service, sep->se_proto, sep->se_wait, sep->se_proto_no,
// sep->se_max, sep->se_count, sep->se_time, sep->se_user, sep->se_group, sep->se_program);
/* check if the hostname specifier is a comma separated list
* of hostnames. we'll make new entries for each address. */
while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
nsep = dup_servtab(sep);
/* NUL terminate the hostname field of the existing entry,
* and make a dup for the new entry. */
*hostdelim++ = '\0';
nsep->se_local_hostname = xstrdup(hostdelim);
nsep->se_next = sep->se_next;
sep->se_next = nsep;
}
/* was doing it here: */
/* DNS resolution, create copies for each IP address */
/* IPv6-ization destroyed it :( */
return sep;
}
static servtab_t *insert_in_servlist(servtab_t *cp)
{
servtab_t *sep;
sigset_t omask;
sep = new_servtab();
*sep = *cp; /* struct copy */
sep->se_fd = -1;
#if ENABLE_FEATURE_INETD_RPC
sep->se_rpcprog = -1;
#endif
block_CHLD_HUP_ALRM(&omask);
sep->se_next = serv_list;
serv_list = sep;
restore_sigmask(&omask);
return sep;
}
static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
{
if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
return 0;
if (strcmp(old->se_service, new->se_service) != 0)
return 0;
if (strcmp(old->se_proto, new->se_proto) != 0)
return 0;
return 1;
}
static void reread_config_file(int sig UNUSED_PARAM)
{
servtab_t *sep, *cp, **sepp;
len_and_sockaddr *lsa;
sigset_t omask;
unsigned n;
uint16_t port;
int save_errno = errno;
if (!reopen_config_file())
goto ret;
for (sep = serv_list; sep; sep = sep->se_next)
sep->se_checked = 0;
goto first_line;
while (1) {
if (cp == NULL) {
first_line:
cp = parse_one_line();
if (cp == NULL)
break;
}
for (sep = serv_list; sep; sep = sep->se_next)
if (same_serv_addr_proto(sep, cp))
goto equal_servtab;
/* not an "equal" servtab */
sep = insert_in_servlist(cp);
goto after_check;
equal_servtab:
{
int i;
block_CHLD_HUP_ALRM(&omask);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep))
unregister_rpc(sep);
sep->se_rpcver_lo = cp->se_rpcver_lo;
sep->se_rpcver_hi = cp->se_rpcver_hi;
#endif
if (cp->se_wait == 0) {
/* New config says "nowait". If old one
* was "wait", we currently may be waiting
* for a child (and not accepting connects).
* Stop waiting, start listening again.
* (if it's not true, this op is harmless) */
add_fd_to_set(sep->se_fd);
}
sep->se_wait = cp->se_wait;
sep->se_max = cp->se_max;
/* string fields need more love - we don't want to leak them */
#define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
SWAP(char*, sep->se_user, cp->se_user);
SWAP(char*, sep->se_group, cp->se_group);
SWAP(char*, sep->se_program, cp->se_program);
for (i = 0; i < MAXARGV; i++)
SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
#undef SWAP
restore_sigmask(&omask);
free_servtab_strings(cp);
}
after_check:
/* cp->string_fields are consumed by insert_in_servlist()
* or freed at this point, cp itself is not yet freed. */
sep->se_checked = 1;
/* create new len_and_sockaddr */
switch (sep->se_family) {
struct sockaddr_un *sun;
case AF_UNIX:
lsa = xzalloc_lsa(AF_UNIX);
sun = (struct sockaddr_un*)&lsa->u.sa;
safe_strncpy(sun->sun_path, sep->se_service, sizeof(sun->sun_path));
break;
default: /* case AF_INET, case AF_INET6 */
n = bb_strtou(sep->se_service, NULL, 10);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep)) {
sep->se_rpcprog = n;
if (errno) { /* se_service is not numeric */
struct rpcent *rp = getrpcbyname(sep->se_service);
if (rp == NULL) {
bb_error_msg("%s: unknown rpc service", sep->se_service);
goto next_cp;
}
sep->se_rpcprog = rp->r_number;
}
if (sep->se_fd == -1)
prepare_socket_fd(sep);
if (sep->se_fd != -1)
register_rpc(sep);
goto next_cp;
}
#endif
/* what port to listen on? */
port = htons(n);
if (errno || n > 0xffff) { /* se_service is not numeric */
char protoname[4];
struct servent *sp;
/* can result only in "tcp" or "udp": */
safe_strncpy(protoname, sep->se_proto, 4);
sp = getservbyname(sep->se_service, protoname);
if (sp == NULL) {
bb_error_msg("%s/%s: unknown service",
sep->se_service, sep->se_proto);
goto next_cp;
}
port = sp->s_port;
}
if (LONE_CHAR(sep->se_local_hostname, '*')) {
lsa = xzalloc_lsa(sep->se_family);
set_nport(&lsa->u.sa, port);
} else {
lsa = host_and_af2sockaddr(sep->se_local_hostname,
ntohs(port), sep->se_family);
if (!lsa) {
bb_error_msg("%s/%s: unknown host '%s'",
sep->se_service, sep->se_proto,
sep->se_local_hostname);
goto next_cp;
}
}
break;
} /* end of "switch (sep->se_family)" */
/* did lsa change? Then close/open */
if (sep->se_lsa == NULL
|| lsa->len != sep->se_lsa->len
|| memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
) {
remove_fd_from_set(sep->se_fd);
maybe_close(sep->se_fd);
free(sep->se_lsa);
sep->se_lsa = lsa;
sep->se_fd = -1;
} else {
free(lsa);
}
if (sep->se_fd == -1)
prepare_socket_fd(sep);
next_cp:
sep = cp->se_next;
free(cp);
cp = sep;
} /* end of "while (1) parse lines" */
close_config_file();
/* Purge anything not looked at above - these are stale entries,
* new config file doesnt have them. */
block_CHLD_HUP_ALRM(&omask);
sepp = &serv_list;
while ((sep = *sepp) != NULL) {
if (sep->se_checked) {
sepp = &sep->se_next;
continue;
}
*sepp = sep->se_next;
remove_fd_from_set(sep->se_fd);
maybe_close(sep->se_fd);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep))
unregister_rpc(sep);
#endif
if (sep->se_family == AF_UNIX)
unlink(sep->se_service);
free_servtab_strings(sep);
free(sep);
}
restore_sigmask(&omask);
ret:
errno = save_errno;
}
static void reap_child(int sig UNUSED_PARAM)
{
pid_t pid;
int status;
servtab_t *sep;
int save_errno = errno;
for (;;) {
pid = wait_any_nohang(&status);
if (pid <= 0)
break;
for (sep = serv_list; sep; sep = sep->se_next) {
if (sep->se_wait != pid)
continue;
/* One of our "wait" services */
if (WIFEXITED(status) && WEXITSTATUS(status))
bb_error_msg("%s: exit status %u",
sep->se_program, WEXITSTATUS(status));
else if (WIFSIGNALED(status))
bb_error_msg("%s: exit signal %u",
sep->se_program, WTERMSIG(status));
sep->se_wait = 1;
add_fd_to_set(sep->se_fd);
break;
}
}
errno = save_errno;
}
static void retry_network_setup(int sig UNUSED_PARAM)
{
int save_errno = errno;
servtab_t *sep;
alarm_armed = 0;
for (sep = serv_list; sep; sep = sep->se_next) {
if (sep->se_fd == -1) {
prepare_socket_fd(sep);
#if ENABLE_FEATURE_INETD_RPC
if (sep->se_fd != -1 && is_rpc_service(sep))
register_rpc(sep);
#endif
}
}
errno = save_errno;
}
static void clean_up_and_exit(int sig UNUSED_PARAM)
{
servtab_t *sep;
/* XXX signal race walking sep list */
for (sep = serv_list; sep; sep = sep->se_next) {
if (sep->se_fd == -1)
continue;
switch (sep->se_family) {
case AF_UNIX:
unlink(sep->se_service);
break;
default: /* case AF_INET, AF_INET6 */
#if ENABLE_FEATURE_INETD_RPC
if (sep->se_wait == 1 && is_rpc_service(sep))
unregister_rpc(sep); /* XXX signal race */
#endif
break;
}
if (ENABLE_FEATURE_CLEAN_UP)
close(sep->se_fd);
}
remove_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
exit(EXIT_SUCCESS);
}
int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int inetd_main(int argc UNUSED_PARAM, char **argv)
{
struct sigaction sa, saved_pipe_handler;
servtab_t *sep, *sep2;
struct passwd *pwd;
struct group *grp = grp; /* for compiler */
int opt;
pid_t pid;
sigset_t omask;
INIT_G();
real_uid = getuid();
if (real_uid != 0) /* run by non-root user */
config_filename = NULL;
/* -q N, -R N */
opt = getopt32(argv, "R:+feq:+", &max_concurrency, &global_queuelen);
argv += optind;
//argc -= optind;
if (argv[0])
config_filename = argv[0];
if (config_filename == NULL)
bb_error_msg_and_die("non-root must specify config file");
if (!(opt & 2))
bb_daemonize_or_rexec(0, argv - optind);
else
bb_sanitize_stdio();
if (!(opt & 4)) {
/* LOG_NDELAY: connect to syslog daemon NOW.
* Otherwise, we may open syslog socket
* in vforked child, making opened fds and syslog()
* internal state inconsistent.
* This was observed to leak file descriptors. */
openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
logmode = LOGMODE_SYSLOG;
}
if (real_uid == 0) {
/* run by root, ensure groups vector gets trashed */
gid_t gid = getgid();
setgroups(1, &gid);
}
write_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
/* never fails under Linux (except if you pass it bad arguments) */
getrlimit(RLIMIT_NOFILE, &rlim_ofile);
rlim_ofile_cur = rlim_ofile.rlim_cur;
if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
rlim_ofile_cur = OPEN_MAX;
memset(&sa, 0, sizeof(sa));
/*sigemptyset(&sa.sa_mask); - memset did it */
sigaddset(&sa.sa_mask, SIGALRM);
sigaddset(&sa.sa_mask, SIGCHLD);
sigaddset(&sa.sa_mask, SIGHUP);
//FIXME: explain why no SA_RESTART
//FIXME: retry_network_setup is unsafe to run in signal handler (many reasons)!
sa.sa_handler = retry_network_setup;
sigaction_set(SIGALRM, &sa);
//FIXME: reread_config_file is unsafe to run in signal handler(many reasons)!
sa.sa_handler = reread_config_file;
sigaction_set(SIGHUP, &sa);
//FIXME: reap_child is unsafe to run in signal handler (uses stdio)!
sa.sa_handler = reap_child;
sigaction_set(SIGCHLD, &sa);
//FIXME: clean_up_and_exit is unsafe to run in signal handler (uses stdio)!
sa.sa_handler = clean_up_and_exit;
sigaction_set(SIGTERM, &sa);
sa.sa_handler = clean_up_and_exit;
sigaction_set(SIGINT, &sa);
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, &saved_pipe_handler);
reread_config_file(SIGHUP); /* load config from file */
for (;;) {
int ready_fd_cnt;
int ctrl, accepted_fd, new_udp_fd;
fd_set readable;
if (maxsock < 0)
recalculate_maxsock();
readable = allsock; /* struct copy */
/* if there are no fds to wait on, we will block
* until signal wakes us up (maxsock == 0, but readable
* never contains fds 0 and 1...) */
ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
if (ready_fd_cnt < 0) {
if (errno != EINTR) {
bb_perror_msg("select");
sleep(1);
}
continue;
}
dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
continue;
dbg("ready fd:%d\n", sep->se_fd);
ready_fd_cnt--;
ctrl = sep->se_fd;
accepted_fd = -1;
new_udp_fd = -1;
if (!sep->se_wait) {
if (sep->se_socktype == SOCK_STREAM) {
ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
dbg("accepted_fd:%d\n", accepted_fd);
if (ctrl < 0) {
if (errno != EINTR)
bb_perror_msg("accept (for %s)", sep->se_service);
continue;
}
}
/* "nowait" udp */
if (sep->se_socktype == SOCK_DGRAM
&& sep->se_family != AF_UNIX
) {
/* How udp "nowait" works:
* child peeks at (received and buffered by kernel) UDP packet,
* performs connect() on the socket so that it is linked only
* to this peer. But this also affects parent, because descriptors
* are shared after fork() a-la dup(). When parent performs
* select(), it will see this descriptor connected to the peer (!)
* and still readable, will act on it and mess things up
* (can create many copies of same child, etc).
* Parent must create and use new socket instead. */
new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
dbg("new_udp_fd:%d\n", new_udp_fd);
if (new_udp_fd < 0) { /* error: eat packet, forget about it */
udp_err:
recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
continue;
}
setsockopt_reuseaddr(new_udp_fd);
/* TODO: better do bind after fork in parent,
* so that we don't have two wildcard bound sockets
* even for a brief moment? */
if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
dbg("bind(new_udp_fd) failed\n");
close(new_udp_fd);
goto udp_err;
}
dbg("bind(new_udp_fd) succeeded\n");
}
}
block_CHLD_HUP_ALRM(&omask);
pid = 0;
#ifdef INETD_BUILTINS_ENABLED
/* do we need to fork? */
if (sep->se_builtin == NULL
|| (sep->se_socktype == SOCK_STREAM
&& sep->se_builtin->bi_fork))
#endif
{
if (sep->se_max != 0) {
if (++sep->se_count == 1)
sep->se_time = monotonic_sec();
else if (sep->se_count >= sep->se_max) {
unsigned now = monotonic_sec();
/* did we accumulate se_max connects too quickly? */
if (now - sep->se_time <= CNT_INTERVAL) {
bb_error_msg("%s/%s: too many connections, pausing",
sep->se_service, sep->se_proto);
remove_fd_from_set(sep->se_fd);
close(sep->se_fd);
sep->se_fd = -1;
sep->se_count = 0;
rearm_alarm(); /* will revive it in RETRYTIME sec */
restore_sigmask(&omask);
maybe_close(new_udp_fd);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
sep->se_count = 0;
}
}
/* on NOMMU, streamed chargen
* builtin wouldn't work, but it is
* not allowed on NOMMU (ifdefed out) */
#ifdef INETD_BUILTINS_ENABLED
if (BB_MMU && sep->se_builtin)
pid = fork();
else
#endif
pid = vfork();
if (pid < 0) { /* fork error */
bb_perror_msg("vfork"+1);
sleep(1);
restore_sigmask(&omask);
maybe_close(new_udp_fd);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
if (pid == 0)
pid--; /* -1: "we did fork and we are child" */
}
/* if pid == 0 here, we didn't fork */
if (pid > 0) { /* parent */
if (sep->se_wait) {
/* wait: we passed socket to child,
* will wait for child to terminate */
sep->se_wait = pid;
remove_fd_from_set(sep->se_fd);
}
if (new_udp_fd >= 0) {
/* udp nowait: child connected the socket,
* we created and will use new, unconnected one */
xmove_fd(new_udp_fd, sep->se_fd);
dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
}
restore_sigmask(&omask);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
/* we are either child or didn't fork at all */
#ifdef INETD_BUILTINS_ENABLED
if (sep->se_builtin) {
if (pid) { /* "pid" is -1: we did fork */
close(sep->se_fd); /* listening socket */
dbg("closed sep->se_fd:%d\n", sep->se_fd);
logmode = LOGMODE_NONE; /* make xwrite etc silent */
}
restore_sigmask(&omask);
if (sep->se_socktype == SOCK_STREAM)
sep->se_builtin->bi_stream_fn(ctrl, sep);
else
sep->se_builtin->bi_dgram_fn(ctrl, sep);
if (pid) /* we did fork */
_exit(EXIT_FAILURE);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
#endif
/* child */
setsid();
/* "nowait" udp */
if (new_udp_fd >= 0) {
len_and_sockaddr *lsa;
int r;
close(new_udp_fd);
dbg("closed new_udp_fd:%d\n", new_udp_fd);
lsa = xzalloc_lsa(sep->se_family);
/* peek at the packet and remember peer addr */
r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
&lsa->u.sa, &lsa->len);
if (r < 0)
goto do_exit1;
/* make this socket "connected" to peer addr:
* only packets from this peer will be recv'ed,
* and bare write()/send() will work on it */
connect(ctrl, &lsa->u.sa, lsa->len);
dbg("connected ctrl:%d to remote peer\n", ctrl);
free(lsa);
}
/* prepare env and exec program */
pwd = getpwnam(sep->se_user);
if (pwd == NULL) {
bb_error_msg("%s: no such %s", sep->se_user, "user");
goto do_exit1;
}
if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
bb_error_msg("%s: no such %s", sep->se_group, "group");
goto do_exit1;
}
if (real_uid != 0 && real_uid != pwd->pw_uid) {
/* a user running private inetd */
bb_error_msg("non-root must run services as himself");
goto do_exit1;
}
if (pwd->pw_uid != 0) {
if (sep->se_group)
pwd->pw_gid = grp->gr_gid;
/* initgroups, setgid, setuid: */
change_identity(pwd);
} else if (sep->se_group) {
xsetgid(grp->gr_gid);
setgroups(1, &grp->gr_gid);
}
if (rlim_ofile.rlim_cur != rlim_ofile_cur)
if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
bb_perror_msg("setrlimit");
/* closelog(); - WRONG. we are after vfork,
* this may confuse syslog() internal state.
* Let's hope libc sets syslog fd to CLOEXEC...
*/
xmove_fd(ctrl, STDIN_FILENO);
xdup2(STDIN_FILENO, STDOUT_FILENO);
dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
/* manpages of inetd I managed to find either say
* that stderr is also redirected to the network,
* or do not talk about redirection at all (!) */
if (!sep->se_wait) /* only for usual "tcp nowait" */
xdup2(STDIN_FILENO, STDERR_FILENO);
/* NB: among others, this loop closes listening sockets
* for nowait stream children */
for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
if (sep2->se_fd != ctrl)
maybe_close(sep2->se_fd);
sigaction_set(SIGPIPE, &saved_pipe_handler);
restore_sigmask(&omask);
dbg("execing:'%s'\n", sep->se_program);
BB_EXECVP(sep->se_program, sep->se_argv);
bb_perror_msg("can't execute '%s'", sep->se_program);
do_exit1:
/* eat packet in udp case */
if (sep->se_socktype != SOCK_STREAM)
recv(0, line, LINE_SIZE, MSG_DONTWAIT);
_exit(EXIT_FAILURE);
} /* for (sep = servtab...) */
} /* for (;;) */
}
#if !BB_MMU
static const char *const cat_args[] = { "cat", NULL };
#endif
/*
* Internet services provided internally by inetd:
*/
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
/* Echo service -- echo data back. */
/* ARGSUSED */
static void FAST_FUNC echo_stream(int s, servtab_t *sep UNUSED_PARAM)
{
#if BB_MMU
while (1) {
ssize_t sz = safe_read(s, line, LINE_SIZE);
if (sz <= 0)
break;
xwrite(s, line, sz);
}
#else
/* We are after vfork here! */
/* move network socket to stdin/stdout */
xmove_fd(s, STDIN_FILENO);
xdup2(STDIN_FILENO, STDOUT_FILENO);
/* no error messages please... */
close(STDERR_FILENO);
xopen(bb_dev_null, O_WRONLY);
BB_EXECVP("cat", (char**)cat_args);
/* on failure we return to main, which does exit(EXIT_FAILURE) */
#endif
}
static void FAST_FUNC echo_dg(int s, servtab_t *sep)
{
enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
char *buf = xmalloc(BUFSIZE); /* too big for stack */
int sz;
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
lsa->len = sep->se_lsa->len;
/* dgram builtins are non-forking - DONT BLOCK! */
sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
if (sz > 0)
sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
free(buf);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
/* Discard service -- ignore data. */
/* ARGSUSED */
static void FAST_FUNC discard_stream(int s, servtab_t *sep UNUSED_PARAM)
{
#if BB_MMU
while (safe_read(s, line, LINE_SIZE) > 0)
continue;
#else
/* We are after vfork here! */
/* move network socket to stdin */
xmove_fd(s, STDIN_FILENO);
/* discard output */
close(STDOUT_FILENO);
xopen(bb_dev_null, O_WRONLY);
/* no error messages please... */
xdup2(STDOUT_FILENO, STDERR_FILENO);
BB_EXECVP("cat", (char**)cat_args);
/* on failure we return to main, which does exit(EXIT_FAILURE) */
#endif
}
/* ARGSUSED */
static void FAST_FUNC discard_dg(int s, servtab_t *sep UNUSED_PARAM)
{
/* dgram builtins are non-forking - DONT BLOCK! */
recv(s, line, LINE_SIZE, MSG_DONTWAIT);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
#define LINESIZ 72
static void init_ring(void)
{
int i;
end_ring = ring;
for (i = ' '; i < 127; i++)
*end_ring++ = i;
}
/* Character generator. MMU arches only. */
/* ARGSUSED */
static void FAST_FUNC chargen_stream(int s, servtab_t *sep UNUSED_PARAM)
{
char *rs;
int len;
char text[LINESIZ + 2];
if (!end_ring) {
init_ring();
rs = ring;
}
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
rs = ring;
for (;;) {
len = end_ring - rs;
if (len >= LINESIZ)
memmove(text, rs, LINESIZ);
else {
memmove(text, rs, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++rs == end_ring)
rs = ring;
xwrite(s, text, sizeof(text));
}
}
/* ARGSUSED */
static void FAST_FUNC chargen_dg(int s, servtab_t *sep)
{
int len;
char text[LINESIZ + 2];
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
/* Eat UDP packet which started it all */
/* dgram builtins are non-forking - DONT BLOCK! */
lsa->len = sep->se_lsa->len;
if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
return;
if (!end_ring) {
init_ring();
ring_pos = ring;
}
len = end_ring - ring_pos;
if (len >= LINESIZ)
memmove(text, ring_pos, LINESIZ);
else {
memmove(text, ring_pos, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++ring_pos == end_ring)
ring_pos = ring;
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
/*
* Return a machine readable date and time, in the form of the
* number of seconds since midnight, Jan 1, 1900. Since gettimeofday
* returns the number of seconds since midnight, Jan 1, 1970,
* we must add 2208988800 seconds to this figure to make up for
* some seventy years Bell Labs was asleep.
*/
static uint32_t machtime(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return htonl((uint32_t)(tv.tv_sec + 2208988800U));
}
/* ARGSUSED */
static void FAST_FUNC machtime_stream(int s, servtab_t *sep UNUSED_PARAM)
{
uint32_t result;
result = machtime();
full_write(s, &result, sizeof(result));
}
static void FAST_FUNC machtime_dg(int s, servtab_t *sep)
{
uint32_t result;
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
lsa->len = sep->se_lsa->len;
if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
return;
result = machtime();
sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
/* Return human-readable time of day */
/* ARGSUSED */
static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
{
time_t t;
time(&t);
fdprintf(s, "%.24s\r\n", ctime(&t));
}
static void FAST_FUNC daytime_dg(int s, servtab_t *sep)
{
time_t t;
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
lsa->len = sep->se_lsa->len;
if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
return;
t = time(NULL);
sprintf(line, "%.24s\r\n", ctime(&t));
sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */
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