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aac2a19e50
busybox/networking/inetd.c
Glenn L McGrath aac2a19e50 remove debugging
2004-02-18 12:58:00 +00:00

1213 lines
30 KiB
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/*
* Copyright (c) 1983,1991 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* David A. Holland.
*
* Busybox port by Vladimir Oleynik (C) 2001-2003 <dzo@simtreas.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*
* Inetd - Internet super-server
*
* This program invokes all internet services as needed.
* connection-oriented services are invoked each time a
* connection is made, by creating a process. This process
* is passed the connection as file descriptor 0 and is
* expected to do a getpeername to find out the source host
* and port.
*
* Datagram oriented services are invoked when a datagram
* arrives; a process is created and passed a pending message
* on file descriptor 0. Datagram servers may either connect
* to their peer, freeing up the original socket for inetd
* to receive further messages on, or ``take over the socket'',
* processing all arriving datagrams and, eventually, timing
* out. The first type of server is said to be ``multi-threaded'';
* the second type of server ``single-threaded''.
*
* Inetd uses a configuration file which is read at startup
* and, possibly, at some later time in response to a hangup signal.
* The configuration file is ``free format'' with fields given in the
* order shown below. Continuation lines for an entry must being with
* a space or tab. All fields must be present in each entry.
*
* service name must be in /etc/services
* socket type stream/dgram/raw/rdm/seqpacket
* protocol must be in /etc/protocols
* wait/nowait[.max] single-threaded/multi-threaded, max #
* user[.group] user/group to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS (20)
*
* RPC services unsuported
*
* Comment lines are indicated by a `#' in column 1.
*/
/*
* Here's the scoop concerning the user.group feature:
*
* 1) No group listed.
*
* a) for root: NO setuid() or setgid() is done
*
* b) nonroot: setuid()
* setgid(primary group as found in passwd)
* initgroups(name, primary group)
*
* 2) set-group-option on.
*
* a) for root: NO setuid()
* setgid(specified group)
* setgroups(1, specified group)
*
* b) nonroot: setuid()
* setgid(specified group)
* initgroups(name, specified group)
*
* All supplementary groups are discarded at startup in case inetd was
* run manually.
*/
#define __USE_BSD_SIGNAL
#include "busybox.h"
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#ifndef __linux__
#ifndef RLIMIT_NOFILE
#define RLIMIT_NOFILE RLIMIT_OFILE
#endif
#endif
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <errno.h>
#include <signal.h>
#include <netdb.h>
#include <syslog.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <unistd.h>
#include <stdarg.h>
#include <time.h>
#ifndef OPEN_MAX
#define OPEN_MAX 64
#endif
#define _PATH_INETDCONF "/etc/inetd.conf"
#define _PATH_INETDPID "/var/run/inetd.pid"
#define TOOMANY 40 /* don't start more than TOOMANY */
#define CNT_INTVL 60 /* servers in CNT_INTVL sec. */
#define RETRYTIME (60*10) /* retry after bind or server fail */
#define MAXARGV 20
#define se_ctrladdr se_un.se_un_ctrladdr
#define se_ctrladdr_in se_un.se_un_ctrladdr_in
#define se_ctrladdr_un se_un.se_un_ctrladdr_un
/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
#define FD_MARGIN (8)
/* Check unsupporting builtin */
#if defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO || \
defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD || \
defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME || \
defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME || \
defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
# define INETD_FEATURE_ENABLED
#endif
static struct servtab {
char *se_service; /* name of service */
int se_socktype; /* type of socket to use */
int se_family; /* address family */
char *se_proto; /* protocol used */
short se_wait; /* single threaded server */
short se_checked; /* looked at during merge */
char *se_user; /* user name to run as */
char *se_group; /* group name to run as */
#ifdef INETD_FEATURE_ENABLED
const struct biltin *se_bi; /* if built-in, description */
#endif
char *se_server; /* server program */
char *se_argv[MAXARGV+1]; /* program arguments */
int se_fd; /* open descriptor */
union {
struct sockaddr se_un_ctrladdr;
struct sockaddr_in se_un_ctrladdr_in;
struct sockaddr_un se_un_ctrladdr_un;
} se_un; /* bound address */
int se_ctrladdr_size;
int se_max; /* max # of instances of this service */
int se_count; /* number started since se_time */
struct timeval se_time; /* start of se_count */
struct servtab *se_next;
} *servtab;
#ifdef INETD_FEATURE_ENABLED
struct biltin {
const char *bi_service; /* internally provided service name */
int bi_socktype; /* type of socket supported */
short bi_fork; /* 1 if should fork before call */
short bi_wait; /* 1 if should wait for child */
void (*bi_fn)(int, struct servtab *); /* fn which performs it */
};
/* Echo received data */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
static void echo_stream(int, struct servtab *);
static void echo_dg(int, struct servtab *);
#endif
/* Internet /dev/null */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
static void discard_stream(int, struct servtab *);
static void discard_dg(int, struct servtab *);
#endif
/* Return 32 bit time since 1900 */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
static void machtime_stream(int, struct servtab *);
static void machtime_dg(int, struct servtab *);
#endif
/* Return human-readable time */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
static void daytime_stream(int, struct servtab *);
static void daytime_dg(int, struct servtab *);
#endif
/* Familiar character generator */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
static void chargen_stream(int, struct servtab *);
static void chargen_dg(int, struct servtab *);
#endif
static const struct biltin biltins[] = {
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
/* Echo received data */
{ "echo", SOCK_STREAM, 1, 0, echo_stream, },
{ "echo", SOCK_DGRAM, 0, 0, echo_dg, },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
/* Internet /dev/null */
{ "discard", SOCK_STREAM, 1, 0, discard_stream, },
{ "discard", SOCK_DGRAM, 0, 0, discard_dg, },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
/* Return 32 bit time since 1900 */
{ "time", SOCK_STREAM, 0, 0, machtime_stream, },
{ "time", SOCK_DGRAM, 0, 0, machtime_dg, },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
/* Return human-readable time */
{ "daytime", SOCK_STREAM, 0, 0, daytime_stream, },
{ "daytime", SOCK_DGRAM, 0, 0, daytime_dg, },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
/* Familiar character generator */
{ "chargen", SOCK_STREAM, 1, 0, chargen_stream, },
{ "chargen", SOCK_DGRAM, 0, 0, chargen_dg, },
#endif
{ NULL, 0, 0, 0, NULL }
};
#endif /* INETD_FEATURE_ENABLED */
#ifdef RLIMIT_NOFILE
static struct rlimit rlim_ofile;
#endif
/* Length of socket listen queue. Should be per-service probably. */
static int global_queuelen = 128;
static FILE *fconfig;
static sigset_t blockmask;
static sigset_t emptymask;
static fd_set allsock;
static int nsock;
static int maxsock;
static int timingout;
static int rlim_ofile_cur = OPEN_MAX;
static const char *CONFIG = _PATH_INETDCONF;
static void
syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
__attribute__ ((noreturn, format (printf, 2, 3)));
static void
syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
{
char buf[50];
va_list p;
va_start(p, msg);
vsyslog(LOG_ERR, msg, p);
if (se_socktype != SOCK_STREAM)
recv(0, buf, sizeof (buf), 0);
_exit(1);
}
static struct servtab *getconfigent(void)
{
static struct servtab serv;
struct servtab *sep = &serv;
int argc;
char *cp = NULL;
char *cp_ptr;
char *cp_ptr_ptr = NULL;
more:
free(cp);
cp = bb_get_chomped_line_from_file(fconfig);
if (feof(fconfig)) {
free(cp);
return (NULL);
}
if ((cp == NULL) || (*cp == '#')) {
goto more;
}
cp_ptr = strtok_r(cp, " \t", &cp_ptr_ptr);
if (cp_ptr == NULL) {
/* Error */
goto more;
}
sep->se_service = bb_xstrdup(cp_ptr);
cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
if (cp_ptr == NULL) {
/* Error */
goto more;
}
if (strcmp(cp_ptr, "stream") == 0)
sep->se_socktype = SOCK_STREAM;
else if (strcmp(cp_ptr, "dgram") == 0)
sep->se_socktype = SOCK_DGRAM;
else if (strcmp(cp_ptr, "rdm") == 0)
sep->se_socktype = SOCK_RDM;
else if (strcmp(cp_ptr, "seqpacket") == 0)
sep->se_socktype = SOCK_SEQPACKET;
else if (strcmp(cp_ptr, "raw") == 0)
sep->se_socktype = SOCK_RAW;
else
sep->se_socktype = -1;
cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
if (cp_ptr == NULL) {
/* error */
goto more;
}
if (strcmp(cp_ptr, "unix") == 0) {
sep->se_family = AF_UNIX;
} else {
if (strncmp(cp_ptr, "rpc/", 4) == 0) {
syslog(LOG_ERR, "%s: rpc services not suported",
sep->se_service);
goto more;
}
sep->se_family = AF_INET;
}
sep->se_proto = bb_xstrdup(cp_ptr);
cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
if (cp_ptr == NULL) {
/* error */
goto more;
}
{
char *s = strchr(cp_ptr, '.');
if (s) {
*s++ = '\0';
sep->se_max = atoi(s);
} else
sep->se_max = TOOMANY;
}
sep->se_wait = strcmp(cp_ptr, "wait") == 0;
cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
if (cp_ptr == NULL) {
/* error */
goto more;
}
{
char *cp_ptr2 = strchr(cp_ptr, '.');
if (cp_ptr2) {
*cp_ptr2++ = '\0';
sep->se_group = bb_xstrdup(cp_ptr2);
}
}
sep->se_user = bb_xstrdup(cp_ptr);
cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
if (cp_ptr == NULL) {
/* error */
goto more;
}
if (strcmp(cp_ptr, "internal") == 0) {
#ifdef INETD_FEATURE_ENABLED
const struct biltin *bi;
for (bi = biltins; bi->bi_service; bi++) {
if ((bi->bi_socktype == sep->se_socktype) &&
(strcmp(bi->bi_service, sep->se_service) == 0)) {
break;
}
}
if (bi->bi_service == 0) {
syslog(LOG_ERR, "internal service %s unknown", sep->se_service);
goto more;
}
sep->se_bi = bi;
sep->se_wait = bi->bi_wait;
#else
syslog(LOG_ERR, "internal service %s unknown", cp_ptr);
goto more;
#endif
}
#ifdef INETD_FEATURE_ENABLED
else {
sep->se_bi = NULL;
}
#endif
sep->se_server = bb_xstrdup(cp_ptr);
argc = 0;
while ((cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr)) != NULL) {
if (argc < MAXARGV) {
sep->se_argv[argc++] = cp_ptr;
}
}
while (argc <= MAXARGV) {
sep->se_argv[argc++] = NULL;
}
//free(cp); // BUG: cp is the argv[] container; we must not free it here!
return (sep);
}
static void freeconfig(struct servtab *cp)
{
int i;
free(cp->se_service);
free(cp->se_proto);
free(cp->se_user);
/* Note: se_group is part of the newstr'ed se_user */
free(cp->se_server);
for (i = 0; i < MAXARGV; i++)
free(cp->se_argv[i]);
}
#ifdef INETD_FEATURE_ENABLED
static char **Argv;
static char *LastArg;
static void setproctitle(char *a, int s)
{
size_t size;
char *cp;
struct sockaddr_in sn;
char buf[80];
cp = Argv[0];
size = sizeof(sn);
if (getpeername(s, (struct sockaddr *)&sn, &size) == 0)
(void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sn.sin_addr));
else
(void) sprintf(buf, "-%s", a);
strncpy(cp, buf, LastArg - cp);
cp += strlen(cp);
while (cp < LastArg)
*cp++ = ' ';
}
#endif /* INETD_FEATURE_ENABLED */
static void setup(struct servtab *sep)
{
int on = 1;
if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
syslog(LOG_ERR, "%s/%s: socket: %m",
sep->se_service, sep->se_proto);
return;
}
if (setsockopt(sep->se_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
sizeof(on)) < 0)
syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
syslog(LOG_ERR, "%s/%s: bind: %m",
sep->se_service, sep->se_proto);
(void) close(sep->se_fd);
sep->se_fd = -1;
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
return;
}
if (sep->se_socktype == SOCK_STREAM)
listen(sep->se_fd, global_queuelen);
FD_SET(sep->se_fd, &allsock);
nsock++;
if (sep->se_fd > maxsock) {
maxsock = sep->se_fd;
if (maxsock > rlim_ofile_cur - FD_MARGIN) {
#ifdef RLIMIT_NOFILE
# define FD_CHUNK 32
struct rlimit rl;
if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
syslog(LOG_ERR, "getrlimit: %m");
return;
}
rl.rlim_cur = rl.rlim_max < (rl.rlim_cur + FD_CHUNK) ? rl.rlim_max : (rl.rlim_cur + FD_CHUNK);
if (rl.rlim_cur <= rlim_ofile_cur) {
syslog(LOG_ERR,
# if _FILE_OFFSET_BITS == 64
"bump_nofile: cannot extend file limit, max = %lld",
# else
"bump_nofile: cannot extend file limit, max = %ld",
# endif
rl.rlim_cur);
return;
}
if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
syslog(LOG_ERR, "setrlimit: %m");
return;
}
rlim_ofile_cur = rl.rlim_cur;
return;
#else
syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
return;
#endif /* RLIMIT_NOFILE */
}
}
}
static void config(int signum)
{
struct servtab *sep, *cp, **sepp;
sigset_t oldmask;
unsigned n;
(void)signum;
if (fconfig != NULL) {
fseek(fconfig, 0L, L_SET);
} else {
fconfig = fopen(CONFIG, "r");
if (fconfig == NULL) {
syslog(LOG_ERR, "%s: %m", CONFIG);
return;
}
}
for (sep = servtab; sep; sep = sep->se_next)
sep->se_checked = 0;
while ((cp = getconfigent()) != NULL) {
for (sep = servtab; sep; sep = sep->se_next)
if (strcmp(sep->se_service, cp->se_service) == 0 &&
strcmp(sep->se_proto, cp->se_proto) == 0)
break;
if (sep != 0) {
int i;
#define SWAP(type, a, b) {type c=(type)a; (type)a=(type)b; (type)b=(type)c;}
sigprocmask(SIG_BLOCK, &emptymask, &oldmask);
/*
* sep->se_wait may be holding the pid of a daemon
* that we're waiting for. If so, don't overwrite
* it unless the config file explicitly says don't
* wait.
*/
if (
#ifdef INETD_FEATURE_ENABLED
cp->se_bi == 0 &&
#endif
(sep->se_wait == 1 || cp->se_wait == 0))
sep->se_wait = cp->se_wait;
if (cp->se_max != sep->se_max)
SWAP(int, cp->se_max, sep->se_max);
if (cp->se_user)
SWAP(char *, sep->se_user, cp->se_user);
if (cp->se_group)
SWAP(char *, sep->se_group, cp->se_group);
if (cp->se_server)
SWAP(char *, sep->se_server, cp->se_server);
for (i = 0; i < MAXARGV; i++)
SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
#undef SWAP
sigprocmask(SIG_SETMASK, &oldmask, NULL);
// This freeconfig() is probably a bug, since it will try and free()
// each of the argv[] values, which are really just pointers
// into the middle of a single line buffer for the config file.
//freeconfig(cp); // BUG?
} else {
sep = (struct servtab *)xmalloc(sizeof (*sep));
*sep = *cp;
sep->se_fd = -1;
sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
sep->se_next = servtab;
servtab = sep;
sigprocmask(SIG_SETMASK, &oldmask, NULL);
}
sep->se_checked = 1;
switch (sep->se_family) {
case AF_UNIX:
if (sep->se_fd != -1)
break;
(void)unlink(sep->se_service);
n = strlen(sep->se_service);
if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
sep->se_ctrladdr_un.sun_family = AF_UNIX;
sep->se_ctrladdr_size = n +
sizeof sep->se_ctrladdr_un.sun_family;
setup(sep);
break;
case AF_INET:
sep->se_ctrladdr_in.sin_family = AF_INET;
sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
{
u_short port = bb_lookup_port(sep->se_service, sep->se_proto, 0);
if (port == 0) {
syslog(LOG_ERR,
"%s/%s: unknown service",
sep->se_service, sep->se_proto);
continue;
}
if (port != sep->se_ctrladdr_in.sin_port) {
sep->se_ctrladdr_in.sin_port = port;
if (sep->se_fd != -1) {
FD_CLR(sep->se_fd, &allsock);
nsock--;
(void) close(sep->se_fd);
}
sep->se_fd = -1;
}
if (sep->se_fd == -1)
setup(sep);
}
}
}
if (fconfig) {
(void) fclose(fconfig);
fconfig = NULL;
}
/*
* Purge anything not looked at above.
*/
sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
sepp = &servtab;
while ((sep = *sepp) != NULL) {
if (sep->se_checked) {
sepp = &sep->se_next;
continue;
}
*sepp = sep->se_next;
if (sep->se_fd != -1) {
FD_CLR(sep->se_fd, &allsock);
nsock--;
(void) close(sep->se_fd);
}
if (sep->se_family == AF_UNIX)
(void)unlink(sep->se_service);
freeconfig(sep);
free((char *)sep);
}
sigprocmask(SIG_SETMASK, &oldmask, NULL);
}
static void reapchild(int signum)
{
int status;
int pid;
struct servtab *sep;
(void)signum;
for (;;) {
pid = wait3(&status, WNOHANG, (struct rusage *)0);
if (pid <= 0)
break;
for (sep = servtab; sep; sep = sep->se_next)
if (sep->se_wait == pid) {
if (WIFEXITED(status) && WEXITSTATUS(status))
syslog(LOG_WARNING,
"%s: exit status 0x%x",
sep->se_server, WEXITSTATUS(status));
else if (WIFSIGNALED(status))
syslog(LOG_WARNING,
"%s: exit signal 0x%x",
sep->se_server, WTERMSIG(status));
sep->se_wait = 1;
FD_SET(sep->se_fd, &allsock);
nsock++;
}
}
}
static void retry(int signum)
{
struct servtab *sep;
(void)signum;
timingout = 0;
for (sep = servtab; sep; sep = sep->se_next) {
if (sep->se_fd == -1) {
switch (sep->se_family) {
case AF_UNIX:
case AF_INET:
setup(sep);
break;
}
}
}
}
static void goaway(int signum)
{
struct servtab *sep;
(void)signum;
for (sep = servtab; sep; sep = sep->se_next)
if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
(void)unlink(sep->se_service);
(void)unlink(_PATH_INETDPID);
exit(0);
}
extern int inetd_main(int argc, char *argv[])
{
struct servtab *sep;
struct group *grp = NULL;
struct sigaction sa;
int pid;
unsigned long opt;
char *sq;
gid_t gid;
#ifdef INETD_FEATURE_ENABLED
extern char **environ;
#endif
gid = getgid();
setgroups(1, &gid);
#ifdef INETD_FEATURE_ENABLED
Argv = argv;
if (environ == 0 || *environ == 0)
environ = argv;
while (*environ)
environ++;
LastArg = environ[-1] + strlen(environ[-1]);
#endif
#if defined(__uClinux__)
opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
if (!(opt & 2)) {
daemon(0, 0);
/* reexec for vfork() do continue parent */
vfork_daemon_rexec(argc, argv, "-f");
}
#else
opt = bb_getopt_ulflags(argc, argv, "q:", &sq);
daemon(0, 0);
#endif /* uClinux */
if(opt & 1) {
global_queuelen = atoi(optarg);
if (global_queuelen < 8) global_queuelen=8;
}
argc -= optind;
argv += optind;
if (argc > 0)
CONFIG = argv[0];
openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
{
FILE *fp;
if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
fprintf(fp, "%u\n", getpid());
(void)fclose(fp);
}
}
#ifdef RLIMIT_NOFILE
if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
syslog(LOG_ERR, "getrlimit: %m");
} else {
rlim_ofile_cur = rlim_ofile.rlim_cur;
if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
rlim_ofile_cur = OPEN_MAX;
}
#endif
config(0);
sigemptyset(&emptymask);
sigemptyset(&blockmask);
sigaddset(&blockmask, SIGCHLD);
sigaddset(&blockmask, SIGHUP);
sigaddset(&blockmask, SIGALRM);
memset(&sa, 0, sizeof(sa));
sa.sa_mask = blockmask;
sa.sa_handler = retry;
sigaction(SIGALRM, &sa, NULL);
sa.sa_handler = config;
sigaction(SIGHUP, &sa, NULL);
sa.sa_handler = reapchild;
sigaction(SIGCHLD, &sa, NULL);
sa.sa_handler = goaway;
sigaction(SIGTERM, &sa, NULL);
sa.sa_handler = goaway;
sigaction(SIGINT, &sa, NULL);
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, NULL);
{
/* space for daemons to overwrite environment for ps */
#define DUMMYSIZE 100
char dummy[DUMMYSIZE];
(void)memset(dummy, 'x', DUMMYSIZE - 1);
dummy[DUMMYSIZE - 1] = '\0';
(void)setenv("inetd_dummy", dummy, 1);
}
for (;;) {
int n, ctrl;
fd_set readable;
if (nsock == 0) {
sigprocmask(SIG_BLOCK, &blockmask, NULL);
while (nsock == 0)
sigsuspend(&emptymask);
sigprocmask(SIG_SETMASK, &emptymask, NULL);
}
readable = allsock;
if ((n = select(maxsock + 1, &readable, (fd_set *)0,
(fd_set *)0, (struct timeval *)0)) <= 0) {
if (n < 0 && errno != EINTR)
syslog(LOG_WARNING, "select: %m");
sleep(1);
continue;
}
for (sep = servtab; n && sep; sep = sep->se_next)
if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
n--;
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
/* Fixed AGC */
fcntl(sep->se_fd, F_SETFL, O_NDELAY);
/* --------- */
ctrl = accept(sep->se_fd, NULL, NULL);
fcntl(sep->se_fd, F_SETFL, 0);
if (ctrl < 0) {
if (errno == EINTR || errno == EWOULDBLOCK)
continue;
syslog(LOG_WARNING, "accept (for %s): %m",
sep->se_service);
continue;
}
} else
ctrl = sep->se_fd;
sigprocmask(SIG_BLOCK, &blockmask, NULL);
pid = 0;
#ifdef INETD_FEATURE_ENABLED
if (sep->se_bi == 0 || sep->se_bi->bi_fork)
#endif
{
if (sep->se_count++ == 0)
(void)gettimeofday(&sep->se_time, (struct timezone *)0);
else if (sep->se_count >= sep->se_max) {
struct timeval now;
(void)gettimeofday(&now, (struct timezone *)0);
if (now.tv_sec - sep->se_time.tv_sec >
CNT_INTVL) {
sep->se_time = now;
sep->se_count = 1;
} else {
syslog(LOG_ERR,
"%s/%s server failing (looping), service terminated",
sep->se_service, sep->se_proto);
FD_CLR(sep->se_fd, &allsock);
(void) close(sep->se_fd);
sep->se_fd = -1;
sep->se_count = 0;
nsock--;
sigprocmask(SIG_SETMASK, &emptymask,
NULL);
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
continue;
}
}
pid = fork();
if (pid < 0) {
syslog(LOG_ERR, "fork: %m");
if (sep->se_socktype == SOCK_STREAM)
close(ctrl);
sigprocmask(SIG_SETMASK, &emptymask, NULL);
sleep(1);
continue;
}
if (pid && sep->se_wait) {
sep->se_wait = pid;
FD_CLR(sep->se_fd, &allsock);
nsock--;
}
}
sigprocmask(SIG_SETMASK, &emptymask, NULL);
if (pid == 0) {
#ifdef INETD_FEATURE_ENABLED
if (sep->se_bi)
(*sep->se_bi->bi_fn)(ctrl, sep);
else
#endif
{
struct passwd *pwd = getpwnam(sep->se_user);
if (pwd == NULL) {
syslog_err_and_discard_dg(
sep->se_socktype,
"getpwnam: %s: No such user",
sep->se_user);
}
if (sep->se_group &&
(grp = getgrnam(sep->se_group)) == NULL) {
syslog_err_and_discard_dg(
sep->se_socktype,
"getgrnam: %s: No such group",
sep->se_group);
}
/*
* Ok. There are four cases here:
* 1. nonroot user, no group specified
* 2. nonroot user, some group specified
* 3. root user, no group specified
* 4. root user, some group specified
* In cases 2 and 4 we setgid to the specified
* group. In cases 1 and 2 we run initgroups
* to run with the groups of the given user.
* In case 4 we do setgroups to run with the
* given group. In case 3 we do nothing.
*/
if (pwd->pw_uid) {
if (sep->se_group)
pwd->pw_gid = grp->gr_gid;
setgid((gid_t)pwd->pw_gid);
initgroups(pwd->pw_name, pwd->pw_gid);
setuid((uid_t)pwd->pw_uid);
} else if (sep->se_group) {
setgid((gid_t)grp->gr_gid);
setgroups(1, &grp->gr_gid);
}
dup2(ctrl, 0);
close(ctrl);
dup2(0, 1);
dup2(0, 2);
#ifdef RLIMIT_NOFILE
if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
if (setrlimit(RLIMIT_NOFILE,
&rlim_ofile) < 0)
syslog(LOG_ERR,"setrlimit: %m");
}
#endif
for (ctrl = rlim_ofile_cur-1; --ctrl > 2; )
(void)close(ctrl);
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sigaction(SIGPIPE, &sa, NULL);
execv(sep->se_server, sep->se_argv);
syslog_err_and_discard_dg(sep->se_socktype,
"execv %s: %m", sep->se_server);
}
}
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
close(ctrl);
}
}
}
/*
* Internet services provided internally by inetd:
*/
#define BUFSIZE 4096
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
/* Echo service -- echo data back */
static void echo_stream(int s, struct servtab *sep)
{
char buffer[BUFSIZE];
int i;
setproctitle(sep->se_service, s);
while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
write(s, buffer, i) > 0)
;
exit(0);
}
/* Echo service -- echo data back */
static void echo_dg(int s, struct servtab *sep)
{
char buffer[BUFSIZE];
int i;
size_t size;
struct sockaddr sa;
(void)sep;
size = sizeof(sa);
if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
return;
(void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
/* Discard service -- ignore data */
static void discard_stream(int s, struct servtab *sep)
{
char buffer[BUFSIZE];
setproctitle(sep->se_service, s);
while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
errno == EINTR)
;
exit(0);
}
/* Discard service -- ignore data */
static void discard_dg(int s, struct servtab *sep)
{
char buffer[BUFSIZE];
(void)sep;
read(s, buffer, sizeof(buffer));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
#include <ctype.h>
#define LINESIZ 72
static char ring[128];
static char *endring;
static void initring(void)
{
int i;
endring = ring;
for (i = 0; i <= 128; ++i)
if (isprint(i))
*endring++ = i;
}
/* Character generator */
static void chargen_stream(int s, struct servtab *sep)
{
char *rs;
int len;
char text[LINESIZ+2];
setproctitle(sep->se_service, s);
if (!endring) {
initring();
rs = ring;
}
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
for (rs = ring;;) {
if ((len = endring - rs) >= LINESIZ)
memcpy(rs, text, LINESIZ);
else {
memcpy(rs, text, len);
memcpy(ring, text + len, LINESIZ - len);
}
if (++rs == endring)
rs = ring;
if (write(s, text, sizeof(text)) != sizeof(text))
break;
}
exit(0);
}
/* Character generator */
static void chargen_dg(int s, struct servtab *sep)
{
struct sockaddr sa;
static char *rs;
size_t len, size;
char text[LINESIZ+2];
(void)sep;
if (endring == 0) {
initring();
rs = ring;
}
size = sizeof(sa);
if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
return;
if ((len = endring - rs) >= LINESIZ)
memcpy(rs, text, LINESIZ);
else {
memcpy(rs, text, len);
memcpy(ring, text + len, LINESIZ - len);
}
if (++rs == endring)
rs = ring;
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
(void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_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 long machtime(void)
{
struct timeval tv;
if (gettimeofday(&tv, (struct timezone *)0) < 0) {
fprintf(stderr, "Unable to get time of day\n");
return (0L);
}
return (htonl((long)tv.tv_sec + 2208988800UL));
}
static void machtime_stream(int s, struct servtab *sep)
{
long result;
(void)sep;
result = machtime();
write(s, (char *) &result, sizeof(result));
}
static void machtime_dg(int s, struct servtab *sep)
{
long result;
struct sockaddr sa;
size_t size;
(void)sep;
size = sizeof(sa);
if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
return;
result = machtime();
(void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
/* Return human-readable time of day */
static int human_readable_time_sprintf(char *buffer)
{
time_t clocc = time(NULL);
return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
}
static void daytime_stream(int s, struct servtab *sep)
{
char buffer[256];
size_t st = human_readable_time_sprintf(buffer);
(void)sep;
write(s, buffer, st);
}
/* Return human-readable time of day */
static void daytime_dg(int s, struct servtab *sep)
{
char buffer[256];
struct sockaddr sa;
size_t size;
(void)sep;
size = sizeof(sa);
if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
return;
size = human_readable_time_sprintf(buffer);
sendto(s, buffer, size, 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */
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