3 * $Id: daemon.c,v 1.3 1997/08/07 09:49:39 mdw Exp $
5 * Running a `become' daemon
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of `become'
14 * `Become' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `Become' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `become'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.3 1997/08/07 09:49:39 mdw
33 * Extensive modifications to handle netgroups. Also sanitise user and group
34 * names before adding them to the symbol table.
36 * Revision 1.2 1997/08/04 10:24:21 mdw
37 * Sources placed under CVS control.
39 * Revision 1.1 1997/07/21 13:47:50 mdw
44 /*----- Header files ------------------------------------------------------*/
46 /* --- ANSI headers --- */
55 /* --- Unix headers --- */
57 #include <sys/types.h>
59 #include <sys/socket.h>
61 #include <netinet/in.h>
63 #include <arpa/inet.h>
69 /* --- Local headers --- */
85 /*----- Arbitrary constants -----------------------------------------------*/
87 #define daemon__awakeEvery (30 * 60) /* Awaken this often to rescan */
89 /*----- Static variables --------------------------------------------------*/
91 static int daemon__running
= 0; /* Am I running as a daemon? */
92 static int daemon__port
= -1; /* No particular port yet */
93 static volatile sig_atomic_t daemon__rescan
= 0; /* Rescan as soon as poss */
94 #define daemon__signum daemon__rescan /* Alias for readbility */
95 static int daemon__readKey
= 0; /* Have I read a key? */
96 static unsigned char daemon__key
[IDEA_KEYSIZE
]; /* encryption key */
97 static jmp_buf daemon__dieBuf
; /* Jump here to kill the daemon */
99 /*----- Main code ---------------------------------------------------------*/
101 /* --- @daemon_usePort@ --- *
103 * Arguments: @int port@ = port to use, please
107 * Use: Instructs the daemon to listen to the given port.
110 void daemon_usePort(int port
)
115 /* --- @daemon_readKey@ --- *
117 * Arguments: @const char *kf@ = name of file containing key
121 * Use: Instructs the daemon to read the named key file.
124 void daemon_readKey(const char *kf
)
128 if (!daemon__running
)
131 if ((fp
= fopen(kf
, "r")) == 0) {
132 syslog(LOG_WARNING
, "couldn't read key file: %e");
135 tx_getBits(daemon__key
, 128, fp
);
141 /* --- @daemon__readConfig@ --- *
143 * Arguments: @const char *cf@ = pointer to configuration file to use
145 * Returns: Zero if it worked, nonzero if it hurt...
147 * Use: Reads the configuration file, and other things.
150 static int daemon__readConfig(const char *cf
)
155 if ((fp
= fopen(cf
, "r")) == 0)
160 if (!daemon__readKey
)
161 daemon_readKey(file_KEY
);
163 T( trace(TRACE_DAEMON
, "daemon: read config file"); )
167 /* --- @daemon__restart@ --- *
169 * Arguments: @int sig@ = the signal number
173 * Use: Handles signals. Causes the configuration file to be reread.
176 static void daemon__restart(int sig
)
179 signal(sig
, daemon__restart
);
182 /* --- @daemon__die@ --- *
184 * Arguments: @int sig@ = the signal number
186 * Returns: via @longjmp@
188 * Use: Handles other signals. Causes the daemon to die.
191 static void daemon__die(int sig
)
193 daemon__signum
= sig
;
194 longjmp(daemon__dieBuf
, 1);
197 /* --- @daemon__read@ --- *
199 * Arguments: @int fd@ = socket handle
203 * Use: Examines a buffer, and returns a response.
206 void daemon__read(int fd
)
208 unsigned char buff
[65536]; /* Buffer for incoming packets */
209 unsigned char rpl
[crp_size
]; /* Buffer for outgoing replies */
210 struct sockaddr_in sin
; /* Address of packet sender */
211 char sender
[64]; /* Sender's hostname (resolved) */
212 unsigned char sk
[IDEA_KEYSIZE
]; /* Session key for reply */
213 request rq
; /* Request buffer for verification */
215 /* --- Read the message --- */
218 int slen
= sizeof(sin
);
220 if (recvfrom(fd
, (char *)buff
, sizeof(buff
), 0,
221 (struct sockaddr
*)&sin
, &slen
) < 0) {
222 T( trace(TRACE_DAEMON
, "daemon: error reading packet: %s",
224 syslog(LOG_INFO
, "duff packet received: %e");
229 /* --- Resolve the host name --- */
232 struct hostent
*he
= gethostbyaddr((char *)&sin
.sin_addr
,
233 sizeof(sin
.sin_addr
),
237 he ? he
->h_name
: inet_ntoa(sin
.sin_addr
),
239 syslog(LOG_DEBUG
, "packet received from %s", sender
);
240 T( trace(TRACE_DAEMON
, "daemon: received request from %s", sender
); )
243 /* --- Unpack the block --- */
245 if (crypt_unpackRequest(&rq
, buff
, daemon__key
, sk
, rpl
) == 0) {
247 T( trace(TRACE_DAEMON
, "daemon: received corrupt or invalid request"); )
248 syslog(LOG_INFO
, "packet from %s rejected", sender
);
253 /* --- Fill in the sender's address in the request block --- */
255 rq
.host
= sin
.sin_addr
;
257 /* --- Build a reply block --- */
260 int answer
= rule_check(&rq
);
261 syslog(LOG_INFO
, "request from %s for %i to become %i to run %s %s",
262 sender
, rq
.from
, rq
.to
, rq
.cmd
, answer ?
"granted" : "denied");
263 crypt_packReply(rpl
, sk
, answer
);
267 /* --- Send the reply off --- */
269 sendto(fd
, (char *)rpl
, crp_size
, 0, (struct sockaddr
*)&sin
, sizeof(sin
));
270 T( trace(TRACE_DAEMON
, "daemon: reply sent"); )
274 /* --- @daemon_init@ --- *
276 * Arguments: @const char *cf@ = pointer to name of configuration file
277 * @int port@ = port to listen to, or %$-1$% for default
281 * Use: Starts `become' up in daemon mode.
284 void daemon_init(const char *cf
, int port
)
288 /* --- Remove my root privileges --- *
290 * Just in case there's anything dodgy in my configuration file, or the
291 * user wants me to start on a funny port.
296 /* --- Initialise bits of the program --- */
306 openlog(quis(), 0, LOG_DAEMON
);
307 syslog(LOG_NOTICE
, "starting up");
309 if (daemon__readConfig(cf
))
310 die("couldn't read configuration file");
312 /* --- Decide on a port to use --- *
314 * If I don't have a port yet (e.g., from the configuration file) then
315 * look it up in /etc/services under whatever name I was started as.
318 if (daemon__port
<= 0) {
319 struct servent
*se
= getservbyname(quis(), "udp");
321 die("no idea which port to use");
322 daemon__port
= ntohs(se
->s_port
);
325 /* --- Now set up a socket --- */
328 struct sockaddr_in sin
;
330 if ((s
= socket(PF_INET
, SOCK_DGRAM
, 0)) == -1)
331 die("couldn't create socket: %s", strerror(errno
));
332 sin
.sin_family
= AF_INET
;
333 sin
.sin_port
= htons(daemon__port
);
334 sin
.sin_addr
.s_addr
= htonl(INADDR_ANY
);
335 if (bind(s
, (struct sockaddr
*)&sin
, sizeof(sin
)))
336 die("couldn't bind socket to port: %s", strerror(errno
));
339 /* --- Fork off into the sunset --- */
346 /* --- Make a background process --- */
349 die("couldn't fork daemon: %s", strerror(errno
));
353 /* --- Disconnect from the terminal --- */
357 /* --- Write my process id to a file --- */
359 if ((fp
= fopen(file_PID
, "w")) != 0) {
360 fprintf(fp
, "%lu\n", (unsigned long)getpid());
363 T( trace(TRACE_DAEMON
, "daemon: forked to pid %li", (long)getpid()); )
367 /* --- Program in daemon death mode --- */
369 if (setjmp(daemon__dieBuf
)) {
371 if (daemon__signum
== SIGQUIT
&& tracing() & TRACE_RULE
) {
373 signal(SIGQUIT
, daemon__die
);
377 T( trace(TRACE_DAEMON
, "daemon: killed by signal %i",
379 syslog(LOG_NOTICE
, "killed by signal type %i", daemon__signum
);
385 /* --- Set signal handlers --- */
387 signal(SIGHUP
, daemon__restart
);
388 signal(SIGQUIT
, daemon__die
);
389 signal(SIGINT
, daemon__die
);
390 signal(SIGTERM
, daemon__die
);
391 signal(SIGSEGV
, daemon__die
);
392 signal(SIGFPE
, daemon__die
);
393 signal(SIGBUS
, daemon__die
);
396 /* --- Now wait for something exciting to happen --- *
398 * Actually, every so often (5 minutes, perhaps) I need to wake up and
399 * rescan the users to see whether they've changed. Time to play with
406 /* --- Find when I am, and thus when I need to be awoken again --- */
408 when
= time(0) + daemon__awakeEvery
;
414 /* --- Set up the file descriptor tables --- */
419 /* --- Now wait for something interesting --- */
421 T( trace(TRACE_DAEMON
, "daemon: waiting for requests"); )
422 i
= select(FD_SETSIZE
, &fds
, 0, 0, 0);
424 /* --- Now, see if I need to rescan the config --- */
426 if (daemon__rescan
|| time(0) - when
> 0) {
428 syslog(LOG_INFO
, "rescanning configuration file");
435 if (daemon__readConfig(cf
))
436 syslog(LOG_ERR
, "error reading configuration file");
437 when
= time(0) + daemon__awakeEvery
;
440 /* --- Read the data from the request --- */
448 /*----- That's all, folks -------------------------------------------------*/