xref: /illumos-gate/usr/src/cmd/fs.d/reparsed/reparsed.c (revision 698f4ab6008be205f4362675967638572eef4f21)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * Copyright 2019 Joyent, Inc.
28  */
29 
30 /*
31  * Reparsed daemon
32  */
33 
34 #include <stdio.h>
35 #include <stdio_ext.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38 #include <signal.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42 #include <memory.h>
43 #include <alloca.h>
44 #include <ucontext.h>
45 #include <errno.h>
46 #include <syslog.h>
47 #include <string.h>
48 #include <strings.h>
49 #include <door.h>
50 #include <wait.h>
51 #include <libintl.h>
52 #include <locale.h>
53 #include <sys/param.h>
54 #include <sys/systeminfo.h>
55 #include <sys/thread.h>
56 #include <rpc/xdr.h>
57 #include <priv.h>
58 #include <sys/fs_reparse.h>
59 #include <priv_utils.h>
60 #include <rpcsvc/daemon_utils.h>
61 
62 #define	REPARSED_CMD_OPTS	"v"
63 #define	DOOR_RESULT_BUFSZ	(MAXPATHLEN + sizeof (reparsed_door_res_t))
64 #define	SAFETY_BUFFER		8*1024
65 
66 static char *MyName;
67 static int verbose = 0;
68 
69 static int start_reparsed_svcs();
70 static void daemonize(void);
71 static void reparsed_door_call_error(int error, int buflen);
72 static void reparsed_doorfunc(void *cookie, char *argp, size_t arg_size,
73 			door_desc_t *dp, uint_t n_desc);
74 
75 static void
76 usage()
77 {
78 	syslog(LOG_ERR, "Usage: %s", MyName);
79 	syslog(LOG_ERR, "\t[-v]\t\tverbose error messages)");
80 	exit(1);
81 }
82 
83 static void
84 warn_hup(int i)
85 {
86 	syslog(LOG_ERR, "SIGHUP received: ignored");
87 	(void) signal(SIGHUP, warn_hup);
88 }
89 
90 /*
91  * Processing for daemonization
92  */
93 static void
94 daemonize(void)
95 {
96 	switch (fork()) {
97 	case -1:
98 		syslog(LOG_ERR, "reparsed: can't fork - errno %d", errno);
99 		exit(2);
100 		/* NOTREACHED */
101 	case 0:		/* child */
102 		break;
103 
104 	default:	/* parent */
105 		_exit(0);
106 	}
107 	(void) chdir("/");
108 
109 	/*
110 	 * Close stdin, stdout, and stderr.
111 	 * Open again to redirect input+output
112 	 */
113 	(void) close(0);
114 	(void) close(1);
115 	(void) close(2);
116 	(void) open("/dev/null", O_RDONLY);
117 	(void) open("/dev/null", O_WRONLY);
118 	(void) dup(1);
119 	(void) setsid();
120 }
121 
122 int
123 main(int argc, char *argv[])
124 {
125 	pid_t pid;
126 	int c, error;
127 	struct rlimit rlset;
128 	char *defval;
129 
130 	/*
131 	 * There is no check for non-global zone and Trusted Extensions.
132 	 * Reparsed works in both of these environments as long as the
133 	 * services that use reparsed are supported.
134 	 */
135 
136 	MyName = argv[0];
137 	if (geteuid() != 0) {
138 		syslog(LOG_ERR, "%s must be run as root", MyName);
139 		exit(1);
140 	}
141 
142 	while ((c = getopt(argc, argv, REPARSED_CMD_OPTS)) != EOF) {
143 		switch (c) {
144 		case 'v':
145 			verbose++;
146 			break;
147 		default:
148 			usage();
149 		}
150 	}
151 
152 	daemonize();
153 	openlog(MyName, LOG_PID | LOG_NDELAY, LOG_DAEMON);
154 
155 	(void) _create_daemon_lock(REPARSED, DAEMON_UID, DAEMON_GID);
156 	(void) enable_extended_FILE_stdio(-1, -1);
157 	switch (_enter_daemon_lock(REPARSED)) {
158 	case 0:
159 		break;
160 	case -1:
161 		syslog(LOG_ERR, "Error locking for %s", REPARSED);
162 		exit(2);
163 	default:
164 		/* daemon was already running */
165 		exit(0);
166 	}
167 
168 	(void) signal(SIGHUP, warn_hup);
169 
170 	/*
171 	 * Make the process a privilege aware daemon.
172 	 * Only "basic" privileges are required.
173 	 *
174 	 */
175 	if (__init_daemon_priv(PU_RESETGROUPS|PU_CLEARLIMITSET, 0, 0,
176 	    (char *)NULL) == -1) {
177 		syslog(LOG_ERR, "should be run with sufficient privileges");
178 		exit(3);
179 	}
180 
181 	/*
182 	 * Clear basic privileges not required by reparsed.
183 	 */
184 	__fini_daemon_priv(PRIV_PROC_FORK, PRIV_PROC_EXEC, PRIV_PROC_SESSION,
185 	    PRIV_FILE_LINK_ANY, PRIV_PROC_INFO, (char *)NULL);
186 
187 	return (start_reparsed_svcs());
188 }
189 
190 __NORETURN static void
191 reparsed_door_call_error(int error, int buflen)
192 {
193 	reparsed_door_res_t rpd_res;
194 
195 	memset(&rpd_res, 0, sizeof (reparsed_door_res_t));
196 	rpd_res.res_status = error;
197 	rpd_res.res_len = buflen;
198 	(void) door_return((char *)&rpd_res,
199 	    sizeof (reparsed_door_res_t), NULL, 0);
200 
201 	(void) door_return(NULL, 0, NULL, 0);
202 	abort();
203 }
204 
205 /*
206  *  reparsed_doorfunc
207  *
208  *  argp:  "service_type:service_data" string
209  *  dp & n_desc: not used.
210  */
211 static void
212 reparsed_doorfunc(void *cookie, char *argp, size_t arg_size,
213     door_desc_t *dp, uint_t n_desc)
214 {
215 	int err;
216 	size_t bufsz;
217 	char *svc_type, *svc_data;
218 	char *cp, *buf, *sbuf, res_buf[DOOR_RESULT_BUFSZ];
219 	reparsed_door_res_t *resp;
220 
221 	if ((argp == NULL) || (arg_size == 0)) {
222 		reparsed_door_call_error(EINVAL, 0);
223 		/* NOTREACHED */
224 	}
225 
226 	if (verbose)
227 		syslog(LOG_NOTICE, "reparsed_door: [%s, %d]", argp, arg_size);
228 
229 	if ((svc_type = strdup(argp)) == NULL) {
230 		reparsed_door_call_error(ENOMEM, 0);
231 		/* NOTREACHED */
232 	}
233 
234 	/*
235 	 * Door argument string comes in "service_type:service_data" format.
236 	 * Need to break it into separate "service_type" and "service_data"
237 	 * string before passing them to reparse_deref() to process them.
238 	 */
239 	if ((cp = strchr(svc_type, ':')) == NULL) {
240 		free(svc_type);
241 		reparsed_door_call_error(EINVAL, 0);
242 		/* NOTREACHED */
243 	}
244 	*cp++ = '\0';
245 	svc_data = cp;
246 
247 	/*
248 	 * Setup buffer for reparse_deref(). 'bufsz' is the actual
249 	 * buffer size to hold the result returned by reparse_deref().
250 	 */
251 	resp = (reparsed_door_res_t *)res_buf;
252 	buf = resp->res_data;
253 	bufsz = sizeof (res_buf) - sizeof (reparsed_door_res_t);
254 
255 	/*
256 	 * reparse_deref() calls the service type plugin library to process
257 	 * the service data. The plugin library function should understand
258 	 * the context of the service data and should be the one to XDR the
259 	 * results before returning it to the caller.
260 	 */
261 	err = reparse_deref(svc_type, svc_data, buf, &bufsz);
262 
263 	if (verbose)
264 		syslog(LOG_NOTICE,
265 		    "reparsed_deref(svc_type: %s, data: %s, size: %d) -> %d",
266 		    svc_type, svc_data, bufsz, err);
267 
268 	switch (err) {
269 	case 0:
270 		break;
271 
272 	case EOVERFLOW:
273 		/*
274 		 * bufsz was returned with size needed by reparse_deref().
275 		 *
276 		 * We cannot use malloc() here because door_return() never
277 		 * returns, and memory allocated by malloc() would get leaked.
278 		 */
279 		sbuf = alloca(bufsz + sizeof (reparsed_door_res_t));
280 		if (sbuf == NULL || stack_inbounds(buf) == 0 ||
281 		    stack_inbounds(buf + sizeof (reparsed_door_res_t) +
282 		    SAFETY_BUFFER - 1) == 0) {
283 			free(svc_type);
284 			reparsed_door_call_error(ENOMEM, 0);
285 			/* NOTREACHED */
286 		}
287 
288 		resp = (reparsed_door_res_t *)sbuf;
289 		if ((err = reparse_deref(svc_type, svc_data, resp->res_data,
290 		    &bufsz)) == 0)
291 			break;
292 
293 		/* fall through */
294 
295 	default:
296 		free(svc_type);
297 		reparsed_door_call_error(err, 0);
298 		/* NOTREACHED */
299 	}
300 
301 	free(svc_type);
302 
303 	if (verbose)
304 		syslog(LOG_NOTICE, "reparsed_door_return <buf=%s> size=%d",
305 		    buf, bufsz);
306 
307 	resp->res_status = 0;
308 	resp->res_len = bufsz;
309 	(void) door_return((char *)resp, bufsz + sizeof (reparsed_door_res_t),
310 	    NULL, 0);
311 
312 	(void) door_return(NULL, 0, NULL, 0);
313 	/* NOTREACHED */
314 }
315 
316 static int
317 start_reparsed_svcs()
318 {
319 	int doorfd;
320 	int dfd;
321 
322 	if ((doorfd = door_create(reparsed_doorfunc, NULL,
323 	    DOOR_REFUSE_DESC|DOOR_NO_CANCEL)) == -1) {
324 		syslog(LOG_ERR, "Unable to create door");
325 		return (1);
326 	}
327 
328 	/*
329 	 * Create a file system path for the door
330 	 */
331 	if ((dfd = open(REPARSED_DOOR, O_RDWR|O_CREAT|O_TRUNC,
332 	    S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)) == -1) {
333 		syslog(LOG_ERR, "unable to open %s", REPARSED_DOOR);
334 		(void) close(doorfd);
335 		return (1);
336 	}
337 
338 	/*
339 	 * Clean up any stale associations
340 	 */
341 	(void) fdetach(REPARSED_DOOR);
342 
343 	/*
344 	 * Register in the kernel namespace for door_ki_open().
345 	 */
346 	if (fattach(doorfd, REPARSED_DOOR) == -1) {
347 		syslog(LOG_ERR, "Unable to fattach door %s", REPARSED_DOOR);
348 		(void) close(doorfd);
349 		(void) close(dfd);
350 		return (1);
351 	}
352 	(void) close(dfd);
353 
354 	/*
355 	 * Wait for incoming calls
356 	 */
357 	while (1)
358 		(void) pause();
359 }
360