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/*
23 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#include <door.h>
28#include <errno.h>
29#include <fcntl.h>
30#include <stdio.h>
31#include <stdlib.h>
32#include <synch.h>
33#include <time.h>
34#include <unistd.h>
35
36#include <sys/param.h>
37#include <sys/stat.h>
38#include <sys/types.h>
39
40#include "labeld.h"
41
42#ifndef	DEBUG
43#define	perror(e)
44#endif	/* !DEBUG */
45
46/*
47 *	This is cloned from _nsc_trydoorcall used by the nscd client.
48 *
49 * Routine that actually performs the door call.
50 * Note that we cache a file descriptor.  We do
51 * the following to prevent disasters:
52 *
53 * 1) Never use 0, 1 or 2; if we get this from the open
54 *    we dup it upwards.
55 *
56 * 2) Set the close on exec flags so descriptor remains available
57 *    to child processes.
58 *
59 * 3) Verify that the door is still the same one we had before
60 *    by using door_info on the client side.
61 *
62 *	Note that we never close the file descriptor if it isn't one
63 *	we allocated; we check this with door info.  The rather tricky
64 *	logic is designed to be fast in the normal case (fd is already
65 *	allocated and is ok) while handling the case where the application
66 *	closed it underneath us or where the nscd dies or re-execs itself
67 *	and we're a multi-threaded application.  Note that we cannot protect
68 *	the application if it closes the fd and it is multi-threaded.
69 *
70 *  int __call_labeld(label_door_op **dptr, int *ndata, int *adata);
71 *
72 *      *dptr	IN: points to arg buffer OUT: points to results buffer
73 *      *ndata	IN: overall size of buffer OUT: overall size of buffer
74 *      *adata	IN: size of call data OUT: size of return data
75 *
76 *  Note that *dptr may change if provided space as defined by *bufsize is
77 *  inadequate.  In this case the door call mmaps more space and places
78 *  the answer there and sets dptr to contain a pointer to the space, which
79 *  should be freed with munmap.
80 *
81 *  Returns 0 if the door call reached the server, -1 if contact was not made.
82 *
83 */
84
85
86static mutex_t	_door_lock = DEFAULTMUTEX;
87
88int
89__call_labeld(labeld_data_t **dptr, size_t *ndata, size_t *adata)
90{
91	static	int 		doorfd = -1;
92	static	door_info_t 	real_door;
93	struct stat		st;
94	door_info_t 		my_door;
95	door_arg_t		param;
96	char			door_name[MAXPATHLEN];
97	struct timespec		ts;
98	int			busy = 0;	/* number of busy loops */
99
100#ifdef	DEBUG
101	labeld_data_t		*callptr = *dptr;
102	int			buf_size = *ndata;
103	int			return_size = *adata;
104#endif	/* DEBUG */
105
106	/*
107	 * the first time in we try and open and validate the door.
108	 * the validations are that the door must have been
109	 * created with the label service door cookie and
110	 * that it has the same door ID.  If any of these
111	 * validations fail we refuse to use the door.
112	 */
113	ts.tv_sec = 0;		/* initialize nanosecond retry timer */
114	ts.tv_nsec = 100;
115	(void) mutex_lock(&_door_lock);
116
117try_again:
118	if (doorfd == -1) {
119		int	tbc[3];
120		int	i;
121
122		(void) snprintf(door_name, sizeof (door_name), "%s%s",
123		    DOOR_PATH, DOOR_NAME);
124		if ((doorfd = open64(door_name, O_RDONLY, 0)) < 0) {
125			(void) mutex_unlock(&_door_lock);
126			perror("server door open");
127			return (NOSERVER);
128		}
129
130		/*
131		 * dup up the file descriptor if we have 0 - 2
132		 * to avoid problems with shells stdin/out/err
133		 */
134		i = 0;
135		while (doorfd < 3) { /* we have a reserved fd */
136			tbc[i++] = doorfd;
137			if ((doorfd = dup(doorfd)) < 0) {
138				perror("couldn't dup");
139				while (i--)
140					(void) close(tbc[i]);
141				doorfd = -1;
142				(void) mutex_unlock(&_door_lock);
143				return (NOSERVER);
144			}
145		}
146		while (i--)
147			(void) close(tbc[i]);
148
149		/*
150		 * mark this door descriptor as close on exec
151		 */
152		(void) fcntl(doorfd, F_SETFD, FD_CLOEXEC);
153		if (door_info(doorfd, &real_door) < 0) {
154			/*
155			 * we should close doorfd because we just opened it
156			 */
157			perror("real door door_info");
158			(void) close(doorfd);
159			doorfd = -1;
160			(void) mutex_unlock(&_door_lock);
161			return (NOSERVER);
162		}
163		if (fstat(doorfd, &st) < 0) {
164			perror("real door fstat");
165			return (NOSERVER);
166		}
167#ifdef	DEBUG
168		(void) printf("\treal door %s\n", door_name);
169		(void) printf("\t\tuid = %d, gid = %d, mode = %o\n", st.st_uid,
170		    st.st_gid, st.st_mode);
171		(void) printf("\t\toutstanding requests = %d\n", st.st_nlink-1);
172		(void) printf("\t\t pid = %d\n", real_door.di_target);
173		(void) printf("\t\t procedure = %llx\n", real_door.di_proc);
174		(void) printf("\t\t cookie = %llx\n",  real_door.di_data);
175		(void) printf("\t\t attributes = %x\n",
176		    real_door.di_attributes);
177		if (real_door.di_attributes & DOOR_UNREF)
178			(void) printf("\t\t\t UNREF\n");
179		if (real_door.di_attributes & DOOR_PRIVATE)
180			(void) printf("\t\t\t PRIVATE\n");
181		if (real_door.di_attributes & DOOR_LOCAL)
182			(void) printf("\t\t\t LOCAL\n");
183		if (real_door.di_attributes & DOOR_REVOKED)
184			(void) printf("\t\t\t REVOKED\n");
185		if (real_door.di_attributes & DOOR_DESCRIPTOR)
186			(void) printf("\t\t\t DESCRIPTOR\n");
187		if (real_door.di_attributes & DOOR_RELEASE)
188			(void) printf("\t\t\t RELEASE\n");
189		if (real_door.di_attributes & DOOR_DELAY)
190			(void) printf("\t\t\t DELAY\n");
191		(void) printf("\t\t id = %llx\n", real_door.di_uniquifier);
192#endif	/* DEBUG */
193		if ((real_door.di_attributes & DOOR_REVOKED) ||
194		    (real_door.di_data != COOKIE)) {
195#ifdef	DEBUG
196			(void) printf("real door revoked\n");
197#endif	/* DEBUG */
198			(void) close(doorfd);
199			doorfd = -1;
200			(void) mutex_unlock(&_door_lock);
201			return (NOSERVER);
202		}
203	} else {
204		if ((door_info(doorfd, &my_door) < 0) ||
205		    (my_door.di_data != COOKIE) ||
206		    (my_door.di_uniquifier != real_door.di_uniquifier)) {
207			perror("my door door_info");
208			/*
209			 * don't close it - someone else has clobbered fd
210			 */
211			doorfd = -1;
212			goto try_again;
213		}
214		if (fstat(doorfd, &st) < 0) {
215			perror("my door fstat");
216			goto try_again;
217		}
218#ifdef	DEBUG
219		(void) sprintf(door_name, "%s%s", DOOR_PATH, DOOR_NAME);
220		(void) printf("\tmy door %s\n", door_name);
221		(void) printf("\t\tuid = %d, gid = %d, mode = %o\n", st.st_uid,
222		    st.st_gid, st.st_mode);
223		(void) printf("\t\toutstanding requests = %d\n", st.st_nlink-1);
224		(void) printf("\t\t pid = %d\n", my_door.di_target);
225		(void) printf("\t\t procedure = %llx\n", my_door.di_proc);
226		(void) printf("\t\t cookie = %llx\n",  my_door.di_data);
227		(void) printf("\t\t attributes = %x\n", my_door.di_attributes);
228		if (my_door.di_attributes & DOOR_UNREF)
229			(void) printf("\t\t\t UNREF\n");
230		if (my_door.di_attributes & DOOR_PRIVATE)
231			(void) printf("\t\t\t PRIVATE\n");
232		if (my_door.di_attributes & DOOR_LOCAL)
233			(void) printf("\t\t\t LOCAL\n");
234		if (my_door.di_attributes & DOOR_REVOKED)
235			(void) printf("\t\t\t REVOKED\n");
236		if (my_door.di_attributes & DOOR_DESCRIPTOR)
237			(void) printf("\t\t\t DESCRIPTOR\n");
238		if (my_door.di_attributes & DOOR_RELEASE)
239			(void) printf("\t\t\t RELEASE\n");
240		if (my_door.di_attributes & DOOR_DELAY)
241			(void) printf("\t\t\t DELAY\n");
242		(void) printf("\t\t id = %llx\n", my_door.di_uniquifier);
243#endif	/* DEBUG */
244		if (my_door.di_attributes & DOOR_REVOKED) {
245#ifdef	DEBUG
246			(void) printf("my door revoked\n");
247#endif	/* DEBUG */
248			(void) close(doorfd);	/* labeld exited .... */
249			doorfd = -1;	/* try and restart connection */
250			goto try_again;
251		}
252	}
253	(void) mutex_unlock(&_door_lock);
254
255	param.data_ptr = (char *)*dptr;
256	param.data_size = *adata;
257	param.desc_ptr = NULL;
258	param.desc_num = 0;
259	param.rbuf = (char *)*dptr;
260	param.rsize = *ndata;
261
262	if (door_call(doorfd, &param) < 0) {
263		if (errno == EAGAIN && busy++ < 10) {
264			/* adjust backoff */
265			if ((ts.tv_nsec *= 10) >= NANOSEC) {
266				ts.tv_sec++;
267				ts.tv_nsec = 100;
268			}
269			(void) nanosleep(&ts, NULL);
270#ifdef	DEBUG
271			(void) printf("door_call failed EAGAIN # %d\n", busy);
272#endif	/* DEBUG */
273			(void) mutex_lock(&_door_lock);
274			goto try_again;
275		}
276		perror("door call");
277		return (NOSERVER);
278	}
279
280	*adata = (int)param.data_size;
281	*ndata = (int)param.rsize;
282	/*LINTED*/
283	*dptr = (labeld_data_t *)param.data_ptr;
284
285	if (*adata == 0 || *dptr == NULL) {
286#ifdef	DEBUG
287		(void) printf("\tNo data returned, size = %lu, dptr = %p\n",
288		    (unsigned long)*adata, (void *)*dptr);
289#endif	/* DEBUG */
290		return (NOSERVER);
291	}
292#ifdef	DEBUG
293	(void) printf("call buf = %x, buf size  = %d, call size = %d\n",
294	    callptr, buf_size, return_size);
295	(void) printf("retn buf = %x, buf size  = %d, retn size = %d\n",
296	    *dptr, *ndata, *adata);
297	(void) printf("\treply status = %d\n", (*dptr)->param.aret.ret);
298#endif	/* DEBUG */
299	return ((*dptr)->param.aret.ret);
300
301}  /* __call_labeld */
302