2 Unix SMB/CIFS implementation.
5 Copyright (C) James Peach 2006
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #define DBGC_CLASS DBGC_DMAPI
27 #if defined(HAVE_LIBDM) || defined(HAVE_LIBJFSDM) || defined(HAVE_LIBXDSM)
28 #if defined(HAVE_XFS_DMAPI_H) || defined(HAVE_SYS_DMI_H) || defined(HAVE_SYS_JFSDMAPI_H) || defined(HAVE_SYS_DMAPI_H)
35 int dmapi_init_session(void) { return -1; }
36 uint32 dmapi_file_flags(const char * const path) { return 0; }
37 BOOL dmapi_have_session(void) { return False; }
41 #ifdef HAVE_XFS_DMAPI_H
42 #include <xfs/dmapi.h>
43 #elif defined(HAVE_SYS_DMI_H)
45 #elif defined(HAVE_SYS_JFSDMAPI_H)
46 #include <sys/jfsdmapi.h>
47 #elif defined(HAVE_SYS_DMAPI_H)
48 #include <sys/dmapi.h>
51 #define DMAPI_SESSION_NAME "samba"
52 #define DMAPI_TRACE 10
54 static dm_sessid_t dmapi_session = DM_NO_SESSION;
56 /* Initialise the DMAPI interface. Make sure that we only end up initialising
57 * once per process to avoid resource leaks across different DMAPI
60 static int init_dmapi_service(void)
67 if (mypid != lastpid) {
71 if (dm_init_service(&version) < 0) {
75 DEBUG(0, ("Initializing DMAPI: %s\n", version));
81 BOOL dmapi_have_session(void)
83 return dmapi_session != DM_NO_SESSION;
86 static dm_sessid_t *realloc_session_list(dm_sessid_t * sessions, int count)
88 dm_sessid_t *nsessions;
90 nsessions = TALLOC_REALLOC_ARRAY(NULL, sessions, dm_sessid_t, count);
91 if (nsessions == NULL) {
92 TALLOC_FREE(sessions);
99 /* Initialise DMAPI session. The session is persistant kernel state, so it
100 * might already exist, in which case we merely want to reconnect to it. This
101 * function should be called as root.
103 int dmapi_init_session(void)
105 char buf[DM_SESSION_INFO_LEN];
109 dm_sessid_t *sessions = NULL;
113 /* If we aren't root, something in the following will fail due to lack
114 * of privileges. Aborting seems a little extreme.
116 SMB_WARN(getuid() == 0, "dmapi_init_session must be called as root");
118 dmapi_session = DM_NO_SESSION;
119 if (init_dmapi_service() < 0) {
125 if ((sessions = realloc_session_list(sessions, nsessions)) == NULL) {
129 err = dm_getall_sessions(nsessions, sessions, &nsessions);
131 if (errno == E2BIG) {
136 DEBUGADD(DMAPI_TRACE,
137 ("failed to retrieve DMAPI sessions: %s\n",
139 TALLOC_FREE(sessions);
143 for (i = 0; i < nsessions; ++i) {
144 err = dm_query_session(sessions[i], sizeof(buf), buf, &buflen);
145 buf[sizeof(buf) - 1] = '\0';
146 if (err == 0 && strcmp(DMAPI_SESSION_NAME, buf) == 0) {
147 dmapi_session = sessions[i];
148 DEBUGADD(DMAPI_TRACE,
149 ("attached to existing DMAPI session "
150 "named '%s'\n", buf));
155 TALLOC_FREE(sessions);
157 /* No session already defined. */
158 if (dmapi_session == DM_NO_SESSION) {
159 err = dm_create_session(DM_NO_SESSION, DMAPI_SESSION_NAME,
162 DEBUGADD(DMAPI_TRACE,
163 ("failed to create new DMAPI session: %s\n",
165 dmapi_session = DM_NO_SESSION;
169 DEBUGADD(DMAPI_TRACE,
170 ("created new DMAPI session named '%s'\n",
171 DMAPI_SESSION_NAME));
174 /* Note that we never end the DMAPI session. This enables child
175 * processes to continue to use the session after we exit. It also lets
176 * you run a second Samba server on different ports without any
183 /* Reattach to an existing dmapi session. Called from service processes that
184 * might not be running as root.
186 static int reattach_dmapi_session(void)
188 char buf[DM_SESSION_INFO_LEN];
191 if (dmapi_session != DM_NO_SESSION ) {
194 /* NOTE: On Linux, this call opens /dev/dmapi, costing us a
195 * file descriptor. Ideally, we would close this when we fork.
197 if (init_dmapi_service() < 0) {
198 dmapi_session = DM_NO_SESSION;
203 if (dm_query_session(dmapi_session, sizeof(buf),
205 /* Session is stale. Disable DMAPI. */
206 dmapi_session = DM_NO_SESSION;
211 set_effective_capability(DMAPI_ACCESS_CAPABILITY);
213 DEBUG(DMAPI_TRACE, ("reattached DMAPI session\n"));
220 uint32 dmapi_file_flags(const char * const path)
222 static int attached = 0;
225 dm_eventset_t events = {0};
229 size_t dm_handle_len;
233 /* If a DMAPI session has been initialised, then we need to make sure
234 * we are attached to it and have the correct privileges. This is
235 * necessary to be able to do DMAPI operations across a fork(2). If
236 * it fails, there is no liklihood of that failure being transient.
238 * Note that this use of the static attached flag relies on the fact
239 * that dmapi_file_flags() is never called prior to forking the
240 * per-client server process.
242 if (dmapi_have_session() && !attached) {
244 if (reattach_dmapi_session() < 0) {
249 err = dm_path_to_handle(CONST_DISCARD(char *, path),
250 &dm_handle, &dm_handle_len);
252 DEBUG(DMAPI_TRACE, ("dm_path_to_handle(%s): %s\n",
253 path, strerror(errno)));
255 if (errno != EPERM) {
259 /* Linux capabilities are broken in that changing our
260 * user ID will clobber out effective capabilities irrespective
261 * of whether we have set PR_SET_KEEPCAPS. Fortunately, the
262 * capabilities are not removed from our permitted set, so we
263 * can re-acquire them if necessary.
266 set_effective_capability(DMAPI_ACCESS_CAPABILITY);
268 err = dm_path_to_handle(CONST_DISCARD(char *, path),
269 &dm_handle, &dm_handle_len);
272 ("retrying dm_path_to_handle(%s): %s\n",
273 path, strerror(errno)));
278 err = dm_get_eventlist(dmapi_session, dm_handle, dm_handle_len,
279 DM_NO_TOKEN, DM_EVENT_MAX, &events, &nevents);
281 DEBUG(DMAPI_TRACE, ("dm_get_eventlist(%s): %s\n",
282 path, strerror(errno)));
283 dm_handle_free(dm_handle, dm_handle_len);
287 /* We figure that the only reason a DMAPI application would be
288 * interested in trapping read events is that part of the file is
291 DEBUG(DMAPI_TRACE, ("DMAPI event list for %s is %#llx\n",
293 if (DMEV_ISSET(DM_EVENT_READ, events)) {
294 flags = FILE_ATTRIBUTE_OFFLINE;
297 dm_handle_free(dm_handle, dm_handle_len);
299 if (flags & FILE_ATTRIBUTE_OFFLINE) {
300 DEBUG(DMAPI_TRACE, ("%s is OFFLINE\n", path));
306 #endif /* USE_DMAPI */