source: vendor/3.6.9/source3/modules/vfs_fileid.c

Last change on this file was 740, checked in by Silvan Scherrer, 13 years ago

Samba Server: update vendor to 3.6.0
File size: 7.1 KB
Line 
1/*
2 * VFS module to alter the algorithm to calculate
3 * the struct file_id used as key for the share mode
4 * and byte range locking db's.
5 *
6 * Copyright (C) 2007, Stefan Metzmacher
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, see <http://www.gnu.org/licenses/>.
20 */
21
22#include "includes.h"
23#include "smbd/smbd.h"
24#include "system/filesys.h"
25
26static int vfs_fileid_debug_level = DBGC_VFS;
27
28#undef DBGC_CLASS
29#define DBGC_CLASS vfs_fileid_debug_level
30
31struct fileid_mount_entry {
32 SMB_DEV_T device;
33 const char *mnt_fsname;
34 fsid_t fsid;
35 uint64_t devid;
36};
37
38struct fileid_handle_data {
39 uint64_t (*device_mapping_fn)(struct fileid_handle_data *data,
40 SMB_DEV_T dev);
41 unsigned num_mount_entries;
42 struct fileid_mount_entry *mount_entries;
43};
44
45/* load all the mount entries from the mtab */
46static void fileid_load_mount_entries(struct fileid_handle_data *data)
47{
48 FILE *f;
49 struct mntent *m;
50
51 data->num_mount_entries = 0;
52 TALLOC_FREE(data->mount_entries);
53
54 f = setmntent("/etc/mtab", "r");
55 if (!f) return;
56
57 while ((m = getmntent(f))) {
58 struct stat st;
59 struct statfs sfs;
60 struct fileid_mount_entry *cur;
61
62 if (stat(m->mnt_dir, &st) != 0) continue;
63 if (statfs(m->mnt_dir, &sfs) != 0) continue;
64
65 if (strncmp(m->mnt_fsname, "/dev/", 5) == 0) {
66 m->mnt_fsname += 5;
67 }
68
69 data->mount_entries = TALLOC_REALLOC_ARRAY(data,
70 data->mount_entries,
71 struct fileid_mount_entry,
72 data->num_mount_entries+1);
73 if (data->mount_entries == NULL) {
74 goto nomem;
75 }
76
77 cur = &data->mount_entries[data->num_mount_entries];
78 cur->device = st.st_dev;
79 cur->mnt_fsname = talloc_strdup(data->mount_entries,
80 m->mnt_fsname);
81 if (!cur->mnt_fsname) goto nomem;
82 cur->fsid = sfs.f_fsid;
83 cur->devid = (uint64_t)-1;
84
85 data->num_mount_entries++;
86 }
87 endmntent(f);
88 return;
89
90nomem:
91 if (f) endmntent(f);
92
93 data->num_mount_entries = 0;
94 TALLOC_FREE(data->mount_entries);
95
96 return;
97}
98
99/* find a mount entry given a dev_t */
100static struct fileid_mount_entry *fileid_find_mount_entry(struct fileid_handle_data *data,
101 SMB_DEV_T dev)
102{
103 int i;
104
105 if (data->num_mount_entries == 0) {
106 fileid_load_mount_entries(data);
107 }
108 for (i=0;i<data->num_mount_entries;i++) {
109 if (data->mount_entries[i].device == dev) {
110 return &data->mount_entries[i];
111 }
112 }
113 /* 2nd pass after reloading */
114 fileid_load_mount_entries(data);
115 for (i=0;i<data->num_mount_entries;i++) {
116 if (data->mount_entries[i].device == dev) {
117 return &data->mount_entries[i];
118 }
119 }
120 return NULL;
121}
122
123
124/* a 64 bit hash, based on the one in tdb */
125static uint64_t fileid_uint64_hash(const uint8_t *s, size_t len)
126{
127 uint64_t value; /* Used to compute the hash value. */
128 uint32_t i; /* Used to cycle through random values. */
129
130 /* Set the initial value from the key size. */
131 for (value = 0x238F13AFLL * len, i=0; i < len; i++)
132 value = (value + (s[i] << (i*5 % 24)));
133
134 return (1103515243LL * value + 12345LL);
135}
136
137/* a device mapping using a fsname */
138static uint64_t fileid_device_mapping_fsname(struct fileid_handle_data *data,
139 SMB_DEV_T dev)
140{
141 struct fileid_mount_entry *m;
142
143 m = fileid_find_mount_entry(data, dev);
144 if (!m) return dev;
145
146 if (m->devid == (uint64_t)-1) {
147 m->devid = fileid_uint64_hash((uint8_t *)m->mnt_fsname,
148 strlen(m->mnt_fsname));
149 }
150
151 return m->devid;
152}
153
154/* device mapping functions using a fsid */
155static uint64_t fileid_device_mapping_fsid(struct fileid_handle_data *data,
156 SMB_DEV_T dev)
157{
158 struct fileid_mount_entry *m;
159
160 m = fileid_find_mount_entry(data, dev);
161 if (!m) return dev;
162
163 if (m->devid == (uint64_t)-1) {
164 if (sizeof(fsid_t) > sizeof(uint64_t)) {
165 m->devid = fileid_uint64_hash((uint8_t *)&m->fsid,
166 sizeof(m->fsid));
167 } else {
168 union {
169 uint64_t ret;
170 fsid_t fsid;
171 } u;
172 ZERO_STRUCT(u);
173 u.fsid = m->fsid;
174 m->devid = u.ret;
175 }
176 }
177
178 return m->devid;
179}
180
181static int fileid_connect(struct vfs_handle_struct *handle,
182 const char *service, const char *user)
183{
184 struct fileid_handle_data *data;
185 const char *algorithm;
186 int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
187
188 if (ret < 0) {
189 return ret;
190 }
191
192 data = talloc_zero(handle->conn, struct fileid_handle_data);
193 if (!data) {
194 SMB_VFS_NEXT_DISCONNECT(handle);
195 DEBUG(0, ("talloc_zero() failed\n"));
196 return -1;
197 }
198
199 /*
200 * "fileid:mapping" is only here as fallback for old setups
201 * "fileid:algorithm" is the option new setups should use
202 */
203 algorithm = lp_parm_const_string(SNUM(handle->conn),
204 "fileid", "mapping",
205 "fsname");
206 algorithm = lp_parm_const_string(SNUM(handle->conn),
207 "fileid", "algorithm",
208 algorithm);
209 if (strcmp("fsname", algorithm) == 0) {
210 data->device_mapping_fn = fileid_device_mapping_fsname;
211 } else if (strcmp("fsid", algorithm) == 0) {
212 data->device_mapping_fn = fileid_device_mapping_fsid;
213 } else {
214 SMB_VFS_NEXT_DISCONNECT(handle);
215 DEBUG(0,("fileid_connect(): unknown algorithm[%s]\n", algorithm));
216 return -1;
217 }
218
219 SMB_VFS_HANDLE_SET_DATA(handle, data, NULL,
220 struct fileid_handle_data,
221 return -1);
222
223 DEBUG(10, ("fileid_connect(): connect to service[%s] with algorithm[%s]\n",
224 service, algorithm));
225
226 return 0;
227}
228
229static void fileid_disconnect(struct vfs_handle_struct *handle)
230{
231 DEBUG(10,("fileid_disconnect() connect to service[%s].\n",
232 lp_servicename(SNUM(handle->conn))));
233
234 SMB_VFS_NEXT_DISCONNECT(handle);
235}
236
237static struct file_id fileid_file_id_create(struct vfs_handle_struct *handle,
238 const SMB_STRUCT_STAT *sbuf)
239{
240 struct fileid_handle_data *data;
241 struct file_id id;
242
243 ZERO_STRUCT(id);
244
245 SMB_VFS_HANDLE_GET_DATA(handle, data,
246 struct fileid_handle_data,
247 return id);
248
249 id.devid = data->device_mapping_fn(data, sbuf->st_ex_dev);
250 id.inode = sbuf->st_ex_ino;
251
252 return id;
253}
254
255static struct vfs_fn_pointers vfs_fileid_fns = {
256 .connect_fn = fileid_connect,
257 .disconnect = fileid_disconnect,
258 .file_id_create = fileid_file_id_create
259};
260
261NTSTATUS vfs_fileid_init(void);
262NTSTATUS vfs_fileid_init(void)
263{
264 NTSTATUS ret;
265
266 ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "fileid",
267 &vfs_fileid_fns);
268 if (!NT_STATUS_IS_OK(ret)) {
269 return ret;
270 }
271
272 vfs_fileid_debug_level = debug_add_class("fileid");
273 if (vfs_fileid_debug_level == -1) {
274 vfs_fileid_debug_level = DBGC_VFS;
275 DEBUG(0, ("vfs_fileid: Couldn't register custom debugging class!\n"));
276 } else {
277 DEBUG(10, ("vfs_fileid: Debug class number of 'fileid': %d\n", vfs_fileid_debug_level));
278 }
279
280 return ret;
281}
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