source: vendor/3.5.2/source3/modules/vfs_fileid.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 6.8 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
24static int vfs_fileid_debug_level = DBGC_VFS;
25
26#undef DBGC_CLASS
27#define DBGC_CLASS vfs_fileid_debug_level
28
29struct fileid_mount_entry {
30 SMB_DEV_T device;
31 const char *mnt_fsname;
32 fsid_t fsid;
33 uint64_t devid;
34};
35
36struct fileid_handle_data {
37 uint64_t (*device_mapping_fn)(struct fileid_handle_data *data,
38 SMB_DEV_T dev);
39 unsigned num_mount_entries;
40 struct fileid_mount_entry *mount_entries;
41};
42
43/* load all the mount entries from the mtab */
44static void fileid_load_mount_entries(struct fileid_handle_data *data)
45{
46 FILE *f;
47 struct mntent *m;
48
49 data->num_mount_entries = 0;
50 TALLOC_FREE(data->mount_entries);
51
52 f = setmntent("/etc/mtab", "r");
53 if (!f) return;
54
55 while ((m = getmntent(f))) {
56 struct stat st;
57 struct statfs sfs;
58 struct fileid_mount_entry *cur;
59
60 if (stat(m->mnt_dir, &st) != 0) continue;
61 if (statfs(m->mnt_dir, &sfs) != 0) continue;
62
63 if (strncmp(m->mnt_fsname, "/dev/", 5) == 0) {
64 m->mnt_fsname += 5;
65 }
66
67 data->mount_entries = TALLOC_REALLOC_ARRAY(data,
68 data->mount_entries,
69 struct fileid_mount_entry,
70 data->num_mount_entries+1);
71 if (data->mount_entries == NULL) {
72 goto nomem;
73 }
74
75 cur = &data->mount_entries[data->num_mount_entries];
76 cur->device = st.st_dev;
77 cur->mnt_fsname = talloc_strdup(data->mount_entries,
78 m->mnt_fsname);
79 if (!cur->mnt_fsname) goto nomem;
80 cur->fsid = sfs.f_fsid;
81 cur->devid = (uint64_t)-1;
82
83 data->num_mount_entries++;
84 }
85 endmntent(f);
86 return;
87
88nomem:
89 if (f) endmntent(f);
90
91 data->num_mount_entries = 0;
92 TALLOC_FREE(data->mount_entries);
93
94 return;
95}
96
97/* find a mount entry given a dev_t */
98static struct fileid_mount_entry *fileid_find_mount_entry(struct fileid_handle_data *data,
99 SMB_DEV_T dev)
100{
101 int i;
102
103 if (data->num_mount_entries == 0) {
104 fileid_load_mount_entries(data);
105 }
106 for (i=0;i<data->num_mount_entries;i++) {
107 if (data->mount_entries[i].device == dev) {
108 return &data->mount_entries[i];
109 }
110 }
111 /* 2nd pass after reloading */
112 fileid_load_mount_entries(data);
113 for (i=0;i<data->num_mount_entries;i++) {
114 if (data->mount_entries[i].device == dev) {
115 return &data->mount_entries[i];
116 }
117 }
118 return NULL;
119}
120
121
122/* a 64 bit hash, based on the one in tdb */
123static uint64_t fileid_uint64_hash(const uint8_t *s, size_t len)
124{
125 uint64_t value; /* Used to compute the hash value. */
126 uint32_t i; /* Used to cycle through random values. */
127
128 /* Set the initial value from the key size. */
129 for (value = 0x238F13AFLL * len, i=0; i < len; i++)
130 value = (value + (s[i] << (i*5 % 24)));
131
132 return (1103515243LL * value + 12345LL);
133}
134
135/* a device mapping using a fsname */
136static uint64_t fileid_device_mapping_fsname(struct fileid_handle_data *data,
137 SMB_DEV_T dev)
138{
139 struct fileid_mount_entry *m;
140
141 m = fileid_find_mount_entry(data, dev);
142 if (!m) return dev;
143
144 if (m->devid == (uint64_t)-1) {
145 m->devid = fileid_uint64_hash((uint8_t *)m->mnt_fsname,
146 strlen(m->mnt_fsname));
147 }
148
149 return m->devid;
150}
151
152/* device mapping functions using a fsid */
153static uint64_t fileid_device_mapping_fsid(struct fileid_handle_data *data,
154 SMB_DEV_T dev)
155{
156 struct fileid_mount_entry *m;
157
158 m = fileid_find_mount_entry(data, dev);
159 if (!m) return dev;
160
161 if (m->devid == (uint64_t)-1) {
162 if (sizeof(fsid_t) > sizeof(uint64_t)) {
163 m->devid = fileid_uint64_hash((uint8_t *)&m->fsid,
164 sizeof(m->fsid));
165 } else {
166 union {
167 uint64_t ret;
168 fsid_t fsid;
169 } u;
170 ZERO_STRUCT(u);
171 u.fsid = m->fsid;
172 m->devid = u.ret;
173 }
174 }
175
176 return m->devid;
177}
178
179static int fileid_connect(struct vfs_handle_struct *handle,
180 const char *service, const char *user)
181{
182 struct fileid_handle_data *data;
183 const char *algorithm;
184 int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
185
186 if (ret < 0) {
187 return ret;
188 }
189
190 data = talloc_zero(handle->conn, struct fileid_handle_data);
191 if (!data) {
192 SMB_VFS_NEXT_DISCONNECT(handle);
193 DEBUG(0, ("talloc_zero() failed\n"));
194 return -1;
195 }
196
197 /*
198 * "fileid:mapping" is only here as fallback for old setups
199 * "fileid:algorithm" is the option new setups should use
200 */
201 algorithm = lp_parm_const_string(SNUM(handle->conn),
202 "fileid", "mapping",
203 "fsname");
204 algorithm = lp_parm_const_string(SNUM(handle->conn),
205 "fileid", "algorithm",
206 algorithm);
207 if (strcmp("fsname", algorithm) == 0) {
208 data->device_mapping_fn = fileid_device_mapping_fsname;
209 } else if (strcmp("fsid", algorithm) == 0) {
210 data->device_mapping_fn = fileid_device_mapping_fsid;
211 } else {
212 SMB_VFS_NEXT_DISCONNECT(handle);
213 DEBUG(0,("fileid_connect(): unknown algorithm[%s]\n", algorithm));
214 return -1;
215 }
216
217 SMB_VFS_HANDLE_SET_DATA(handle, data, NULL,
218 struct fileid_handle_data,
219 return -1);
220
221 DEBUG(10, ("fileid_connect(): connect to service[%s] with algorithm[%s]\n",
222 service, algorithm));
223
224 return 0;
225}
226
227static void fileid_disconnect(struct vfs_handle_struct *handle)
228{
229 DEBUG(10,("fileid_disconnect() connect to service[%s].\n",
230 lp_servicename(SNUM(handle->conn))));
231
232 SMB_VFS_NEXT_DISCONNECT(handle);
233}
234
235static struct file_id fileid_file_id_create(struct vfs_handle_struct *handle,
236 const SMB_STRUCT_STAT *sbuf)
237{
238 struct fileid_handle_data *data;
239 struct file_id id;
240
241 ZERO_STRUCT(id);
242
243 SMB_VFS_HANDLE_GET_DATA(handle, data,
244 struct fileid_handle_data,
245 return id);
246
247 id.devid = data->device_mapping_fn(data, sbuf->st_ex_dev);
248 id.inode = sbuf->st_ex_ino;
249
250 return id;
251}
252
253static struct vfs_fn_pointers vfs_fileid_fns = {
254 .connect_fn = fileid_connect,
255 .disconnect = fileid_disconnect,
256 .file_id_create = fileid_file_id_create
257};
258
259NTSTATUS vfs_fileid_init(void);
260NTSTATUS vfs_fileid_init(void)
261{
262 NTSTATUS ret;
263
264 ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "fileid",
265 &vfs_fileid_fns);
266 if (!NT_STATUS_IS_OK(ret)) {
267 return ret;
268 }
269
270 vfs_fileid_debug_level = debug_add_class("fileid");
271 if (vfs_fileid_debug_level == -1) {
272 vfs_fileid_debug_level = DBGC_VFS;
273 DEBUG(0, ("vfs_fileid: Couldn't register custom debugging class!\n"));
274 } else {
275 DEBUG(10, ("vfs_fileid: Debug class number of 'fileid': %d\n", vfs_fileid_debug_level));
276 }
277
278 return ret;
279}
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