2 Bacula® - The Network Backup Solution
4 Copyright (C) 2009-2010 Free Software Foundation Europe e.V.
6 The main author of Bacula is Kern Sibbald, with contributions from
7 many others, a complete list can be found in the file AUTHORS.
8 This program is Free Software; you can redistribute it and/or
9 modify it under the terms of version three of the GNU Affero General Public
10 License as published by the Free Software Foundation and included
13 This program is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU Affero General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
23 Bacula® is a registered trademark of Kern Sibbald.
24 The licensor of Bacula is the Free Software Foundation Europe
25 (FSFE), Fiduciary Program, Sumatrastrasse 25, 8006 Zürich,
26 Switzerland, email:ftf@fsfeurope.org.
30 * This code implements a cache with the current mounted filesystems for which
31 * its uses the mostly in kernel mount information and export the different OS
32 * specific interfaces using a generic interface. We use a hashed cache which is
33 * accessed using a hash on the device id and we keep the previous cache hit as
34 * most of the time we get called quite a lot with most of the time the same
35 * device so keeping the previous cache hit we have a very optimized code path.
37 * This interface is implemented for the following OS-es:
47 * Currently we only use this code for Linux and OSF1 based fstype determination.
48 * For the other OS-es we can use the fstype present in stat structure on those OS-es.
50 * This code replaces the big switch we used before based on SUPER_MAGIC present in
51 * the statfs(2) structure but which need extra code for each new filesystem added to
52 * the OS and for Linux that tends to be often as it has quite some different filesystems.
53 * This new implementation should eliminate this as we use the Linux /proc/mounts in kernel
54 * data which automatically adds any new filesystem when added to the kernel.
58 * Marco van Wieringen, August 2009
62 #include "mntent_cache.h"
67 #include <sys/types.h>
70 #if defined(HAVE_GETMNTENT)
71 #if defined(HAVE_LINUX_OS) || defined(HAVE_HPUX_OS)
73 #elif defined(HAVE_SUN_OS)
74 #include <sys/mnttab.h>
75 #endif /* HAVE_GETMNTENT */
76 #elif defined(HAVE_GETMNTINFO)
77 #if defined(HAVE_DARWIN_OS)
78 #include <sys/param.h>
79 #include <sys/ucred.h>
80 #include <sys/mount.h>
82 #include <sys/types.h>
83 #include <sys/statvfs.h>
85 #elif defined(HAVE_AIX_OS)
88 #elif defined(HAVE_OSF1_OS)
89 #include <sys/mount.h>
92 static char cache_initialized = 0;
95 * Protected data by mutex lock.
97 static pthread_mutex_t mntent_cache_lock = PTHREAD_MUTEX_INITIALIZER;
98 static mntent_cache_entry_t *mntent_cache_entry_hashtable[NR_MNTENT_CACHE_ENTRIES];
99 static mntent_cache_entry_t *previous_cache_hit = NULL;
102 * Simple hash function.
104 static uint32_t mntent_hash_function(uint32_t dev)
106 return (dev % NR_MNTENT_CACHE_ENTRIES);
110 * Add a new entry to the cache.
111 * This function should be called with a write lock on the mntent_cache.
113 static void add_mntent_mapping(uint32_t dev, const char *special, const char *mountpoint,
114 const char *fstype, const char *mntopts)
117 mntent_cache_entry_t *mce;
120 * Select the correct hash bucket.
122 hash = mntent_hash_function(dev);
125 * See if this is the first being put into the hash bucket.
127 if (mntent_cache_entry_hashtable[hash] == (mntent_cache_entry_t *)NULL) {
128 mce = (mntent_cache_entry_t *)malloc(sizeof(mntent_cache_entry_t));
129 memset((caddr_t)mce, 0, sizeof(mntent_cache_entry_t));
130 mntent_cache_entry_hashtable[hash] = mce;
133 * Walk the linked list in the hash bucket.
135 for (mce = mntent_cache_entry_hashtable[hash]; mce->next != NULL; mce = mce->next) ;
136 mce->next = (mntent_cache_entry_t *)malloc(sizeof(mntent_cache_entry_t));
138 memset((caddr_t)mce, 0, sizeof(mntent_cache_entry_t));
142 mce->special = bstrdup(special);
143 mce->mountpoint = bstrdup(mountpoint);
144 mce->fstype = bstrdup(fstype);
146 mce->mntopts = bstrdup(mntopts);
151 * OS specific function to load the different mntents into the cache.
152 * This function should be called with a write lock on the mntent_cache.
154 static void refresh_mount_cache(void)
156 #if defined(HAVE_GETMNTENT)
159 #if defined(HAVE_LINUX_OS) || defined(HAVE_HPUX_OS) || defined(HAVE_IRIX_OS)
162 #if defined(HAVE_LINUX_OS)
163 if ((fp = setmntent("/proc/mounts", "r")) == (FILE *)NULL) {
164 if ((fp = setmntent(_PATH_MOUNTED, "r")) == (FILE *)NULL) {
168 #elif defined(HAVE_HPUX_OS)
169 if ((fp = fopen(MNT_MNTTAB, "r")) == (FILE *)NULL) {
172 #elif defined(HAVE_IRIX_OS)
173 if ((fp = setmntent(MOUNTED, "r")) == (FILE *)NULL) {
178 while ((mnt = getmntent(fp)) != (struct mntent *)NULL) {
179 if (stat(mnt->mnt_dir, &st) < 0) {
183 add_mntent_mapping(st.st_dev, mnt->mnt_fsname, mnt->mnt_dir, mnt->mnt_type, mnt->mnt_opts);
187 #elif defined(HAVE_SUN_OS)
190 if ((fp = fopen(MNTTAB, "r")) == (FILE *)NULL)
193 while (getmntent(fp, &mnt) == 0) {
194 if (stat(mnt.mnt_mountp, &st) < 0) {
198 add_mntent_mapping(st.st_dev, mnt.mnt_special, mnt.mnt_mountp, mnt.mnt_fstype, mnt.mnt_mntopts);
202 #endif /* HAVE_SUN_OS */
203 #elif defined(HAVE_GETMNTINFO)
206 #if defined(HAVE_DARWIN_OS)
207 struct statfs *mntinfo;
209 struct statvfs *mntinfo;
212 if ((cnt = getmntinfo(&mntinfo, MNT_NOWAIT)) > 0) {
214 if (stat(mntinfo->f_mntonname, &st) == 0) {
215 add_mntent_mapping(st.st_dev,
216 mntinfo->f_mntfromname,
217 mntinfo->f_mntonname,
218 mntinfo->f_fstypename,
225 #elif defined(HAVE_AIX_OS)
227 char *entries, *current;
233 if (mntctl(MCTL_QUERY, sizeof(bufsize), (struct vmount *)&bufsize) != 0) {
237 entries = malloc(bufsize);
238 if ((n_entries = mntctl(MCTL_QUERY, bufsize, (struct vmount *) entries)) < 0) {
245 while (cnt < n_entries) {
246 vmp = (struct vmount *)current;
248 if (stat(current + vmp->vmt_data[VMT_STUB].vmt_off, &st) < 0) {
252 ve = getvfsbytype(vmp->vmt_gfstype);
253 if (ve && ve->vfsent_name) {
254 add_mntent_mapping(st.st_dev,
255 current + vmp->vmt_data[VMT_OBJECT].vmt_off,
256 current + vmp->vmt_data[VMT_STUB].vmt_off,
258 current + vmp->vmt_data[VMT_ARGS].vmt_off);
260 current = current + vmp->vmt_length;
264 #elif defined(HAVE_OSF1_OS)
265 struct statfs *entries, *current;
270 if ((n_entries = getfsstat((struct statfs *)0, 0L, MNT_NOWAIT)) < 0) {
274 size = (n_entries + 1) * sizeof(struct statfs);
275 entries = malloc(size);
277 if ((n_entries = getfsstat(entries, size, MNT_NOWAIT)) < 0) {
284 while (cnt < n_entries) {
285 if (stat(current->f_mntonname, &st) < 0) {
288 add_mntent_mapping(st.st_dev,
289 current->f_mntfromname,
290 current->f_mntonname,
291 current->f_fstypename,
301 * Clear the cache (either by flushing it or by initializing it.)
302 * This function should be called with a write lock on the mntent_cache.
304 static void clear_mount_cache()
307 mntent_cache_entry_t *mce, *mce_next;
309 if (cache_initialized == 0) {
311 * Initialize the hash table.
313 memset((caddr_t)mntent_cache_entry_hashtable, 0, NR_MNTENT_CACHE_ENTRIES * sizeof(mntent_cache_entry_t *));
314 cache_initialized = 1;
317 * Clear the previous_cache_hit.
319 previous_cache_hit = NULL;
322 * Walk all hash buckets.
324 for (hash = 0; hash < NR_MNTENT_CACHE_ENTRIES; hash++) {
326 * Walk the content of this hash bucket.
328 mce = mntent_cache_entry_hashtable[hash];
329 mntent_cache_entry_hashtable[hash] = NULL;
330 while (mce != NULL) {
332 * Save the pointer to the next entry.
334 mce_next = mce->next;
337 * Free the structure.
342 free(mce->mountpoint);
353 * Initialize the cache for use.
355 static void initialize_mntent_cache(void)
358 * Lock the cache while we update it.
360 P(mntent_cache_lock);
363 * Make sure the cache is empty (either by flushing it or by initializing it.)
370 refresh_mount_cache();
373 * We are done updating the cache.
375 V(mntent_cache_lock);
378 void preload_mntent_cache(void)
380 initialize_mntent_cache();
383 void flush_mntent_cache(void)
386 * Lock the cache while we update it.
388 P(mntent_cache_lock);
391 * Make sure the cache is empty (either by flushing it or by initializing it.)
396 * We are done updating the cache.
398 V(mntent_cache_lock);
402 * Find a mapping in the cache.
404 mntent_cache_entry_t *find_mntent_mapping(uint32_t dev)
407 mntent_cache_entry_t *mce;
410 * Initialize the cache if that was not done before.
412 if (cache_initialized == 0) {
413 initialize_mntent_cache();
417 * Shortcut when we get a request for the same device again.
419 if (previous_cache_hit && previous_cache_hit->dev == dev) {
420 return previous_cache_hit;
424 * Lock the cache while we walk it.
426 P(mntent_cache_lock);
429 * Select the correct hash bucket.
431 hash = mntent_hash_function(dev);
434 * Walk the hash bucket.
436 for (mce = mntent_cache_entry_hashtable[hash]; mce != NULL; mce = mce->next) {
437 if (mce->dev == dev) {
438 previous_cache_hit = mce;
439 V(mntent_cache_lock);
445 * We are done walking the cache.
447 V(mntent_cache_lock);