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_OPENBSD_OS)
78 #include <sys/param.h>
79 #include <sys/mount.h>
80 #elif defined(HAVE_NETBSD_OS)
81 #include <sys/types.h>
82 #include <sys/statvfs.h>
84 #include <sys/param.h>
85 #include <sys/ucred.h>
86 #include <sys/mount.h>
88 #elif defined(HAVE_AIX_OS)
91 #elif defined(HAVE_OSF1_OS)
92 #include <sys/mount.h>
95 static char cache_initialized = 0;
98 * Protected data by mutex lock.
100 static pthread_mutex_t mntent_cache_lock = PTHREAD_MUTEX_INITIALIZER;
101 static mntent_cache_entry_t *mntent_cache_entry_hashtable[NR_MNTENT_CACHE_ENTRIES];
102 static mntent_cache_entry_t *previous_cache_hit = NULL;
105 * Simple hash function.
107 static uint32_t mntent_hash_function(uint32_t dev)
109 return (dev % NR_MNTENT_CACHE_ENTRIES);
113 * Add a new entry to the cache.
114 * This function should be called with a write lock on the mntent_cache.
116 static void add_mntent_mapping(uint32_t dev, const char *special, const char *mountpoint,
117 const char *fstype, const char *mntopts)
120 mntent_cache_entry_t *mce;
123 * Select the correct hash bucket.
125 hash = mntent_hash_function(dev);
128 * See if this is the first being put into the hash bucket.
130 if (mntent_cache_entry_hashtable[hash] == (mntent_cache_entry_t *)NULL) {
131 mce = (mntent_cache_entry_t *)malloc(sizeof(mntent_cache_entry_t));
132 memset((caddr_t)mce, 0, sizeof(mntent_cache_entry_t));
133 mntent_cache_entry_hashtable[hash] = mce;
136 * Walk the linked list in the hash bucket.
138 for (mce = mntent_cache_entry_hashtable[hash]; mce->next != NULL; mce = mce->next) ;
139 mce->next = (mntent_cache_entry_t *)malloc(sizeof(mntent_cache_entry_t));
141 memset((caddr_t)mce, 0, sizeof(mntent_cache_entry_t));
145 mce->special = bstrdup(special);
146 mce->mountpoint = bstrdup(mountpoint);
147 mce->fstype = bstrdup(fstype);
149 mce->mntopts = bstrdup(mntopts);
154 * OS specific function to load the different mntents into the cache.
155 * This function should be called with a write lock on the mntent_cache.
157 static void refresh_mount_cache(void)
159 #if defined(HAVE_GETMNTENT)
162 #if defined(HAVE_LINUX_OS) || defined(HAVE_HPUX_OS) || defined(HAVE_IRIX_OS)
165 #if defined(HAVE_LINUX_OS)
166 if ((fp = setmntent("/proc/mounts", "r")) == (FILE *)NULL) {
167 if ((fp = setmntent(_PATH_MOUNTED, "r")) == (FILE *)NULL) {
171 #elif defined(HAVE_HPUX_OS)
172 if ((fp = fopen(MNT_MNTTAB, "r")) == (FILE *)NULL) {
175 #elif defined(HAVE_IRIX_OS)
176 if ((fp = setmntent(MOUNTED, "r")) == (FILE *)NULL) {
181 while ((mnt = getmntent(fp)) != (struct mntent *)NULL) {
182 if (stat(mnt->mnt_dir, &st) < 0) {
186 add_mntent_mapping(st.st_dev, mnt->mnt_fsname, mnt->mnt_dir, mnt->mnt_type, mnt->mnt_opts);
190 #elif defined(HAVE_SUN_OS)
193 if ((fp = fopen(MNTTAB, "r")) == (FILE *)NULL)
196 while (getmntent(fp, &mnt) == 0) {
197 if (stat(mnt.mnt_mountp, &st) < 0) {
201 add_mntent_mapping(st.st_dev, mnt.mnt_special, mnt.mnt_mountp, mnt.mnt_fstype, mnt.mnt_mntopts);
205 #endif /* HAVE_SUN_OS */
206 #elif defined(HAVE_GETMNTINFO)
209 #if defined(HAVE_NETBSD_OS)
210 struct statvfs *mntinfo;
212 struct statfs *mntinfo;
214 #if defined(ST_NOWAIT)
215 int flags = ST_NOWAIT;
216 #elif defined(MNT_NOWAIT)
217 int flags = MNT_NOWAIT;
222 if ((cnt = getmntinfo(&mntinfo, flags)) > 0) {
224 if (stat(mntinfo->f_mntonname, &st) == 0) {
225 add_mntent_mapping(st.st_dev,
226 mntinfo->f_mntfromname,
227 mntinfo->f_mntonname,
228 mntinfo->f_fstypename,
235 #elif defined(HAVE_AIX_OS)
237 char *entries, *current;
243 if (mntctl(MCTL_QUERY, sizeof(bufsize), (struct vmount *)&bufsize) != 0) {
247 entries = malloc(bufsize);
248 if ((n_entries = mntctl(MCTL_QUERY, bufsize, (struct vmount *) entries)) < 0) {
255 while (cnt < n_entries) {
256 vmp = (struct vmount *)current;
258 if (stat(current + vmp->vmt_data[VMT_STUB].vmt_off, &st) < 0) {
262 ve = getvfsbytype(vmp->vmt_gfstype);
263 if (ve && ve->vfsent_name) {
264 add_mntent_mapping(st.st_dev,
265 current + vmp->vmt_data[VMT_OBJECT].vmt_off,
266 current + vmp->vmt_data[VMT_STUB].vmt_off,
268 current + vmp->vmt_data[VMT_ARGS].vmt_off);
270 current = current + vmp->vmt_length;
274 #elif defined(HAVE_OSF1_OS)
275 struct statfs *entries, *current;
280 if ((n_entries = getfsstat((struct statfs *)0, 0L, MNT_NOWAIT)) < 0) {
284 size = (n_entries + 1) * sizeof(struct statfs);
285 entries = malloc(size);
287 if ((n_entries = getfsstat(entries, size, MNT_NOWAIT)) < 0) {
294 while (cnt < n_entries) {
295 if (stat(current->f_mntonname, &st) < 0) {
298 add_mntent_mapping(st.st_dev,
299 current->f_mntfromname,
300 current->f_mntonname,
301 current->f_fstypename,
311 * Clear the cache (either by flushing it or by initializing it.)
312 * This function should be called with a write lock on the mntent_cache.
314 static void clear_mount_cache()
317 mntent_cache_entry_t *mce, *mce_next;
319 if (cache_initialized == 0) {
321 * Initialize the hash table.
323 memset((caddr_t)mntent_cache_entry_hashtable, 0, NR_MNTENT_CACHE_ENTRIES * sizeof(mntent_cache_entry_t *));
324 cache_initialized = 1;
327 * Clear the previous_cache_hit.
329 previous_cache_hit = NULL;
332 * Walk all hash buckets.
334 for (hash = 0; hash < NR_MNTENT_CACHE_ENTRIES; hash++) {
336 * Walk the content of this hash bucket.
338 mce = mntent_cache_entry_hashtable[hash];
339 mntent_cache_entry_hashtable[hash] = NULL;
340 while (mce != NULL) {
342 * Save the pointer to the next entry.
344 mce_next = mce->next;
347 * Free the structure.
352 free(mce->mountpoint);
363 * Initialize the cache for use.
365 static void initialize_mntent_cache(void)
368 * Lock the cache while we update it.
370 P(mntent_cache_lock);
373 * Make sure the cache is empty (either by flushing it or by initializing it.)
380 refresh_mount_cache();
383 * We are done updating the cache.
385 V(mntent_cache_lock);
388 void preload_mntent_cache(void)
390 initialize_mntent_cache();
393 void flush_mntent_cache(void)
396 * Lock the cache while we update it.
398 P(mntent_cache_lock);
401 * Make sure the cache is empty (either by flushing it or by initializing it.)
406 * We are done updating the cache.
408 V(mntent_cache_lock);
412 * Find a mapping in the cache.
414 mntent_cache_entry_t *find_mntent_mapping(uint32_t dev)
417 mntent_cache_entry_t *mce;
420 * Initialize the cache if that was not done before.
422 if (cache_initialized == 0) {
423 initialize_mntent_cache();
427 * Shortcut when we get a request for the same device again.
429 if (previous_cache_hit && previous_cache_hit->dev == dev) {
430 return previous_cache_hit;
434 * Lock the cache while we walk it.
436 P(mntent_cache_lock);
439 * Select the correct hash bucket.
441 hash = mntent_hash_function(dev);
444 * Walk the hash bucket.
446 for (mce = mntent_cache_entry_hashtable[hash]; mce != NULL; mce = mce->next) {
447 if (mce->dev == dev) {
448 previous_cache_hit = mce;
449 V(mntent_cache_lock);
455 * We are done walking the cache.
457 V(mntent_cache_lock);