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mirror of git://sourceware.org/git/lvm2.git synced 2024-12-22 17:35:59 +03:00
lvm2/lib/device/dev-cache.c
Alasdair Kergon 8a2fc58645 Check for libsepol.
Add some cflow & scope support.
Separate out DEFS from CFLAGS.
Remove inlines and use unique function names.
2006-04-19 15:33:07 +00:00

696 lines
14 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "dev-cache.h"
#include "lvm-types.h"
#include "btree.h"
#include "filter.h"
#include "filter-persistent.h"
#include <unistd.h>
#include <sys/param.h>
#include <dirent.h>
struct dev_iter {
struct btree_iter *current;
struct dev_filter *filter;
};
struct dir_list {
struct list list;
char dir[0];
};
static struct {
struct dm_pool *mem;
struct dm_hash_table *names;
struct btree *devices;
int has_scanned;
struct list dirs;
struct list files;
} _cache;
#define _alloc(x) dm_pool_zalloc(_cache.mem, (x))
#define _free(x) dm_pool_free(_cache.mem, (x))
#define _strdup(x) dm_pool_strdup(_cache.mem, (x))
static int _insert(const char *path, int rec);
struct device *dev_create_file(const char *filename, struct device *dev,
struct str_list *alias, int use_malloc)
{
int allocate = !dev;
if (allocate) {
if (use_malloc) {
if (!(dev = dm_malloc(sizeof(*dev)))) {
log_error("struct device allocation failed");
return NULL;
}
if (!(alias = dm_malloc(sizeof(*alias)))) {
log_error("struct str_list allocation failed");
dm_free(dev);
return NULL;
}
if (!(alias->str = dm_strdup(filename))) {
log_error("filename strdup failed");
dm_free(dev);
dm_free(alias);
return NULL;
}
dev->flags = DEV_ALLOCED;
} else {
if (!(dev = _alloc(sizeof(*dev)))) {
log_error("struct device allocation failed");
return NULL;
}
if (!(alias = _alloc(sizeof(*alias)))) {
log_error("struct str_list allocation failed");
_free(dev);
return NULL;
}
if (!(alias->str = _strdup(filename))) {
log_error("filename strdup failed");
return NULL;
}
}
} else if (!(alias->str = dm_strdup(filename))) {
log_error("filename strdup failed");
return NULL;
}
dev->flags |= DEV_REGULAR;
list_init(&dev->aliases);
list_add(&dev->aliases, &alias->list);
dev->end = UINT64_C(0);
dev->dev = 0;
dev->fd = -1;
dev->open_count = 0;
dev->block_size = -1;
memset(dev->pvid, 0, sizeof(dev->pvid));
list_init(&dev->open_list);
return dev;
}
static struct device *_dev_create(dev_t d)
{
struct device *dev;
if (!(dev = _alloc(sizeof(*dev)))) {
log_error("struct device allocation failed");
return NULL;
}
dev->flags = 0;
list_init(&dev->aliases);
dev->dev = d;
dev->fd = -1;
dev->open_count = 0;
dev->block_size = -1;
dev->end = UINT64_C(0);
memset(dev->pvid, 0, sizeof(dev->pvid));
list_init(&dev->open_list);
return dev;
}
/* Return 1 if we prefer path1 else return 0 */
static int _compare_paths(const char *path0, const char *path1)
{
int slash0 = 0, slash1 = 0;
const char *p;
char p0[PATH_MAX], p1[PATH_MAX];
char *s0, *s1;
struct stat stat0, stat1;
/* Return the path with fewer slashes */
for (p = path0; p++; p = (const char *) strchr(p, '/'))
slash0++;
for (p = path1; p++; p = (const char *) strchr(p, '/'))
slash1++;
if (slash0 < slash1)
return 0;
if (slash1 < slash0)
return 1;
strncpy(p0, path0, PATH_MAX);
strncpy(p1, path1, PATH_MAX);
s0 = &p0[0] + 1;
s1 = &p1[0] + 1;
/* We prefer symlinks - they exist for a reason!
* So we prefer a shorter path before the first symlink in the name.
* FIXME Configuration option to invert this? */
while (s0) {
s0 = strchr(s0, '/');
s1 = strchr(s1, '/');
if (s0) {
*s0 = '\0';
*s1 = '\0';
}
if (lstat(p0, &stat0)) {
log_sys_error("lstat", p0);
return 1;
}
if (lstat(p1, &stat1)) {
log_sys_error("lstat", p1);
return 0;
}
if (S_ISLNK(stat0.st_mode) && !S_ISLNK(stat1.st_mode))
return 0;
if (!S_ISLNK(stat0.st_mode) && S_ISLNK(stat1.st_mode))
return 1;
if (s0) {
*s0++ = '/';
*s1++ = '/';
}
}
/* ASCII comparison */
if (strcmp(path0, path1) < 0)
return 0;
else
return 1;
}
static int _add_alias(struct device *dev, const char *path)
{
struct str_list *sl = _alloc(sizeof(*sl));
struct str_list *strl;
const char *oldpath;
int prefer_old = 1;
if (!sl) {
stack;
return 0;
}
/* Is name already there? */
list_iterate_items(strl, &dev->aliases) {
if (!strcmp(strl->str, path)) {
log_debug("%s: Already in device cache", path);
return 1;
}
}
if (!(sl->str = dm_pool_strdup(_cache.mem, path))) {
stack;
return 0;
}
if (!list_empty(&dev->aliases)) {
oldpath = list_item(dev->aliases.n, struct str_list)->str;
prefer_old = _compare_paths(path, oldpath);
log_debug("%s: Aliased to %s in device cache%s",
path, oldpath, prefer_old ? "" : " (preferred name)");
} else
log_debug("%s: Added to device cache", path);
if (prefer_old)
list_add(&dev->aliases, &sl->list);
else
list_add_h(&dev->aliases, &sl->list);
return 1;
}
/*
* Either creates a new dev, or adds an alias to
* an existing dev.
*/
static int _insert_dev(const char *path, dev_t d)
{
struct device *dev;
static dev_t loopfile_count = 0;
int loopfile = 0;
/* Generate pretend device numbers for loopfiles */
if (!d) {
if (dm_hash_lookup(_cache.names, path))
return 1;
d = ++loopfile_count;
loopfile = 1;
}
/* is this device already registered ? */
if (!(dev = (struct device *) btree_lookup(_cache.devices,
(uint32_t) d))) {
/* create new device */
if (loopfile) {
if (!(dev = dev_create_file(path, NULL, NULL, 0))) {
stack;
return 0;
}
} else if (!(dev = _dev_create(d))) {
stack;
return 0;
}
if (!(btree_insert(_cache.devices, (uint32_t) d, dev))) {
log_err("Couldn't insert device into binary tree.");
_free(dev);
return 0;
}
}
if (!loopfile && !_add_alias(dev, path)) {
log_err("Couldn't add alias to dev cache.");
return 0;
}
if (!dm_hash_insert(_cache.names, path, dev)) {
log_err("Couldn't add name to hash in dev cache.");
return 0;
}
return 1;
}
static char *_join(const char *dir, const char *name)
{
size_t len = strlen(dir) + strlen(name) + 2;
char *r = dm_malloc(len);
if (r)
snprintf(r, len, "%s/%s", dir, name);
return r;
}
/*
* Get rid of extra slashes in the path string.
*/
static void _collapse_slashes(char *str)
{
char *ptr;
int was_slash = 0;
for (ptr = str; *ptr; ptr++) {
if (*ptr == '/') {
if (was_slash)
continue;
was_slash = 1;
} else
was_slash = 0;
*str++ = *ptr;
}
*str = *ptr;
}
static int _insert_dir(const char *dir)
{
int n, dirent_count, r = 1;
struct dirent **dirent;
char *path;
dirent_count = scandir(dir, &dirent, NULL, alphasort);
if (dirent_count > 0) {
for (n = 0; n < dirent_count; n++) {
if (dirent[n]->d_name[0] == '.') {
free(dirent[n]);
continue;
}
if (!(path = _join(dir, dirent[n]->d_name))) {
stack;
return 0;
}
_collapse_slashes(path);
r &= _insert(path, 1);
dm_free(path);
free(dirent[n]);
}
free(dirent);
}
return r;
}
static int _insert_file(const char *path)
{
struct stat info;
if (stat(path, &info) < 0) {
log_sys_very_verbose("stat", path);
return 0;
}
if (!S_ISREG(info.st_mode)) {
log_debug("%s: Not a regular file", path);
return 0;
}
if (!_insert_dev(path, 0)) {
stack;
return 0;
}
return 1;
}
static int _insert(const char *path, int rec)
{
struct stat info;
int r = 0;
if (stat(path, &info) < 0) {
log_sys_very_verbose("stat", path);
return 0;
}
if (S_ISDIR(info.st_mode)) { /* add a directory */
/* check it's not a symbolic link */
if (lstat(path, &info) < 0) {
log_sys_very_verbose("lstat", path);
return 0;
}
if (S_ISLNK(info.st_mode)) {
log_debug("%s: Symbolic link to directory", path);
return 0;
}
if (rec)
r = _insert_dir(path);
} else { /* add a device */
if (!S_ISBLK(info.st_mode)) {
log_debug("%s: Not a block device", path);
return 0;
}
if (!_insert_dev(path, info.st_rdev)) {
stack;
return 0;
}
r = 1;
}
return r;
}
static void _full_scan(int dev_scan)
{
struct dir_list *dl;
if (_cache.has_scanned && !dev_scan)
return;
list_iterate_items(dl, &_cache.dirs)
_insert_dir(dl->dir);
list_iterate_items(dl, &_cache.files)
_insert_file(dl->dir);
_cache.has_scanned = 1;
init_full_scan_done(1);
}
int dev_cache_has_scanned(void)
{
return _cache.has_scanned;
}
void dev_cache_scan(int do_scan)
{
if (!do_scan)
_cache.has_scanned = 1;
else
_full_scan(1);
}
int dev_cache_init(void)
{
_cache.names = NULL;
_cache.has_scanned = 0;
if (!(_cache.mem = dm_pool_create("dev_cache", 10 * 1024))) {
stack;
return 0;
}
if (!(_cache.names = dm_hash_create(128))) {
stack;
dm_pool_destroy(_cache.mem);
_cache.mem = 0;
return 0;
}
if (!(_cache.devices = btree_create(_cache.mem))) {
log_err("Couldn't create binary tree for dev-cache.");
goto bad;
}
list_init(&_cache.dirs);
list_init(&_cache.files);
return 1;
bad:
dev_cache_exit();
return 0;
}
static void _check_closed(struct device *dev)
{
if (dev->fd >= 0)
log_err("Device '%s' has been left open.", dev_name(dev));
}
static void _check_for_open_devices(void)
{
dm_hash_iter(_cache.names, (dm_hash_iterate_fn) _check_closed);
}
void dev_cache_exit(void)
{
if (_cache.names)
_check_for_open_devices();
if (_cache.mem) {
dm_pool_destroy(_cache.mem);
_cache.mem = NULL;
}
if (_cache.names) {
dm_hash_destroy(_cache.names);
_cache.names = NULL;
}
_cache.devices = NULL;
_cache.has_scanned = 0;
list_init(&_cache.dirs);
list_init(&_cache.files);
}
int dev_cache_add_dir(const char *path)
{
struct dir_list *dl;
struct stat st;
if (stat(path, &st)) {
log_error("Ignoring %s: %s", path, strerror(errno));
/* But don't fail */
return 1;
}
if (!S_ISDIR(st.st_mode)) {
log_error("Ignoring %s: Not a directory", path);
return 1;
}
if (!(dl = _alloc(sizeof(*dl) + strlen(path) + 1))) {
log_error("dir_list allocation failed");
return 0;
}
strcpy(dl->dir, path);
list_add(&_cache.dirs, &dl->list);
return 1;
}
int dev_cache_add_loopfile(const char *path)
{
struct dir_list *dl;
struct stat st;
if (stat(path, &st)) {
log_error("Ignoring %s: %s", path, strerror(errno));
/* But don't fail */
return 1;
}
if (!S_ISREG(st.st_mode)) {
log_error("Ignoring %s: Not a regular file", path);
return 1;
}
if (!(dl = _alloc(sizeof(*dl) + strlen(path) + 1))) {
log_error("dir_list allocation failed for file");
return 0;
}
strcpy(dl->dir, path);
list_add(&_cache.files, &dl->list);
return 1;
}
/* Check cached device name is still valid before returning it */
/* This should be a rare occurrence */
/* set quiet if the cache is expected to be out-of-date */
/* FIXME Make rest of code pass/cache struct device instead of dev_name */
const char *dev_name_confirmed(struct device *dev, int quiet)
{
struct stat buf;
const char *name;
int r;
if ((dev->flags & DEV_REGULAR))
return dev_name(dev);
while ((r = stat(name = list_item(dev->aliases.n,
struct str_list)->str, &buf)) ||
(buf.st_rdev != dev->dev)) {
if (r < 0) {
if (quiet)
log_sys_debug("stat", name);
else
log_sys_error("stat", name);
}
if (quiet)
log_debug("Path %s no longer valid for device(%d,%d)",
name, (int) MAJOR(dev->dev),
(int) MINOR(dev->dev));
else
log_error("Path %s no longer valid for device(%d,%d)",
name, (int) MAJOR(dev->dev),
(int) MINOR(dev->dev));
/* Remove the incorrect hash entry */
dm_hash_remove(_cache.names, name);
/* Leave list alone if there isn't an alternative name */
/* so dev_name will always find something to return. */
/* Otherwise add the name to the correct device. */
if (list_size(&dev->aliases) > 1) {
list_del(dev->aliases.n);
if (!r)
_insert(name, 0);
continue;
}
log_error("Aborting - please provide new pathname for what "
"used to be %s", name);
return NULL;
}
return dev_name(dev);
}
struct device *dev_cache_get(const char *name, struct dev_filter *f)
{
struct stat buf;
struct device *d = (struct device *) dm_hash_lookup(_cache.names, name);
if (d && (d->flags & DEV_REGULAR))
return d;
/* If the entry's wrong, remove it */
if (d && (stat(name, &buf) || (buf.st_rdev != d->dev))) {
dm_hash_remove(_cache.names, name);
d = NULL;
}
if (!d) {
_insert(name, 0);
d = (struct device *) dm_hash_lookup(_cache.names, name);
if (!d) {
_full_scan(0);
d = (struct device *) dm_hash_lookup(_cache.names, name);
}
}
return (d && (!f || (d->flags & DEV_REGULAR) ||
f->passes_filter(f, d))) ? d : NULL;
}
struct dev_iter *dev_iter_create(struct dev_filter *f, int dev_scan)
{
struct dev_iter *di = dm_malloc(sizeof(*di));
if (!di) {
log_error("dev_iter allocation failed");
return NULL;
}
if (dev_scan) {
/* Flag gets reset between each command */
if (!full_scan_done())
persistent_filter_wipe(f); /* Calls _full_scan(1) */
} else
_full_scan(0);
di->current = btree_first(_cache.devices);
di->filter = f;
return di;
}
void dev_iter_destroy(struct dev_iter *iter)
{
dm_free(iter);
}
static struct device *_iter_next(struct dev_iter *iter)
{
struct device *d = btree_get_data(iter->current);
iter->current = btree_next(iter->current);
return d;
}
struct device *dev_iter_get(struct dev_iter *iter)
{
while (iter->current) {
struct device *d = _iter_next(iter);
if (!iter->filter || (d->flags & DEV_REGULAR) ||
iter->filter->passes_filter(iter->filter, d))
return d;
}
return NULL;
}
int dev_fd(struct device *dev)
{
return dev->fd;
}
const char *dev_name(const struct device *dev)
{
return (dev) ? list_item(dev->aliases.n, struct str_list)->str :
"unknown device";
}