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0bf836aa14
clang-tidy: avoid using 'else' after return - give more readable code, and also saves indention level.
344 lines
7.1 KiB
C
344 lines
7.1 KiB
C
/*
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* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "lib.h"
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#include "filter.h"
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#ifdef __linux__
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#include <sys/sysmacros.h>
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#include <dirent.h>
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static int _locate_sysfs_blocks(const char *sysfs_dir, char *path, size_t len,
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unsigned *sysfs_depth)
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{
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struct stat info;
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unsigned i;
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static const struct dir_class {
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const char path[32];
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int depth;
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} classes[] = {
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/*
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* unified classification directory for all kernel subsystems
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*
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* /sys/subsystem/block/devices
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* |-- sda -> ../../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda
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* |-- sda1 -> ../../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/sda1
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* `-- sr0 -> ../../../devices/pci0000:00/0000:00:1f.2/host1/target1:0:0/1:0:0:0/block/sr0
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*
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*/
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{ "subsystem/block/devices", 0 },
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/*
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* block subsystem as a class
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*
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* /sys/class/block
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* |-- sda -> ../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda
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* |-- sda1 -> ../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/sda1
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* `-- sr0 -> ../../devices/pci0000:00/0000:00:1f.2/host1/target1:0:0/1:0:0:0/block/sr0
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*
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*/
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{ "class/block", 0 },
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/*
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* old block subsystem layout with nested directories
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*
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* /sys/block/
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* |-- sda
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* | |-- capability
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* | |-- dev
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* ...
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* | |-- sda1
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* | | |-- dev
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* ...
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* |
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* `-- sr0
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* |-- capability
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* |-- dev
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* ...
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*
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*/
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{ "block", 1 }
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};
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for (i = 0; i < DM_ARRAY_SIZE(classes); ++i)
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if ((dm_snprintf(path, len, "%s%s", sysfs_dir, classes[i].path) >= 0) &&
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(stat(path, &info) == 0)) {
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*sysfs_depth = classes[i].depth;
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return 1;
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}
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return 0;
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}
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/*----------------------------------------------------------------
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* We need to store a set of dev_t.
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*--------------------------------------------------------------*/
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struct entry {
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struct entry *next;
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dev_t dev;
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};
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#define SET_BUCKETS 64
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struct dev_set {
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struct dm_pool *mem;
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const char *sys_block;
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unsigned sysfs_depth;
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int initialised;
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struct entry *slots[SET_BUCKETS];
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};
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static struct dev_set *_dev_set_create(struct dm_pool *mem,
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const char *sys_block,
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unsigned sysfs_depth)
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{
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struct dev_set *ds;
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if (!(ds = dm_pool_zalloc(mem, sizeof(*ds))))
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return NULL;
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ds->mem = mem;
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if (!(ds->sys_block = dm_pool_strdup(mem, sys_block)))
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return NULL;
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ds->sysfs_depth = sysfs_depth;
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ds->initialised = 0;
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return ds;
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}
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static unsigned _hash_dev(dev_t dev)
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{
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return (major(dev) ^ minor(dev)) & (SET_BUCKETS - 1);
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}
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/*
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* Doesn't check that the set already contains dev.
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*/
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static int _set_insert(struct dev_set *ds, dev_t dev)
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{
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struct entry *e;
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unsigned h = _hash_dev(dev);
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if (!(e = dm_pool_alloc(ds->mem, sizeof(*e))))
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return 0;
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e->next = ds->slots[h];
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e->dev = dev;
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ds->slots[h] = e;
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return 1;
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}
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static int _set_lookup(struct dev_set *ds, dev_t dev)
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{
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unsigned h = _hash_dev(dev);
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struct entry *e;
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for (e = ds->slots[h]; e; e = e->next)
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if (e->dev == dev)
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return 1;
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return 0;
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}
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/*----------------------------------------------------------------
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* filter methods
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*--------------------------------------------------------------*/
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static int _parse_dev(const char *file, FILE *fp, dev_t *result)
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{
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unsigned major, minor;
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char buffer[64];
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if (!fgets(buffer, sizeof(buffer), fp)) {
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log_error("Empty sysfs device file: %s", file);
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return 0;
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}
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if (sscanf(buffer, "%u:%u", &major, &minor) != 2) {
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log_error("Incorrect format for sysfs device file: %s.", file);
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return 0;
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}
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*result = makedev(major, minor);
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return 1;
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}
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static int _read_dev(const char *file, dev_t *result)
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{
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int r;
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FILE *fp;
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if (!(fp = fopen(file, "r"))) {
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log_sys_error("fopen", file);
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return 0;
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}
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r = _parse_dev(file, fp, result);
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if (fclose(fp))
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log_sys_error("fclose", file);
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return r;
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}
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/*
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* Recurse through sysfs directories, inserting any devs found.
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*/
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static int _read_devs(struct dev_set *ds, const char *dir, unsigned sysfs_depth)
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{
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struct dirent *d;
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DIR *dr;
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struct stat info;
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char path[PATH_MAX];
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char file[PATH_MAX];
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dev_t dev = { 0 };
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int r = 1;
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if (!(dr = opendir(dir))) {
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log_sys_error("opendir", dir);
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return 0;
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}
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while ((d = readdir(dr))) {
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if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
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continue;
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if (dm_snprintf(path, sizeof(path), "%s/%s", dir,
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d->d_name) < 0) {
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log_error("sysfs path name too long: %s in %s",
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d->d_name, dir);
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continue;
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}
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/* devices have a "dev" file */
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if (dm_snprintf(file, sizeof(file), "%s/dev", path) < 0) {
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log_error("sysfs path name too long: %s in %s",
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d->d_name, dir);
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continue;
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}
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if (!stat(file, &info)) {
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/* recurse if we found a device and expect subdirs */
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if (sysfs_depth)
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_read_devs(ds, path, sysfs_depth - 1);
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/* add the device we have found */
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if (_read_dev(file, &dev))
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_set_insert(ds, dev);
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}
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}
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if (closedir(dr))
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log_sys_error("closedir", dir);
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return r;
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}
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static int _init_devs(struct dev_set *ds)
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{
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if (!_read_devs(ds, ds->sys_block, ds->sysfs_depth)) {
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ds->initialised = -1;
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return 0;
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}
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ds->initialised = 1;
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return 1;
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}
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static int _accept_p(struct dev_filter *f, struct device *dev)
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{
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struct dev_set *ds = (struct dev_set *) f->private;
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if (!ds->initialised)
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_init_devs(ds);
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/* Pass through if initialisation failed */
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if (ds->initialised != 1)
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return 1;
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if (!_set_lookup(ds, dev->dev)) {
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log_debug_devs("%s: Skipping (sysfs)", dev_name(dev));
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return 0;
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}
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return 1;
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}
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static void _destroy(struct dev_filter *f)
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{
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struct dev_set *ds = (struct dev_set *) f->private;
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if (f->use_count)
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log_error(INTERNAL_ERROR "Destroying sysfs filter while in use %u times.", f->use_count);
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dm_pool_destroy(ds->mem);
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}
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struct dev_filter *sysfs_filter_create(void)
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{
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const char *sysfs_dir = dm_sysfs_dir();
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char sys_block[PATH_MAX];
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unsigned sysfs_depth;
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struct dm_pool *mem;
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struct dev_set *ds;
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struct dev_filter *f;
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if (!*sysfs_dir) {
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log_verbose("No proc filesystem found: skipping sysfs filter");
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return NULL;
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}
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if (!_locate_sysfs_blocks(sysfs_dir, sys_block, sizeof(sys_block), &sysfs_depth))
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return NULL;
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if (!(mem = dm_pool_create("sysfs", 256))) {
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log_error("sysfs pool creation failed");
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return NULL;
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}
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if (!(ds = _dev_set_create(mem, sys_block, sysfs_depth))) {
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log_error("sysfs dev_set creation failed");
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goto bad;
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}
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if (!(f = dm_pool_zalloc(mem, sizeof(*f))))
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goto_bad;
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f->passes_filter = _accept_p;
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f->destroy = _destroy;
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f->use_count = 0;
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f->private = ds;
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log_debug_devs("Sysfs filter initialised.");
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return f;
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bad:
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dm_pool_destroy(mem);
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return NULL;
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}
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#else
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struct dev_filter *sysfs_filter_create(const char *sysfs_dir __attribute__((unused)))
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{
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return NULL;
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}
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#endif
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