Sysfs block device filtering option for 2.6.

doc/example.conf

@@ -61,6 +61,10 @@ devices {
     # List of pairs of additional acceptable block device types found 
     # in /proc/devices with maximum (non-zero) number of partitions.
     # types = [ "fd", 16 ]
+
+    # If sysfs is mounted (2.6 kernels) restrict device scanning to 
+    # the block devices it believes are valid.
+    sysfs_scan = 1	
 }
 
 # This section that allows you to configure the nature of the

include/.symlinks

@@ -16,6 +16,7 @@
 ../lib/filters/filter-composite.h
 ../lib/filters/filter-persistent.h
 ../lib/filters/filter-regex.h
+../lib/filters/filter-sysfs.h
 ../lib/filters/filter.h
 ../lib/format1/format1.h
 ../lib/format_text/format-text.h

lib/Makefile.in

@@ -28,6 +28,7 @@ SOURCES=\
 	filters/filter-composite.c \
 	filters/filter-persistent.c \
 	filters/filter-regex.c \
+	filters/filter-sysfs.c \
 	filters/filter.c \
 	format_text/archive.c \
 	format_text/export.c \

lib/commands/toolcontext.c

@@ -16,6 +16,7 @@
 #include "filter-composite.h"
 #include "filter-persistent.h"
 #include "filter-regex.h"
+#include "filter-sysfs.h"
 #include "label.h"
 #include "lvm-file.h"
 #include "format-text.h"
@@ -261,33 +262,43 @@ static int _init_dev_cache(struct cmd_context *cmd)
 	return 1;
 }
 
+#define MAX_FILTERS 3
+
 static struct dev_filter *_init_filter_components(struct cmd_context *cmd)
 {
+	unsigned nr_filt = 0;
 	struct config_node *cn;
-	struct dev_filter *f1, *f2, *f3;
+	struct dev_filter *filters[MAX_FILTERS];
 
-	cn = find_config_node(cmd->cf->root, "devices/types", '/');
+	memset(filters, 0, sizeof(filters));
 
-	if (!(f2 = lvm_type_filter_create(cmd->proc_dir, cn)))
-		return NULL;
-
-	if (!(cn = find_config_node(cmd->cf->root, "devices/filter", '/'))) {
-		log_debug("devices/filter not found in config file: no regex "
-			  "filter installed");
-		return f2;
+	/* sysfs filter */
+	if (find_config_bool(cmd->cf->root, "devices/sysfs_scan", '/',
+			     DEFAULT_SYSFS_SCAN)) {
+		if ((filters[nr_filt] = sysfs_filter_create(cmd->proc_dir)))
+			nr_filt++;
 	}
 
-	if (!(f1 = regex_filter_create(cn->v))) {
+	/* regex filter */
+	if (!(cn = find_config_node(cmd->cf->root, "devices/filter", '/')))
+		log_debug("devices/filter not found in config file: no regex "
+			  "filter installed");
+
+	else if (!(filters[nr_filt++] = regex_filter_create(cn->v))) {
 		log_error("Failed to create regex device filter");
 		return NULL;
 	}
 
-	if (!(f3 = composite_filter_create(2, f1, f2))) {
-		log_error("Failed to create composite device filter");
+	/* device type filter */
+	cn = find_config_node(cmd->cf->root, "devices/types", '/');
+	if (!(filters[nr_filt++] = lvm_type_filter_create(cmd->proc_dir, cn))) {
+		log_error("Failed to create lvm type filter");
 		return NULL;
 	}
 
-	return f3;
+	/* only build a composite filter if we really need it */
+	return (nr_filt == 1) ?
+	    filters[0] : composite_filter_create(nr_filt, filters);
 }
 
 static int _init_filters(struct cmd_context *cmd)

lib/config/defaults.h

@@ -19,6 +19,7 @@
 #define DEFAULT_SYS_DIR "/etc/lvm"
 #define DEFAULT_DEV_DIR "/dev"
 #define DEFAULT_PROC_DIR "/proc"
+#define DEFAULT_SYSFS_SCAN 1
 
 #define DEFAULT_LOCK_DIR "/var/lock/lvm"
 #define DEFAULT_LOCKING_LIB "lvm2_locking.so"

lib/filters/filter-composite.c

@@ -37,35 +37,32 @@ static void _destroy(struct dev_filter *f)
 	dbg_free(f);
 }
 
-struct dev_filter *composite_filter_create(int n, ...)
+struct dev_filter *composite_filter_create(int n, struct dev_filter **filters)
 {
-	struct dev_filter **filters = dbg_malloc(sizeof(*filters) * (n + 1));
-	struct dev_filter *cf;
-	va_list ap;
-	int i;
+	struct dev_filter **filters_copy, *cf;
 
 	if (!filters) {
 		stack;
 		return NULL;
 	}
 
-	if (!(cf = dbg_malloc(sizeof(*cf)))) {
-		stack;
-		dbg_free(filters);
+	if (!(filters_copy = dbg_malloc(sizeof(*filters) * (n + 1)))) {
+		log_error("composite filters allocation failed");
 		return NULL;
 	}
 
-	va_start(ap, n);
-	for (i = 0; i < n; i++) {
-		struct dev_filter *f = va_arg(ap, struct dev_filter *);
-		filters[i] = f;
+	memcpy(filters_copy, filters, sizeof(*filters) * n);
+	filters_copy[n] = NULL;
+
+	if (!(cf = dbg_malloc(sizeof(*cf)))) {
+		log_error("compsoite filters allocation failed");
+		dbg_free(filters_copy);
+		return NULL;
 	}
-	filters[i] = NULL;
-	va_end(ap);
 
 	cf->passes_filter = _and_p;
 	cf->destroy = _destroy;
-	cf->private = filters;
+	cf->private = filters_copy;
 
 	return cf;
 }

lib/filters/filter-composite.h

@@ -9,6 +9,6 @@
 
 #include "dev-cache.h"
 
-struct dev_filter *composite_filter_create(int n, ...);
+struct dev_filter *composite_filter_create(int n, struct dev_filter **filters);
 
 #endif

lib/filters/filter-sysfs.c

@@ -0,0 +1,273 @@
+/*
+ * Copyright (C) 2004 Red Hat Inc
+ *
+ * This file is released under the GPL.
+ */
+
+#include "lib.h"
+#include "filter-sysfs.h"
+#include "lvm-string.h"
+#include "pool.h"
+
+#include <sys/sysmacros.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <dirent.h>
+
+static int _locate_sysfs_blocks(const char *proc, char *path, size_t len)
+{
+	char proc_mounts[PATH_MAX];
+	int r = 0;
+	FILE *fp;
+	char *split[2], buffer[PATH_MAX + 16];
+
+	if (!*proc) {
+		log_verbose("No proc filesystem found: skipping sysfs filter");
+		return 0;
+	}
+		
+	if (lvm_snprintf(proc_mounts, sizeof(proc_mounts),
+			 "%s/mounts", proc) < 0) {
+		log_error("Failed to create /proc/mounts string");
+		return 0;
+	}
+
+	if (!(fp = fopen(proc_mounts, "r"))) {
+		log_sys_error("fopen %s", proc_mounts);
+		return 0;
+	}
+
+	while (fgets(buffer, sizeof(buffer), fp)) {
+		if (split_words(buffer, 2, split) == 2 &&
+		    !strcmp(split[0], "sysfs")) {
+			if (lvm_snprintf(path, len, "%s/%s", split[1],
+					 "block") >= 0) {
+				r = 1;
+			}
+			break;
+		}
+	}
+
+	fclose(fp);
+	return r;
+}
+
+/*----------------------------------------------------------------
+ * We need to store a set of dev_t.
+ *--------------------------------------------------------------*/
+struct entry {
+	struct entry *next;
+	dev_t dev;
+};
+
+#define SET_BUCKETS 64
+struct dev_set {
+	struct pool *mem;
+	const char *sys_block;
+	int initialised;
+	struct entry *slots[SET_BUCKETS];
+};
+
+static struct dev_set *_dev_set_create(struct pool *mem, const char *sys_block)
+{
+	struct dev_set *ds;
+
+	if (!(ds = pool_zalloc(mem, sizeof(*ds))))
+		return NULL;
+
+	ds->mem = mem;
+	ds->sys_block = pool_strdup(mem, sys_block);
+	ds->initialised = 0;
+
+	return ds;
+}
+
+static inline unsigned _hash_dev(dev_t dev)
+{
+	return (major(dev) ^ minor(dev)) & (SET_BUCKETS - 1);
+}
+
+/*
+ * Doesn't check that the set already contains dev.
+ */
+static int _set_insert(struct dev_set *ds, dev_t dev)
+{
+	struct entry *e;
+	unsigned h = _hash_dev(dev);
+
+	if (!(e = pool_alloc(ds->mem, sizeof(*e))))
+		return 0;
+
+	e->next = ds->slots[h];
+	e->dev = dev;
+	ds->slots[h] = e;
+
+	return 1;
+}
+
+static int _set_lookup(struct dev_set *ds, dev_t dev)
+{
+	unsigned h = _hash_dev(dev);
+	struct entry *e;
+
+	for (e = ds->slots[h]; e; e = e->next)
+		if (e->dev == dev)
+			return 1;
+
+	return 0;
+}
+
+/*----------------------------------------------------------------
+ * filter methods
+ *--------------------------------------------------------------*/
+static int _parse_dev(const char *file, FILE *fp, dev_t *result)
+{
+	unsigned major, minor;
+	char buffer[64];
+
+	if (!fgets(buffer, sizeof(buffer), fp)) {
+		log_error("Empty sysfs device file: %s", file);
+		return 0;
+	}
+
+	if (sscanf(buffer, "%u:%u", &major, &minor) != 2) {
+		log_info("sysfs device file not correct format");
+		return 0;
+	}
+
+	*result = makedev(major, minor);
+	return 1;
+}
+
+static int _read_dev(const char *file, dev_t *result)
+{
+	int r;
+	FILE *fp;
+
+	if (!(fp = fopen(file, "r"))) {
+		log_sys_error("fopen", file);
+		return 0;
+	}
+
+	r = _parse_dev(file, fp, result);
+	fclose(fp);
+
+	return r;
+}
+
+/*
+ * Recurse through sysfs directories, inserting any devs found.
+ */
+static int _read_devs(struct dev_set *ds, const char *dir)
+{
+        struct dirent *d;
+        DIR *dr;
+	char path[PATH_MAX];
+	dev_t dev;
+	int r = 1;
+
+        if (!(dr = opendir(dir))) {
+                log_sys_error("opendir", dir);
+                return 0;
+        }
+
+        while ((d = readdir(dr))) {
+                if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+
+		if (lvm_snprintf(path, sizeof(path), "%s/%s", dir,
+				 d->d_name) < 0) {
+			log_error("sysfs path name too long: %s in %s",
+				  d->d_name, dir);
+			continue;
+		}
+
+		if (d->d_type == DT_DIR) {
+			if (!_read_devs(ds, path)) {
+				r = 0;
+				break;
+			}
+		}
+
+		if ((d->d_type == DT_REG && !strcmp(d->d_name, "dev")))
+			if (!_read_dev(path, &dev) || !_set_insert(ds, dev)) {
+				r = 0;
+				break;
+			}
+
+	}
+
+        if (closedir(dr))
+                log_sys_error("closedir", dir);
+
+	return r;
+}
+
+static int _init_devs(struct dev_set *ds)
+{
+	if (!_read_devs(ds, ds->sys_block)) {
+		ds->initialised = -1;
+		return 0;
+	}
+
+	ds->initialised = 1;
+
+	return 1;
+}
+
+
+static int _accept_p(struct dev_filter *f, struct device *dev)
+{
+	struct dev_set *ds = (struct dev_set *) f->private;
+
+	if (!ds->initialised)
+		_init_devs(ds);
+
+	/* Pass through if initialisation failed */
+	if (ds->initialised != 1)
+		return 1;
+
+	return _set_lookup(ds, dev->dev);
+}
+
+static void _destroy(struct dev_filter *f)
+{
+	struct dev_set *ds = (struct dev_set *) f->private;
+	pool_destroy(ds->mem);
+}
+
+struct dev_filter *sysfs_filter_create(const char *proc)
+{
+	char sys_block[PATH_MAX];
+	struct pool *mem;
+	struct dev_set *ds;
+	struct dev_filter *f;
+
+	if (!_locate_sysfs_blocks(proc, sys_block, sizeof(sys_block)))
+		return NULL;
+
+	if (!(mem = pool_create(256))) {
+		log_error("sysfs pool creation failed");
+		return NULL;
+	}
+
+	if (!(ds = _dev_set_create(mem, sys_block))) {
+		log_error("sysfs dev_set creation failed");
+		goto bad;
+	}
+
+	if (!(f = pool_zalloc(mem, sizeof(*f)))) {
+		stack;
+		goto bad;
+	}
+
+	f->passes_filter = _accept_p;
+	f->destroy = _destroy;
+	f->private = ds;
+	return f;
+
+ bad:
+	pool_destroy(mem);
+	return NULL;
+}
+

lib/filters/filter-sysfs.h

@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2004 Red Hat Inc
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LVM_FILTER_SYSFS_H
+#define _LVM_FILTER_SYSFS_H
+
+#include "config.h"
+#include "dev-cache.h"
+
+struct dev_filter *sysfs_filter_create(const char *proc);
+
+#endif