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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Added further integrity checking, this time checking for duplicate directory
# HG changeset patch
# User emellor@xxxxxxxxxxxxxxxxxxxxxx
# Node ID f68f6f711efc1774b96eee63839eaf0fc6ccd3dd
# Parent bac71019f6aacc8393eddfb7f28a3972d253ea50
Added further integrity checking, this time checking for duplicate directory
entries and for orphaned nodes in the database.
Added two flags, -R and -L, to disable the recovery code and the remove of
/local at start-up. This makes it much easier to analyse corrupted tdb files.
Added some missing talloc_free calls in the previous integrity checking code.
Removed the transaction handle from the trace_io message -- unfortunately,
the transaction is always null at this point, as it's not yet been looked up.
Signed-off-by: Ewan Mellor <ewan@xxxxxxxxxxxxx>
diff -r bac71019f6aa -r f68f6f711efc tools/xenstore/Makefile
--- a/tools/xenstore/Makefile Wed Mar 8 22:57:34 2006
+++ b/tools/xenstore/Makefile Wed Mar 8 22:57:40 2006
@@ -34,7 +34,7 @@
testcode: xs_test xenstored_test xs_random
-xenstored: xenstored_core.o xenstored_watch.o xenstored_domain.o
xenstored_transaction.o xs_lib.o talloc.o utils.o tdb.o
+xenstored: xenstored_core.o xenstored_watch.o xenstored_domain.o
xenstored_transaction.o xs_lib.o talloc.o utils.o tdb.o hashtable.o
$(LINK.o) $^ $(LOADLIBES) $(LDLIBS) -lxenctrl -o $@
$(CLIENTS): xenstore-%: xenstore_%.o libxenstore.so
diff -r bac71019f6aa -r f68f6f711efc tools/xenstore/xenstored_core.c
--- a/tools/xenstore/xenstored_core.c Wed Mar 8 22:57:34 2006
+++ b/tools/xenstore/xenstored_core.c Wed Mar 8 22:57:40 2006
@@ -51,11 +51,16 @@
#include "xenctrl.h"
#include "tdb.h"
+#include "hashtable.h"
+
+
extern int eventchn_fd; /* in xenstored_domain.c */
-static bool verbose;
+static bool verbose = false;
LIST_HEAD(connections);
static int tracefd = -1;
+static bool recovery = true;
+static bool remove_local = true;
static int reopen_log_pipe[2];
static char *tracefile = NULL;
static TDB_CONTEXT *tdb_ctx;
@@ -201,8 +206,8 @@
now = time(NULL);
tm = localtime(&now);
- trace("%s %p %p %04d%02d%02d %02d:%02d:%02d %s (", prefix, conn,
- conn->transaction, tm->tm_year + 1900, tm->tm_mon + 1,
+ trace("%s %p %04d%02d%02d %02d:%02d:%02d %s (", prefix, conn,
+ tm->tm_year + 1900, tm->tm_mon + 1,
tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec,
sockmsg_string(data->hdr.msg.type));
@@ -947,12 +952,24 @@
}
}
+
/* Delete memory using memmove. */
static void memdel(void *mem, unsigned off, unsigned len, unsigned total)
{
memmove(mem + off, mem + off + len, total - off - len);
}
+
+static bool remove_child_entry(struct connection *conn, struct node *node,
+ size_t offset)
+{
+ size_t childlen = strlen(node->children + offset);
+ memdel(node->children, offset, childlen + 1, node->childlen);
+ node->childlen -= childlen + 1;
+ return write_node(conn, node);
+}
+
+
static bool delete_child(struct connection *conn,
struct node *node, const char *childname)
{
@@ -960,10 +977,7 @@
for (i = 0; i < node->childlen; i += strlen(node->children+i) + 1) {
if (streq(node->children+i, childname)) {
- memdel(node->children, i, strlen(childname) + 1,
- node->childlen);
- node->childlen -= strlen(childname) + 1;
- return write_node(conn, node);
+ return remove_child_entry(conn, node, i);
}
}
corrupt(conn, "Can't find child '%s' in %s", childname, node->name);
@@ -998,6 +1012,7 @@
struct node *node = read_node(NULL, tname);
if (node)
_rm(NULL, node, tname);
+ talloc_free(node);
talloc_free(tname);
}
@@ -1429,12 +1444,14 @@
check_store();
- internal_rm("/local");
- create_node(NULL, tlocal, NULL, 0);
+ if (remove_local) {
+ internal_rm("/local");
+ create_node(NULL, tlocal, NULL, 0);
+
+ check_store();
+ }
talloc_free(tlocal);
-
- check_store();
}
else {
tdb_ctx = tdb_open(tdbname, 7919, TDB_FLAGS, O_RDWR|O_CREAT,
@@ -1450,6 +1467,26 @@
}
}
+
+static unsigned int hash_from_key_fn(void *k)
+{
+ char *str = k;
+ unsigned int hash = 5381;
+ char c;
+
+ while ((c = *str++))
+ hash = ((hash << 5) + hash) + (unsigned int)c;
+
+ return hash;
+}
+
+
+static int keys_equal_fn(void *key1, void *key2)
+{
+ return 0 == strcmp((char *)key1, (char *)key2);
+}
+
+
static char *child_name(const char *s1, const char *s2)
{
if (strcmp(s1, "/")) {
@@ -1460,12 +1497,39 @@
}
}
-static void check_store_(const char *name)
+
+static void remember_string(struct hashtable *hash, const char *str)
+{
+ char *k = malloc(strlen(str) + 1);
+ strcpy(k, str);
+ hashtable_insert(hash, k, (void *)1);
+}
+
+
+/**
+ * A node has a children field that names the children of the node, separated
+ * by NULs. We check whether there are entries in there that are duplicated
+ * (and if so, delete the second one), and whether there are any that do not
+ * have a corresponding child node (and if so, delete them). Each valid child
+ * is then recursively checked.
+ *
+ * No deleting is performed if the recovery flag is cleared (i.e. -R was
+ * passed on the command line).
+ *
+ * As we go, we record each node in the given reachable hashtable. These
+ * entries will be used later in clean_store.
+ */
+static void check_store_(const char *name, struct hashtable *reachable)
{
struct node *node = read_node(NULL, name);
if (node) {
size_t i = 0;
+
+ struct hashtable * children =
+ create_hashtable(16, hash_from_key_fn, keys_equal_fn);
+
+ remember_string(reachable, name);
while (i < node->childlen) {
size_t childlen = strlen(node->children + i);
@@ -1474,21 +1538,39 @@
struct node *childnode = read_node(NULL, childname);
if (childnode) {
- check_store_(childname);
- i += childlen + 1;
+ if (hashtable_search(children, childname)) {
+ log("check_store: '%s' is duplicated!",
+ childname);
+
+ if (recovery) {
+ remove_child_entry(NULL, node,
+ i);
+ i -= childlen + 1;
+ }
+ }
+ else {
+ remember_string(children, childname);
+ check_store_(childname, reachable);
+ }
}
else {
log("check_store: No child '%s' found!\n",
childname);
- memdel(node->children, i, childlen + 1,
- node->childlen);
- node->childlen -= childlen + 1;
- write_node(NULL, node);
+ if (recovery) {
+ remove_child_entry(NULL, node, i);
+ i -= childlen + 1;
+ }
}
+ talloc_free(childnode);
talloc_free(childname);
+ i += childlen + 1;
}
+
+ hashtable_destroy(children, 0 /* Don't free values (they are
+ all (void *)1) */);
+ talloc_free(node);
}
else {
/* Impossible, because no database should ever be without the
@@ -1500,12 +1582,51 @@
}
+/**
+ * Helper to clean_store below.
+ */
+static int clean_store_(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA val,
+ void *private)
+{
+ struct hashtable *reachable = private;
+ char * name = talloc_strndup(NULL, key.dptr, key.dsize);
+
+ if (!hashtable_search(reachable, name)) {
+ log("clean_store: '%s' is orphaned!", name);
+ if (recovery) {
+ tdb_delete(tdb, key);
+ }
+ }
+
+ talloc_free(name);
+
+ return 0;
+}
+
+
+/**
+ * Given the list of reachable nodes, iterate over the whole store, and
+ * remove any that were not reached.
+ */
+static void clean_store(struct hashtable *reachable)
+{
+ tdb_traverse(tdb_ctx, &clean_store_, reachable);
+}
+
+
static void check_store()
{
char * root = talloc_strdup(NULL, "/");
+ struct hashtable * reachable =
+ create_hashtable(16, hash_from_key_fn, keys_equal_fn);
+
log("Checking store ...");
- check_store_(root);
+ check_store_(root, reachable);
+ clean_store(reachable);
log("Checking store complete.");
+
+ hashtable_destroy(reachable, 0 /* Don't free values (they are all
+ (void *)1) */);
talloc_free(root);
}
@@ -1594,6 +1715,9 @@
" --no-fork to request that the daemon does not fork,\n"
" --output-pid to request that the pid of the daemon is output,\n"
" --trace-file <file> giving the file for logging, and\n"
+" --no-recovery to request that no recovery should be attempted when\n"
+" the store is corrupted (debug only),\n"
+" --preserve-local to request that /local is preserved on start-up,\n"
" --verbose to request verbose execution.\n");
}
@@ -1605,6 +1729,8 @@
{ "no-fork", 0, NULL, 'N' },
{ "output-pid", 0, NULL, 'P' },
{ "trace-file", 1, NULL, 'T' },
+ { "no-recovery", 0, NULL, 'R' },
+ { "preserve-local", 0, NULL, 'L' },
{ "verbose", 0, NULL, 'V' },
{ NULL, 0, NULL, 0 } };
@@ -1620,7 +1746,7 @@
bool no_domain_init = false;
const char *pidfile = NULL;
- while ((opt = getopt_long(argc, argv, "DF:HNPT:V", options,
+ while ((opt = getopt_long(argc, argv, "DF:HNPT:RLV", options,
NULL)) != -1) {
switch (opt) {
case 'D':
@@ -1638,6 +1764,12 @@
case 'P':
outputpid = true;
break;
+ case 'R':
+ recovery = false;
+ break;
+ case 'L':
+ remove_local = false;
+ break;
case 'T':
tracefile = optarg;
break;
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