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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2/2] xenstore: use temporary memory context for firing watches
Use a temporary memory context for memory allocations when firing
watches. This will avoid leaking memory in case of long living
connections and/or xenstore entries.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
tools/xenstore/xenstored_core.c | 69 ++++++++++++++++++----------------
tools/xenstore/xenstored_core.h | 1 +
tools/xenstore/xenstored_domain.c | 6 +--
tools/xenstore/xenstored_transaction.c | 2 +-
tools/xenstore/xenstored_watch.c | 14 ++++---
tools/xenstore/xenstored_watch.h | 3 +-
6 files changed, 52 insertions(+), 43 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 94c809c..8cb12c7 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -398,7 +398,8 @@ bool is_child(const char *child, const char *parent)
}
/* If it fails, returns NULL and sets errno. */
-static struct node *read_node(struct connection *conn, const char *name)
+static struct node *read_node(struct connection *conn, const void *mem,
+ const char *name)
{
TDB_DATA key, data;
uint32_t *p;
@@ -419,7 +420,7 @@ static struct node *read_node(struct connection *conn,
const char *name)
return NULL;
}
- node = talloc(name, struct node);
+ node = talloc(mem, struct node);
node->name = talloc_strdup(node, name);
node->parent = NULL;
node->tdb = tdb_context(conn);
@@ -507,22 +508,23 @@ static enum xs_perm_type perm_for_conn(struct connection
*conn,
return perms[0].perms & mask;
}
-static char *get_parent(const char *node)
+static char *get_parent(const void *mem, const char *node)
{
char *slash = strrchr(node + 1, '/');
if (!slash)
- return talloc_strdup(node, "/");
- return talloc_asprintf(node, "%.*s", (int)(slash - node), node);
+ return talloc_strdup(mem, "/");
+ return talloc_asprintf(mem, "%.*s", (int)(slash - node), node);
}
/* What do parents say? */
-static enum xs_perm_type ask_parents(struct connection *conn, const char *name)
+static enum xs_perm_type ask_parents(struct connection *conn, const void *mem,
+ const char *name)
{
struct node *node;
do {
- name = get_parent(name);
- node = read_node(conn, name);
+ name = get_parent(mem, name);
+ node = read_node(conn, mem, name);
if (node)
break;
} while (!streq(name, "/"));
@@ -540,20 +542,22 @@ static enum xs_perm_type ask_parents(struct connection
*conn, const char *name)
* specific node without allowing it in the parents. If it's going to
* fail, however, we don't want the errno to indicate any information
* about the node. */
-static int errno_from_parents(struct connection *conn, const char *node,
- int errnum, enum xs_perm_type perm)
+static int errno_from_parents(struct connection *conn, const void *mem,
+ const char *node, int errnum,
+ enum xs_perm_type perm)
{
/* We always tell them about memory failures. */
if (errnum == ENOMEM)
return errnum;
- if (ask_parents(conn, node) & perm)
+ if (ask_parents(conn, mem, node) & perm)
return errnum;
return EACCES;
}
/* If it fails, returns NULL and sets errno. */
struct node *get_node(struct connection *conn,
+ const void *mem,
const char *name,
enum xs_perm_type perm)
{
@@ -563,7 +567,7 @@ struct node *get_node(struct connection *conn,
errno = EINVAL;
return NULL;
}
- node = read_node(conn, name);
+ node = read_node(conn, mem, name);
/* If we don't have permission, we don't have node. */
if (node) {
if ((perm_for_conn(conn, node->perms, node->num_perms) & perm)
@@ -574,7 +578,7 @@ struct node *get_node(struct connection *conn,
}
/* Clean up errno if they weren't supposed to know. */
if (!node)
- errno = errno_from_parents(conn, name, errno, perm);
+ errno = errno_from_parents(conn, mem, name, errno, perm);
return node;
}
@@ -767,7 +771,7 @@ static void send_directory(struct connection *conn, struct
buffered_data *in)
const char *name = onearg(in);
name = canonicalize(conn, name);
- node = get_node(conn, name, XS_PERM_READ);
+ node = get_node(conn, in, name, XS_PERM_READ);
if (!node) {
send_error(conn, errno);
return;
@@ -782,7 +786,7 @@ static void do_read(struct connection *conn, struct
buffered_data *in)
const char *name = onearg(in);
name = canonicalize(conn, name);
- node = get_node(conn, name, XS_PERM_READ);
+ node = get_node(conn, in, name, XS_PERM_READ);
if (!node) {
send_error(conn, errno);
return;
@@ -816,10 +820,10 @@ static struct node *construct_node(struct connection
*conn, const char *name)
const char *base;
unsigned int baselen;
struct node *parent, *node;
- char *children, *parentname = get_parent(name);
+ char *children, *parentname = get_parent(name, name);
/* If parent doesn't exist, create it. */
- parent = read_node(conn, parentname);
+ parent = read_node(conn, parentname, parentname);
if (!parent)
parent = construct_node(conn, parentname);
if (!parent)
@@ -919,7 +923,7 @@ static void do_write(struct connection *conn, struct
buffered_data *in)
datalen = in->used - offset;
name = canonicalize(conn, vec[0]);
- node = get_node(conn, name, XS_PERM_WRITE);
+ node = get_node(conn, in, name, XS_PERM_WRITE);
if (!node) {
/* No permissions, invalid input? */
if (errno != ENOENT) {
@@ -941,7 +945,7 @@ static void do_write(struct connection *conn, struct
buffered_data *in)
}
add_change_node(conn->transaction, name, false);
- fire_watches(conn, name, false);
+ fire_watches(conn, in, name, false);
send_ack(conn, XS_WRITE);
}
@@ -951,7 +955,7 @@ static void do_mkdir(struct connection *conn, struct
buffered_data *in)
const char *name = onearg(in);
name = canonicalize(conn, name);
- node = get_node(conn, name, XS_PERM_WRITE);
+ node = get_node(conn, in, name, XS_PERM_WRITE);
/* If it already exists, fine. */
if (!node) {
@@ -966,7 +970,7 @@ static void do_mkdir(struct connection *conn, struct
buffered_data *in)
return;
}
add_change_node(conn->transaction, name, false);
- fire_watches(conn, name, false);
+ fire_watches(conn, in, name, false);
}
send_ack(conn, XS_MKDIR);
}
@@ -984,7 +988,7 @@ static void delete_node(struct connection *conn, struct
node *node)
for (i = 0; i < node->childlen; i += strlen(node->children+i) + 1) {
struct node *child;
- child = read_node(conn,
+ child = read_node(conn, node,
talloc_asprintf(node, "%s/%s", node->name,
node->children + i));
if (child) {
@@ -1036,7 +1040,7 @@ static int _rm(struct connection *conn, struct node
*node, const char *name)
/* Delete from parent first, then if we crash, the worst that can
happen is the child will continue to take up space, but will
otherwise be unreachable. */
- struct node *parent = read_node(conn, get_parent(name));
+ struct node *parent = read_node(conn, name, get_parent(name, name));
if (!parent) {
send_error(conn, EINVAL);
return 0;
@@ -1055,7 +1059,7 @@ static int _rm(struct connection *conn, struct node
*node, const char *name)
static void internal_rm(const char *name)
{
char *tname = talloc_strdup(NULL, name);
- struct node *node = read_node(NULL, tname);
+ struct node *node = read_node(NULL, tname, tname);
if (node)
_rm(NULL, node, tname);
talloc_free(node);
@@ -1069,11 +1073,11 @@ static void do_rm(struct connection *conn, struct
buffered_data *in)
const char *name = onearg(in);
name = canonicalize(conn, name);
- node = get_node(conn, name, XS_PERM_WRITE);
+ node = get_node(conn, in, name, XS_PERM_WRITE);
if (!node) {
/* Didn't exist already? Fine, if parent exists. */
if (errno == ENOENT) {
- node = read_node(conn, get_parent(name));
+ node = read_node(conn, in, get_parent(in, name));
if (node) {
send_ack(conn, XS_RM);
return;
@@ -1092,7 +1096,7 @@ static void do_rm(struct connection *conn, struct
buffered_data *in)
if (_rm(conn, node, name)) {
add_change_node(conn->transaction, name, true);
- fire_watches(conn, name, true);
+ fire_watches(conn, in, name, true);
send_ack(conn, XS_RM);
}
}
@@ -1106,7 +1110,7 @@ static void do_get_perms(struct connection *conn, struct
buffered_data *in)
unsigned int len;
name = canonicalize(conn, name);
- node = get_node(conn, name, XS_PERM_READ);
+ node = get_node(conn, in, name, XS_PERM_READ);
if (!node) {
send_error(conn, errno);
return;
@@ -1138,7 +1142,7 @@ static void do_set_perms(struct connection *conn, struct
buffered_data *in)
num--;
/* We must own node to do this (tools can do this too). */
- node = get_node(conn, name, XS_PERM_WRITE|XS_PERM_OWNER);
+ node = get_node(conn, in, name, XS_PERM_WRITE|XS_PERM_OWNER);
if (!node) {
send_error(conn, errno);
return;
@@ -1168,7 +1172,7 @@ static void do_set_perms(struct connection *conn, struct
buffered_data *in)
}
add_change_node(conn->transaction, name, false);
- fire_watches(conn, name, false);
+ fire_watches(conn, in, name, false);
send_ack(conn, XS_SET_PERMS);
}
@@ -1604,7 +1608,7 @@ static void remember_string(struct hashtable *hash, const
char *str)
*/
static void check_store_(const char *name, struct hashtable *reachable)
{
- struct node *node = read_node(NULL, name);
+ struct node *node = read_node(NULL, name, name);
if (node) {
size_t i = 0;
@@ -1618,7 +1622,8 @@ static void check_store_(const char *name, struct
hashtable *reachable)
size_t childlen = strlen(node->children + i);
char * childname = child_name(node->name,
node->children + i);
- struct node *childnode = read_node(NULL, childname);
+ struct node *childnode = read_node(NULL, childname,
+ childname);
if (childnode) {
if (hashtable_search(children, childname)) {
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 5dbf9c8..f763e47 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -149,6 +149,7 @@ bool check_event_node(const char *node);
/* Get this node, checking we have permissions. */
struct node *get_node(struct connection *conn,
+ const void *mem,
const char *name,
enum xs_perm_type perm);
diff --git a/tools/xenstore/xenstored_domain.c
b/tools/xenstore/xenstored_domain.c
index c66539a..5de93d4 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -204,7 +204,7 @@ static int destroy_domain(void *_domain)
unmap_interface(domain->interface);
}
- fire_watches(NULL, "@releaseDomain", false);
+ fire_watches(NULL, domain, "@releaseDomain", false);
return 0;
}
@@ -232,7 +232,7 @@ static void domain_cleanup(void)
}
if (notify)
- fire_watches(NULL, "@releaseDomain", false);
+ fire_watches(NULL, NULL, "@releaseDomain", false);
}
/* We scan all domains rather than use the information given here. */
@@ -389,7 +389,7 @@ void do_introduce(struct connection *conn, struct
buffered_data *in)
/* Now domain belongs to its connection. */
talloc_steal(domain->conn, domain);
- fire_watches(NULL, "@introduceDomain", false);
+ fire_watches(NULL, in, "@introduceDomain", false);
} else if ((domain->mfn == mfn) && (domain->conn != conn)) {
/* Use XS_INTRODUCE for recreating the xenbus event-channel. */
if (domain->port)
diff --git a/tools/xenstore/xenstored_transaction.c
b/tools/xenstore/xenstored_transaction.c
index 3cde26e..34720fa 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -227,7 +227,7 @@ void do_transaction_end(struct connection *conn, struct
buffered_data *in)
/* Fire off the watches for everything that changed. */
list_for_each_entry(i, &trans->changes, list)
- fire_watches(conn, i->node, i->recurse);
+ fire_watches(conn, in, i->node, i->recurse);
generation++;
}
send_ack(conn, XS_TRANSACTION_END);
diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c
index 8543999..8149701 100644
--- a/tools/xenstore/xenstored_watch.c
+++ b/tools/xenstore/xenstored_watch.c
@@ -48,6 +48,7 @@ struct watch
};
static void add_event(struct connection *conn,
+ void *tmp,
struct watch *watch,
const char *name)
{
@@ -57,7 +58,7 @@ static void add_event(struct connection *conn,
if (!check_event_node(name)) {
/* Can this conn load node, or see that it doesn't exist? */
- struct node *node = get_node(conn, name, XS_PERM_READ);
+ struct node *node = get_node(conn, tmp, name, XS_PERM_READ);
/*
* XXX We allow EACCES here because otherwise a non-dom0
* backend driver cannot watch for disappearance of a frontend
@@ -78,14 +79,15 @@ static void add_event(struct connection *conn,
}
len = strlen(name) + 1 + strlen(watch->token) + 1;
- data = talloc_array(watch, char, len);
+ data = talloc_array(tmp, char, len);
strcpy(data, name);
strcpy(data + strlen(name) + 1, watch->token);
send_reply(conn, XS_WATCH_EVENT, data, len);
talloc_free(data);
}
-void fire_watches(struct connection *conn, const char *name, bool recurse)
+void fire_watches(struct connection *conn, void *tmp, const char *name,
+ bool recurse)
{
struct connection *i;
struct watch *watch;
@@ -98,9 +100,9 @@ void fire_watches(struct connection *conn, const char *name,
bool recurse)
list_for_each_entry(i, &connections, list) {
list_for_each_entry(watch, &i->watches, list) {
if (is_child(name, watch->node))
- add_event(i, watch, name);
+ add_event(i, tmp, watch, name);
else if (recurse && is_child(watch->node, name))
- add_event(i, watch, watch->node);
+ add_event(i, tmp, watch, watch->node);
}
}
}
@@ -169,7 +171,7 @@ void do_watch(struct connection *conn, struct buffered_data
*in)
send_ack(conn, XS_WATCH);
/* We fire once up front: simplifies clients and restart. */
- add_event(conn, watch, watch->node);
+ add_event(conn, in, watch, watch->node);
}
void do_unwatch(struct connection *conn, struct buffered_data *in)
diff --git a/tools/xenstore/xenstored_watch.h b/tools/xenstore/xenstored_watch.h
index 5bc4f88..8ed1dde 100644
--- a/tools/xenstore/xenstored_watch.h
+++ b/tools/xenstore/xenstored_watch.h
@@ -25,7 +25,8 @@ void do_watch(struct connection *conn, struct buffered_data
*in);
void do_unwatch(struct connection *conn, struct buffered_data *in);
/* Fire all watches: recurse means all the children are affected (ie. rm). */
-void fire_watches(struct connection *conn, const char *name, bool recurse);
+void fire_watches(struct connection *conn, void *tmp, const char *name,
+ bool recurse);
void dump_watches(struct connection *conn);
--
2.6.6
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