[PATCH v6 12/14] tools/xenstore: use generic accounting for remaining quotas

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>, Wei Liu <wl@xen.org>,
	Julien Grall <julien@xen.org>,
	Anthony PERARD <anthony.perard@citrix.com>
Subject: [PATCH v6 12/14] tools/xenstore: use generic accounting for remaining quotas
Date: Tue, 30 May 2023 10:24:22 +0200	[thread overview]
Message-ID: <20230530082424.32126-13-jgross@suse.com> (raw)
In-Reply-To: <20230530082424.32126-1-jgross@suse.com>

The maxrequests, node size, number of node permissions, and path length
quota are a little bit special, as they are either active in
transactions only (maxrequests), or they are just per item instead of
count values. Nevertheless being able to know the maximum number of
those quota related values per domain would be beneficial, so add them
to the generic accounting.

The per domain value will never show current numbers other than zero,
but the maximum number seen can be gathered the same way as the number
of nodes during a transaction.

To be able to use the const qualifier for a new function switch
domain_is_unprivileged() to take a const pointer, too.

For printing the quota/max values, adapt the print format string to
the longest quota name (now 17 characters long).

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V5:
- add comment (Julien Grall)
- add missing quota printing (Julien Grall)
V6:
- keep assert() (Julien Grall)
---
 tools/xenstore/xenstored_core.c        | 15 ++++-----
 tools/xenstore/xenstored_core.h        |  2 +-
 tools/xenstore/xenstored_domain.c      | 43 ++++++++++++++++++++++----
 tools/xenstore/xenstored_domain.h      |  6 ++++
 tools/xenstore/xenstored_transaction.c |  4 +--
 tools/xenstore/xenstored_watch.c       |  2 +-
 6 files changed, 55 insertions(+), 17 deletions(-)

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 3343f939b4..dd00f74cb6 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -799,8 +799,9 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node,
 		+ node->perms.num * sizeof(node->perms.p[0])
 		+ node->datalen + node->childlen;
 
-	if (!no_quota_check && domain_is_unprivileged(conn) &&
-	    data.dsize >= quota_max_entry_size) {
+	/* Call domain_max_chk() in any case in order to record max values. */
+	if (domain_max_chk(conn, ACC_NODESZ, data.dsize, quota_max_entry_size)
+	    && !no_quota_check) {
 		errno = ENOSPC;
 		return errno;
 	}
@@ -1170,7 +1171,7 @@ static bool valid_chars(const char *node)
 		       "0123456789-/_@") == strlen(node));
 }
 
-bool is_valid_nodename(const char *node)
+bool is_valid_nodename(const struct connection *conn, const char *node)
 {
 	int local_off = 0;
 	unsigned int domid;
@@ -1190,7 +1191,8 @@ bool is_valid_nodename(const char *node)
 	if (sscanf(node, "/local/domain/%5u/%n", &domid, &local_off) != 1)
 		local_off = 0;
 
-	if (strlen(node) > local_off + quota_max_path_len)
+	if (domain_max_chk(conn, ACC_PATHLEN, strlen(node) - local_off,
+			   quota_max_path_len))
 		return false;
 
 	return valid_chars(node);
@@ -1252,7 +1254,7 @@ static struct node *get_node_canonicalized(struct connection *conn,
 	*canonical_name = canonicalize(conn, ctx, name);
 	if (!*canonical_name)
 		return NULL;
-	if (!is_valid_nodename(*canonical_name)) {
+	if (!is_valid_nodename(conn, *canonical_name)) {
 		errno = EINVAL;
 		return NULL;
 	}
@@ -1784,8 +1786,7 @@ static int do_set_perms(const void *ctx, struct connection *conn,
 		return EINVAL;
 
 	perms.num--;
-	if (domain_is_unprivileged(conn) &&
-	    perms.num > quota_nb_perms_per_node)
+	if (domain_max_chk(conn, ACC_NPERM, perms.num, quota_nb_perms_per_node))
 		return ENOSPC;
 
 	permstr = in->buffer + strlen(in->buffer) + 1;
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 3564d85d7d..9339820156 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -258,7 +258,7 @@ void check_store(void);
 void corrupt(struct connection *conn, const char *fmt, ...);
 
 /* Is this a valid node name? */
-bool is_valid_nodename(const char *node);
+bool is_valid_nodename(const struct connection *conn, const char *node);
 
 /* Get name of parent node. */
 char *get_parent(const void *ctx, const char *node);
diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index 6f3a27765a..57a573e5dd 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -431,7 +431,7 @@ int domain_get_quota(const void *ctx, struct connection *conn,
 		return ENOMEM;
 
 #define ent(t, e) \
-	resp = talloc_asprintf_append(resp, "%-16s: %8u (max: %8u\n", #t, \
+	resp = talloc_asprintf_append(resp, "%-17s: %8u (max: %8u\n", #t, \
 				      d->acc[e].val, d->acc[e].max); \
 	if (!resp) return ENOMEM
 
@@ -440,6 +440,10 @@ int domain_get_quota(const void *ctx, struct connection *conn,
 	ent(transactions, ACC_TRANS);
 	ent(outstanding, ACC_OUTST);
 	ent(memory, ACC_MEM);
+	ent(transaction-nodes, ACC_TRANSNODES);
+	ent(node-permissions, ACC_NPERM);
+	ent(path-length, ACC_PATHLEN);
+	ent(node-size, ACC_NODESZ);
 
 #undef ent
 
@@ -457,7 +461,7 @@ int domain_max_global_acc(const void *ctx, struct connection *conn)
 		return ENOMEM;
 
 #define ent(t, e) \
-	resp = talloc_asprintf_append(resp, "%-16s: %8u\n", #t,   \
+	resp = talloc_asprintf_append(resp, "%-17s: %8u\n", #t,   \
 				      acc_global_max[e]);         \
 	if (!resp) return ENOMEM
 
@@ -466,6 +470,10 @@ int domain_max_global_acc(const void *ctx, struct connection *conn)
 	ent(transactions, ACC_TRANS);
 	ent(outstanding, ACC_OUTST);
 	ent(memory, ACC_MEM);
+	ent(transaction-nodes, ACC_TRANSNODES);
+	ent(node-permissions, ACC_NPERM);
+	ent(path-length, ACC_PATHLEN);
+	ent(node-size, ACC_NODESZ);
 
 #undef ent
 
@@ -1079,6 +1087,18 @@ int domain_adjust_node_perms(struct node *node)
 	return 0;
 }
 
+static void domain_acc_valid_max(struct domain *d, enum accitem what,
+				 unsigned int val)
+{
+	assert(what < ARRAY_SIZE(d->acc));
+	assert(what < ARRAY_SIZE(acc_global_max));
+
+	if (val > d->acc[what].max)
+		d->acc[what].max = val;
+	if (val > acc_global_max[what] && domid_is_unprivileged(d->domid))
+		acc_global_max[what] = val;
+}
+
 static int domain_acc_add_valid(struct domain *d, enum accitem what, int add)
 {
 	unsigned int val;
@@ -1098,10 +1118,7 @@ static int domain_acc_add_valid(struct domain *d, enum accitem what, int add)
 	}
 
 	val = d->acc[what].val + add;
-	if (val > d->acc[what].max)
-		d->acc[what].max = val;
-	if (val > acc_global_max[what] && domid_is_unprivileged(d->domid))
-		acc_global_max[what] = val;
+	domain_acc_valid_max(d, what, val);
 
 	return val;
 }
@@ -1222,6 +1239,20 @@ void domain_reset_global_acc(void)
 	hashtable_iterate(domhash, domain_reset_global_acc_sub, NULL);
 }
 
+bool domain_max_chk(const struct connection *conn, enum accitem what,
+		    unsigned int val, unsigned int quota)
+{
+	if (!conn || !conn->domain)
+		return false;
+
+	if (domain_is_unprivileged(conn) && val > quota)
+		return true;
+
+	domain_acc_valid_max(conn->domain, what, val);
+
+	return false;
+}
+
 int domain_nbentry_inc(struct connection *conn, unsigned int domid)
 {
 	return (domain_acc_add(conn, domid, ACC_NODES, 1, false) < 0)
diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
index 416df25cb2..78ca434531 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -33,6 +33,10 @@ enum accitem {
 	ACC_OUTST,
 	ACC_MEM,
 	ACC_TRANS,
+	ACC_TRANSNODES,
+	ACC_NPERM,
+	ACC_PATHLEN,
+	ACC_NODESZ,
 	ACC_N,			/* Number of elements per domain. */
 };
 
@@ -129,6 +133,8 @@ void acc_drop(struct connection *conn);
 void acc_commit(struct connection *conn);
 int domain_max_global_acc(const void *ctx, struct connection *conn);
 void domain_reset_global_acc(void);
+bool domain_max_chk(const struct connection *conn, unsigned int what,
+		    unsigned int val, unsigned int quota);
 
 /* Write rate limiting */
 
diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index 9cfb0017c8..580d7bd090 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -252,8 +252,8 @@ int access_node(struct connection *conn, struct node *node,
 
 	i = find_accessed_node(trans, node->name);
 	if (!i) {
-		if (trans->nodes >= quota_trans_nodes &&
-		    domain_is_unprivileged(conn)) {
+		if (domain_max_chk(conn, ACC_TRANSNODES, trans->nodes + 1,
+				   quota_trans_nodes)) {
 			ret = ENOSPC;
 			goto err;
 		}
diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c
index e30cd89be3..61b1e3421e 100644
--- a/tools/xenstore/xenstored_watch.c
+++ b/tools/xenstore/xenstored_watch.c
@@ -176,7 +176,7 @@ static int check_watch_path(struct connection *conn, const void *ctx,
 		*path = canonicalize(conn, ctx, *path);
 		if (!*path)
 			return errno;
-		if (!is_valid_nodename(*path))
+		if (!is_valid_nodename(conn, *path))
 			goto inval;
 	}
 
-- 
2.35.3


