Create configfs machinery for netconsole userdata appending, which depends
on CONFIG_NETCONSOLE_DYNAMIC (for configfs interface). Add a userdata
config_group to netconsole_target for managing userdata entries as a tree
under the netconsole configfs subsystem. Directory names created under the
userdata directory become userdatum keys; the userdatum value is the
content of the value file.
Include the minimum-viable-changes for userdata configfs config_group.
init_target_config_group() ties in the complete configfs machinery to
avoid unused func/variable errors during build. Initializing the
netconsole_target->group is moved to init_target_config_group, which
will also init and add the userdata config_group.
Each userdatum entry has a limit of 256 bytes (54 for
the key/directory, 200 for the value, and 2 for '=' and '\n'
characters), which is enforced by the configfs functions for updating
the userdata config_group.
When a new netconsole_target is created, initialize the userdata
config_group and add it as a default group for netconsole_target
config_group, allowing the userdata configfs sub-tree to be presented
in the netconsole configfs tree under the userdata directory.
Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
drivers/net/netconsole.c | 147 +++++++++++++++++++++++++++++++++++++--
1 file changed, 142 insertions(+), 5 deletions(-)
@@ -43,6 +43,10 @@ MODULE_DESCRIPTION("Console driver for network interfaces");
MODULE_LICENSE("GPL");
#define MAX_PARAM_LENGTH 256
+#define MAX_USERDATA_NAME_LENGTH 54
+#define MAX_USERDATA_VALUE_LENGTH 200
+#define MAX_USERDATA_ENTRY_LENGTH 256
+#define MAX_USERDATA_ITEMS 16
#define MAX_PRINT_CHUNK 1000
static char config[MAX_PARAM_LENGTH];
@@ -80,6 +84,7 @@ static struct console netconsole_ext;
* struct netconsole_target - Represents a configured netconsole target.
* @list: Links this target into the target_list.
* @group: Links us into the configfs subsystem hierarchy.
+ * @userdata_group: Links to the userdata configfs hierarchy
* @enabled: On / off knob to enable / disable target.
* Visible from userspace (read-write).
* We maintain a strict 1:1 correspondence between this and
@@ -103,6 +108,7 @@ struct netconsole_target {
struct list_head list;
#ifdef CONFIG_NETCONSOLE_DYNAMIC
struct config_group group;
+ struct config_group userdata_group;
#endif
bool enabled;
bool extended;
@@ -215,6 +221,10 @@ static struct netconsole_target *alloc_and_init(void)
* | remote_ip
* | local_mac
* | remote_mac
+ * | userdata/
+ * | <key>/
+ * | value
+ * | ...
* |
* <target>/...
*/
@@ -596,6 +606,123 @@ static ssize_t remote_mac_store(struct config_item *item, const char *buf,
return -EINVAL;
}
+struct userdatum {
+ struct config_item item;
+ char value[MAX_USERDATA_VALUE_LENGTH];
+};
+
+static struct userdatum *to_userdatum(struct config_item *item)
+{
+ return container_of(item, struct userdatum, item);
+}
+
+struct userdata {
+ struct config_group group;
+};
+
+static struct userdata *to_userdata(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct userdata, group);
+}
+
+static struct netconsole_target *userdata_to_target(struct userdata *ud)
+{
+ struct config_group *netconsole_group;
+
+ netconsole_group = to_config_group(ud->group.cg_item.ci_parent);
+ return to_target(&netconsole_group->cg_item);
+}
+
+static ssize_t userdatum_value_show(struct config_item *item, char *buf)
+{
+ return sysfs_emit(buf, "%s\n", &(to_userdatum(item)->value[0]));
+}
+
+static ssize_t userdatum_value_store(struct config_item *item, const char *buf,
+ size_t count)
+{
+ struct userdatum *udm = to_userdatum(item);
+ int ret;
+
+ if (count > MAX_USERDATA_VALUE_LENGTH)
+ return -EMSGSIZE;
+
+ mutex_lock(&dynamic_netconsole_mutex);
+
+ ret = strscpy(udm->value, buf, sizeof(udm->value));
+ if (ret < 0)
+ goto out_unlock;
+ trim_newline(udm->value, sizeof(udm->value));
+
+ mutex_unlock(&dynamic_netconsole_mutex);
+ return count;
+out_unlock:
+ mutex_unlock(&dynamic_netconsole_mutex);
+ return ret;
+}
+
+CONFIGFS_ATTR(userdatum_, value);
+
+static struct configfs_attribute *userdatum_attrs[] = {
+ &userdatum_attr_value,
+ NULL,
+};
+
+static void userdatum_release(struct config_item *item)
+{
+ kfree(to_userdatum(item));
+}
+
+static struct configfs_item_operations userdatum_ops = {
+ .release = userdatum_release,
+};
+
+static const struct config_item_type userdatum_type = {
+ .ct_item_ops = &userdatum_ops,
+ .ct_attrs = userdatum_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_item *userdatum_make_item(struct config_group *group,
+ const char *name)
+{
+ struct netconsole_target *nt;
+ struct userdatum *udm;
+ struct userdata *ud;
+ size_t child_count;
+
+ if (strlen(name) > MAX_USERDATA_NAME_LENGTH)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ ud = to_userdata(&group->cg_item);
+ nt = userdata_to_target(ud);
+ child_count = list_count_nodes(&nt->userdata_group.cg_children);
+ if (child_count >= MAX_USERDATA_ITEMS)
+ return ERR_PTR(-ENOSPC);
+
+ udm = kzalloc(sizeof(*udm), GFP_KERNEL);
+ if (!udm)
+ return ERR_PTR(-ENOMEM);
+
+ config_item_init_type_name(&udm->item, name, &userdatum_type);
+ return &udm->item;
+}
+
+static struct configfs_attribute *userdata_attrs[] = {
+ NULL,
+};
+
+static struct configfs_group_operations userdata_ops = {
+ .make_item = userdatum_make_item,
+};
+
+static struct config_item_type userdata_type = {
+ .ct_item_ops = &userdatum_ops,
+ .ct_group_ops = &userdata_ops,
+ .ct_attrs = userdata_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
CONFIGFS_ATTR(, enabled);
CONFIGFS_ATTR(, extended);
CONFIGFS_ATTR(, dev_name);
@@ -640,6 +767,15 @@ static const struct config_item_type netconsole_target_type = {
.ct_owner = THIS_MODULE,
};
+static void init_target_config_group(struct netconsole_target *nt,
+ const char *name)
+{
+ config_group_init_type_name(&nt->group, name, &netconsole_target_type);
+ config_group_init_type_name(&nt->userdata_group, "userdata",
+ &userdata_type);
+ configfs_add_default_group(&nt->userdata_group, &nt->group);
+}
+
static struct netconsole_target *find_cmdline_target(const char *name)
{
struct netconsole_target *nt, *ret = NULL;
@@ -674,16 +810,18 @@ static struct config_group *make_netconsole_target(struct config_group *group,
if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX,
strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
nt = find_cmdline_target(name);
- if (nt)
+ if (nt) {
+ init_target_config_group(nt, name);
return &nt->group;
+ }
}
nt = alloc_and_init();
if (!nt)
return ERR_PTR(-ENOMEM);
- /* Initialize the config_item member */
- config_group_init_type_name(&nt->group, name, &netconsole_target_type);
+ /* Initialize the config_group member */
+ init_target_config_group(nt, name);
/* Adding, but it is disabled */
spin_lock_irqsave(&target_list_lock, flags);
@@ -740,8 +878,7 @@ static void populate_configfs_item(struct netconsole_target *nt,
snprintf(target_name, sizeof(target_name), "%s%d",
NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
- config_group_init_type_name(&nt->group, target_name,
- &netconsole_target_type);
+ init_target_config_group(nt, target_name);
}
#endif /* CONFIG_NETCONSOLE_DYNAMIC */