Messages in this thread Patch in this message | | | From | Matthew Wood <> | Subject | [PATCH net-next v1 5/8] net: netconsole: add a userdata config_group member to netconsole_target | Date | Wed, 24 Jan 2024 09:47:03 -0800 |
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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 | 142 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 138 insertions(+), 4 deletions(-)
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 586945e62210..26a3bb070ad0 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -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]; @@ -103,6 +107,7 @@ 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 +220,10 @@ static struct netconsole_target *alloc_and_init(void) * | remote_ip * | local_mac * | remote_mac + * | userdata/ + * | <key>/ + * | value + * | ... * | * <target>/... */ @@ -596,6 +605,123 @@ 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 inline struct userdatum *to_userdatum(struct config_item *item) +{ + return container_of(item, struct userdatum, item); +} + +struct userdata { + struct config_group group; +}; + +static inline 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 +766,14 @@ 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; @@ -675,6 +809,7 @@ static struct config_group *make_netconsole_target(struct config_group *group, strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) { nt = find_cmdline_target(name); if (nt) { + init_target_config_group(nt, name); return &nt->group; } } @@ -683,8 +818,8 @@ static struct config_group *make_netconsole_target(struct config_group *group, 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); @@ -741,8 +876,7 @@ 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 */ -- 2.43.0
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