session: add support for saving and restoring session data to disk

diff --git a/include/rpcd/session.h b/include/rpcd/session.h
index 59b2864..70891bc 100644 (file)
--- a/include/rpcd/session.h
+++ b/include/rpcd/session.h
@@ -20,11 +20,19 @@
 #ifndef __RPC_SESSION_H
 #define __RPC_SESSION_H
 
+#include <ctype.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
 #include <libubox/avl.h>
 #include <libubox/blobmsg_json.h>
 
 #define RPC_SID_LEN    32
 #define RPC_DEFAULT_SESSION_TIMEOUT    300
+#define RPC_SESSION_DIRECTORY  "/var/run/rpcd"
 
 struct rpc_session {
        struct avl_node avl;
@@ -68,4 +76,7 @@ struct rpc_session_cb {
 void rpc_session_create_cb(struct rpc_session_cb *cb);
 void rpc_session_destroy_cb(struct rpc_session_cb *cb);
 
+void rpc_session_freeze(void);
+void rpc_session_thaw(void);
+
 #endif

diff --git a/session.c b/session.c
index c8da5a4..e390a9b 100644 (file)
--- a/session.c
+++ b/session.c
@@ -84,6 +84,22 @@ static const struct blobmsg_policy perm_policy[__RPC_SP_MAX] = {
        [RPC_SP_FUNCTION] = { .name = "function", .type = BLOBMSG_TYPE_STRING },
 };
 
+enum {
+       RPC_DUMP_SID,
+       RPC_DUMP_TIMEOUT,
+       RPC_DUMP_EXPIRES,
+       RPC_DUMP_ACLS,
+       RPC_DUMP_DATA,
+       __RPC_DUMP_MAX,
+};
+static const struct blobmsg_policy dump_policy[__RPC_DUMP_MAX] = {
+       [RPC_DUMP_SID] = { .name = "sid", .type = BLOBMSG_TYPE_STRING },
+       [RPC_DUMP_TIMEOUT] = { .name = "timeout", .type = BLOBMSG_TYPE_INT32 },
+       [RPC_DUMP_EXPIRES] = { .name = "expires", .type = BLOBMSG_TYPE_INT32 },
+       [RPC_DUMP_ACLS] = { .name = "acls", .type = BLOBMSG_TYPE_TABLE },
+       [RPC_DUMP_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
+};
+
 /*
  * Keys in the AVL tree contain all pattern characters up to the first wildcard.
  * To look up entries, start with the last entry that has a key less than or
@@ -168,9 +184,7 @@ rpc_session_dump_acls(struct rpc_session *ses, struct blob_buf *b)
 }
 
 static void
-rpc_session_dump(struct rpc_session *ses,
-                                        struct ubus_context *ctx,
-                                        struct ubus_request_data *req)
+rpc_session_to_blob(struct rpc_session *ses)
 {
        void *c;
 
@@ -187,6 +201,13 @@ rpc_session_dump(struct rpc_session *ses,
        c = blobmsg_open_table(&buf, "data");
        rpc_session_dump_data(ses, &buf);
        blobmsg_close_table(&buf, c);
+}
+
+static void
+rpc_session_dump(struct rpc_session *ses, struct ubus_context *ctx,
+                 struct ubus_request_data *req)
+{
+       rpc_session_to_blob(ses);
 
        ubus_send_reply(ctx, req, buf.head);
 }
@@ -234,24 +255,42 @@ static void rpc_session_timeout(struct uloop_timeout *t)
 }
 
 static struct rpc_session *
-rpc_session_create(int timeout)
+rpc_session_new(void)
 {
        struct rpc_session *ses;
-       struct rpc_session_cb *cb;
 
        ses = calloc(1, sizeof(*ses));
+
        if (!ses)
                return NULL;
 
-       ses->timeout  = timeout;
-       ses->avl.key  = ses->id;
-       rpc_random(ses->id);
+       ses->avl.key = ses->id;
 
-       avl_insert(&sessions, &ses->avl);
        avl_init(&ses->acls, avl_strcmp, true, NULL);
        avl_init(&ses->data, avl_strcmp, false, NULL);
 
        ses->t.cb = rpc_session_timeout;
+
+       return ses;
+}
+
+static struct rpc_session *
+rpc_session_create(int timeout)
+{
+       struct rpc_session *ses;
+       struct rpc_session_cb *cb;
+
+       ses = rpc_session_new();
+
+       if (!ses)
+               return NULL;
+
+       rpc_random(ses->id);
+
+       ses->timeout = timeout;
+
+       avl_insert(&sessions, &ses->avl);
+
        rpc_touch_session(ses);
 
        list_for_each_entry(cb, &create_callbacks, list)
@@ -540,13 +579,32 @@ rpc_handle_access(struct ubus_context *ctx, struct ubus_object *obj,
        return 0;
 }
 
+static void
+rpc_session_set(struct rpc_session *ses, const char *key, struct blob_attr *val)
+{
+       struct rpc_session_data *data;
+
+       data = avl_find_element(&ses->data, key, data, avl);
+       if (data) {
+               avl_delete(&ses->data, &data->avl);
+               free(data);
+       }
+
+       data = calloc(1, sizeof(*data) + blob_pad_len(val));
+       if (!data)
+               return;
+
+       memcpy(data->attr, val, blob_pad_len(val));
+       data->avl.key = blobmsg_name(data->attr);
+       avl_insert(&ses->data, &data->avl);
+}
+
 static int
 rpc_handle_set(struct ubus_context *ctx, struct ubus_object *obj,
                struct ubus_request_data *req, const char *method,
                struct blob_attr *msg)
 {
        struct rpc_session *ses;
-       struct rpc_session_data *data;
        struct blob_attr *tb[__RPC_SA_MAX];
        struct blob_attr *attr;
        int rem;
@@ -564,19 +622,7 @@ rpc_handle_set(struct ubus_context *ctx, struct ubus_object *obj,
                if (!blobmsg_name(attr)[0])
                        continue;
 
-               data = avl_find_element(&ses->data, blobmsg_name(attr), data, avl);
-               if (data) {
-                       avl_delete(&ses->data, &data->avl);
-                       free(data);
-               }
-
-               data = calloc(1, sizeof(*data) + blob_pad_len(attr));
-               if (!data)
-                       break;
-
-               memcpy(data->attr, attr, blob_pad_len(attr));
-               data->avl.key = blobmsg_name(data->attr);
-               avl_insert(&ses->data, &data->avl);
+               rpc_session_set(ses, blobmsg_name(attr), attr);
        }
 
        return 0;
@@ -692,6 +738,134 @@ rpc_handle_destroy(struct ubus_context *ctx, struct ubus_object *obj,
        return 0;
 }
 
+
+static bool
+rpc_validate_sid(const char *id)
+{
+       if (!id)
+               return false;
+
+       if (strlen(id) != RPC_SID_LEN)
+               return false;
+
+       while (*id)
+               if (!isxdigit(*id++))
+                       return false;
+
+       return true;
+}
+
+static int
+rpc_blob_to_file(const char *path, struct blob_attr *attr)
+{
+       int fd, len;
+
+       fd = open(path, O_WRONLY | O_CREAT | O_EXCL, 0600);
+
+       if (fd < 0)
+               return fd;
+
+       len = write(fd, attr, blob_pad_len(attr));
+
+       close(fd);
+
+       if (len != blob_pad_len(attr))
+       {
+               unlink(path);
+               return -1;
+       }
+
+       return len;
+}
+
+static struct blob_attr *
+rpc_blob_from_file(const char *path)
+{
+       int fd = -1, len;
+       struct stat s;
+       struct blob_attr head, *attr = NULL;
+
+       if (stat(path, &s) || !S_ISREG(s.st_mode))
+               return NULL;
+
+       fd = open(path, O_RDONLY);
+
+       if (fd < 0)
+               goto fail;
+
+       len = read(fd, &head, sizeof(head));
+
+       if (len != sizeof(head) || blob_pad_len(&head) != s.st_size)
+               goto fail;
+
+       attr = calloc(1, s.st_size);
+
+       if (!attr)
+               goto fail;
+
+       memcpy(attr, &head, sizeof(head));
+
+       len += read(fd, (char *)attr + sizeof(head), s.st_size - sizeof(head));
+
+       if (len != blob_pad_len(&head))
+               goto fail;
+
+       return attr;
+
+fail:
+       if (fd >= 0)
+               close(fd);
+
+       if (attr)
+               free(attr);
+
+       return NULL;
+}
+
+static bool
+rpc_session_from_blob(struct blob_attr *attr)
+{
+       int i, rem, rem2, rem3;
+       struct rpc_session *ses;
+       struct blob_attr *tb[__RPC_DUMP_MAX], *scope, *object, *function;
+
+       blobmsg_parse(dump_policy, __RPC_DUMP_MAX, tb,
+                     blob_data(attr), blob_len(attr));
+
+       for (i = 0; i < __RPC_DUMP_MAX; i++)
+               if (!tb[i])
+                       return false;
+
+       ses = rpc_session_new();
+
+       if (!ses)
+               return false;
+
+       memcpy(ses->id, blobmsg_data(tb[RPC_DUMP_SID]), RPC_SID_LEN);
+
+       ses->timeout = blobmsg_get_u32(tb[RPC_DUMP_TIMEOUT]);
+
+       blobmsg_for_each_attr(scope, tb[RPC_DUMP_ACLS], rem) {
+               blobmsg_for_each_attr(object, scope, rem2) {
+                       blobmsg_for_each_attr(function, object, rem3) {
+                               rpc_session_grant(ses, NULL, blobmsg_name(scope),
+                                                            blobmsg_name(object),
+                                                            blobmsg_data(function));
+                       }
+               }
+       }
+
+       blobmsg_for_each_attr(object, tb[RPC_DUMP_DATA], rem) {
+               rpc_session_set(ses, blobmsg_name(object), object);
+       }
+
+       avl_insert(&sessions, &ses->avl);
+
+       uloop_timeout_set(&ses->t, blobmsg_get_u32(tb[RPC_DUMP_EXPIRES]) * 1000);
+
+       return true;
+}
+
 int rpc_session_api_init(struct ubus_context *ctx)
 {
        static const struct ubus_method session_methods[] = {
@@ -743,3 +917,51 @@ void rpc_session_destroy_cb(struct rpc_session_cb *cb)
        if (cb && cb->cb)
                list_add(&cb->list, &destroy_callbacks);
 }
+
+void rpc_session_freeze(void)
+{
+       struct stat s;
+       struct rpc_session *ses;
+       char path[PATH_MAX];
+
+       if (stat(RPC_SESSION_DIRECTORY, &s))
+               mkdir(RPC_SESSION_DIRECTORY, 0700);
+
+       avl_for_each_element(&sessions, ses, avl) {
+               snprintf(path, sizeof(path) - 1, RPC_SESSION_DIRECTORY "/%s", ses->id);
+               rpc_session_to_blob(ses);
+               rpc_blob_to_file(path, buf.head);
+       }
+}
+
+void rpc_session_thaw(void)
+{
+       DIR *d;
+       char path[PATH_MAX];
+       struct dirent *e;
+       struct blob_attr *attr;
+
+       d = opendir(RPC_SESSION_DIRECTORY);
+
+       if (!d)
+               return;
+
+       while ((e = readdir(d)) != NULL) {
+               if (!rpc_validate_sid(e->d_name))
+                       continue;
+
+               snprintf(path, sizeof(path) - 1,
+                        RPC_SESSION_DIRECTORY "/%s", e->d_name);
+
+               attr = rpc_blob_from_file(path);
+
+               if (attr) {
+                       rpc_session_from_blob(attr);
+                       free(attr);
+               }
+
+               unlink(path);
+       }
+
+       closedir(d);
+}