lib: Add function to get children of node in RIB

Returns the names of the nodes (not the full paths). The function
allocates memory to the children pointer that should be freed.

3 files changed, 94 insertions, 0 deletions

diff --git a/include/ouroboros/rib.h b/include/ouroboros/rib.h
index 5acf0330..1d0661a7 100644
--- a/include/ouroboros/rib.h
+++ b/include/ouroboros/rib.h
@@ -52,6 +52,9 @@ int     rib_put(const char * path,
 
 bool    rib_has(const char * path);
 
+ssize_t rib_children(const char * path,
+                     char ***     children);
+
 char *  rib_path_append(char *       path,
                         const char * name);
 
diff --git a/src/lib/rib.c b/src/lib/rib.c
index 4d1ae884..6b27ad27 100644
--- a/src/lib/rib.c
+++ b/src/lib/rib.c
@@ -95,6 +95,7 @@ struct rnode {
 
         struct rnode *   parent;
 
+        size_t           chlen;
         struct list_head children;
 
         struct list_head subs;
@@ -248,6 +249,8 @@ static int rnode_add_child(struct rnode * node,
         c->node = child;
         list_add(&c->next, &node->children);
 
+        ++node->chlen;
+
         return 0;
 }
 
@@ -265,6 +268,7 @@ static void rnode_remove_child(struct rnode * node,
                 if (c->node == child) {
                         list_del(&c->next);
                         free(c);
+                        --node->chlen;
                         return;
                 }
         }
@@ -321,6 +325,8 @@ static struct rnode * rnode_create(struct rnode *  parent,
 
         node->parent = parent;
 
+        node->chlen = 0;
+
         branch_hash(node);
         rnode_throw_event(node, RO_CREATE);
 
@@ -606,6 +612,13 @@ ssize_t rib_read(const char * path,
                 return -EFBIG;
         }
 
+        if (node->data == NULL) {
+                pthread_rwlock_unlock(&rib.lock);
+                return 0;
+        }
+
+        assert(node->len > 0);
+
         memcpy(data, node->data, node->len);
         rlen = node->len;
 
@@ -681,6 +694,60 @@ bool rib_has(const char * path)
         return node != NULL;
 }
 
+ssize_t rib_children(const char * path,
+                     char ***     children)
+{
+        struct list_head * p;
+
+        struct rnode * node;
+
+        ssize_t i = 0;
+
+        assert(path);
+        assert(children);
+
+        pthread_rwlock_rdlock(&rib.lock);
+
+        node = find_rnode_by_path(path);
+        if (node == NULL) {
+                pthread_rwlock_unlock(&rib.lock);
+                return -EPERM;
+        }
+
+        if (node->chlen == 0) {
+                pthread_rwlock_unlock(&rib.lock);
+                *children = NULL;
+                return 0;
+        }
+
+        *children = malloc(sizeof(**children) * node->chlen);
+        if (*children == NULL) {
+                pthread_rwlock_unlock(&rib.lock);
+                return -ENOMEM;
+        }
+
+        list_for_each(p, &node->children) {
+                struct child * c = list_entry(p, struct child, next);
+                (*children)[i] = strdup(c->node->name);
+                if ((*children)[i] == NULL) {
+                        ssize_t j;
+                        pthread_rwlock_unlock(&rib.lock);
+                        for (j = 0; j < i; ++j)
+                                free((*children)[j]);
+                        free(*children);
+                        return -ENOMEM;
+                }
+                ++i;
+        }
+
+        assert(i > 0);
+        assert((size_t) i == node->chlen);
+
+        pthread_rwlock_unlock(&rib.lock);
+
+        return i;
+}
+
 static struct rib_sub * rib_get_sub(uint32_t sid)
 {
         struct list_head * p;
diff --git a/src/lib/tests/rib_test.c b/src/lib/tests/rib_test.c
index 37503941..bad01083 100644
--- a/src/lib/tests/rib_test.c
+++ b/src/lib/tests/rib_test.c
@@ -46,6 +46,9 @@ int rib_test(int     argc,
 
         char tmp[RIB_MAX_PATH_LEN];
 
+        char ** kids;
+        ssize_t ch;
+
         struct timespec t = {0, 100 * BILLION};
 
         (void) argc;
@@ -73,6 +76,16 @@ int rib_test(int     argc,
                 return -1;
         }
 
+        ch = rib_children("/static_info", &kids);
+        if (ch != 0) {
+                printf("Wrong number of children returned.\n");
+                rib_fini();
+                while (ch > 0)
+                        free(kids[--ch]);
+                free(kids);
+                return -1;
+        }
+
         if (!rib_has("/static_info")) {
                 printf("Failed to find added element.\n");
                 rib_fini();
@@ -118,6 +131,17 @@ int rib_test(int     argc,
                 return -1;
         }
 
+        ch = rib_children("/static_info", &kids);
+        if (ch != 2) {
+                printf("Wrong number of children returned.\n");
+                rib_fini();
+                return -1;
+        }
+
+        while (ch > 0)
+                free(kids[--ch]);
+        free(kids);
+
         if (addr_chk != addr_size) {
                 printf("Failed to verify added element contents.\n");
                 rib_fini();