first commit for opensource

first commit for opensource

components/fs/vfs/tos_vfs_inode.c

@@ -0,0 +1,165 @@
+#include "tos_vfs.h"
+
+#if TOS_CFG_VFS_EN > 0u
+
+__STATIC__ TOS_LIST_DEFINE(k_vfs_inode_list);
+
+/*
+    1. filesystem
+    assume that we have registered a yaffs and mount it on /fs/yaffs,
+    we wanna find the inode of file /fs/yaffs/somedir/thefile,
+    we will return the inode of /fs/yaffs, and the relative_path will be somedir/thefile
+    2. device
+    if we are find a device's inode, like /dev/block/nand, the path must just be the path
+    of the device(/dev/block/nand), but on this condition, we would return a relative_path,
+    because device operation does not need a relative path.
+ */
+/*
+    I don't think an IOT system will have quit a lot of inodes, a linear search algorithm
+    should just be OK(mainly because it's simple ^_^).
+ */
+__STATIC__ vfs_inode_t *vfs_inode_search(const char *path, const char **relative_path)
+{
+    k_list_t *curr;
+    char *name = K_NULL;
+    int path_len, name_len;
+    vfs_inode_t *inode = K_NULL;
+
+    path_len = strlen(path);
+
+    TOS_LIST_FOR_EACH(curr, &k_vfs_inode_list) {
+        inode = TOS_LIST_ENTRY(curr, vfs_inode_t, list);
+        name = (char *)inode->name;
+        name_len = strlen(name);
+
+        /* eg. name is /dev/nand, path is /dev/na */
+        if (path_len < name_len) {
+            continue;
+        }
+
+        /* 1. name is /dev/nand, path is /dev/nand
+           2. name is /dev/nand, path is /dev/nand/invalid
+           3. name is /dev/nand, path is /dev/nand_tail
+           4. name is /fs/ramfs, path is /fs/ramfs
+           5. name is /fs/ramfs, path is /fs/ramfs/somefile
+           6. name is /fs/ramfs, path is /fs/ramfs_tail
+         */
+        if (VFS_INODE_IS_DEVICE(inode)) {
+            /* for a device, name and the path should just be the same, situation 1 */
+            if (path_len == name_len &&
+                strncmp(name, path, name_len) == 0) {
+                return inode;
+            }
+        } else if (VFS_INODE_IS_FILESYSTEM(inode)) {
+            if (path_len == name_len &&
+                strncmp(name, path, name_len) == 0) {
+                /* for a filesystem, situation 4 */
+                if (relative_path) {
+                    *relative_path = K_NULL;
+                }
+                return inode;
+            } else if (path_len > name_len &&
+                        strncmp(name, path, name_len) == 0 &&
+                        path[name_len] == '/') {
+                /* for a filesystem, situation 5 */
+                if (relative_path) {
+                    *relative_path = &path[name_len];
+                }
+                return inode;
+            }
+        }
+    }
+    return K_NULL;
+}
+
+__STATIC__ vfs_inode_t *vfs_inode_create(const char *name, int name_len)
+{
+    vfs_inode_t *inode = K_NULL;
+
+    inode = (vfs_inode_t *)tos_mmheap_calloc(1, VFS_INODE_SIZE(name_len));
+    if (!inode) {
+        return K_NULL;
+    }
+
+    strncpy(inode->name, name, name_len);
+    VFS_INODE_TYPE_SET(inode, VFS_INODE_TYPE_UNUSED);
+    tos_list_init(&inode->list);
+    tos_list_add(&inode->list, &k_vfs_inode_list);
+
+    return inode;
+}
+
+__KERNEL__ void vfs_inode_free(vfs_inode_t *inode)
+{
+    tos_list_del(&inode->list);
+    tos_mmheap_free((void *)inode);
+}
+
+__KERNEL__ void vfs_inode_refinc(vfs_inode_t *inode)
+{
+    if (inode->refs < VFS_INODE_REFS_MAX) {
+        ++inode->refs;
+    }
+}
+
+__KERNEL__ vfs_inode_t *vfs_inode_find(const char *path, const char **relative_path)
+{
+    vfs_inode_t *inode = K_NULL;
+
+    inode = vfs_inode_search(path, relative_path);
+    if (!inode) {
+        return K_NULL;
+    }
+
+    vfs_inode_refinc(inode);
+
+    return inode;
+}
+
+__KERNEL__ int vfs_inode_is_busy(vfs_inode_t *inode)
+{
+    return inode->refs > 0;
+}
+
+__KERNEL__ vfs_inode_t *vfs_inode_alloc(const char *name)
+{
+    int name_len;
+    vfs_inode_t *inode = K_NULL;
+
+    if (!name) {
+        return K_NULL;
+    }
+
+    name_len = strlen(name);
+    if (name_len > VFS_INODE_NAME_MAX) {
+        return K_NULL;
+    }
+
+    inode = vfs_inode_create(name, name_len);
+    if (!inode) {
+        return K_NULL;
+    }
+
+    ++inode->refs;
+
+    return inode;
+}
+
+__STATIC__ void vfs_inode_refdec(vfs_inode_t *inode)
+{
+    if (inode->refs) {
+        --inode->refs;
+    }
+}
+
+__KERNEL__ void vfs_inode_release(vfs_inode_t *inode)
+{
+    vfs_inode_refdec(inode);
+
+    if (inode->refs == 0) {
+        vfs_inode_free(inode);
+    }
+}
+
+#endif /* TOS_CFG_VFS_EN */
+