[fsfdt] Skip addition of existing subnodes
While appending FDT, it is possible that the traversed subnode is
already present. In those cases, skip those instead of failing.
Test: atest libfsfdt_test
Bug: 324983012
Change-Id: I8b9e881f3b7a212cdf3ae69c5e3f3fd130dd7b96
diff --git a/virtualizationmanager/fsfdt/src/lib.rs b/virtualizationmanager/fsfdt/src/lib.rs
index 549df04..84e50c1 100644
--- a/virtualizationmanager/fsfdt/src/lib.rs
+++ b/virtualizationmanager/fsfdt/src/lib.rs
@@ -26,8 +26,8 @@
/// Creates a Fdt from /proc/device-tree style directory by wrapping a mutable slice
fn from_fs(fs_path: &Path, fdt_buffer: &'a mut [u8]) -> Result<&'a mut Self>;
- /// Appends a FDT from /proc/device-tree style directory at the given node path
- fn append(&mut self, fdt_node_path: &CStr, fs_path: &Path) -> Result<()>;
+ /// Overlay an FDT from /proc/device-tree style directory at the given node path
+ fn overlay_onto(&mut self, fdt_node_path: &CStr, fs_path: &Path) -> Result<()>;
}
impl<'a> FsFdt<'a> for Fdt {
@@ -35,12 +35,12 @@
let fdt = Fdt::create_empty_tree(fdt_buffer)
.map_err(|e| anyhow!("Failed to create FDT, {e:?}"))?;
- fdt.append(&CString::new("").unwrap(), fs_path)?;
+ fdt.overlay_onto(&CString::new("").unwrap(), fs_path)?;
Ok(fdt)
}
- fn append(&mut self, fdt_node_path: &CStr, fs_path: &Path) -> Result<()> {
+ fn overlay_onto(&mut self, fdt_node_path: &CStr, fs_path: &Path) -> Result<()> {
// Recursively traverse fs_path with DFS algorithm.
let mut stack = vec![fs_path.to_path_buf()];
while let Some(dir_path) = stack.pop() {
@@ -56,7 +56,7 @@
let mut node = self
.node_mut(&fdt_path)
.map_err(|e| anyhow!("Failed to write FDT, {e:?}"))?
- .ok_or_else(|| anyhow!("Failed to find {fdt_node_path:?} in FDT"))?;
+ .ok_or_else(|| anyhow!("Failed to find {fdt_path:?} in FDT"))?;
let mut subnode_names = vec![];
let entries =
@@ -90,9 +90,21 @@
// FDT library may omit address in node name when comparing their name, so sort to add
// node without address first.
subnode_names.sort();
- let subnode_names_c_str: Vec<_> = subnode_names.iter().map(|x| x.as_c_str()).collect();
- node.add_subnodes(&subnode_names_c_str)
- .map_err(|e| anyhow!("Failed to add node, {e:?}"))?;
+ let subnode_names: Vec<_> = subnode_names
+ .iter()
+ .filter_map(|name| {
+ // Filter out subnode names which are already present in the target parent node!
+ let name = name.as_c_str();
+ let is_present_res = node.as_node().subnode(name);
+ match is_present_res {
+ Ok(Some(_)) => None,
+ Ok(None) => Some(Ok(name)),
+ Err(e) => Some(Err(e)),
+ }
+ })
+ .collect::<Result<_, _>>()
+ .map_err(|e| anyhow!("Failed to filter subnodes, {e:?}"))?;
+ node.add_subnodes(&subnode_names).map_err(|e| anyhow!("Failed to add node, {e:?}"))?;
}
Ok(())
@@ -149,5 +161,8 @@
let actual = dts_from_dtb(file.path());
assert_eq!(&expected, &actual);
+ // Again append fdt from TEST_FS_FDT_ROOT_PATH at root & ensure it succeeds when some
+ // subnode are already present.
+ fdt.overlay_onto(&CString::new("/").unwrap(), fs_path).unwrap();
}
}