[Skiboot] [PATCH V3 1/3] core/device: Add function to return child node using name at substring "@"

[Athira Rajeev]

> On 16-Feb-2023, at 1:38 PM, Athira Rajeev <atrajeev at linux.vnet.ibm.com> wrote:
> 
> Add a function dt_find_by_name_substr() that returns the child node if
> it matches till first occurence at "@" of a given name, otherwise NULL.
> This is helpful for cases with node name like: "name at addr". In
> scenarios where nodes are added with "name at addr" format and if the
> value of "addr" is not known, that node can't be matched with node
> name or addr. Hence matching with substring as node name will return
> the expected result. Patch adds dt_find_by_name_substr() function
> and testcase for the same in core/test/run-device.c
> 
> Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
> ---
> Changelog:
> v2 -> v3:
> - After review comments from Mahesh, fixed the code
>  to consider string upto "@" for both input node name
>  as well as child node name. V2 version was comparing
>  input node name and child node name upto string length
>  of child name. But this will return wrong node if input
>  name is larger than child name. Because it will match
>  as substring for child name.
>  https://lists.ozlabs.org/pipermail/skiboot/2023-January/018596.html

Hi,

Looking for review comments for this V3 patch set. Please share your feedback.

Thanks
Athira

> 
> v1 -> v2:
> - Addressed review comment from Dan to update
>  the utility funtion to search and compare
>  upto "@". Renamed it as dt_find_by_name_substr.
> 
> core/device.c          | 35 +++++++++++++++++++++++++++++++++++
> core/test/run-device.c | 15 +++++++++++++++
> include/device.h       |  3 +++
> 3 files changed, 53 insertions(+)
> 
> diff --git a/core/device.c b/core/device.c
> index 2de37c74..26562235 100644
> --- a/core/device.c
> +++ b/core/device.c
> @@ -395,6 +395,41 @@ struct dt_node *dt_find_by_name(struct dt_node *root, const char *name)
> }
> 
> 
> +struct dt_node *dt_find_by_name_substr(struct dt_node *root, const char *name)
> +{
> +	struct dt_node *child, *match;
> +	char *node, *child_node = NULL;
> +
> +	node = malloc(strlen(name) + 1);
> +	if (!node)
> +		return NULL;
> +	memcpy(node, name, strlen(name));
> +	node[strlen(name)] = '\0';
> +	node = strtok(node, "@");
> +	list_for_each(&root->children, child, list) {
> +		child_node = malloc(strlen(child->name) + 1);
> +		if (!child_node)
> +			goto err;
> +		memcpy(child_node, child->name, strlen(child->name));
> +		child_node[strlen(child->name)] = '\0';
> +		child_node = strtok(child_node, "@");
> +		if (!strcmp(child_node, node)) {
> +			free(child_node);
> +			free(node);
> +			return child;
> +		}
> +
> +		match = dt_find_by_name_substr(child, name);
> +		if (match)
> +			return match;
> +	}
> +
> +	free(child_node);
> +err:
> +	free(node);
> +	return NULL;
> +}
> +
> struct dt_node *dt_new_check(struct dt_node *parent, const char *name)
> {
> 	struct dt_node *node = dt_find_by_name(parent, name);
> diff --git a/core/test/run-device.c b/core/test/run-device.c
> index 4a12382b..6997452e 100644
> --- a/core/test/run-device.c
> +++ b/core/test/run-device.c
> @@ -466,6 +466,21 @@ int main(void)
> 	new_prop_ph = dt_prop_get_u32(ut2, "something");
> 	assert(!(new_prop_ph == ev1_ph));
> 	dt_free(subtree);
> +
> +	/* Test dt_find_by_name_substr */
> +	root = dt_new_root("");
> +	addr1 = dt_new_addr(root, "node", 0x1);
> +	addr2 = dt_new_addr(root, "node0_1", 0x2);
> +	assert(dt_find_by_name(root, "node at 1") == addr1);
> +	assert(dt_find_by_name(root, "node0_1 at 2") == addr2);
> +	assert(dt_find_by_name_substr(root, "node at 1") == addr1);
> +	assert(dt_find_by_name_substr(root, "node0_1 at 2") == addr2);
> +	assert(dt_find_by_name_substr(root, "node0_") == NULL);
> +	assert(dt_find_by_name_substr(root, "node0_1") == addr2);
> +	assert(dt_find_by_name_substr(root, "node0@") == NULL);
> +	assert(dt_find_by_name_substr(root, "node0_@") == NULL);
> +	dt_free(root);
> +
> 	return 0;
> }
> 
> diff --git a/include/device.h b/include/device.h
> index 93fb90ff..b6a1a813 100644
> --- a/include/device.h
> +++ b/include/device.h
> @@ -184,6 +184,9 @@ struct dt_node *dt_find_by_path(struct dt_node *root, const char *path);
> /* Find a child node by name */
> struct dt_node *dt_find_by_name(struct dt_node *root, const char *name);
> 
> +/* Find a child node by name and substring */
> +struct dt_node *dt_find_by_name_substr(struct dt_node *root, const char *name);
> +
> /* Find a node by phandle */
> struct dt_node *dt_find_by_phandle(struct dt_node *root, u32 phandle);
> 
> -- 
> 2.27.0
> 
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