Re: [PATCH 3/4] libfdt: Add fdt_setprop_namelen()

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 10260 bytes --]

On Wed, Dec 04, 2024 at 12:00:01AM +0530, Ayush Singh wrote:
> Allow specifying name length in setprop similar to
> `fdt_get_property_namelen` functions.
> 
> Signed-off-by: Ayush Singh <ayush@beagleboard.org>

Two really minor revisions suggested below, otherwise this looks good.

> ---
>  libfdt/fdt_rw.c    | 41 +++++++++++++++------------
>  libfdt/libfdt.h    | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++---
>  libfdt/version.lds |  2 ++
>  3 files changed, 103 insertions(+), 21 deletions(-)
> 
> diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
> index 3621d3651d3f4bd82b7af66c60d023e3139add03..33c60063cd721a147a3c6c0e70450c98d8dbd772 100644
> --- a/libfdt/fdt_rw.c
> +++ b/libfdt/fdt_rw.c
> @@ -124,31 +124,33 @@ static int fdt_splice_string_(void *fdt, int newlen)
>   *	allocated. Ignored if can_assume(NO_ROLLBACK)
>   * @return offset of string in the string table (whether found or added)
>   */
> -static int fdt_find_add_string_(void *fdt, const char *s, int *allocated)
> +static int fdt_find_add_string_(void *fdt, const char *s, int slen,
> +				int *allocated)
>  {
>  	char *strtab = (char *)fdt + fdt_off_dt_strings(fdt);
>  	const char *p;
>  	char *new;
> -	int len = strlen(s) + 1;
>  	int err;
>  
>  	if (!can_assume(NO_ROLLBACK))
>  		*allocated = 0;
>  
> -	p = fdt_find_string_(strtab, fdt_size_dt_strings(fdt), s);
> +	p = fdt_find_string_len_(strtab, fdt_size_dt_strings(fdt), s, slen);
>  	if (p)
>  		/* found it */
>  		return (p - strtab);
>  
>  	new = strtab + fdt_size_dt_strings(fdt);
> -	err = fdt_splice_string_(fdt, len);
> +	err = fdt_splice_string_(fdt, slen + 1);
>  	if (err)
>  		return err;
>  
>  	if (!can_assume(NO_ROLLBACK))
>  		*allocated = 1;
>  
> -	memcpy(new, s, len);
> +	memcpy(new, s, slen);
> +	new[slen] = '\0';
> +
>  	return (new - strtab);
>  }
>  
> @@ -182,12 +184,14 @@ int fdt_del_mem_rsv(void *fdt, int n)
>  }
>  
>  static int fdt_resize_property_(void *fdt, int nodeoffset, const char *name,
> -				int len, struct fdt_property **prop)
> +				int namelen, int len,
> +				struct fdt_property **prop)

Nit: I'd prefer to see name and namelen grouped together on a line,
then len and prop can go on the next.

>  {
>  	int oldlen;
>  	int err;
>  
> -	*prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
> +	*prop = fdt_get_property_namelen_w(fdt, nodeoffset, name, namelen,
> +					   &oldlen);
>  	if (!*prop)
>  		return oldlen;
>  
> @@ -200,7 +204,7 @@ static int fdt_resize_property_(void *fdt, int nodeoffset, const char *name,
>  }
>  
>  static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
> -			     int len, struct fdt_property **prop)
> +			     int namelen, int len, struct fdt_property **prop)
>  {
>  	int proplen;
>  	int nextoffset;
> @@ -211,7 +215,7 @@ static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
>  	if ((nextoffset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
>  		return nextoffset;
>  
> -	namestroff = fdt_find_add_string_(fdt, name, &allocated);
> +	namestroff = fdt_find_add_string_(fdt, name, namelen, &allocated);
>  	if (namestroff < 0)
>  		return namestroff;
>  
> @@ -255,17 +259,18 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name)
>  	return 0;
>  }
>  
> -int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
> -			    int len, void **prop_data)
> +int fdt_setprop_namelen_placeholder(void *fdt, int nodeoffset, const char *name,
> +				    int namelen, int len, void **prop_data)

Sorry, I gave you bad advice in my earlier message.  I'd prefer this
to be "fdt_setprop_placeholder_namelen()" (compare
"fdt_add_subnode_namelen()").

>  {
>  	struct fdt_property *prop;
>  	int err;
>  
>  	FDT_RW_PROBE(fdt);
>  
> -	err = fdt_resize_property_(fdt, nodeoffset, name, len, &prop);
> +	err = fdt_resize_property_(fdt, nodeoffset, name, namelen, len, &prop);
>  	if (err == -FDT_ERR_NOTFOUND)
> -		err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
> +		err = fdt_add_property_(fdt, nodeoffset, name, namelen, len,
> +					&prop);
>  	if (err)
>  		return err;
>  
> @@ -273,13 +278,14 @@ int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
>  	return 0;
>  }
>  
> -int fdt_setprop(void *fdt, int nodeoffset, const char *name,
> -		const void *val, int len)
> +int fdt_setprop_namelen(void *fdt, int nodeoffset, const char *name,
> +			int namelen, const void *val, int len)
>  {
>  	void *prop_data;
>  	int err;
>  
> -	err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data);
> +	err = fdt_setprop_namelen_placeholder(fdt, nodeoffset, name, namelen,
> +					      len, &prop_data);
>  	if (err)
>  		return err;
>  
> @@ -307,7 +313,8 @@ int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
>  		prop->len = cpu_to_fdt32(newlen);
>  		memcpy(prop->data + oldlen, val, len);
>  	} else {
> -		err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
> +		err = fdt_add_property_(fdt, nodeoffset, name, strlen(name),
> +					len, &prop);
>  		if (err)
>  			return err;
>  		memcpy(prop->data, val, len);
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 7d0c252a34970f4ca841935f8088410a3970127a..c9c81f039365b6d244932786a84a05f065e67c33 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -1666,6 +1666,38 @@ int fdt_del_mem_rsv(void *fdt, int n);
>   */
>  int fdt_set_name(void *fdt, int nodeoffset, const char *name);
>  
> +/**
> + * fdt_setprop_namelen - create or change a property
> + * @fdt: pointer to the device tree blob
> + * @nodeoffset: offset of the node whose property to change
> + * @name: name of the property to change
> + * @namelen: length of the name
> + * @val: pointer to data to set the property value to
> + * @len: length of the property value
> + *
> + * fdt_setprop_namelen() sets the value of the named property in the given
> + * node to the given value and length, creating the property if it
> + * does not already exist.
> + *
> + * This function may insert or delete data from the blob, and will
> + * therefore change the offsets of some existing nodes.
> + *
> + * returns:
> + *	0, on success
> + *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
> + *		contain the new property value
> + *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
> + *	-FDT_ERR_BADLAYOUT,
> + *	-FDT_ERR_BADMAGIC,
> + *	-FDT_ERR_BADVERSION,
> + *	-FDT_ERR_BADSTATE,
> + *	-FDT_ERR_BADSTRUCTURE,
> + *	-FDT_ERR_BADLAYOUT,
> + *	-FDT_ERR_TRUNCATED, standard meanings
> + */
> +int fdt_setprop_namelen(void *fdt, int nodeoffset, const char *name,
> +			int namelen, const void *val, int len);
> +
>  /**
>   * fdt_setprop - create or change a property
>   * @fdt: pointer to the device tree blob
> @@ -1694,8 +1726,44 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name);
>   *	-FDT_ERR_BADLAYOUT,
>   *	-FDT_ERR_TRUNCATED, standard meanings
>   */
> -int fdt_setprop(void *fdt, int nodeoffset, const char *name,
> -		const void *val, int len);
> +static inline int fdt_setprop(void *fdt, int nodeoffset, const char *name,
> +			      const void *val, int len)
> +{
> +	return fdt_setprop_namelen(fdt, nodeoffset, name, strlen(name), val,
> +				   len);
> +}
> +
> +/**
> + * fdt_setprop_namelen_placeholder - allocate space for a property
> + * @fdt: pointer to the device tree blob
> + * @nodeoffset: offset of the node whose property to change
> + * @name: name of the property to change
> + * @namelen: length of the name
> + * @len: length of the property value
> + * @prop_data: return pointer to property data
> + *
> + * fdt_setprop_namelen_placeholder() allocates the named property in the given node.
> + * If the property exists it is resized. In either case a pointer to the
> + * property data is returned.
> + *
> + * This function may insert or delete data from the blob, and will
> + * therefore change the offsets of some existing nodes.
> + *
> + * returns:
> + *	0, on success
> + *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
> + *		contain the new property value
> + *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
> + *	-FDT_ERR_BADLAYOUT,
> + *	-FDT_ERR_BADMAGIC,
> + *	-FDT_ERR_BADVERSION,
> + *	-FDT_ERR_BADSTATE,
> + *	-FDT_ERR_BADSTRUCTURE,
> + *	-FDT_ERR_BADLAYOUT,
> + *	-FDT_ERR_TRUNCATED, standard meanings
> + */
> +int fdt_setprop_namelen_placeholder(void *fdt, int nodeoffset, const char *name,
> +				    int namelen, int len, void **prop_data);
>  
>  /**
>   * fdt_setprop_placeholder - allocate space for a property
> @@ -1725,8 +1793,13 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
>   *	-FDT_ERR_BADLAYOUT,
>   *	-FDT_ERR_TRUNCATED, standard meanings
>   */
> -int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
> -			    int len, void **prop_data);
> +static inline int fdt_setprop_placeholder(void *fdt, int nodeoffset,
> +					  const char *name, int len,
> +					  void **prop_data)
> +{
> +	return fdt_setprop_namelen_placeholder(fdt, nodeoffset, name,
> +					       strlen(name), len, prop_data);
> +}
>  
>  /**
>   * fdt_setprop_u32 - set a property to a 32-bit integer
> diff --git a/libfdt/version.lds b/libfdt/version.lds
> index 989cd89f1051ce59255a3b3e60493be4e5e985cc..76ba8f6758cef16efbad2813464e824de594b646 100644
> --- a/libfdt/version.lds
> +++ b/libfdt/version.lds
> @@ -43,6 +43,7 @@ LIBFDT_1.2 {
>  		fdt_add_mem_rsv;
>  		fdt_del_mem_rsv;
>  		fdt_set_name;
> +		fdt_setprop_namelen;
>  		fdt_setprop;
>  		fdt_delprop;
>  		fdt_add_subnode_namelen;
> @@ -71,6 +72,7 @@ LIBFDT_1.2 {
>  		fdt_find_max_phandle;
>  		fdt_generate_phandle;
>  		fdt_check_full;
> +		fdt_setprop_namelen_placeholder;
>  		fdt_setprop_placeholder;
>  		fdt_property_placeholder;
>  		fdt_header_size_;
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]