Re: [U-Boot] [PATCH v4 08/13] libfdt: Add fdt_path_offset_namelen

On Tue, Jul 05, 2016 at 10:26:41AM +0200, Maxime Ripard wrote:

Add a namelen variant of fdt_path_offset to retrieve the node offset using only a fixed number of characters.

Reviewed-by: Simon Glass sjg@chromium.org Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

---

include/libfdt.h | 16 +++++++++++++++- lib/libfdt/fdt_ro.c | 18 ++++++++++-------- 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/include/libfdt.h b/include/libfdt.h index 4643be5adf39..f13b01f08f71 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -365,6 +365,17 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset, */ int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);

+/**

• • fdt_path_offset_namelen - find a tree node based on substring
• • @fdt: pointer to the device tree blob
• • @path: full path of the node to locate
• • @namelen: number of characters of name to consider
• • Identical to fdt_path_offset(), but only examine the first
• • namelen characters of path for matching the node path.
• */

+int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);

/**

• fdt_path_offset - find a tree node by its full path
• @fdt: pointer to the device tree blob

@@ -387,7 +398,10 @@ int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);

• -FDT_ERR_BADSTRUCTURE,
• -FDT_ERR_TRUNCATED, standard meanings.

*/ -int fdt_path_offset(const void *fdt, const char *path); +static inline int fdt_path_offset(const void *fdt, const char *path) +{

• return fdt_path_offset_namelen(fdt, path, strlen(path));

+}

/**

• fdt_get_name - retrieve the name of a given node

diff --git a/lib/libfdt/fdt_ro.c b/lib/libfdt/fdt_ro.c index 6b737b211d2e..9cc98db6e2bf 100644 --- a/lib/libfdt/fdt_ro.c +++ b/lib/libfdt/fdt_ro.c @@ -145,10 +145,10 @@ int fdt_subnode_offset(const void *fdt, int parentoffset,

• "foo/bar:option" and "bar:option/otheroption", both of which happen, so
• first searching for either ':' or '/' does not work.

*/ -static const char *fdt_path_next_separator(const char *path) +static const char *fdt_path_next_separator(const char *path, int len) {

• const char *sep1 = strchr(path, '/');
• const char *sep2 = strchr(path, ':');

• const void *sep1 = memchr(path, '/', len);

• const void *sep2 = memchr(path, ':', len);

  if (sep1 && sep2) return (sep1 < sep2) ? sep1 : sep2;

@@ -158,9 +158,9 @@ static const char *fdt_path_next_separator(const char *path) return sep2; }

-int fdt_path_offset(const void *fdt, const char *path) +int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen) {

• const char *end = path + strlen(path);

• const char *end = path + namelen; const char *p = path; int offset = 0;

@@ -168,7 +168,7 @@ int fdt_path_offset(const void *fdt, const char *path)

/* see if we have an alias */ if (*path != '/') {

• const char *q = fdt_path_next_separator(path);
  

• const char *q = fdt_path_next_separator(path, namelen);
  
  

  if (!q) q = end;

@@ -181,14 +181,16 @@ int fdt_path_offset(const void *fdt, const char *path) p = q; }

• while (*p) {

• while (*p && (p < end)) {

The *p test should now be redundant. If you do see a \0 within the length specified by namelen, you should return FDT_ERR_BADPATH, rather than just truncating at the \0.

... and I just realised that path_offset_namelen() is already upstream, so I should fix that there too.

So what the hell is this downstream fdt_path_next_separator() nonsense for?

const char *q;

while (*p == '/')
	p++;

• if (*p == '\0' || *p == ':') return offset;

• q = fdt_path_next_separator(p);
  

• q = fdt_path_next_separator(p, end - p);
  

  if (!q) q = end;