From bbdbc7cb3abefda5bd998edbcf0508fe6256327d Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 29 Aug 2008 14:19:13 +1000 Subject: libfdt: Fix bugs in fdt_get_path() The current implementation of fdt_get_path() has a couple of bugs, fixed by this patch. First, contrary to its documentation, on success it returns the length of the node's path, rather than 0. The testcase is correspondingly wrong, and the patch fixes this as well. Second, in some circumstances, it will return -FDT_ERR_BADOFFSET instead of -FDT_ERR_NOSPACE when given insufficient buffer space. Specifically this happens when there is insufficient space even to hold the path's second last component. This behaviour is corrected, and the testcase updated to check it. Signed-off-by: David Gibson --- libfdt/fdt_ro.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'libfdt/fdt_ro.c') diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index b09a6e9eb..f559eeda0 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -320,9 +320,6 @@ int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen) for (offset = 0, depth = 0; (offset >= 0) && (offset <= nodeoffset); offset = fdt_next_node(fdt, offset, &depth)) { - if (pdepth < depth) - continue; /* overflowed buffer */ - while (pdepth > depth) { do { p--; @@ -330,14 +327,16 @@ int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen) pdepth--; } - name = fdt_get_name(fdt, offset, &namelen); - if (!name) - return namelen; - if ((p + namelen + 1) <= buflen) { - memcpy(buf + p, name, namelen); - p += namelen; - buf[p++] = '/'; - pdepth++; + if (pdepth >= depth) { + name = fdt_get_name(fdt, offset, &namelen); + if (!name) + return namelen; + if ((p + namelen + 1) <= buflen) { + memcpy(buf + p, name, namelen); + p += namelen; + buf[p++] = '/'; + pdepth++; + } } if (offset == nodeoffset) { @@ -347,7 +346,7 @@ int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen) if (p > 1) /* special case so that root path is "/", not "" */ p--; buf[p] = '\0'; - return p; + return 0; } } -- cgit v1.2.3-70-g09d2 From 9a6cf73a88ddab2e1ac39088f2806177982cc62c Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 20 Aug 2008 16:55:14 +1000 Subject: libfdt: Add function to explicitly expand aliases Kumar has already added alias expansion to fdt_path_offset(). However, in some circumstances it may be convenient for the user of libfdt to explicitly get the string expansion of an alias. This patch adds a function to do this, fdt_get_alias(), and uses it to implement fdt_path_offset(). Signed-off-by: David Gibson --- include/libfdt.h | 26 ++++++++++++++++++++++++++ libfdt/fdt_ro.c | 26 +++++++++++++++++++------- 2 files changed, 45 insertions(+), 7 deletions(-) (limited to 'libfdt/fdt_ro.c') diff --git a/include/libfdt.h b/include/libfdt.h index 5492a5352..7cad68c3c 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -458,6 +458,32 @@ static inline void *fdt_getprop_w(void *fdt, int nodeoffset, */ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset); +/** + * fdt_get_namelen - get alias based on substring + * @fdt: pointer to the device tree blob + * @name: name of the alias th look up + * @namelen: number of characters of name to consider + * + * Identical to fdt_get_alias(), but only examine the first namelen + * characters of name for matching the alias name. + */ +const char *fdt_get_alias_namelen(const void *fdt, + const char *name, int namelen); + +/** + * fdt_get_alias - retreive the path referenced by a given alias + * @fdt: pointer to the device tree blob + * @name: name of the alias th look up + * + * fdt_get_alias() retrieves the value of a given alias. That is, the + * value of the property named 'name' in the node /aliases. + * + * returns: + * a pointer to the expansion of the alias named 'name', of it exists + * NULL, if the given alias or the /aliases node does not exist + */ +const char *fdt_get_alias(const void *fdt, const char *name); + /** * fdt_get_path - determine the full path of a node * @fdt: pointer to the device tree blob diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index f559eeda0..b705f91ec 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -145,17 +145,12 @@ int fdt_path_offset(const void *fdt, const char *path) /* see if we have an alias */ if (*path != '/') { - const char *q; - int aliasoffset = fdt_path_offset(fdt, "/aliases"); - - if (aliasoffset < 0) - return -FDT_ERR_BADPATH; + const char *q = strchr(path, '/'); - q = strchr(path, '/'); if (!q) q = end; - p = fdt_getprop_namelen(fdt, aliasoffset, path, q - p, NULL); + p = fdt_get_alias_namelen(fdt, p, q - p); if (!p) return -FDT_ERR_BADPATH; offset = fdt_path_offset(fdt, p); @@ -306,6 +301,23 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset) return fdt32_to_cpu(*php); } +const char *fdt_get_alias_namelen(const void *fdt, + const char *name, int namelen) +{ + int aliasoffset; + + aliasoffset = fdt_path_offset(fdt, "/aliases"); + if (aliasoffset < 0) + return NULL; + + return fdt_getprop_namelen(fdt, aliasoffset, name, namelen, NULL); +} + +const char *fdt_get_alias(const void *fdt, const char *name) +{ + return fdt_get_alias_namelen(fdt, name, strlen(name)); +} + int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen) { int pdepth = 0, p = 0; -- cgit v1.2.3-70-g09d2