From: Nathan Whitehorn <nwhitehorn@xxxxxxxxxxx>
This can be useful in particular in the kernel when booting on systems
with FDT-emitting firmware that is out of date. Releases of kexec-tools
on ppc64 prior to the end of 2014 are notable examples of such.
Signed-off-by: Nathan Whitehorn <nwhitehorn@xxxxxxxxxxx>
---
fdtget.c | 4 +--
libfdt/fdt.c | 3 ++
libfdt/fdt_ro.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++---------
libfdt/libfdt.h | 5 ++-
4 files changed, 93 insertions(+), 19 deletions(-)
diff --git a/fdtget.c b/fdtget.c
index 6cc5242..34d8194 100644
--- a/fdtget.c
+++ b/fdtget.c
@@ -140,7 +140,6 @@ static int show_data(struct display_info *disp, const char *data, int len)
*/
static int list_properties(const void *blob, int node)
{
- const struct fdt_property *data;
const char *name;
int prop;
@@ -149,8 +148,7 @@ static int list_properties(const void *blob, int node)
/* Stop silently when there are no more properties */
if (prop < 0)
return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
- data = fdt_get_property_by_offset(blob, prop, NULL);
- name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
+ fdt_getprop_by_offset(blob, prop, &name, NULL);
if (name)
puts(name);
prop = fdt_next_property_offset(blob, prop);
diff --git a/libfdt/fdt.c b/libfdt/fdt.c
index fd13236..7855a17 100644
--- a/libfdt/fdt.c
+++ b/libfdt/fdt.c
@@ -123,6 +123,9 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
/* skip-name offset, length and value */
offset += sizeof(struct fdt_property) - FDT_TAGSIZE
+ fdt32_to_cpu(*lenp);
+ if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
+ ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
+ offset += 4;
break;
case FDT_END:
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index ce17814..a79b8ca 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -58,9 +58,10 @@
static int fdt_nodename_eq_(const void *fdt, int offset,
const char *s, int len)
{
- const char *p = fdt_offset_ptr(fdt, offset + FDT_TAGSIZE, len+1);
+ int olen;
+ const char *p = fdt_get_name(fdt, offset, &olen);
- if (!p)
+ if (!p || olen < len)
/* short match */
return 0;
@@ -233,16 +234,34 @@ int fdt_path_offset(const void *fdt, const char *path)
const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
{
const struct fdt_node_header *nh = fdt_offset_ptr_(fdt, nodeoffset);
+ const char *nameptr;
int err;
if (((err = fdt_check_header(fdt)) != 0)
|| ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0))
goto fail;
+ nameptr = nh->name;
+
+ if (fdt_version(fdt) < 0x10) {
+ /*
+ * For old FDT versions, match the naming conventions of V16:
+ * give only the leaf name (after all /). The actual tree
+ * contents are loosely checked.
+ */
+ const char *leaf;
+ leaf = strrchr(nameptr, '/');
+ if (leaf == NULL) {
+ err = -FDT_ERR_BADSTRUCTURE;
+ goto fail;
+ }
+ nameptr = leaf+1;
+ }
+
if (len)
- *len = strlen(nh->name);
+ *len = strlen(nameptr);
- return nh->name;
+ return nameptr;
fail:
if (len)
@@ -268,9 +287,9 @@ int fdt_next_property_offset(const void *fdt, int offset)
return nextprop_(fdt, offset);
}
-const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
- int offset,
- int *lenp)
+static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
+ int offset,
+ int *lenp)
{
int err;
const struct fdt_property *prop;
@@ -289,23 +308,44 @@ const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
return prop;
}
-const struct fdt_property *fdt_get_property_namelen(const void *fdt,
- int offset,
- const char *name,
- int namelen, int *lenp)
+const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
+ int offset,
+ int *lenp)
+{
+ /* Prior to version 16, properties may need realignment
+ * and this API does not work. fdt_getprop_*() will, however. */
+
+ if (fdt_version(fdt) < 0x10) {
+ if (lenp)
+ *lenp = -FDT_ERR_BADVERSION;
+ return NULL;
+ }
+
+ return fdt_get_property_by_offset_(fdt, offset, lenp);
+}
+
+static const struct fdt_property *fdt_get_property_namelen_(const void *fdt,
+ int offset,
+ const char *name,
+ int namelen,
+ int *lenp,
+ int *poffset)
{
for (offset = fdt_first_property_offset(fdt, offset);
(offset >= 0);
(offset = fdt_next_property_offset(fdt, offset))) {
const struct fdt_property *prop;
- if (!(prop = fdt_get_property_by_offset(fdt, offset, lenp))) {
+ if (!(prop = fdt_get_property_by_offset_(fdt, offset, lenp))) {
offset = -FDT_ERR_INTERNAL;
break;
}
if (fdt_string_eq_(fdt, fdt32_to_cpu(prop->nameoff),
- name, namelen))
+ name, namelen)) {
+ if (poffset)
+ *poffset = offset;
return prop;
+ }
}
if (lenp)
@@ -313,6 +353,25 @@ const struct fdt_property *fdt_get_property_namelen(const void *fdt,
return NULL;
}
+
+const struct fdt_property *fdt_get_property_namelen(const void *fdt,
+ int offset,
+ const char *name,
+ int namelen, int *lenp)
+{
+ /* Prior to version 16, properties may need realignment
+ * and this API does not work. fdt_getprop_*() will, however. */
+ if (fdt_version(fdt) < 0x10) {
+ if (lenp)
+ *lenp = -FDT_ERR_BADVERSION;
+ return NULL;
+ }
+
+ return fdt_get_property_namelen_(fdt, offset, name, namelen, lenp,
+ NULL);
+}
+
+
const struct fdt_property *fdt_get_property(const void *fdt,
int nodeoffset,
const char *name, int *lenp)
@@ -324,12 +383,18 @@ const struct fdt_property *fdt_get_property(const void *fdt,
const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
const char *name, int namelen, int *lenp)
{
+ int poffset;
const struct fdt_property *prop;
- prop = fdt_get_property_namelen(fdt, nodeoffset, name, namelen, lenp);
+ prop = fdt_get_property_namelen_(fdt, nodeoffset, name, namelen, lenp,
+ &poffset);
if (!prop)
return NULL;
+ /* Handle realignment */
+ if (fdt_version(fdt) < 0x10 && (poffset + sizeof(*prop)) % 8 &&
+ fdt32_to_cpu(prop->len) >= 8)
+ return prop->data + 4;
return prop->data;
}
@@ -338,11 +403,16 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
{
const struct fdt_property *prop;
- prop = fdt_get_property_by_offset(fdt, offset, lenp);
+ prop = fdt_get_property_by_offset_(fdt, offset, lenp);
if (!prop)
return NULL;
if (namep)
*namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
+
+ /* Handle realignment */
+ if (fdt_version(fdt) < 0x10 && (offset + sizeof(*prop)) % 8 &&
+ fdt32_to_cpu(prop->len) >= 8)
+ return prop->data + 4;
return prop->data;
}
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index baa882c..7ac3e8a 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -54,7 +54,7 @@
#include <libfdt_env.h>
#include <fdt.h>
-#define FDT_FIRST_SUPPORTED_VERSION 0x10
+#define FDT_FIRST_SUPPORTED_VERSION 0x02
#define FDT_LAST_SUPPORTED_VERSION 0x11
/* Error codes: informative error codes */
@@ -526,6 +526,9 @@ int fdt_next_property_offset(const void *fdt, int offset);
* fdt_property structure within the device tree blob at the given
* offset. If lenp is non-NULL, the length of the property value is
* also returned, in the integer pointed to by lenp.
+ *
+ * Note that this code only works on device tree versions >= 16. fdt_getprop()
+ * works on all versions.
*
* returns:
* pointer to the structure representing the property
--
2.15.1
--
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