[PATCH 2/3] libfdt: Add fdt_get_path() function
David Gibson
david at gibson.dropbear.id.au
Thu Aug 30 14:54:04 EST 2007
This patch adds an fdt_get_path() function to libfdt, which returns
the full path of a given node in a caller supplied buffer.
Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
---
libfdt/fdt_ro.c | 66 ++++++++++++++++++++++++++++++++++++
libfdt/libfdt.h | 2 +
tests/Makefile.tests | 2 -
tests/get_path.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++
tests/run_tests.sh | 1
5 files changed, 161 insertions(+), 1 deletion(-)
Index: dtc/libfdt/fdt_ro.c
===================================================================
--- dtc.orig/libfdt/fdt_ro.c 2007-08-29 14:09:52.000000000 +1000
+++ dtc/libfdt/fdt_ro.c 2007-08-29 14:28:32.000000000 +1000
@@ -283,3 +283,69 @@
return prop->data;
}
+
+int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
+{
+ uint32_t tag;
+ int p = 0, overflow = 0;
+ int offset, nextoffset, namelen;
+ const char *name;
+
+ CHECK_HEADER(fdt);
+
+ tag = _fdt_next_tag(fdt, 0, &nextoffset);
+ if (tag != FDT_BEGIN_NODE)
+ return -FDT_ERR_BADSTRUCTURE;
+
+ if (buflen < 2)
+ return -FDT_ERR_NOSPACE;
+ buf[0] = '/';
+ p = 1;
+
+ while (offset < nodeoffset) {
+ offset = nextoffset;
+ tag = _fdt_next_tag(fdt, offset, &nextoffset);
+ switch (tag) {
+ case FDT_END:
+ return -FDT_ERR_BADOFFSET;
+
+ case FDT_BEGIN_NODE:
+ name = fdt_get_name(fdt, offset, &namelen);
+ if (!name)
+ return namelen;
+ if (overflow || ((p + namelen + 1) > buflen)) {
+ overflow++;
+ break;
+ }
+ memcpy(buf + p, name, namelen);
+ p += namelen;
+ buf[p++] = '/';
+ break;
+
+ case FDT_END_NODE:
+ if (overflow) {
+ overflow--;
+ break;
+ }
+ do {
+ p--;
+ } while (buf[p-1] != '/');
+ break;
+
+ case FDT_PROP:
+ case FDT_NOP:
+ break;
+
+ default:
+ return -FDT_ERR_BADSTRUCTURE;
+ }
+ }
+
+ if (overflow)
+ return -FDT_ERR_NOSPACE;
+
+ if (p > 1) /* special case so that root path is "/", not "" */
+ p--;
+ buf[p] = '\0';
+ return p;
+}
Index: dtc/tests/get_path.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ dtc/tests/get_path.c 2007-08-29 14:09:53.000000000 +1000
@@ -0,0 +1,91 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Testcase for fdt_get_path()
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "tests.h"
+#include "testdata.h"
+
+#define POISON ('\xff')
+
+void check_path_buf(void *fdt, const char *path, int pathlen, int buflen)
+{
+ int offset;
+ char buf[buflen+1];
+ int len;
+
+ offset = fdt_path_offset(fdt, path);
+ if (offset < 0)
+ FAIL("Couldn't find path \"%s\": %s", path, fdt_strerror(offset));
+
+ memset(buf, POISON, sizeof(buf)); /* poison the buffer */
+
+ len = fdt_get_path(fdt, offset, buf, buflen);
+ if (buflen <= pathlen) {
+ if (len != -FDT_ERR_NOSPACE)
+ FAIL("fdt_get_path([%d bytes]) returns %d with "
+ "insufficient buffer space", buflen, len);
+ } else {
+ if (len < 0)
+ FAIL("fdt_get_path([%d bytes]): %s", buflen,
+ fdt_strerror(len));
+ if (len != pathlen)
+ FAIL("fdt_get_path([%d bytes]) reports length %d "
+ "instead of %d", buflen, len, pathlen);
+ if (strcmp(buf, path) != 0)
+ FAIL("fdt_get_path([%d bytes]) returns \"%s\" "
+ "instead of \"%s\"", buflen, buf, path);
+ }
+
+ if (buf[buflen] != POISON)
+ FAIL("fdt_get_path([%d bytes]) overran buffer", buflen);
+}
+
+void check_path(void *fdt, const char *path)
+{
+ int pathlen = strlen(path);
+
+ check_path_buf(fdt, path, pathlen, 1024);
+ check_path_buf(fdt, path, pathlen, pathlen+1);
+ check_path_buf(fdt, path, pathlen, pathlen);
+}
+
+int main(int argc, char *argv[])
+{
+ void *fdt;
+
+ test_init(argc, argv);
+ fdt = load_blob_arg(argc, argv);
+
+ check_path(fdt, "/");
+ check_path(fdt, "/subnode1");
+ check_path(fdt, "/subnode2");
+ check_path(fdt, "/subnode1/subsubnode");
+ check_path(fdt, "/subnode2/subsubnode");
+
+ PASS();
+}
Index: dtc/tests/Makefile.tests
===================================================================
--- dtc.orig/tests/Makefile.tests 2007-08-29 14:09:52.000000000 +1000
+++ dtc/tests/Makefile.tests 2007-08-29 14:09:53.000000000 +1000
@@ -1,5 +1,5 @@
LIB_TESTS_L = root_node find_property subnode_offset path_offset \
- get_name getprop \
+ get_name getprop get_path \
notfound \
setprop_inplace nop_property nop_node \
sw_tree1 \
Index: dtc/tests/run_tests.sh
===================================================================
--- dtc.orig/tests/run_tests.sh 2007-08-29 14:09:52.000000000 +1000
+++ dtc/tests/run_tests.sh 2007-08-29 14:09:53.000000000 +1000
@@ -37,6 +37,7 @@
run_test path_offset $TREE
run_test get_name $TREE
run_test getprop $TREE
+ run_test get_path $TREE
run_test notfound $TREE
# Write-in-place tests
Index: dtc/libfdt/libfdt.h
===================================================================
--- dtc.orig/libfdt/libfdt.h 2007-08-29 14:09:52.000000000 +1000
+++ dtc/libfdt/libfdt.h 2007-08-29 14:10:28.000000000 +1000
@@ -136,6 +136,8 @@
return (void *)fdt_getprop(fdt, nodeoffset, name, lenp);
}
+int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
+
/* Write-in-place functions */
int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
const void *val, int len);
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