Re: [PATCH v2 1/3] fdt: Add a function to count strings

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 8574 bytes --]

On Thu, Jul 16, 2015 at 01:10:19PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> Given a device tree node and a property name, the fdt_count_strings()
> function counts the number of strings found in the property value.
> 
> This also adds a new error code, FDT_ERR_BADVALUE, that the function
> returns when it encounters a non-NUL-terminated string list.
> 
> Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
> Changes in v2:
> - return FDT_ERR_BADVALUE error code for non-NUL-terminated properties
> - add tests to cover non-NUL-terminated properties

This looks good, except for the function name.  I'd prefer to see it
called 'fdt_stringlist_count()' to match the existing
'fdt_stringlist_contains()'.

> 
>  libfdt/fdt_ro.c      | 25 ++++++++++++++++
>  libfdt/libfdt.h      | 19 +++++++++++-
>  tests/.gitignore     |  1 +
>  tests/Makefile.tests |  1 +
>  tests/run_tests.sh   |  3 ++
>  tests/strings.c      | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/strings.dts    | 12 ++++++++
>  7 files changed, 142 insertions(+), 1 deletion(-)
>  create mode 100644 tests/strings.c
>  create mode 100644 tests/strings.dts
> 
> diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
> index a65e4b5b72b6..cf55c71df79c 100644
> --- a/libfdt/fdt_ro.c
> +++ b/libfdt/fdt_ro.c
> @@ -538,6 +538,31 @@ int fdt_stringlist_contains(const char *strlist, int listlen, const char *str)
>  	return 0;
>  }
>  
> +int fdt_count_strings(const void *fdt, int nodeoffset, const char *property)
> +{
> +	const char *list, *end;
> +	int length, count = 0;
> +
> +	list = fdt_getprop(fdt, nodeoffset, property, &length);
> +	if (!list)
> +		return -length;
> +
> +	end = list + length;
> +
> +	while (list < end) {
> +		length = strnlen(list, end - list) + 1;
> +
> +		/* Abort if the last string isn't properly NUL-terminated. */
> +		if (list + length > end)
> +			return -FDT_ERR_BADVALUE;
> +
> +		list += length;
> +		count++;
> +	}
> +
> +	return count;
> +}
> +
>  int fdt_node_check_compatible(const void *fdt, int nodeoffset,
>  			      const char *compatible)
>  {
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 1054512814bc..bf60c1593e4e 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -121,7 +121,12 @@
>  	/* FDT_ERR_BADNCELLS: Device tree has a #address-cells, #size-cells
>  	 * or similar property with a bad format or value */
>  
> -#define FDT_ERR_MAX		14
> +#define FDT_ERR_BADVALUE	15
> +	/* FDT_ERR_BADVALUE: Device tree has a property with an unexpected
> +	 * value. For example: a property expected to contain a string list
> +	 * is not NUL-terminated within the length of its value. */
> +
> +#define FDT_ERR_MAX		15
>  
>  /**********************************************************************/
>  /* Low-level functions (you probably don't need these)                */
> @@ -868,6 +873,18 @@ int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
>   */
>  int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
>  
> +/**
> + * fdt_count_strings - count the number of strings in a string list
> + * @fdt: pointer to the device tree blob
> + * @nodeoffset: offset of a tree node
> + * @property: name of the property containing the string list
> + * @return:
> + *   the number of strings in the given property
> + *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
> + *   -FDT_ERR_NOTFOUND if the property does not exist
> + */
> +int fdt_count_strings(const void *fdt, int nodeoffset, const char *property);
> +
>  /**********************************************************************/
>  /* Read-only functions (addressing related)                           */
>  /**********************************************************************/
> diff --git a/tests/.gitignore b/tests/.gitignore
> index 5656555f9cbc..09a1d3b84f6f 100644
> --- a/tests/.gitignore
> +++ b/tests/.gitignore
> @@ -49,6 +49,7 @@ tmp.*
>  /setprop_inplace
>  /sized_cells
>  /string_escapes
> +/strings
>  /subnode_iterate
>  /subnode_offset
>  /supernode_atdepth_offset
> diff --git a/tests/Makefile.tests b/tests/Makefile.tests
> index 9adedecdff3d..415e4d670f2c 100644
> --- a/tests/Makefile.tests
> +++ b/tests/Makefile.tests
> @@ -9,6 +9,7 @@ LIB_TESTS_L = get_mem_rsv \
>  	sized_cells \
>  	notfound \
>  	addr_size_cells \
> +	strings \
>  	setprop_inplace nop_property nop_node \
>  	sw_tree1 \
>  	move_and_save mangle-layout nopulate \
> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
> index 5268293434af..92ee96340c29 100755
> --- a/tests/run_tests.sh
> +++ b/tests/run_tests.sh
> @@ -198,6 +198,9 @@ libfdt_tests () {
>      run_dtc_test -I dts -O dtb -o addresses.test.dtb addresses.dts
>      run_test addr_size_cells addresses.test.dtb
>  
> +    run_dtc_test -I dts -O dtb -o strings.test.dtb strings.dts
> +    run_test strings strings.test.dtb
> +
>      # Sequential write tests
>      run_test sw_tree1
>      tree1_tests sw_tree1.test.dtb
> diff --git a/tests/strings.c b/tests/strings.c
> new file mode 100644
> index 000000000000..e10d9ece5a3e
> --- /dev/null
> +++ b/tests/strings.c
> @@ -0,0 +1,82 @@
> +/*
> + * libfdt - Flat Device Tree manipulation
> + *	Testcase for string handling
> + * Copyright (C) 2015 NVIDIA 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
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdint.h>
> +
> +#include <libfdt.h>
> +
> +#include "tests.h"
> +#include "testdata.h"
> +
> +static void check_expected_failure(const void *fdt, const char *path,
> +				   const char *property)
> +{
> +	int offset, err;
> +
> +	offset = fdt_path_offset(fdt, "/");
> +	if (offset < 0)
> +		FAIL("Couldn't find path %s", path);
> +
> +	err = fdt_count_strings(fdt, offset, "#address-cells");
> +	if (err != -FDT_ERR_BADVALUE)
> +		FAIL("unexpectedly succeeded in parsing #address-cells\n");
> +}
> +
> +static void check_string_count(const void *fdt, const char *path,
> +			       const char *property, int count)
> +{
> +	int offset, err;
> +
> +	offset = fdt_path_offset(fdt, path);
> +	if (offset < 0)
> +		FAIL("Couldn't find path %s", path);
> +
> +	err = fdt_count_strings(fdt, offset, property);
> +	if (err < 0)
> +		FAIL("Couldn't count strings in property %s of node %s: %d\n",
> +		     property, path, err);
> +
> +	if (err != count)
> +		FAIL("String count for property %s of node %s is %d instead of %d\n",
> +		     path, property, err, count);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	void *fdt;
> +
> +	if (argc != 2)
> +		CONFIG("Usage: %s <dtb file>\n", argv[0]);
> +
> +	test_init(argc, argv);
> +	fdt = load_blob(argv[1]);
> +
> +	check_expected_failure(fdt, "/", "#address-cells");
> +	check_expected_failure(fdt, "/", "#size-cells");
> +
> +	check_string_count(fdt, "/", "compatible", 1);
> +	check_string_count(fdt, "/device", "compatible", 2);
> +	check_string_count(fdt, "/device", "big-endian", 0);
> +
> +	PASS();
> +}
> diff --git a/tests/strings.dts b/tests/strings.dts
> new file mode 100644
> index 000000000000..1e4d3140458f
> --- /dev/null
> +++ b/tests/strings.dts
> @@ -0,0 +1,12 @@
> +/dts-v1/;
> +
> +/ {
> +	compatible = "test-strings";
> +	#address-cells = <2>;
> +	#size-cells = <2>;
> +
> +	device {
> +		compatible = "foo", "bar";
> +		big-endian;
> +	};
> +};

-- 
David Gibson			| 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: Type: application/pgp-signature, Size: 819 bytes --]