1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
4 */
5
6#include <assert.h>
7#include <ctype.h>
8#include <getopt.h>
9#include <stdio.h>
10#include <stdlib.h>
11#include <string.h>
12
13#include <libfdt.h>
14
15#include "util.h"
16
17/* These are the operations we support */
18enum oper_type {
19	OPER_WRITE_PROP,		/* Write a property in a node */
20	OPER_CREATE_NODE,		/* Create a new node */
21};
22
23struct display_info {
24	enum oper_type oper;	/* operation to perform */
25	int type;		/* data type (s/i/u/x or 0 for default) */
26	int size;		/* data size (1/2/4) */
27	int verbose;		/* verbose output */
28	int auto_path;		/* automatically create all path components */
29};
30
31
32/**
33 * Report an error with a particular node.
34 *
35 * @param name		Node name to report error on
36 * @param namelen	Length of node name, or -1 to use entire string
37 * @param err		Error number to report (-FDT_ERR_...)
38 */
39static void report_error(const char *name, int namelen, int err)
40{
41	if (namelen == -1)
42		namelen = strlen(name);
43	fprintf(stderr, "Error at '%1.*s': %s\n", namelen, name,
44		fdt_strerror(err));
45}
46
47/**
48 * Encode a series of arguments in a property value.
49 *
50 * @param disp		Display information / options
51 * @param arg		List of arguments from command line
52 * @param arg_count	Number of arguments (may be 0)
53 * @param valuep	Returns buffer containing value
54 * @param *value_len	Returns length of value encoded
55 */
56static int encode_value(struct display_info *disp, char **arg, int arg_count,
57			char **valuep, int *value_len)
58{
59	char *value = NULL;	/* holding area for value */
60	int value_size = 0;	/* size of holding area */
61	char *ptr;		/* pointer to current value position */
62	int len;		/* length of this cell/string/byte */
63	int ival;
64	int upto;	/* the number of bytes we have written to buf */
65	char fmt[3];
66
67	upto = 0;
68
69	if (disp->verbose)
70		fprintf(stderr, "Decoding value:\n");
71
72	fmt[0] = '%';
73	fmt[1] = disp->type ? disp->type : 'd';
74	fmt[2] = '\0';
75	for (; arg_count > 0; arg++, arg_count--, upto += len) {
76		/* assume integer unless told otherwise */
77		if (disp->type == 's')
78			len = strlen(*arg) + 1;
79		else
80			len = disp->size == -1 ? 4 : disp->size;
81
82		/* enlarge our value buffer by a suitable margin if needed */
83		if (upto + len > value_size) {
84			value_size = (upto + len) + 500;
85			value = realloc(value, value_size);
86			if (!value) {
87				fprintf(stderr, "Out of mmory: cannot alloc "
88					"%d bytes\n", value_size);
89				return -1;
90			}
91		}
92
93		ptr = value + upto;
94		if (disp->type == 's') {
95			memcpy(ptr, *arg, len);
96			if (disp->verbose)
97				fprintf(stderr, "\tstring: '%s'\n", ptr);
98		} else {
99			int *iptr = (int *)ptr;
100			sscanf(*arg, fmt, &ival);
101			if (len == 4)
102				*iptr = cpu_to_fdt32(ival);
103			else
104				*ptr = (uint8_t)ival;
105			if (disp->verbose) {
106				fprintf(stderr, "\t%s: %d\n",
107					disp->size == 1 ? "byte" :
108					disp->size == 2 ? "short" : "int",
109					ival);
110			}
111		}
112	}
113	*value_len = upto;
114	*valuep = value;
115	if (disp->verbose)
116		fprintf(stderr, "Value size %d\n", upto);
117	return 0;
118}
119
120static int store_key_value(void *blob, const char *node_name,
121		const char *property, const char *buf, int len)
122{
123	int node;
124	int err;
125
126	node = fdt_path_offset(blob, node_name);
127	if (node < 0) {
128		report_error(node_name, -1, node);
129		return -1;
130	}
131
132	err = fdt_setprop(blob, node, property, buf, len);
133	if (err) {
134		report_error(property, -1, err);
135		return -1;
136	}
137	return 0;
138}
139
140/**
141 * Create paths as needed for all components of a path
142 *
143 * Any components of the path that do not exist are created. Errors are
144 * reported.
145 *
146 * @param blob		FDT blob to write into
147 * @param in_path	Path to process
148 * @return 0 if ok, -1 on error
149 */
150static int create_paths(void *blob, const char *in_path)
151{
152	const char *path = in_path;
153	const char *sep;
154	int node, offset = 0;
155
156	/* skip leading '/' */
157	while (*path == '/')
158		path++;
159
160	for (sep = path; *sep; path = sep + 1, offset = node) {
161		/* equivalent to strchrnul(), but it requires _GNU_SOURCE */
162		sep = strchr(path, '/');
163		if (!sep)
164			sep = path + strlen(path);
165
166		node = fdt_subnode_offset_namelen(blob, offset, path,
167				sep - path);
168		if (node == -FDT_ERR_NOTFOUND) {
169			node = fdt_add_subnode_namelen(blob, offset, path,
170						       sep - path);
171		}
172		if (node < 0) {
173			report_error(path, sep - path, node);
174			return -1;
175		}
176	}
177
178	return 0;
179}
180
181/**
182 * Create a new node in the fdt.
183 *
184 * This will overwrite the node_name string. Any error is reported.
185 *
186 * TODO: Perhaps create fdt_path_offset_namelen() so we don't need to do this.
187 *
188 * @param blob		FDT blob to write into
189 * @param node_name	Name of node to create
190 * @return new node offset if found, or -1 on failure
191 */
192static int create_node(void *blob, const char *node_name)
193{
194	int node = 0;
195	char *p;
196
197	p = strrchr(node_name, '/');
198	if (!p) {
199		report_error(node_name, -1, -FDT_ERR_BADPATH);
200		return -1;
201	}
202	*p = '\0';
203
204	if (p > node_name) {
205		node = fdt_path_offset(blob, node_name);
206		if (node < 0) {
207			report_error(node_name, -1, node);
208			return -1;
209		}
210	}
211
212	node = fdt_add_subnode(blob, node, p + 1);
213	if (node < 0) {
214		report_error(p + 1, -1, node);
215		return -1;
216	}
217
218	return 0;
219}
220
221static int do_fdtput(struct display_info *disp, const char *filename,
222		    char **arg, int arg_count)
223{
224	char *value;
225	char *blob;
226	int len, ret = 0;
227
228	blob = utilfdt_read(filename);
229	if (!blob)
230		return -1;
231
232	switch (disp->oper) {
233	case OPER_WRITE_PROP:
234		/*
235		 * Convert the arguments into a single binary value, then
236		 * store them into the property.
237		 */
238		assert(arg_count >= 2);
239		if (disp->auto_path && create_paths(blob, *arg))
240			return -1;
241		if (encode_value(disp, arg + 2, arg_count - 2, &value, &len) ||
242			store_key_value(blob, *arg, arg[1], value, len))
243			ret = -1;
244		break;
245	case OPER_CREATE_NODE:
246		for (; ret >= 0 && arg_count--; arg++) {
247			if (disp->auto_path)
248				ret = create_paths(blob, *arg);
249			else
250				ret = create_node(blob, *arg);
251		}
252		break;
253	}
254	if (ret >= 0)
255		ret = utilfdt_write(filename, blob);
256
257	free(blob);
258	return ret;
259}
260
261static const char *usage_msg =
262	"fdtput - write a property value to a device tree\n"
263	"\n"
264	"The command line arguments are joined together into a single value.\n"
265	"\n"
266	"Usage:\n"
267	"	fdtput <options> <dt file> <node> <property> [<value>...]\n"
268	"	fdtput -c <options> <dt file> [<node>...]\n"
269	"Options:\n"
270	"\t-c\t\tCreate nodes if they don't already exist\n"
271	"\t-p\t\tAutomatically create nodes as needed for the node path\n"
272	"\t-t <type>\tType of data\n"
273	"\t-v\t\tVerbose: display each value decoded from command line\n"
274	"\t-h\t\tPrint this help\n\n"
275	USAGE_TYPE_MSG;
276
277static void usage(const char *msg)
278{
279	if (msg)
280		fprintf(stderr, "Error: %s\n\n", msg);
281
282	fprintf(stderr, "%s", usage_msg);
283	exit(2);
284}
285
286int main(int argc, char *argv[])
287{
288	struct display_info disp;
289	char *filename = NULL;
290
291	memset(&disp, '\0', sizeof(disp));
292	disp.size = -1;
293	disp.oper = OPER_WRITE_PROP;
294	for (;;) {
295		int c = getopt(argc, argv, "chpt:v");
296		if (c == -1)
297			break;
298
299		/*
300		 * TODO: add options to:
301		 * - delete property
302		 * - delete node (optionally recursively)
303		 * - rename node
304		 * - pack fdt before writing
305		 * - set amount of free space when writing
306		 * - expand fdt if value doesn't fit
307		 */
308		switch (c) {
309		case 'c':
310			disp.oper = OPER_CREATE_NODE;
311			break;
312		case 'h':
313		case '?':
314			usage(NULL);
315		case 'p':
316			disp.auto_path = 1;
317			break;
318		case 't':
319			if (utilfdt_decode_type(optarg, &disp.type,
320					&disp.size))
321				usage("Invalid type string");
322			break;
323
324		case 'v':
325			disp.verbose = 1;
326			break;
327		}
328	}
329
330	if (optind < argc)
331		filename = argv[optind++];
332	if (!filename)
333		usage("Missing filename");
334
335	argv += optind;
336	argc -= optind;
337
338	if (disp.oper == OPER_WRITE_PROP) {
339		if (argc < 1)
340			usage("Missing node");
341		if (argc < 2)
342			usage("Missing property");
343	}
344
345	if (do_fdtput(&disp, filename, argv, argc))
346		return 1;
347	return 0;
348}
349