1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
4 *
5 * Portions from U-Boot cmd_fdt.c (C) Copyright 2007
6 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
7 * Based on code written by:
8 *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
9 *   Matthew McClintock <msm@freescale.com>
10 */
11
12#include <assert.h>
13#include <ctype.h>
14#include <getopt.h>
15#include <stdio.h>
16#include <stdlib.h>
17#include <string.h>
18
19#include <libfdt.h>
20
21#include "util.h"
22
23enum display_mode {
24	MODE_SHOW_VALUE,	/* show values for node properties */
25	MODE_LIST_PROPS,	/* list the properties for a node */
26	MODE_LIST_SUBNODES,	/* list the subnodes of a node */
27};
28
29/* Holds information which controls our output and options */
30struct display_info {
31	int type;		/* data type (s/i/u/x or 0 for default) */
32	int size;		/* data size (1/2/4) */
33	enum display_mode mode;	/* display mode that we are using */
34	const char *default_val; /* default value if node/property not found */
35};
36
37static void report_error(const char *where, int err)
38{
39	fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
40}
41
42/**
43 * Displays data of a given length according to selected options
44 *
45 * If a specific data type is provided in disp, then this is used. Otherwise
46 * we try to guess the data type / size from the contents.
47 *
48 * @param disp		Display information / options
49 * @param data		Data to display
50 * @param len		Maximum length of buffer
51 * @return 0 if ok, -1 if data does not match format
52 */
53static int show_data(struct display_info *disp, const char *data, int len)
54{
55	int i, size;
56	const uint8_t *p = (const uint8_t *)data;
57	const char *s;
58	int value;
59	int is_string;
60	char fmt[3];
61
62	/* no data, don't print */
63	if (len == 0)
64		return 0;
65
66	is_string = (disp->type) == 's' ||
67		(!disp->type && util_is_printable_string(data, len));
68	if (is_string) {
69		if (data[len - 1] != '\0') {
70			fprintf(stderr, "Unterminated string\n");
71			return -1;
72		}
73		for (s = data; s - data < len; s += strlen(s) + 1) {
74			if (s != data)
75				printf(" ");
76			printf("%s", (const char *)s);
77		}
78		return 0;
79	}
80	size = disp->size;
81	if (size == -1) {
82		size = (len % 4) == 0 ? 4 : 1;
83	} else if (len % size) {
84		fprintf(stderr, "Property length must be a multiple of "
85				"selected data size\n");
86		return -1;
87	}
88	fmt[0] = '%';
89	fmt[1] = disp->type ? disp->type : 'd';
90	fmt[2] = '\0';
91	for (i = 0; i < len; i += size, p += size) {
92		if (i)
93			printf(" ");
94		value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
95			size == 2 ? (*p << 8) | p[1] : *p;
96		printf(fmt, value);
97	}
98	return 0;
99}
100
101/**
102 * List all properties in a node, one per line.
103 *
104 * @param blob		FDT blob
105 * @param node		Node to display
106 * @return 0 if ok, or FDT_ERR... if not.
107 */
108static int list_properties(const void *blob, int node)
109{
110	const struct fdt_property *data;
111	const char *name;
112	int prop;
113
114	prop = fdt_first_property_offset(blob, node);
115	do {
116		/* Stop silently when there are no more properties */
117		if (prop < 0)
118			return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
119		data = fdt_get_property_by_offset(blob, prop, NULL);
120		name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
121		if (name)
122			puts(name);
123		prop = fdt_next_property_offset(blob, prop);
124	} while (1);
125}
126
127#define MAX_LEVEL	32		/* how deeply nested we will go */
128
129/**
130 * List all subnodes in a node, one per line
131 *
132 * @param blob		FDT blob
133 * @param node		Node to display
134 * @return 0 if ok, or FDT_ERR... if not.
135 */
136static int list_subnodes(const void *blob, int node)
137{
138	int nextoffset;		/* next node offset from libfdt */
139	uint32_t tag;		/* current tag */
140	int level = 0;		/* keep track of nesting level */
141	const char *pathp;
142	int depth = 1;		/* the assumed depth of this node */
143
144	while (level >= 0) {
145		tag = fdt_next_tag(blob, node, &nextoffset);
146		switch (tag) {
147		case FDT_BEGIN_NODE:
148			pathp = fdt_get_name(blob, node, NULL);
149			if (level <= depth) {
150				if (pathp == NULL)
151					pathp = "/* NULL pointer error */";
152				if (*pathp == '\0')
153					pathp = "/";	/* root is nameless */
154				if (level == 1)
155					puts(pathp);
156			}
157			level++;
158			if (level >= MAX_LEVEL) {
159				printf("Nested too deep, aborting.\n");
160				return 1;
161			}
162			break;
163		case FDT_END_NODE:
164			level--;
165			if (level == 0)
166				level = -1;		/* exit the loop */
167			break;
168		case FDT_END:
169			return 1;
170		case FDT_PROP:
171			break;
172		default:
173			if (level <= depth)
174				printf("Unknown tag 0x%08X\n", tag);
175			return 1;
176		}
177		node = nextoffset;
178	}
179	return 0;
180}
181
182/**
183 * Show the data for a given node (and perhaps property) according to the
184 * display option provided.
185 *
186 * @param blob		FDT blob
187 * @param disp		Display information / options
188 * @param node		Node to display
189 * @param property	Name of property to display, or NULL if none
190 * @return 0 if ok, -ve on error
191 */
192static int show_data_for_item(const void *blob, struct display_info *disp,
193		int node, const char *property)
194{
195	const void *value = NULL;
196	int len, err = 0;
197
198	switch (disp->mode) {
199	case MODE_LIST_PROPS:
200		err = list_properties(blob, node);
201		break;
202
203	case MODE_LIST_SUBNODES:
204		err = list_subnodes(blob, node);
205		break;
206
207	default:
208		assert(property);
209		value = fdt_getprop(blob, node, property, &len);
210		if (value) {
211			if (show_data(disp, value, len))
212				err = -1;
213			else
214				printf("\n");
215		} else if (disp->default_val) {
216			puts(disp->default_val);
217		} else {
218			report_error(property, len);
219			err = -1;
220		}
221		break;
222	}
223
224	return err;
225}
226
227/**
228 * Run the main fdtget operation, given a filename and valid arguments
229 *
230 * @param disp		Display information / options
231 * @param filename	Filename of blob file
232 * @param arg		List of arguments to process
233 * @param arg_count	Number of arguments
234 * @param return 0 if ok, -ve on error
235 */
236static int do_fdtget(struct display_info *disp, const char *filename,
237		     char **arg, int arg_count, int args_per_step)
238{
239	char *blob;
240	const char *prop;
241	int i, node;
242
243	blob = utilfdt_read(filename);
244	if (!blob)
245		return -1;
246
247	for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
248		node = fdt_path_offset(blob, arg[i]);
249		if (node < 0) {
250			if (disp->default_val) {
251				puts(disp->default_val);
252				continue;
253			} else {
254				report_error(arg[i], node);
255				return -1;
256			}
257		}
258		prop = args_per_step == 1 ? NULL : arg[i + 1];
259
260		if (show_data_for_item(blob, disp, node, prop))
261			return -1;
262	}
263	return 0;
264}
265
266static const char *usage_msg =
267	"fdtget - read values from device tree\n"
268	"\n"
269	"Each value is printed on a new line.\n\n"
270	"Usage:\n"
271	"	fdtget <options> <dt file> [<node> <property>]...\n"
272	"	fdtget -p <options> <dt file> [<node> ]...\n"
273	"Options:\n"
274	"\t-t <type>\tType of data\n"
275	"\t-p\t\tList properties for each node\n"
276	"\t-l\t\tList subnodes for each node\n"
277	"\t-d\t\tDefault value to display when the property is "
278			"missing\n"
279	"\t-h\t\tPrint this help\n\n"
280	USAGE_TYPE_MSG;
281
282static void usage(const char *msg)
283{
284	if (msg)
285		fprintf(stderr, "Error: %s\n\n", msg);
286
287	fprintf(stderr, "%s", usage_msg);
288	exit(2);
289}
290
291int main(int argc, char *argv[])
292{
293	char *filename = NULL;
294	struct display_info disp;
295	int args_per_step = 2;
296
297	/* set defaults */
298	memset(&disp, '\0', sizeof(disp));
299	disp.size = -1;
300	disp.mode = MODE_SHOW_VALUE;
301	for (;;) {
302		int c = getopt(argc, argv, "d:hlpt:");
303		if (c == -1)
304			break;
305
306		switch (c) {
307		case 'h':
308		case '?':
309			usage(NULL);
310
311		case 't':
312			if (utilfdt_decode_type(optarg, &disp.type,
313					&disp.size))
314				usage("Invalid type string");
315			break;
316
317		case 'p':
318			disp.mode = MODE_LIST_PROPS;
319			args_per_step = 1;
320			break;
321
322		case 'l':
323			disp.mode = MODE_LIST_SUBNODES;
324			args_per_step = 1;
325			break;
326
327		case 'd':
328			disp.default_val = optarg;
329			break;
330		}
331	}
332
333	if (optind < argc)
334		filename = argv[optind++];
335	if (!filename)
336		usage("Missing filename");
337
338	argv += optind;
339	argc -= optind;
340
341	/* Allow no arguments, and silently succeed */
342	if (!argc)
343		return 0;
344
345	/* Check for node, property arguments */
346	if (args_per_step == 2 && (argc % 2))
347		usage("Must have an even number of arguments");
348
349	if (do_fdtget(&disp, filename, argv, argc, args_per_step))
350		return 1;
351	return 0;
352}
353