1 /* $NetBSD: fdtget.c,v 1.1.1.3 2019/12/22 12:34:03 skrll Exp $ */
2
3 // SPDX-License-Identifier: GPL-2.0-or-later
4 /*
5 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
6 *
7 * Portions from U-Boot cmd_fdt.c (C) Copyright 2007
8 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
9 * Based on code written by:
10 * Pantelis Antoniou <pantelis.antoniou@gmail.com> and
11 * Matthew McClintock <msm@freescale.com>
12 */
13
14 #include <assert.h>
15 #include <ctype.h>
16 #include <getopt.h>
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <string.h>
20
21 #include <libfdt.h>
22
23 #include "util.h"
24
25 enum display_mode {
26 MODE_SHOW_VALUE, /* show values for node properties */
27 MODE_LIST_PROPS, /* list the properties for a node */
28 MODE_LIST_SUBNODES, /* list the subnodes of a node */
29 };
30
31 /* Holds information which controls our output and options */
32 struct display_info {
33 int type; /* data type (s/i/u/x or 0 for default) */
34 int size; /* data size (1/2/4) */
35 enum display_mode mode; /* display mode that we are using */
36 const char *default_val; /* default value if node/property not found */
37 };
38
report_error(const char * where,int err)39 static void report_error(const char *where, int err)
40 {
41 fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
42 }
43
44 /**
45 * Shows a list of cells in the requested format
46 *
47 * @param disp Display information / options
48 * @param data Data to display
49 * @param len Maximum length of buffer
50 * @param size Data size to use for display (e.g. 4 for 32-bit)
51 * @return 0 if ok, -1 on error
52 */
show_cell_list(struct display_info * disp,const char * data,int len,int size)53 static int show_cell_list(struct display_info *disp, const char *data, int len,
54 int size)
55 {
56 const uint8_t *p = (const uint8_t *)data;
57 char fmt[3];
58 int value;
59 int i;
60
61 fmt[0] = '%';
62 fmt[1] = disp->type ? disp->type : 'd';
63 fmt[2] = '\0';
64 for (i = 0; i < len; i += size, p += size) {
65 if (i)
66 printf(" ");
67 value = size == 4 ? fdt32_ld((const fdt32_t *)p) :
68 size == 2 ? (*p << 8) | p[1] : *p;
69 printf(fmt, value);
70 }
71
72 return 0;
73 }
74
75 /**
76 * Displays data of a given length according to selected options
77 *
78 * If a specific data type is provided in disp, then this is used. Otherwise
79 * we try to guess the data type / size from the contents.
80 *
81 * @param disp Display information / options
82 * @param data Data to display
83 * @param len Maximum length of buffer
84 * @return 0 if ok, -1 if data does not match format
85 */
show_data(struct display_info * disp,const char * data,int len)86 static int show_data(struct display_info *disp, const char *data, int len)
87 {
88 int size;
89 const char *s;
90 int is_string;
91
92 /* no data, don't print */
93 if (len == 0)
94 return 0;
95
96 is_string = (disp->type) == 's' ||
97 (!disp->type && util_is_printable_string(data, len));
98 if (is_string) {
99 if (data[len - 1] != '\0') {
100 fprintf(stderr, "Unterminated string\n");
101 return -1;
102 }
103 for (s = data; s - data < len; s += strlen(s) + 1) {
104 if (s != data)
105 printf(" ");
106 printf("%s", (const char *)s);
107 }
108 return 0;
109 }
110 size = disp->size;
111 if (size == -1) {
112 size = (len % 4) == 0 ? 4 : 1;
113 } else if (len % size) {
114 fprintf(stderr, "Property length must be a multiple of "
115 "selected data size\n");
116 return -1;
117 }
118
119 return show_cell_list(disp, data, len, size);
120 }
121
122 /**
123 * List all properties in a node, one per line.
124 *
125 * @param blob FDT blob
126 * @param node Node to display
127 * @return 0 if ok, or FDT_ERR... if not.
128 */
list_properties(const void * blob,int node)129 static int list_properties(const void *blob, int node)
130 {
131 const char *name;
132 int prop;
133
134 prop = fdt_first_property_offset(blob, node);
135 do {
136 /* Stop silently when there are no more properties */
137 if (prop < 0)
138 return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
139 fdt_getprop_by_offset(blob, prop, &name, NULL);
140 if (name)
141 puts(name);
142 prop = fdt_next_property_offset(blob, prop);
143 } while (1);
144 }
145
146 #define MAX_LEVEL 32 /* how deeply nested we will go */
147
148 /**
149 * List all subnodes in a node, one per line
150 *
151 * @param blob FDT blob
152 * @param node Node to display
153 * @return 0 if ok, or FDT_ERR... if not.
154 */
list_subnodes(const void * blob,int node)155 static int list_subnodes(const void *blob, int node)
156 {
157 int nextoffset; /* next node offset from libfdt */
158 uint32_t tag; /* current tag */
159 int level = 0; /* keep track of nesting level */
160 const char *pathp;
161 int depth = 1; /* the assumed depth of this node */
162
163 while (level >= 0) {
164 tag = fdt_next_tag(blob, node, &nextoffset);
165 switch (tag) {
166 case FDT_BEGIN_NODE:
167 pathp = fdt_get_name(blob, node, NULL);
168 if (level <= depth) {
169 if (pathp == NULL)
170 pathp = "/* NULL pointer error */";
171 if (*pathp == '\0')
172 pathp = "/"; /* root is nameless */
173 if (level == 1)
174 puts(pathp);
175 }
176 level++;
177 if (level >= MAX_LEVEL) {
178 printf("Nested too deep, aborting.\n");
179 return 1;
180 }
181 break;
182 case FDT_END_NODE:
183 level--;
184 if (level == 0)
185 level = -1; /* exit the loop */
186 break;
187 case FDT_END:
188 return 1;
189 case FDT_PROP:
190 break;
191 default:
192 if (level <= depth)
193 printf("Unknown tag 0x%08X\n", tag);
194 return 1;
195 }
196 node = nextoffset;
197 }
198 return 0;
199 }
200
201 /**
202 * Show the data for a given node (and perhaps property) according to the
203 * display option provided.
204 *
205 * @param blob FDT blob
206 * @param disp Display information / options
207 * @param node Node to display
208 * @param property Name of property to display, or NULL if none
209 * @return 0 if ok, -ve on error
210 */
show_data_for_item(const void * blob,struct display_info * disp,int node,const char * property)211 static int show_data_for_item(const void *blob, struct display_info *disp,
212 int node, const char *property)
213 {
214 const void *value = NULL;
215 int len, err = 0;
216
217 switch (disp->mode) {
218 case MODE_LIST_PROPS:
219 err = list_properties(blob, node);
220 break;
221
222 case MODE_LIST_SUBNODES:
223 err = list_subnodes(blob, node);
224 break;
225
226 default:
227 assert(property);
228 value = fdt_getprop(blob, node, property, &len);
229 if (value) {
230 if (show_data(disp, value, len))
231 err = -1;
232 else
233 printf("\n");
234 } else if (disp->default_val) {
235 puts(disp->default_val);
236 } else {
237 report_error(property, len);
238 err = -1;
239 }
240 break;
241 }
242
243 return err;
244 }
245
246 /**
247 * Run the main fdtget operation, given a filename and valid arguments
248 *
249 * @param disp Display information / options
250 * @param filename Filename of blob file
251 * @param arg List of arguments to process
252 * @param arg_count Number of arguments
253 * @return 0 if ok, -ve on error
254 */
do_fdtget(struct display_info * disp,const char * filename,char ** arg,int arg_count,int args_per_step)255 static int do_fdtget(struct display_info *disp, const char *filename,
256 char **arg, int arg_count, int args_per_step)
257 {
258 char *blob;
259 const char *prop;
260 int i, node;
261
262 blob = utilfdt_read(filename, NULL);
263 if (!blob)
264 return -1;
265
266 for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
267 node = fdt_path_offset(blob, arg[i]);
268 if (node < 0) {
269 if (disp->default_val) {
270 puts(disp->default_val);
271 continue;
272 } else {
273 report_error(arg[i], node);
274 free(blob);
275 return -1;
276 }
277 }
278 prop = args_per_step == 1 ? NULL : arg[i + 1];
279
280 if (show_data_for_item(blob, disp, node, prop)) {
281 free(blob);
282 return -1;
283 }
284 }
285
286 free(blob);
287
288 return 0;
289 }
290
291 /* Usage related data. */
292 static const char usage_synopsis[] =
293 "read values from device tree\n"
294 " fdtget <options> <dt file> [<node> <property>]...\n"
295 " fdtget -p <options> <dt file> [<node> ]...\n"
296 "\n"
297 "Each value is printed on a new line.\n"
298 USAGE_TYPE_MSG;
299 static const char usage_short_opts[] = "t:pld:" USAGE_COMMON_SHORT_OPTS;
300 static struct option const usage_long_opts[] = {
301 {"type", a_argument, NULL, 't'},
302 {"properties", no_argument, NULL, 'p'},
303 {"list", no_argument, NULL, 'l'},
304 {"default", a_argument, NULL, 'd'},
305 USAGE_COMMON_LONG_OPTS,
306 };
307 static const char * const usage_opts_help[] = {
308 "Type of data",
309 "List properties for each node",
310 "List subnodes for each node",
311 "Default value to display when the property is missing",
312 USAGE_COMMON_OPTS_HELP
313 };
314
main(int argc,char * argv[])315 int main(int argc, char *argv[])
316 {
317 int opt;
318 char *filename = NULL;
319 struct display_info disp;
320 int args_per_step = 2;
321
322 /* set defaults */
323 memset(&disp, '\0', sizeof(disp));
324 disp.size = -1;
325 disp.mode = MODE_SHOW_VALUE;
326 while ((opt = util_getopt_long()) != EOF) {
327 switch (opt) {
328 case_USAGE_COMMON_FLAGS
329
330 case 't':
331 if (utilfdt_decode_type(optarg, &disp.type,
332 &disp.size))
333 usage("invalid type string");
334 break;
335
336 case 'p':
337 disp.mode = MODE_LIST_PROPS;
338 args_per_step = 1;
339 break;
340
341 case 'l':
342 disp.mode = MODE_LIST_SUBNODES;
343 args_per_step = 1;
344 break;
345
346 case 'd':
347 disp.default_val = optarg;
348 break;
349 }
350 }
351
352 if (optind < argc)
353 filename = argv[optind++];
354 if (!filename)
355 usage("missing filename");
356
357 argv += optind;
358 argc -= optind;
359
360 /* Allow no arguments, and silently succeed */
361 if (!argc)
362 return 0;
363
364 /* Check for node, property arguments */
365 if (args_per_step == 2 && (argc % 2))
366 usage("must have an even number of arguments");
367
368 if (do_fdtget(&disp, filename, argv, argc, args_per_step))
369 return 1;
370 return 0;
371 }
372