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 */
18 enum oper_type {
19 OPER_WRITE_PROP, /* Write a property in a node */
20 OPER_CREATE_NODE, /* Create a new node */
21 };
22
23 struct 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 */
39 static 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 */
56 static 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
120 static 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 */
150 static 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 */
192 static 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
221 static 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
261 static 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
277 static 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
286 int 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
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