scripts/dtc/fdtput.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
0004  */
0005
0006 #include <assert.h>
0007 #include <ctype.h>
0008 #include <getopt.h>
0009 #include <stdio.h>
0010 #include <stdlib.h>
0011 #include <string.h>
0012
0013 #include <libfdt.h>
0014
0015 #include "util.h"
0016
0017 /* These are the operations we support */
0018 enum oper_type {
0019     OPER_WRITE_PROP,        /* Write a property in a node */
0020     OPER_CREATE_NODE,       /* Create a new node */
0021 };
0022
0023 struct display_info {
0024     enum oper_type oper;    /* operation to perform */
0025     int type;       /* data type (s/i/u/x or 0 for default) */
0026     int size;       /* data size (1/2/4) */
0027     int verbose;        /* verbose output */
0028     int auto_path;      /* automatically create all path components */
0029 };
0030
0031
0032 /**
0033  * Report an error with a particular node.
0034  *
0035  * @param name      Node name to report error on
0036  * @param namelen   Length of node name, or -1 to use entire string
0037  * @param err       Error number to report (-FDT_ERR_...)
0038  */
0039 static void report_error(const char *name, int namelen, int err)
0040 {
0041     if (namelen == -1)
0042         namelen = strlen(name);
0043     fprintf(stderr, "Error at '%1.*s': %s\n", namelen, name,
0044         fdt_strerror(err));
0045 }
0046
0047 /**
0048  * Encode a series of arguments in a property value.
0049  *
0050  * @param disp      Display information / options
0051  * @param arg       List of arguments from command line
0052  * @param arg_count Number of arguments (may be 0)
0053  * @param valuep    Returns buffer containing value
0054  * @param *value_len    Returns length of value encoded
0055  */
0056 static int encode_value(struct display_info *disp, char **arg, int arg_count,
0057             char **valuep, int *value_len)
0058 {
0059     char *value = NULL; /* holding area for value */
0060     int value_size = 0; /* size of holding area */
0061     char *ptr;      /* pointer to current value position */
0062     int len;        /* length of this cell/string/byte */
0063     int ival;
0064     int upto;   /* the number of bytes we have written to buf */
0065     char fmt[3];
0066
0067     upto = 0;
0068
0069     if (disp->verbose)
0070         fprintf(stderr, "Decoding value:\n");
0071
0072     fmt[0] = '%';
0073     fmt[1] = disp->type ? disp->type : 'd';
0074     fmt[2] = '\0';
0075     for (; arg_count > 0; arg++, arg_count--, upto += len) {
0076         /* assume integer unless told otherwise */
0077         if (disp->type == 's')
0078             len = strlen(*arg) + 1;
0079         else
0080             len = disp->size == -1 ? 4 : disp->size;
0081
0082         /* enlarge our value buffer by a suitable margin if needed */
0083         if (upto + len > value_size) {
0084             value_size = (upto + len) + 500;
0085             value = realloc(value, value_size);
0086             if (!value) {
0087                 fprintf(stderr, "Out of mmory: cannot alloc "
0088                     "%d bytes\n", value_size);
0089                 return -1;
0090             }
0091         }
0092
0093         ptr = value + upto;
0094         if (disp->type == 's') {
0095             memcpy(ptr, *arg, len);
0096             if (disp->verbose)
0097                 fprintf(stderr, "\tstring: '%s'\n", ptr);
0098         } else {
0099             int *iptr = (int *)ptr;
0100             sscanf(*arg, fmt, &ival);
0101             if (len == 4)
0102                 *iptr = cpu_to_fdt32(ival);
0103             else
0104                 *ptr = (uint8_t)ival;
0105             if (disp->verbose) {
0106                 fprintf(stderr, "\t%s: %d\n",
0107                     disp->size == 1 ? "byte" :
0108                     disp->size == 2 ? "short" : "int",
0109                     ival);
0110             }
0111         }
0112     }
0113     *value_len = upto;
0114     *valuep = value;
0115     if (disp->verbose)
0116         fprintf(stderr, "Value size %d\n", upto);
0117     return 0;
0118 }
0119
0120 static int store_key_value(void *blob, const char *node_name,
0121         const char *property, const char *buf, int len)
0122 {
0123     int node;
0124     int err;
0125
0126     node = fdt_path_offset(blob, node_name);
0127     if (node < 0) {
0128         report_error(node_name, -1, node);
0129         return -1;
0130     }
0131
0132     err = fdt_setprop(blob, node, property, buf, len);
0133     if (err) {
0134         report_error(property, -1, err);
0135         return -1;
0136     }
0137     return 0;
0138 }
0139
0140 /**
0141  * Create paths as needed for all components of a path
0142  *
0143  * Any components of the path that do not exist are created. Errors are
0144  * reported.
0145  *
0146  * @param blob      FDT blob to write into
0147  * @param in_path   Path to process
0148  * @return 0 if ok, -1 on error
0149  */
0150 static int create_paths(void *blob, const char *in_path)
0151 {
0152     const char *path = in_path;
0153     const char *sep;
0154     int node, offset = 0;
0155
0156     /* skip leading '/' */
0157     while (*path == '/')
0158         path++;
0159
0160     for (sep = path; *sep; path = sep + 1, offset = node) {
0161         /* equivalent to strchrnul(), but it requires _GNU_SOURCE */
0162         sep = strchr(path, '/');
0163         if (!sep)
0164             sep = path + strlen(path);
0165
0166         node = fdt_subnode_offset_namelen(blob, offset, path,
0167                 sep - path);
0168         if (node == -FDT_ERR_NOTFOUND) {
0169             node = fdt_add_subnode_namelen(blob, offset, path,
0170                                sep - path);
0171         }
0172         if (node < 0) {
0173             report_error(path, sep - path, node);
0174             return -1;
0175         }
0176     }
0177
0178     return 0;
0179 }
0180
0181 /**
0182  * Create a new node in the fdt.
0183  *
0184  * This will overwrite the node_name string. Any error is reported.
0185  *
0186  * TODO: Perhaps create fdt_path_offset_namelen() so we don't need to do this.
0187  *
0188  * @param blob      FDT blob to write into
0189  * @param node_name Name of node to create
0190  * @return new node offset if found, or -1 on failure
0191  */
0192 static int create_node(void *blob, const char *node_name)
0193 {
0194     int node = 0;
0195     char *p;
0196
0197     p = strrchr(node_name, '/');
0198     if (!p) {
0199         report_error(node_name, -1, -FDT_ERR_BADPATH);
0200         return -1;
0201     }
0202     *p = '\0';
0203
0204     if (p > node_name) {
0205         node = fdt_path_offset(blob, node_name);
0206         if (node < 0) {
0207             report_error(node_name, -1, node);
0208             return -1;
0209         }
0210     }
0211
0212     node = fdt_add_subnode(blob, node, p + 1);
0213     if (node < 0) {
0214         report_error(p + 1, -1, node);
0215         return -1;
0216     }
0217
0218     return 0;
0219 }
0220
0221 static int do_fdtput(struct display_info *disp, const char *filename,
0222             char **arg, int arg_count)
0223 {
0224     char *value;
0225     char *blob;
0226     int len, ret = 0;
0227
0228     blob = utilfdt_read(filename);
0229     if (!blob)
0230         return -1;
0231
0232     switch (disp->oper) {
0233     case OPER_WRITE_PROP:
0234         /*
0235          * Convert the arguments into a single binary value, then
0236          * store them into the property.
0237          */
0238         assert(arg_count >= 2);
0239         if (disp->auto_path && create_paths(blob, *arg))
0240             return -1;
0241         if (encode_value(disp, arg + 2, arg_count - 2, &value, &len) ||
0242             store_key_value(blob, *arg, arg[1], value, len))
0243             ret = -1;
0244         break;
0245     case OPER_CREATE_NODE:
0246         for (; ret >= 0 && arg_count--; arg++) {
0247             if (disp->auto_path)
0248                 ret = create_paths(blob, *arg);
0249             else
0250                 ret = create_node(blob, *arg);
0251         }
0252         break;
0253     }
0254     if (ret >= 0)
0255         ret = utilfdt_write(filename, blob);
0256
0257     free(blob);
0258     return ret;
0259 }
0260
0261 static const char *usage_msg =
0262     "fdtput - write a property value to a device tree\n"
0263     "\n"
0264     "The command line arguments are joined together into a single value.\n"
0265     "\n"
0266     "Usage:\n"
0267     "   fdtput <options> <dt file> <node> <property> [<value>...]\n"
0268     "   fdtput -c <options> <dt file> [<node>...]\n"
0269     "Options:\n"
0270     "\t-c\t\tCreate nodes if they don't already exist\n"
0271     "\t-p\t\tAutomatically create nodes as needed for the node path\n"
0272     "\t-t <type>\tType of data\n"
0273     "\t-v\t\tVerbose: display each value decoded from command line\n"
0274     "\t-h\t\tPrint this help\n\n"
0275     USAGE_TYPE_MSG;
0276
0277 static void usage(const char *msg)
0278 {
0279     if (msg)
0280         fprintf(stderr, "Error: %s\n\n", msg);
0281
0282     fprintf(stderr, "%s", usage_msg);
0283     exit(2);
0284 }
0285
0286 int main(int argc, char *argv[])
0287 {
0288     struct display_info disp;
0289     char *filename = NULL;
0290
0291     memset(&disp, '\0', sizeof(disp));
0292     disp.size = -1;
0293     disp.oper = OPER_WRITE_PROP;
0294     for (;;) {
0295         int c = getopt(argc, argv, "chpt:v");
0296         if (c == -1)
0297             break;
0298
0299         /*
0300          * TODO: add options to:
0301          * - delete property
0302          * - delete node (optionally recursively)
0303          * - rename node
0304          * - pack fdt before writing
0305          * - set amount of free space when writing
0306          * - expand fdt if value doesn't fit
0307          */
0308         switch (c) {
0309         case 'c':
0310             disp.oper = OPER_CREATE_NODE;
0311             break;
0312         case 'h':
0313         case '?':
0314             usage(NULL);
0315         case 'p':
0316             disp.auto_path = 1;
0317             break;
0318         case 't':
0319             if (utilfdt_decode_type(optarg, &disp.type,
0320                     &disp.size))
0321                 usage("Invalid type string");
0322             break;
0323
0324         case 'v':
0325             disp.verbose = 1;
0326             break;
0327         }
0328     }
0329
0330     if (optind < argc)
0331         filename = argv[optind++];
0332     if (!filename)
0333         usage("Missing filename");
0334
0335     argv += optind;
0336     argc -= optind;
0337
0338     if (disp.oper == OPER_WRITE_PROP) {
0339         if (argc < 1)
0340             usage("Missing node");
0341         if (argc < 2)
0342             usage("Missing property");
0343     }
0344
0345     if (do_fdtput(&disp, filename, argv, argc))
0346         return 1;
0347     return 0;
0348 }