fdtput.c

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/*
 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <assert.h>
#include <ctype.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <libfdt.h>

#include "util.h"

/* These are the operations we support */
enum oper_type {
    OPER_WRITE_PROP,        /* Write a property in a node */
    OPER_CREATE_NODE,       /* Create a new node */
};

struct display_info {
    enum oper_type oper;    /* operation to perform */
    int type;       /* data type (s/i/u/x or 0 for default) */
    int size;       /* data size (1/2/4) */
    int verbose;        /* verbose output */
    int auto_path;      /* automatically create all path components */
};


static void report_error(const char *name, int namelen, int err)
{
    if (namelen == -1)
        namelen = strlen(name);
    fprintf(stderr, "Error at '%1.*s': %s\n", namelen, name,
        fdt_strerror(err));
}

static int encode_value(struct display_info *disp, char **arg, int arg_count,
            char **valuep, int *value_len)
{
    char *value = NULL; /* holding area for value */
    int value_size = 0; /* size of holding area */
    char *ptr;      /* pointer to current value position */
    int len;        /* length of this cell/string/byte */
    int ival;
    int upto;   /* the number of bytes we have written to buf */
    char fmt[3];

    upto = 0;

    if (disp->verbose)
        fprintf(stderr, "Decoding value:\n");

    fmt[0] = '%';
    fmt[1] = disp->type ? disp->type : 'd';
    fmt[2] = '\0';
    for (; arg_count > 0; arg++, arg_count--, upto += len) {
        /* assume integer unless told otherwise */
        if (disp->type == 's')
            len = strlen(*arg) + 1;
        else
            len = disp->size == -1 ? 4 : disp->size;

        /* enlarge our value buffer by a suitable margin if needed */
        if (upto + len > value_size) {
            value_size = (upto + len) + 500;
            value = realloc(value, value_size);
            if (!value) {
                fprintf(stderr, "Out of mmory: cannot alloc "
                    "%d bytes\n", value_size);
                return -1;
            }
        }

        ptr = value + upto;
        if (disp->type == 's') {
            memcpy(ptr, *arg, len);
            if (disp->verbose)
                fprintf(stderr, "\tstring: '%s'\n", ptr);
        } else {
            int *iptr = (int *)ptr;
            sscanf(*arg, fmt, &ival);
            if (len == 4)
                *iptr = cpu_to_fdt32(ival);
            else
                *ptr = (uint8_t)ival;
            if (disp->verbose) {
                fprintf(stderr, "\t%s: %d\n",
                    disp->size == 1 ? "byte" :
                    disp->size == 2 ? "short" : "int",
                    ival);
            }
        }
    }
    *value_len = upto;
    *valuep = value;
    if (disp->verbose)
        fprintf(stderr, "Value size %d\n", upto);
    return 0;
}

static int store_key_value(void *blob, const char *node_name,
        const char *property, const char *buf, int len)
{
    int node;
    int err;

    node = fdt_path_offset(blob, node_name);
    if (node < 0) {
        report_error(node_name, -1, node);
        return -1;
    }

    err = fdt_setprop(blob, node, property, buf, len);
    if (err) {
        report_error(property, -1, err);
        return -1;
    }
    return 0;
}

static int create_paths(void *blob, const char *in_path)
{
    const char *path = in_path;
    const char *sep;
    int node, offset = 0;

    /* skip leading '/' */
    while (*path == '/')
        path++;

    for (sep = path; *sep; path = sep + 1, offset = node) {
        /* equivalent to strchrnul(), but it requires _GNU_SOURCE */
        sep = strchr(path, '/');
        if (!sep)
            sep = path + strlen(path);

        node = fdt_subnode_offset_namelen(blob, offset, path,
                sep - path);
        if (node == -FDT_ERR_NOTFOUND) {
            node = fdt_add_subnode_namelen(blob, offset, path,
                               sep - path);
        }
        if (node < 0) {
            report_error(path, sep - path, node);
            return -1;
        }
    }

    return 0;
}

static int create_node(void *blob, const char *node_name)
{
    int node = 0;
    char *p;

    p = strrchr(node_name, '/');
    if (!p) {
        report_error(node_name, -1, -FDT_ERR_BADPATH);
        return -1;
    }
    *p = '\0';

    if (p > node_name) {
        node = fdt_path_offset(blob, node_name);
        if (node < 0) {
            report_error(node_name, -1, node);
            return -1;
        }
    }

    node = fdt_add_subnode(blob, node, p + 1);
    if (node < 0) {
        report_error(p + 1, -1, node);
        return -1;
    }

    return 0;
}

static int do_fdtput(struct display_info *disp, const char *filename,
            char **arg, int arg_count)
{
    char *value;
    char *blob;
    int len, ret = 0;

    blob = utilfdt_read(filename);
    if (!blob)
        return -1;

    switch (disp->oper) {
    case OPER_WRITE_PROP:
        /*
         * Convert the arguments into a single binary value, then
         * store them into the property.
         */
        assert(arg_count >= 2);
        if (disp->auto_path && create_paths(blob, *arg))
            return -1;
        if (encode_value(disp, arg + 2, arg_count - 2, &value, &len) ||
            store_key_value(blob, *arg, arg[1], value, len))
            ret = -1;
        break;
    case OPER_CREATE_NODE:
        for (; ret >= 0 && arg_count--; arg++) {
            if (disp->auto_path)
                ret = create_paths(blob, *arg);
            else
                ret = create_node(blob, *arg);
        }
        break;
    }
    if (ret >= 0)
        ret = utilfdt_write(filename, blob);

    free(blob);
    return ret;
}

static const char *usage_msg =
    "fdtput - write a property value to a device tree\n"
    "\n"
    "The command line arguments are joined together into a single value.\n"
    "\n"
    "Usage:\n"
    "   fdtput <options> <dt file> <node> <property> [<value>...]\n"
    "   fdtput -c <options> <dt file> [<node>...]\n"
    "Options:\n"
    "\t-c\t\tCreate nodes if they don't already exist\n"
    "\t-p\t\tAutomatically create nodes as needed for the node path\n"
    "\t-t <type>\tType of data\n"
    "\t-v\t\tVerbose: display each value decoded from command line\n"
    "\t-h\t\tPrint this help\n\n"
    USAGE_TYPE_MSG;

static void usage(const char *msg)
{
    if (msg)
        fprintf(stderr, "Error: %s\n\n", msg);

    fprintf(stderr, "%s", usage_msg);
    exit(2);
}

int main(int argc, char *argv[])
{
    struct display_info disp;
    char *filename = NULL;

    memset(&disp, '\0', sizeof(disp));
    disp.size = -1;
    disp.oper = OPER_WRITE_PROP;
    for (;;) {
        int c = getopt(argc, argv, "chpt:v");
        if (c == -1)
            break;

        /*
         * TODO: add options to:
         * - delete property
         * - delete node (optionally recursively)
         * - rename node
         * - pack fdt before writing
         * - set amount of free space when writing
         * - expand fdt if value doesn't fit
         */
        switch (c) {
        case 'c':
            disp.oper = OPER_CREATE_NODE;
            break;
        case 'h':
        case '?':
            usage(NULL);
        case 'p':
            disp.auto_path = 1;
            break;
        case 't':
            if (utilfdt_decode_type(optarg, &disp.type,
                    &disp.size))
                usage("Invalid type string");
            break;

        case 'v':
            disp.verbose = 1;
            break;
        }
    }

    if (optind < argc)
        filename = argv[optind++];
    if (!filename)
        usage("Missing filename");

    argv += optind;
    argc -= optind;

    if (disp.oper == OPER_WRITE_PROP) {
        if (argc < 1)
            usage("Missing node");
        if (argc < 2)
            usage("Missing property");
    }

    if (do_fdtput(&disp, filename, argv, argc))
        return 1;
    return 0;
}