/*
 * 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 */
};


/**
 * Report an error with a particular node.
 *
 * @param name          Node name to report error on
 * @param namelen       Length of node name, or -1 to use entire string
 * @param err           Error number to report (-FDT_ERR_...)
 */
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));
}

/**
 * Encode a series of arguments in a property value.
 *
 * @param disp          Display information / options
 * @param arg           List of arguments from command line
 * @param arg_count     Number of arguments (may be 0)
 * @param valuep        Returns buffer containing value
 * @param *value_len    Returns length of value encoded
 */
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;
}

/**
 * Create paths as needed for all components of a path
 *
 * Any components of the path that do not exist are created. Errors are
 * reported.
 *
 * @param blob          FDT blob to write into
 * @param in_path       Path to process
 * @return 0 if ok, -1 on error
 */
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;
}

/**
 * Create a new node in the fdt.
 *
 * This will overwrite the node_name string. Any error is reported.
 *
 * TODO: Perhaps create fdt_path_offset_namelen() so we don't need to do this.
 *
 * @param blob          FDT blob to write into
 * @param node_name     Name of node to create
 * @return new node offset if found, or -1 on failure
 */
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;
}