/*
   * 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
  ", 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:
  ");
  
  	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
  ", value_size);
  				return -1;
  			}
  		}
  
  		ptr = value + upto;
  		if (disp->type == 's') {
  			memcpy(ptr, *arg, len);
  			if (disp->verbose)
  				fprintf(stderr, "\tstring: '%s'
  ", 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
  ",
  					disp->size == 1 ? "byte" :
  					disp->size == 2 ? "short" : "int",
  					ival);
  			}
  		}
  	}
  	*value_len = upto;
  	*valuep = value;
  	if (disp->verbose)
  		fprintf(stderr, "Value size %d
  ", 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
  "
  	"
  "
  	"The command line arguments are joined together into a single value.
  "
  	"
  "
  	"Usage:
  "
  	"	fdtput <options> <dt file> <node> <property> [<value>...]
  "
  	"	fdtput -c <options> <dt file> [<node>...]
  "
  	"Options:
  "
  	"\t-c\t\tCreate nodes if they don't already exist
  "
  	"\t-p\t\tAutomatically create nodes as needed for the node path
  "
  	"\t-t <type>\tType of data
  "
  	"\t-v\t\tVerbose: display each value decoded from command line
  "
  	"\t-h\t\tPrint this help
  
  "
  	USAGE_TYPE_MSG;
  
  static void usage(const char *msg)
  {
  	if (msg)
  		fprintf(stderr, "Error: %s
  
  ", 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;
  }