/* vi: set sw=4 ts=4: */
/*
 * Mini du implementation for busybox
 *
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc.
 * Written by John Beppu <beppu@lineo.com>
 *
 * 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 <sys/types.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <string.h>
#include <errno.h>
#include "busybox.h"


#ifdef BB_FEATURE_HUMAN_READABLE
static unsigned long disp_hr = KILOBYTE;
#endif

typedef void (Display) (long, char *);

static int du_depth = 0;
static int count_hardlinks = 0;

static Display *print;

static void print_normal(long size, char *filename)
{
#ifdef BB_FEATURE_HUMAN_READABLE
	printf("%s\t%s\n", make_human_readable_str(size<<10, 1, disp_hr), filename);
#else
	printf("%ld\t%s\n", size, filename);
#endif
}

static void print_summary(long size, char *filename)
{
	if (du_depth == 1) {
		print_normal(size, filename);
	}
}

#define HASH_SIZE       311             /* Should be prime */
#define hash_inode(i)   ((i) % HASH_SIZE)

typedef struct ino_dev_hash_bucket_struct {
  struct ino_dev_hash_bucket_struct *next;
  ino_t ino;
  dev_t dev;
  char name[1];
} ino_dev_hashtable_bucket_t;

static ino_dev_hashtable_bucket_t *ino_dev_hashtable[HASH_SIZE];

/*
 * Return 1 if statbuf->st_ino && statbuf->st_dev are recorded in
 * `ino_dev_hashtable', else return 0
 *
 * If NAME is a non-NULL pointer to a character pointer, and there is
 * a match, then set *NAME to the value of the name slot in that
 * bucket.
 */
static int is_in_ino_dev_hashtable(const struct stat *statbuf, char **name)
{
	ino_dev_hashtable_bucket_t *bucket;

	bucket = ino_dev_hashtable[hash_inode(statbuf->st_ino)];
	while (bucket != NULL) {
	  if ((bucket->ino == statbuf->st_ino) &&
		  (bucket->dev == statbuf->st_dev))
	  {
		if (name) *name = bucket->name;
		return 1;
	  }
	  bucket = bucket->next;
	}
	return 0;
}

/* Add statbuf to statbuf hash table */
static void add_to_ino_dev_hashtable(const struct stat *statbuf, const char *name)
{
	int i;
	size_t s;
	ino_dev_hashtable_bucket_t *bucket;

	i = hash_inode(statbuf->st_ino);
	s = name ? strlen(name) : 0;
	bucket = xmalloc(sizeof(ino_dev_hashtable_bucket_t) + s);
	bucket->ino = statbuf->st_ino;
	bucket->dev = statbuf->st_dev;
	if (name)
		strcpy(bucket->name, name);
	else
		bucket->name[0] = '\0';
	bucket->next = ino_dev_hashtable[i];
	ino_dev_hashtable[i] = bucket;
}

/* Clear statbuf hash table */
static void reset_ino_dev_hashtable(void)
{
	int i;
	ino_dev_hashtable_bucket_t *bucket;

	for (i = 0; i < HASH_SIZE; i++) {
		while (ino_dev_hashtable[i] != NULL) {
			bucket = ino_dev_hashtable[i]->next;
			free(ino_dev_hashtable[i]);
			ino_dev_hashtable[i] = bucket;
		}
	}
}

/* tiny recursive du */
static long du(char *filename)
{
	struct stat statbuf;
	long sum;

	if ((lstat(filename, &statbuf)) != 0) {
		perror_msg("%s", filename);
		return 0;
	}

	du_depth++;
	sum = (statbuf.st_blocks >> 1);

	/* Don't add in stuff pointed to by symbolic links */
	if (S_ISLNK(statbuf.st_mode)) {
		sum = 0L;
		if (du_depth == 1)
			print(sum, filename);
	}
	if (S_ISDIR(statbuf.st_mode)) {
		DIR *dir;
		struct dirent *entry;
		char *newfile;

		dir = opendir(filename);
		if (!dir) {
			du_depth--;
			return 0;
		}

		newfile = last_char_is(filename, '/');
		if (newfile)
			*newfile = '\0';

		while ((entry = readdir(dir))) {
			char *name = entry->d_name;

			if ((strcmp(name, "..") == 0)
				|| (strcmp(name, ".") == 0)) {
				continue;
			}
			newfile = concat_path_file(filename, name);
			sum += du(newfile);
			free(newfile);
		}
		closedir(dir);
		print(sum, filename);
	}
	else if (statbuf.st_nlink > 1 && !count_hardlinks) {
		/* Add files with hard links only once */
		if (is_in_ino_dev_hashtable(&statbuf, NULL)) {
			sum = 0L;
			if (du_depth == 1)
				print(sum, filename);
		}
		else {
			add_to_ino_dev_hashtable(&statbuf, NULL);
		}
	}
	du_depth--;
	return sum;
}

int du_main(int argc, char **argv)
{
	int status = EXIT_SUCCESS;
	int i;
	int c;

	/* default behaviour */
	print = print_normal;

	/* parse argv[] */
	while ((c = getopt(argc, argv, "sl"
#ifdef BB_FEATURE_HUMAN_READABLE
"hm"
#endif
"k")) != EOF) {
			switch (c) {
			case 's':
					print = print_summary;
					break;
			case 'l':
					count_hardlinks = 1;
					break;
#ifdef BB_FEATURE_HUMAN_READABLE
			case 'h': disp_hr = 0;        break;
			case 'm': disp_hr = MEGABYTE; break;
#endif
			case 'k': break;
			default:
					show_usage();
			}
	}

	/* go through remaining args (if any) */
	if (optind >= argc) {
		if (du(".") == 0)
			status = EXIT_FAILURE;
	} else {
		long sum;

		for (i=optind; i < argc; i++) {
			if ((sum = du(argv[i])) == 0)
				status = EXIT_FAILURE;
			if(is_directory(argv[i], FALSE, NULL)==FALSE) {
				print_normal(sum, argv[i]);
			}
			reset_ino_dev_hashtable();
		}
	}

	return status;
}

/* $Id: du.c,v 1.49 2001/06/13 08:02:44 andersen Exp $ */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/