/*      $NetBSD: du.c,v 1.36 2012/03/11 11:23:20 shattered Exp $        */

/*
 * Copyright (c) 1989, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Newcomb.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1989, 1993, 1994\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)du.c        8.5 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: du.c,v 1.36 2012/03/11 11:23:20 shattered Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fts.h>
#include <inttypes.h>
#include <util.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

/* Count inodes or file size */
#define COUNT   (iflag ? 1 : p->fts_statp->st_blocks)

static int      linkchk(dev_t, ino_t);
static void     prstat(const char *, int64_t);
__dead static void      usage(void);

static int hflag, iflag;
static long blocksize;

int
main(int argc, char *argv[])
{
        FTS *fts;
        FTSENT *p;
        int64_t totalblocks;
        int ftsoptions, listfiles;
        int depth;
        int Hflag, Lflag, aflag, ch, cflag, dflag, gkmflag, nflag, rval, sflag;
        const char *noargv[2];

        Hflag = Lflag = aflag = cflag = dflag = gkmflag = nflag = sflag = 0;
        totalblocks = 0;
        ftsoptions = FTS_PHYSICAL;
        depth = INT_MAX;
        while ((ch = getopt(argc, argv, "HLPacd:ghikmnrsx")) != -1)
                switch (ch) {
                case 'H':
                        Hflag = 1;
                        Lflag = 0;
                        break;
                case 'L':
                        Lflag = 1;
                        Hflag = 0;
                        break;
                case 'P':
                        Hflag = Lflag = 0;
                        break;
                case 'a':
                        aflag = 1;
                        break;
                case 'c':
                        cflag = 1;
                        break;
                case 'd':
                        dflag = 1;
                        depth = atoi(optarg);
                        if (depth < 0 || depth > SHRT_MAX) {
                                warnx("invalid argument to option d: %s", 
                                        optarg);
                                usage();
                        }
                        break;
                case 'g':
                        blocksize = 1024 * 1024 * 1024;
                        gkmflag = 1;
                        break;
                case 'h':
                        hflag = 1;
                        break;
                case 'i':
                        iflag = 1;
                        break;
                case 'k':
                        blocksize = 1024;
                        gkmflag = 1;
                        break;
                case 'm':
                        blocksize = 1024 * 1024;
                        gkmflag = 1;
                        break; 
                case 'n':
                        nflag = 1;
                        break;
                case 'r':
                        break;
                case 's':
                        sflag = 1;
                        break;
                case 'x':
                        ftsoptions |= FTS_XDEV;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        /*
         * XXX
         * Because of the way that fts(3) works, logical walks will not count
         * the blocks actually used by symbolic links.  We rationalize this by
         * noting that users computing logical sizes are likely to do logical
         * copies, so not counting the links is correct.  The real reason is
         * that we'd have to re-implement the kernel's symbolic link traversing
         * algorithm to get this right.  If, for example, you have relative
         * symbolic links referencing other relative symbolic links, it gets
         * very nasty, very fast.  The bottom line is that it's documented in
         * the man page, so it's a feature.
         */
        if (Hflag)
                ftsoptions |= FTS_COMFOLLOW;
        if (Lflag) {
                ftsoptions &= ~FTS_PHYSICAL;
                ftsoptions |= FTS_LOGICAL;
        }

        listfiles = 0;
        if (aflag) {
                if (sflag || dflag)
                        usage();
                listfiles = 1;
        } else if (sflag) {
                if (dflag)
                        usage();
                depth = 0;
        }

        if (!*argv) {
                noargv[0] = ".";
                noargv[1] = NULL;
                argv = __UNCONST(noargv);
        }

        if (!gkmflag)
                (void)getbsize(NULL, &blocksize);
        blocksize /= 512;

        if ((fts = fts_open(argv, ftsoptions, NULL)) == NULL)
                err(1, "fts_open `%s'", *argv);

        for (rval = 0; (p = fts_read(fts)) != NULL;) {
                if (nflag) {
                        switch (p->fts_info) {
                        case FTS_NS:
                        case FTS_SLNONE:
                                /* nothing */
                                break;
                        default:
                                if (p->fts_statp->st_flags & UF_NODUMP) {
                                        fts_set(fts, p, FTS_SKIP);
                                        continue;
                                }
                        }
                }
                switch (p->fts_info) {
                case FTS_D:                     /* Ignore. */
                        break;
                case FTS_DP:
                        p->fts_parent->fts_number += 
                            p->fts_number += COUNT;
                        if (cflag)
                                totalblocks += COUNT;
                        /*
                         * If listing each directory, or not listing files
                         * or directories and this is post-order of the
                         * root of a traversal, display the total.
                         */
                        if (p->fts_level <= depth
                            || (!listfiles && !p->fts_level))
                                prstat(p->fts_path, p->fts_number);
                        break;
                case FTS_DC:                    /* Ignore. */
                        break;
                case FTS_DNR:                   /* Warn, continue. */
                case FTS_ERR:
                case FTS_NS:
                        warnx("%s: %s", p->fts_path, strerror(p->fts_errno));
                        rval = 1;
                        break;
                default:
                        if (p->fts_statp->st_nlink > 1 &&
                            linkchk(p->fts_statp->st_dev, p->fts_statp->st_ino))
                                break;
                        /*
                         * If listing each file, or a non-directory file was
                         * the root of a traversal, display the total.
                         */
                        if (listfiles || !p->fts_level)
                                prstat(p->fts_path, COUNT);
                        p->fts_parent->fts_number += COUNT;
                        if (cflag)
                                totalblocks += COUNT;
                }
        }
        if (errno)
                err(1, "fts_read");
        if (cflag)
                prstat("total", totalblocks);
        exit(rval);
}

static void
prstat(const char *fname, int64_t blocks)
{
        if (iflag) {
                (void)printf("%" PRId64 "\t%s\n", blocks, fname);
                return;
        }

        if (hflag) {
                char buf[5];
                int64_t sz = blocks * 512;

                humanize_number(buf, sizeof(buf), sz, "", HN_AUTOSCALE,
                    HN_B | HN_NOSPACE | HN_DECIMAL);

                (void)printf("%s\t%s\n", buf, fname);
        } else
                (void)printf("%" PRId64 "\t%s\n",
                    howmany(blocks, (int64_t)blocksize),
                    fname);
}

static int
linkchk(dev_t dev, ino_t ino)
{
        static struct entry {
                dev_t   dev;
                ino_t   ino;
        } *htable;
        static int htshift;  /* log(allocated size) */
        static int htmask;   /* allocated size - 1 */
        static int htused;   /* 2*number of insertions */
        static int sawzero;  /* Whether zero is in table or not */
        int h, h2;
        uint64_t tmp;
        /* this constant is (1<<64)/((1+sqrt(5))/2)
         * aka (word size)/(golden ratio)
         */
        const uint64_t HTCONST = 11400714819323198485ULL;
        const int HTBITS = CHAR_BIT * sizeof(tmp);

        /* Never store zero in hashtable */
        if (dev == 0 && ino == 0) {
                h = sawzero;
                sawzero = 1;
                return h;
        }

        /* Extend hash table if necessary, keep load under 0.5 */
        if (htused<<1 >= htmask) {
                struct entry *ohtable;

                if (!htable)
                        htshift = 10;   /* starting hashtable size */
                else
                        htshift++;   /* exponential hashtable growth */

                htmask  = (1 << htshift) - 1;
                htused = 0;

                ohtable = htable;
                htable = calloc(htmask+1, sizeof(*htable));
                if (!htable)
                        err(1, "calloc");

                /* populate newly allocated hashtable */
                if (ohtable) {
                        int i;
                        for (i = 0; i <= htmask>>1; i++)
                                if (ohtable[i].ino || ohtable[i].dev)
                                        linkchk(ohtable[i].dev, ohtable[i].ino);
                        free(ohtable);
                }
        }

        /* multiplicative hashing */
        tmp = dev;
        tmp <<= HTBITS>>1;
        tmp |=  ino;
        tmp *= HTCONST;
        h  = tmp >> (HTBITS - htshift);
        h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */

        /* open address hashtable search with double hash probing */
        while (htable[h].ino || htable[h].dev) {
                if ((htable[h].ino == ino) && (htable[h].dev == dev))
                        return 1;
                h = (h + h2) & htmask;
        }

        /* Insert the current entry into hashtable */
        htable[h].dev = dev;
        htable[h].ino = ino;
        htused++;
        return 0;
}

static void
usage(void)
{

        (void)fprintf(stderr,
                "usage: du [-H | -L | -P] [-a | -d depth | -s] [-cghikmnrx] [file ...]\n");
        exit(1);
}