/*
 * 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.
 *
 * @(#) Copyright (c) 1989, 1993, 1994 The Regents of the University of California.  All rights reserved.
 * @(#)du.c     8.5 (Berkeley) 5/4/95
 * $FreeBSD: src/usr.bin/du/du.c,v 1.17.2.4 2002/12/12 16:29:39 trhodes Exp $
 */

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

#include <err.h>
#include <errno.h>
#include <fnmatch.h>
#include <fts.h>
#include <libutil.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#define HASHSIZE        256             /* power of 2 only */
#define HASHMASK        (HASHSIZE - 1)

#define STBLOCKS(statp) _stblocks(tflag, statp)

static SLIST_HEAD(ignhead, ignentry) ignores;
struct ignentry {
        char                    *mask;
        SLIST_ENTRY(ignentry)   next;
};

static int      linkchk(FTSENT *);
static void     usage(void);
void            prthumanval(int64_t);
void            ignoreadd(const char *);
void            ignoreclean(void);
int             ignorep(FTSENT *);

static char period[] = ".";

typedef long long       du_number_t;

static blkcnt_t
_stblocks(int tflag, struct stat *st)
{
        if (tflag)
                return (st->st_size + 511) / 512;
        else
                return st->st_blocks;
}

int
main(int argc, char **argv)
{
        FTS             *fts;
        FTSENT          *p;
        long            blocksize;
        du_number_t     savednumber = 0;
        int             ftsoptions;
        int             listall;
        int             depth;
        int             Hflag, Lflag, Pflag;
        int             aflag, sflag, dflag, cflag, hflag, tflag;
        int             ch, notused, rval;
        char            **save;

        Hflag = Lflag = Pflag = 0;
        aflag = sflag = dflag = cflag = hflag = tflag = 0;
        
        save = argv;
        ftsoptions = 0;
        depth = INT_MAX;
        SLIST_INIT(&ignores);
        
        while ((ch = getopt(argc, argv, "HI:LPastd:chkrx")) != -1)
                switch (ch) {
                        case 'H':
                                Hflag = 1;
                                break;
                        case 'I':
                                ignoreadd(optarg);
                                break;
                        case 'L':
                                if (Pflag)
                                        usage();
                                Lflag = 1;
                                break;
                        case 'P':
                                if (Lflag)
                                        usage();
                                Pflag = 1;
                                break;
                        case 'a':
                                aflag = 1;
                                break;
                        case 's':
                                sflag = 1;
                                break;
                        case 't':
                                tflag = 1;
                                break;
                        case 'd':
                                dflag = 1;
                                errno = 0;
                                depth = atoi(optarg);
                                if (errno == ERANGE || depth < 0) {
                                        warnx("invalid argument to option d: %s", optarg);
                                        usage();
                                }
                                break;
                        case 'c':
                                cflag = 1;
                                break;
                        case 'h':
                                if (setenv("BLOCKSIZE", "512", 1) == -1)
                                        warn("setenv: cannot set BLOCKSIZE=512");
                                hflag = 1;
                                break;
                        case 'k':
                                hflag = 0;
                                if (setenv("BLOCKSIZE", "1024", 1) == -1)
                                        warn("setenv: cannot set BLOCKSIZE=1024");
                                break;
                        case 'r':                /* Compatibility. */
                                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 + Lflag + Pflag > 1)
                usage();

        if (Hflag + Lflag + Pflag == 0)
                Pflag = 1;                      /* -P (physical) is default */

        if (Hflag)
                ftsoptions |= FTS_COMFOLLOW;

        if (Lflag)
                ftsoptions |= FTS_LOGICAL;

        if (Pflag)
                ftsoptions |= FTS_PHYSICAL;

        listall = 0;

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

        if (!*argv) {
                argv = save;
                argv[0] = period;
                argv[1] = NULL;
        }

        (void) getbsize(&notused, &blocksize);
        blocksize /= 512;

        rval = 0;
        
        if ((fts = fts_open(argv, ftsoptions, NULL)) == NULL)
                err(1, "fts_open");

        while ((p = fts_read(fts)) != NULL) {
                switch (p->fts_info) {
                        case FTS_D:                     /* Ignore. */
                                if (ignorep(p))
                                        fts_set(fts, p, FTS_SKIP);
                                break;
                        case FTS_DP:
                                if (ignorep(p))
                                        break;

                                if (p->fts_pointer == NULL) {
                                        p->fts_pointer = malloc(sizeof(du_number_t));
                                        *(du_number_t *)p->fts_pointer = 0;
                                }
                                *(du_number_t *)p->fts_pointer += STBLOCKS(p->fts_statp);

                                if (p->fts_parent->fts_pointer == NULL) {
                                        p->fts_parent->fts_pointer = malloc(sizeof(du_number_t));
                                        *(du_number_t *)p->fts_parent->fts_pointer = 0;
                                }
                                *(du_number_t *)p->fts_parent->fts_pointer += *(du_number_t *)p->fts_pointer += STBLOCKS(p->fts_statp);
                                
                                if (p->fts_level <= depth) {
                                        if (hflag) {
                                                (void) prthumanval(howmany(*(du_number_t *)p->fts_pointer, blocksize));
                                                (void) printf("\t%s\n", p->fts_path);
                                        } else {
                                        (void) printf("%lld\t%s\n",
                                            howmany(*(du_number_t *)p->fts_pointer, blocksize),
                                            p->fts_path);
                                        }
                                }
                                if (p->fts_pointer) {
                                        free(p->fts_pointer);
                                        p->fts_pointer = NULL;
                                }
                                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 (ignorep(p))
                                        break;

                                if (p->fts_statp->st_nlink > 1 && linkchk(p))
                                        break;
                                
                                if (listall || p->fts_level == 0) {
                                        if (hflag) {
                                                (void) prthumanval(howmany(STBLOCKS(p->fts_statp),
                                                        blocksize));
                                                (void) printf("\t%s\n", p->fts_path);
                                        } else {
                                                (void) printf("%lld\t%s\n",
                                                        howmany((long long)STBLOCKS(p->fts_statp), blocksize),
                                                        p->fts_path);
                                        }
                                }
                                if (p->fts_parent->fts_pointer == NULL) {
                                        p->fts_parent->fts_pointer = malloc(sizeof(du_number_t));
                                        *(du_number_t *)p->fts_parent->fts_pointer = 0;
                                }
                                *(du_number_t *)p->fts_parent->fts_pointer += STBLOCKS(p->fts_statp);
                }
                if (p->fts_parent->fts_pointer)
                        savednumber = *(du_number_t *)p->fts_parent->fts_pointer;
        }

        if (errno)
                err(1, "fts_read");

        fts_close(fts);

        if (cflag) {
                if (hflag) {
                        (void) prthumanval(howmany(savednumber, blocksize));
                        (void) printf("\ttotal\n");
                } else {
                        (void) printf("%lld\ttotal\n", howmany(savednumber, blocksize));
                }
        }

        ignoreclean();
        exit(rval);
}

static int
linkchk(FTSENT *p)
{
        struct links_entry {
                struct links_entry *next;
                struct links_entry *previous;
                int             links;
                dev_t           dev;
                ino_t           ino;
        };

        static const size_t links_hash_initial_size = 8192;
        static struct links_entry **buckets;
        static struct links_entry *free_list;
        static size_t number_buckets;
        static unsigned long number_entries;
        static char stop_allocating;
        struct links_entry *le, **new_buckets;
        struct stat *st;
        size_t i, new_size;
        int hash;

        st = p->fts_statp;

        /* If necessary, initialize the hash table. */
        if (buckets == NULL) {
                number_buckets = links_hash_initial_size;
                buckets = malloc(number_buckets * sizeof(buckets[0]));
                if (buckets == NULL)
                        errx(1, "No memory for hardlink detection");
                for (i = 0; i < number_buckets; i++)
                        buckets[i] = NULL;
        }

        /* If the hash table is getting too full, enlarge it. */
        if (number_entries > number_buckets * 10 && !stop_allocating) {
                new_size = number_buckets * 2;
                new_buckets = malloc(new_size * sizeof(struct links_entry *));

                /* Try releasing the free list to see if that helps. */
                if (new_buckets == NULL && free_list != NULL) {
                        while (free_list != NULL) {
                                le = free_list;
                                free_list = le->next;
                                free(le);
                        }
                        new_buckets = malloc(new_size * sizeof(new_buckets[0]));
                }

                if (new_buckets == NULL) {
                        stop_allocating = 1;
                        warnx("No more memory for tracking hard links");
                } else {
                        memset(new_buckets, 0, new_size * sizeof(struct links_entry *));
                        for (i = 0; i < number_buckets; i++) {
                                while (buckets[i] != NULL) {
                                        /* Remove entry from old bucket. */
                                        le = buckets[i];
                                        buckets[i] = le->next;
        
                                        /* Add entry to new bucket. */
                                        hash = (le->dev ^ le->ino) % new_size;
        
                                        if (new_buckets[hash] != NULL)
                                                new_buckets[hash]->previous = le;
                                        le->next = new_buckets[hash];
                                        le->previous = NULL;
                                        new_buckets[hash] = le;
                                }
                        }
                        free(buckets);
                        buckets = new_buckets;
                        number_buckets = new_size;
                }
        }

        /* Try to locate this entry in the hash table. */
        hash = ( st->st_dev ^ st->st_ino ) % number_buckets;
        for (le = buckets[hash]; le != NULL; le = le->next) {
                if (le->dev == st->st_dev && le->ino == st->st_ino) {
                        /*
                         * Save memory by releasing an entry when we've seen
                         * all of it's links.
                         */
                        if (--le->links <= 0) {
                                if (le->previous != NULL)
                                        le->previous->next = le->next;
                                if (le->next != NULL)
                                        le->next->previous = le->previous;
                                if (buckets[hash] == le)
                                        buckets[hash] = le->next;
                                number_entries--;
                                /* Recycle this node through the free list */
                                if (stop_allocating) {
                                        free(le);
                                } else {
                                        le->next = free_list;
                                        free_list = le;
                                }
                        }
                        return (1);
                }
        }

        if (stop_allocating)
                return (0);

        /* Add this entry to the links cache. */
        if (free_list != NULL) {
                /* Pull a node from the free list if we can. */
                le = free_list;
                free_list = le->next;
        } else
                /* Malloc one if we have to. */
                le = malloc(sizeof(struct links_entry));
        if (le == NULL) {
                stop_allocating = 1;
                warnx("No more memory for tracking hard links");
                return (0);
        }
        le->dev = st->st_dev;
        le->ino = st->st_ino;
        le->links = st->st_nlink - 1;
        number_entries++;
        le->next = buckets[hash];
        le->previous = NULL;
        if (buckets[hash] != NULL)
                buckets[hash]->previous = le;
        buckets[hash] = le;
        return (0);
}

void
prthumanval(int64_t bytes)
{
        char buf[sizeof("999M")];

        bytes *= DEV_BSIZE;

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

        (void) printf("%4s", buf);
}

static void
usage(void)
{
        (void)fprintf(stderr,
                "usage: du [-H | -L | -P] [-a | -s | -d depth] [-c] [-h | -k] [-x] [-I mask] [file ...]\n");
        exit(EX_USAGE);
}

void
ignoreadd(const char *mask)
{
        struct ignentry *ign;

        ign = calloc(1, sizeof(*ign));
        if (ign == NULL)
                errx(1, "cannot allocate memory");
        ign->mask = strdup(mask);
        if (ign->mask == NULL)
                errx(1, "cannot allocate memory");
        SLIST_INSERT_HEAD(&ignores, ign, next);
}

void
ignoreclean(void)
{
        struct ignentry *ign;
        
        while (!SLIST_EMPTY(&ignores)) {
                ign = SLIST_FIRST(&ignores);
                SLIST_REMOVE_HEAD(&ignores, next);
                free(ign->mask);
                free(ign);
        }
}

int
ignorep(FTSENT *ent)
{
        struct ignentry *ign;

        SLIST_FOREACH(ign, &ignores, next)
                if (fnmatch(ign->mask, ent->fts_name, 0) != FNM_NOMATCH)
                        return 1;
        return 0;
}