/* vi: set sw=4 ts=4: */
/*
 * Mini du implementation for busybox
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc. and John Beppu
 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
 * Copyright (C) 2002  Edward Betts <edward@debian.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* BB_AUDIT SUSv3 compliant (unless default blocksize set to 1k) */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/du.html */

/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
 *
 * Mostly rewritten for SUSv3 compliance and to fix bugs/defects.
 * 1) Added support for SUSv3 -a, -H, -L, gnu -c, and (busybox) -d options.
 *    The -d option allows setting of max depth (similar to gnu --max-depth).
 * 2) Fixed incorrect size calculations for links and directories, especially
 *    when errors occurred.  Calculates sizes should now match gnu du output.
 * 3) Added error checking of output.
 * 4) Fixed busybox bug #1284 involving long overflow with human_readable.
 */

#include "libbb.h"

struct globals {
#if ENABLE_FEATURE_HUMAN_READABLE
        unsigned long disp_hr;
#else
        unsigned disp_k;
#endif

        int max_print_depth;
        nlink_t count_hardlinks;

        bool status;
        bool one_file_system;
        int print_files;
        int slink_depth;
        int du_depth;
        dev_t dir_dev;
};
#define G (*(struct globals*)&bb_common_bufsiz1)


static void print(unsigned long size, const char *filename)
{
        /* TODO - May not want to defer error checking here. */
#if ENABLE_FEATURE_HUMAN_READABLE
        printf("%s\t%s\n", make_human_readable_str(size, 512, G.disp_hr),
                        filename);
#else
        if (G.disp_k) {
                size++;
                size >>= 1;
        }
        printf("%ld\t%s\n", size, filename);
#endif
}

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

        if (lstat(filename, &statbuf) != 0) {
                bb_simple_perror_msg(filename);
                G.status = EXIT_FAILURE;
                return 0;
        }

        if (G.one_file_system) {
                if (G.du_depth == 0) {
                        G.dir_dev = statbuf.st_dev;
                } else if (G.dir_dev != statbuf.st_dev) {
                        return 0;
                }
        }

        sum = statbuf.st_blocks;

        if (S_ISLNK(statbuf.st_mode)) {
                if (G.slink_depth > G.du_depth) {       /* -H or -L */
                        if (stat(filename, &statbuf) != 0) {
                                bb_simple_perror_msg(filename);
                                G.status = EXIT_FAILURE;
                                return 0;
                        }
                        sum = statbuf.st_blocks;
                        if (G.slink_depth == 1) {
                                G.slink_depth = INT_MAX;        /* Convert -H to -L. */
                        }
                }
        }

        if (statbuf.st_nlink > G.count_hardlinks) {
                /* Add files/directories with links only once */
                if (is_in_ino_dev_hashtable(&statbuf)) {
                        return 0;
                }
                add_to_ino_dev_hashtable(&statbuf, NULL);
        }

        if (S_ISDIR(statbuf.st_mode)) {
                DIR *dir;
                struct dirent *entry;
                char *newfile;

                dir = warn_opendir(filename);
                if (!dir) {
                        G.status = EXIT_FAILURE;
                        return sum;
                }

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

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

                        newfile = concat_subpath_file(filename, name);
                        if (newfile == NULL)
                                continue;
                        ++G.du_depth;
                        sum += du(newfile);
                        --G.du_depth;
                        free(newfile);
                }
                closedir(dir);
        } else if (G.du_depth > G.print_files) {
                return sum;
        }
        if (G.du_depth <= G.max_print_depth) {
                print(sum, filename);
        }
        return sum;
}

int du_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int du_main(int argc UNUSED_PARAM, char **argv)
{
        unsigned long total;
        int slink_depth_save;
        bool print_final_total;
        unsigned opt;

#if ENABLE_FEATURE_HUMAN_READABLE
        USE_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_hr = 1024;)
        SKIP_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_hr = 512;)
        if (getenv("POSIXLY_CORRECT"))  /* TODO - a new libbb function? */
                G.disp_hr = 512;
#else
        USE_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_k = 1;)
        /* SKIP_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_k = 0;) - G is pre-zeroed */
#endif
        G.max_print_depth = INT_MAX;
        G.count_hardlinks = 1;

        /* Note: SUSv3 specifies that -a and -s options cannot be used together
         * in strictly conforming applications.  However, it also says that some
         * du implementations may produce output when -a and -s are used together.
         * gnu du exits with an error code in this case.  We choose to simply
         * ignore -a.  This is consistent with -s being equivalent to -d 0.
         */
#if ENABLE_FEATURE_HUMAN_READABLE
        opt_complementary = "h-km:k-hm:m-hk:H-L:L-H:s-d:d-s:d+";
        opt = getopt32(argv, "aHkLsx" "d:" "lc" "hm", &G.max_print_depth);
        argv += optind;
        if (opt & (1 << 9)) {
                /* -h opt */
                G.disp_hr = 0;
        }
        if (opt & (1 << 10)) {
                /* -m opt */
                G.disp_hr = 1024*1024;
        }
        if (opt & (1 << 2)) {
                /* -k opt */
                G.disp_hr = 1024;
        }
#else
        opt_complementary = "H-L:L-H:s-d:d-s:d+";
        opt = getopt32(argv, "aHkLsx" "d:" "lc", &G.max_print_depth);
        argv += optind;
#if !ENABLE_FEATURE_DU_DEFAULT_BLOCKSIZE_1K
        if (opt & (1 << 2)) {
                /* -k opt */
                G.disp_k = 1;
        }
#endif
#endif
        if (opt & (1 << 0)) {
                /* -a opt */
                G.print_files = INT_MAX;
        }
        if (opt & (1 << 1)) {
                /* -H opt */
                G.slink_depth = 1;
        }
        if (opt & (1 << 3)) {
                /* -L opt */
                G.slink_depth = INT_MAX;
        }
        if (opt & (1 << 4)) {
                /* -s opt */
                G.max_print_depth = 0;
        }
        G.one_file_system = opt & (1 << 5); /* -x opt */
        if (opt & (1 << 7)) {
                /* -l opt */
                G.count_hardlinks = MAXINT(nlink_t);
        }
        print_final_total = opt & (1 << 8); /* -c opt */

        /* go through remaining args (if any) */
        if (!*argv) {
                *--argv = (char*)".";
                if (G.slink_depth == 1) {
                        G.slink_depth = 0;
                }
        }

        slink_depth_save = G.slink_depth;
        total = 0;
        do {
                total += du(*argv);
                G.slink_depth = slink_depth_save;
        } while (*++argv);

        if (ENABLE_FEATURE_CLEAN_UP)
                reset_ino_dev_hashtable();
        if (print_final_total)
                print(total, "total");

        fflush_stdout_and_exit(G.status);
}