/* 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 source tree.
 */
/* 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.
 */
//config:config DU
//config:       bool "du (default blocksize of 512 bytes)"
//config:       default y
//config:       help
//config:       du is used to report the amount of disk space used
//config:       for specified files.
//config:
//config:config FEATURE_DU_DEFAULT_BLOCKSIZE_1K
//config:       bool "Use a default blocksize of 1024 bytes (1K)"
//config:       default y
//config:       depends on DU
//config:       help
//config:       Use a blocksize of (1K) instead of the default 512b.

//applet:IF_DU(APPLET(du, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_DU) += du.o

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

//usage:#define du_trivial_usage
//usage:       "[-aHLdclsx" IF_FEATURE_HUMAN_READABLE("hm") "k] [FILE]..."
//usage:#define du_full_usage "\n\n"
//usage:       "Summarize disk space used for each FILE and/or directory\n"
//usage:     "\n        -a      Show file sizes too"
//usage:     "\n        -L      Follow all symlinks"
//usage:     "\n        -H      Follow symlinks on command line"
//usage:     "\n        -d N    Limit output to directories (and files with -a) of depth < N"
//usage:     "\n        -c      Show grand total"
//usage:     "\n        -l      Count sizes many times if hard linked"
//usage:     "\n        -s      Display only a total for each argument"
//usage:     "\n        -x      Skip directories on different filesystems"
//usage:        IF_FEATURE_HUMAN_READABLE(
//usage:     "\n        -h      Sizes in human readable format (e.g., 1K 243M 2G)"
//usage:     "\n        -m      Sizes in megabytes"
//usage:        )
//usage:     "\n        -k      Sizes in kilobytes" IF_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(" (default)")
//usage:        IF_NOT_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(
//usage:     "\n                Default unit is 512 bytes"
//usage:        )
//usage:
//usage:#define du_example_usage
//usage:       "$ du\n"
//usage:       "16      ./CVS\n"
//usage:       "12      ./kernel-patches/CVS\n"
//usage:       "80      ./kernel-patches\n"
//usage:       "12      ./tests/CVS\n"
//usage:       "36      ./tests\n"
//usage:       "12      ./scripts/CVS\n"
//usage:       "16      ./scripts\n"
//usage:       "12      ./docs/CVS\n"
//usage:       "104     ./docs\n"
//usage:       "2417    .\n"

#include "libbb.h"
#include "common_bufsiz.h"

enum {
        OPT_a_files_too    = (1 << 0),
        OPT_H_follow_links = (1 << 1),
        OPT_k_kbytes       = (1 << 2),
        OPT_L_follow_links = (1 << 3),
        OPT_s_total_norecurse = (1 << 4),
        OPT_x_one_FS       = (1 << 5),
        OPT_d_maxdepth     = (1 << 6),
        OPT_l_hardlinks    = (1 << 7),
        OPT_c_total        = (1 << 8),
        OPT_h_for_humans   = (1 << 9),
        OPT_m_mbytes       = (1 << 10),
};

struct globals {
#if ENABLE_FEATURE_HUMAN_READABLE
        unsigned long disp_unit;
#else
        unsigned disp_k;
#endif
        int max_print_depth;
        bool status;
        int slink_depth;
        int du_depth;
        dev_t dir_dev;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { setup_common_bufsiz(); } while (0)


static void print(unsigned long long size, const char *filename)
{
        /* TODO - May not want to defer error checking here. */
#if ENABLE_FEATURE_HUMAN_READABLE
# if ENABLE_DESKTOP
        /* ~30 bytes of code for extra comtat:
         * coreutils' du rounds sizes up:
         * for example,  1025k file is shown as "2" by du -m.
         * We round to nearest if human-readable [too hard to fix],
         * else (fixed scale such as -m), we round up. To that end,
         * add yet another half of the unit before displaying:
         */
        if (G.disp_unit)
                size += (G.disp_unit-1) / (unsigned)(512 * 2);
# endif
        printf("%s\t%s\n",
                        /* size x 512 / G.disp_unit.
                         * If G.disp_unit == 0, show one fractional
                         * and use suffixes
                         */
                        make_human_readable_str(size, 512, G.disp_unit),
                        filename);
#else
        if (G.disp_k) {
                size++;
                size >>= 1;
        }
        printf("%llu\t%s\n", size, filename);
#endif
}

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

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

        if (option_mask32 & OPT_x_one_FS) {
                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) {
                                /* Convert -H to -L */
                                G.slink_depth = INT_MAX;
                        }
                }
        }

        if (!(option_mask32 & OPT_l_hardlinks)
         && statbuf.st_nlink > 1
        ) {
                /* 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;
                }

                while ((entry = readdir(dir))) {
                        newfile = concat_subpath_file(filename, entry->d_name);
                        if (newfile == NULL)
                                continue;
                        ++G.du_depth;
                        sum += du(newfile);
                        --G.du_depth;
                        free(newfile);
                }
                closedir(dir);
        } else {
                if (!(option_mask32 & OPT_a_files_too) && G.du_depth != 0)
                        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 long total;
        int slink_depth_save;
        unsigned opt;

        INIT_G();

#if ENABLE_FEATURE_HUMAN_READABLE
        IF_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_unit = 1024;)
        IF_NOT_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_unit = 512;)
        if (getenv("POSIXLY_CORRECT"))  /* TODO - a new libbb function? */
                G.disp_unit = 512;
#else
        IF_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_k = 1;)
        /* IF_NOT_FEATURE_DU_DEFAULT_BLOCKSIZE_1K(G.disp_k = 0;) - G is pre-zeroed */
#endif
        G.max_print_depth = INT_MAX;

        /* 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 = getopt32(argv, "^"
                        "aHkLsxd:+lchm"
                        "\0" "h-km:k-hm:m-hk:H-L:L-H:s-d:d-s",
                        &G.max_print_depth
        );
        argv += optind;
        if (opt & OPT_h_for_humans) {
                G.disp_unit = 0;
        }
        if (opt & OPT_m_mbytes) {
                G.disp_unit = 1024*1024;
        }
        if (opt & OPT_k_kbytes) {
                G.disp_unit = 1024;
        }
#else
        opt = getopt32(argv, "^"
                        "aHkLsxd:+lc"
                        "\0" "H-L:L-H:s-d:d-s",
                        &G.max_print_depth
        );
        argv += optind;
#if !ENABLE_FEATURE_DU_DEFAULT_BLOCKSIZE_1K
        if (opt & OPT_k_kbytes) {
                G.disp_k = 1;
        }
#endif
#endif
        if (opt & OPT_H_follow_links) {
                G.slink_depth = 1;
        }
        if (opt & OPT_L_follow_links) {
                G.slink_depth = INT_MAX;
        }
        if (opt & OPT_s_total_norecurse) {
                G.max_print_depth = 0;
        }

        /* 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);
                /* otherwise du /dir /dir won't show /dir twice: */
                reset_ino_dev_hashtable();
                G.slink_depth = slink_depth_save;
        } while (*++argv);

        if (opt & OPT_c_total)
                print(total, "total");

        fflush_stdout_and_exit(G.status);
}