/* vi: set sw=4 ts=4: */
/*
 *  mini dpkg implementation for busybox.
 *  this is not meant as a replacement for dpkg
 *
 *  written by glenn mcgrath with the help of others
 *  copyright (c) 2001 by glenn mcgrath
 *
 *  parts of the version comparison code is plucked from the real dpkg
 *  application which is licensed GPLv2 and
 *  copyright (c) 1995 Ian Jackson <ian@chiark.greenend.org.uk>
 *
 *  started life as a busybox implementation of udpkg
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
/*
 * known difference between busybox dpkg and the official dpkg that i don't
 * consider important, its worth keeping a note of differences anyway, just to
 * make it easier to maintain.
 *  - the first value for the confflile: field isn't placed on a new line.
 *  - when installing a package the status: field is placed at the end of the
 *      section, rather than just after the package: field.
 *
 * bugs that need to be fixed
 *  - (unknown, please let me know when you find any)
 */
//config:config DPKG
//config:       bool "dpkg (43 kb)"
//config:       default y
//config:       select FEATURE_SEAMLESS_GZ
//config:       help
//config:       dpkg is a medium-level tool to install, build, remove and manage
//config:       Debian packages.
//config:
//config:       This implementation of dpkg has a number of limitations,
//config:       you should use the official dpkg if possible.

//applet:IF_DPKG(APPLET(dpkg, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_DPKG) += dpkg.o

//usage:#define dpkg_trivial_usage
//usage:       "[-ilCPru] [-F OPT] PACKAGE"
//usage:#define dpkg_full_usage "\n\n"
//usage:       "Install, remove and manage Debian packages\n"
//usage:        IF_LONG_OPTS(
//usage:     "\n        -i,--install    Install the package"
//usage:     "\n        -l,--list       List of installed packages"
//usage:     "\n        --configure     Configure an unpackaged package"
//usage:     "\n        -P,--purge      Purge all files of a package"
//usage:     "\n        -r,--remove     Remove all but the configuration files for a package"
//usage:     "\n        --unpack        Unpack a package, but don't configure it"
//usage:     "\n        --force-depends Ignore dependency problems"
//usage:     "\n        --force-confnew Overwrite existing config files when installing"
//usage:     "\n        --force-confold Keep old config files when installing"
//usage:        )
//usage:        IF_NOT_LONG_OPTS(
//usage:     "\n        -i              Install the package"
//usage:     "\n        -l              List of installed packages"
//usage:     "\n        -C              Configure an unpackaged package"
//usage:     "\n        -P              Purge all files of a package"
//usage:     "\n        -r              Remove all but the configuration files for a package"
//usage:     "\n        -u              Unpack a package, but don't configure it"
//usage:     "\n        -F depends      Ignore dependency problems"
//usage:     "\n        -F confnew      Overwrite existing config files when installing"
//usage:     "\n        -F confold      Keep old config files when installing"
//usage:        )

#include "libbb.h"
#include <fnmatch.h>
#include "bb_archive.h"

/* note: if you vary hash_prime sizes be aware,
 * 1) tweaking these will have a big effect on how much memory this program uses.
 * 2) for computational efficiency these hash tables should be at least 20%
 *    larger than the maximum number of elements stored in it.
 * 3) all _hash_prime's must be a prime number or chaos is assured, if your looking
 *    for a prime, try http://www.utm.edu/research/primes/lists/small/10000.txt
 * 4) if you go bigger than 15 bits you may get into trouble (untested) as its
 *    sometimes cast to an unsigned, if you go to 16 bit you will overlap
 *    int's and chaos is assured, 16381 is the max prime for 14 bit field
 */

/* NAME_HASH_PRIME, Stores package names and versions,
 * I estimate it should be at least 50% bigger than PACKAGE_HASH_PRIME,
 * as there a lot of duplicate version numbers */
#define NAME_HASH_PRIME 16381

/* PACKAGE_HASH_PRIME, Maximum number of unique packages,
 * It must not be smaller than STATUS_HASH_PRIME,
 * Currently only packages from status_hashtable are stored in here, but in
 * future this may be used to store packages not only from a status file,
 * but an available_hashtable, and even multiple packages files.
 * Package can be stored more than once if they have different versions.
 * e.g. The same package may have different versions in the status file
 *      and available file */
#define PACKAGE_HASH_PRIME 10007
typedef struct edge_s {
        unsigned operator:4; /* was:3 */
        unsigned type:4;
        unsigned name:16; /* was:14 */
        unsigned version:16; /* was:14 */
} edge_t;

typedef struct common_node_s {
        unsigned name:16; /* was:14 */
        unsigned version:16; /* was:14 */
        unsigned num_of_edges:16; /* was:14 */
        edge_t **edge;
} common_node_t;

/* Currently it doesn't store packages that have state-status of not-installed
 * So it only really has to be the size of the maximum number of packages
 * likely to be installed at any one time, so there is a bit of leeway here */
#define STATUS_HASH_PRIME 8191
typedef struct status_node_s {
        unsigned package:16; /* was:14 */       /* has to fit PACKAGE_HASH_PRIME */
        unsigned status:16; /* was:14 */        /* has to fit STATUS_HASH_PRIME */
} status_node_t;


/* Globals */
struct globals {
        char          *name_hashtable[NAME_HASH_PRIME + 1];
        common_node_t *package_hashtable[PACKAGE_HASH_PRIME + 1];
        status_node_t *status_hashtable[STATUS_HASH_PRIME + 1];
};
#define G (*ptr_to_globals)
#define name_hashtable    (G.name_hashtable   )
#define package_hashtable (G.package_hashtable)
#define status_hashtable  (G.status_hashtable )
#define INIT_G() do { \
        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)


/* Even numbers are for 'extras', like ored dependencies or null */
enum edge_type_e {
        EDGE_NULL = 0,
        EDGE_PRE_DEPENDS = 1,
        EDGE_OR_PRE_DEPENDS = 2,
        EDGE_DEPENDS = 3,
        EDGE_OR_DEPENDS = 4,
        EDGE_REPLACES = 5,
        EDGE_PROVIDES = 7,
        EDGE_CONFLICTS = 9,
        EDGE_SUGGESTS = 11,
        EDGE_RECOMMENDS = 13,
        EDGE_ENHANCES = 15
};
enum operator_e {
        VER_NULL = 0,
        VER_EQUAL = 1,
        VER_LESS = 2,
        VER_LESS_EQUAL = 3,
        VER_MORE = 4,
        VER_MORE_EQUAL = 5,
        VER_ANY = 6
};

typedef struct deb_file_s {
        char *control_file;
        char *filename;
        unsigned package:16; /* was:14 */
} deb_file_t;


static void make_hash(const char *key, unsigned *start, unsigned *decrement, const int hash_prime)
{
        unsigned long hash_num = key[0];
        int len = strlen(key);
        int i;

        /* Maybe i should have uses a "proper" hashing algorithm here instead
         * of making one up myself, seems to be working ok though. */
        for (i = 1; i < len; i++) {
                /* shifts the ascii based value and adds it to previous value
                 * shift amount is mod 24 because long int is 32 bit and data
                 * to be shifted is 8, don't want to shift data to where it has
                 * no effect */
                hash_num += (key[i] + key[i-1]) << ((key[i] * i) % 24);
        }
        *start = (unsigned) hash_num % hash_prime;
        *decrement = (unsigned) 1 + (hash_num % (hash_prime - 1));
}

/* this adds the key to the hash table */
static int search_name_hashtable(const char *key)
{
        unsigned probe_address;
        unsigned probe_decrement;

        make_hash(key, &probe_address, &probe_decrement, NAME_HASH_PRIME);
        while (name_hashtable[probe_address] != NULL) {
                if (strcmp(name_hashtable[probe_address], key) == 0) {
                        return probe_address;
                }
                probe_address -= probe_decrement;
                if ((int)probe_address < 0) {
                        probe_address += NAME_HASH_PRIME;
                }
        }
        name_hashtable[probe_address] = xstrdup(key);
        return probe_address;
}

/* this DOESN'T add the key to the hashtable
 * TODO make it consistent with search_name_hashtable
 */
static unsigned search_status_hashtable(const char *key)
{
        unsigned probe_address;
        unsigned probe_decrement;

        make_hash(key, &probe_address, &probe_decrement, STATUS_HASH_PRIME);
        while (status_hashtable[probe_address] != NULL) {
                if (strcmp(key, name_hashtable[package_hashtable[status_hashtable[probe_address]->package]->name]) == 0) {
                        break;
                }
                probe_address -= probe_decrement;
                if ((int)probe_address < 0) {
                        probe_address += STATUS_HASH_PRIME;
                }
        }
        return probe_address;
}

static int order(char x)
{
        return (x == '~' ? -1
                : x == '\0' ? 0
                : isdigit(x) ? 0
                : isalpha(x) ? x
                : (unsigned char)x + 256
        );
}

/* This code is taken from dpkg and modified slightly to work with busybox */
static int version_compare_part(const char *val, const char *ref)
{
        if (!val) val = "";
        if (!ref) ref = "";

        while (*val || *ref) {
                int first_diff;

                while ((*val && !isdigit(*val)) || (*ref && !isdigit(*ref))) {
                        int vc = order(*val);
                        int rc = order(*ref);
                        if (vc != rc)
                                return vc - rc;
                        val++;
                        ref++;
                }

                while (*val == '0')
                        val++;
                while (*ref == '0')
                        ref++;

                first_diff = 0;
                while (isdigit(*val) && isdigit(*ref)) {
                        if (first_diff == 0)
                                first_diff = *val - *ref;
                        val++;
                        ref++;
                }
                if (isdigit(*val))
                        return 1;
                if (isdigit(*ref))
                        return -1;
                if (first_diff)
                        return first_diff;
        }
        return 0;
}

/* if ver1 < ver2 return -1,
 * if ver1 = ver2 return 0,
 * if ver1 > ver2 return 1,
 */
static int version_compare(const unsigned ver1, const unsigned ver2)
{
        char *ch_ver1 = name_hashtable[ver1];
        char *ch_ver2 = name_hashtable[ver2];
        unsigned epoch1 = 0, epoch2 = 0;
        char *colon;
        char *deb_ver1, *deb_ver2;
        char *upstream_ver1;
        char *upstream_ver2;
        int result;

        /* Compare epoch */
        colon = strchr(ch_ver1, ':');
        if (colon) {
                epoch1 = atoi(ch_ver1);
                ch_ver1 = colon + 1;
        }
        colon = strchr(ch_ver2, ':');
        if (colon) {
                epoch2 = atoi(ch_ver2);
                ch_ver2 = colon + 1;
        }
        if (epoch1 < epoch2) {
                return -1;
        }
        if (epoch1 > epoch2) {
                return 1;
        }

        /* Compare upstream version */
        upstream_ver1 = xstrdup(ch_ver1);
        upstream_ver2 = xstrdup(ch_ver2);

        /* Chop off debian version, and store for later use */
        deb_ver1 = strrchr(upstream_ver1, '-');
        deb_ver2 = strrchr(upstream_ver2, '-');
        if (deb_ver1) {
                *deb_ver1++ = '\0';
        }
        if (deb_ver2) {
                *deb_ver2++ = '\0';
        }
        result = version_compare_part(upstream_ver1, upstream_ver2);
        if (result == 0) {
                /* Compare debian versions */
                result = version_compare_part(deb_ver1, deb_ver2);
        }

        free(upstream_ver1);
        free(upstream_ver2);
        return result;
}

static int test_version(const unsigned version1, const unsigned version2, const unsigned operator)
{
        const int version_result = version_compare(version1, version2);
        switch (operator) {
        case VER_ANY:
                return TRUE;
        case VER_EQUAL:
                return (version_result == 0);
        case VER_LESS:
                return (version_result < 0);
        case VER_LESS_EQUAL:
                return (version_result <= 0);
        case VER_MORE:
                return (version_result > 0);
        case VER_MORE_EQUAL:
                return (version_result >= 0);
        }
        return FALSE;
}

static int search_package_hashtable(const unsigned name, const unsigned version, const unsigned operator)
{
        unsigned probe_address;
        unsigned probe_decrement;

        make_hash(name_hashtable[name], &probe_address, &probe_decrement, PACKAGE_HASH_PRIME);
        while (package_hashtable[probe_address] != NULL) {
                if (package_hashtable[probe_address]->name == name) {
                        if (operator == VER_ANY) {
                                return probe_address;
                        }
                        if (test_version(package_hashtable[probe_address]->version, version, operator)) {
                                return probe_address;
                        }
                }
                probe_address -= probe_decrement;
                if ((int)probe_address < 0) {
                        probe_address += PACKAGE_HASH_PRIME;
                }
        }
        return probe_address;
}

/*
 * This function searches through the entire package_hashtable looking
 * for a package which provides "needle". It returns the index into
 * the package_hashtable for the providing package.
 *
 * needle is the index into name_hashtable of the package we are
 * looking for.
 *
 * start_at is the index in the package_hashtable to start looking
 * at. If start_at is -1 then start at the beginning. This is to allow
 * for repeated searches since more than one package might provide
 * needle.
 *
 * FIXME: I don't think this is very efficient, but I thought I'd keep
 * it simple for now until it proves to be a problem.
 */
static int search_for_provides(int needle, int start_at)
{
        int i, j;
        common_node_t *p;
        for (i = start_at + 1; i < PACKAGE_HASH_PRIME; i++) {
                p = package_hashtable[i];
                if (p == NULL)
                        continue;
                for (j = 0; j < p->num_of_edges; j++)
                        if (p->edge[j]->type == EDGE_PROVIDES && p->edge[j]->name == needle)
                                return i;
        }
        return -1;
}

/*
 * Add an edge to a node
 */
static void add_edge_to_node(common_node_t *node, edge_t *edge)
{
        node->edge = xrealloc_vector(node->edge, 2, node->num_of_edges);
        node->edge[node->num_of_edges++] = edge;
}

/*
 * Create one new node and one new edge for every dependency.
 *
 * Dependencies which contain multiple alternatives are represented as
 * an EDGE_OR_PRE_DEPENDS or EDGE_OR_DEPENDS node, followed by a
 * number of EDGE_PRE_DEPENDS or EDGE_DEPENDS nodes. The name field of
 * the OR edge contains the full dependency string while the version
 * field contains the number of EDGE nodes which follow as part of
 * this alternative.
 */
static void add_split_dependencies(common_node_t *parent_node, const char *whole_line, unsigned edge_type)
{
        char *line = xstrdup(whole_line);
        char *line2;
        char *line_ptr1 = NULL;
        char *line_ptr2 = NULL;
        char *field;
        char *field2;
        char *version;
        edge_t *edge;
        edge_t *or_edge;
        int offset_ch;

        field = strtok_r(line, ",", &line_ptr1);
        do {
                /* skip leading spaces */
                field += strspn(field, " ");
                line2 = xstrdup(field);
                field2 = strtok_r(line2, "|", &line_ptr2);
                or_edge = NULL;
                if ((edge_type == EDGE_DEPENDS || edge_type == EDGE_PRE_DEPENDS)
                 && (strcmp(field, field2) != 0)
                ) {
                        or_edge = xzalloc(sizeof(edge_t));
                        or_edge->type = edge_type + 1;
                        or_edge->name = search_name_hashtable(field);
                        //or_edge->version = 0; // tracks the number of alternatives
                        add_edge_to_node(parent_node, or_edge);
                }

                do {
                        edge = xmalloc(sizeof(edge_t));
                        edge->type = edge_type;

                        /* Skip any extra leading spaces */
                        field2 += strspn(field2, " ");

                        /* Get dependency version info */
                        version = strchr(field2, '(');
                        if (version == NULL) {
                                edge->operator = VER_ANY;
                                /* Get the versions hash number, adding it if the number isn't already in there */
                                edge->version = search_name_hashtable("ANY");
                        } else {
                                /* Skip leading ' ' or '(' */
                                version += strspn(version, " (");
                                /* Calculate length of any operator characters */
                                offset_ch = strspn(version, "<=>");
                                /* Determine operator */
                                if (offset_ch > 0) {
                                        if (strncmp(version, "=", offset_ch) == 0) {
                                                edge->operator = VER_EQUAL;
                                        } else if (strncmp(version, "<<", offset_ch) == 0) {
                                                edge->operator = VER_LESS;
                                        } else if (strncmp(version, "<=", offset_ch) == 0) {
                                                edge->operator = VER_LESS_EQUAL;
                                        } else if (strncmp(version, ">>", offset_ch) == 0) {
                                                edge->operator = VER_MORE;
                                        } else if (strncmp(version, ">=", offset_ch) == 0) {
                                                edge->operator = VER_MORE_EQUAL;
                                        } else {
                                                bb_simple_error_msg_and_die("illegal operator");
                                        }
                                }
                                /* skip to start of version numbers */
                                version += offset_ch;
                                version += strspn(version, " ");

                                /* Truncate version at trailing ' ' or ')' */
                                version[strcspn(version, " )")] = '\0';
                                /* Get the versions hash number, adding it if the number isn't already in there */
                                edge->version = search_name_hashtable(version);
                        }

                        /* Get the dependency name */
                        field2[strcspn(field2, " (")] = '\0';
                        edge->name = search_name_hashtable(field2);

                        if (or_edge)
                                or_edge->version++;

                        add_edge_to_node(parent_node, edge);
                        field2 = strtok_r(NULL, "|", &line_ptr2);
                } while (field2 != NULL);

                free(line2);
                field = strtok_r(NULL, ",", &line_ptr1);
        } while (field != NULL);

        free(line);
}

static void free_package(common_node_t *node)
{
        unsigned i;
        if (node) {
                for (i = 0; i < node->num_of_edges; i++) {
                        free(node->edge[i]);
                }
                free(node->edge);
                free(node);
        }
}

/*
 * Gets the next package field from package_buffer, separated into the field name
 * and field value, it returns the int offset to the first character of the next field
 */
static int read_package_field(const char *package_buffer, char **field_name, char **field_value)
{
        int offset_name_start = 0;
        int offset_name_end = 0;
        int offset_value_start = 0;
        int offset_value_end = 0;
        int offset = 0;
        int next_offset;
        int name_length;
        int value_length;
        int exit_flag = FALSE;

        if (package_buffer == NULL) {
                *field_name = NULL;
                *field_value = NULL;
                return -1;
        }
        while (1) {
                next_offset = offset + 1;
                switch (package_buffer[offset]) {
                        case '\0':
                                exit_flag = TRUE;
                                break;
                        case ':':
                                if (offset_name_end == 0) {
                                        offset_name_end = offset;
                                        offset_value_start = next_offset;
                                }
                                /* TODO: Name might still have trailing spaces if ':' isn't
                                 * immediately after name */
                                break;
                        case '\n':
                                /* TODO: The char next_offset may be out of bounds */
                                if (package_buffer[next_offset] != ' ') {
                                        exit_flag = TRUE;
                                        break;
                                }
                        case '\t':
                        case ' ':
                                /* increment the value start point if its a just filler */
                                if (offset_name_start == offset) {
                                        offset_name_start++;
                                }
                                if (offset_value_start == offset) {
                                        offset_value_start++;
                                }
                                break;
                }
                if (exit_flag) {
                        /* Check that the names are valid */
                        offset_value_end = offset;
                        name_length = offset_name_end - offset_name_start;
                        value_length = offset_value_end - offset_value_start;
                        if (name_length == 0) {
                                break;
                        }
                        if ((name_length > 0) && (value_length > 0)) {
                                break;
                        }

                        /* If not valid, start fresh with next field */
                        exit_flag = FALSE;
                        offset_name_start = offset + 1;
                        offset_name_end = 0;
                        offset_value_start = offset + 1;
                        offset_value_end = offset + 1;
                        offset++;
                }
                offset++;
        }
        *field_name = NULL;
        if (name_length) {
                *field_name = xstrndup(&package_buffer[offset_name_start], name_length);
        }
        *field_value = NULL;
        if (value_length > 0) {
                *field_value = xstrndup(&package_buffer[offset_value_start], value_length);
        }
        return next_offset;
}

static unsigned fill_package_struct(char *control_buffer)
{
        static const char field_names[] ALIGN1 =
                "Package\0""Version\0"
                "Pre-Depends\0""Depends\0""Replaces\0""Provides\0"
                "Conflicts\0""Suggests\0""Recommends\0""Enhances\0";

        common_node_t *new_node = xzalloc(sizeof(common_node_t));
        char *field_name;
        char *field_value;
        int field_start = 0;
        int num = -1;
        int buffer_length = strlen(control_buffer);

        new_node->version = search_name_hashtable("unknown");
        while (field_start < buffer_length) {
                unsigned field_num;

                field_start += read_package_field(&control_buffer[field_start],
                                &field_name, &field_value);

                if (field_name == NULL) {
                        goto fill_package_struct_cleanup;
                }

                field_num = index_in_strings(field_names, field_name);
                switch (field_num) {
                case 0: /* Package */
                        new_node->name = search_name_hashtable(field_value);
                        break;
                case 1: /* Version */
                        new_node->version = search_name_hashtable(field_value);
                        break;
                case 2: /* Pre-Depends */
                        add_split_dependencies(new_node, field_value, EDGE_PRE_DEPENDS);
                        break;
                case 3: /* Depends */
                        add_split_dependencies(new_node, field_value, EDGE_DEPENDS);
                        break;
                case 4: /* Replaces */
                        add_split_dependencies(new_node, field_value, EDGE_REPLACES);
                        break;
                case 5: /* Provides */
                        add_split_dependencies(new_node, field_value, EDGE_PROVIDES);
                        break;
                case 6: /* Conflicts */
                        add_split_dependencies(new_node, field_value, EDGE_CONFLICTS);
                        break;
                case 7: /* Suggests */
                        add_split_dependencies(new_node, field_value, EDGE_SUGGESTS);
                        break;
                case 8: /* Recommends */
                        add_split_dependencies(new_node, field_value, EDGE_RECOMMENDS);
                        break;
                case 9: /* Enhances */
                        add_split_dependencies(new_node, field_value, EDGE_ENHANCES);
                        break;
                }
 fill_package_struct_cleanup:
                free(field_name);
                free(field_value);
        }

        if (new_node->version == search_name_hashtable("unknown")) {
                free_package(new_node);
                return -1;
        }
        num = search_package_hashtable(new_node->name, new_node->version, VER_EQUAL);
        free_package(package_hashtable[num]);
        package_hashtable[num] = new_node;
        return num;
}

/* if num = 1, it returns the want status, 2 returns flag, 3 returns status */
static unsigned get_status(const unsigned status_node, const int num)
{
        char *status_string = name_hashtable[status_hashtable[status_node]->status];
        char *state_sub_string;
        unsigned state_sub_num;
        int len;
        int i;

        /* set tmp_string to point to the start of the word number */
        for (i = 1; i < num; i++) {
                /* skip past a word */
                status_string += strcspn(status_string, " ");
                /* skip past the separating spaces */
                status_string += strspn(status_string, " ");
        }
        len = strcspn(status_string, " \n");
        state_sub_string = xstrndup(status_string, len);
        state_sub_num = search_name_hashtable(state_sub_string);
        free(state_sub_string);
        return state_sub_num;
}

static void set_status(const unsigned status_node_num, const char *new_value, const int position)
{
        const unsigned new_value_num = search_name_hashtable(new_value);
        unsigned want = get_status(status_node_num, 1);
        unsigned flag = get_status(status_node_num, 2);
        unsigned status = get_status(status_node_num, 3);
        char *new_status;

        switch (position) {
                case 1:
                        want = new_value_num;
                        break;
                case 2:
                        flag = new_value_num;
                        break;
                case 3:
                        status = new_value_num;
                        break;
                default:
                        bb_simple_error_msg_and_die("DEBUG ONLY: this shouldnt happen");
        }

        new_status = xasprintf("%s %s %s", name_hashtable[want], name_hashtable[flag], name_hashtable[status]);
        status_hashtable[status_node_num]->status = search_name_hashtable(new_status);
        free(new_status);
}

static const char *describe_status(int status_num)
{
        int status_want, status_state;
        if (status_hashtable[status_num] == NULL || status_hashtable[status_num]->status == 0)
                return "is not installed or flagged to be installed";

        status_want = get_status(status_num, 1);
        status_state = get_status(status_num, 3);

        if (status_state == search_name_hashtable("installed")) {
                if (status_want == search_name_hashtable("install"))
                        return "is installed";
                if (status_want == search_name_hashtable("deinstall"))
                        return "is marked to be removed";
                if (status_want == search_name_hashtable("purge"))
                        return "is marked to be purged";
        }
        if (status_want == search_name_hashtable("unknown"))
                return "is in an indeterminate state";
        if (status_want == search_name_hashtable("install"))
                return "is marked to be installed";

        return "is not installed or flagged to be installed";
}

static void index_status_file(const char *filename)
{
        FILE *status_file;
        char *control_buffer;
        char *status_line;
        status_node_t *status_node = NULL;
        unsigned status_num;

        status_file = xfopen_for_read(filename);
        while ((control_buffer = xmalloc_fgetline_str(status_file, "\n\n")) != NULL) {
                const unsigned package_num = fill_package_struct(control_buffer);
                if (package_num != -1) {
                        status_node = xmalloc(sizeof(status_node_t));
                        /* fill_package_struct doesn't handle the status field */
                        status_line = strstr(control_buffer, "Status:");
                        if (status_line != NULL) {
                                status_line += 7;
                                status_line += strspn(status_line, " \n\t");
                                status_line = xstrndup(status_line, strcspn(status_line, "\n"));
                                status_node->status = search_name_hashtable(status_line);
                                free(status_line);
                        }
                        status_node->package = package_num;
                        status_num = search_status_hashtable(name_hashtable[package_hashtable[status_node->package]->name]);
                        status_hashtable[status_num] = status_node;
                }
                free(control_buffer);
        }
        fclose(status_file);
}

static void write_buffer_no_status(FILE *new_status_file, const char *control_buffer)
{
        char *name;
        char *value;
        int start = 0;
        while (1) {
                start += read_package_field(&control_buffer[start], &name, &value);
                if (name == NULL) {
                        break;
                }
                if (strcmp(name, "Status") != 0) {
                        fprintf(new_status_file, "%s: %s\n", name, value);
                }
        }
}

/* This could do with a cleanup */
static void write_status_file(deb_file_t **deb_file)
{
        FILE *old_status_file = xfopen_for_read("/var/lib/dpkg/status");
        FILE *new_status_file = xfopen_for_write("/var/lib/dpkg/status.udeb");
        char *package_name;
        char *status_from_file;
        char *control_buffer = NULL;
        char *tmp_string;
        int status_num;
        int field_start = 0;
        int write_flag;
        int i = 0;

        /* Update previously known packages */
        while ((control_buffer = xmalloc_fgetline_str(old_status_file, "\n\n")) != NULL) {
                tmp_string = strstr(control_buffer, "Package:");
                if (tmp_string == NULL) {
                        continue;
                }

                tmp_string += 8;
                tmp_string += strspn(tmp_string, " \n\t");
                package_name = xstrndup(tmp_string, strcspn(tmp_string, "\n"));
                write_flag = FALSE;
                tmp_string = strstr(control_buffer, "Status:");
                if (tmp_string != NULL) {
                        /* Separate the status value from the control buffer */
                        tmp_string += 7;
                        tmp_string += strspn(tmp_string, " \n\t");
                        status_from_file = xstrndup(tmp_string, strcspn(tmp_string, "\n"));
                } else {
                        status_from_file = NULL;
                }

                /* Find this package in the status hashtable */
                status_num = search_status_hashtable(package_name);
                if (status_hashtable[status_num] != NULL) {
                        const char *status_from_hashtable = name_hashtable[status_hashtable[status_num]->status];
                        if (strcmp(status_from_file, status_from_hashtable) != 0) {
                                /* New status isn't exactly the same as old status */
                                const int state_status = get_status(status_num, 3);
                                if ((strcmp("installed", name_hashtable[state_status]) == 0)
                                 || (strcmp("unpacked", name_hashtable[state_status]) == 0)
                                ) {
                                        /* We need to add the control file from the package */
                                        i = 0;
                                        while (deb_file[i] != NULL) {
                                                if (strcmp(package_name, name_hashtable[package_hashtable[deb_file[i]->package]->name]) == 0) {
                                                        /* Write a status file entry with a modified status */
                                                        /* remove trailing \n's */
                                                        write_buffer_no_status(new_status_file, deb_file[i]->control_file);
                                                        set_status(status_num, "ok", 2);
                                                        fprintf(new_status_file, "Status: %s\n\n",
                                                                        name_hashtable[status_hashtable[status_num]->status]);
                                                        write_flag = TRUE;
                                                        break;
                                                }
                                                i++;
                                        }
                                        /* This is temperary, debugging only */
                                        if (deb_file[i] == NULL) {
                                                bb_error_msg_and_die("ALERT: cannot find a control file, "
                                                        "your status file may be broken, status may be "
                                                        "incorrect for %s", package_name);
                                        }
                                }
                                else if (strcmp("not-installed", name_hashtable[state_status]) == 0) {
                                        /* Only write the Package, Status, Priority and Section lines */
                                        fprintf(new_status_file, "Package: %s\n", package_name);
                                        fprintf(new_status_file, "Status: %s\n", status_from_hashtable);

                                        while (1) {
                                                char *field_name;
                                                char *field_value;
                                                field_start += read_package_field(&control_buffer[field_start], &field_name, &field_value);
                                                if (field_name == NULL) {
                                                        break;
                                                }
                                                if ((strcmp(field_name, "Priority") == 0)
                                                 || (strcmp(field_name, "Section") == 0)
                                                ) {
                                                        fprintf(new_status_file, "%s: %s\n", field_name, field_value);
                                                }
                                        }
                                        write_flag = TRUE;
                                        fputs("\n", new_status_file);
                                }
                                else if (strcmp("config-files", name_hashtable[state_status]) == 0) {
                                        /* only change the status line */
                                        while (1) {
                                                char *field_name;
                                                char *field_value;
                                                field_start += read_package_field(&control_buffer[field_start], &field_name, &field_value);
                                                if (field_name == NULL) {
                                                        break;
                                                }
                                                /* Setup start point for next field */
                                                if (strcmp(field_name, "Status") == 0) {
                                                        fprintf(new_status_file, "Status: %s\n", status_from_hashtable);
                                                } else {
                                                        fprintf(new_status_file, "%s: %s\n", field_name, field_value);
                                                }
                                        }
                                        write_flag = TRUE;
                                        fputs("\n", new_status_file);
                                }
                        }
                }
                /* If the package from the status file wasn't handle above, do it now*/
                if (!write_flag) {
                        fprintf(new_status_file, "%s\n\n", control_buffer);
                }

                free(status_from_file);
                free(package_name);
                free(control_buffer);
        }

        /* Write any new packages */
        for (i = 0; deb_file[i] != NULL; i++) {
                status_num = search_status_hashtable(name_hashtable[package_hashtable[deb_file[i]->package]->name]);
                if (strcmp("reinstreq", name_hashtable[get_status(status_num, 2)]) == 0) {
                        write_buffer_no_status(new_status_file, deb_file[i]->control_file);
                        set_status(status_num, "ok", 2);
                        fprintf(new_status_file, "Status: %s\n\n", name_hashtable[status_hashtable[status_num]->status]);
                }
        }
        fclose(old_status_file);
        fclose(new_status_file);

        /* Create a separate backfile to dpkg */
        if (rename("/var/lib/dpkg/status", "/var/lib/dpkg/status.udeb.bak") == -1) {
                if (errno != ENOENT)
                        bb_simple_error_msg_and_die("can't create backup status file");
                /* Its ok if renaming the status file fails because status
                 * file doesn't exist, maybe we are starting from scratch */
                bb_simple_error_msg("no status file found, creating new one");
        }

        xrename("/var/lib/dpkg/status.udeb", "/var/lib/dpkg/status");
}

/* This function returns TRUE if the given package can satisfy a
 * dependency of type depend_type.
 *
 * A pre-depends is satisfied only if a package is already installed,
 * which a regular depends can be satisfied by a package which we want
 * to install.
 */
static int package_satisfies_dependency(int package, int depend_type)
{
        int status_num = search_status_hashtable(name_hashtable[package_hashtable[package]->name]);

        /* status could be unknown if package is a pure virtual
         * provides which cannot satisfy any dependency by itself.
         */
        if (status_hashtable[status_num] == NULL)
                return 0;

        switch (depend_type) {
        case EDGE_PRE_DEPENDS: return get_status(status_num, 3) == search_name_hashtable("installed");
        case EDGE_DEPENDS:     return get_status(status_num, 1) == search_name_hashtable("install");
        }
        return 0;
}

static int check_deps(deb_file_t **deb_file, int deb_start /*, int dep_max_count - ?? */)
{
        int *conflicts = NULL;
        int conflicts_num = 0;
        int i = deb_start;
        int j;

        /* Check for conflicts
         * TODO: TEST if conflicts with other packages to be installed
         *
         * Add install packages and the packages they provide
         * to the list of files to check conflicts for
         */

        /* Create array of package numbers to check against
         * installed package for conflicts*/
        while (deb_file[i] != NULL) {
                const unsigned package_num = deb_file[i]->package;
                conflicts = xrealloc_vector(conflicts, 2, conflicts_num);
                conflicts[conflicts_num] = package_num;
                conflicts_num++;

                /* add provides to conflicts list */
                for (j = 0; j < package_hashtable[package_num]->num_of_edges; j++) {
                        if (package_hashtable[package_num]->edge[j]->type == EDGE_PROVIDES) {
                                const int conflicts_package_num = search_package_hashtable(
                                        package_hashtable[package_num]->edge[j]->name,
                                        package_hashtable[package_num]->edge[j]->version,
                                        package_hashtable[package_num]->edge[j]->operator);
                                if (package_hashtable[conflicts_package_num] == NULL) {
                                        /* create a new package */
                                        common_node_t *new_node = xzalloc(sizeof(common_node_t));
                                        new_node->name = package_hashtable[package_num]->edge[j]->name;
                                        new_node->version = package_hashtable[package_num]->edge[j]->version;
                                        package_hashtable[conflicts_package_num] = new_node;
                                }
                                conflicts = xrealloc_vector(conflicts, 2, conflicts_num);
                                conflicts[conflicts_num] = conflicts_package_num;
                                conflicts_num++;
                        }
                }
                i++;
        }

        /* Check conflicts */
        i = 0;
        while (deb_file[i] != NULL) {
                const common_node_t *package_node = package_hashtable[deb_file[i]->package];
                int status_num = 0;
                status_num = search_status_hashtable(name_hashtable[package_node->name]);

                if (get_status(status_num, 3) == search_name_hashtable("installed")) {
                        i++;
                        continue;
                }

                for (j = 0; j < package_node->num_of_edges; j++) {
                        const edge_t *package_edge = package_node->edge[j];

                        if (package_edge->type == EDGE_CONFLICTS) {
                                const unsigned package_num =
                                        search_package_hashtable(package_edge->name,
                                                                package_edge->version,
                                                                package_edge->operator);
                                int result = 0;
                                if (package_hashtable[package_num] != NULL) {
                                        status_num = search_status_hashtable(name_hashtable[package_hashtable[package_num]->name]);

                                        if (get_status(status_num, 1) == search_name_hashtable("install")) {
                                                result = test_version(package_hashtable[deb_file[i]->package]->version,
                                                        package_edge->version, package_edge->operator);
                                        }
                                }

                                if (result) {
                                        bb_error_msg_and_die("package %s conflicts with %s",
                                                name_hashtable[package_node->name],
                                                name_hashtable[package_edge->name]);
                                }
                        }
                }
                i++;
        }


        /* Check dependentcies */
        for (i = 0; i < PACKAGE_HASH_PRIME; i++) {
                int status_num = 0;
                int number_of_alternatives = 0;
                const edge_t * root_of_alternatives = NULL;
                const common_node_t *package_node = package_hashtable[i];

                /* If the package node does not exist then this
                 * package is a virtual one. In which case there are
                 * no dependencies to check.
                 */
                if (package_node == NULL) continue;

                status_num = search_status_hashtable(name_hashtable[package_node->name]);

                /* If there is no status then this package is a
                 * virtual one provided by something else. In which
                 * case there are no dependencies to check.
                 */
                if (status_hashtable[status_num] == NULL) continue;

                /* If we don't want this package installed then we may
                 * as well ignore it's dependencies.
                 */
                if (get_status(status_num, 1) != search_name_hashtable("install")) {
                        continue;
                }

                /* This code is tested only for EDGE_DEPENDS, since I
                 * have no suitable pre-depends available. There is no
                 * reason that it shouldn't work though :-)
                 */
                for (j = 0; j < package_node->num_of_edges; j++) {
                        const edge_t *package_edge = package_node->edge[j];
                        unsigned package_num;

                        if (package_edge->type == EDGE_OR_PRE_DEPENDS
                         || package_edge->type == EDGE_OR_DEPENDS
                        ) {
                                /* start an EDGE_OR_ list */
                                number_of_alternatives = package_edge->version;
                                root_of_alternatives = package_edge;
                                continue;
                        }
                        if (number_of_alternatives == 0) {  /* not in the middle of an EDGE_OR_ list */
                                number_of_alternatives = 1;
                                root_of_alternatives = NULL;
                        }

                        package_num = search_package_hashtable(package_edge->name, package_edge->version, package_edge->operator);

                        if (package_edge->type == EDGE_PRE_DEPENDS
                         || package_edge->type == EDGE_DEPENDS
                        ) {
                                int result=1;
                                status_num = 0;

                                /* If we are inside an alternative then check
                                 * this edge is the right type.
                                 *
                                 * EDGE_DEPENDS == OR_DEPENDS -1
                                 * EDGE_PRE_DEPENDS == OR_PRE_DEPENDS -1
                                 */
                                if (root_of_alternatives && package_edge->type != root_of_alternatives->type - 1)
                                        bb_error_msg_and_die("fatal error, package dependencies corrupt: %d != %d - 1",
                                                        package_edge->type, root_of_alternatives->type);

                                if (package_hashtable[package_num] != NULL)
                                        result = !package_satisfies_dependency(package_num, package_edge->type);

                                if (result) { /* check for other package which provide what we are looking for */
                                        int provider = -1;

                                        while ((provider = search_for_provides(package_edge->name, provider)) > -1) {
                                                if (package_hashtable[provider] == NULL) {
                                                        puts("Have a provider but no package information for it");
                                                        continue;
                                                }
                                                result = !package_satisfies_dependency(provider, package_edge->type);

                                                if (result == 0)
                                                        break;
                                        }
                                }

                                /* It must be already installed, or to be installed */
                                number_of_alternatives--;
                                if (result && number_of_alternatives == 0) {
                                        if (root_of_alternatives)
                                                bb_error_msg_and_die(
                                                        "package %s %sdepends on %s, which %s",
                                                        name_hashtable[package_node->name],
                                                        package_edge->type == EDGE_PRE_DEPENDS ? "pre-" : "",
                                                        name_hashtable[root_of_alternatives->name],
                                                        "cannot be satisfied");
                                        bb_error_msg_and_die(
                                                "package %s %sdepends on %s, which %s",
                                                name_hashtable[package_node->name],
                                                package_edge->type == EDGE_PRE_DEPENDS ? "pre-" : "",
                                                name_hashtable[package_edge->name],
                                                describe_status(status_num));
                                }
                                if (result == 0 && number_of_alternatives) {
                                        /* we've found a package which
                                         * satisfies the dependency,
                                         * so skip over the rest of
                                         * the alternatives.
                                         */
                                        j += number_of_alternatives;
                                        number_of_alternatives = 0;
                                }
                        }
                }
        }
        free(conflicts);
        return TRUE;
}

static char **create_list(const char *filename)
{
        FILE *list_stream;
        char **file_list;
        char *line;
        int count;

        /* don't use [xw]fopen here, handle error ourself */
        list_stream = fopen_for_read(filename);
        if (list_stream == NULL) {
                return NULL;
        }

        file_list = NULL;
        count = 0;
        while ((line = xmalloc_fgetline(list_stream)) != NULL) {
                file_list = xrealloc_vector(file_list, 2, count);
                file_list[count++] = line;
                /*file_list[count] = NULL; - xrealloc_vector did it */
        }
        fclose(list_stream);

        return file_list;
}

/** This tests if the filename is an "important" directory, which might be symlinked.
 *  Debians dpkg test if directories are used by other packages, this
 *  implementation doesn't and would remove for ex. an lib -> usr/lib symlink.
 */
static int is_builtin_exclude(const char *name)
{
        if (*name++ != '/')
                return 0;
        if (index_in_strings(".\0" "etc\0" "opt\0" "srv\0" "var\0" "var/lib\0",
                        name) >= 0)
                return 1;
        if (is_prefixed_with(name, "usr/")) {
                name += sizeof("usr/") - 1;
                if (is_prefixed_with(name, "local/"))
                        name += sizeof("local/") - 1;
        }

        return index_in_strings("bin\0" "lib\0" "lib32\0" "lib64\0" "sbin\0",
                        name) >= 0;
}

/* maybe i should try and hook this into remove_file.c somehow */
static int remove_file_array(char **remove_names, char **exclude_names)
{
        struct stat path_stat;
        int remove_flag = 1; /* not removed anything yet */
        int i, j;

        if (remove_names == NULL) {
                return 0;
        }
        for (i = 0; remove_names[i] != NULL; i++) {
                if (is_builtin_exclude(remove_names[i]))
                        continue;
                if (exclude_names != NULL) {
                        for (j = 0; exclude_names[j] != NULL; j++) {
                                if (strcmp(remove_names[i], exclude_names[j]) == 0) {
                                        goto skip;
                                }
                        }
                }
                /* TODO: why we are checking lstat? we can just try rm/rmdir */
                if (lstat(remove_names[i], &path_stat) < 0) {
                        continue;
                }
                if (S_ISDIR(path_stat.st_mode)) {
                        remove_flag &= rmdir(remove_names[i]); /* 0 if no error */
                } else {
                        remove_flag &= unlink(remove_names[i]); /* 0 if no error */
                }
 skip:
                continue;
        }
        return (remove_flag == 0);
}

static void run_package_script_or_die(const char *package_name, const char *script_type)
{
        char *script_path;
        int result;

        script_path = xasprintf("/var/lib/dpkg/info/%s.%s", package_name, script_type);

        /* If the file doesn't exist it isn't fatal */
        result = access(script_path, F_OK) ? EXIT_SUCCESS : system(script_path);
        free(script_path);
        if (result)
                bb_error_msg_and_die("%s failed, exit code %d", script_type, result);
}

/*
The policy manual defines what scripts get called when and with
what arguments. I realize that busybox does not support all of
these scenarios, but it does support some of them; it does not,
however, run them with any parameters in run_package_script_or_die().
Here are the scripts:

preinst install
preinst install <old_version>
preinst upgrade <old_version>
preinst abort_upgrade <new_version>
postinst configure <most_recent_version>
postinst abort-upgade <new_version>
postinst abort-remove
postinst abort-remove in-favour <package> <version>
postinst abort-deconfigure in-favor <failed_install_package> removing <conflicting_package> <version>
prerm remove
prerm upgrade <new_version>
prerm failed-upgrade <old_version>
prerm remove in-favor <package> <new_version>
prerm deconfigure in-favour <package> <version> removing <package> <version>
postrm remove
postrm purge
postrm upgrade <new_version>
postrm failed-upgrade <old_version>
postrm abort-install
postrm abort-install <old_version>
postrm abort-upgrade <old_version>
postrm disappear <overwriter> <version>
*/
static const char *const all_control_files[] ALIGN_PTR = {
        "preinst", "postinst", "prerm", "postrm",
        "list", "md5sums", "shlibs", "conffiles",
        "config", "templates"
};

static char **all_control_list(const char *package_name)
{
        unsigned i = 0;
        char **remove_files;

        /* Create a list of all /var/lib/dpkg/info/<package> files */
        remove_files = xzalloc(sizeof(all_control_files) + sizeof(char*));
        while (i < ARRAY_SIZE(all_control_files)) {
                remove_files[i] = xasprintf("/var/lib/dpkg/info/%s.%s",
                                package_name, all_control_files[i]);
                i++;
        }

        return remove_files;
}

static void free_array(char **array)
{
        if (array) {
                unsigned i = 0;
                while (array[i]) {
                        free(array[i]);
                        i++;
                }
                free(array);
        }
}

/* This function lists information on the installed packages. It loops through
 * the status_hashtable to retrieve the info. This results in smaller code than
 * scanning the status file. The resulting list, however, is unsorted.
 */
static void list_packages(const char *pattern)
{
        int i;

        puts("    Name           Version");
        puts("+++-==============-==============");

        /* go through status hash, dereference package hash and finally strings */
        for (i = 0; i < STATUS_HASH_PRIME+1; i++) {
                if (status_hashtable[i]) {
                        const char *stat_str;  /* status string */
                        const char *name_str;  /* package name */
                        const char *vers_str;  /* version */
                        char  s1, s2;          /* status abbreviations */
                        int   spccnt;          /* space count */
                        int   j;

                        stat_str = name_hashtable[status_hashtable[i]->status];
                        name_str = name_hashtable[package_hashtable[status_hashtable[i]->package]->name];
                        vers_str = name_hashtable[package_hashtable[status_hashtable[i]->package]->version];

                        if (pattern && fnmatch(pattern, name_str, 0) != 0)
                                continue;

                        /* get abbreviation for status field 1 */
                        s1 = stat_str[0] == 'i' ? 'i' : 'r';

                        /* get abbreviation for status field 2 */
                        for (j = 0, spccnt = 0; stat_str[j] && spccnt < 2; j++) {
                                if (stat_str[j] == ' ') spccnt++;
                        }
                        s2 = stat_str[j];

                        /* print out the line formatted like Debian dpkg */
                        printf("%c%c  %-14s %s\n", s1, s2, name_str, vers_str);
                }
        }
}

static void remove_package(const unsigned package_num, int noisy)
{
        const char *package_name = name_hashtable[package_hashtable[package_num]->name];
        const char *package_version = name_hashtable[package_hashtable[package_num]->version];
        const unsigned status_num = search_status_hashtable(package_name);
        const int package_name_length = strlen(package_name);
        char **remove_files;
        char **exclude_files;
        char list_name[package_name_length + 25];
        char conffile_name[package_name_length + 30];

        if (noisy)
                printf("Removing %s (%s)...\n", package_name, package_version);

        /* Run prerm script */
        run_package_script_or_die(package_name, "prerm");

        /* Create a list of files to remove, and a separate list of those to keep */
        sprintf(list_name, "/var/lib/dpkg/info/%s.%s", package_name, "list");
        remove_files = create_list(list_name);

        sprintf(conffile_name, "/var/lib/dpkg/info/%s.%s", package_name, "conffiles");
        exclude_files = create_list(conffile_name);

        /* Some directories can't be removed straight away, so do multiple passes */
        while (remove_file_array(remove_files, exclude_files))
                continue;
        free_array(exclude_files);
        free_array(remove_files);

        /* Create a list of files in /var/lib/dpkg/info/<package>.* to keep */
        exclude_files = xzalloc(sizeof(exclude_files[0]) * 3);
        exclude_files[0] = xstrdup(conffile_name);
        exclude_files[1] = xasprintf("/var/lib/dpkg/info/%s.%s", package_name, "postrm");

        /* Create a list of all /var/lib/dpkg/info/<package> files */
        remove_files = all_control_list(package_name);

        remove_file_array(remove_files, exclude_files);
        free_array(remove_files);
        free_array(exclude_files);

        /* rename <package>.conffiles to <package>.list
         * The conffiles control file isn't required in Debian packages, so don't
         * error out if it's missing.  */
        rename(conffile_name, list_name);

        /* Change package status */
        set_status(status_num, "config-files", 3);
}

static void purge_package(const unsigned package_num)
{
        const char *package_name = name_hashtable[package_hashtable[package_num]->name];
        const char *package_version = name_hashtable[package_hashtable[package_num]->version];
        const unsigned status_num = search_status_hashtable(package_name);
        char **remove_files;
        char **exclude_files;
        char list_name[strlen(package_name) + 25];

        printf("Purging %s (%s)...\n", package_name, package_version);

        /* Run prerm script */
        run_package_script_or_die(package_name, "prerm");

        /* Create a list of files to remove */
        sprintf(list_name, "/var/lib/dpkg/info/%s.%s", package_name, "list");
        remove_files = create_list(list_name);

        /* Some directories cant be removed straight away, so do multiple passes */
        while (remove_file_array(remove_files, NULL))
                continue;
        free_array(remove_files);

        /* Create a list of all /var/lib/dpkg/info/<package> files */
        remove_files = all_control_list(package_name);

        /* Delete all of them except the postrm script */
        exclude_files = xzalloc(sizeof(exclude_files[0]) * 2);
        exclude_files[0] = xasprintf("/var/lib/dpkg/info/%s.%s", package_name, "postrm");
        remove_file_array(remove_files, exclude_files);
        free_array(exclude_files);

        /* Run and remove postrm script */
        run_package_script_or_die(package_name, "postrm");
        remove_file_array(remove_files, NULL);

        free_array(remove_files);

        /* Change package status */
        set_status(status_num, "not-installed", 3);
}

static archive_handle_t *init_archive_deb_ar(const char *filename)
{
        archive_handle_t *ar_handle;

        /* Setup an ar archive handle that refers to the gzip sub archive */
        ar_handle = init_handle();
        ar_handle->filter = filter_accept_list_reassign;
        ar_handle->src_fd = xopen(filename, O_RDONLY);

        return ar_handle;
}

static void init_archive_deb_control(archive_handle_t *ar_handle)
{
        archive_handle_t *tar_handle;

        /* Setup the tar archive handle */
        tar_handle = init_handle();
        tar_handle->src_fd = ar_handle->src_fd;

        /* We don't care about data.tar.* or debian-binary, just control.tar.* */
        llist_add_to(&(ar_handle->accept), (char*)"control.tar");
#if ENABLE_FEATURE_SEAMLESS_GZ
        llist_add_to(&(ar_handle->accept), (char*)"control.tar.gz");
#endif
#if ENABLE_FEATURE_SEAMLESS_BZ2
        llist_add_to(&(ar_handle->accept), (char*)"control.tar.bz2");
#endif
#if ENABLE_FEATURE_SEAMLESS_XZ
        llist_add_to(&(ar_handle->accept), (char*)"control.tar.xz");
#endif

        /* Assign the tar handle as a subarchive of the ar handle */
        ar_handle->dpkg__sub_archive = tar_handle;
}

static void init_archive_deb_data(archive_handle_t *ar_handle)
{
        archive_handle_t *tar_handle;

        /* Setup the tar archive handle */
        tar_handle = init_handle();
        tar_handle->src_fd = ar_handle->src_fd;

        /* We don't care about control.tar.* or debian-binary, just data.tar.* */
        llist_add_to(&(ar_handle->accept), (char*)"data.tar");
#if ENABLE_FEATURE_SEAMLESS_GZ
        llist_add_to(&(ar_handle->accept), (char*)"data.tar.gz");
#endif
#if ENABLE_FEATURE_SEAMLESS_BZ2
        llist_add_to(&(ar_handle->accept), (char*)"data.tar.bz2");
#endif
#if ENABLE_FEATURE_SEAMLESS_LZMA
        llist_add_to(&(ar_handle->accept), (char*)"data.tar.lzma");
#endif
#if ENABLE_FEATURE_SEAMLESS_XZ
        llist_add_to(&(ar_handle->accept), (char*)"data.tar.xz");
#endif

        /* Assign the tar handle as a subarchive of the ar handle */
        ar_handle->dpkg__sub_archive = tar_handle;
}

static void FAST_FUNC data_extract_to_buffer(archive_handle_t *archive_handle)
{
        unsigned size = archive_handle->file_header->size;

        archive_handle->dpkg__buffer = xzalloc(size + 1);
        xread(archive_handle->src_fd, archive_handle->dpkg__buffer, size);
}

static char *deb_extract_control_file_to_buffer(archive_handle_t *ar_handle, llist_t *myaccept)
{
        ar_handle->dpkg__sub_archive->action_data = data_extract_to_buffer;
        ar_handle->dpkg__sub_archive->accept = myaccept;
        ar_handle->dpkg__sub_archive->filter = filter_accept_list;

        unpack_ar_archive(ar_handle);
        close(ar_handle->src_fd);

        return ar_handle->dpkg__sub_archive->dpkg__buffer;
}

static void append_control_file_to_llist(const char *package_name, const char *control_name, llist_t **ll)
{
        FILE *fp;
        char *filename, *line;

        filename = xasprintf("/var/lib/dpkg/info/%s.%s", package_name, control_name);
        fp = fopen_for_read(filename);
        free(filename);
        if (fp != NULL) {
                while ((line = xmalloc_fgetline(fp)) != NULL)
                        llist_add_to(ll, line);
                fclose(fp);
        }
}

static char FAST_FUNC filter_rename_config(archive_handle_t *archive_handle)
{
        int fd;
        char *name_ptr = archive_handle->file_header->name + 1;

        /* Is this file marked as config file? */
        if (!find_list_entry(archive_handle->accept, name_ptr))
                return EXIT_SUCCESS; /* no */

        fd = open(name_ptr, O_RDONLY);
        if (fd >= 0) {
                md5_ctx_t md5;
                char *md5line, *buf;
                int count;

                /* Calculate MD5 of existing file */
                buf = xmalloc(4096);
                md5_begin(&md5);
                while ((count = safe_read(fd, buf, 4096)) > 0)
                        md5_hash(&md5, buf, count);
                md5_end(&md5, buf); /* using buf as result storage */
                close(fd);

                md5line = xmalloc(16 * 2 + 2 + strlen(name_ptr) + 1);
                sprintf(bin2hex(md5line, buf, 16), "  %s", name_ptr);
                free(buf);

                /* Is it changed after install? */
                if (find_list_entry(archive_handle->accept, md5line) == NULL) {
                        printf("Warning: Creating %s as %s.dpkg-new\n", name_ptr, name_ptr);
                        archive_handle->file_header->name = xasprintf("%s.dpkg-new", archive_handle->file_header->name);
                }
                free(md5line);
        }
        return EXIT_SUCCESS;
}

static void FAST_FUNC data_extract_all_prefix(archive_handle_t *archive_handle)
{
        char *name_ptr = archive_handle->file_header->name;

        /* Skip all leading "/" */
        while (*name_ptr == '/')
                name_ptr++;
        /* Skip all leading "./" and "../" */
        while (name_ptr[0] == '.') {
                if (name_ptr[1] == '.')
                        name_ptr++;
                if (name_ptr[1] != '/')
                        break;
                name_ptr += 2;
        }

        if (name_ptr[0] != '\0') {
                archive_handle->file_header->name = xasprintf("%s%s", archive_handle->dpkg__buffer, name_ptr);
                data_extract_all(archive_handle);
                if (fnmatch("*.dpkg-new", archive_handle->file_header->name, 0) == 0) {
                        /* remove .dpkg-new suffix */
                        archive_handle->file_header->name[strlen(archive_handle->file_header->name) - 9] = '\0';
                }
        }
}

enum {
        /* Commands */
        OPT_configure            = (1 << 0),
        OPT_install              = (1 << 1),
        OPT_list_installed       = (1 << 2),
        OPT_purge                = (1 << 3),
        OPT_remove               = (1 << 4),
        OPT_unpack               = (1 << 5),
        OPTMASK_cmd              = (1 << 6) - 1,
        /* Options */
        OPT_force                = (1 << 6),
        OPT_force_ignore_depends = (1 << 7),
        OPT_force_confnew        = (1 << 8),
        OPT_force_confold        = (1 << 9),
};

static void unpack_package(deb_file_t *deb_file)
{
        const char *package_name = name_hashtable[package_hashtable[deb_file->package]->name];
        const unsigned status_num = search_status_hashtable(package_name);
        const unsigned status_package_num = status_hashtable[status_num]->package;
        char *info_prefix;
        char *list_filename;
        archive_handle_t *archive_handle;
        FILE *out_stream;
        llist_t *accept_list;
        llist_t *conffile_list;
        int i;

        /* If existing version, remove it first */
        conffile_list = NULL;
        if (strcmp(name_hashtable[get_status(status_num, 3)], "installed") == 0) {
                /* Package is already installed, remove old version first */
                printf("Preparing to replace %s %s (using %s)...\n", package_name,
                        name_hashtable[package_hashtable[status_package_num]->version],
                        deb_file->filename);

                /* Read md5sums from old package */
                if (!(option_mask32 & OPT_force_confold))
                        append_control_file_to_llist(package_name, "md5sums", &conffile_list);

                remove_package(status_package_num, 0);
        } else {
                printf("Unpacking %s (from %s)...\n", package_name, deb_file->filename);
        }

        /* Extract control.tar.gz to /var/lib/dpkg/info/<package>.filename */
        info_prefix = xasprintf("/var/lib/dpkg/info/%s.%s", package_name, "");
        archive_handle = init_archive_deb_ar(deb_file->filename);
        init_archive_deb_control(archive_handle);

        accept_list = NULL;
        i = 0;
        while (i < ARRAY_SIZE(all_control_files)) {
                char *c = xasprintf("./%s", all_control_files[i]);
                llist_add_to(&accept_list, c);
                i++;
        }
        archive_handle->dpkg__sub_archive->accept = accept_list;
        archive_handle->dpkg__sub_archive->filter = filter_accept_list;
        archive_handle->dpkg__sub_archive->action_data = data_extract_all_prefix;
        archive_handle->dpkg__sub_archive->dpkg__buffer = info_prefix;
        archive_handle->dpkg__sub_archive->ah_flags |= ARCHIVE_UNLINK_OLD;
        unpack_ar_archive(archive_handle);

        /* Run the preinst prior to extracting */
        run_package_script_or_die(package_name, "preinst");

        /* Don't overwrite existing config files */
        if (!(option_mask32 & OPT_force_confnew))
                append_control_file_to_llist(package_name, "conffiles", &conffile_list);

        /* Extract data.tar.gz to the root directory */
        archive_handle = init_archive_deb_ar(deb_file->filename);
        init_archive_deb_data(archive_handle);
        archive_handle->dpkg__sub_archive->accept = conffile_list;
        /* Why ARCHIVE_REMEMBER_NAMES?
         * We want names collected in ->passed list even if conffile_list
         * is NULL (otherwise get_header_tar may optimize name saving out):
         */
        archive_handle->dpkg__sub_archive->ah_flags |= ARCHIVE_REMEMBER_NAMES | ARCHIVE_UNLINK_OLD;
        archive_handle->dpkg__sub_archive->filter = filter_rename_config;
        archive_handle->dpkg__sub_archive->action_data = data_extract_all_prefix;
        archive_handle->dpkg__sub_archive->dpkg__buffer = (char*)"/"; /* huh? */
        unpack_ar_archive(archive_handle);

        /* Create the list file */
        list_filename = xasprintf("/var/lib/dpkg/info/%s.%s", package_name, "list");
        out_stream = xfopen_for_write(list_filename);
        archive_handle->dpkg__sub_archive->passed = llist_rev(archive_handle->dpkg__sub_archive->passed);
        while (archive_handle->dpkg__sub_archive->passed) {
                char *filename = llist_pop(&archive_handle->dpkg__sub_archive->passed);
                /* the leading . has been stripped by data_extract_all_prefix already */
                fprintf(out_stream, "%s\n", filename);
                free(filename);
        }
        fclose(out_stream);

        /* change status */
        set_status(status_num, "install", 1);
        set_status(status_num, "unpacked", 3);

        free(info_prefix);
        free(list_filename);
}

static void configure_package(deb_file_t *deb_file)
{
        const char *package_name = name_hashtable[package_hashtable[deb_file->package]->name];
        const char *package_version = name_hashtable[package_hashtable[deb_file->package]->version];
        const int status_num = search_status_hashtable(package_name);

        printf("Setting up %s (%s)...\n", package_name, package_version);

        /* Run the postinst script */
        /* TODO: handle failure gracefully */
        run_package_script_or_die(package_name, "postinst");

        /* Change status to reflect success */
        set_status(status_num, "install", 1);
        set_status(status_num, "installed", 3);
}

int dpkg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dpkg_main(int argc UNUSED_PARAM, char **argv)
{
        deb_file_t **deb_file = NULL;
        status_node_t *status_node;
        char *str_f;
        int opt;
        int package_num;
        int deb_count = 0;
        int state_status;
        int status_num;
        int i;
#if ENABLE_LONG_OPTS
        static const char dpkg_longopts[] ALIGN1 =
// FIXME: we use -C non-compatibly, should be:
// "-C|--audit Check for broken package(s)"
                "configure\0"      No_argument        "C"
                "force\0"          Required_argument  "F"
                "install\0"        No_argument        "i"
                "list\0"           No_argument        "l"
                "purge\0"          No_argument        "P"
                "remove\0"         No_argument        "r"
                "unpack\0"         No_argument        "u"
                "force-depends\0"  No_argument        "\xff"
                "force-confnew\0"  No_argument        "\xfe"
                "force-confold\0"  No_argument        "\xfd"
                ;
#endif

        INIT_G();

        opt = getopt32long(argv, "CilPruF:", dpkg_longopts, &str_f);
        argv += optind;
        //if (opt & OPT_configure) ... // -C
        if (opt & OPT_force) { // -F (--force in official dpkg)
                if (strcmp(str_f, "depends") == 0)
                        opt |= OPT_force_ignore_depends;
                else if (strcmp(str_f, "confnew") == 0)
                        opt |= OPT_force_confnew;
                else if (strcmp(str_f, "confold") == 0)
                        opt |= OPT_force_confold;
                else
                        bb_show_usage();
                option_mask32 = opt;
        }
        //if (opt & OPT_install) ... // -i
        //if (opt & OPT_list_installed) ... // -l
        //if (opt & OPT_purge) ... // -P
        //if (opt & OPT_remove) ... // -r
        //if (opt & OPT_unpack) ... // -u (--unpack in official dpkg)
        if (!(opt & OPTMASK_cmd) /* no cmd */
         || ((opt & OPTMASK_cmd) & ((opt & OPTMASK_cmd)-1)) /* more than one cmd */
        ) {
                bb_show_usage();
        }

/*      puts("(Reading database ... xxxxx files and directories installed.)"); */
        index_status_file("/var/lib/dpkg/status");

        /* if the list action was given print the installed packages and exit */
        if (opt & OPT_list_installed) {
                list_packages(argv[0]); /* param can be NULL */
                return EXIT_SUCCESS;
        }

        /* Read arguments and store relevant info in structs */
        while (*argv) {
                /* deb_count = nb_elem - 1 and we need nb_elem + 1 to allocate terminal node [NULL pointer] */
                deb_file = xrealloc_vector(deb_file, 2, deb_count);
                deb_file[deb_count] = xzalloc(sizeof(deb_file[0][0]));
                if (opt & (OPT_install | OPT_unpack)) {
                        /* -i/-u: require filename */
                        archive_handle_t *archive_handle;
                        llist_t *control_list = NULL;

                        /* Extract the control file */
                        llist_add_to(&control_list, (char*)"./control");
                        archive_handle = init_archive_deb_ar(argv[0]);
                        init_archive_deb_control(archive_handle);
                        deb_file[deb_count]->control_file = deb_extract_control_file_to_buffer(archive_handle, control_list);
                        if (deb_file[deb_count]->control_file == NULL) {
                                bb_simple_error_msg_and_die("can't extract control file");
                        }
                        deb_file[deb_count]->filename = xstrdup(argv[0]);
                        package_num = fill_package_struct(deb_file[deb_count]->control_file);

                        if (package_num == -1) {
                                bb_error_msg("invalid control file in %s", argv[0]);
                                argv++;
                                continue;
                        }
                        deb_file[deb_count]->package = (unsigned) package_num;

                        /* Add the package to the status hashtable */
                        if (opt & (OPT_unpack | OPT_install)) {
                                /* Try and find a currently installed version of this package */
                                status_num = search_status_hashtable(name_hashtable[package_hashtable[deb_file[deb_count]->package]->name]);
                                /* If no previous entry was found initialise a new entry */
                                if (status_hashtable[status_num] == NULL
                                 || status_hashtable[status_num]->status == 0
                                ) {
                                        status_node = xmalloc(sizeof(status_node_t));
                                        status_node->package = deb_file[deb_count]->package;
                                        /* reinstreq isn't changed to "ok" until the package control info
                                         * is written to the status file*/
                                        status_node->status = search_name_hashtable("install reinstreq not-installed");
                                        status_hashtable[status_num] = status_node;
                                } else {
                                        set_status(status_num, "install", 1);
                                        set_status(status_num, "reinstreq", 2);
                                }
                        }
                } else if (opt & (OPT_configure | OPT_purge | OPT_remove)) {
                        /* -C/-p/-r: require package name */
                        deb_file[deb_count]->package = search_package_hashtable(
                                        search_name_hashtable(argv[0]),
                                        search_name_hashtable("ANY"), VER_ANY);
                        if (package_hashtable[deb_file[deb_count]->package] == NULL) {
                                bb_error_msg_and_die("package %s is uninstalled or unknown", argv[0]);
                        }
                        package_num = deb_file[deb_count]->package;
                        status_num = search_status_hashtable(name_hashtable[package_hashtable[package_num]->name]);
                        state_status = get_status(status_num, 3);

                        /* check package status is "installed" */
                        if (opt & OPT_remove) {
                                if (strcmp(name_hashtable[state_status], "not-installed") == 0
                                 || strcmp(name_hashtable[state_status], "config-files") == 0
                                ) {
                                        bb_error_msg_and_die("%s is already removed", name_hashtable[package_hashtable[package_num]->name]);
                                }
                                set_status(status_num, "deinstall", 1);
                        } else if (opt & OPT_purge) {
                                /* if package status is "conf-files" then its ok */
                                if (strcmp(name_hashtable[state_status], "not-installed") == 0) {
                                        bb_error_msg_and_die("%s is already purged", name_hashtable[package_hashtable[package_num]->name]);
                                }
                                set_status(status_num, "purge", 1);
                        }
                }
                deb_count++;
                argv++;
        }
        if (!deb_count)
                bb_simple_error_msg_and_die("no package files specified");
        deb_file[deb_count] = NULL;

        /* Check that the deb file arguments are installable */
        if (!(opt & OPT_force_ignore_depends)) {
                if (!check_deps(deb_file, 0 /*, deb_count*/)) {
                        bb_simple_error_msg_and_die("dependency check failed");
                }
        }

        /* TODO: install or remove packages in the correct dependency order */
        for (i = 0; i < deb_count; i++) {
                /* Remove or purge packages */
                if (opt & OPT_remove) {
                        remove_package(deb_file[i]->package, 1);
                }
                else if (opt & OPT_purge) {
                        purge_package(deb_file[i]->package);
                }
                else if (opt & OPT_unpack) {
                        unpack_package(deb_file[i]);
                }
                else if (opt & OPT_install) {
                        unpack_package(deb_file[i]);
                        /* package is configured in second pass below */
                }
                else if (opt & OPT_configure) {
                        configure_package(deb_file[i]);
                }
        }
        /* configure installed packages */
        if (opt & OPT_install) {
                for (i = 0; i < deb_count; i++)
                        configure_package(deb_file[i]);
        }

        write_status_file(deb_file);

        if (ENABLE_FEATURE_CLEAN_UP) {
                for (i = 0; i < deb_count; i++) {
                        free(deb_file[i]->control_file);
                        free(deb_file[i]->filename);
                        free(deb_file[i]);
                }

                free(deb_file);

                for (i = 0; i < NAME_HASH_PRIME; i++) {
                        free(name_hashtable[i]);
                }

                for (i = 0; i < PACKAGE_HASH_PRIME; i++) {
                        free_package(package_hashtable[i]);
                }

                for (i = 0; i < STATUS_HASH_PRIME; i++) {
                        free(status_hashtable[i]);
                }
        }

        return EXIT_SUCCESS;
}