/*
 * Copyright (C) 2018 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
 */

#include "smatch.h"
#include "smatch_extra.h"
#include "smatch_slist.h"

static int my_id;

struct db_info {
        int count;
        struct symbol *type;
        struct range_list *rl;
};

static int get_vals(void *_db_info, int argc, char **argv, char **azColName)
{
        struct db_info *db_info = _db_info;
        struct range_list *rl;

        str_to_rl(db_info->type, argv[0], &rl);
        db_info->rl = rl_union(db_info->rl, rl);

        return 0;
}

static int is_file_local(struct expression *array)
{
        struct symbol *sym = NULL;
        char *name;

        name = expr_to_str_sym(array, &sym);
        free_string(name);
        if (!sym)
                return 0;

        if ((sym->ctype.modifiers & MOD_TOPLEVEL) &&
            (sym->ctype.modifiers & MOD_STATIC))
                return 1;
        return 0;
}

static char *get_toplevel_name(struct expression *array)
{
        char *name;
        char buf[128];

        if (is_array(array))
                array = get_array_base(array);

        if (!array || array->type != EXPR_SYMBOL)
                return NULL;
        if (!is_file_local(array))
                return NULL;

        name = expr_to_str(array);
        snprintf(buf, sizeof(buf), "%s[]", name);
        free_string(name);

        return alloc_sname(buf);
}

static char *get_member_array(struct expression *array)
{
        char *name;
        char buf[128];

        name = get_member_name(array);
        if (!name)
                return NULL;
        snprintf(buf, sizeof(buf), "%s[]", name);
        free_string(name);
        return alloc_sname(buf);
}

static char *get_array_name(struct expression *array)
{
        struct symbol *type;
        char *name;

        type = get_type(array);
        if (!type || type->type != SYM_ARRAY)
                return NULL;

        name = get_toplevel_name(array);
        if (name)
                return name;
        name = get_member_array(array);
        if (name)
                return name;

        return NULL;
}

int get_array_rl(struct expression *expr, struct range_list **rl)
{
        struct expression *array;
        struct symbol *type;
        struct db_info db_info = {};
        char *name;

        type = get_type(expr);
        if (!type || type->type != SYM_BASETYPE)
                return 0;
        db_info.type = type;

        array = get_array_base(expr);
        name = get_array_name(array);
        if (!name)
                return 0;

        if (is_file_local(array)) {
                run_sql(&get_vals, &db_info,
                        "select value from sink_info where file = '%s' and static = 1 and sink_name = '%s' and type = %d;",
                        get_filename(), name, DATA_VALUE);
        } else {
                run_sql(&get_vals, &db_info,
                        "select value from sink_info where sink_name = '%s' and type = %d limit 10;",
                        name, DATA_VALUE);
        }
        if (!db_info.rl || db_info.count >= 10)
                return 0;

        *rl = db_info.rl;
        return 1;
}

static struct range_list *get_saved_rl(struct symbol *type, char *name)
{
        struct db_info db_info = {.type = type};

        cache_sql(&get_vals, &db_info, "select value from sink_info where sink_name = '%s' and type = %d;",
                  name, DATA_VALUE);
        return db_info.rl;
}

static void update_cache(char *name, int is_static, struct range_list *rl)
{
        cache_sql(NULL, NULL, "delete from sink_info where sink_name = '%s' and type = %d;",
                  name, DATA_VALUE);
        cache_sql(NULL, NULL, "insert into sink_info values ('%s', %d, '%s', %d, '', '%s');",
                  get_filename(), is_static, name, DATA_VALUE, show_rl(rl));
}

static void match_assign(struct expression *expr)
{
        struct expression *left, *array;
        struct range_list *orig_rl, *rl;
        struct symbol *type;
        char *name;

        type = get_type(expr->left);
        if (!type || type->type != SYM_BASETYPE)
                return;

        left = strip_expr(expr->left);
        if (!is_array(left))
                return;
        array = get_array_base(left);
        name = get_array_name(array);
        if (!name)
                return;

        if (expr->op != '=') {
                rl = alloc_whole_rl(get_type(expr->right));
                rl = cast_rl(type, rl);
        } else {
                get_absolute_rl(expr->right, &rl);
                rl = cast_rl(type, rl);
                orig_rl = get_saved_rl(type, name);
                rl = rl_union(orig_rl, rl);
        }

        update_cache(name, is_file_local(array), rl);
}

static void mark_strings_unknown(const char *fn, struct expression *expr, void *_arg)
{
        struct expression *dest;
        struct symbol *type;
        int arg = PTR_INT(_arg);
        char *name;

        dest = get_argument_from_call_expr(expr->args, arg);
        if (!dest)
                return;
        name = get_array_name(dest);
        if (!name)
                return;
        type = get_type(dest);
        if (type_is_ptr(type))
                type = get_real_base_type(type);
        update_cache(name, is_file_local(dest), alloc_whole_rl(type));
}

void register_array_values(int id)
{
        my_id = id;

        add_hook(&match_assign, ASSIGNMENT_HOOK);
        add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);

        add_function_hook("sprintf", &mark_strings_unknown, INT_PTR(0));
        add_function_hook("snprintf", &mark_strings_unknown, INT_PTR(0));

        add_function_hook("strcpy", &mark_strings_unknown, INT_PTR(0));
        add_function_hook("strncpy", &mark_strings_unknown, INT_PTR(0));
        add_function_hook("strlcpy", &mark_strings_unknown, INT_PTR(0));
        add_function_hook("strscpy", &mark_strings_unknown, INT_PTR(0));
}