check_allocation_funcs.c

/*
 * Copyright (C) 2009 Dan Carpenter.
 *
 * 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 <fcntl.h>
#include <unistd.h>
#include "parse.h"
#include "smatch.h"
#include "smatch_slist.h"

static int my_id;

/*
 * Print a list of functions that return newly allocated memory.
 */

static struct tracker_list *allocated;

static const char *allocation_funcs[] = {
	"kmalloc",
	"kmalloc_node",
	"kzalloc",
	"kzalloc_node",
	"vmalloc",
	"vzalloc",
	"__vmalloc",
	"kvmalloc",
	"kcalloc",
	"__alloc_skb",
	"kvcalloc",
	"kmalloc_array",
	"devm_kmalloc_array",
	"sock_kmalloc",
	"kmemdup",
	"memdup_user",
	"dma_alloc_attrs",
	"pci_alloc_consistent",
	"pci_alloc_coherent",
	"devm_kmalloc",
	"devm_kzalloc",
	"krealloc",
	"__alloc_bootmem",
	"alloc_bootmem",
	"get_zeroed_page",
	"alloc_page",
	"alloc_pages",
	"alloc_pages_current",
	"__get_free_pages",
	"dma_alloc_contiguous",
	"dma_alloc_coherent",
	NULL,
};

static void match_allocation(const char *fn, struct expression *expr,
			     void *info)
{
	char *left_name;
	struct symbol *left_sym;

	left_name = expr_to_var_sym(expr->left, &left_sym);
	if (!left_name || !left_sym)
		goto free;
	if (left_sym->ctype.modifiers & 
	    (MOD_NONLOCAL | MOD_STATIC | MOD_ADDRESSABLE))
		goto free;
	add_tracker(&allocated, my_id, left_name, left_sym);
free:
	free_string(left_name);
}

static int returns_new_stuff = 0;
static int returns_old_stuff = 0;
static void match_return(struct expression *ret_value)
{
	char *name;
	struct symbol *sym;
	sval_t tmp;

	if (__inline_fn)
		return;
	if (get_value(ret_value, &tmp) && tmp.value == 0)
		return;
	returns_new_stuff = 1;
	name = expr_to_var_sym(ret_value, &sym);
	if (!name || !sym) {
		returns_old_stuff = 1;
		goto free;
	}
	if (!in_tracker_list(allocated, my_id, name, sym))
		returns_old_stuff = 1;
free:
	free_string(name);
}

static void match_end_func(struct symbol *sym)
{
	if (__inline_fn)
		return;
	if (returns_new_stuff && !returns_old_stuff)
		sm_info("allocation func");
	free_trackers_and_list(&allocated);
	returns_new_stuff = 0;
	returns_old_stuff = 0;
}

void check_allocation_funcs(int id)
{
	int i;

	if (!option_info || option_project != PROJ_KERNEL)
		return;

	my_id = id;
	add_hook(&match_return, RETURN_HOOK);
	add_hook(&match_end_func, AFTER_FUNC_HOOK);
	for (i = 0; allocation_funcs[i]; i++) {
		add_function_assign_hook(allocation_funcs[i],
					 &match_allocation, NULL);
	}
}