linux-zen-desktop/scripts/coccinelle/misc/do_div.cocci

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// SPDX-License-Identifier: GPL-2.0-only
/// do_div() does a 64-by-32 division.
/// When the divisor is long, unsigned long, u64, or s64,
/// do_div() truncates it to 32 bits, this means it can test
/// non-zero and be truncated to 0 for division on 64bit platforms.
///
//# This makes an effort to find those inappropriate do_div() calls.
//
// Confidence: Moderate
// Copyright: (C) 2020 Wen Yang, Alibaba.
// Comments:
// Options: --no-includes --include-headers
virtual context
virtual org
virtual report
@initialize:python@
@@
def get_digit_type_and_value(str):
is_digit = False
value = 0
try:
if (str.isdigit()):
is_digit = True
value = int(str, 0)
elif (str.upper().endswith('ULL')):
is_digit = True
value = int(str[:-3], 0)
elif (str.upper().endswith('LL')):
is_digit = True
value = int(str[:-2], 0)
elif (str.upper().endswith('UL')):
is_digit = True
value = int(str[:-2], 0)
elif (str.upper().endswith('L')):
is_digit = True
value = int(str[:-1], 0)
elif (str.upper().endswith('U')):
is_digit = True
value = int(str[:-1], 0)
except Exception as e:
print('Error:',e)
is_digit = False
value = 0
finally:
return is_digit, value
def filter_out_safe_constants(str):
is_digit, value = get_digit_type_and_value(str)
if (is_digit):
if (value >= 0x100000000):
return True
else:
return False
else:
return True
def construct_warnings(suggested_fun):
msg="WARNING: do_div() does a 64-by-32 division, please consider using %s instead."
return msg % suggested_fun
@depends on context@
expression f;
long l: script:python() { filter_out_safe_constants(l) };
unsigned long ul : script:python() { filter_out_safe_constants(ul) };
u64 ul64 : script:python() { filter_out_safe_constants(ul64) };
s64 sl64 : script:python() { filter_out_safe_constants(sl64) };
@@
(
* do_div(f, l);
|
* do_div(f, ul);
|
* do_div(f, ul64);
|
* do_div(f, sl64);
)
@r depends on (org || report)@
expression f;
position p;
long l: script:python() { filter_out_safe_constants(l) };
unsigned long ul : script:python() { filter_out_safe_constants(ul) };
u64 ul64 : script:python() { filter_out_safe_constants(ul64) };
s64 sl64 : script:python() { filter_out_safe_constants(sl64) };
@@
(
do_div@p(f, l);
|
do_div@p(f, ul);
|
do_div@p(f, ul64);
|
do_div@p(f, sl64);
)
@script:python depends on org@
p << r.p;
ul << r.ul;
@@
coccilib.org.print_todo(p[0], construct_warnings("div64_ul"))
@script:python depends on org@
p << r.p;
l << r.l;
@@
coccilib.org.print_todo(p[0], construct_warnings("div64_long"))
@script:python depends on org@
p << r.p;
ul64 << r.ul64;
@@
coccilib.org.print_todo(p[0], construct_warnings("div64_u64"))
@script:python depends on org@
p << r.p;
sl64 << r.sl64;
@@
coccilib.org.print_todo(p[0], construct_warnings("div64_s64"))
@script:python depends on report@
p << r.p;
ul << r.ul;
@@
coccilib.report.print_report(p[0], construct_warnings("div64_ul"))
@script:python depends on report@
p << r.p;
l << r.l;
@@
coccilib.report.print_report(p[0], construct_warnings("div64_long"))
@script:python depends on report@
p << r.p;
sl64 << r.sl64;
@@
coccilib.report.print_report(p[0], construct_warnings("div64_s64"))
@script:python depends on report@
p << r.p;
ul64 << r.ul64;
@@
coccilib.report.print_report(p[0], construct_warnings("div64_u64"))