diff options
Diffstat (limited to 'scripts/coccinelle/misc/do_div.cocci')
| -rw-r--r-- | scripts/coccinelle/misc/do_div.cocci | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/scripts/coccinelle/misc/do_div.cocci b/scripts/coccinelle/misc/do_div.cocci new file mode 100644 index 000000000..79db083c5 --- /dev/null +++ b/scripts/coccinelle/misc/do_div.cocci @@ -0,0 +1,155 @@ +// 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")) |