[PATCH] checkpatch: warn when formats use %Z and suggest %z

From: Joe Perches
Date: Mon Jan 09 2017 - 21:11:38 EST


From: Alexey Dobriyan <adobriyan@xxxxxxxxx>

vsnprintf extension %Z<foo> is non-standard C.
Suggest the use of %z instead.

Miscellanea:

o Correct the misuse of type string PRINTF_0xDECIMAL
type strings are supposed to be uppercase only.
Fix this and add tr/[a-z]/[A-Z] to the type check in case
I forget this again sometime in the future.
o Improve the mechanism to find these defects so all
3 current checks are done on the format string

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---

I'll assume Alexey is OK with this modification to the patch he created.

scripts/checkpatch.pl | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 99babcdf1dd8..89a7ad69d4fe 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1848,6 +1848,8 @@ my $prefix = '';
sub show_type {
my ($type) = @_;

+ $type =~ tr/[a-z]/[A-Z]/;
+
return defined $use_type{$type} if (scalar keys %use_type > 0);

return !defined $ignore_type{$type};
@@ -5179,24 +5181,27 @@ sub process {
"Consecutive strings are generally better as a single string\n" . $herecurr);
}

-# check for %L{u,d,i} and 0x%[udi] in strings
- my $string;
+# check for non-standard and hex prefixed decimal printf formats
+ my $show_L = 1; #don't show the same defect twice
+ my $show_Z = 1;
while ($line =~ /(?:^|")([X\t]*)(?:"|$)/g) {
- $string = substr($rawline, $-[1], $+[1] - $-[1]);
+ my $string = substr($rawline, $-[1], $+[1] - $-[1]);
$string =~ s/%%/__/g;
- if ($string =~ /(?<!%)%[\*\d\.\$]*L[udi]/) {
+ # check for %L
+ if ($show_L && $string =~ /%[\*\d\.\$]*L([diouxX])/) {
WARN("PRINTF_L",
- "\%Ld/%Lu are not-standard C, use %lld/%llu\n" . $herecurr);
- last;
+ "\%L$1 is non-standard C, use %ll$1\n" . $herecurr);
+ $show_L = 0;
}
# check for %Z
- if ($string =~ /(?<!%)%[\*\d\.\$]*Z[diouxX]/) {
+ if ($show_Z && $string =~ /%[\*\d\.\$]*Z([diouxX])/) {
WARN("PRINTF_Z",
- "%Z is non-standard C, use %z\n" . $herecurr);
- last;
+ "%Z$1 is non-standard C, use %z$1\n" . $herecurr);
+ $show_Z = 0;
}
- if ($string =~ /0x%[\*\d\.\$\Llzth]*[udi]/) {
- ERROR("PRINTF_0xDECIMAL",
+ # check for 0x<decimal>
+ if ($string =~ /0x%[\*\d\.\$\Llzth]*[diou]/) {
+ ERROR("PRINTF_0XDECIMAL",
"Prefixing 0x with decimal output is defective\n" . $herecurr);
}
}
--
2.10.0.rc2.1.g053435c