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checkhf: handle C++-style comments 

"tools/checkhf.pl epan/dissectors/packet-umts_fp.c" gave this error:

    Complex regular subexpression recursion limit (32766) exceeded at tools/checkhf.pl line 273.

This is caused by the comment "// ... Indicator's ..." which failed to
match the single-quoted string and caused "catastrophic backtracking".
Solution to fix this case is to disallow unescaped newlines (add "\n" to
the negated character class). Additionally, add logic to remove
C++-style comments for completeness.

Tested against all epan/dissectors/packet-*.c files, the only difference
in output is this umts_fp case, the running time has not regressed.

Change-Id: I7b43e01e1580acf831c0485513135b613bb02e8b
Reported-by: Joerg Mayer
Reviewed-on: https://code.wireshark.org/review/20965
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Michael Mann <mmann78@netscape.net>
This commit is contained in:
Peter Wu 2017-04-08 19:34:24 +02:00 committed by Michael Mann
parent 6d204e5152
commit f1751ef22f
1 changed files with 21 additions and 9 deletions
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30
tools/checkhf.pl
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@ -235,6 +235,18 @@ sub remove_blank_lines {
return;
}
sub get_quoted_str_regex {
# A regex which matches double-quoted strings.
# 's' modifier added so that strings containing a 'line continuation'
# ( \ followed by a new-line) will match.
my $double_quoted_str = qr{ (?: ["] (?: \\. | [^\"\\\n])* ["]) }xmso;
# A regex which matches single-quoted strings.
my $single_quoted_str = qr{ (?: ['] (?: \\. | [^\'\\\n])* [']) }xmso;
return qr{ $double_quoted_str | $single_quoted_str }xmso;
}
# ------------
# action: remove comments from input string
# arg: code_ref, filename
@ -250,6 +262,13 @@ sub remove_comments {
${$code_ref} =~ s{ $c_comment_regex } {}xmsog;
# Remove single-line C++-style comments. Be careful not to break up strings
# like "coap://", so match double quoted strings, single quoted characters,
# division operator and other characters before the actual "//" comment.
my $quoted_str = get_quoted_str_regex();
my $cpp_comment_regex = qr{ ^((?: $quoted_str | /(?!/) | [^'"/\n] )*) // .*$ }xm;
${$code_ref} =~ s{ $cpp_comment_regex } { $1 }xmg;
($debug == 1) && print "==> After Remove Comments: code: [$filename]\n${$code_ref}\n===<\n";
return;
@ -262,15 +281,8 @@ sub remove_comments {
sub remove_quoted_strings {
my ($code_ref, $filename) = @_;
# A regex which matches double-quoted strings.
# 's' modifier added so that strings containing a 'line continuation'
# ( \ followed by a new-line) will match.
my $double_quoted_str = qr{ (?: ["] (?: \\. | [^\"\\])* ["]) }xmso;
# A regex which matches single-quoted strings.
my $single_quoted_str = qr{ (?: ['] (?: \\. | [^\'\\])* [']) }xmso;
${$code_ref} =~ s{ $double_quoted_str | $single_quoted_str } {}xmsog;
my $quoted_str = get_quoted_str_regex();
${$code_ref} =~ s{ $quoted_str } {}xmsog;
($debug == 1) && print "==> After Remove quoted strings: code: [$filename]\n${$code_ref}\n===<\n";