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| 1 | +eval '(exit $?0)' && eval 'exec perl -wST "$0" ${1+"$@"}' |
| 2 | + & eval 'exec perl -wST "$0" $argv:q' |
| 3 | + if 0; |
| 4 | +# Detect instances of "if (p) free (p);". |
| 5 | +# Likewise "if (p != 0)", "if (0 != p)", or with NULL; and with braces. |
| 6 | + |
| 7 | +my $VERSION = '2011-04-20 13:43'; # UTC |
| 8 | +# The definition above must lie within the first 8 lines in order |
| 9 | +# for the Emacs time-stamp write hook (at end) to update it. |
| 10 | +# If you change this file with Emacs, please let the write hook |
| 11 | +# do its job. Otherwise, update this string manually. |
| 12 | + |
| 13 | +# Copyright (C) 2008-2011 Free Software Foundation, Inc. |
| 14 | + |
| 15 | +# This program is free software: you can redistribute it and/or modify |
| 16 | +# it under the terms of the GNU General Public License as published by |
| 17 | +# the Free Software Foundation, either version 3 of the License, or |
| 18 | +# (at your option) any later version. |
| 19 | + |
| 20 | +# This program is distributed in the hope that it will be useful, |
| 21 | +# but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 22 | +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 23 | +# GNU General Public License for more details. |
| 24 | + |
| 25 | +# You should have received a copy of the GNU General Public License |
| 26 | +# along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 27 | + |
| 28 | +# Written by Jim Meyering |
| 29 | + |
| 30 | +use strict; |
| 31 | +use warnings; |
| 32 | +use Getopt::Long; |
| 33 | + |
| 34 | +(my $ME = $0) =~ s|.*/||; |
| 35 | + |
| 36 | +# use File::Coda; # http://meyering.net/code/Coda/ |
| 37 | +END { |
| 38 | + defined fileno STDOUT or return; |
| 39 | + close STDOUT and return; |
| 40 | + warn "$ME: failed to close standard output: $!\n"; |
| 41 | + $? ||= 1; |
| 42 | +} |
| 43 | + |
| 44 | +sub usage ($) |
| 45 | +{ |
| 46 | + my ($exit_code) = @_; |
| 47 | + my $STREAM = ($exit_code == 0 ? *STDOUT : *STDERR); |
| 48 | + if ($exit_code != 0) |
| 49 | + { |
| 50 | + print $STREAM "Try `$ME --help' for more information.\n"; |
| 51 | + } |
| 52 | + else |
| 53 | + { |
| 54 | + print $STREAM <<EOF; |
| 55 | +Usage: $ME [OPTIONS] FILE... |
| 56 | + |
| 57 | +Detect any instance in FILE of a useless "if" test before a free call, e.g., |
| 58 | +"if (p) free (p);". Any such test may be safely removed without affecting |
| 59 | +the semantics of the C code in FILE. Use --name=FOO --name=BAR to also |
| 60 | +detect free-like functions named FOO and BAR. |
| 61 | + |
| 62 | +OPTIONS: |
| 63 | + |
| 64 | + --list print only the name of each matching FILE (\\0-terminated) |
| 65 | + --name=N add name N to the list of \`free\'-like functions to detect; |
| 66 | + may be repeated |
| 67 | + |
| 68 | + --help display this help and exit |
| 69 | + --version output version information and exit |
| 70 | + |
| 71 | +Exit status: |
| 72 | + |
| 73 | + 0 one or more matches |
| 74 | + 1 no match |
| 75 | + 2 an error |
| 76 | + |
| 77 | +EXAMPLE: |
| 78 | + |
| 79 | +For example, this command prints all removable "if" tests before "free" |
| 80 | +and "kfree" calls in the linux kernel sources: |
| 81 | + |
| 82 | + git ls-files -z |xargs -0 $ME --name=kfree |
| 83 | + |
| 84 | +EOF |
| 85 | + } |
| 86 | + exit $exit_code; |
| 87 | +} |
| 88 | + |
| 89 | +sub is_NULL ($) |
| 90 | +{ |
| 91 | + my ($expr) = @_; |
| 92 | + return ($expr eq 'NULL' || $expr eq '0'); |
| 93 | +} |
| 94 | + |
| 95 | +{ |
| 96 | + sub EXIT_MATCH {0} |
| 97 | + sub EXIT_NO_MATCH {1} |
| 98 | + sub EXIT_ERROR {2} |
| 99 | + my $err = EXIT_NO_MATCH; |
| 100 | + |
| 101 | + my $list; |
| 102 | + my @name = qw(free); |
| 103 | + GetOptions |
| 104 | + ( |
| 105 | + help => sub { usage 0 }, |
| 106 | + version => sub { print "$ME version $VERSION\n"; exit }, |
| 107 | + list => \$list, |
| 108 | + 'name=s@' => \@name, |
| 109 | + ) or usage 1; |
| 110 | + |
| 111 | + # Make sure we have the right number of non-option arguments. |
| 112 | + # Always tell the user why we fail. |
| 113 | + @ARGV < 1 |
| 114 | + and (warn "$ME: missing FILE argument\n"), usage EXIT_ERROR; |
| 115 | + |
| 116 | + my $or = join '|', @name; |
| 117 | + my $regexp = qr/(?:$or)/; |
| 118 | + |
| 119 | + # Set the input record separator. |
| 120 | + # Note: this makes it impractical to print line numbers. |
| 121 | + $/ = '"'; |
| 122 | + |
| 123 | + my $found_match = 0; |
| 124 | + FILE: |
| 125 | + foreach my $file (@ARGV) |
| 126 | + { |
| 127 | + open FH, '<', $file |
| 128 | + or (warn "$ME: can't open `$file' for reading: $!\n"), |
| 129 | + $err = EXIT_ERROR, next; |
| 130 | + while (defined (my $line = <FH>)) |
| 131 | + { |
| 132 | + while ($line =~ |
| 133 | + /\b(if\s*\(\s*([^)]+?)(?:\s*!=\s*([^)]+?))?\s*\) |
| 134 | + # 1 2 3 |
| 135 | + (?: \s*$regexp\s*\((?:\s*\([^)]+\))?\s*([^)]+)\)\s*;| |
| 136 | + \s*\{\s*$regexp\s*\((?:\s*\([^)]+\))?\s*([^)]+)\)\s*;\s*\}))/sxg) |
| 137 | + { |
| 138 | + my $all = $1; |
| 139 | + my ($lhs, $rhs) = ($2, $3); |
| 140 | + my ($free_opnd, $braced_free_opnd) = ($4, $5); |
| 141 | + my $non_NULL; |
| 142 | + if (!defined $rhs) { $non_NULL = $lhs } |
| 143 | + elsif (is_NULL $rhs) { $non_NULL = $lhs } |
| 144 | + elsif (is_NULL $lhs) { $non_NULL = $rhs } |
| 145 | + else { next } |
| 146 | + |
| 147 | + # Compare the non-NULL part of the "if" expression and the |
| 148 | + # free'd expression, without regard to white space. |
| 149 | + $non_NULL =~ tr/ \t//d; |
| 150 | + my $e2 = defined $free_opnd ? $free_opnd : $braced_free_opnd; |
| 151 | + $e2 =~ tr/ \t//d; |
| 152 | + if ($non_NULL eq $e2) |
| 153 | + { |
| 154 | + $found_match = 1; |
| 155 | + $list |
| 156 | + and (print "$file\0"), next FILE; |
| 157 | + print "$file: $all\n"; |
| 158 | + } |
| 159 | + } |
| 160 | + } |
| 161 | + } |
| 162 | + continue |
| 163 | + { |
| 164 | + close FH; |
| 165 | + } |
| 166 | + |
| 167 | + $found_match && $err == EXIT_NO_MATCH |
| 168 | + and $err = EXIT_MATCH; |
| 169 | + |
| 170 | + exit $err; |
| 171 | +} |
| 172 | + |
| 173 | +my $foo = <<'EOF'; |
| 174 | +# The above is to *find* them. |
| 175 | +# This adjusts them, removing the unnecessary "if (p)" part. |
| 176 | + |
| 177 | +# FIXME: do something like this as an option (doesn't do braces): |
| 178 | +free=xfree |
| 179 | +git grep -l -z "$free *(" \ |
| 180 | + | xargs -0 useless-if-before-free -l --name="$free" \ |
| 181 | + | xargs -0 perl -0x3b -pi -e \ |
| 182 | + 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*(?:0|NULL))?\s*\)\s+('"$free"'\s*\((?:\s*\([^)]+\))?\s*\1\s*\)\s*;)/$2/s' |
| 183 | + |
| 184 | +# Use the following to remove redundant uses of kfree inside braces. |
| 185 | +# Note that -0777 puts perl in slurp-whole-file mode; |
| 186 | +# but we have plenty of memory, these days... |
| 187 | +free=kfree |
| 188 | +git grep -l -z "$free *(" \ |
| 189 | + | xargs -0 useless-if-before-free -l --name="$free" \ |
| 190 | + | xargs -0 perl -0777 -pi -e \ |
| 191 | + 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*(?:0|NULL))?\s*\)\s*\{\s*('"$free"'\s*\((?:\s*\([^)]+\))?\s*\1\s*\);)\s*\}[^\n]*$/$2/gms' |
| 192 | + |
| 193 | +Be careful that the result of the above transformation is valid. |
| 194 | +If the matched string is followed by "else", then obviously, it won't be. |
| 195 | + |
| 196 | +When modifying files, refuse to process anything other than a regular file. |
| 197 | +EOF |
| 198 | + |
| 199 | +## Local Variables: |
| 200 | +## mode: perl |
| 201 | +## indent-tabs-mode: nil |
| 202 | +## eval: (add-hook 'write-file-hooks 'time-stamp) |
| 203 | +## time-stamp-start: "my $VERSION = '" |
| 204 | +## time-stamp-format: "%:y-%02m-%02d %02H:%02M" |
| 205 | +## time-stamp-time-zone: "UTC" |
| 206 | +## time-stamp-end: "'; # UTC" |
| 207 | +## End: |
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