demos/unsigned.txt

   1 From 12o3l@tiscali.nl Fri Apr 18 18:13:39 2008
   2 Date: Fri, 18 Apr 2008 18:15:06 +0200
   3 From: Roel Kluin <12o3l@tiscali.nl>
   4 To: kernel-janitors@vger.kernel.org, kernelnewbies-bounce@nl.linux.org
   5 Subject: script to find incorrect tests on unsigneds
   6
   7 A bash script to find incorrect tests on unsigned values. for instance:
   8
   9 unsigned int i;
  10 ...
  11 i = neg_ret_function();
  12 ...
  13 if (i < 0) ...
  14
  15 #!/bin/bash
  16 # (c) roel kluin 2008 GPL v2
  17 #
  18 # TODO: make this working also for
  19 #                              ... $unsigned_var == $signed_var ...
  20 #                              ... $unsigned_var == \(-POSITIVE_DEF\|NEGATIVE_DEF\) ...
  21 #                              ... ( $unsigned_var [+*/%^&~-]?= ... ) < 0 ...
  22
  23 # a number
  24 int="[0-9]"
  25 hex="[a-f0-9]"
  26 hEx="[A-Fa-f0-9]"
  27 HEX="[A-F0-9]"
  28 upp="[A-Z]"
  29 up_="[A-Z_]"
  30 low="[a-z0-9]"
  31 lo_="[a-z0-9_]"
  32 alp="[A-Za-z]"
  33 al_="[A-Za-z_]"
  34 ALN="[A-Z0-9]"
  35 AN_="[A-Z0-9_]"
  36 aln="[A-Za-z0-9]"
  37 an_="[A-Za-z0-9_]"
  38 # to match something like 1ul, floats or hexes as well:
  39 D="$int*\.\?$int\+x\?$hex*[uUlL]\{0,3\}[fF]\?"
  40
  41 # more strict and catches it (costs one backreference for (git-)grep)
  42 d="\($int\+[uUlLfF]\?\|$int\+[uU]\?[lL][lL]\?\|0x$hex\+\|0x$HEX\+\|$i\+[lL][lL][uU]\|$i*\.$i\+[fF]\?\)"
  43
  44 # capital: can be used to catch a definition or config option
  45 K="$UP_\+$AN_*";
  46
  47 # can be used for a variable/function name:
  48 V="$an_\+$an_*"
  49
  50 # works the same as above, but also for members and arrays: one backreference
  51 # is more strict
  52 W="$V\(\[$s$V$s\]\|\[$s$D$s\]\|\.$V\|->$V\)*"
  53 # catches it at once (less strict)
  54 w="\($V\|${V}\[$s$an_*${s}\]\|$V\.\|$V->\)\+"
  55
  56 # seperators:
  57 s="[[:space:]]*";
  58 S="[[:space:]]\+"
  59
  60 # useful to delimit a variable name:
  61 Q="[^[:alnum:]_]"
  62
  63 # match the end of the line, including comments: one backreference (but at eol)
  64 cendl="$s\(\/[\*\/].*\)\?$"
  65
  66 # match something that is not comment, string or character: 2 backreferences
  67 ccode="\([^\/\"']*\|\/[^\*\/]\|\/\*\([^\*]*\|\**[^\/\*]\)*\*\+\/\|'[^']*'\|\"[^\"]*\"\)*"
  68
  69 # resp function open and end (only works when indentation is correct.
  70 fo="^[\{]$cendl"
  71 fe="^[\}]$cendl"
  72 se="^[\}];$cendl"
  73
  74 # to match nested parentheses
  75 nps="[^()]*"
  76 nstdps="\(($nps\(($nps\(($nps\(($nps\(($nps)$nps\)*)$nps\)*)$nps\)*)$nps\)*)$nps\)*"
  77
  78
  79 # first determine unsigned typedefs
  80 arr="\(\[[^\]]*\]$s\)*"
  81 attr="__attribute__$s(([^;]*))"
  82 utype="${s}typedef${S}unsigned$S\($V$S\)*"
  83 uns="unsigned$(
  84 git-grep "^$utype\($V$s$arr\|$attr$S$V$s$arr\|$V$s$arr$S$attr\)$s;$cendl" | sed -n "s/^[^.]*\.[hc]:$utype\(\($V\)$s$arr\|$attr$S\($V\)$s$arr\|\($V\)$s$arr$S$attr\)$s;$cendl/\\\\|\3\5\7/p" | sort | uniq | tr -d "\n")"
  85
  86 # define left and right operators
  87 # to decrease the number backrefences, these are assigned in loops
  88 opl=
  89 for op in "[;,|^?:(]" "[\!+*/%&|~^-]=" ">>=" "<<=" "\[" "&&" "$an_$s&"; do
  90  opl="$opl$op\|$op$s++\|$op$s--\|"
  91 done
  92 opl="\(${opl%|})"
  93 opr=
  94 for op in "[;,&|^?:)]" "[\!+*/%&|~^<>-]=" ">>=" "<<=" ">[^>]" "<[^<]" "\]"; do
  95  opr="$opr$op\|$op$s++\|$op$s--\|"
  96 done
  97 opr="\(${opr%|})"
  98
  99 # string catches invalid comparison
 100 q1="$opl$s\($w$s\(>=${s}0\|<${s}0\|[><\!=]=$s-$s$D\|[<>]$s-$s$D\)\|\(0$s>\|0$s<=\|-$s$D${s}[><\!=]=\|-$s$D${s}[<>]\)$s$w\)$s$opr"
 101
 102 start=0
 103 end=$(echo $uns | tr -cd "|" | wc -c)
 104
 105 # main function
 106 while [ $start -lt $end ]; do
 107   # we match 30 typedefs at a time
 108   tuns="$(echo $uns | cut -d "\\" -f$start-$(($start+29)))"
 109
 110   # catch candidate files
 111   for f in $(git-grep -l "^\(${ccode}[,;]$s\)\?\($tuns\)$S" | grep "[^.]*\.[ch]" | xargs grep -l "$q1"); do
 112     for n in $(sed -n "/^.*$q1/=" $f); do # lines
 113       for v in $(sed -n "${n}s/^.*$q1.*$/\3\6/p" $f); do
 114         # n2 = wine there
 115         head -n$n $f | tac | sed -n "/^[{]/q; /^\(.*$Q\)\?\($tuns\)$S\($V$S\)*$v$Q.*$/=" | while read n2;
 116         do
 117           echo "# --- invalid test on unsigned variable '$v' --- #"
 118           echo "vi $f +$n2 # unsigned declaration"
 119           echo "vi $f +$n # invalid test"
 120         done
 121       done
 122     done
 123   done
 124   start=$(($start+30))
 125 done | less
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