Diff for "roelkluin" - Linux Kernel Newbies

Differences between revisions 4 and 13 (spanning 9 versions)

Roel Kluin

I wrote a few tools to do a multiline (git) grep, see [wiki:roelkluin/cvars_howto cvars howto]. To use these tools you first source [wiki:roelkluin/cvars cvars] and then do the searches in your git directory.

Search for conditions that execute the same code in the if and else branches

gres -A40 "^ if \(" \
"if \(.8.\)
        (@branch)
else \9" | less

Search for switch cases that execute the same code.

gres -A40 "^ case@S[^:]*: $" \
"case@S[^:\n]*: \n
(([^\n]*[^:{[:space:]] \n|\{.8.\}){2,})
(case@S[^:\n]*: ([^\n]*[^:{[:space:]] \n|\{.8.\})*)*
case@S[^:\n]*:
\1
(case|default)@S[^:\n]*:" | less

Some functions' return codes should be audited, the scripts below searches for code sections where this lacks.

Z="request_region kmalloc vmalloc kzalloc scsi_register create_proc_entry"
for z in $Z; do
echo "---[ $z ]---"
gres -B1 -A20 "^((.* (@w) =)? (\( @V \** \) )*)? $z \(" \
"@Q2(\**@w) = (\**@w = )*(\( @V \** \) )* $z \(...\) ;.*
(return|[&|(]) (\1 [=\!]= NULL|\!? \1|NULL [=\!]= \1) [&|)?;]" \
"@Q2(\**@w = )+(\( @V \** \) )* $z \(...\) ;"
done | less

Z="request_irq register_netdev misc_register create_proc_profile kernel_thread do_fork"
for z in $Z; do
echo "---[ $z ]---"
gres -B1 -A20 "^((.* (@w) =)? (\( @V \** \) )*)? $z \(" \
"@Q2(\**@w) = (\**@w = )*(\( @V \** \) )* $z \(...\) ;.*
(return|[&|(]) (\1 (<|[\!>=]=) 0|\!? \1|0 (>|[\!<=]=) \1) [)&|?;]" \
"@Q2(\**@w = )+(\( @V \** \) )* $z \(...\) ;"
done | less

-  ⇤ ← Revision 4 as of 2009-09-08 22:47:39 → 
  Size: 2595
  Editor: d133062
  Comment:
+   ← Revision 13 as of 2010-01-20 01:31:31 → ⇥
  Size: 1590
  Editor: d133062
  Comment: a few more examples
-Deletions are marked like this.
+Additions are marked like this.
 Line 7:
+I wrote a few tools to do a multiline (git) grep, see [wiki:roelkluin/cvars_howto cvars howto]. To use these tools you first source [wiki:roelkluin/cvars cvars] and then do the searches in your git directory.

'''Search for conditions that execute the same code in the if and else branches'''
-Line 8:
+Line 11:
-#!/bin/bash
+gres -A40 "^ if \(" \
"if \(.8.\)
 (@branch)
else \9" | less
}}}
-Line 10:
+Line 17:
-# blank_it: replaces spaces with bracket expressions to match
# optional/obligatory spaces for usage with egrep.
bli2()
{
local int="[[:digit:]]"
local hex="[[:xdigit:]]"
local up_="[[:upper:]_]"
local al_="[[:alpha:]_]"
local AN_="[[:upper:][:digit:]_]"
local an_="[[:alnum:]_]"
local sp="[[:space:]]"
local V="$al_+$an_*"
+'''Search for switch cases that execute the same code.'''
{{{
gres -A40 "^ case@S[^:]*: $" \
"case@S[^:\n]*: \n
(([^\n]*[^:{[:space:]] \n|\{.8.\}){2,})
(case@S[^:\n]*: ([^\n]*[^:{[:space:]] \n|\{.8.\})*)*
case@S[^:\n]*:
\1
(case|default)@S[^:\n]*:" | less
}}}
-Line 23:
+Line 28:
-local l="$1"
l="${l//@V/$V}"                 # variable/function/struct name
l="${l//@Q2/[^[:alnum:]_>.]}"   # 1 char left of variable/function/struct name
l="${l//@Q/[^[:alnum:]_]}"      # 1 char right of variable/function/struct name
l="${l//@d/($int+[uUlLfF]?|$int+[uU]?[lL][lL]?|0x$hex+|$int+[lL][lL][uU]|$int*\.$int+[fF]?)}"   # a number
l="${l//@K/$up_+$AN_*}"         # an definition or macro name (uppercase)
l="${l//@s/$sp*}"               # optional space
l="${l//@S/$sp+}"               # obligatory space
l="${l//@w/($V|\.|->|\[$sp*[^][]+$sp*\]|\($sp*[^)(]*$sp*\))+}"          # a variable/array/member/unnested function or macro
l="${l//\\\(...\\\)/\([^()]*(\([^()]*(\([^()]*\)[^()]*)*\)[^()]*)*\)}"  # nested parentheses, 2 backrefs
l="$(echo "$l" | sed -r "s/\\\\\{\.\.\.\\\\\}/\\\\\{\[^\}\{\]*(\\\\\{\[^\}\{\]*(\\\\\{\[^\}\{\]*\\\\\}\[^\}\{\]*)*\\\\\}\[^\}\{\]*)*\\\\\}/g")" # nested curly brackets, 2 backrefs
 echo "$l" | sed -r "
:a
s/($an_)$sp+($an_)/\1$sp+\2/g
s/(\[\[:space:\]\]\*)*$sp+/$sp*/g
$!{
 N
 ba
}
"
}
+'''Some functions' return codes should be audited, the scripts below searches for code sections where this lacks.'''
{{{
Z="request_region kmalloc vmalloc kzalloc scsi_register create_proc_entry"
for z in $Z; do
echo "---[ $z ]---"
gres -B1 -A20 "^((.* (@w) =)? (\( @V \** \) )*)? $z \(" \
"@Q2(\**@w) = (\**@w = )*(\( @V \** \) )* $z \(...\) ;.*
(return|[&|(]) (\1 [=\!]= NULL|\!? \1|NULL [=\!]= \1) [&|)?;]" \
"@Q2(\**@w = )+(\( @V \** \) )* $z \(...\) ;"
done | less
-Line 45:
+Line 39:
-# echo a sed script to catch $1 from multiline grep and filter out $2.
# e.g. grep -E -n -H -B1 -A10 "foo" ~/file | sed -n -r "$(ecsed "foo" "foo.*bar")"
ecsed()
{
local sp="[[:space:]]";         # space
local ns="[^[:space:]]";        # no space
local bol="$ns*[:-][0-9]+[:-]"  # begin of line
 [ -n "$2" ] && not="/$(bli2 "$2")/b"
echo ":start
/(--|$bol}$s)$/!{
N
b start
}
s/$sp*\/\*+([^*]*|\*[^\/])*\*+\// /g    # remove C style comment
s/(\/\/[^\n]*)?\n$bol/\n/g              # remove C99 comment
$not
s/^($ns*)[:-]([0-9]+)[:-]/---[ vi \1 +\2 ]---\n/
s/\n--$//
/$(bli2 "$1")/p"
}
+Z="request_irq register_netdev misc_register create_proc_profile kernel_thread do_fork"
for z in $Z; do
echo "---[ $z ]---"
gres -B1 -A20 "^((.* (@w) =)? (\( @V \** \) )*)? $z \(" \
"@Q2(\**@w) = (\**@w = )*(\( @V \** \) )* $z \(...\) ;.*
(return|[&|(]) (\1 (<|[\!>=]=) 0|\!? \1|0 (>|[\!<=]=) \1) [)&|?;]" \
"@Q2(\**@w = )+(\( @V \** \) )* $z \(...\) ;"
done | less
-Line 66:
+Line 48:
-To use, save and source this file. An example script below:
search for kmallocing of variables without test of kmalloc success.
goto your git Linux kernel directory and paste into the console:

{{{
em='!'
z="kmalloc"
git grep -E -n -B3 -A20 "$(bli2 "@Q2$z \(")" | sed -n -r "$(ecsed \
"@Q2(@w) = (\(...\) )* $z \(...\) ;" \
"@Q2(@w) = (@w = )*(\(...\) )* $z \(...\) ;([^\n]*\n)*
[^\n]*([&|(]|return) (\1 [=$em]= NULL|$em? \1|NULL [=$em]= \1) [&|)?]" \
)" | less
em='!'
}}}