Merge branch 'kbuild/coccinelle' into kbuild/misc

Copyright 2010 Nicolas Palix <npalix@diku.dk>

Copyright 2010 Julia Lawall <julia@diku.dk>

Copyright 2010 Gilles Muller <Gilles.Muller@lip6.fr>

 Getting Coccinelle

~~~~~~~~~~~~~~~~~~~~

The semantic patches included in the kernel use the 'virtual rule'

feature which was introduced in Coccinelle version 0.1.11.

Coccinelle (>=0.2.0) is available through the package manager

of many distributions, e.g. :

 - Debian (>=squeeze)

 - Fedora (>=13)

 - Ubuntu (>=10.04 Karmic Koala)

 - OpenSUSE

 - Arch Linux

 - NetBSD

 - FreeBSD

You can get the latest version released from the Coccinelle homepage at

http://coccinelle.lip6.fr/

Once you have it, run the following command:

     	./configure

        make

as a regular user, and install it with

        sudo make install

 Using Coccinelle on the Linux kernel

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A Coccinelle-specific target is defined in the top level

Makefile. This target is named 'coccicheck' and calls the 'coccicheck'

front-end in the 'scripts' directory.

Four modes are defined: report, patch, context, and org. The mode to

use is specified by setting the MODE variable with 'MODE=<mode>'.

'report' generates a list in the following format:

  file:line:column-column: message

'patch' proposes a fix, when possible.

'context' highlights lines of interest and their context in a

diff-like style.Lines of interest are indicated with '-'.

'org' generates a report in the Org mode format of Emacs.

Note that not all semantic patches implement all modes.

To make a report for every semantic patch, run the following command:

	make coccicheck MODE=report

NB: The 'report' mode is the default one.

To produce patches, run:

	make coccicheck MODE=patch

The coccicheck target applies every semantic patch available in the

subdirectories of 'scripts/coccinelle' to the entire Linux kernel.

For each semantic patch, a changelog message is proposed.  It gives a

description of the problem being checked by the semantic patch, and

includes a reference to Coccinelle.

As any static code analyzer, Coccinelle produces false

positives. Thus, reports must be carefully checked, and patches

reviewed.

 Using Coccinelle with a single semantic patch

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The optional make variable COCCI can be used to check a single

semantic patch. In that case, the variable must be initialized with

the name of the semantic patch to apply.

For instance:

	make coccicheck COCCI=<my_SP.cocci> MODE=patch

or

	make coccicheck COCCI=<my_SP.cocci> MODE=report

 Proposing new semantic patches

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

New semantic patches can be proposed and submitted by kernel

developers. For sake of clarity, they should be organized in the

subdirectories of 'scripts/coccinelle/'.

 Detailed description of the 'report' mode

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

'report' generates a list in the following format:

  file:line:column-column: message

Example:

Running

	make coccicheck MODE=report COCCI=scripts/coccinelle/err_cast.cocci

will execute the following part of the SmPL script.

<smpl>

@r depends on !context && !patch && (org || report)@

expression x;

position p;

@@

 ERR_PTR@p(PTR_ERR(x))

@script:python depends on report@

p << r.p;

x << r.x;

@@

msg="ERR_CAST can be used with %s" % (x)

coccilib.report.print_report(p[0], msg)

</smpl>

This SmPL excerpt generates entries on the standard output, as

illustrated below:

/home/user/linux/crypto/ctr.c:188:9-16: ERR_CAST can be used with alg

/home/user/linux/crypto/authenc.c:619:9-16: ERR_CAST can be used with auth

/home/user/linux/crypto/xts.c:227:9-16: ERR_CAST can be used with alg

 Detailed description of the 'patch' mode

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When the 'patch' mode is available, it proposes a fix for each problem

identified.

Example:

Running

	make coccicheck MODE=patch COCCI=scripts/coccinelle/err_cast.cocci

will execute the following part of the SmPL script.

<smpl>

@ depends on !context && patch && !org && !report @

expression x;

@@

- ERR_PTR(PTR_ERR(x))

+ ERR_CAST(x)

</smpl>

This SmPL excerpt generates patch hunks on the standard output, as

illustrated below:

diff -u -p a/crypto/ctr.c b/crypto/ctr.c

--- a/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200

+++ b/crypto/ctr.c 2010-06-03 23:44:49.000000000 +0200

@@ -185,7 +185,7 @@ static struct crypto_instance *crypto_ct

 	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,

 				  CRYPTO_ALG_TYPE_MASK);

 	if (IS_ERR(alg))

-		return ERR_PTR(PTR_ERR(alg));

+		return ERR_CAST(alg);

 	/* Block size must be >= 4 bytes. */

 	err = -EINVAL;

 Detailed description of the 'context' mode

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

'context' highlights lines of interest and their context

in a diff-like style.

NOTE: The diff-like output generated is NOT an applicable patch. The

      intent of the 'context' mode is to highlight the important lines

      (annotated with minus, '-') and gives some surrounding context

      lines around. This output can be used with the diff mode of

      Emacs to review the code.

Example:

Running

	make coccicheck MODE=context COCCI=scripts/coccinelle/err_cast.cocci

will execute the following part of the SmPL script.

<smpl>

@ depends on context && !patch && !org && !report@

expression x;

@@

* ERR_PTR(PTR_ERR(x))

</smpl>

This SmPL excerpt generates diff hunks on the standard output, as

illustrated below:

diff -u -p /home/user/linux/crypto/ctr.c /tmp/nothing

--- /home/user/linux/crypto/ctr.c	2010-05-26 10:49:38.000000000 +0200

+++ /tmp/nothing

@@ -185,7 +185,6 @@ static struct crypto_instance *crypto_ct

 	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,

 				  CRYPTO_ALG_TYPE_MASK);

 	if (IS_ERR(alg))

-		return ERR_PTR(PTR_ERR(alg));

 	/* Block size must be >= 4 bytes. */

 	err = -EINVAL;

 Detailed description of the 'org' mode

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

'org' generates a report in the Org mode format of Emacs.

Example:

Running

	make coccicheck MODE=org COCCI=scripts/coccinelle/err_cast.cocci

will execute the following part of the SmPL script.

<smpl>

@r depends on !context && !patch && (org || report)@

expression x;

position p;

@@

 ERR_PTR@p(PTR_ERR(x))

@script:python depends on org@

p << r.p;

x << r.x;

@@

msg="ERR_CAST can be used with %s" % (x)

msg_safe=msg.replace("[","@(").replace("]",")")

coccilib.org.print_todo(p[0], msg_safe)

</smpl>

This SmPL excerpt generates Org entries on the standard output, as

illustrated below:

* TODO [[view:/home/user/linux/crypto/ctr.c::face=ovl-face1::linb=188::colb=9::cole=16][ERR_CAST can be used with alg]]

* TODO [[view:/home/user/linux/crypto/authenc.c::face=ovl-face1::linb=619::colb=9::cole=16][ERR_CAST can be used with auth]]

* TODO [[view:/home/user/linux/crypto/xts.c::face=ovl-face1::linb=227::colb=9::cole=16][ERR_CAST can be used with alg]]

S:	Supported

F:	drivers/platform/x86/classmate-laptop.c

COCCINELLE/Semantic Patches (SmPL)

M:	Julia Lawall <julia@diku.dk>

M:	Gilles Muller <Gilles.Muller@lip6.fr>

M:	Nicolas Palix <npalix@diku.dk>

L:	cocci@diku.dk (moderated for non-subscribers)

W:	http://coccinelle.lip6.fr/

S:	Supported

F:	scripts/coccinelle/

F:	scripts/coccicheck

CODA FILE SYSTEM

M:	Jan Harkes <jaharkes@cs.cmu.edu>

M:	coda@cs.cmu.edu

# of make so .config is not included in this case either (for *config).

no-dot-config-targets := clean mrproper distclean \

			 cscope TAGS tags help %docs check% \

			 cscope TAGS tags help %docs check% coccicheck \

			 include/linux/version.h headers_% \

			 kernelrelease kernelversion

	@echo  '  includecheck    - Check for duplicate included header files'

	@echo  '  export_report   - List the usages of all exported symbols'

	@echo  '  headers_check   - Sanity check on exported headers'

	@echo  '  headerdep       - Detect inclusion cycles in headers'; \

	 echo  ''

	@echo  '  headerdep       - Detect inclusion cycles in headers'

	@$(MAKE) -f $(srctree)/scripts/Makefile.help checker-help

	@echo  ''

	@echo  'Kernel packaging:'

	@$(MAKE) $(build)=$(package-dir) help

	@echo  ''

		-name '*.[hcS]' -type f -print | sort \

		| xargs $(PERL) -w $(srctree)/scripts/checkversion.pl

coccicheck:

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@

namespacecheck:

	$(PERL) $(srctree)/scripts/namespace.pl

checker-help:

	@echo  '  coccicheck      - Check with Coccinelle.'

#!/bin/sh

SPATCH="`which ${SPATCH:=spatch}`"

if [ ! -x "$SPATCH" ]; then

    echo 'spatch is part of the Coccinelle project and is available at http://coccinelle.lip6.fr/'

    exit 1

fi

if [ "$MODE" = "" ] ; then

    echo 'You have not explicitly specify the mode to use. Fallback to "report".'

    echo 'You can specify the mode with "make coccicheck MODE=<mode>"'

    echo 'Available modes are: report, patch, context, org'

    MODE="report"

fi

echo ''

echo 'Please check for false positives in the output before submitting a patch.'

echo 'When using "patch" mode, carefully review the patch before submitting it.'

echo ''

function coccinelle {

    COCCI="$1"

    DIR="$2"

    OPT=`grep "Option" $COCCI | cut -d':' -f2`

    FILE=`echo $COCCI | sed "s|$DIR/||"`

    echo "Processing `basename $COCCI` with option(s) \"$OPT\""

    echo 'Message example to submit a patch:'

    sed -e '/\/\/\//!d' -e 's|^///||' $COCCI

    echo ' The semantic patch that makes this change is available'

    echo " in $FILE."

    echo ''

    echo ' More information about semantic patching is available at'

    echo ' http://coccinelle.lip6.fr/'

    echo ''

#   The option '-parse_cocci' can be used to syntaxically check the SmPL files.

#

#    $SPATCH -D $MODE -very_quiet -parse_cocci $COCCI $OPT > /dev/null

    $SPATCH -D $MODE -very_quiet -sp_file $COCCI $OPT -dir $DIR

}

if [ "$COCCI" = "" ] ; then

    for f in `find $srctree/scripts/coccinelle/ -name '*.cocci' -type f | sort`; do

	coccinelle $f $srctree;

    done

else

    coccinelle $COCCI $srctree

fi