1 Copyright 2010 Nicolas Palix <npalix@diku.dk>
2 Copyright 2010 Julia Lawall <julia@diku.dk>
3 Copyright 2010 Gilles Muller <Gilles.Muller@lip6.fr>
9 The semantic patches included in the kernel use the 'virtual rule'
10 feature which was introduced in Coccinelle version 0.1.11.
12 Coccinelle (>=0.2.0) is available through the package manager
13 of many distributions, e.g. :
17 - Ubuntu (>=10.04 Lucid Lynx)
24 You can get the latest version released from the Coccinelle homepage at
25 http://coccinelle.lip6.fr/
27 Information and tips about Coccinelle are also provided on the wiki
28 pages at http://cocci.ekstranet.diku.dk/wiki/doku.php
30 Once you have it, run the following command:
35 as a regular user, and install it with
39 The semantic patches in the kernel will work best with Coccinelle version
40 0.2.4 or later. Using earlier versions may incur some parse errors in the
41 semantic patch code, but any results that are obtained should still be
44 Using Coccinelle on the Linux kernel
45 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
47 A Coccinelle-specific target is defined in the top level
48 Makefile. This target is named 'coccicheck' and calls the 'coccicheck'
49 front-end in the 'scripts' directory.
51 Four modes are defined: patch, report, context, and org. The mode to
52 use is specified by setting the MODE variable with 'MODE=<mode>'.
54 'patch' proposes a fix, when possible.
56 'report' generates a list in the following format:
57 file:line:column-column: message
59 'context' highlights lines of interest and their context in a
60 diff-like style.Lines of interest are indicated with '-'.
62 'org' generates a report in the Org mode format of Emacs.
64 Note that not all semantic patches implement all modes. For easy use
65 of Coccinelle, the default mode is "chain" which tries the previous
66 modes in the order above until one succeeds.
68 To make a report for every semantic patch, run the following command:
70 make coccicheck MODE=report
72 NB: The 'report' mode is the default one.
74 To produce patches, run:
76 make coccicheck MODE=patch
79 The coccicheck target applies every semantic patch available in the
80 sub-directories of 'scripts/coccinelle' to the entire Linux kernel.
82 For each semantic patch, a commit message is proposed. It gives a
83 description of the problem being checked by the semantic patch, and
84 includes a reference to Coccinelle.
86 As any static code analyzer, Coccinelle produces false
87 positives. Thus, reports must be carefully checked, and patches
91 Using Coccinelle with a single semantic patch
92 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
94 The optional make variable COCCI can be used to check a single
95 semantic patch. In that case, the variable must be initialized with
96 the name of the semantic patch to apply.
100 make coccicheck COCCI=<my_SP.cocci> MODE=patch
102 make coccicheck COCCI=<my_SP.cocci> MODE=report
105 Using Coccinelle on (modified) files
106 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
108 To apply Coccinelle on a file basis, instead of a directory basis, the
109 following command may be used:
111 make C=1 CHECK="scripts/coccicheck"
113 To check only newly edited code, use the value 2 for the C flag, i.e.
115 make C=2 CHECK="scripts/coccicheck"
117 This runs every semantic patch in scripts/coccinelle by default. The
118 COCCI variable may additionally be used to only apply a single
119 semantic patch as shown in the previous section.
121 The "chain" mode is the default. You can select another one with the
122 MODE variable explained above.
124 In this mode, there is no information about semantic patches
125 displayed, and no commit message proposed.
128 Proposing new semantic patches
129 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
131 New semantic patches can be proposed and submitted by kernel
132 developers. For sake of clarity, they should be organized in the
133 sub-directories of 'scripts/coccinelle/'.
136 Detailed description of the 'report' mode
137 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
139 'report' generates a list in the following format:
140 file:line:column-column: message
146 make coccicheck MODE=report COCCI=scripts/coccinelle/api/err_cast.cocci
148 will execute the following part of the SmPL script.
151 @r depends on !context && !patch && (org || report)@
156 ERR_PTR@p(PTR_ERR(x))
158 @script:python depends on report@
163 msg="ERR_CAST can be used with %s" % (x)
164 coccilib.report.print_report(p[0], msg)
167 This SmPL excerpt generates entries on the standard output, as
170 /home/user/linux/crypto/ctr.c:188:9-16: ERR_CAST can be used with alg
171 /home/user/linux/crypto/authenc.c:619:9-16: ERR_CAST can be used with auth
172 /home/user/linux/crypto/xts.c:227:9-16: ERR_CAST can be used with alg
175 Detailed description of the 'patch' mode
176 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
178 When the 'patch' mode is available, it proposes a fix for each problem
184 make coccicheck MODE=patch COCCI=scripts/coccinelle/api/err_cast.cocci
186 will execute the following part of the SmPL script.
189 @ depends on !context && patch && !org && !report @
193 - ERR_PTR(PTR_ERR(x))
197 This SmPL excerpt generates patch hunks on the standard output, as
200 diff -u -p a/crypto/ctr.c b/crypto/ctr.c
201 --- a/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200
202 +++ b/crypto/ctr.c 2010-06-03 23:44:49.000000000 +0200
203 @@ -185,7 +185,7 @@ static struct crypto_instance *crypto_ct
204 alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
205 CRYPTO_ALG_TYPE_MASK);
207 - return ERR_PTR(PTR_ERR(alg));
208 + return ERR_CAST(alg);
210 /* Block size must be >= 4 bytes. */
213 Detailed description of the 'context' mode
214 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
216 'context' highlights lines of interest and their context
217 in a diff-like style.
219 NOTE: The diff-like output generated is NOT an applicable patch. The
220 intent of the 'context' mode is to highlight the important lines
221 (annotated with minus, '-') and gives some surrounding context
222 lines around. This output can be used with the diff mode of
223 Emacs to review the code.
228 make coccicheck MODE=context COCCI=scripts/coccinelle/api/err_cast.cocci
230 will execute the following part of the SmPL script.
233 @ depends on context && !patch && !org && !report@
237 * ERR_PTR(PTR_ERR(x))
240 This SmPL excerpt generates diff hunks on the standard output, as
243 diff -u -p /home/user/linux/crypto/ctr.c /tmp/nothing
244 --- /home/user/linux/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200
246 @@ -185,7 +185,6 @@ static struct crypto_instance *crypto_ct
247 alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
248 CRYPTO_ALG_TYPE_MASK);
250 - return ERR_PTR(PTR_ERR(alg));
252 /* Block size must be >= 4 bytes. */
255 Detailed description of the 'org' mode
256 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
258 'org' generates a report in the Org mode format of Emacs.
263 make coccicheck MODE=org COCCI=scripts/coccinelle/api/err_cast.cocci
265 will execute the following part of the SmPL script.
268 @r depends on !context && !patch && (org || report)@
273 ERR_PTR@p(PTR_ERR(x))
275 @script:python depends on org@
280 msg="ERR_CAST can be used with %s" % (x)
281 msg_safe=msg.replace("[","@(").replace("]",")")
282 coccilib.org.print_todo(p[0], msg_safe)
285 This SmPL excerpt generates Org entries on the standard output, as
288 * TODO [[view:/home/user/linux/crypto/ctr.c::face=ovl-face1::linb=188::colb=9::cole=16][ERR_CAST can be used with alg]]
289 * TODO [[view:/home/user/linux/crypto/authenc.c::face=ovl-face1::linb=619::colb=9::cole=16][ERR_CAST can be used with auth]]
290 * TODO [[view:/home/user/linux/crypto/xts.c::face=ovl-face1::linb=227::colb=9::cole=16][ERR_CAST can be used with alg]]