[Cocci] how to make substitutions at the end of the function, vs. the end of the block ?
Hi all,
I work on the VPP project (http://fd.io/ - open source software
dataplane), and yesterday tried to use coccinelle to make a relatively
non-trivial change
as in the mail https://lists.fd.io/g/vpp-dev/message/17532 - it seemed
to be a very good candidate - boring enough to be painful to do by
hand, complex enough to make sed inadequate for it.
I came up with this semantic patch:
@ detect_func @
identifier CLI_FN, AVM, AIN, ACMD;
fresh identifier LAIN = "line_" ## AIN;
statement S1;
typedef clib_error_t, vlib_main_t, unformat_input_t, vlib_cli_command_t;
@@
static clib_error_t *CLI_FN (vlib_main_t * AVM, unformat_input_t *
AIN, vlib_cli_command_t * ACMD)
{
+ clib_error_t *e = 0;
+ unformat_input_t *LAIN;
...
+ if (!unformat_user (AIN, unformat_line_input, LAIN)) {
+return 0;
+ }
+
- while (unformat_check_input (AIN) != UNFORMAT_END_OF_INPUT)
+ while (unformat_check_input (LAIN) != UNFORMAT_END_OF_INPUT)
S1
<...
- return ERR;
+ e = ERR;
+ goto done;
...>
+done:
+ unformat_free(LAIN);
+ return e;
}
I attempt to run it on this test file:
ubuntu@vpp-dev:~$ cat ~/test.c
static clib_error_t *
syn_filter_enable_disable_command_fn (vlib_main_t * vm,
unformat_input_t * input,
vlib_cli_command_t * cmd)
{
vnet_main_t *vnm = vnet_get_main ();
u32 sw_if_index = ~0;
int enable_disable = 1;
int rv;
while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
{
if (unformat (input, "disable"))
enable_disable = 0;
else if (unformat (input, "%U", unformat_vnet_sw_interface,
vnm, &sw_if_index))
;
else
break;
}
if (sw_if_index == ~0)
return clib_error_return (0, "Please specify an interface...");
rv = syn_filter_enable_disable (sw_if_index, enable_disable);
switch (rv)
{
case 0:
break;
case VNET_API_ERROR_INVALID_SW_IF_INDEX:
return clib_error_return
(0, "Invalid interface, only works on physical ports");
break;
case VNET_API_ERROR_UNIMPLEMENTED:
return clib_error_return (0,
"Device driver doesn't support redirection");
break;
case VNET_API_ERROR_INVALID_VALUE:
return clib_error_return (0, "feature arc not found");
case VNET_API_ERROR_INVALID_VALUE_2:
return clib_error_return (0, "feature node not found");
default:
return clib_error_return (0, "syn_filter_enable_disable returned %d",
rv);
}
return 0;
}
ubuntu@vpp-dev:~$
However, when I run it, the "done: " label, etc. gets inserted twice:
ubuntu@vpp-dev:~$ spatch --sp-file /tmp/rules.sp
--allow-inconsistent-paths ~/test.c
init_defs_builtins: /usr/bin/../lib/coccinelle/standard.h
HANDLING: /home/ubuntu/test.c
diff =
--- /home/ubuntu/test.c
+++ /tmp/cocci-output-56896-8f35c5-test.c
@@ -3,12 +3,18 @@ syn_filter_enable_disable_command_fn (vl
unformat_input_t * input,
vlib_cli_command_t * cmd)
{
+ clib_error_t *e = 0;
+ unformat_input_t *line_input;
vnet_main_t *vnm = vnet_get_main ();
u32 sw_if_index = ~0;
int enable_disable = 1;
int rv;
- while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ if (!unformat_user(input, unformat_line_input, line_input)) {
+ return 0;
+ }
+
+while (unformat_check_input(line_input) != UNFORMAT_END_OF_INPUT)
{
if (unformat (input, "disable"))
enable_disable = 0;
@@ -48,6 +54,12 @@ syn_filter_enable_disable_command_fn (vl
default:
return clib_error_return (0, "syn_filter_enable_disable returned %d",
rv);
-}
+done:
+ unformat_free(line_input);
+ return e;
+ }
return 0;
+done:
+ unformat_free(line_input);
+ return e;
}
ubuntu@vpp-dev:~$
I get a feeling I am missing something fundamental - but RTFM did not
help much... Could anyone please nudge me in the correct direction ?
Thanks a lot!
--a
___
Cocci mailing list
Cocci@systeme.lip6.fr
https://systeme.lip6.fr/mailman/listinfo/cocci
[Cocci] [PATCH] scripts: coccinelle: allow list_entry_is_head() to use pos
Currently use_after_iter.cocci generates false positives for code of the
following form:
~~~
list_for_each_entry(d, &ddata->irq_list, node) {
if (irq == d->irq)
break;
}
if (list_entry_is_head(d, &ddata->irq_list, node))
return IRQ_NONE;
~~~
[This specific example comes from drivers/power/supply/cpcap-battery.c]
Most list macros use list_entry_is_head() as loop exit condition meaning it
is not unsafe to reuse pos (a.k.a. d) in the code above.
Let's avoid reporting these cases.
Signed-off-by: Daniel Thompson
---
Notes:
I'm pretty much a complete beginner w.r.t. SmPL. This is written
entirely by finding previous fixes and emulating them!
However I did test it by running the checker across the current kernel
tree. The changes reduced the error count by four... which was small
enough for me to eyeball each one and check they match the pattern I
was targetting.
scripts/coccinelle/iterators/use_after_iter.cocci | 2 ++
1 file changed, 2 insertions(+)
diff --git a/scripts/coccinelle/iterators/use_after_iter.cocci
b/scripts/coccinelle/iterators/use_after_iter.cocci
index 9be48b520879..676edd562eef 100644
--- a/scripts/coccinelle/iterators/use_after_iter.cocci
+++ b/scripts/coccinelle/iterators/use_after_iter.cocci
@@ -123,6 +123,8 @@ hlist_for_each_entry_safe(c,...) S
|
list_remove_head(x,c,...)
|
+list_entry_is_head(c,...)
+|
sizeof(<+...c...+>)
|
&c->member
base-commit: 2734d6c1b1a089fb593ef6a23d4b70903526fe0c
--
2.30.2
___
Cocci mailing list
Cocci@systeme.lip6.fr
https://systeme.lip6.fr/mailman/listinfo/cocci
Re: [Cocci] [PATCH] scripts: coccinelle: allow list_entry_is_head() to use pos
On Fri, 30 Jul 2021, Daniel Thompson wrote:
> Currently use_after_iter.cocci generates false positives for code of the
> following form:
> ~~~
> list_for_each_entry(d, &ddata->irq_list, node) {
> if (irq == d->irq)
> break;
> }
>
> if (list_entry_is_head(d, &ddata->irq_list, node))
> return IRQ_NONE;
> ~~~
> [This specific example comes from drivers/power/supply/cpcap-battery.c]
>
> Most list macros use list_entry_is_head() as loop exit condition meaning it
> is not unsafe to reuse pos (a.k.a. d) in the code above.
>
> Let's avoid reporting these cases.
>
> Signed-off-by: Daniel Thompson
> ---
>
> Notes:
> I'm pretty much a complete beginner w.r.t. SmPL. This is written
> entirely by finding previous fixes and emulating them!
>
> However I did test it by running the checker across the current kernel
> tree. The changes reduced the error count by four... which was small
> enough for me to eyeball each one and check they match the pattern I
> was targetting.
This looks fine. Thanks for the proposal.
julia
>
> scripts/coccinelle/iterators/use_after_iter.cocci | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/scripts/coccinelle/iterators/use_after_iter.cocci
> b/scripts/coccinelle/iterators/use_after_iter.cocci
> index 9be48b520879..676edd562eef 100644
> --- a/scripts/coccinelle/iterators/use_after_iter.cocci
> +++ b/scripts/coccinelle/iterators/use_after_iter.cocci
> @@ -123,6 +123,8 @@ hlist_for_each_entry_safe(c,...) S
> |
> list_remove_head(x,c,...)
> |
> +list_entry_is_head(c,...)
> +|
> sizeof(<+...c...+>)
> |
> &c->member
>
> base-commit: 2734d6c1b1a089fb593ef6a23d4b70903526fe0c
> --
> 2.30.2
>
>
___
Cocci mailing list
Cocci@systeme.lip6.fr
https://systeme.lip6.fr/mailman/listinfo/cocci
