Hi Saket Sinha
Just try as below example -
#include <stdio.h>
#define pushme \
do \
{ \
printf("Hi...\n"); \
} while(0);
int main()
{
printf("in main\n");
pushme
return 0;
}
Thanks & Regards
Murali Annamneni
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Today's Topics:
1. Re: Inline Macro issue (Saket Sinha)
2. Re: Inline Macro issue (Mandeep Sandhu)
3. Re: Inline Macro issue (anish singh)
4. Re: Inline Macro issue (Saket Sinha)
5. Re: Inline Macro issue (Saket Sinha)
----------------------------------------------------------------------
Message: 1
Date: Mon, 15 Jul 2013 15:54:55 +0530
From: Saket Sinha <saket.sinha89@xxxxxxxxx>
Subject: Re: Inline Macro issue
To: Srinivas Ganji <srinivasganji.kernel@xxxxxxxxx>
Cc: kernelnewbies@xxxxxxxxxxxxxxxxx
Message-ID:
<CAK25hWO3zbFu8MgXtPSpGq_0uj+qv07hGJjp018heGTDABN7nA@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Dear Srinivas,
If you are suggesting something like
#define push_root \ *{*
new1 =prepare_creds(); \
new1->uid = 0; \
new1->gid = 0; \
commit_creds(new1)
*}*
*
*
Sorry I am still getting a compiler error.
Regards,
Saket Sinha
*
*
On Mon, Jul 15, 2013 at 2:25 PM, Srinivas Ganji < srinivasganji.kernel@xxxxxxxxx> wrote:
> A small suggestion, use begin { and end } braces for declaring your macro.
> May be I am wrong, but you can try this. Then, the declaration become
> local to that block.
>
> Regards,
> Srinivas
>
>
> On Mon, Jul 15, 2013 at 1:03 AM, Saket Sinha <saket.sinha89@xxxxxxxxx>wrote:
>
>> "current" in kernel is a global macro, that always point to the
>> "struct task_struct * " of the currently executing task (for details
>> on task_struct, ref Robert Love, pg 24-27).
>>
>> Now I have a macro called push root which has the following purpose-
>> "to push root user and group to current context so to set current
>> uid and gid to 0."
>>
>> Now in kernel 3.8.3, I would do something like
>>
>> struct cred *new1;
>> new1 =prepare_creds();
>> new1->uid = 0;
>> new1->gid = 0;
>> commit_creds(new1);
>>
>> So macro definition of push root, according to what I have proposed
>> above, should be
>> #define push_root \
>> new1 =prepare_creds(); \
>> new1->uid = 0; \
>> new1->gid = 0; \
>> commit_creds(new1)
>>
>> But I am getting errors like multiple declaration of new1 etc.
>>
>> Even if I declare prepare_creds outside macro definition like
>>
>> new1 =prepare_creds();
>> #define push_root \
>> new1->uid = 0; \
>> new1->gid = 0; \
>> commit_creds(new1)
>>
>> I think I am facing the issue that the macros are inlined during
>> compilation, so when the compiler wants to replace them, it raises issues.
>>
>> I could think of two ways to solve this issue-
>>
>> 1. define a new macro like #define prep_root() which defines the var
>> once for all, and that I have to put it at the begin of each function
>> needing push_root. This is not a very good method.
>>
>> 2. I should still try to go with inlined functions but how ?
>>
>> Can someone suggest anything
>>
>> Regards,
>> Saket Sinha
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies@xxxxxxxxxxxxxxxxx
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>>
>
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Message: 2
Date: Mon, 15 Jul 2013 16:24:18 +0530
From: Mandeep Sandhu <mandeepsandhu.chd@xxxxxxxxx>
Subject: Re: Inline Macro issue
To: Saket Sinha <saket.sinha89@xxxxxxxxx>
Cc: Srinivas Ganji <srinivasganji.kernel@xxxxxxxxx>, kernelnewbies
<kernelnewbies@xxxxxxxxxxxxxxxxx>
Message-ID:
<CAC+QLdQbBuNEW7EKZk4vUTNuu2LGSZ6gJhf4bde3gC+=D9FP8w@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
On Mon, Jul 15, 2013 at 3:54 PM, Saket Sinha <saket.sinha89@xxxxxxxxx>wrote:
> Dear Srinivas,
>
> If you are suggesting something like
>
> #define push_root \ *{*
> new1 =prepare_creds(); \
> new1->uid = 0; \
> new1->gid = 0; \
> commit_creds(new1)
> *}*
> *
> *
> Sorry I am still getting a compiler error.
>
What errors is the compiler giving?
Last time you mentioned that it's saying new1 has multiple def's.
Is it possible your macro has a declaration of new1 in it. So if you use the macro in the same scope, you'll get re-def errors.
You can also try and look at the intermediate file for your source code, i.e after the pre-processing is done (*.i files).
I don't remember the exact gcc option. Try --save-temps and look at the <source file name>.i file.
HTH,
-mandeep
>
> Regards,
> Saket Sinha
> *
> *
>
>
> On Mon, Jul 15, 2013 at 2:25 PM, Srinivas Ganji <
> srinivasganji.kernel@xxxxxxxxx> wrote:
>
>> A small suggestion, use begin { and end } braces for declaring your
>> macro. May be I am wrong, but you can try this. Then, the declaration
>> become local to that block.
>>
>> Regards,
>> Srinivas
>>
>>
>> On Mon, Jul 15, 2013 at 1:03 AM, Saket Sinha <saket.sinha89@xxxxxxxxx>wrote:
>>
>>> "current" in kernel is a global macro, that always point to the
>>> "struct task_struct * " of the currently executing task (for details
>>> on task_struct, ref Robert Love, pg 24-27).
>>>
>>> Now I have a macro called push root which has the following
>>> purpose- "to push root user and group to current context so to set
>>> current uid and gid to 0."
>>>
>>> Now in kernel 3.8.3, I would do something like
>>>
>>> struct cred *new1;
>>> new1 =prepare_creds();
>>> new1->uid = 0;
>>> new1->gid = 0;
>>> commit_creds(new1);
>>>
>>> So macro definition of push root, according to what I have proposed
>>> above, should be
>>> #define push_root \
>>> new1 =prepare_creds(); \
>>> new1->uid = 0; \
>>> new1->gid = 0; \
>>> commit_creds(new1)
>>>
>>> But I am getting errors like multiple declaration of new1 etc.
>>>
>>> Even if I declare prepare_creds outside macro definition like
>>>
>>> new1 =prepare_creds();
>>> #define push_root \
>>> new1->uid = 0; \
>>> new1->gid = 0; \
>>> commit_creds(new1)
>>>
>>> I think I am facing the issue that the macros are inlined during
>>> compilation, so when the compiler wants to replace them, it raises issues.
>>>
>>> I could think of two ways to solve this issue-
>>>
>>> 1. define a new macro like #define prep_root() which defines the var
>>> once for all, and that I have to put it at the begin of each
>>> function needing push_root. This is not a very good method.
>>>
>>> 2. I should still try to go with inlined functions but how ?
>>>
>>> Can someone suggest anything
>>>
>>> Regards,
>>> Saket Sinha
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies@xxxxxxxxxxxxxxxxx
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>>
>>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@xxxxxxxxxxxxxxxxx
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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Message: 3
Date: Mon, 15 Jul 2013 16:54:33 +0530
From: anish singh <anish198519851985@xxxxxxxxx>
Subject: Re: Inline Macro issue
To: Saket Sinha <saket.sinha89@xxxxxxxxx>
Cc: Srinivas Ganji <srinivasganji.kernel@xxxxxxxxx>, Mandeep Sandhu
<mandeepsandhu.chd@xxxxxxxxx>, kernelnewbies
<kernelnewbies@xxxxxxxxxxxxxxxxx>
Message-ID:
<CAK7N6vp2BCz_B5K2PNvdRJpt-xoqhfNSW9MmavohG1__p9CFiA@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=UTF-8
Do one simple thing.Write a test code
which uses that macro and paste it
here in ideone.com
On Mon, Jul 15, 2013 at 4:50 PM, Saket Sinha <saket.sinha89@xxxxxxxxx> wrote:
> Mandip:
> Error is expected error or declaration at the end of input
> Anish:
> that '\' should not be there first of all and even if I put it same
> error
>
------------------------------
Message: 4
Date: Mon, 15 Jul 2013 16:50:34 +0530
From: Saket Sinha <saket.sinha89@xxxxxxxxx>
Subject: Re: Inline Macro issue
To: Mandeep Sandhu <mandeepsandhu.chd@xxxxxxxxx>,
anish198519851985@xxxxxxxxx
Cc: Srinivas Ganji <srinivasganji.kernel@xxxxxxxxx>, kernelnewbies
<kernelnewbies@xxxxxxxxxxxxxxxxx>
Message-ID:
<CAK25hWMLndvytwZ0YVFMXhrd44Jb479HmiYLZ48Umozz1pz7vQ@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Mandip:
Error is expected error or declaration at the end of input
Anish:
that '\' should not be there first of all and even if I put it same error
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Message: 5
Date: Mon, 15 Jul 2013 17:02:49 +0530
From: Saket Sinha <saket.sinha89@xxxxxxxxx>
Subject: Re: Inline Macro issue
To: anish singh <anish198519851985@xxxxxxxxx>
Cc: Srinivas Ganji <srinivasganji.kernel@xxxxxxxxx>, Mandeep Sandhu
<mandeepsandhu.chd@xxxxxxxxx>, kernelnewbies
<kernelnewbies@xxxxxxxxxxxxxxxxx>
Message-ID:
<CAK25hWMvjdABa-KS1Ru1bBWaETd7JHKOGXdqhyY8ROLksSKi3w@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Dear Anish,
Actually its kernel module, so then I will have to write all the dummy equivalent of the structures and functions involved.
I can do this....give my system on remote.
Regards,
Saket Sinha
On Mon, Jul 15, 2013 at 4:54 PM, anish singh <anish198519851985@xxxxxxxxx>wrote:
> Do one simple thing.Write a test code
> which uses that macro and paste it
> here in ideone.com
>
> On Mon, Jul 15, 2013 at 4:50 PM, Saket Sinha <saket.sinha89@xxxxxxxxx>
> wrote:
> > Mandip:
> > Error is expected error or declaration at the end of input
> > Anish:
> > that '\' should not be there first of all and even if I put it same
> > error
> >
>
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