C.Mohanasundaram wrote:
>> In my userland code, I change new system call
>> our_sys_open("mytest", O_RDONLY, 0444); into
>> #include <unistd.h>
>> ...
>> _syscall3(errno, "our_sys_open", name, "mytest", filename, O_RDONLY,
>> flags, 0444);
>> ...
>
>
> this is how the macro will look like
> _syscall3(type,name,type1,arg1,type2,arg2,type3,arg3);
>
> type - return type(int,long etc)
> name - function name (in ur case our_sys_open not "our_sys_open")
> type 1 - type of 1st argument (int, struct something *,etc)
> arg1 - first argument of ur system call.(in ur case mytest not "mytest")
> type 2 - same like above
> arg2 - "
> type 3 - "
> arg 3 - "
>
> refer asm/unistd.h for the macro.
>
> the statement should like
> _syscall3(int,our_sys_open,<data type of mytest>,mytest,<data
> type>,O_RDONLY,<data type>,0444);
>
> dont use any double quotes like "our_sys_call" that is our_sys_call
> and "mytest" should be simply mytest
>
>> the compilation still gives me error: undefined reference to `_syscall3'
>>
>> I guess there is something I am still missing,
>> -Hong
>
> dont forget to include asm/unistd.h
>
> if u still have trouble i will send u some code.because putting the whole
> code here will waste everyone's disk space.i have done similar kinda work.
>
> regards,
> mohan.
>
mohan,
I use kernel 2.4.2. At this stage, my code:
#include <linux/unistd.h>
......
/* generate syscall stub */
_syscall4(int, foo, struct result *, &result,
const char *, filename, int, flags, int, mode);
/*line143 */
/* invoke system call */
m_errno = foo(&result, "mytest", O_RDONLY, 0444);
......
gives me error: observer.c:143: `__res' undeclared (first use in this
function)
as I compile my above userland code as follow:
#gcc -c -Wall -O2 observer.c
my module code is:
asmlinkage int sys_foo(struct result *res, const char *filename, int
flags, int mode)
{
...
}
I would like to look at your code. You may send it to me directly at
honghsu@bellatlantic.net
Many thanks,
-Hong
-
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