read string from server array error!

[fang zhengshu]

2009/7/8 fang zhengshu <fangzhsh07 at gmail.com>

>
>
> 2009/7/6 fang zhengshu <fangzhsh07 at gmail.com>
>
>> hi all,
>> when I write a function in the IDL file, there is a problem:want to write
>> a different-length string to a array and then read  parts of the array to
>> another string like:
>>
>> interface test{
>>         int write([string]char* str, int len);
>>         int read([out,prealloc_client, size_is(size), prealloc_server]char
>> str[], int size);
>>        };
>>
> I modify the idl file as the following:
          int write([in,string]char *str, int len)
          int read([out, prealloc_client]char *str, int len)
there no error when compile it,but

>
>> I have defined a fixed size array in the server like array[256].
>> In the write() function I write a different length string to the array,
>> then I want to read parts or all of the array in the read() function, the
>> process will be like the following:
>>
>> string[len]                               str[size]
>>         |                                        ^
>>         |                                         |
>>         --------->array[256] -----------|
>>
>>
>> but when I put the function above and compile it, there are some error
>> happen. I have change the size_is() with length_is() or max_is(), but there
>> still error when I compile it. I know if I define a fix array str[256] the
>> code can be work, but I just want to use a unfixed length array to get the
>> string.
>> could someone please give me some advice?if I describe the problem
>> clearly, please let me know.
>>
>> thank you!
>>
>> I don't know whether  I describe what I want to do clearly,so I put the
> simple code below:
>
> read-client
>                                             write-client
> #define STR_TO 30
>                                               #define STR_FROM 30
> ...
>                                                                   ...
> char str_to[SRR_TO];
>                                            char str_from[STR_FROM];
> ...
>                                                                   ...
> read(str_to, STR_TO);
>                                           write(str_from, STR_FROM);
> ...
>                       ...
>
>                                                       server
>                                                      #define SIZE 256
>                                                      ...
>                                                     char string[SIZE];
>                                                     ...
>                                                     int write(char
> *str_from, int str_from)
>                                                    {
>                  //write str_from size chars of str_from array to the
> string array which is in server
>                                                    }
>                                                    int read(char *str_to,
> int str_to)
>                                                   {
>                 //read str_to size chars from the string array which is in
> server to str_to
>                                                    }
>
> Then I define write functions as the above in a .idl file,but when I
> compile it,there will be the following error:
> terminate called after throwing an instance of 'std::out_of_range'
>   what():  CBEMsgBuffer::IsEarlier
> make[1]: *** [test-server.c] Aborted
> make[1]: *** [test-server.c] Deleting file `test-sys.h'
> make[1]: *** [test-server.c] Deleting file `test-client.h'
> make[1]: *** [test-server.c] Deleting file `test-client.c'
> make: *** [/home/l4/tudos/build/pkg/
> fifo/idl/OBJ-x86-l4v2] Error 2
>
> must we use the format as the dice manual below?:
> int read([out, prealloc_client, size_is(len)] char **str, [out,in]int *len)
>  and when I modify the function as
> int read([out, prealloc_client, prealloc_server, size_is(len)] char *str,
> [out,in]int *len)
> there is no error when compile it,but there will be another error called
> :fpage
> could you give me some advice for the read function?
> thank you.
> --
> fang,
>
when I run the test in qemu, the error come out:
   fifo    | L4RM: [PF] read at 0x00002000, ip 01800aa1, src B.02
   fifo    | [B.0] l4rm/lib/src/pagefault.c:81:__unknown_pf():
   fifo    |  unhandled page fault

the execute code of fifo binary is :
...
/home/l4/tudos/build/pkg/fifo/idl/OBJ-x86-l4v2/fifo-server.c:259
            l4_msgdope_t _dice_size_dope;
            l4_msgdope_t _dice_send_dope;
            l4_umword_t _word[2];
        } _word;
    } fifo_fifo_read_msg_buffer_t;
    l4_umword_t _dice_str_size = (str) ? (_dice_strlen(str)+1) : 0;
 1800a8b:    85 db                    test   %ebx,%ebx
 1800a8d:    0f 84 f9 00 00 00        je     1800b8c <fifo_dispatch+0x21c>
 1800a93:    80 3b 00                 cmpb   $0x0,(%ebx)
 1800a96:    0f 84 11 01 00 00        je     1800bad <fifo_dispatch+0x23d>
 1800a9c:    31 c0                    xor    %eax,%eax
 1800a9e:    66 90                    xchg   %ax,%ax
 1800aa0:    40                       inc    %eax
 1800aa1:    80 3c 18 00              cmpb   $0x0,(%eax,%ebx,1)
 1800aa5:    75 f9                    jne    1800aa0 <fifo_dispatch+0x130>
 1800aa7:    8d 58 01                 lea    0x1(%eax),%ebx
...

the fifo-server.c:259 code is:

inline
void
fifo_read_marshal (CORBA_Object _dice_corba_obj,
                   int _dice_return /* out */,
                   l4_msgtag_t *_dice_tag,
                   char* str /* out */,
                   fifo_msg_buffer_t *_dice_msg_buffer,
                   CORBA_Server_Environment *_dice_corba_env)
{

 ...
    l4_umword_t _dice_str_size = (str) ? (_dice_strlen(str)+1) : 0;
 ...


so anyone can give me some advice?

thank you!
-- 
fang,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://os.inf.tu-dresden.de/pipermail/l4-hackers/attachments/20090710/93e96650/attachment.html>