[slang-users] Memory leak found (w/solution) in: posix_read() in slposio.c module

["Gonzalez, Jorge" <jgonzalez@xxxxxxxxxxxxxxxxx>]

Hi,

 

I was doing some serial communication programming with slang 1.4.5 on
QNX4 and found and interesting behavior of the POSIX compatible read
function.

Every time I used that function to get the contents of the serial input
buffer, I noticed that my application leaked memory in 8K chunks. I had
a look at the implementation of the posix_read() function included in
the slposio.c module and found that a SLbstring_free() call was missing.
So when I put that in and recompiled the library the mem leak was gone.

 

I wonder if somebody else has noticed/fixed this before and I apologize
if that is the case, I might just be late with the news.

Otherwise, the fix goes as follows. Please look for the /*** MEM LEAK
FIX ***/ comments.

 

Thanks,

Jorge Gonzalez

 

P.S. I also checked the 1.4.9 version and it does the same thing. :-)

 

 

 

/* Usage: nn = read (f, &buf, n); */

static void posix_read (SLFile_FD_Type *f, SLang_Ref_Type *ref, unsigned
int *nbytes)

{

   unsigned int len;

   char *b;

   SLang_BString_Type *bstr;

 

   b = NULL;

 

   len = *nbytes;

   if ((-1 == check_fd (f->fd))

       || (NULL == (b = SLmalloc (len + 1))))

     goto return_error;

 

   if (-1 == f->read (f->fd, b, &len))

     {

            _SLerrno_errno = errno;

            goto return_error;

     }

 

   if (len != *nbytes)

     {

            char *b1 = SLrealloc (b, len + 1);

            if (b1 == NULL)

              goto return_error;

            b = b1;

     }

 

   bstr = SLbstring_create_malloced ((unsigned char *) b, len, 0);

   if (bstr != NULL)

     {

            if ((-1 != SLang_assign_to_ref (ref, SLANG_BSTRING_TYPE,
(VOID_STAR)&bstr))

                && (-1 != SLang_push_uinteger (len)))

              {                                             /*** MEM
LEAK FIX ***/

              SLbstring_free (bstr);                /*** MEM LEAK FIX
***/

              return;

              }                                             /*** MEM
LEAK FIX ***/

 

            SLbstring_free (bstr);

            b = NULL;

            /* drop */

     }

 

   return_error:

   if (b != NULL) SLfree ((char *)b);

   (void) SLang_assign_to_ref (ref, SLANG_NULL_TYPE, NULL);

   (void) SLang_push_integer (-1);

}

 

 

_______________________________________________
To unsubscribe, visit http://jedsoft.org/slang/mailinglists.html