[bugs][ bogofilter-Bugs-653523 ] xcalloc 0 elements fail

[<no...@so...>]

Bugs item #653523, was opened at 2002-12-14 01:00
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Category: None
Group: None
Status: Closed
>Resolution: Out of Date
Priority: 5
Submitted By: Dan Nguyen (dnn)
Assigned to: Nobody/Anonymous (nobody)
Summary: xcalloc 0 elements fail

Initial Comment:
xcalloc wraps around a call to calloc, and then checks 
the pointer returned.  However if calloc is called with 
either elements or element size set to 0. The return 
value is implementation defined.  

http://www.opengroup.org/onlinepubs/007904975/functio
ns/calloc.html

"If either nelem or elsize is 0, then either a null pointer 
or a unique pointer value that can be successfully 
passed to free() shall be returned. "

On some platforms, the tests will fail because it thinks 
the calloc of 0 elements returned NULL, which is not an 
error condition.  

The only portable way to detect the error condition is to 
check the errno value to see if it ENOMEM.

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>Comment By: Matthias Andree (m-a)
Date: 2002-12-14 03:26

Message:
Logged In: YES 
user_id=2788

Yes, 0.9.1.2 still had the non-portable xcalloc code that falsely aborted the program when xcalloc(0,0) returned NULL.

Please, before reporting the next problem if you have a detailed analysis, look into the CVS repository (you can browse it online) if the latest version fixes the problem. If you cannot spare the time or don't know the exact location of the defect, then please remember to include the bogofilter version number in your report. 

JFTR: bogofilter -V will print it.

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Comment By: Dan Nguyen (dnn)
Date: 2002-12-14 03:10

Message:
Logged In: YES 
user_id=129888

This is 0.9.1.2.  This should fix the problem thanks.

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Comment By: Matthias Andree (m-a)
Date: 2002-12-14 03:03

Message:
Logged In: YES 
user_id=2788

What version of bogofilter do you refer to?

The CVS version (2002-12-06) looks fine to me, even though it doesn't check ENOMEM, it won't fall prey to NULL == calloc(0,x) or NULL == calloc(x,0). It's ugly, but that's the way autoconf recommends.

     6  void
     7  *xcalloc(size_t nmemb, size_t size){
     8     void *x;
     9     x = calloc(nmemb, size);
    10     if (x == NULL && (nmemb == 0 || size == 0))
    11         x = calloc(1, 1);
    12     if (x == NULL) {
    13         xmem_error("xcalloc");
    14     }
    15     return x;
    16  }

Also available from: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/bogofilter/bogofilter/xcalloc.c?rev=1.2&content-type=text/vnd.viewcvs-markup

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=499997&aid=653523&group_id=62265