failed malloc()?

Christopher Faylor cgf@redhat.com
Sat Nov 25 17:36:00 GMT 2000


On Sat, Nov 25, 2000 at 05:24:31PM -0800, Matt wrote:
>On Sat, 25 Nov 2000, Christopher Faylor wrote:
>
>> On Sat, Nov 25, 2000 at 03:41:59PM -0800, Matt wrote:
>> >I've started reviewing some of the winsup code and had a question as to
>> >how to most properly correct unchecked pointers. That is, I know to add a
>> >statement to check the freshly created/passed pointer, but not what to do
>> >in the instance that pointer is NULL. 
>> >
>> >Some places in the cygwin code do a system_printf() which is what I will
>> >assume is desired, but wanted to check to make sure what the
>> >standard/preferred way of handling such things is (if there is one).
>> >
>> >Here one of the sections of code I am looking at (cygcheck.c:91,92):
>> >  paths[num_paths] = (char *) malloc (maxlen + 1);
>> >  memcpy (paths[num_paths], s, maxlen);
>> 
>> Um.  That's not cygwin, that's cygcheck.  Proper programming practice would
>> be to check every single malloc and issue an error if there is a problem.
>> 
>> You can't use system_printf in this case since it isn't cygwin that you're
>> looking at.
>> 
>> It is usually a sign of some severe memory corruption if a program like
>> cygcheck isn't able to allocate its own buffers so I am not too worried
>> that there is no protection in this code.
>
>I wanted to start with something simple first, and once I got
>comfortable/proficient, moving onto cygwin itself. 
>
>What would be the preferred method to output these error messages?
>
>I am using the format "file: function: message". For example,
>"cygcheck.cc: get_word(): Readfile returned error (GetLastError)".

Look for other error messages and copy that.  Finding usage of 'stderr'
would be one way to start.

cgf


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