Re: [RFC] Bug zapper? :)

[John Richard Moser]

Denis Vlasenko wrote:
> On Monday 09 August 2004 23:07, John Richard Moser wrote:

[...]

> The flaw is that you think that kernel folks don't review their code.
> However, if you see some bad code, by all means - send a patch.

Oh, no; as I said, even heavily quality assurance audited code has maybe 
5 bugs per kloc.  Where do the mremap() and munmap() bugs come from? 
Obviously you guys don't get everything.

> Asking others to do large amount of work is not very popular on this list.
> Do something yourself first.

Just do it in passing; you don't have to put a sudden hard effort to do 
these things in.  It'd be nice, but a major undertaking.

What I'm suggesting isn't much though, is it really?  Consider the 
functions function (normal code, not necessarily kernel):

void get_food(char **a) {
*a = malloc(strlen(global_food) + 1);
strcpy(*a, global_food);
}

/*Set our food*/
int set_food(char *food) {
if (!food)
return -1; /*error*/
free(global_food); /*if NULL, nothing happens*/
global_food = malloc(strlen(food) + 1);
strcpy(global_food, food);
return 0;
}

You'll have to forgive the lack of formatting; thunderbird is mean about 
this :/

Anyhow, as you can see, these are quite simple.  Function names are 
self-eplanitory, as is the process.  Assumedly, these are fine.

Now, we could try another approach at this, below.

/* get_food(char **a)
* Gets the current food.
*
* INPUT:
*  - char **a
*    Pointer to a pointer for the outputted food.
* OUTPUT:
*  - Return
*    none.
*  - *a
*    Set to a copy of the current food.
* PROCESS:
*  - Set '*a' to a newly allocated block of memory containing a copy
*    of the current food (global_food)
* STATE CHANGE:
*  none.
*/
void get_food(char **a) {
*a = malloc(strlen(global_food) + 1);
strcpy(*a, global_food);
}

/* set_food(char *food)
* Sets the current food.
*
* INPUT:
*  - char *food
*    Pointer to an ASCIIZ string containing the new food
* OUTPUT:
*  - Return
*    -1 on error
*    0 on success
* PROCESS:
*  - If (food is NULL)
*    - return error (-1)
*  - If (food is not NULL)
*    - Free current food (global_food)
*    - Set current food (global_food) to a newly allocated block
*      of memory containing a copy of 'food'
* STATE CHANGE:
*  - current food (global_food) is set to 'food'
*  - Memory holding previous food is freed
*/
int set_food(char *food) {
if (!food)
return -1; /*error*/
free(global_food); /*if NULL, nothing happens*/
global_food = malloc(strlen(food) + 1);
strcpy(global_food, food);
return 0;
}


These comment blocks are *MUCH* more verbose.  They describe the process 
loosely, but do give enough information to allow understanding without 
questions.

The large amount of extra commentary is worth it, IMHO.
> --
> vda

--
All content of all messages exchanged herein are left in the
Public Domain, unless otherwise explicitly stated.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/