On Fri, Aug 26, 2005 at 12:44:37PM +0200, Han Boetes wrote:
> Hi,
>
> I was looking for an example of a cleanup with free() while
> running into a fatal error which causes a direct errx() etc.
>

Don't cleanup on error pathes that exit the program. Exit does that for
you and doing free() in case of errors may help heap overflows.

> Not that I found it, but I found in df a malloc() without a
> free(). Now I wonder how important it is to free() for a oneshot
> program like df.
>

It may make sense for some oneshot programs to clean up allocations during
runtime to keep the memory footprint low. There is no need to cleanup
before any kind of exit (or exec).

> If it is important I'd like to suggest this patch:
>
> Index: df.c
> ================================================== =================
> RCS file: /cvs/src/bin/df/df.c,v
> retrieving revision 1.43
> diff -u -p -r1.43 df.c
> --- df.c 20 Feb 2005 01:34:56 -0000 1.43
> +++ df.c 26 Aug 2005 10:26:43 -0000
> @@ -118,8 +118,10 @@ main(int argc, char *argv[])
> Pflag = 1;
> break;
> case 't':
> - if (typelist != NULL)
> + if (typelist != NULL) {
> + free(typelist);
> errx(1, "only one -t option may be specified.");
> + }
> maketypelist(optarg);
> break;
> default:
> @@ -188,6 +190,9 @@ main(int argc, char *argv[])
> else
> bsdprint(mntbuf, mntsize, maxwidth);
> }
> +
> + if (typelist != NULL)
> + free(typelist);
>
> exit(mntsize ? 0 : 1);
> }
>
>

In both cases some sort of exit is called and so the cleanup is done
automaticaly.

--
:wq Claudio