Re: [musl] Re: sysconf(_SC_NPROCESSORS_CONF) broken.

[enh <enh@google.com>]

On Fri, Jul 29, 2022 at 11:53 AM NRK <nrk@disroot.org> wrote:
>
> On Fri, Jul 29, 2022 at 11:42:19AM -0700, enh wrote:
> > done: https://android-review.googlesource.com/c/platform/bionic/+/2168844
>
>         if (getline(&line, &allocated_size, fp) != -1) {
>           cpu_count = GetCpuCountFromString(line);
>           free(line);
>         }
>
> Shouldn't the buffer be `free`-ed regardless or weather getline fails or
> not? The getline(3) manpage suggests so:

yeah, i almost changed that in passing (because i worried that someone
would copy & paste for a loop, where you don't want to free() on every
iteration) but assumed (incorrectly!) that earlier me had checked.

fixed now, thanks:
https://android-review.googlesource.com/c/platform/bionic/+/2170542

> > If *lineptr is set to NULL before the call, then getline() will
> > allocate a buffer for storing the line. This buffer should be freed by
> > the user program even if getline() failed.

it looks like it's not entirely theoretical either --- a quick look at
bionic's [OpenBSD] getdelim() implementation shows that it can return
failure on the first call but leaving buf non-null (you'd need the
first allocation to succeed, and need a second allocation that fails;
which -- along with the fact -- is probably why i don't remember ever
seeing this in practice).

i'll send a patch to man7.org to mention this in the ERRORS section,
because i didn't see it up top when i looked before getting to the
part of your mail with a ctrl-f'able quote :-)

> - NRK