Re: gmake and ccache conspiring together in creating gremlins

[David Boyce]

> The program could read this -1 to (for example) uint16_t and interpret as 65535 and fail to notice the parent is not giving any fd.

File descriptors have been of int type since Unix was designed (at least) and -1 is documented as the invalid descriptor. E.g. the open() system call and every other system call returning an fd returns -1 on error and always has. The idea that any program would read something explicitly documented as a file descriptor into an unsigned type seems effectively inconceivable.

David

On Tue, Feb 9, 2021 at 7:36 AM Dmitry Goncharov via Bug reports and discussion for GNU make <bug-make@gnu.org> wrote:

On Tue, Feb 9, 2021 at 5:31 AM Edward Welbourne <edward.welbourne@qt.io> wrote:

> Rather than removing the jobserver-auth data, you could amend the
> MAKEFLAGS to includ jobserver-auth data with plainly invalid fds,

i like jobserver-auth data with plainly invalid fds, because it lets
older binaries fail on parsing jobserver-auth
and print some (hopefully useful) error message.
E.g. make itself would print
"internal error: invalid --jobserver-auth string"


> e.g. -1, as the two fds

The program could read this -1 to (for example) uint16_t and interpret
as 65535 and fail to notice the parent is not giving any fd.
i'd rather provide no fd at all. E.g.
--jobserver-auth=

regards, Dmitry


>
>         Eddy.
>