[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Re: [PATCH 1/2] qemu-io: retry fgets() when errno is EI
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] Re: [PATCH 1/2] qemu-io: retry fgets() when errno is EINTRg |
Date: |
Thu, 17 Jun 2010 18:18:18 +0100 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Kevin Wolf wrote:
> Am 16.06.2010 18:52, schrieb MORITA Kazutaka:
> > At Wed, 16 Jun 2010 13:04:47 +0200,
> > Kevin Wolf wrote:
> >>
> >> Am 15.06.2010 19:53, schrieb MORITA Kazutaka:
> >>> posix-aio-compat sends a signal in aio operations, so we should
> >>> consider that fgets() could be interrupted here.
> >>>
> >>> Signed-off-by: MORITA Kazutaka <address@hidden>
> >>> ---
> >>> cmd.c | 3 +++
> >>> 1 files changed, 3 insertions(+), 0 deletions(-)
> >>>
> >>> diff --git a/cmd.c b/cmd.c
> >>> index 2336334..460df92 100644
> >>> --- a/cmd.c
> >>> +++ b/cmd.c
> >>> @@ -272,7 +272,10 @@ fetchline(void)
> >>> return NULL;
> >>> printf("%s", get_prompt());
> >>> fflush(stdout);
> >>> +again:
> >>> if (!fgets(line, MAXREADLINESZ, stdin)) {
> >>> + if (errno == EINTR)
> >>> + goto again;
> >>> free(line);
> >>> return NULL;
> >>> }
> >>
> >> This looks like a loop replaced by goto (and braces are missing). What
> >> about this instead?
> >>
> >> do {
> >> ret = fgets(...)
> >> } while (ret == NULL && errno == EINTR)
> >>
> >> if (ret == NULL) {
> >> fail
> >> }
> >>
> >
> > I agree.
> >
> > However, it seems that my second patch have already solved the
> > problem. We register this readline routines as an aio handler now, so
> > fgets() does not block and cannot return with EINTR.
> >
> > This patch looks no longer needed, sorry.
>
> Good point. Thanks for having a look.
Anyway, are you sure stdio functions can be interrupted with EINTR?
Linus reminds us that some stdio functions have to retry internally
anyway:
http://comments.gmane.org/gmane.comp.version-control.git/18285
-- Jamie