From: Pip Cet <pipcet@gmail.com>
To: 6074@debbugs.gnu.org
Subject: bug#6074: accept-process-output on listening sockets cause non-interruptible infloop
Date: Mon, 22 Jul 2019 03:52:33 +0000 [thread overview]
Message-ID: <CAOqdjBfKkdExF1366V_W-UhDXrB27EQyJ1-PF1HeiFmErY=LrQ@mail.gmail.com> (raw)
In-Reply-To: <m2y6g3mfom.fsf@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 946 bytes --]
> With this code Emacs seems to be stuck in an endless loop and is not
> incorruptible with C-g:
> (let ((proc (make-network-process :name "foo" :server t :noquery t
> :family 'local :service "/tmp/foo.socket")))
> (accept-process-output proc))
On Linux, the problem appears to be that we don't abort this infloop
in process.c if a read () returns EINVAL:
while (true)
{
int nread = read_process_output (proc, wait_proc->infd);
if (nread < 0)
{
if (errno == EIO || would_block (errno))
break;
}
else
{
if (got_some_output < nread)
got_some_output = nread;
if (nread == 0)
break;
read_some_bytes = true;
}
}
That seems problematic to me, since we might get non-EIO errors for
other reasons. I'm attaching a patch that appears to fix the issue.
[-- Attachment #2: 0001-Don-t-retry-reading-after-receiving-EINVAL-bug-6074.patch --]
[-- Type: text/x-patch, Size: 849 bytes --]
From ad294bb1e7ff7012dca3345a8ca2046e0f9dc8fb Mon Sep 17 00:00:00 2001
From: Pip Cet <pipcet@gmail.com>
Date: Mon, 22 Jul 2019 03:49:54 +0000
Subject: [PATCH] Don't retry reading after receiving EINVAL (bug#6074)
* src/process.c (wait_reading_process_output): Don't retry reading
from an fd after an unknown error.
---
src/process.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/process.c b/src/process.c
index abadabe77e..1311409274 100644
--- a/src/process.c
+++ b/src/process.c
@@ -5277,7 +5277,9 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
int nread = read_process_output (proc, wait_proc->infd);
if (nread < 0)
{
- if (errno == EIO || would_block (errno))
+ if (errno == EINTR)
+ continue;
+ else
break;
}
else
--
2.22.0
next prev parent reply other threads:[~2019-07-22 3:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-01 22:15 bug#6074: 24.0.50; accept-process-output on listening sockets not incorruptible Helmut Eller
2019-07-22 3:52 ` Pip Cet [this message]
2019-07-22 14:26 ` bug#6074: accept-process-output on listening sockets cause non-interruptible infloop Eli Zaretskii
2019-07-22 17:45 ` Pip Cet
2020-09-14 13:21 ` Lars Ingebrigtsen
2019-07-23 2:46 ` Richard Stallman
2019-07-23 14:31 ` Pip Cet
2019-07-25 3:08 ` Richard Stallman
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