Hi.
I'll try to produce a full reproducer tomorrow, but the issue we had was when the commands were being executed from sshd, the command that was put into the background would still have the files open from sshd, so sshd would think that it's commands were still running. The below is untested, but shows the general idea. z1.sh ===== z2.sh </dev/null >/dev/null 2>/dev/null & echo Ok z2.sh ===== ls -l /proc/$$/fd >z2.out1 2>&1 ls -l /proc/self/fd >z2.out2 2>&1 sleep 60 If the two above files are on the machine test, doing ssh user@test "z1.sh" should return before the 60 second sleep has expired. It does with busybox 1.24, it doesn't with busybox 1.28. Regards, Mark ________________________________ From: Denys Vlasenko <vda.li...@googlemail.com> Sent: March 28, 2018 17:06 To: Mark Marshall Cc: busybox Subject: Re: [PATCH 1/2] ash: Set the CLOEXEC bit in fcntl_F_DUPFD On Mon, Mar 19, 2018 at 10:31 AM, <mark.marsh...@omicronenergy.com> wrote: > From: Mark Marshall <mark.marsh...@omicronenergy.com> > > The function fcntl_F_DUPFD was introduced as some re-factoring at commit > 035486c7500c09616a6c1040d8e70923532a5c2d > "ash: significant overhaul of redirect saving logic". > The old code used to set the CLOEXEC bit, but this got lost in the > re-factoring, so this change makes the new code do the same. > > This was found because if a script was run via ssh, and this script ran > a second script, redirecting its stdin and stdout, and putting it into > the background, the ssh would hang waiting for the backgrounded script > to terminate. From /proc/999/fd it can be seen that the background script > still has the stdin pipe from sshd open (at file handle 10+). Please provide a reproducer. I tried this: z1 == ./busybox ash z2 </dev/null >/dev/null 2>/dev/null & echo Ok z2 == ls -l /proc/$$/fd >z2.out1 2>&1 ls -l /proc/self/fd >z2.out2 2>&1 I do see some extra fds. The thing is, when I try it, there is no difference before and after commit 035486c7500c09616a6c1040d8e70923532a5c2d.
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