From: Peter Korsgaard <peter@korsgaard.com>
Date: Sun, 17 Jun 2018 17:58:37 +0200
Subject: [Buildroot] [PATCH 2/2] sysvinit: add /dev/std{in, out,
 err} symlinks to inittab
In-Reply-To: <87efivf8zk.fsf@dell.be.48ers.dk> (Peter Korsgaard's message of
 "Tue, 01 May 2018 21:53:35 +0200")
References: <20180404180935.15185-1-joerg.krause@embedded.rocks>
 <20180404180935.15185-3-joerg.krause@embedded.rocks>
 <87efivf8zk.fsf@dell.be.48ers.dk>
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List-Id: <buildroot.busybox.net>
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To: buildroot@busybox.net

>>>>> "Peter" == Peter Korsgaard <peter@korsgaard.com> writes:

>>>>> "J?rg" == J?rg Krause <joerg.krause@embedded.rocks> writes:
 >> Some applications, e.g. bashs process subsitution feature, rely on the
 >> convention of `/dev/fd` being a symbolic link to `/proc/self/fd`.

 >> This symbolic link and his companions `/dev/std*` are created by (e)udev [1],
 >> but not by mdev, resulting in the following error when using the following
 >> expression:

 >> ```
 >> bash: /dev/fd/62: No such file or directory
 >> ```

 >> For the sake of simplicity, lets fix this by creating the symlinks in inittab.
 >> It is only really needed if eudev isn't used, but it doesn't really hurt to
 >> create them even if eudev will recreate them afterwards.

 >> Note, that we do not create the symlink `/dev/core` as `/proc/kcore` is
 >> not available on all platforms, e.g. ARM, and the feature is not much
 >> appreciated [2].

 >> [1]
 >> https://github.com/gentoo/eudev/blob/8943501993322c59a6eb5be456b0d716aafff21e/src/shared/dev-setup.c#L35-L40
 >> [2] https://lwn.net/Articles/45315/

 >> Signed-off-by: J?rg Krause <joerg.krause@embedded.rocks>
 >> ---
 >> package/sysvinit/inittab | 6 +++++-
 >> 1 file changed, 5 insertions(+), 1 deletion(-)

 >> diff --git a/package/sysvinit/inittab b/package/sysvinit/inittab
 >> index fad91eae8b..608aabce07 100644
 >> --- a/package/sysvinit/inittab
 >> +++ b/package/sysvinit/inittab
 >> @@ -9,7 +9,11 @@ si1::sysinit:/bin/mount -o remount,rw /
 >> si2::sysinit:/bin/mkdir -p /dev/pts
 >> si3::sysinit:/bin/mkdir -p /dev/shm
 >> si4::sysinit:/bin/mount -a
 >> -si5::sysinit:/bin/hostname -F /etc/hostname
 >> +si5::sysinit:/bin/ln -sf /proc/self/fd /dev/fd
 >> +si6::sysinit:/bin/ln -sf /proc/self/fd/0 /dev/stdin
 >> +si7::sysinit:/bin/ln -sf /proc/self/fd/1 /dev/stdout
 >> +si8::sysinit:/bin/ln -sf /proc/self/fd/2 /dev/stderr

 > This will fail on static /dev on a readonly rootfs, so I've redirected
 > errors to /dev/null.

 > Committed with that changed, thanks.

 > I have also added a patch adding these symlinks in the default skeleton
 > to handle static /dev on readonly rootfs setups.

Committed to 2018.02.x, thanks.

-- 
Bye, Peter Korsgaard