[1/2] busybox: add /dev/std{in, out, err} symlinks to inittab

Message ID 20180404180935.15185-2-joerg.krause@embedded.rocks
State New
Headers show
Series
  • Add /dev/std{in, out, err} symlinks to inittabs
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Commit Message

Jörg Krause April 4, 2018, 6:09 p.m.
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: Jörg Krause <joerg.krause@embedded.rocks>
---
 package/busybox/inittab | 4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/package/busybox/inittab b/package/busybox/inittab
index 3f49f6bd7a..0f6b8cbe37 100644
--- a/package/busybox/inittab
+++ b/package/busybox/inittab
@@ -19,6 +19,10 @@ 
 ::sysinit:/bin/mkdir -p /dev/pts
 ::sysinit:/bin/mkdir -p /dev/shm
 ::sysinit:/bin/mount -a
+::sysinit:/bin/ln -sf /proc/self/fd /dev/fd
+::sysinit:/bin/ln -sf /proc/self/fd/0 /dev/stdin
+::sysinit:/bin/ln -sf /proc/self/fd/1 /dev/stdout
+::sysinit:/bin/ln -sf /proc/self/fd/2 /dev/stderr
 ::sysinit:/bin/hostname -F /etc/hostname
 # now run any rc scripts
 ::sysinit:/etc/init.d/rcS