Bug#710709: debootstrap: consider creating (dangling) /etc/mtab symlink

[Ben Hutchings]

On Wed, 2019-05-01 at 05:01 +0900, Hideki Yamane wrote:
> control: tags -1 +patch
> 
> revised patch
> 
> > From 55c21c166959a93b961c572d5f366d35d054ce24 Mon Sep 17 00:00:00 2001
> From: Hideki Yamane 
> Date: Wed, 1 May 2019 04:24:43 +0900
> Subject: [PATCH] create symlink from /proc/self/mounts to /etc/mtab
> 
> With old kernel version, there is /proc/mounts instead of
> /proc/self/mounts, so check whether /proc/self exists

This is silly, /proc/self has existed since Linux 0.99 and
/proc/self/mounts since Linux 2.5.1.2.

Ben.

> ---
>  functions | 7 +++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/functions b/functions
> index 24f0357..46ebceb 100644
> --- a/functions
> +++ b/functions
> @@ -1176,6 +1176,13 @@ setup_proc () {
>   in_target mount -t sysfs sysfs /sys || true
>   umount_on_exit /sys
>   fi
> + if [ ! -f "$TARGET/etc/mtab" ]; then
> + if [ -L "$TARGET/proc/self" ]; then
> + cd "$TARGET/etc" && ln -s ../proc/self/mounts 
> mtab
> + elif [ -f "$TARGET/proc/mounts" ]; then
> + cd "$TARGET/etc" && ln -s ../proc/mounts mtab
> + fi
> + fi
>   on_exit clear_mtab
>   ;;
>   esac
-- 
Ben Hutchings
Anthony's Law of Force: Don't force it, get a larger hammer.



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Bug#710709: debootstrap: consider creating (dangling) /etc/mtab symlink

[Tianon Gravi]

On Tue, 30 Apr 2019 at 13:03, Hideki Yamane  wrote:
> +   if [ ! -f "$TARGET/etc/mtab" ]; then
> +   if [ -L "$TARGET/proc/self" ]; then
> +   cd "$TARGET/etc" && ln -s ../proc/self/mounts 
> mtab
> +   elif [ -f "$TARGET/proc/mounts" ]; then
> +   cd "$TARGET/etc" && ln -s ../proc/mounts mtab
> +   fi
> +   fi

Not sure I understand the motivation for the "cd" invocations here --
just making a symlink shouldn't need that, right?

| ln -s ../proc/self/mounts "$TARGET/etc/mtab"

(Since a symlink is essentially just a special-typed plain text file
and "ln -s" doesn't really care about the working directory except for
interpreting the final target argument if it's relative.)

♥,
- Tianon
  4096R / B42F 6819 007F 00F8 8E36  4FD4 036A 9C25 BF35 7DD4

Bug#710709: debootstrap: consider creating (dangling) /etc/mtab symlink

[Hideki Yamane]

control: tags -1 +patch

revised patch

>From 55c21c166959a93b961c572d5f366d35d054ce24 Mon Sep 17 00:00:00 2001
From: Hideki Yamane 
Date: Wed, 1 May 2019 04:24:43 +0900
Subject: [PATCH] create symlink from /proc/self/mounts to /etc/mtab

With old kernel version, there is /proc/mounts instead of
/proc/self/mounts, so check whether /proc/self exists
---
 functions | 7 +++
 1 file changed, 7 insertions(+)

diff --git a/functions b/functions
index 24f0357..46ebceb 100644
--- a/functions
+++ b/functions
@@ -1176,6 +1176,13 @@ setup_proc () {
in_target mount -t sysfs sysfs /sys || true
umount_on_exit /sys
fi
+   if [ ! -f "$TARGET/etc/mtab" ]; then
+   if [ -L "$TARGET/proc/self" ]; then
+   cd "$TARGET/etc" && ln -s ../proc/self/mounts 
mtab
+   elif [ -f "$TARGET/proc/mounts" ]; then
+   cd "$TARGET/etc" && ln -s ../proc/mounts mtab
+   fi
+   fi
on_exit clear_mtab
;;
esac
-- 
2.20.1

Bug#710709: debootstrap: consider creating (dangling) /etc/mtab symlink

[Christoph Anton Mitterer]

Package: debootstrap
Version: 1.0.52
Severity: wishlist


Hi.

Perhaps it would make sense if:
/etc/mtab - /proc/mounts
was created by debootstrap as a dangling symlink.

Seems not to be worse than not having mtab at all, and when one
bind mounts /proc to the chroot, than it works out of the box.


Or perhaps /etc/mtab should become part of some base backage?


Cheers,
Chris


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