[Buildroot] [RFC] merge_config.sh creates files in buildroot source directory

From: Yann E. MORIN <yann.morin.1998@free.fr>
To: buildroot@busybox.net
Subject: [Buildroot] [RFC] merge_config.sh creates files in buildroot source directory
Date: Thu, 13 Aug 2015 01:50:14 +0200	[thread overview]
Message-ID: <20150812235014.GB3690@free.fr> (raw)
In-Reply-To: <55CBC929.8020101@mentor.com>

Hollis, All,

On 2015-08-12 15:31 -0700, Hollis Blanchard spake thusly:
> A co-worker had a problem where their Linux .config did not at all match
> BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE ("board-layer/linux/board.defconfig"
> below). The problem turned out to be that merge_config.sh was failing. (Side
> note: it failed poorly; the build completed "successfully.")

Ah, indded, that's bad behaviour... :-(

> merge_config.sh is invoked from the root of the Buildroot source tree, and
> attempts to create a temporary file there. This is a problem for my team
> because our Buildroot source tree is shared, and read-only for most users.
> The problem seems to affect all kconfig projects, including Linux and
> busybox.
> 
> support/kconfig/merge_config.sh -m -O /.../output/build/linux-4.0 /.../board-layer/linux/board.defconfig
> mktemp: cannot create temp file ./.tmp.config.YIXmE19452: Permission denied
> Using /.../board-layer/linux/board.defconfig as base
> support/kconfig/merge_config.sh: line 88: $TMP_FILE: ambiguous redirect
> cp: missing destination file operand after `/.../output/build/linux-4.0/.config'
> Try `cp --help' for more information.
> #
> # merged configuration written to /.../output/build/linux-4.0/.config (needs make)
> 
> 
> Invoking mktemp with --tmpdir seems to resolve the problem, but I haven't
> investigated more deeply than that.
> 
> diff --git a/support/kconfig/merge_config.sh b/support/kconfig/merge_config.sh
> index 81b0c61..5beb79d 100755
> --- a/support/kconfig/merge_config.sh
> +++ b/support/kconfig/merge_config.sh
> @@ -82,7 +82,7 @@ shift;
>  MERGE_LIST=$*
>  SED_CONFIG_EXP="s/^\(# \)\{0,1\}\(CONFIG_[a-zA-Z0-9_]*\)[= ].*/\2/p"
> -TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX)
> +TMP_FILE=$(mktemp --tmpdir ./.tmp.config.XXXXXXXXXX)

From man mktemp:

    --tmpdir[=DIR]
        interpret TEMPLATE relative to DIR. If DIR is not specified, use
        $TMPDIR if set, else /tmp. With this option, TEMPLATE must not
        be an absolute name. Unlike with -t, TEMPLATE may contain
        slashes, but mktemp creates only the final component

So, it should probably be:

    TMP_FILE=$(mktemp --tmpdir .tmp.config.XXXXXXXXXX)

Otherwise, looks sane to me.

Care to fix and submit as a proper patch, please?

Regards,
Yann E. MORIN.

>  echo "Using $INITFILE as base"
>  cat $INITFILE > $TMP_FILE
> 
> 
> -- 
> Hollis Blanchard
> Mentor Graphics Emulation Division
> 
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

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