[libvirt] [PATCHv3] build: fix shell detection bug

[Matthias Bolte]

2010/10/26 Eric Blake <eblake at redhat.com>:
> A missing shell was noisy, and the use of command to decipher a
> shell's absolute path requires "" rather than ''.
>
> * configure.ac (lv_cv_wrapper_shell): Fix logic errors if candidate
> shell is not available.  Define a C string literal, not raw tokens.
> Reported by Matthias Bolte.
> ---
>
> Fixed in v3: the AC_DEFINE needs to output a string literal
> rather than raw text.
>
> Fixed in v2: don't call command -v on an empty substitution
>
> Actually tested by myself this time rather than relying on others, by
> manually overriding my /bin/sh with a broken dash, and double-checking
> the resulting config.h.
>
>  configure.ac |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index 86a864b..d942d3c 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -616,13 +616,13 @@ if test "$with_qemu" = yes; then
>         test $lv_cv_wrapper_shell = none &&
>           AC_MSG_ERROR([could not find decent shell])
>         echo a > conftest.a
> -        $lv_cv_wrapper_shell -c ': 1<>conftest.a'
> +        ($lv_cv_wrapper_shell -c ': 1<>conftest.a') 2>/dev/null &&
>         case `cat conftest.a`.$lv_cv_wrapper_shell in
>           a./*) break;; dnl /bin/sh is good enough
>           a.*) dnl bash, ksh, and zsh all understand 'command', use that
>                dnl to determine the absolute path of the shell
>             lv_cv_wrapper_shell=`$lv_cv_wrapper_shell -c \
> -              'command -v $lv_cv_wrapper_shell'`
> +              "command -v $lv_cv_wrapper_shell"`
>             case $lv_cv_wrapper_shell in
>               /*) break;;
>             esac
> @@ -636,7 +636,7 @@ if test "$with_qemu" = yes; then
>     lv_wrapper_shell=$lv_cv_wrapper_shell
>   fi
>   if test "x$lv_wrapper_shell" != x; then
> -    AC_DEFINE_UNQUOTED([VIR_WRAPPER_SHELL], [$lv_wrapper_shell],
> +    AC_DEFINE_UNQUOTED([VIR_WRAPPER_SHELL], ["$lv_wrapper_shell"],
>       [Define to the absolute path of a shell that does not truncate on
>        <> redirection, if /bin/sh does not fit the bill])
>   fi
> --
> 1.7.2.3
>

Tested on Ubuntu 10.04 with broken dash.

ACK.

Matthias