Re: [Qemu-devel] [PATCH] Quote extra_cflags in config-host.mak

[Eric Blake <eblake@redhat.com>]

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On 09/11/2013 08:53 AM, Paolo Bonzini wrote:
> 
> printf "# Configured with:" >> $config_host_mak
> printf " '%s'" "$0" "$@" >> $config_host_mak
> 
> Something like
> 
> for arg in "$0" "$@"; do
>    quoted_arg=$(echo "$i" | sed 's/[$\\"]/\\&/g')

Won't work as written: mismatch between $arg vs. $i.

That missed ` - but do we expect anyone to pass a literal ` as one of
their arguments?  Also, it strips any literal trailing newlines in the
arguments.

>    printf ' "%s"' "$quoted_arg"
> done >> $config_host_mak
> 
> could replace the second line.  Adding Eric Blake in case he knows some
> extra trick.

Nope, no good portable tricks for this.  But to address the (corner
case) issues I mentioned above, it might be worth using '' rather than
"" quoting; as well as embed a trailing space to guarantee no trailing
newline:

for arg in "$0" "$@"; do
    quoted_arg=$(echo "$arg " | sed "s/'/'\\''/g')
    printf "'%s'" "$quoted_arg"
done >> $config_host_mak

if you don't mind a trailing space in the output file.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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