Re: [Qemu-devel] [PATCH 7/8] os-posix: Provide new -runasid option

[Markus Armbruster <armbru@redhat.com>]

Ian Jackson <ian.jackson@eu.citrix.com> writes:

> This allows the caller to specify a uid and gid to use, even if there
> is no corresponding password entry.  This will be useful in certain
> Xen configurations.
>
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
[...]
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 9f6e2ad..34a5329 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -3968,6 +3968,18 @@ Immediately before starting guest execution, drop root privileges, switching
>  to the specified user.
>  ETEXI
>  
> +#ifndef _WIN32
> +DEF("runasid", HAS_ARG, QEMU_OPTION_runasid, \
> +    "-runasid uid.gid     change to numeric uid and gid just before starting the VM\n",
> +    QEMU_ARCH_ALL)
> +#endif
> +STEXI
> +@item -runasid @var{uid}.@var{gid}
> +@findex -runasid
> +Immediately before starting guest execution, drop root privileges, switching
> +to the specified uid and gid.
> +ETEXI
> +
>  DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
>      "-prom-env variable=value\n"
>      "                set OpenBIOS nvram variables\n",

The last thing the QEMU command line needs is more exotic options.  Are
you sure we need a new one here?  Can we make existing -runas serve?
Precedence: Coreutils[*].  Pseudo-code:

    if argument is a decimal number starting with '+':
        user ID
    else if argument is a valid user name:
        user name
    else if argument is a valid user ID:
        user ID
    else:
        error

[*] https://www.gnu.org/software/coreutils/manual/html_node/Disambiguating-names-and-IDs.html