Re: [PATCH v2 1/4] os-posix: Add os_set_daemonize()

[Eric Blake <eblake@redhat.com>]

On Thu, Mar 03, 2022 at 05:48:11PM +0100, Hanna Reitz wrote:
> The daemonizing functions in os-posix (os_daemonize() and
> os_setup_post()) only daemonize the process if the static `daemonize`
> variable is set.  Right now, it can only be set by os_parse_cmd_args().
> 
> In order to use os_daemonize() and os_setup_post() from the storage
> daemon to have it be daemonized, we need some other way to set this
> `daemonize` variable, because I would rather not tap into the system
> emulator's arg-parsing code.  Therefore, this patch adds an
> os_set_daemonize() function, which will return an error on os-win32
> (because daemonizing is not supported there).
> 
> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
> ---

> +++ b/include/sysemu/os-win32.h
> @@ -77,6 +77,11 @@ typedef struct {
>  } qemu_timeval;
>  int qemu_gettimeofday(qemu_timeval *tp);
>  
> +static inline int os_set_daemonize(bool d)
> +{
> +    return -ENOTSUP;

Should this fail only if d is true?  Or will all callers only ever
pass true, in which case why do we need the paraemeter?

> +}
> +
>  static inline bool is_daemonized(void)
>  {
>      return false;
> diff --git a/os-posix.c b/os-posix.c
> index ae6c9f2a5e..24692c8593 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -317,6 +317,12 @@ bool is_daemonized(void)
>      return daemonize;
>  }
>  
> +int os_set_daemonize(bool d)
> +{
> +    daemonize = d;
> +    return 0;
> +}
> +
>  int os_mlock(void)
>  {
>  #ifdef HAVE_MLOCKALL
> -- 
> 2.34.1
> 
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org