[lxc-devel] [PATCH 14/21] Make utmpx.h optional

[Serge Hallyn]

Quoting Stéphane Graber (stgraber at ubuntu.com):
> This adds code detecting the presence of utmpx.h and in its absence, turns the
> utmp related functions into no-ops.
> 
> Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
> ---
>  configure.ac   | 2 +-
>  src/lxc/utmp.c | 7 +++++++
>  src/lxc/utmp.h | 9 +++++++++
>  3 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 2905aee..5b7573a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -211,7 +211,7 @@ AM_CONDITIONAL([IS_BIONIC], [test "x$libc_type" = "xbionic"])
>  AC_CHECK_DECLS([PR_CAPBSET_DROP], [], [], [#include <sys/prctl.h>])
>  
>  # Check for some headers
> -AC_CHECK_HEADERS([sys/signalfd.h sys/personality.h sys/capability.h pty.h])
> +AC_CHECK_HEADERS([sys/signalfd.h sys/personality.h sys/capability.h pty.h utmpx.h])
>  
>  # Check for some functions
>  AC_CHECK_FUNCS([getline fgetln openpty setns pivot_root sethostname unshare])
> diff --git a/src/lxc/utmp.c b/src/lxc/utmp.c
> index a7b9b52..16d1b5d 100644
> --- a/src/lxc/utmp.c
> +++ b/src/lxc/utmp.c
> @@ -21,6 +21,10 @@
>   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
>   */
>  
> +#include "config.h"
> +
> +#ifdef HAVE_UTMPX_H
> +
>  #include <stdio.h>
>  #include <unistd.h>
>  #include <errno.h>
> @@ -37,6 +41,7 @@
>  #include "mainloop.h"
>  #include "lxc.h"
>  #include "log.h"
> +
>  #define __USE_GNU
>  #include <utmpx.h>
>  #undef __USE_GNU
> @@ -410,3 +415,5 @@ int lxc_utmp_del_timer(struct lxc_epoll_descr *descr,
>  	else
>  		return 0;
>  }
> +
> +#endif
> diff --git a/src/lxc/utmp.h b/src/lxc/utmp.h
> index ac3eee4..ad4a8ab 100644
> --- a/src/lxc/utmp.h
> +++ b/src/lxc/utmp.h
> @@ -21,8 +21,17 @@
>   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
>   */
>  
> +#include "config.h"
> +
>  struct lxc_handler;
>  struct lxc_epoll_descr;
>  
> +#ifdef HAVE_UTMPX_H
>  int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
>  			  struct lxc_handler *handler);
> +#else
> +static inline int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
> +			  struct lxc_handler *handler) {
> +		return 0;

Would it be better to return -1 here?  This will only be called if
the containerized reboot isn't available, in which case not having
the utmp watcher to fall back on rather sucks.

I guess it's not that big a deal, just makes reboot/shutdown in
the container not work...

> +}
> +#endif
> -- 
> 1.8.0
> 
> 
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