Re: [PATCH v2] xenstore: create pidfile in init-xenstore-domain

[Christoph Egger <chegger@amazon.de>]

On 24.04.13 18:44, Daniel De Graaf wrote:
> Since libxl checks for the existance of /var/run/xenstored.pid in order
> to ensure xenstore is running, create this file when starting the
> xenstore stub domain. This also changes the Makefile to enable the
> creation of the init-xenstore-domain tool during tools compilation,
> since the existing Makefile incorrectly added to the ALL_TARGETS list
> when compiling the stubdom, when this variable is not used.
> 
> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
> ---
>  tools/xenstore/Makefile               |  5 ++++-
>  tools/xenstore/init-xenstore-domain.c | 12 +++++++++++-
>  2 files changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/xenstore/Makefile b/tools/xenstore/Makefile
> index 9172d3a..1bb6e58 100644
> --- a/tools/xenstore/Makefile
> +++ b/tools/xenstore/Makefile
> @@ -29,9 +29,12 @@ endif
>  
>  ALL_TARGETS = libxenstore.so libxenstore.a clients xs_tdb_dump xenstored
>  
> +ifeq ($(CONFIG_Linux),y)
> +ALL_TARGETS += init-xenstore-domain
> +endif
> +

Please explain what is Linux-specific?

>  ifdef CONFIG_STUBDOM
>  CFLAGS += -DNO_SOCKETS=1
> -ALL_TARGETS += init-xenstore-domain
>  endif
>  
>  .PHONY: all
> diff --git a/tools/xenstore/init-xenstore-domain.c b/tools/xenstore/init-xenstore-domain.c
> index 18c075b..35f1aa3 100644
> --- a/tools/xenstore/init-xenstore-domain.c
> +++ b/tools/xenstore/init-xenstore-domain.c
> @@ -1,4 +1,5 @@
>  #include <fcntl.h>
> +#include <unistd.h>
>  #include <stdio.h>
>  #include <string.h>
>  #include <stdint.h>
> @@ -69,7 +70,7 @@ int main(int argc, char** argv)
>  	xc_interface *xch;
>  	struct xs_handle *xsh;
>  	char buf[16];
> -	int rv;
> +	int rv, fd;
>  
>  	if (argc != 4) {
>  		printf("Use: %s <xenstore-kernel> <memory_mb> <flask-label>\n", argv[0]);
> @@ -90,5 +91,14 @@ int main(int argc, char** argv)
>  	xs_write(xsh, XBT_NULL, "/tool/xenstored/domid", buf, rv);
>  	xs_daemon_close(xsh);
>  
> +	fd = creat("/var/run/xenstored.pid", 0666);
> +	if (fd < 0)
> +		return 3;
> +	rv = snprintf(buf, 16, "domid:%d\n", domid);

Use sizeof(buf). That's less error-prone whenever the size
of buf changes.

> +	rv = write(fd, buf, rv);
> +	close(fd);
> +	if (rv < 0)
> +		return 3;
> +
>  	return 0;
>  }
>