Re: [B.A.T.M.A.N.] [PATCH 2/3] alfred: Add support for network namespaces

[Simon Wunderlich <sw@simonwunderlich.de>]

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On Thursday 28 January 2016 04:53:14 Andrew Lunn wrote:
> When running within a network namespace, access to files within
> debugfs have to take into account the network name space. Each
> namespace has its own directory under
> /sys/kernel/debug/batman_adv/netns.
> 
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> ---
>  batadv_query.c |  2 +-
>  debugfs.c      | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  vis/vis.h      |  2 +-
>  3 files changed, 50 insertions(+), 3 deletions(-)
> 
> diff --git a/batadv_query.c b/batadv_query.c
> index c289b80..fe7c007 100644
> --- a/batadv_query.c
> +++ b/batadv_query.c
> @@ -31,7 +31,7 @@
>  #include <sys/types.h>
>  #include "debugfs.h"
> 
> -#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s"
> +#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s%s"
>  #define DEBUG_TRANSTABLE_GLOBAL "transtable_global"
>  #define DEBUG_ORIGINATORS "originators"
> 
> diff --git a/debugfs.c b/debugfs.c
> index fc39322..35c1bdf 100644
> --- a/debugfs.c
> +++ b/debugfs.c
> @@ -20,11 +20,15 @@
> 
>  #include "debugfs.h"
>  #include <errno.h>
> +#include <fcntl.h>
> +#include <limits.h>
>  #include <stdio.h>
>  #include <string.h>
>  #include <sys/mount.h>
>  #include <sys/stat.h>
>  #include <sys/statfs.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> 
>  #ifndef DEBUGFS_MAGIC
>  #define DEBUGFS_MAGIC          0x64626720
> @@ -42,16 +46,59 @@ static const char *debugfs_known_mountpoints[] = {
>  	NULL,
>  };
> 
> +/* Return the current net namespace number. 0 is never a valid
> + * namespace, so use it to return that there is no name space
> + * support.
> + */
> +
> +static unsigned int debugfs_get_netns_inum(void)
> +{
> +	char net_path[] = "/proc/self/ns/net";
> +	struct stat netst;
> +	int netns;
> +
> +	netns = open(net_path, O_RDONLY);
> +	if (netns < 0) {
> +		if (errno == ENOENT)
> +			/* Probably means no netns support in the kernel */
> +			return 0;
> +
> +		fprintf(stderr,
> +			"Error - can't open /proc/self/ns/net for read: %s\n",
> +			strerror(errno));
> +		return 0;
> +	}
> +
> +	if (fstat(netns, &netst) < 0) {
> +		fprintf(stderr, "Stat of netns failed: %s\n",
> +			strerror(errno));
> +		return 0;

Aren't we leaking the netns file descriptor here? You could just set 
netst.st_ino = 0 instead ...

Rest looks good to me :)

Cheers,
    Simon

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