[lxc-devel] [PATCH] only re-open fds if stdin is a tty

[Stéphane Graber]

On Fri, Oct 30, 2015 at 05:14:12AM +0000, Serge Hallyn wrote:
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>

Acked-by: Stéphane Graber <stgraber at ubuntu.com>

> ---
>  src/lxc/lxc_usernsexec.c | 30 ++++++++++++++++--------------
>  1 file changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/src/lxc/lxc_usernsexec.c b/src/lxc/lxc_usernsexec.c
> index 26608d6..37d92fb 100644
> --- a/src/lxc/lxc_usernsexec.c
> +++ b/src/lxc/lxc_usernsexec.c
> @@ -278,20 +278,22 @@ int main(int argc, char *argv[])
>  	memset(ttyname0, '\0', sizeof(ttyname0));
>  	memset(ttyname1, '\0', sizeof(ttyname1));
>  	memset(ttyname2, '\0', sizeof(ttyname2));
> -	ret = readlink("/proc/self/fd/0", ttyname0, sizeof(ttyname0));
> -	if (ret < 0) {
> -		perror("unable to open stdin.");
> -		exit(1);
> -	}
> -	ret = readlink("/proc/self/fd/1", ttyname1, sizeof(ttyname1));
> -	if (ret < 0) {
> -		printf("Warning: unable to open stdout, continuing.");
> -		memset(ttyname1, '\0', sizeof(ttyname1));
> -	}
> -	ret = readlink("/proc/self/fd/2", ttyname2, sizeof(ttyname2));
> -	if (ret < 0) {
> -		printf("Warning: unable to open stderr, continueing.");
> -		memset(ttyname2, '\0', sizeof(ttyname2));
> +	if (isatty(0)) {
> +		ret = readlink("/proc/self/fd/0", ttyname0, sizeof(ttyname0));
> +		if (ret < 0) {
> +			perror("unable to open stdin.");
> +			exit(1);
> +		}
> +		ret = readlink("/proc/self/fd/1", ttyname1, sizeof(ttyname1));
> +		if (ret < 0) {
> +			printf("Warning: unable to open stdout, continuing.");
> +			memset(ttyname1, '\0', sizeof(ttyname1));
> +		}
> +		ret = readlink("/proc/self/fd/2", ttyname2, sizeof(ttyname2));
> +		if (ret < 0) {
> +			printf("Warning: unable to open stderr, continueing.");
> +			memset(ttyname2, '\0', sizeof(ttyname2));
> +		}
>  	}
>  
>  	lxc_list_init(&active_map);
> -- 
> 2.5.0
> 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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