Re: [Nbd] [PATCH] nbd-client: do not leave child processes in the zombie state

[Wouter Verhelst <w@...112...>]

On Sat, Jun 16, 2012 at 03:43:23AM +0400, Dmitry V. Levin wrote:
> Change SIGCHLD handler to SIG_DFL with SA_NOCLDWAIT flag set, to avoid
> transforming child processes into zombies when they terminate.  Since
> the main process is inevitably blocked in NBD_DO_IT ioctl at the time
> when child processes terminate, this is the simplest way to get rid of
> zombie processes.

Thanks, applied.

> Signed-off-by: Dmitry V. Levin <ldv@...1147...>
> ---
>  nbd-client.c |   11 +++++++++++
>  1 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/nbd-client.c b/nbd-client.c
> index 7a526b9..2321e7b 100644
> --- a/nbd-client.c
> +++ b/nbd-client.c
> @@ -35,6 +35,7 @@
>  #include <stdlib.h>
>  #include <sys/mount.h>
>  #include <sys/mman.h>
> +#include <signal.h>
>  #include <errno.h>
>  #include <getopt.h>
>  #include <stdarg.h>
> @@ -571,6 +572,16 @@ int main(int argc, char *argv[]) {
>  #endif
>  	do {
>  #ifndef NOFORK
> +#ifdef SA_NOCLDWAIT
> +		struct sigaction sa;
> +
> +		sa.sa_handler = SIG_DFL;
> +		sigemptyset(&sa.sa_mask);
> +		sa.sa_flags = SA_NOCLDWAIT;
> +		if (sigaction(SIGCHLD, &sa, NULL) < 0)
> +			err("sigaction: %m");
> +#endif
> +
>  		if (!fork()) {
>  			/* Due to a race, the kernel NBD driver cannot
>  			 * call for a reread of the partition table
> -- 
> ldv
> 
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