Re: [PATCH v8] testpmd: cleanup cleanly from signal

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 11/12/2022 5:28 PM, Stephen Hemminger wrote:
> Do a clean shutdown of testpmd when a signal is received;
> instead of having testpmd kill itself.
> This fixes the problem where a signal could be received
> in the middle of a PMD and then the signal handler would call
> PMD's close routine leading to locking problems.
> 
> An added benefit is it gets rid of some Windows specific code.
> 
> Fixes: d9a191a00e81 ("app/testpmd: fix quitting in container")
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
> v8 - fix build on Windows (again)
>      Windows doesn't have FILENO_STDIN
> 
>  app/test-pmd/testpmd.c | 67 +++++++++++++++++++-----------------------
>  1 file changed, 31 insertions(+), 36 deletions(-)
> 
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index aa7ea29f15ba..b4fb6a2bcbcf 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -11,6 +11,7 @@
>  #include <fcntl.h>
>  #ifndef RTE_EXEC_ENV_WINDOWS
>  #include <sys/mman.h>
> +#include <sys/select.h>
>  #endif
>  #include <sys/types.h>
>  #include <errno.h>
> @@ -4224,13 +4225,6 @@ init_port(void)
>  	memset(txring_numa, NUMA_NO_CONFIG, RTE_MAX_ETHPORTS);
>  }
>  
> -static void
> -force_quit(void)
> -{
> -	pmd_test_exit();
> -	prompt_exit();
> -}
> -
>  static void
>  print_stats(void)
>  {
> @@ -4249,28 +4243,9 @@ print_stats(void)
>  }
>  
>  static void
> -signal_handler(int signum)
> +signal_handler(int signum __rte_unused)
>  {
> -	if (signum == SIGINT || signum == SIGTERM) {
> -		fprintf(stderr, "\nSignal %d received, preparing to exit...\n",
> -			signum);
> -#ifdef RTE_LIB_PDUMP
> -		/* uninitialize packet capture framework */
> -		rte_pdump_uninit();
> -#endif
> -#ifdef RTE_LIB_LATENCYSTATS
> -		if (latencystats_enabled != 0)
> -			rte_latencystats_uninit();
> -#endif
> -		force_quit();
> -		/* Set flag to indicate the force termination. */
> -		f_quit = 1;
> -		/* exit with the expected status */
> -#ifndef RTE_EXEC_ENV_WINDOWS
> -		signal(signum, SIG_DFL);
> -		kill(getpid(), signum);
> -#endif
> -	}
> +	f_quit = 1;
>  }

Signal handler used for interactive mode too, that is why
'force_quit();' is still needed in signal handler.

Perhaps different signal handlers can be set for interactive and
non-interactive modes.

>  
>  int
> @@ -4449,9 +4424,6 @@ main(int argc, char** argv)
>  	} else
>  #endif
>  	{
> -		char c;
> -		int rc;
> -
>  		f_quit = 0;
>  
>  		printf("No commandline core given, start packet forwarding\n");
> @@ -4476,15 +4448,38 @@ main(int argc, char** argv)
>  				prev_time = cur_time;
>  				rte_delay_us_sleep(US_PER_S);
>  			}
> -		}
> +		} else {
> +			char c;
> +			fd_set fds;
> +
> +			printf("Press enter to exit\n");
> +
> +			FD_ZERO(&fds);
> +			FD_SET(0, &fds);
>  
> -		printf("Press enter to exit\n");
> -		rc = read(0, &c, 1);
> +			ret = select(1, &fds, NULL, NULL, NULL);
> +			if (ret < 0 && errno != EINTR)
> +				rte_exit(EXIT_FAILURE,
> +					 "Select failed: %s\n",
> +					 strerror(errno));
> +
> +			if (ret == 1 && read(0, &c, 1) < 0)
> +				rte_exit(EXIT_FAILURE,
> +					 "Read failed: %s\n",
> +					 strerror(errno));
> +		}
>  		pmd_test_exit();
> -		if (rc < 0)
> -			return 1;
>  	}
>  
> +#ifdef RTE_LIB_PDUMP
> +	/* uninitialize packet capture framework */
> +	rte_pdump_uninit();
> +#endif
> +#ifdef RTE_LIB_LATENCYSTATS
> +	if (latencystats_enabled != 0)
> +		rte_latencystats_uninit();
> +#endif

+1 to move these functions here, but signal handler for the interactive
mode also needs these functions.

> +
>  	ret = rte_eal_cleanup();
>  	if (ret != 0)
>  		rte_exit(EXIT_FAILURE,