Re: [dpdk-dev] [PATCH v2] app/testpmd: avoid exit without terminal restore

["Yu, DapengX" <dapengx.yu@intel.com>]

Hi Xiaoyun,

For this situation: registering prompt_exit succeed,  and user type "quit" command to exit testpmd.

If the second call to cmdline_stdin_exit is not excluded from the code conditionally, the cmdline_stdin_exit will be called twice;

1. the first time: in prompt()
    #0  cmdline_stdin_exit (cl=0x3638470) at ../lib/librte_cmdline/cmdline_socket.c:56
    #1  0x000000000051fb62 in prompt () at ../app/test-pmd/cmdline.c:17134
    #2  0x00000000005a4d0f in main (argc=2, argv=0x7fffffffda70) at ../app/test-pmd/testpmd.c:3849
2. the second time: in exit() .
    #0  cmdline_stdin_exit (cl=0x3638470) at ../lib/librte_cmdline/cmdline_socket.c:56
    #1  0x000000000051fb95 in prompt_exit () at ../app/test-pmd/cmdline.c:17142
    #2  0x00007ffff630fe9c in __run_exit_handlers () from /lib64/libc.so.6
    #3  0x00007ffff630ffd0 in exit () from /lib64/libc.so.6
    #4  0x00007ffff62f96aa in __libc_start_main () from /lib64/libc.so.6
    #5  0x00000000004ead2e in _start () 

-----Original Message-----
From: Li, Xiaoyun 
Sent: Tuesday, January 26, 2021 2:33 PM
To: Yu, DapengX <dapengx.yu@intel.com>; Xing, Beilei <beilei.xing@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>; Iremonger, Bernard <bernard.iremonger@intel.com>; stephen@networkplumber.org
Cc: dev@dpdk.org; Yu, DapengX <dapengx.yu@intel.com>; stable@dpdk.org
Subject: RE: [PATCH v2] app/testpmd: avoid exit without terminal restore

Hi

> -----Original Message-----
> From: dapengx.yu@intel.com <dapengx.yu@intel.com>
> Sent: Monday, January 25, 2021 11:30
> To: Xing, Beilei <beilei.xing@intel.com>; Li, Xiaoyun 
> <xiaoyun.li@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>; Iremonger, 
> Bernard <bernard.iremonger@intel.com>; stephen@networkplumber.org
> Cc: dev@dpdk.org; Yu, DapengX <dapengx.yu@intel.com>; stable@dpdk.org
> Subject: [PATCH v2] app/testpmd: avoid exit without terminal restore
> 
> From: Dapeng Yu <dapengx.yu@intel.com>
> 
> In interactive mode, if testpmd exit by calling rte_exit without 
> restore terminal attributes, terminal will not echo keyboard input.
> 
> register a function with atexit() in prompt(), when exit() in
> rte_exit() is called, the registered function restores terminal attributes.
> 
> Fixes: 5a8fb55c48ab ("app/testpmd: support unidirectional 
> configuration")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Dapeng Yu <dapengx.yu@intel.com>
> ---
>  app/test-pmd/cmdline.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index 
> 89034c8b7..f7e18ba3d 100644
> --- a/app/test-pmd/cmdline.c
> +++ b/app/test-pmd/cmdline.c
> @@ -17116,6 +17116,7 @@ cmdline_read_from_file(const char *filename) 
> void
>  prompt(void)
>  {
> +int ret;
>  /* initialize non-constant commands */  cmd_set_fwd_mode_init();  
> cmd_set_fwd_retry_mode_init(); @@ -17123,15 +17124,23 @@ prompt(void)  
> testpmd_cl = cmdline_stdin_new(main_ctx, "testpmd> ");  if (testpmd_cl 
> == NULL)  return;
> +
> +ret = atexit(prompt_exit);
> +if (ret != 0)
> +printf("Cannot set exit function for cmdline\n");
> +
>  cmdline_interact(testpmd_cl);
> -cmdline_stdin_exit(testpmd_cl);
> +if (ret != 0)

Why do you need to check ret here?
Even if registers prompt_exit failed, when users type "quit" and then break from cmdline_interact(), cmdline_stdin_exit() should be called to restore terminal settings.

> +cmdline_stdin_exit(testpmd_cl);
>  }
> 
>  void
>  prompt_exit(void)
>  {
> -if (testpmd_cl != NULL)
> +if (testpmd_cl != NULL) {
>  cmdline_quit(testpmd_cl);
> +cmdline_stdin_exit(testpmd_cl);
> +}
>  }
> 
>  static void
> --
> 2.27.0