[Pdbg] [PATCH v2 24/39] gdbserver: catch ctrl-C to clean up host state

[Joel Stanley]

On Wed, 20 Apr 2022 at 06:51, Nicholas Piggin <npiggin at gmail.com> wrote:
>
> This allows gdbserver to clean up the host state gracefully after
> a SIGINT. Later patches will add more host state cleanup.
>
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>  src/pdbgproxy.c | 24 ++++++++++++++++++++++--
>  1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/src/pdbgproxy.c b/src/pdbgproxy.c
> index 4572c689..ef8aa479 100644
> --- a/src/pdbgproxy.c
> +++ b/src/pdbgproxy.c
> @@ -4,6 +4,7 @@
>  #include <stdio.h>
>  #include <stdlib.h>
>  #include <string.h>
> +#include <signal.h>
>  #include <fcntl.h>
>  #include <unistd.h>
>  #include <sys/types.h>
> @@ -640,12 +641,28 @@ static command_cb callbacks[LAST_CMD + 1] = {
>         detach,
>         NULL};
>
> -int gdbserver_start(struct pdbg_target *thread, struct pdbg_target *adu, uint16_t port)
> +static volatile bool gdbserver_running = true;

volatile! Is this how we userspace?

Reviewed-by: Joel Stanley <joel at jms.id.au>

> +
> +static void SIGINT_handler(int sig)
> +{
> +       gdbserver_running = false;
> +}
> +
> +static int gdbserver_start(struct pdbg_target *thread, struct pdbg_target *adu, uint16_t port)
>  {
>         int sock, i;
> +       struct sigaction sa;
>         struct sockaddr_in name;
>         fd_set active_fd_set, read_fd_set;
>
> +       memset(&sa, 0, sizeof(sa));
> +       sa.sa_handler = SIGINT_handler;
> +       sa.sa_flags = SA_RESETHAND | SA_NODEFER;
> +       if (sigaction(SIGINT, &sa, NULL) == -1) {
> +               perror("sigaction");
> +               return -1;
> +       }
> +
>         parser_init(callbacks);
>         thread_target = thread;
>         adu_target = adu;
> @@ -674,7 +691,7 @@ int gdbserver_start(struct pdbg_target *thread, struct pdbg_target *adu, uint16_
>         FD_ZERO(&active_fd_set);
>         FD_SET(sock, &active_fd_set);
>
> -       while (1) {
> +       while (gdbserver_running) {
>                 read_fd_set = active_fd_set;
>                 timeout.tv_sec = 0;
>                 timeout.tv_usec = poll_interval;
> @@ -725,6 +742,8 @@ int gdbserver_start(struct pdbg_target *thread, struct pdbg_target *adu, uint16_
>                 poll();
>         }
>
> +       printf("gdbserver: got ctrl-C, cleaning up (second ctrl-C to kill immediately).\n");
> +
>         return 1;
>  }
>
> @@ -776,6 +795,7 @@ static int gdbserver(uint16_t port)
>         }
>
>         gdbserver_start(thread, adu, port);
> +
>         return 0;
>  }
>  #else
> --
> 2.35.1
>
> --
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