Re: [PATCH 04/24] perf daemon: Add server socket support

[Namhyung Kim]

On Sun, Jan 31, 2021 at 8:49 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Add support to create server socket that listens for client
> commands and process them.
>
> This patch adds only the core support, all commands using
> this functionality are coming in following patches.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/perf/builtin-daemon.c | 101 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 100 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
> index 8d0ac44ec808..756d60616d7d 100644
> --- a/tools/perf/builtin-daemon.c
> +++ b/tools/perf/builtin-daemon.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #include <subcmd/parse-options.h>
> +#include <api/fd/array.h>
>  #include <linux/limits.h>
>  #include <string.h>
>  #include <signal.h>
> @@ -7,6 +8,10 @@
>  #include <stdio.h>
>  #include <unistd.h>
>  #include <errno.h>
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +#include <sys/un.h>
> +#include <poll.h>
>  #include "builtin.h"
>  #include "perf.h"
>  #include "debug.h"
> @@ -37,6 +42,78 @@ static void sig_handler(int sig __maybe_unused)
>         done = true;
>  }
>
> +static int setup_server_socket(struct daemon *daemon)
> +{
> +       struct sockaddr_un addr;
> +       char path[100];
> +       int fd;
> +
> +       fd = socket(AF_UNIX, SOCK_STREAM, 0);
> +       if (fd < 0) {
> +               fprintf(stderr, "socket: %s\n", strerror(errno));
> +               return -1;
> +       }
> +
> +       fcntl(fd, F_SETFD, FD_CLOEXEC);
> +
> +       scnprintf(path, PATH_MAX, "%s/control", daemon->base);

I couldn't find where the default value of daemon->base is set.
Also 100 bytes seem not enough for the path name.

Thanks,
Namhyung

> +
> +       memset(&addr, 0, sizeof(addr));
> +       addr.sun_family = AF_UNIX;
> +
> +       strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1);
> +       unlink(path);
> +
> +       if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
> +               perror("failed: bind");
> +               return -1;
> +       }
> +
> +       if (listen(fd, 1) == -1) {
> +               perror("failed: listen");
> +               return -1;
> +       }
> +
> +       return fd;
> +}