Re: [PATCH 05/24] perf daemon: Add client socket support

[Namhyung Kim <namhyung@kernel.org>]

On Sun, Jan 31, 2021 at 8:49 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding support for client socket side that will be used
> to send commands to daemon server socket.
>
> This patch adds only the core support, all commands using
> this functionality are coming in following patches.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/builtin-daemon.c | 105 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 105 insertions(+)
>
> diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
> index 756d60616d7d..eada3ceb9b0c 100644
> --- a/tools/perf/builtin-daemon.c
> +++ b/tools/perf/builtin-daemon.c
> @@ -11,6 +11,7 @@
>  #include <sys/types.h>
>  #include <sys/socket.h>
>  #include <sys/un.h>
> +#include <sys/stat.h>
>  #include <poll.h>
>  #include "builtin.h"
>  #include "perf.h"
> @@ -42,6 +43,50 @@ static void sig_handler(int sig __maybe_unused)
>         done = true;
>  }
>
> +static int client_config(const char *var, const char *value, void *cb)
> +{
> +       struct daemon *daemon = cb;
> +
> +       if (!strcmp(var, "daemon.base") && !daemon->base_user) {
> +               daemon->base = strdup(value);
> +               if (!daemon->base)
> +                       return -ENOMEM;
> +       }
> +
> +       return 0;
> +}
> +
> +static int check_base(struct daemon *daemon)
> +{
> +       struct stat st;
> +
> +       if (!daemon->base) {
> +               pr_err("failed: base not defined\n");
> +               return -EINVAL;
> +       }
> +
> +       if (stat(daemon->base, &st)) {
> +               pr_err("failed: base '%s' does not exists\n", daemon->base);

Well, it could be a permission error or something..

> +               return -EINVAL;
> +       }

You may also check whether it's a directory.

> +
> +       return 0;
> +}
> +
> +static int setup_client_config(struct daemon *daemon)
> +{
> +       struct perf_config_set *set;
> +       int err = -ENOMEM;
> +
> +       set = perf_config_set__load_file(daemon->config_real);
> +       if (set) {
> +               err = perf_config_set(set, client_config, daemon);
> +               perf_config_set__delete(set);
> +       }
> +
> +       return err ?: check_base(daemon);
> +}
> +
>  static int setup_server_socket(struct daemon *daemon)
>  {
>         struct sockaddr_un addr;
> @@ -114,6 +159,32 @@ static int handle_server_socket(struct daemon *daemon __maybe_unused, int sock_f
>         return ret;
>  }
>
> +static int setup_client_socket(struct daemon *daemon)
> +{
> +       struct sockaddr_un addr;
> +       char path[100];
> +       int fd;
> +
> +       fd = socket(AF_UNIX, SOCK_STREAM, 0);
> +       if (fd == -1) {
> +               perror("failed: socket");
> +               return -1;
> +       }
> +
> +       scnprintf(path, PATH_MAX, "%s/control", daemon->base);

Same as the previous patch.  The path is 100 bytes..

Thanks,
Namhyung

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