Em Sun, Jan 31, 2021 at 12:48:36AM +0100, Jiri Olsa escreveu:
> 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 <jo...@kernel.org>
> ---
> 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);
Minor, combine decl with use, since line isn't long and its one after
the other, i.e.:
int 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);
Don't we have to check its return?
> +
> + scnprintf(path, PATH_MAX, "%s/control", daemon->base);
Humm the safe thing here is to use:
scnprintf(path, sizeof(path), "%s/control", daemon->base);
Using it like that would avoid the bug in your code, as path has only
100 bytes, not PATH_MAX bytes ;-)
> +
> + memset(&addr, 0, sizeof(addr));
> + addr.sun_family = AF_UNIX;
> +
> + strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1);
strncpy may end up not adding the final \0 see the NOTES in its man
page. Consider using strlcpy instead. See:
bef0b8970f27da5c ("perf probe: Fix unchecked usage of strncpy()")
> + 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;
> +}
> +
> +union cmd {
> + int cmd;
> +};
> +
> +static int handle_server_socket(struct daemon *daemon __maybe_unused, int
> sock_fd)
> +{
> + int ret = -EINVAL, fd;
> + union cmd cmd;
> + FILE *out;
> +
> + fd = accept(sock_fd, NULL, NULL);
> + if (fd < 0) {
> + fprintf(stderr, "accept: %s\n", strerror(errno));
> + return -1;
> + }
> +
> + if (sizeof(cmd) != read(fd, &cmd, sizeof(cmd))) {
> + fprintf(stderr, "read: %s\n", strerror(errno));
close fd
> + return -1;
> + }
> +
> + out = fdopen(fd, "w");
> + if (!out) {
> + perror("failed: fdopen");
close fd
I.e. goto out_close;
> + return -1;
> + }
> +
> + switch (cmd.cmd) {
> + default:
> + break;
> + }
> +
> + fclose(out);
out_close:
> + close(fd);
> + return ret;
> +}
> +
> static void daemon__free(struct daemon *daemon)
> {
> free(daemon->config_real);
> @@ -82,6 +159,9 @@ static int __cmd_start(struct daemon *daemon, struct
> option parent_options[],
> OPT_PARENT(parent_options),
> OPT_END()
> };
> + int sock_fd = -1;
> + int sock_pos;
> + struct fdarray fda;
> int err = 0;
>
> argc = parse_options(argc, argv, start_options, daemon_usage, 0);
> @@ -98,15 +178,34 @@ static int __cmd_start(struct daemon *daemon, struct
> option parent_options[],
>
> pr_info("daemon started (pid %d)\n", getpid());
>
> + fdarray__init(&fda, 1);
> +
> + sock_fd = setup_server_socket(daemon);
> + if (sock_fd < 0)
> + goto out;
> +
> + sock_pos = fdarray__add(&fda, sock_fd, POLLIN|POLLERR|POLLHUP, 0);
> + if (sock_pos < 0)
> + goto out;
> +
> signal(SIGINT, sig_handler);
> signal(SIGTERM, sig_handler);
>
> while (!done && !err) {
> - sleep(1);
> + if (fdarray__poll(&fda, -1)) {
> + if (fda.entries[sock_pos].revents & POLLIN)
> + err = handle_server_socket(daemon, sock_fd);
> + }
> }
>
> +out:
> + fdarray__exit(&fda);
> +
> daemon__exit(daemon);
>
> + if (sock_fd != -1)
> + close(sock_fd);
> +
> pr_info("daemon exited\n");
> fclose(daemon->out);
> return err;
> --
> 2.29.2
>
--
- Arnaldo
