Adding support to detect daemon's config file changes and re-read the configuration when that happens.
Using inotify file descriptor plugged into the main fdarray object for polling. Example: # cat ~/.perfconfig [daemon] base=/opt/perfdata [session-cycles] run = -m 10M -e cycles --overwrite --switch-output -a Starting the daemon: # perf daemon start Check sessions: # perf daemon [772262:daemon] base: /opt/perfdata [772263:cycles] perf record -m 10M -e cycles --overwrite --switch-output -a Change '-m 10M' to '-m 20M', and check daemon log: # tail -f /opt/perfdata/output [2021-01-02 20:31:41.234045] daemon started (pid 772262) [2021-01-02 20:31:41.235072] reconfig: ruining session [cycles:772263]: -m 10M -e cycles --overwrite --switch-output -a [2021-01-02 20:32:08.310137] reconfig: session 'cycles' killed [2021-01-02 20:32:08.310847] reconfig: ruining session [cycles:772338]: -m 20M -e cycles --overwrite --switch-output -a And the session list: # perf daemon [772262:daemon] base: /opt/perfdata [772338:cycles] perf record -m 20M -e cycles --overwrite --switch-output -a Note the changed '-m 20M' option is in place. Signed-off-by: Jiri Olsa <[email protected]> --- tools/perf/builtin-daemon.c | 100 ++++++++++++++++++++++++++++++++++-- 1 file changed, 97 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c index 15b328f6bd9a..bdddaa2ea388 100644 --- a/tools/perf/builtin-daemon.c +++ b/tools/perf/builtin-daemon.c @@ -12,6 +12,8 @@ #include <stdio.h> #include <unistd.h> #include <errno.h> +#include <sys/inotify.h> +#include <libgen.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/un.h> @@ -75,6 +77,7 @@ struct daemon_session { struct daemon { const char *config; char *config_real; + char *config_base; const char *base_user; char *base; struct list_head sessions; @@ -530,6 +533,7 @@ static void daemon__exit(struct daemon *daemon) daemon_session__remove(session); free(daemon->config_real); + free(daemon->config_base); free(daemon->base); } @@ -566,6 +570,84 @@ static int daemon__reconfig(struct daemon *daemon) return 0; } +static int setup_config_changes(struct daemon *daemon) +{ + char *basen = strdup(daemon->config_real); + char *dirn = strdup(daemon->config_real); + char *base, *dir; + int fd, wd = -1; + + if (!dirn || !basen) + goto out; + + fd = inotify_init1(IN_NONBLOCK|O_CLOEXEC); + if (fd < 0) { + perror("failed: inotify_init"); + goto out; + } + + dir = dirname(dirn); + base = basename(basen); + pr_debug("config file: %s, dir: %s\n", base, dir); + + wd = inotify_add_watch(fd, dir, IN_CLOSE_WRITE); + if (wd >= 0) { + daemon->config_base = strdup(base); + if (!daemon->config_base) { + close(fd); + wd = -1; + } + } else { + perror("failed: inotify_add_watch"); + } + +out: + free(basen); + free(dirn); + return wd < 0 ? -1 : fd; +} + +static bool process_inotify_event(struct daemon *daemon, char *buf, ssize_t len) +{ + char *p = buf; + + while (p < (buf + len)) { + struct inotify_event *event = (struct inotify_event *) p; + + /* + * We monitor config directory, check if our + * config file was changes. + */ + if ((event->mask & IN_CLOSE_WRITE) && + !(event->mask & IN_ISDIR)) { + if (!strcmp(event->name, daemon->config_base)) + return true; + } + p += sizeof(*event) + event->len; + } + return false; +} + +static int handle_config_changes(struct daemon *daemon, int conf_fd, + bool *config_changed) +{ + char buf[4096]; + ssize_t len; + + while (!(*config_changed)) { + len = read(conf_fd, buf, sizeof(buf)); + if (len == -1) { + if (errno != EAGAIN) { + perror("failed: read"); + return -1; + } + return 0; + } + *config_changed = process_inotify_event(daemon, buf, len); + } + return 0; +} + static int setup_config(struct daemon *daemon) { if (daemon->base_user) { @@ -600,8 +682,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], OPT_PARENT(parent_options), OPT_END() }; - int sock_fd = -1; - int sock_pos; + int sock_fd = -1, conf_fd = -1; + int sock_pos, file_pos; struct fdarray fda; int err = 0; @@ -622,16 +704,24 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], pr_info("daemon started (pid %d)\n", getpid()); - fdarray__init(&fda, 1); + fdarray__init(&fda, 2); sock_fd = setup_server_socket(daemon); if (sock_fd < 0) goto out; + conf_fd = setup_config_changes(daemon); + if (conf_fd < 0) + goto out; + sock_pos = fdarray__add(&fda, sock_fd, POLLIN|POLLERR|POLLHUP, 0); if (sock_pos < 0) goto out; + file_pos = fdarray__add(&fda, conf_fd, POLLIN|POLLERR|POLLHUP, 0); + if (file_pos < 0) + goto out; + signal(SIGINT, sig_handler); signal(SIGTERM, sig_handler); @@ -643,6 +733,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], if (fda.entries[sock_pos].revents & POLLIN) err = handle_server_socket(daemon, sock_fd); + if (fda.entries[file_pos].revents & POLLIN) + err = handle_config_changes(daemon, conf_fd, &reconfig); if (reconfig) err = setup_server_config(daemon); @@ -657,6 +749,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], if (sock_fd != -1) close(sock_fd); + if (conf_fd != -1) + close(conf_fd); pr_info("daemon exited\n"); fclose(daemon->out); -- 2.29.2
