Messages in this thread | | | Date | Wed, 3 Feb 2021 18:13:59 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 07/24] perf daemon: Add config file change check |
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Em Sun, Jan 31, 2021 at 12:48:39AM +0100, Jiri Olsa escreveu: > Adding support to detect daemon's config file changes > and re-read the configuration when that happens. > > Using inotify file descriptor pluged 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 <jolsa@kernel.org> > --- > tools/perf/builtin-daemon.c | 99 +++++++++++++++++++++++++++++++++++-- > 1 file changed, 96 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c > index be2ade9967b3..d0a0a998e073 100644 > --- a/tools/perf/builtin-daemon.c > +++ b/tools/perf/builtin-daemon.c > @@ -10,6 +10,8 @@ > #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> > @@ -73,6 +75,7 @@ struct session { > struct daemon { > const char *config; > char *config_real; > + char *config_base; > const char *base_user; > char *base; > struct list_head sessions; > @@ -493,6 +496,7 @@ static void daemon__free(struct daemon *daemon) > session__remove(session); > > free(daemon->config_real); > + free(daemon->config_base); > free(daemon->base);
Please replace those with zfree()
> } > > @@ -535,6 +539,83 @@ 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; > + > + if (!dirn || !basen) > + return -ENOMEM;
This may leak one of them
> + > + fd = inotify_init1(IN_NONBLOCK|O_CLOEXEC); > + if (fd < 0) { > + perror("failed: inotify_init"); > + return -1; > + }
Cool that inotify is being used here :-)
> + > + 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"); > + } > + > + 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) { > @@ -569,8 +650,8 @@ 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; > > @@ -591,16 +672,24 @@ 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); > > @@ -612,6 +701,8 @@ 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); > @@ -625,6 +716,8 @@ 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 >
--
- Arnaldo
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