Messages in this thread | | | Date | Thu, 10 Dec 2020 19:06:46 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH 2/3] perf tools: Allow to enable/disable events via control file |
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On Thu, Dec 10, 2020 at 05:24:30PM +0100, Jiri Olsa wrote: > On Mon, Dec 07, 2020 at 08:02:20PM +0300, Alexei Budankov wrote: > > Hi, > > > > On 06.12.2020 20:05, Jiri Olsa wrote: > > > Adding new control events to enable/disable specific event. > > > The interface string for control file are: > > > > > > 'enable-<EVENT NAME>' > > > 'disable-<EVENT NAME>' > > > > <SNIP> > > > > > > > > when received the command, perf will scan the current evlist > > > for <EVENT NAME> and if found it's enabled/disabled. > > > > <SNIP> > > > > > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > > > index 70aff26612a9..05723227bebf 100644 > > > --- a/tools/perf/util/evlist.c > > > +++ b/tools/perf/util/evlist.c > > > @@ -1915,7 +1915,13 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd, > > > bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0"); > > > > > > if (bytes_read > 0) { > > > - if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG, > > > + if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_EVSEL_TAG, > > > + (sizeof(EVLIST_CTL_CMD_ENABLE_EVSEL_TAG)-1))) { > > > + *cmd = EVLIST_CTL_CMD_ENABLE_EVSEL; > > > + } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_EVSEL_TAG, > > > + (sizeof(EVLIST_CTL_CMD_DISABLE_EVSEL_TAG)-1))) { > > > + *cmd = EVLIST_CTL_CMD_DISABLE_EVSEL; > > > + } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG, > > > (sizeof(EVLIST_CTL_CMD_ENABLE_TAG)-1))) { > > > *cmd = EVLIST_CTL_CMD_ENABLE; > > > } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG, > > > @@ -1952,6 +1958,8 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd) > > > char cmd_data[EVLIST_CTL_CMD_MAX_LEN]; > > > int ctlfd_pos = evlist->ctl_fd.pos; > > > struct pollfd *entries = evlist->core.pollfd.entries; > > > + struct evsel *evsel; > > > + char *evsel_name; > > > > > > if (!evlist__ctlfd_initialized(evlist) || !entries[ctlfd_pos].revents) > > > return 0; > > > @@ -1967,6 +1975,26 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd) > > > case EVLIST_CTL_CMD_DISABLE: > > > evlist__disable(evlist); > > > break; > > > + case EVLIST_CTL_CMD_ENABLE_EVSEL: > > > + evsel_name = cmd_data + sizeof(EVLIST_CTL_CMD_ENABLE_EVSEL_TAG) - 1; > > > > It makes sense to check that evsel_name still points > > into cmd_data buffer after assigning to event name. > > right, will add that
actualy it's already checked in evlist__ctlfd_recv, evsel_name at worst will be empty string so evlist__find_evsel_by_str will fail
I'll add '' around %s in the error output string:
failed: can't find '%s' event
so it's obvious when it's empty
jirka
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