On Tue, Oct 22, 2019 at 09:54:52PM -0400, Igor Lubashev wrote: > Allow perf kvm --stdio to run without access to stdin. > This lets perf kvm to run in a batch mode until interrupted. > > The following now works as expected: > > $ perf kvm top --stdio < /dev/null > > Signed-off-by: Igor Lubashev <[email protected]> > --- > tools/perf/builtin-kvm.c | 33 ++++++++++++++++++++------------- > 1 file changed, 20 insertions(+), 13 deletions(-) > > diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c > index 858da896b518..5217aa3596c7 100644 > --- a/tools/perf/builtin-kvm.c > +++ b/tools/perf/builtin-kvm.c > @@ -930,18 +930,20 @@ static int fd_set_nonblock(int fd) > > static int perf_kvm__handle_stdin(void) > { > - int c; > - > - c = getc(stdin); > - if (c == 'q') > + switch (getc(stdin)) { > + case 'q': > + done = 1; > return 1; > - > - return 0; > + case EOF: > + return 0; > + default: > + return 1; > + } > } > > static int kvm_events_live_report(struct perf_kvm_stat *kvm) > { > - int nr_stdin, ret, err = -EINVAL; > + int nr_stdin = -1, ret, err = -EINVAL; > struct termios save; > > /* live flag must be set first */ > @@ -972,13 +974,16 @@ static int kvm_events_live_report(struct perf_kvm_stat > *kvm) > if (evlist__add_pollfd(kvm->evlist, kvm->timerfd) < 0) > goto out; > > - nr_stdin = evlist__add_pollfd(kvm->evlist, fileno(stdin)); > - if (nr_stdin < 0) > - goto out; > - > if (fd_set_nonblock(fileno(stdin)) != 0) > goto out; > > + /* add stdin, if it is connected */ > + if (getc(stdin) != EOF) { > + nr_stdin = evlist__add_pollfd(kvm->evlist, fileno(stdin)); > + if (nr_stdin < 0) > + goto out; > + } > + > /* everything is good - enable the events and process */ > evlist__enable(kvm->evlist); > > @@ -994,8 +999,10 @@ static int kvm_events_live_report(struct perf_kvm_stat > *kvm) > if (err) > goto out; > > - if (fda->entries[nr_stdin].revents & POLLIN) > - done = perf_kvm__handle_stdin(); > + if (nr_stdin >= 0 && fda->entries[nr_stdin].revents & POLLIN) { > + if (!perf_kvm__handle_stdin())
can this return 0 ? if stdin is EOF then nr_stdin stays -1 > + fda->entries[nr_stdin].events = 0; why do you need to set events to 0 in here? thanks, jirka
