From fdd8a22e1df57a8c9254e7d0074301e7dde2c557 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@tuebingen.mpg.de>
Date: Fri, 24 Sep 2021 18:11:06 +0200
Subject: [PATCH] sched: Use integer value for select timeout.

This modifies the public struct sched so that users pass in the
default timeout as an integer value in milliseconds rather than
a struct timeval. This simplifies the code a little and eases the
transition from select(2) to poll(2) because poll(2) also takes a
plain integer for the timeout.

Since para_select() of fd.c now calls ms2tv() to convert the timeout
back to a struct timeval, all executables which link with fd.o must
also link with time.o. This was not the case for para_mixer and
para_audioc, so configure.ac needs to be adjusted accordingly.
---
 afs.c         |  3 +--
 audioc.c      |  2 +-
 audiod.c      |  3 +--
 client.c      |  4 ++--
 configure.ac  |  4 ++--
 fd.c          | 16 +++++++---------
 fd.h          |  3 +--
 filter.c      |  3 +--
 gui.c         |  2 +-
 interactive.c | 14 ++++++++------
 interactive.h |  3 +--
 play.c        |  2 +-
 recv.c        |  3 +--
 sched.c       | 11 ++++++-----
 sched.h       | 10 +++++-----
 server.c      |  6 +++---
 write.c       |  3 +--
 17 files changed, 43 insertions(+), 49 deletions(-)

diff --git a/afs.c b/afs.c
index 71067025..c216b354 100644
--- a/afs.c
+++ b/afs.c
@@ -1003,8 +1003,7 @@ __noreturn void afs_init(int socket_fd)
 	PARA_INFO_LOG("server_socket: %d\n", server_socket);
 	init_admissible_files(OPT_STRING_VAL(AFS_INITIAL_MODE));
 	register_command_task(&s);
-	s.default_timeout.tv_sec = 0;
-	s.default_timeout.tv_usec = 999 * 1000;
+	s.default_timeout = 1000;
 	ret = write(socket_fd, "\0", 1);
 	if (ret != 1) {
 		if (ret == 0)
diff --git a/audioc.c b/audioc.c
index af670633..76b3d6db 100644
--- a/audioc.c
+++ b/audioc.c
@@ -252,7 +252,7 @@ __noreturn static void interactive_session(void)
 	sigaction(SIGINT, &act, NULL);
 	sched.select_function = i9e_select;
 
-	sched.default_timeout.tv_sec = 1;
+	sched.default_timeout = 1000;
 	ret = i9e_open(&ici, &sched);
 	if (ret < 0)
 		goto out;
diff --git a/audiod.c b/audiod.c
index 119adbc0..8e1da6e8 100644
--- a/audiod.c
+++ b/audiod.c
@@ -1510,8 +1510,7 @@ int main(int argc, char *argv[])
 		.context = signal_task,
 	}, &sched);
 
-	sched.default_timeout.tv_sec = 2;
-	sched.default_timeout.tv_usec = 999 * 1000;
+	sched.default_timeout = 2999;
 	ret = schedule(&sched);
 	audiod_cleanup();
 	sched_shutdown(&sched);
diff --git a/client.c b/client.c
index 8caf4483..24f9c61c 100644
--- a/client.c
+++ b/client.c
@@ -123,7 +123,7 @@ fail:
 static int execute_client_command(const char *cmd, char **result)
 {
 	int ret;
-	struct sched command_sched = {.default_timeout = {.tv_sec = 1}};
+	struct sched command_sched = {.default_timeout = 1000};
 	struct exec_task exec_task = {
 		.result_buf = para_strdup(""),
 		.result_size = 1,
@@ -624,7 +624,7 @@ int main(int argc, char *argv[])
 	int ret;
 
 	crypt_init();
-	sched.default_timeout.tv_sec = 1;
+	sched.default_timeout = 1000;
 
 	ret = client_parse_config(argc, argv, &ct, &client_loglevel);
 	if (ret < 0)
diff --git a/configure.ac b/configure.ac
index b817979f..0e37e39e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -586,7 +586,7 @@ fi
 if test $HAVE_OSS = yes -o $HAVE_ALSA = yes; then
 	build_mixer="yes"
 	executables="$executables mixer"
-	mixer_errlist_objs="mixer exec string fd lsu version"
+	mixer_errlist_objs="mixer exec string fd time lsu version"
 	if test $HAVE_OSS = yes; then
 		mixer_errlist_objs="$mixer_errlist_objs oss_mix"
 	fi
@@ -842,6 +842,7 @@ audioc_errlist_objs="
 	lsu
 	net
 	fd
+	time
 	version
 "
 if test $HAVE_READLINE = yes; then
@@ -849,7 +850,6 @@ if test $HAVE_READLINE = yes; then
 		buffer_tree
 		interactive
 		sched
-		time
 	"
 fi
 audioc_objs="$audioc_errlist_objs"
diff --git a/fd.c b/fd.c
index 33891d2e..d72096e1 100644
--- a/fd.c
+++ b/fd.c
@@ -334,8 +334,7 @@ bool file_exists(const char *fn)
  * \param n The highest-numbered descriptor in any of the two sets, plus 1.
  * \param readfds fds that should be checked for readability.
  * \param writefds fds that should be checked for writablility.
- * \param timeout_tv upper bound on the amount of time elapsed before select()
- * returns.
+ * \param timeout Upper bound in milliseconds.
  *
  * \return The return value of the underlying select() call on success, the
  * negative system error code on errors.
@@ -343,12 +342,14 @@ bool file_exists(const char *fn)
  * All arguments are passed verbatim to select(2).
  * \sa select(2) select_tut(2).
  */
-int para_select(int n, fd_set *readfds, fd_set *writefds,
-		struct timeval *timeout_tv)
+int para_select(int n, fd_set *readfds, fd_set *writefds, int timeout)
 {
 	int ret;
+	struct timeval tv;
+
+	ms2tv(timeout, &tv);
 	do
-		ret = select(n, readfds, writefds, NULL, timeout_tv);
+		ret = select(n, readfds, writefds, NULL, &tv);
 	while (ret < 0 && errno == EINTR);
 	if (ret < 0)
 		return -ERRNO_TO_PARA_ERROR(errno);
@@ -653,14 +654,11 @@ int para_munmap(void *start, size_t length)
 
 int write_ok(int fd)
 {
-	struct timeval tv;
 	fd_set wfds;
 
 	FD_ZERO(&wfds);
 	FD_SET(fd, &wfds);
-	tv.tv_sec = 0;
-	tv.tv_usec = 0;
-	return para_select(fd + 1, NULL, &wfds, &tv);
+	return para_select(fd + 1, NULL, &wfds, 0);
 }
 
 /**
diff --git a/fd.h b/fd.h
index c9e79426..820e1cc9 100644
--- a/fd.h
+++ b/fd.h
@@ -6,8 +6,7 @@ int xrename(const char *oldpath, const char *newpath);
 int write_all(int fd, const char *buf, size_t len);
 __printf_2_3 int write_va_buffer(int fd, const char *fmt, ...);
 bool file_exists(const char *);
-int para_select(int n, fd_set *readfds, fd_set *writefds,
-		struct timeval *timeout_tv);
+int para_select(int n, fd_set *readfds, fd_set *writefds, int timeout);
 __must_check int mark_fd_nonblocking(int fd);
 __must_check int mark_fd_blocking(int fd);
 void para_fd_set(int fd, fd_set *fds, int *max_fileno);
diff --git a/filter.c b/filter.c
index d4a24239..95438779 100644
--- a/filter.c
+++ b/filter.c
@@ -149,8 +149,7 @@ int main(int argc, char *argv[])
 		EMBRACE(.name = "stdout", .parent = parent));
 	stdout_task_register(sot, &s);
 
-	s.default_timeout.tv_sec = 1;
-	s.default_timeout.tv_usec = 0;
+	s.default_timeout = 1000;
 	btr_log_tree(sit->btrn, LL_INFO);
 	ret = schedule(&s);
 	sched_shutdown(&s);
diff --git a/gui.c b/gui.c
index d779ff86..7a859a0c 100644
--- a/gui.c
+++ b/gui.c
@@ -1391,7 +1391,7 @@ static int setup_tasks_and_schedule(void)
 	struct status_task status_task = {.fd = -1};
 	struct input_task input_task = {.task = NULL};
 	struct signal_task *signal_task;
-	struct sched sched = {.default_timeout = {.tv_sec = 1}};
+	struct sched sched = {.default_timeout = 1000};
 
 	exec_task.task = task_register(&(struct task_info) {
 		.name = "exec",
diff --git a/interactive.c b/interactive.c
index 041376a1..8e614840 100644
--- a/interactive.c
+++ b/interactive.c
@@ -261,12 +261,11 @@ static void clear_bottom_line(void)
 static bool input_available(void)
 {
 	fd_set rfds;
-	struct timeval tv = {0, 0};
 	int ret;
 
 	FD_ZERO(&rfds);
 	FD_SET(i9ep->ici->fds[0], &rfds);
-	ret = para_select(1, &rfds, NULL, &tv);
+	ret = para_select(1, &rfds, NULL, 0);
 	return ret > 0;
 }
 
@@ -610,17 +609,20 @@ void i9e_signal_dispatch(int sig_num)
  * \param n \sa \ref para_select().
  * \param readfds \sa \ref para_select().
  * \param writefds \sa \ref para_select().
- * \param timeout_tv \sa \ref para_select().
+ * \param timeout \sa \ref para_select().
  *
  * \return \sa \ref para_select().
  *
  * The only difference between this function and \ref para_select() is that
  * \ref i9e_select() returns zero if the select call returned \p EINTR.
  */
-int i9e_select(int n, fd_set *readfds, fd_set *writefds,
-		struct timeval *timeout_tv)
+int i9e_select(int n, fd_set *readfds, fd_set *writefds, int timeout)
 {
-	int ret = select(n, readfds, writefds, NULL, timeout_tv);
+	struct timeval tv;
+	int ret;
+
+	ms2tv(timeout, &tv);
+	ret = select(n, readfds, writefds, NULL, &tv);
 
 	if (ret < 0) {
 		if (errno == EINTR)
diff --git a/interactive.h b/interactive.h
index ddf02d76..4253f79c 100644
--- a/interactive.h
+++ b/interactive.h
@@ -84,8 +84,7 @@ void i9e_print_status_bar(char *buf, unsigned len);
 void i9e_close(void);
 void i9e_signal_dispatch(int sig_num);
 __printf_2_3 void i9e_log(int ll, const char* fmt,...);
-int i9e_select(int n, fd_set *readfds, fd_set *writefds,
-		struct timeval *timeout_tv);
+int i9e_select(int n, fd_set *readfds, fd_set *writefds, int timeout);
 int i9e_extract_completions(const char *word, char **string_list,
 		char ***result);
 char **i9e_complete_commands(const char *word, struct i9e_completer *completers);
diff --git a/play.c b/play.c
index ba9fff70..0c78b960 100644
--- a/play.c
+++ b/play.c
@@ -1255,7 +1255,7 @@ int main(int argc, char *argv[])
 	int ret;
 	unsigned num_inputs;
 
-	sched.default_timeout.tv_sec = 5;
+	sched.default_timeout = 5000;
 	parse_config_or_die(argc, argv);
 	session_open();
 	num_inputs = lls_num_inputs(play_lpr);
diff --git a/recv.c b/recv.c
index 10d55d21..a81eebb8 100644
--- a/recv.c
+++ b/recv.c
@@ -102,8 +102,7 @@ int main(int argc, char *argv[])
 	ti.context = &rn;
 	rn.task = task_register(&ti, &s);
 
-	s.default_timeout.tv_sec = 1;
-	s.default_timeout.tv_usec = 0;
+	s.default_timeout = 1000;
 	ret = schedule(&s);
 	sched_shutdown(&s);
 	r->close(&rn);
diff --git a/sched.c b/sched.c
index aac8efed..8deb7f38 100644
--- a/sched.c
+++ b/sched.c
@@ -137,12 +137,12 @@ int schedule(struct sched *s)
 again:
 	FD_ZERO(&s->rfds);
 	FD_ZERO(&s->wfds);
-	s->select_timeout = s->default_timeout;
+	s->timeout = s->default_timeout;
 	s->max_fileno = -1;
 	clock_get_realtime(&now_struct);
 	sched_preselect(s);
 	ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds,
-		&s->select_timeout);
+		s->timeout);
 	if (ret < 0)
 		return ret;
 	if (ret == 0) {
@@ -370,7 +370,7 @@ void task_notify_all(struct sched *s, int err)
  */
 void sched_min_delay(struct sched *s)
 {
-	s->select_timeout.tv_sec = s->select_timeout.tv_usec = 0;
+	s->timeout = 0;
 }
 
 /**
@@ -387,8 +387,9 @@ void sched_min_delay(struct sched *s)
  */
 void sched_request_timeout(struct timeval *to, struct sched *s)
 {
-	if (tv_diff(&s->select_timeout, to, NULL) > 0)
-		s->select_timeout = *to;
+	long unsigned ms = tv2ms(to);
+	if (s->timeout > ms)
+		s->timeout = ms;
 }
 
 /**
diff --git a/sched.h b/sched.h
index 35e2503e..4695da05 100644
--- a/sched.h
+++ b/sched.h
@@ -13,10 +13,10 @@
  * called after the select call.
  */
 struct sched {
-	/** Initial value before any pre_select call. */
-	struct timeval default_timeout;
-	/** The current timeout for the upcoming select call. */
-	struct timeval select_timeout;
+	/** Initial value (in milliseconds) before any pre_select call. */
+	int default_timeout;
+	/** The timeout (also in milliseconds) for the next select call. */
+	int timeout;
 	/** fds that should be watched for readability. */
 	fd_set rfds;
 	/** fds that should be watched for writability. */
@@ -24,7 +24,7 @@ struct sched {
 	/** Highest numbered file descriptor in any of the above fd sets. */
 	int max_fileno;
 	/** If non-NULL, use this function instead of para_select. */
-	int (*select_function)(int, fd_set *, fd_set *, struct timeval *);
+	int (*select_function)(int, fd_set *, fd_set *, int timeout);
 	/** Tasks which have been registered to the scheduler. */
 	struct list_head task_list;
 };
diff --git a/server.c b/server.c
index e0df714b..729ca1ac 100644
--- a/server.c
+++ b/server.c
@@ -618,13 +618,13 @@ out:
 }
 
 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
-		struct timeval *timeout_tv)
+		int timeout)
 {
 	int ret;
 
 	status_refresh();
 	mutex_unlock(mmd_mutex);
-	ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
+	ret = para_select(max_fileno + 1, readfds, writefds, timeout);
 	mutex_lock(mmd_mutex);
 	return ret;
 }
@@ -658,7 +658,7 @@ int main(int argc, char *argv[])
 	struct server_command_task server_command_task_struct,
 		*sct = &server_command_task_struct;
 
-	sched.default_timeout.tv_sec = 1;
+	sched.default_timeout = 1000;
 	sched.select_function = server_select;
 
 	server_init(argc, argv, sct);
diff --git a/write.c b/write.c
index acfb9460..177b2e66 100644
--- a/write.c
+++ b/write.c
@@ -96,8 +96,7 @@ static int setup_and_schedule(struct lls_parse_result *lpr)
 		wns[i].wid = check_writer_arg_or_die(arg, &wns[i].lpr);
 		register_writer_node(wns + i, cw_btrn, &s);
 	}
-	s.default_timeout.tv_sec = 10;
-	s.default_timeout.tv_usec = 50000;
+	s.default_timeout = 10500;
 	ret = schedule(&s);
 	if (ret >= 0) {
 		int j, ts;
-- 
2.39.2