[screen-devel] [PATCH 1/4] Convert select() to poll() in display.c

[Amadeusz Sławiński]

select() limits number of file descriptors that can be used by screen.
Migrate to poll() to avoid this limitation.

Bug: 55697

Signed-off-by: Amadeusz Sławiński <address@hidden>
---
 src/display.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/display.c b/src/display.c
index 3bfa12ad..c4d0f9eb 100644
--- a/src/display.c
+++ b/src/display.c
@@ -33,6 +33,7 @@
 #include <sys/types.h>
 #include <signal.h>
 #include <fcntl.h>
+#include <poll.h>
 #include <sys/ioctl.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -2225,13 +2226,13 @@ void Flush(int progress)
        }
        while (l) {
                if (progress) {
-                       fd_set w;
-                       FD_ZERO(&w);
-                       FD_SET(D_userfd, &w);
-                       struct timeval t;
-                       t.tv_sec = progress;
-                       t.tv_usec = 0;
-                       wr = select(FD_SETSIZE, (fd_set *) 0, &w, (fd_set *) 0, 
&t);
+                       struct pollfd pfd[1];
+
+                       pfd[0].fd = D_userfd;
+                       pfd[0].events = POLLOUT;
+
+                       wr = poll(pfd, ARRAY_SIZE(pfd), progress / 1000);
+
                        if (wr == -1) {
                                if (errno == EINTR)
                                        continue;
@@ -2311,9 +2312,8 @@ void Resize_obuf(void)
 
 void DisplaySleep1000(int n, int eat)
 {
+       struct pollfd pfd[1];
        char buf;
-       fd_set r;
-       struct timeval t;
 
        if (n <= 0)
                return;
@@ -2321,11 +2321,11 @@ void DisplaySleep1000(int n, int eat)
                usleep(1000 * n);
                return;
        }
-       t.tv_usec = (n % 1000) * 1000;
-       t.tv_sec = n / 1000;
-       FD_ZERO(&r);
-       FD_SET(D_userfd, &r);
-       if (select(FD_SETSIZE, &r, (fd_set *) 0, (fd_set *) 0, &t) > 0) {
+
+       pfd[0].fd = D_userfd;
+       pfd[0].events = POLLIN;
+
+       if (poll(pfd, ARRAY_SIZE(pfd), n) > 0) {
                if (eat)
                        read(D_userfd, &buf, 1);
        }
-- 
2.23.0