fs+console: implement poll for system_console

kernel/console/system_console.c

@@ -44,11 +44,17 @@ static int system_console_device_ioctl(file_description* desc, int request,
     return file_description_ioctl(active_console, request, user_argp);
 }
 
+static short system_console_device_poll(file_description* desc, short events) {
+    (void)desc;
+    return file_description_poll(active_console, events);
+}
+
 static struct inode* system_console_device_get(void) {
     static file_ops fops = {
         .read = system_console_device_read,
         .write = system_console_device_write,
         .ioctl = system_console_device_ioctl,
+        .poll = system_console_device_poll,
     };
     static struct inode inode = {
         .fops = &fops, .mode = S_IFCHR, .rdev = makedev(5, 1), .ref_count = 1};

kernel/fs/fs.c

@@ -3,6 +3,7 @@
 #include <kernel/api/dirent.h>
 #include <kernel/api/fcntl.h>
 #include <kernel/api/stdio.h>
+#include <kernel/api/sys/poll.h>
 #include <kernel/lock.h>
 #include <kernel/memory/memory.h>
 #include <kernel/panic.h>
@@ -267,6 +268,19 @@ int file_description_getdents(file_description* desc,
     return inode->fops->getdents(desc, callback, ctx);
 }
 
+NODISCARD short file_description_poll(file_description* desc, short events) {
+    struct inode* inode = desc->inode;
+    if (!inode->fops->poll)
+        return events & (POLLIN | POLLOUT);
+    short revents = inode->fops->poll(desc, events);
+    ASSERT(revents >= 0);
+    if (!(events & POLLIN))
+        ASSERT(!(revents & POLLIN));
+    if (!(events & POLLOUT))
+        ASSERT(!(revents & POLLOUT));
+    return revents;
+}
+
 int file_description_block(file_description* desc,
                            bool (*should_unblock)(file_description*)) {
     if ((desc->flags & O_NONBLOCK) && !should_unblock(desc))

kernel/fs/fs.h

@@ -100,6 +100,7 @@ NODISCARD int file_description_ioctl(file_description*, int request,
                                      void* user_argp);
 NODISCARD int file_description_getdents(file_description*, getdents_callback_fn,
                                         void* ctx);
+NODISCARD short file_description_poll(file_description*, short events);
 
 NODISCARD int file_description_block(file_description*,
                                      bool (*should_unblock)(file_description*));

kernel/syscall/poll.c

@@ -27,18 +27,8 @@ static bool poll_should_unblock(struct poll_blocker* blocker) {
         if (!desc)
             continue;
 
-        file_ops* fops = desc->inode->fops;
         struct pollfd* fd = blocker->fds + i;
-        if (fops->poll) {
-            fd->revents = fops->poll(desc, fd->events);
-            ASSERT(fd->revents >= 0);
-            if (!(fd->events & POLLIN))
-                ASSERT(!(fd->revents & POLLIN));
-            if (!(fd->events & POLLOUT))
-                ASSERT(!(fd->revents & POLLOUT));
-        } else {
-            fd->revents = fd->events & (POLLIN | POLLOUT);
-        }
+        fd->revents = file_description_poll(desc, fd->events);
         if (fd->revents)
             ++blocker->num_events;
     }