1 files changed, 54 insertions, 0 deletions
diff --git a/kernel/poll.c b/kernel/poll.c
new file mode 100644
index 0000000..5e02723
--- /dev/null
+++ b/kernel/poll.c
@@ -0,0 +1,54 @@
+#include <fs/vfs.h>
+#include <halts.h>
+#include <poll.h>
+#include <sched/scheduler.h>
+
+int poll(struct pollfd *fds, size_t nfds, int timeout) {
+  (void)timeout;
+  int read_locks[nfds];
+  int write_locks[nfds];
+  int disconnect_locks[nfds];
+  for (size_t i = 0; i < nfds; i++) {
+    if (fds[i].fd < 0)
+      continue;
+    vfs_fd_t *f = get_vfs_fd(fds[i].fd);
+    if (fds[i].events & POLLIN)
+      read_locks[i] = create_read_fdhalt(f);
+    if (fds[i].events & POLLOUT)
+      write_locks[i] = create_write_fdhalt(f);
+    if (fds[i].events & POLLHUP)
+      disconnect_locks[i] = create_disconnect_fdhalt(f);
+  }
+
+  switch_task();
+
+  for (size_t i = 0; i < nfds; i++) {
+    if (fds[i].fd < 0)
+      continue;
+    if (fds[i].events & POLLIN)
+      unset_read_fdhalt(read_locks[i]);
+    if (fds[i].events & POLLOUT)
+      unset_write_fdhalt(write_locks[i]);
+    if (fds[i].events & POLLHUP)
+      unset_disconnect_fdhalt(disconnect_locks[i]);
+  }
+  for (size_t i = 0; i < nfds; i++) {
+    if (0 > fds[i].fd) {
+      fds[i].revents = 0;
+      continue;
+    }
+    vfs_fd_t *f = get_vfs_fd(fds[i].fd);
+    if (!f) {
+      if (fds[i].events & POLLHUP)
+        fds[i].revents |= POLLHUP;
+    } else {
+      if (f->inode->has_data && fds[i].events & POLLIN)
+        fds[i].revents |= POLLIN;
+      if (f->inode->can_write && fds[i].events & POLLOUT)
+        fds[i].revents |= POLLOUT;
+      if (!(f->inode->is_open) && fds[i].events & POLLHUP)
+        fds[i].revents |= POLLHUP;
+    }
+  }
+  return 0;
+}