1 files changed, 84 insertions, 0 deletions
diff --git a/src/iopause.c b/src/iopause.c
new file mode 100644
index 0000000..2e24d45
--- /dev/null
+++ b/src/iopause.c
@@ -0,0 +1,84 @@
+#include <poll.h>
+#include "taia.h"
+#include "select.h"
+#include "iopause.h"
+
+/**
+  * @file iopause.c
+  * @author djb
+  * @ref qmail
+  * @brief stateful reading from net
+  * @return > 0 if successful
+  */
+
+int iopause(iopause_fd *x,unsigned int len,struct taia *deadline,struct taia *stamp)
+{
+  struct taia t;
+  int millisecs;
+  double d;
+  int i, r;
+
+  if (taia_less(deadline,stamp))
+    millisecs = 0;
+  else {
+    t = *stamp;
+    taia_sub(&t,deadline,&t);
+    d = taia_approx(&t);
+    if (d > 1000.0) d = 1000.0;
+    millisecs = d * 1000.0 + 20.0;
+    if (millisecs < 0) millisecs = 20.0;
+  }
+
+  for (i = 0; i < len; ++i)
+    x[i].revents = 0;
+
+#ifdef IOPAUSE_POLL
+  r = poll(x,len,millisecs);
+
+  /* XXX: some kernels apparently need x[0] even if len is 0 */
+  /* XXX: how to handle EAGAIN? are kernels really this dumb? */
+  /* XXX: how to handle EINVAL? when exactly can this happen? */
+
+#else
+  struct timeval tv;
+  fd_set rfds;
+  fd_set wfds;
+  int nfds;
+  int fd;
+
+  FD_ZERO(&rfds);
+  FD_ZERO(&wfds);
+
+  nfds = 1;
+  for (i = 0; i < len; ++i) {
+    fd = x[i].fd;
+    if (fd < 0) continue;
+    if (fd >= 8 * sizeof(fd_set)) continue; /*XXX*/
+
+    if (fd >= nfds) nfds = fd + 1;
+    if (x[i].events & IOPAUSE_READ) FD_SET(fd,&rfds);
+    if (x[i].events & IOPAUSE_WRITE) FD_SET(fd,&wfds);
+  }
+
+  tv.tv_sec = millisecs / 1000;
+  tv.tv_usec = 1000 * (millisecs % 1000);
+
+  r = select(nfds,&rfds,&wfds,(fd_set *) 0,&tv);
+  if (r <= 0) return r;
+
+  /* XXX: for EBADF, could seek out and destroy the bad descriptor */
+
+  for (i = 0; i < len; ++i) {
+    fd = x[i].fd;
+    if (fd < 0) continue;
+    if (fd >= 8 * sizeof(fd_set)) continue; /*XXX*/
+
+    if (x[i].events & IOPAUSE_READ)
+      if (FD_ISSET(fd,&rfds)) x[i].revents |= IOPAUSE_READ;
+    if (x[i].events & IOPAUSE_WRITE)
+      if (FD_ISSET(fd,&wfds)) x[i].revents |= IOPAUSE_WRITE;
+  }
+
+#endif
+  return r;
+}