[src/trunk]: src/lib/librumpuser Implement the writewatchfile routines for a ...

[pooka <pooka%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b770cdf8790d
branches:  trunk
changeset: 781960:b770cdf8790d
user:      pooka <pooka%NetBSD.org@localhost>
date:      Wed Oct 10 11:15:57 2012 +0000

description:
Implement the writewatchfile routines for a Linux hypervisor.  As a
result, the shmif network driver now works when hosted on Linux.

diffstat:

 lib/librumpuser/rumpuser.c |  68 +++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 65 insertions(+), 3 deletions(-)

diffs (96 lines):

diff -r 24bb1fcdc7d3 -r b770cdf8790d lib/librumpuser/rumpuser.c
--- a/lib/librumpuser/rumpuser.c        Wed Oct 10 06:55:25 2012 +0000
+++ b/lib/librumpuser/rumpuser.c        Wed Oct 10 11:15:57 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rumpuser.c,v 1.20 2012/09/14 16:29:22 pooka Exp $      */
+/*     $NetBSD: rumpuser.c,v 1.21 2012/10/10 11:15:57 pooka Exp $      */
 
 /*
  * Copyright (c) 2007-2010 Antti Kantee.  All Rights Reserved.
@@ -28,7 +28,7 @@
 #include "rumpuser_port.h"
 
 #if !defined(lint)
-__RCSID("$NetBSD: rumpuser.c,v 1.20 2012/09/14 16:29:22 pooka Exp $");
+__RCSID("$NetBSD: rumpuser.c,v 1.21 2012/10/10 11:15:57 pooka Exp $");
 #endif /* !lint */
 
 #include <sys/ioctl.h>
@@ -572,7 +572,13 @@
        errno = error;
 }
 
-#ifdef __NetBSD__
+/*
+ * On NetBSD we use kqueue, on Linux we use inotify.  The underlying
+ * interface requirements aren't quite the same, but we have a very
+ * good chance of doing the fd->path mapping on Linux thanks to dcache,
+ * so just keep the existing interfaces for now.
+ */
+#if defined(__NetBSD__)
 int
 rumpuser_writewatchfile_setup(int kq, int fd, intptr_t opaque, int *error)
 {
@@ -615,6 +621,62 @@
                *opaque = kev.udata;
        return rv;
 }
+
+#elif defined(__linux__)
+#include <sys/inotify.h>
+
+int
+rumpuser_writewatchfile_setup(int inotify, int fd, intptr_t notused, int *error)
+{
+       char procbuf[PATH_MAX], linkbuf[PATH_MAX];
+       ssize_t nn;
+
+       if (inotify == -1) {
+               inotify = inotify_init();
+               if (inotify == -1) {
+                       seterror(errno);
+                       return -1;
+               }
+       }
+
+       /* ok, need to map fd into path for inotify */
+       snprintf(procbuf, sizeof(procbuf), "/proc/self/fd/%d", fd);
+       nn = readlink(procbuf, linkbuf, sizeof(linkbuf));
+       if (nn >= (ssize_t)sizeof(linkbuf)) {
+               nn = -1;
+               errno = E2BIG; /* pick something */
+       }
+       if (nn == -1) {
+               seterror(errno);
+               close(inotify);
+               return -1;
+       }
+
+       if (inotify_add_watch(inotify, linkbuf, IN_MODIFY) == -1) {
+               seterror(errno);
+               close(inotify);
+               return -1;
+       }
+
+       return inotify;
+}
+
+int
+rumpuser_writewatchfile_wait(int kq, intptr_t *opaque, int *error)
+{
+       struct inotify_event iev;
+       ssize_t nn;
+
+       do {
+               KLOCK_WRAP(nn = read(kq, &iev, sizeof(iev)));
+       } while (errno == EINTR);
+
+       if (nn == -1) {
+               seterror(errno);
+               return -1;
+       }
+       return (nn/sizeof(iev));
+}
 #endif
 
 /*