[libvirt] [PATCHv2 6/7] util: create virvsock.c

[Ján Tomko]

A file for vsock-related helper functions.
virVsockSetGuestCid to set an already-known CID,
virVsockAcquireGuestCid that will use the first available CID

https://bugzilla.redhat.com/show_bug.cgi?id=1291851

Signed-off-by: Ján Tomko <jtomko at redhat.com>
---
 configure.ac             |  8 +++++
 src/libvirt_private.syms |  5 +++
 src/util/Makefile.inc.am |  2 ++
 src/util/virvsock.c      | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virvsock.h      | 29 ++++++++++++++++
 5 files changed, 133 insertions(+)
 create mode 100644 src/util/virvsock.c
 create mode 100644 src/util/virvsock.h

diff --git a/configure.ac b/configure.ac
index cc005ea9e8..b869a17afe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -641,6 +641,14 @@ if test "$with_linux" = "yes"; then
                    [[#include <linux/devlink.h>]])
 fi
 
+dnl
+dnl check for VHOST_VSOCK_SET_GUEST_CID
+dnl
+if test "$with_linux" = "yes"; then
+    AC_CHECK_DECLS([VHOST_VSOCK_SET_GUEST_CID], [], [],
+                   [[#include <linux/vhost.h>]])
+fi
+
 dnl Allow perl/python overrides
 AC_PATH_PROGS([PYTHON], [python3 python2 python])
 if test -z "$PYTHON"; then
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 8e33f3e9f6..0f8045454b 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3121,6 +3121,11 @@ virVHBAManageVport;
 virVHBAPathExists;
 
 
+# util/virvsock.h
+virVsockAcquireGuestCid;
+virVsockSetGuestCid;
+
+
 # util/virxml.h
 virXMLCheckIllegalChars;
 virXMLChildElementCount;
diff --git a/src/util/Makefile.inc.am b/src/util/Makefile.inc.am
index ec8745da7e..a22265606c 100644
--- a/src/util/Makefile.inc.am
+++ b/src/util/Makefile.inc.am
@@ -204,6 +204,8 @@ UTIL_SOURCES = \
 	util/viruuid.h \
 	util/virvhba.c \
 	util/virvhba.h \
+	util/virvsock.c \
+	util/virvsock.h \
 	util/virxdrdefs.h \
 	util/virxml.c \
 	util/virxml.h \
diff --git a/src/util/virvsock.c b/src/util/virvsock.c
new file mode 100644
index 0000000000..8a5c88700b
--- /dev/null
+++ b/src/util/virvsock.c
@@ -0,0 +1,89 @@
+/*
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include <sys/ioctl.h>
+/* #include <fcntl.h> */
+
+#if HAVE_DECL_VHOST_VSOCK_SET_GUEST_CID
+# include <linux/vhost.h>
+#endif
+
+#include "virvsock.h"
+
+#include "virerror.h"
+#include "virlog.h"
+
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+VIR_LOG_INIT("util.vsock");
+
+#if HAVE_DECL_VHOST_VSOCK_SET_GUEST_CID
+static int
+virVsockSetGuestCidQuiet(int fd,
+                         unsigned int guest_cid)
+{
+    uint64_t val = guest_cid;
+
+    return ioctl(fd, VHOST_VSOCK_SET_GUEST_CID, &val);
+}
+
+#else
+static int
+virVsockSetGuestCidQuiet(int fd ATTRIBUTE_UNUSED,
+                         unsigned int guest_cid ATTRIBUTE_UNUSED)
+{
+    errno = ENOSYS;
+    return -1;
+}
+#endif
+
+
+int
+virVsockSetGuestCid(int fd,
+                    unsigned int guest_cid)
+{
+    if (virVsockSetGuestCidQuiet(fd, guest_cid) < 0) {
+        virReportSystemError(errno, "%s",
+                             _("failed to set guest cid"));
+        return -1;
+    }
+
+    return 0;
+}
+
+#define VIR_VSOCK_GUEST_CID_MIN 3
+
+int
+virVsockAcquireGuestCid(int fd,
+                        unsigned int *guest_cid)
+{
+    unsigned int cid = VIR_VSOCK_GUEST_CID_MIN;
+
+    for (; virVsockSetGuestCidQuiet(fd, cid) < 0; cid++) {
+        if (errno != EADDRINUSE) {
+            virReportSystemError(errno, "%s",
+                                 _("failed to acquire guest cid"));
+            return -1;
+        }
+    }
+    *guest_cid = cid;
+
+    return 0;
+}
diff --git a/src/util/virvsock.h b/src/util/virvsock.h
new file mode 100644
index 0000000000..080a322420
--- /dev/null
+++ b/src/util/virvsock.h
@@ -0,0 +1,29 @@
+/*
+ * virvsock.h - vsock related util functions
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __VIR_VSOCK_H__
+# define __VIR_VSOCK_H__
+
+int
+virVsockSetGuestCid(int fd,
+                    unsigned int guest_cid);
+
+int
+virVsockAcquireGuestCid(int fd,
+                        unsigned int *guest_cid);
+#endif /* __VIR_VSOCK_H__ */
-- 
2.16.1