From 9fe6619d4a95c4a5fadf7b41548c5cf85eebd915 Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Fri, 19 Jan 2018 13:48:10 +0000
Subject: [PATCH] util: add virGetUNIXSocketPath helper

When receiving multiple socket FDs from systemd, it is critical to know
what socket address each corresponds to so we can setup the right
protocols on each.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 src/libvirt_private.syms |  1 +
 src/util/virutil.c       | 45 ++++++++++++++++++++++++++++++++++++++++
 src/util/virutil.h       |  1 +
 3 files changed, 47 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 9339c2c325..7404759f7f 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2980,6 +2980,7 @@ virGetListenFDs;
 virGetSelfLastChanged;
 virGetSystemPageSize;
 virGetSystemPageSizeKB;
+virGetUNIXSocketPath;
 virGetUnprivSGIOSysfsPath;
 virGetUserCacheDirectory;
 virGetUserConfigDirectory;
diff --git a/src/util/virutil.c b/src/util/virutil.c
index e9dbaf3d7a..8352e0f1f1 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -68,6 +68,10 @@
 # include <shlobj.h>
 #endif
 
+#ifdef HAVE_SYS_UN_H
+# include <sys/un.h>
+#endif
+
 #include "c-ctype.h"
 #include "mgetgroups.h"
 #include "virerror.h"
@@ -1978,6 +1982,47 @@ virGetListenFDs(void)
 
 #endif /* WIN32 */
 
+#ifdef HAVE_SYS_UN_H
+char *virGetUNIXSocketPath(int fd)
+{
+    struct sockaddr_storage ss = { 0 };
+    struct sockaddr_un *un = (struct sockaddr_un *)&ss;
+    socklen_t len = sizeof(ss);
+    char *path;
+
+    if (getsockname(fd, (struct sockaddr *)&ss, &len) < 0) {
+        virReportSystemError(errno, _("Unable to get address of FD %d"), fd);
+        return NULL;
+    }
+
+    if (ss.ss_family != AF_UNIX) {
+        virReportSystemError(EINVAL, _("FD %d is not a UNIX socket, has af=%d"),
+                             fd, ss.ss_family);
+        return NULL;
+    }
+
+    if (un->sun_path[0] == '\0')
+        un->sun_path[0] = '@';
+
+    if (VIR_ALLOC_N(path, sizeof(un->sun_path) + 1) < 0)
+        return NULL;
+
+    memcpy(path, un->sun_path, sizeof(un->sun_path));
+    path[sizeof(un->sun_path)] = '\0';
+    return path;
+}
+
+#else /* HAVE_SYS_UN_H */
+
+char *virGetUNIXSocketPath(int fd)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("UNIX sockets not supported on this platform");
+    return NULL;
+}
+
+#endif /* HAVE_SYS_UN_H */
+
 #ifndef WIN32
 long virGetSystemPageSize(void)
 {
diff --git a/src/util/virutil.h b/src/util/virutil.h
index 9381ad5682..be0f6b0ea8 100644
--- a/src/util/virutil.h
+++ b/src/util/virutil.h
@@ -207,6 +207,7 @@ verify((int)VIR_TRISTATE_BOOL_NO == (int)VIR_TRISTATE_SWITCH_OFF);
 verify((int)VIR_TRISTATE_BOOL_ABSENT == (int)VIR_TRISTATE_SWITCH_ABSENT);
 
 unsigned int virGetListenFDs(void);
+char *virGetUNIXSocketPath(int fd);
 
 long virGetSystemPageSize(void) ATTRIBUTE_NOINLINE;
 long virGetSystemPageSizeKB(void) ATTRIBUTE_NOINLINE;
-- 
2.47.2