From 2a04219dee13ac93d9cc2f8bd6d2a4025cc4e5c2 Mon Sep 17 00:00:00 2001
From: Gerhard Rieger <gerhard@dest-unreach.org>
Date: Thu, 26 Jan 2023 10:06:01 +0100
Subject: [PATCH] Procan: try to find out VSOCK CID only when running as root

---
 CHANGES  | 2 ++
 hostan.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/CHANGES b/CHANGES
index 09231a8..d70478a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -54,6 +54,8 @@ Corrections:
 	restrictive mode. Furthermore Silla Rizzoli experienced that Minicom
 	ignores lock files with mode 600, so it is set to 644 now.
 
+	Procan tries to find out VSOCK CID only when running as root
+
 Features:
 	VSOCK, VSOCK-L support options pf, socktype, prototype (currently
 	useless)
diff --git a/hostan.c b/hostan.c
index dfa1b2e..07212af 100644
--- a/hostan.c
+++ b/hostan.c
@@ -112,11 +112,16 @@ static int iffan(FILE *outfile) {
 static int vsockan(FILE *outfile) {
 	unsigned int cid;
 	int vsock;
+	if (Getuid() != 0) {
+	   return 1;
+	}
 	if ((vsock = Open("/dev/vsock", O_RDONLY, 0)) < 0 ) {
 		Warn1("open(\"/dev/vsock\", ...): %s", strerror(errno));
+		return -1;
 	} else if (Ioctl(vsock, IOCTL_VM_SOCKETS_GET_LOCAL_CID, &cid) < 0) {
 		Warn2("ioctl(%d, IOCTL_VM_SOCKETS_GET_LOCAL_CID, ...): %s",
 		      vsock, strerror(errno));
+		return -1;
 	} else {
 		Notice1("VSOCK CID=%u", cid);
 		fprintf(outfile, "\nVSOCK_CID        = %u\n", cid);