From 274b0c7bb7f02340b9bf3d645c6ec881ab44dddd Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht@proxmox.com>
Date: Thu, 6 Feb 2020 22:08:07 +0100
Subject: [PATCH] add login banner service

Modeled after the one from PVE, but using rust instead of perl for
resolving the nodename and writing to /etc/issue

Behavior differs a bit. We write all non-loopback addresses to this
file, as the gui accepts connections from them all, so limiting it to
the first one is not really sensible.
Further an error to resolve, or only getting loopback addresses won't
write out an empty /etc/issue file, but a note about the error at the
place where the address would be displayed.

Named it "pbsbanner", not "proxmox-backup-banner" as it's rather an
internal tool anyway and mirrors pvebanner, pmgbanner

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 Makefile                             |  3 +-
 debian/proxmox-backup-server.install |  2 ++
 etc/Makefile                         |  7 ++--
 etc/pbsbanner.service                | 15 +++++++++
 src/bin/pbsbanner.rs                 | 48 ++++++++++++++++++++++++++++
 5 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 etc/pbsbanner.service
 create mode 100644 src/bin/pbsbanner.rs

diff --git a/Makefile b/Makefile
index 537d34f7..1d6a34f9 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,8 @@ USR_BIN := \
 	pxar
 
 # Binaries usable by admins
-USR_SBIN := proxmox-backup-manager
+USR_SBIN := proxmox-backup-manager \
+	pbsbanner
 
 # Binaries for services:
 SERVICE_BIN := \
diff --git a/debian/proxmox-backup-server.install b/debian/proxmox-backup-server.install
index 1db15f42..f5a94f51 100644
--- a/debian/proxmox-backup-server.install
+++ b/debian/proxmox-backup-server.install
@@ -1,8 +1,10 @@
 etc/proxmox-backup-proxy.service /lib/systemd/system/
 etc/proxmox-backup.service /lib/systemd/system/
+etc/pbsbanner.service /lib/systemd/system/
 usr/lib/x86_64-linux-gnu/proxmox-backup/proxmox-backup-api
 usr/lib/x86_64-linux-gnu/proxmox-backup/proxmox-backup-proxy
 usr/sbin/proxmox-backup-manager
+usr/sbin/pbsbanner
 usr/share/javascript/proxmox-backup/css/ext6-pbs.css
 usr/share/javascript/proxmox-backup/images/logo-128.png
 usr/share/javascript/proxmox-backup/images/proxmox_logo.png
diff --git a/etc/Makefile b/etc/Makefile
index da1f083b..93d0c731 100644
--- a/etc/Makefile
+++ b/etc/Makefile
@@ -1,13 +1,16 @@
 include ../defines.mk
 
 UNITS := \
+	pbsbanner.service \
+
+DYNAMIC_UNITS := \
 	proxmox-backup.service \
 	proxmox-backup-proxy.service
 
-all: $(UNITS)
+all: $(UNITS) $(DYNAMIC_UNITS)
 
 clean:
-	rm -f $(UNITS)
+	rm -f $(DYNAMIC_UNITS)
 
 .SUFFIXES: .service.in .service
 .service.in.service:
diff --git a/etc/pbsbanner.service b/etc/pbsbanner.service
new file mode 100644
index 00000000..c2849560
--- /dev/null
+++ b/etc/pbsbanner.service
@@ -0,0 +1,15 @@
+[Unit]
+Description=Proxmox Backup Server Login Banner
+ConditionPathExists=/usr/sbin/pbsbanner
+ConditionPathExists=!/usr/bin/pvebanner
+DefaultDependencies=no
+After=local-fs.target
+Before=console-getty.service
+
+[Service]
+ExecStart=/usr/sbin/pbsbanner
+Type=oneshot
+RemainAfterExit=yes
+
+[Install]
+WantedBy=getty.target
diff --git a/src/bin/pbsbanner.rs b/src/bin/pbsbanner.rs
new file mode 100644
index 00000000..927f68ac
--- /dev/null
+++ b/src/bin/pbsbanner.rs
@@ -0,0 +1,48 @@
+use std::fmt::Write;
+use std::fs;
+use std::net::ToSocketAddrs;
+
+use proxmox::tools;
+
+fn main() {
+    let nodename = tools::nodename();
+    let addr = format!("{}:8007", nodename);
+
+    let mut banner = format!("
+{:-<78}
+
+Welcome to the Proxmox Backup Server. Please use your web browser to
+configure this server - connect to:
+
+",
+        ""
+    );
+
+    if let Ok(saddrs) = addr.to_socket_addrs() {
+        let saddrs: Vec<_> = saddrs
+            .filter_map(|s| match !s.ip().is_loopback() {
+                true => Some(format!(" https://{}/", s)),
+                false => None,
+            })
+            .collect();
+
+        if !saddrs.is_empty() {
+            writeln!(&mut banner, "{}", saddrs.join("\n")).unwrap();
+        } else {
+            writeln!(
+                &mut banner,
+                "hostname '{}' does not resolves to any non-loopback address",
+                nodename
+            )
+            .unwrap();
+        }
+    } else {
+        writeln!(&mut banner, "could not resolve hostname '{}'", nodename).unwrap();
+    }
+
+    // unwrap will never fail for write!:
+    // https://github.com/rust-lang/rust/blob/1.39.0/src/liballoc/string.rs#L2318-L2331
+    write!(&mut banner, "\n{:-<78}\n\n", "").unwrap();
+
+    fs::write("/etc/issue", banner.as_bytes()).expect("Unable to write banner to issue file");
+}
-- 
2.39.5