From 00dc4a7a85b32c4337dd3672adec2cbfe3597bfe Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Thu, 25 Mar 2021 12:29:44 +0200
Subject: feat: allow ~/ in config, specification files

---
 src/config.rs  | 12 +++++++++++-
 src/libvirt.rs |  2 +-
 src/spec.rs    | 10 ++++++----
 src/util.rs    | 34 ++++++++++++++++++++++++++++++++++
 vmadm.md       | 12 +++++++++---
 5 files changed, 61 insertions(+), 9 deletions(-)

diff --git a/src/config.rs b/src/config.rs
index 1866971..3f1b341 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,5 +1,6 @@
 //! Tool configuration.
 
+use crate::util::{expand_optional_pathbuf, expand_optional_pathbufs};
 use log::debug;
 use serde::Deserialize;
 use std::default::Default;
@@ -57,11 +58,20 @@ impl Configuration {
             debug!("reading configuration file {}", filename.display());
             let config = fs::read(filename)
                 .map_err(|err| ConfigurationError::ReadError(filename.to_path_buf(), err))?;
-            let config: Configuration = serde_yaml::from_slice(&config)?;
+            let mut config: Configuration = serde_yaml::from_slice(&config)?;
+            config.expand_tildes();
             debug!("config: {:#?}", config);
             Ok(config)
         } else {
             Ok(Self::default())
         }
     }
+
+    fn expand_tildes(&mut self) {
+        expand_optional_pathbuf(&mut self.default_base_image);
+        expand_optional_pathbuf(&mut self.image_directory);
+        expand_optional_pathbuf(&mut self.image_directory);
+        expand_optional_pathbuf(&mut self.ca_key);
+        expand_optional_pathbufs(&mut self.authorized_keys)
+    }
 }
diff --git a/src/libvirt.rs b/src/libvirt.rs
index b144d11..4bf8590 100644
--- a/src/libvirt.rs
+++ b/src/libvirt.rs
@@ -116,7 +116,7 @@ impl Libvirt {
             let disk = find_iso_xml(&xml);
             let flags =
                 VIR_DOMAIN_AFFECT_CONFIG | VIR_DOMAIN_AFFECT_CURRENT | VIR_DOMAIN_AFFECT_LIVE;
-            if disk.is_empty() {
+            if !disk.is_empty() {
                 domain
                     .detach_device_flags(&disk, flags)
                     .map_err(|err| VirtError::DetachIso(name.to_string(), err))?;
diff --git a/src/spec.rs b/src/spec.rs
index a1d1c2f..a00a5e8 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -1,6 +1,7 @@
 //! Virtual machine specification.
 
 use crate::config::Configuration;
+use crate::util::expand_tilde;
 
 use log::debug;
 use serde::{Deserialize, Serialize};
@@ -293,8 +294,8 @@ impl Specification {
             ecdsa_host_cert: input.ecdsa_host_cert.clone(),
             ed25519_host_key: input.ed25519_host_key.clone(),
             ed25519_host_cert: input.ed25519_host_cert.clone(),
-            base: input.base_image(config, name)?,
-            image: input.image(config, name)?,
+            base: expand_tilde(&input.base_image(config, name)?),
+            image: expand_tilde(&input.image(config, name)?),
             image_size_gib: input.image_size_gib(config, name)?,
             memory_mib: input.memory_mib(config, name)?,
             cpus: input.cpus(config, name)?,
@@ -311,8 +312,9 @@ impl Specification {
 fn ssh_keys(filenames: &[PathBuf]) -> Result<Vec<String>, SpecificationError> {
     let mut keys = vec![];
     for filename in filenames {
-        let key = std::fs::read(filename)
-            .map_err(|e| SpecificationError::SshKeyRead(filename.to_path_buf(), e))?;
+        let filename = expand_tilde(filename);
+        let key =
+            std::fs::read(&filename).map_err(|e| SpecificationError::SshKeyRead(filename, e))?;
         let key = String::from_utf8(key)?;
         let key = key.strip_suffix("\n").or(Some(&key)).unwrap();
         keys.push(key.to_string());
diff --git a/src/util.rs b/src/util.rs
index f3e104b..c641ea6 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -2,6 +2,7 @@
 
 use log::debug;
 use std::net::TcpStream;
+use std::path::{Path, PathBuf};
 
 const SSH_PORT: i32 = 22;
 
@@ -15,3 +16,36 @@ pub fn wait_for_ssh(name: &str) {
         }
     }
 }
+
+/// Expand a ~/ at the beginning of a Path to refer to the home directory.
+pub fn expand_tilde(path: &Path) -> PathBuf {
+    if path.starts_with("~/") {
+        if let Some(home) = std::env::var_os("HOME") {
+            let mut expanded = PathBuf::from(home);
+            for comp in path.components().skip(1) {
+                expanded.push(comp);
+            }
+            expanded
+        } else {
+            path.to_path_buf()
+        }
+    } else {
+        path.to_path_buf()
+    }
+}
+
+pub fn expand_optional_pathbuf(maybe_path: &mut Option<PathBuf>) {
+    if let Some(path) = maybe_path {
+        *maybe_path = Some(expand_tilde(path));
+    }
+}
+
+pub fn expand_optional_pathbufs(maybe_paths: &mut Option<Vec<PathBuf>>) {
+    if let Some(paths) = maybe_paths {
+        let mut expanded = vec![];
+        for path in paths {
+            expanded.push(expand_tilde(&path));
+        }
+        *maybe_paths = Some(expanded);
+    }
+}
diff --git a/vmadm.md b/vmadm.md
index 24ffe5c..2d97876 100644
--- a/vmadm.md
+++ b/vmadm.md
@@ -36,9 +36,15 @@ V4cecTlFJGBtUOUAAAAMbGl3QGV4b2xvYmUxAQIDBAUGBw==
 -----END OPENSSH PRIVATE KEY-----
 ~~~
 
+Note that we use *tilde expansion* in filenames to indicate they go
+into the home directory. The Subplot test runner sets the `HOME`
+environment variable to a suitable directory, so that the files don't
+go into the actual home directory of the person running the generated
+test program
+
 ~~~{#config.yaml .file .yaml}
-image_directory: images
-default_base_image: base.qcow2
+image_directory: ~/images
+default_base_image: ~/base.qcow2
 default_image_gib: 5
 default_memory_mib: 2048
 default_cpus: 1
@@ -46,7 +52,7 @@ default_generate_host_certificate: true
 default_autostart: true
 ca_key: ca_key
 authorized_keys:
-  - .ssh/id_rsa.pub
+  - ~/.ssh/id_rsa.pub
 ~~~
 
 ~~~{#ssh_key_pub .file}
-- 
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