[pve-devel] [PATCH v1 installer 14/18] auto-installer: add fetch answer binary

[Aaron Lauterer <a.lauterer@proxmox.com>]

it is supposed to be run first and fetch an answer file.

The initial implementation searches for a partition/filesystem called
'proxmoxinst' or 'PROXMOXINST' with an 'answer.toml' file in the root
directory.

Once it has an answer file, it will call the 'proxmox-auto-installer'
and pipe in the contents via stdin.

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---
 Makefile                                      |   1 +
 .../src/bin/proxmox-fetch-answer.rs           |  73 +++++++++++++
 .../src/fetch_plugins/mod.rs                  |   1 +
 .../src/fetch_plugins/partition.rs            | 102 ++++++++++++++++++
 proxmox-auto-installer/src/lib.rs             |   1 +
 5 files changed, 178 insertions(+)
 create mode 100644 proxmox-auto-installer/src/bin/proxmox-fetch-answer.rs
 create mode 100644 proxmox-auto-installer/src/fetch_plugins/mod.rs
 create mode 100644 proxmox-auto-installer/src/fetch_plugins/partition.rs

diff --git a/Makefile b/Makefile
index 9c933d9..b724789 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,7 @@ PREFIX = /usr
 BINDIR = $(PREFIX)/bin
 USR_BIN := \
 	   proxmox-tui-installer\
+	   proxmox-fetch-answer\
 	   proxmox-auto-installer
 
 COMPILED_BINS := \
diff --git a/proxmox-auto-installer/src/bin/proxmox-fetch-answer.rs b/proxmox-auto-installer/src/bin/proxmox-fetch-answer.rs
new file mode 100644
index 0000000..baf2bd2
--- /dev/null
+++ b/proxmox-auto-installer/src/bin/proxmox-fetch-answer.rs
@@ -0,0 +1,73 @@
+use anyhow::{anyhow, bail, Result};
+use log::{error, info, LevelFilter};
+use proxmox_auto_installer::fetch_plugins::partition::FetchFromPartition;
+use proxmox_auto_installer::log::AutoInstLogger;
+use std::io::Write;
+use std::process::{Command, ExitCode, Stdio};
+
+static LOGGER: AutoInstLogger = AutoInstLogger;
+
+pub fn init_log() -> Result<()> {
+    AutoInstLogger::init("/tmp/fetch_answer.log")?;
+    log::set_logger(&LOGGER)
+        .map(|()| log::set_max_level(LevelFilter::Info))
+        .map_err(|err| anyhow!(err))
+}
+
+fn fetch_answer() -> Result<String> {
+    info!("Checking for partition");
+    match FetchFromPartition::get_answer() {
+        Ok(answer) => return Ok(answer),
+        Err(err) => info!("Fetching answer file from partition failed: {}", err),
+    }
+    // TODO: add more options to get an answer file, e.g. download from url where url could be
+    // fetched via txt records on predefined subdomain, kernel param, dhcp option, ...
+
+    bail!("Could not find any answer file!")
+}
+
+fn main() -> ExitCode {
+    if let Err(err) = init_log() {
+        panic!("could not initilize logging: {err}");
+    }
+
+    info!("Fetching answer file");
+    let answer = match fetch_answer() {
+        Ok(answer) => answer,
+        Err(err) => {
+            error!("Aborting: {}", err);
+            return ExitCode::FAILURE;
+        }
+    };
+
+    let mut child = match Command::new("/usr/bin/proxmox-auto-installer")
+        .stdout(Stdio::inherit())
+        .stdin(Stdio::piped())
+        .stderr(Stdio::null())
+        .spawn()
+    {
+        Ok(child) => child,
+        Err(err) => panic!("Failed to start automatic installation: {}", err),
+    };
+
+    let mut stdin = child.stdin.take().expect("Failed to open stdin");
+    std::thread::spawn(move || {
+        stdin
+            .write_all(answer.as_bytes())
+            .expect("Failed to write to stdin");
+    });
+
+    match child.wait() {
+        Ok(status) => {
+            if status.success() {
+                ExitCode::SUCCESS
+            } else {
+                ExitCode::FAILURE // Will be trapped
+            }
+        }
+        Err(err) => {
+            error!("Auto installer exited: {err}");
+            ExitCode::FAILURE
+        }
+    }
+}
diff --git a/proxmox-auto-installer/src/fetch_plugins/mod.rs b/proxmox-auto-installer/src/fetch_plugins/mod.rs
new file mode 100644
index 0000000..44399e6
--- /dev/null
+++ b/proxmox-auto-installer/src/fetch_plugins/mod.rs
@@ -0,0 +1 @@
+pub mod partition;
diff --git a/proxmox-auto-installer/src/fetch_plugins/partition.rs b/proxmox-auto-installer/src/fetch_plugins/partition.rs
new file mode 100644
index 0000000..0552ddd
--- /dev/null
+++ b/proxmox-auto-installer/src/fetch_plugins/partition.rs
@@ -0,0 +1,102 @@
+use anyhow::{bail, Result};
+use log::{info, warn};
+use std::fs::read_to_string;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+static ANSWER_FILE: &str = "answer.toml";
+static ANSWER_MP: &str = "/mnt/answer";
+static PARTLABEL: &str = "proxmoxinst";
+static SEARCH_PATH: &str = "/dev/disk/by-label";
+
+pub struct FetchFromPartition;
+
+impl FetchFromPartition {
+    /// Returns the contents of the answer file
+    pub fn get_answer() -> Result<String> {
+        let part_path = Self::scan_partlabels()?;
+        Self::mount_part(part_path)?;
+        Self::get_answer_file()
+    }
+
+    /// Searches for upper and lower case existence of the PARTLABEL in the SEARCH_PATH
+    fn scan_partlabels() -> Result<PathBuf> {
+        let partlabel = PARTLABEL.to_uppercase();
+        let path = Path::new(SEARCH_PATH).join(partlabel.clone());
+        match path.try_exists() {
+            Ok(true) => {
+                info!("Found partition with label '{}'", partlabel);
+                return Ok(path);
+            }
+            Ok(false) => info!("Did not detect partition with label '{}'", partlabel),
+            Err(err) => info!("Encountered issue, accessing '{}': {}", path.display(), err),
+        }
+
+        let partlabel = PARTLABEL.to_lowercase();
+        let path = Path::new(SEARCH_PATH).join(partlabel.clone());
+        match path.try_exists() {
+            Ok(true) => {
+                info!("Found partition with label '{}'", partlabel);
+                return Ok(path);
+            }
+            Ok(false) => info!("Did not detect partition with label '{}'", partlabel),
+            Err(err) => info!("Encountered issue, accessing '{}': {}", path.display(), err),
+        }
+        bail!(
+            "Could not detect upper or lower case labels for '{}'",
+            PARTLABEL
+        );
+    }
+
+    /// Will mount source path to ANSWER_MP
+    ///
+    /// # Arguments
+    ///
+    /// * `source` - `PathBuf` of the source location
+    fn mount_part(source: PathBuf) -> Result<()> {
+        info!("Mounting partition at {ANSWER_MP}");
+        // create dir for mountpoint
+        match Command::new("/usr/bin/mkdir")
+            .arg(ANSWER_MP)
+            .arg("-p")
+            .output()
+        {
+            Ok(output) => {
+                if !output.status.success() {
+                    warn!(
+                        "Error creating mount path: {}",
+                        String::from_utf8(output.stderr)?
+                    )
+                }
+            }
+            Err(err) => bail!("Error creating mount path: {}", err),
+        }
+        match Command::new("/usr/bin/mount")
+            .arg(source)
+            .arg(ANSWER_MP)
+            .output()
+        {
+            Ok(output) => {
+                if output.status.success() {
+                    Ok(())
+                } else {
+                    warn!("Error mounting: {}", String::from_utf8(output.stderr)?);
+                    Ok(())
+                }
+            }
+            Err(err) => bail!("Error mounting: {}", err),
+        }
+    }
+
+    /// Searches for answer file and returns contents if found
+    fn get_answer_file() -> Result<String> {
+        let answer_path = Path::new(ANSWER_MP).join(ANSWER_FILE);
+        match answer_path.try_exists() {
+            Ok(true) => Ok(read_to_string(answer_path)?),
+            _ => bail!(
+                "could not find answer file expected at: {}",
+                answer_path.display()
+            ),
+        }
+    }
+}
diff --git a/proxmox-auto-installer/src/lib.rs b/proxmox-auto-installer/src/lib.rs
index 6636cc7..0a153b2 100644
--- a/proxmox-auto-installer/src/lib.rs
+++ b/proxmox-auto-installer/src/lib.rs
@@ -1,4 +1,5 @@
 pub mod answer;
+pub mod fetch_plugins;
 pub mod log;
 pub mod udevinfo;
 pub mod utils;
-- 
2.39.2