proxmox-fetch-answer/src/fetch_plugins/partition.rs

   1 use anyhow::{bail, format_err, Result};
   2 use log::{info, warn};
   3 use std::{
   4     fs::{self, create_dir_all},
   5     path::{Path, PathBuf},
   6     process::Command,
   7 };
   8
   9 static ANSWER_FILE: &str = "answer.toml";
  10 static ANSWER_MP: &str = "/mnt/answer";
  11 // FAT can only handle 11 characters, so shorten Automated Installer Source to AIS
  12 static PARTLABEL: &str = "proxmox-ais";
  13 static SEARCH_PATH: &str = "/dev/disk/by-label";
  14
  15 pub struct FetchFromPartition;
  16
  17 impl FetchFromPartition {
  18     /// Returns the contents of the answer file
  19     pub fn get_answer() -> Result<String> {
  20         info!("Checking for answer file on partition.");
  21
  22         let mut mount_path = PathBuf::from(mount_proxmoxinst_part()?);
  23         mount_path.push(ANSWER_FILE);
  24         let answer = fs::read_to_string(mount_path)
  25             .map_err(|err| format_err!("failed to read answer file - {err}"))?;
  26
  27         info!("Found answer file on partition.");
  28
  29         Ok(answer)
  30     }
  31 }
  32
  33 /// Searches for upper and lower case existence of the partlabel in the search_path
  34 ///
  35 /// # Arguemnts
  36 /// * `partlabel_source` - Partition Label, used as upper and lower case
  37 /// * `search_path` - Path where to search for the partiiton label
  38 fn scan_partlabels(partlabel_source: &str, search_path: &str) -> Result<PathBuf> {
  39     let partlabel = partlabel_source.to_uppercase();
  40     let path = Path::new(search_path).join(&partlabel);
  41     match path.try_exists() {
  42         Ok(true) => {
  43             info!("Found partition with label '{partlabel}'");
  44             return Ok(path);
  45         }
  46         Ok(false) => info!("Did not detect partition with label '{partlabel}'"),
  47         Err(err) => info!("Encountered issue, accessing '{path:?}': {err}"),
  48     }
  49
  50     let partlabel = partlabel_source.to_lowercase();
  51     let path = Path::new(search_path).join(&partlabel);
  52     match path.try_exists() {
  53         Ok(true) => {
  54             info!("Found partition with label '{partlabel}'");
  55             return Ok(path);
  56         }
  57         Ok(false) => info!("Did not detect partition with label '{partlabel}'"),
  58         Err(err) => info!("Encountered issue, accessing '{path:?}': {err}"),
  59     }
  60     bail!("Could not detect upper or lower case labels for '{partlabel_source}'");
  61 }
  62
  63 /// Will search and mount a partition/FS labeled PARTLABEL (proxmox-ais) in lower or uppercase
  64 /// to ANSWER_MP
  65 fn mount_proxmoxinst_part() -> Result<String> {
  66     if let Ok(true) = check_if_mounted(ANSWER_MP) {
  67         info!("Skipping: '{ANSWER_MP}' is already mounted.");
  68         return Ok(ANSWER_MP.into());
  69     }
  70     let part_path = scan_partlabels(PARTLABEL, SEARCH_PATH)?;
  71     info!("Mounting partition at {ANSWER_MP}");
  72     // create dir for mountpoint
  73     create_dir_all(ANSWER_MP)?;
  74     match Command::new("mount")
  75         .args(["-o", "ro"])
  76         .arg(part_path)
  77         .arg(ANSWER_MP)
  78         .output()
  79     {
  80         Ok(output) => {
  81             if output.status.success() {
  82                 Ok(ANSWER_MP.into())
  83             } else {
  84                 warn!("Error mounting: {}", String::from_utf8(output.stderr)?);
  85                 Ok(ANSWER_MP.into())
  86             }
  87         }
  88         Err(err) => bail!("Error mounting: {err}"),
  89     }
  90 }
  91
  92 fn check_if_mounted(target_path: &str) -> Result<bool> {
  93     let mounts = fs::read_to_string("/proc/mounts")?;
  94     for line in mounts.lines() {
  95         if let Some(mp) = line.split(' ').nth(1) {
  96             if mp == target_path {
  97                 return Ok(true);
  98             }
  99         }
 100     }
 101     Ok(false)
 102 }