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

   1 use anyhow::{format_err, Error, 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 static PARTLABEL: &str = "proxmox-inst-src";
  12 static SEARCH_PATH: &str = "/dev/disk/by-label";
  13
  14 pub struct FetchFromPartition;
  15
  16 impl FetchFromPartition {
  17     /// Returns the contents of the answer file
  18     pub fn get_answer() -> Result<String> {
  19         info!("Checking for answer file on partition.");
  20
  21         let mut mount_path = PathBuf::from(mount_proxmoxinst_part()?);
  22         mount_path.push(ANSWER_FILE);
  23         let answer = fs::read_to_string(mount_path)
  24             .map_err(|err| format_err!("failed to read answer file - {err}"))?;
  25
  26         info!("Found answer file on partition.");
  27
  28         Ok(answer)
  29     }
  30 }
  31
  32 /// Searches for upper and lower case existence of the partlabel in the search_path
  33 ///
  34 /// # Arguemnts
  35 /// * `partlabel_source` - Partition Label, used as upper and lower case
  36 /// * `search_path` - Path where to search for the partiiton label
  37 fn scan_partlabels(partlabel_source: &str, search_path: &str) -> Result<PathBuf> {
  38     let partlabel = partlabel_source.to_uppercase();
  39     let path = Path::new(search_path).join(&partlabel);
  40     match path.try_exists() {
  41         Ok(true) => {
  42             info!("Found partition with label '{partlabel}'");
  43             return Ok(path);
  44         }
  45         Ok(false) => info!("Did not detect partition with label '{partlabel}'"),
  46         Err(err) => info!("Encountered issue, accessing '{path:?}': {err}"),
  47     }
  48
  49     let partlabel = partlabel_source.to_lowercase();
  50     let path = Path::new(search_path).join(&partlabel);
  51     match path.try_exists() {
  52         Ok(true) => {
  53             info!("Found partition with label '{partlabel}'");
  54             return Ok(path);
  55         }
  56         Ok(false) => info!("Did not detect partition with label '{partlabel}'"),
  57         Err(err) => info!("Encountered issue, accessing '{path:?}': {err}"),
  58     }
  59     Err(Error::msg(format!(
  60         "Could not detect upper or lower case labels for '{partlabel_source}'"
  61     )))
  62 }
  63
  64 /// Will search and mount a partition/FS labeled PARTLABEL (proxmox-inst-src) in lower or uppercase
  65 /// to ANSWER_MP
  66 fn mount_proxmoxinst_part() -> Result<String> {
  67     if let Ok(true) = check_if_mounted(ANSWER_MP) {
  68         info!("Skipping: '{ANSWER_MP}' is already mounted.");
  69         return Ok(ANSWER_MP.into());
  70     }
  71     let part_path = scan_partlabels(PARTLABEL, SEARCH_PATH)?;
  72     info!("Mounting partition at {ANSWER_MP}");
  73     // create dir for mountpoint
  74     create_dir_all(ANSWER_MP)?;
  75     match Command::new("mount")
  76         .args(["-o", "ro"])
  77         .arg(part_path)
  78         .arg(ANSWER_MP)
  79         .output()
  80     {
  81         Ok(output) => {
  82             if output.status.success() {
  83                 Ok(ANSWER_MP.into())
  84             } else {
  85                 warn!("Error mounting: {}", String::from_utf8(output.stderr)?);
  86                 Ok(ANSWER_MP.into())
  87             }
  88         }
  89         Err(err) => Err(Error::msg(format!("Error mounting: {err}"))),
  90     }
  91 }
  92
  93 fn check_if_mounted(target_path: &str) -> Result<bool> {
  94     let mounts = fs::read_to_string("/proc/mounts")?;
  95     for line in mounts.lines() {
  96         if let Some(mp) = line.split(' ').nth(1) {
  97             if mp == target_path {
  98                 return Ok(true);
  99             }
 100         }
 101     }
 102     Ok(false)
 103 }