citadel-update: copy image files to tmp directory before updating

citadel-tool/src/update/mod.rs

@@ -3,7 +3,9 @@ use std::path::{Path, PathBuf};
 use libcitadel::{Result, Partition, ResourceImage, ImageHeader, LogLevel, Logger, util};
 use crate::update::kernel::{KernelInstaller, KernelVersion};
 use std::collections::HashSet;
-use std::fs::DirEntry;
+use std::fs::{DirEntry, File};
+use std::io;
+use tempfile::Builder;
 
 mod kernel;
 
@@ -11,6 +13,9 @@ const FLAG_SKIP_SHA: u32 = 0x01;
 const FLAG_NO_PREFER: u32 = 0x02;
 const FLAG_QUIET: u32 = 0x04;
 
+const RESOURCES_DIRECTORY: &str = "/storage/resources";
+const TEMP_DIRECTORY: &str = "/storage/resources/tmp";
+
 pub fn main(args: Vec<String>) {
     let mut args = args.iter().skip(1);
     let mut flags = 0;
@@ -42,14 +47,14 @@ pub fn main(args: Vec<String>) {
 // Search directory containing installed image files for an
 // image file that has an identical shasum and abort the installation
 // if a duplicate is found.
-fn detect_duplicates(image: &ResourceImage) -> Result<()> {
-    let metainfo = image.metainfo();
+fn detect_duplicates(header: &ImageHeader) -> Result<()> {
+    let metainfo = header.metainfo();
     let channel = metainfo.channel();
     let shasum = metainfo.shasum();
 
     validate_channel_name(&channel)?;
 
-    let resource_dir = Path::new("/storage/resources/")
+    let resource_dir = Path::new(RESOURCES_DIRECTORY)
         .join(channel);
 
     if !resource_dir.exists() {
@@ -57,23 +62,52 @@ fn detect_duplicates(image: &ResourceImage) -> Result<()> {
     }
 
     util::read_directory(&resource_dir, |dent| {
-        match ResourceImage::from_path(dent.path()) {
-            Ok(img) => if img.metainfo().shasum() == shasum {
-                bail!("A duplicate image file with the same shasum already exists at {}", img.path().display());
-            },
-            Err(err) =>  warn!("{}", err),
+        if let Ok(hdr) = ImageHeader::from_file(dent.path()) {
+            if hdr.metainfo().shasum() == shasum {
+                bail!("A duplicate image file with the same shasum already exists at {}", dent.path().display());
+            }
         }
         Ok(())
     })
 }
 
-fn install_image(path: &Path, flags: u32) -> Result<()> {
-    if !path.exists() {
-        bail!("file path {} does not exist", path.display());
+fn create_tmp_copy(path: &Path) -> Result<PathBuf> {
+    if !Path::new(TEMP_DIRECTORY).exists() {
+        util::create_dir(TEMP_DIRECTORY)?;
+    }
+    let mut tmpfile = Builder::new()
+        .prefix("update-")
+        .suffix(".img")
+        .tempfile_in(TEMP_DIRECTORY)
+        .map_err(context!("Failed to open temporary file in {}", TEMP_DIRECTORY))?;
+
+    let mut src = File::open(path)
+        .map_err(context!("Failed to open image file {}", path.display()))?;
+
+    info!("Copying image to temporary file {}", tmpfile.path().display());
+    io::copy(&mut src, tmpfile.as_file_mut())
+        .map_err(context!("Failed copying image file to temporary file"))?;
+
+    let (_,path) = tmpfile
+        .keep().map_err(context!("Failed to persist temporary file"))?;
+    Ok(path)
 }
 
-    let mut image = ResourceImage::from_path(path)?;
-    detect_duplicates(&image)?;
+fn install_image(path: &Path, flags: u32) -> Result<()> {
+    if !path.exists() || path.file_name().is_none() {
+        bail!("file path {} does not exist", path.display());
+    }
+    if !util::is_euid_root() {
+        bail!("Image updates must be installed by root user");
+    }
+
+    let header = ImageHeader::from_file(path)?;
+    detect_duplicates(&header)?;
+
+    let tmpfile = create_tmp_copy(path)?;
+
+    let mut image = ResourceImage::from_header(header, tmpfile)?;
+
     prepare_image(&image, flags)?;
 
     match image.metainfo().image_type() {
@@ -277,6 +311,7 @@ fn install_rootfs_image(image: &ResourceImage, flags: u32) -> Result<()> {
 
     image.write_to_partition(&partition)?;
     info!("Image written to {:?}", partition.path());
+    util::remove_file(image.path())?;
     Ok(())
 }
 

libcitadel/src/resource.rs

@@ -1,5 +1,4 @@
 use std::fs::{File,DirEntry};
-use std::ffi::OsStr;
 use std::io::{self, Seek, SeekFrom};
 use std::path::{Path, PathBuf};
 
@@ -73,14 +72,18 @@ impl ResourceImage {
         }
     }
 
-    pub fn from_path<P: AsRef<Path>>(path: P) -> Result<Self> {
-        let header = ImageHeader::from_file(path.as_ref())?;
+    pub fn from_header<P: AsRef<Path>>(header: ImageHeader, path: P) -> Result<Self> {
         if !header.is_magic_valid() {
-            bail!("image file {:?} does not have a valid header", path.as_ref());
+            bail!("image file {} does not have a valid header", path.as_ref().display());
         }
         Ok(Self::new(path.as_ref(), header))
     }
 
+    pub fn from_path<P: AsRef<Path>>(path: P) -> Result<Self> {
+        let header = ImageHeader::from_file(path.as_ref())?;
+        Self::from_header(header, path)
+    }
+
     pub fn is_valid_image(&self) -> bool {
         self.header.is_magic_valid()
     }
@@ -103,8 +106,6 @@ impl ResourceImage {
     }
 
     fn new(path: &Path, header: ImageHeader) -> Self {
-        assert_eq!(path.extension(), Some(OsStr::new("img")), "image filename must have .img extension");
-
         ResourceImage {
             path: path.to_owned(),
             header,
@@ -485,15 +486,19 @@ fn maybe_add_dir_entry(entry: &DirEntry,
                        images: &mut Vec<ResourceImage>) -> Result<()> {
 
     let path = entry.path();
-    if Some(OsStr::new("img")) != path.extension() {
-        return Ok(())
-    }
     let meta = entry.metadata()
         .map_err(context!("failed to read metadata for {:?}", entry.path()))?;
-    if meta.len() < ImageHeader::HEADER_SIZE as u64 {
+    if !meta.is_file() || meta.len() < ImageHeader::HEADER_SIZE as u64 {
         return Ok(())
     }
-    let header = ImageHeader::from_file(&path)?;
+    let header = match ImageHeader::from_file(&path) {
+        Ok(header) => header,
+        Err(err) => {
+            warn!("Unable to read image header from directory entry {}: {}", path.display(), err);
+            return Ok(())
+        }
+    };
+
     if !header.is_magic_valid() {
         return Ok(())
     }