[pbs-devel] [PATCH proxmox 1/1] fix #4995: compression: Include symlinks in zip file restore

[Filip Schauer <f.schauer@proxmox.com>]

Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
 proxmox-compression/src/zip.rs | 46 ++++++++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 11 deletions(-)

diff --git a/proxmox-compression/src/zip.rs b/proxmox-compression/src/zip.rs
index d2d3fd8..89b079b 100644
--- a/proxmox-compression/src/zip.rs
+++ b/proxmox-compression/src/zip.rs
@@ -204,6 +204,7 @@ pub struct ZipEntry {
     offset: u64,
     is_file: bool,
     is_utf8_filename: bool,
+    symlink_target: Option<OsString>,
 }
 
 impl ZipEntry {
@@ -211,7 +212,13 @@ impl ZipEntry {
     ///
     /// if is_file is false the path will contain an trailing separator,
     /// so that the zip file understands that it is a directory
-    pub fn new<P: AsRef<Path>>(path: P, mtime: i64, mode: u16, is_file: bool) -> Self {
+    pub fn new<P: AsRef<Path>>(
+        path: P,
+        mtime: i64,
+        mode: u16,
+        is_file: bool,
+        symlink_target: Option<&Path>,
+    ) -> Self {
         let mut relpath = PathBuf::new();
 
         for comp in path.as_ref().components() {
@@ -226,6 +233,7 @@ impl ZipEntry {
 
         let filename: OsString = relpath.into();
         let is_utf8_filename = filename.to_str().is_some();
+        let symlink_target_osstr =  symlink_target.map(|x| x.into());
 
         Self {
             filename,
@@ -237,6 +245,7 @@ impl ZipEntry {
             offset: 0,
             is_file,
             is_utf8_filename,
+            symlink_target: symlink_target_osstr,
         }
     }
 
@@ -360,7 +369,9 @@ impl ZipEntry {
                 comment_len: 0,
                 start_disk: 0,
                 internal_flags: 0,
-                external_flags: (self.mode as u32) << 16 | (!self.is_file as u32) << 4,
+                external_flags: (self.mode as u32) << 16
+                    | (self.symlink_target.is_some() as u32) << 5,
+                    | (!self.is_file as u32) << 4
                 offset,
             },
         )
@@ -486,23 +497,30 @@ impl<W: AsyncWrite + Unpin> ZipEncoder<W> {
             .ok_or_else(|| format_err!("had no target during add entry"))?;
         entry.offset = self.byte_count.try_into()?;
         self.byte_count += entry.write_local_header(&mut target).await?;
-        if let Some(content) = content {
-            let mut reader = HashWrapper::new(content);
+
+        if entry.symlink_target.is_some() || content.is_some() {
             let mut enc = DeflateEncoder::with_quality(target, Level::Fastest);
 
-            enc.compress(&mut reader).await?;
+            if let Some(symlink_target) = entry.symlink_target.as_ref() {
+                let cursor = std::io::Cursor::new(symlink_target.as_bytes());
+                let mut reader = HashWrapper::new(cursor);
+                enc.compress(&mut reader).await?;
+                entry.crc32 = reader.finish().0;
+            } else if let Some(content) = content {
+                let mut reader = HashWrapper::new(content);
+                enc.compress(&mut reader).await?;
+                entry.crc32 = reader.finish().0;
+            }
+
             let total_in = enc.total_in();
             let total_out = enc.total_out();
             target = enc.into_inner();
 
-            let (crc32, _reader) = reader.finish();
-
             self.byte_count += total_out as usize;
             entry.compressed_size = total_out;
             entry.uncompressed_size = total_in;
-
-            entry.crc32 = crc32;
         }
+
         self.byte_count += entry.write_data_descriptor(&mut target).await?;
         self.target = Some(target);
 
@@ -658,10 +676,16 @@ where
 
             if entry.file_type().is_file() {
                 let file = tokio::fs::File::open(entry.path()).await?;
-                let ze = ZipEntry::new(entry_path_no_base, mtime, mode, true);
+                let ze = ZipEntry::new(entry_path_no_base, mtime, mode, true, None);
                 Ok(Some((ze, Some(file))))
             } else if entry.file_type().is_dir() {
-                let ze = ZipEntry::new(entry_path_no_base, mtime, mode, false);
+                let ze = ZipEntry::new(entry_path_no_base, mtime, mode, false, None);
+                let content: Option<tokio::fs::File> = None;
+                Ok(Some((ze, content)))
+            } else if entry.file_type().is_symlink() {
+                let target = std::fs::read_link(entry.path())?;
+                let ze =
+                    ZipEntry::new(entry_path_no_base, mtime, mode, true, Some(target.as_ref()));
                 let content: Option<tokio::fs::File> = None;
                 Ok(Some((ze, content)))
             } else {
-- 
2.39.2