[pbs-devel] [PATCH v2 proxmox-backup/pve-container 0/5] improve error handling of pxar extractor

[pbs-devel] [PATCH v2 proxmox-backup/pve-container 0/5] improve error handling of pxar extractor

[Max Carrara]

This v2 incorporates the feedback given on v1 (thanks btw!).

v1 of this series can be found here:
https://lists.proxmox.com/pipermail/pbs-devel/2023-June/006161.html

Max Carrara (4):
  pbs-client: pxar: preserve error context
  pbs-client: pxar: refactor body of `extract_archive` to
    `ExtractorIter`
  pbs-client: pxar: add PxarExtractContext
  proxmox-backup-client: restore: add 'ignore-extract-device-errors'
    flag

 pbs-client/src/pxar/create.rs     |  22 +-
 pbs-client/src/pxar/dir_stack.rs  |   8 +-
 pbs-client/src/pxar/extract.rs    | 542 +++++++++++++++++++++---------
 pbs-client/src/pxar/metadata.rs   |  44 +--
 pbs-client/src/pxar/mod.rs        |   2 +-
 pbs-client/src/pxar/tools.rs      |  11 +-
 proxmox-backup-client/src/main.rs |  32 +-
 7 files changed, 445 insertions(+), 216 deletions(-)


pve-container:

Max Carrara (1):
  fix #3460: restore: honor '--ignore-unpack-errors' flag for pbs

 src/PVE/LXC/Create.pm | 4 ++++
 1 file changed, 4 insertions(+)

-- 
2.39.2

[pbs-devel] [PATCH v2 proxmox-backup 1/5] pbs-client: pxar: preserve error context

[Max Carrara]

In order to preserve the source(s) of errors, `anyhow::Context` is
used instead of propagating errors via `Result::map_err()` and / or
`anyhow::format_err!()`.

This makes it possible to access e.g. an underlying `io::Error` or
`nix::Errno` etc. that caused an execution path to fail.

Certain usages of `anyhow::bail!()` are also changed / replaced
in order to preserve context.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---
 Changes v1 --> v2:
  * Replace instances of `.context(format!(...))` with
    `.with_context(|| format!(...))` where applicable to avoid unnecessarily
    calling `format!()`

 pbs-client/src/pxar/create.rs    |  22 ++---
 pbs-client/src/pxar/dir_stack.rs |   8 +-
 pbs-client/src/pxar/extract.rs   | 141 ++++++++++++++-----------------
 pbs-client/src/pxar/metadata.rs  |  44 ++++------
 pbs-client/src/pxar/tools.rs     |  11 ++-
 5 files changed, 102 insertions(+), 124 deletions(-)

diff --git a/pbs-client/src/pxar/create.rs b/pbs-client/src/pxar/create.rs
index a9a956c2..2577cf98 100644
--- a/pbs-client/src/pxar/create.rs
+++ b/pbs-client/src/pxar/create.rs
@@ -7,7 +7,7 @@ use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 
-use anyhow::{bail, format_err, Error};
+use anyhow::{bail, Context, Error};
 use futures::future::BoxFuture;
 use futures::FutureExt;
 use nix::dir::Dir;
@@ -159,7 +159,7 @@ where
         fs_magic,
         &mut fs_feature_flags,
     )
-    .map_err(|err| format_err!("failed to get metadata for source directory: {}", err))?;
+    .context("failed to get metadata for source directory")?;
 
     let mut device_set = options.device_set.clone();
     if let Some(ref mut set) = device_set {
@@ -441,7 +441,7 @@ impl Archiver {
             ) {
                 Ok(stat) => stat,
                 Err(ref err) if err.not_found() => continue,
-                Err(err) => bail!("stat failed on {:?}: {}", full_path, err),
+                Err(err) => return Err(err).context(format!("stat failed on {:?}", full_path)),
             };
 
             let match_path = PathBuf::from("/").join(full_path.clone());
@@ -796,7 +796,7 @@ fn get_fcaps(
             Ok(())
         }
         Err(Errno::EBADF) => Ok(()), // symlinks
-        Err(err) => bail!("failed to read file capabilities: {}", err),
+        Err(err) => Err(err).context("failed to read file capabilities"),
     }
 }
 
@@ -818,7 +818,7 @@ fn get_xattr_fcaps_acl(
             return Ok(());
         }
         Err(Errno::EBADF) => return Ok(()), // symlinks
-        Err(err) => bail!("failed to read xattrs: {}", err),
+        Err(err) => return Err(err).context("failed to read xattrs"),
     };
 
     for attr in &xattrs {
@@ -843,7 +843,9 @@ fn get_xattr_fcaps_acl(
             Err(Errno::ENODATA) => (), // it got removed while we were iterating...
             Err(Errno::EOPNOTSUPP) => (), // shouldn't be possible so just ignore this
             Err(Errno::EBADF) => (),   // symlinks, shouldn't be able to reach this either
-            Err(err) => bail!("error reading extended attribute {:?}: {}", attr, err),
+            Err(err) => {
+                return Err(err).context(format!("error reading extended attribute {attr:?}"))
+            }
         }
     }
 
@@ -858,7 +860,7 @@ fn get_chattr(metadata: &mut Metadata, fd: RawFd) -> Result<(), Error> {
         Err(errno) if errno_is_unsupported(errno) => {
             return Ok(());
         }
-        Err(err) => bail!("failed to read file attributes: {}", err),
+        Err(err) => return Err(err).context("failed to read file attributes"),
     }
 
     metadata.stat.flags |= Flags::from_chattr(attr).bits();
@@ -880,7 +882,7 @@ fn get_fat_attr(metadata: &mut Metadata, fd: RawFd, fs_magic: i64) -> Result<(),
         Err(errno) if errno_is_unsupported(errno) => {
             return Ok(());
         }
-        Err(err) => bail!("failed to read fat attributes: {}", err),
+        Err(err) => return Err(err).context("failed to read fat attributes"),
     }
 
     metadata.stat.flags |= Flags::from_fat_attr(attr).bits();
@@ -919,7 +921,7 @@ fn get_quota_project_id(
         if errno_is_unsupported(errno) {
             return Ok(());
         } else {
-            bail!("error while reading quota project id ({})", errno);
+            return Err(errno).context("error while reading quota project id");
         }
     }
 
@@ -973,7 +975,7 @@ fn get_acl_do(
         Err(Errno::EBADF) => return Ok(()),
         // Don't bail if there is no data
         Err(Errno::ENODATA) => return Ok(()),
-        Err(err) => bail!("error while reading ACL - {}", err),
+        Err(err) => return Err(err).context("error while reading ACL"),
     };
 
     process_acl(metadata, acl, acl_type)
diff --git a/pbs-client/src/pxar/dir_stack.rs b/pbs-client/src/pxar/dir_stack.rs
index 0cc4e6a5..43cbee1d 100644
--- a/pbs-client/src/pxar/dir_stack.rs
+++ b/pbs-client/src/pxar/dir_stack.rs
@@ -2,7 +2,7 @@ use std::ffi::OsString;
 use std::os::unix::io::{AsRawFd, BorrowedFd, RawFd};
 use std::path::{Path, PathBuf};
 
-use anyhow::{bail, format_err, Error};
+use anyhow::{bail, Context, Error};
 use nix::dir::Dir;
 use nix::fcntl::OFlag;
 use nix::sys::stat::{mkdirat, Mode};
@@ -130,7 +130,7 @@ impl PxarDirStack {
         let dirs_len = self.dirs.len();
         let mut fd = self.dirs[self.created - 1]
             .try_as_borrowed_fd()
-            .ok_or_else(|| format_err!("lost track of directory file descriptors"))?
+            .context("lost track of directory file descriptors")?
             .as_raw_fd();
 
         while self.created < dirs_len {
@@ -142,7 +142,7 @@ impl PxarDirStack {
 
         self.dirs[self.created - 1]
             .try_as_borrowed_fd()
-            .ok_or_else(|| format_err!("lost track of directory file descriptors"))
+            .context("lost track of directory file descriptors")
     }
 
     pub fn create_last_dir(&mut self, allow_existing_dirs: bool) -> Result<(), Error> {
@@ -156,7 +156,7 @@ impl PxarDirStack {
 
         self.dirs[0]
             .try_as_borrowed_fd()
-            .ok_or_else(|| format_err!("lost track of directory file descriptors"))
+            .context("lost track of directory file descriptors")
     }
 
     pub fn path(&self) -> &Path {
diff --git a/pbs-client/src/pxar/extract.rs b/pbs-client/src/pxar/extract.rs
index f6c1991f..7015dc36 100644
--- a/pbs-client/src/pxar/extract.rs
+++ b/pbs-client/src/pxar/extract.rs
@@ -8,7 +8,7 @@ use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 
-use anyhow::{bail, format_err, Error};
+use anyhow::{bail, Context, Error};
 use nix::dir::Dir;
 use nix::fcntl::OFlag;
 use nix::sys::stat::Mode;
@@ -55,8 +55,8 @@ where
 
     let root = decoder
         .next()
-        .ok_or_else(|| format_err!("found empty pxar archive"))?
-        .map_err(|err| format_err!("error reading pxar archive: {}", err))?;
+        .context("found empty pxar archive")?
+        .context("error reading pxar archive")?;
 
     if !root.is_dir() {
         bail!("pxar archive does not start with a directory entry!");
@@ -67,14 +67,14 @@ where
         None,
         Some(CreateOptions::new().perm(Mode::from_bits_truncate(0o700))),
     )
-    .map_err(|err| format_err!("error creating directory {:?}: {}", destination, err))?;
+    .with_context(|| format!("error creating directory {:?}", destination))?;
 
     let dir = Dir::open(
         destination,
         OFlag::O_DIRECTORY | OFlag::O_CLOEXEC,
         Mode::empty(),
     )
-    .map_err(|err| format_err!("unable to open target directory {:?}: {}", destination, err,))?;
+    .with_context(|| format!("unable to open target directory {:?}", destination))?;
 
     let mut extractor = Extractor::new(
         dir,
@@ -92,7 +92,7 @@ where
     let mut err_path_stack = vec![OsString::from("/")];
     let mut current_match = options.extract_match_default;
     while let Some(entry) = decoder.next() {
-        let entry = entry.map_err(|err| format_err!("error reading pxar archive: {}", err))?;
+        let entry = entry.context("error reading pxar archive")?;
 
         let file_name_os = entry.file_name();
 
@@ -102,7 +102,7 @@ where
         }
 
         let file_name = CString::new(file_name_os.as_bytes())
-            .map_err(|_| format_err!("encountered file name with null-bytes"))?;
+            .context("encountered file name with null-bytes")?;
 
         let metadata = entry.metadata();
 
@@ -125,7 +125,7 @@ where
                 let create = current_match && match_result != Some(MatchType::Exclude);
                 extractor
                     .enter_directory(file_name_os.to_owned(), metadata.clone(), create)
-                    .map_err(|err| format_err!("error at entry {:?}: {}", file_name_os, err))?;
+                    .with_context(|| format!("error at entry {:?}", file_name_os))?;
 
                 // We're starting a new directory, push our old matching state and replace it with
                 // our new one:
@@ -142,16 +142,16 @@ where
             (_, EntryKind::GoodbyeTable) => {
                 // go up a directory
 
-                extractor.set_path(err_path_stack.pop().ok_or_else(|| {
-                    format_err!(
-                        "error at entry {:?}: unexpected end of directory",
+                extractor.set_path(err_path_stack.pop().with_context(|| {
+                    format!(
+                        "error at entry {:?} - unexpected end of directory",
                         file_name_os
                     )
                 })?);
 
                 extractor
                     .leave_directory()
-                    .map_err(|err| format_err!("error at entry {:?}: {}", file_name_os, err))?;
+                    .with_context(|| format!("error at entry {:?}", file_name_os))?;
 
                 // We left a directory, also get back our previous matching state. This is in sync
                 // with `dir_stack` so this should never be empty except for the final goodbye
@@ -196,14 +196,14 @@ where
                 &file_name,
                 metadata,
                 *size,
-                &mut decoder.contents().ok_or_else(|| {
-                    format_err!("found regular file entry without contents in archive")
-                })?,
+                &mut decoder
+                    .contents()
+                    .context("found regular file entry without contents in archive")?,
                 extractor.overwrite,
             ),
             (false, _) => Ok(()), // skip this
         }
-        .map_err(|err| format_err!("error at entry {:?}: {}", file_name_os, err))?;
+        .with_context(|| format!("error at entry {:?}", file_name_os))?;
     }
 
     if !extractor.dir_stack.is_empty() {
@@ -254,7 +254,7 @@ impl Extractor {
     pub fn on_error(&mut self, mut on_error: Box<dyn FnMut(Error) -> Result<(), Error> + Send>) {
         let path = Arc::clone(&self.current_path);
         self.on_error = Box::new(move |err: Error| -> Result<(), Error> {
-            on_error(format_err!("error at {:?}: {}", path.lock().unwrap(), err))
+            on_error(err.context(format!("error at {:?}", path.lock().unwrap())))
         });
     }
 
@@ -291,8 +291,8 @@ impl Extractor {
         let dir = self
             .dir_stack
             .pop()
-            .map_err(|err| format_err!("unexpected end of directory entry: {}", err))?
-            .ok_or_else(|| format_err!("broken pxar archive (directory stack underrun)"))?;
+            .context("unexpected end of directory entry")?
+            .context("broken pxar archive (directory stack underrun)")?;
 
         if let Some(fd) = dir.try_as_borrowed_fd() {
             metadata::apply(
@@ -302,7 +302,7 @@ impl Extractor {
                 &path_info,
                 &mut self.on_error,
             )
-            .map_err(|err| format_err!("failed to apply directory metadata: {}", err))?;
+            .context("failed to apply directory metadata")?;
         }
 
         Ok(())
@@ -316,7 +316,7 @@ impl Extractor {
         self.dir_stack
             .last_dir_fd(self.allow_existing_dirs)
             .map(|d| d.as_raw_fd())
-            .map_err(|err| format_err!("failed to get parent directory file descriptor: {}", err))
+            .context("failed to get parent directory file descriptor")
     }
 
     pub fn extract_symlink(
@@ -370,16 +370,12 @@ impl Extractor {
         device: libc::dev_t,
     ) -> Result<(), Error> {
         let mode = metadata.stat.mode;
-        let mode = u32::try_from(mode).map_err(|_| {
-            format_err!(
-                "device node's mode contains illegal bits: 0x{:x} (0o{:o})",
-                mode,
-                mode,
-            )
+        let mode = u32::try_from(mode).with_context(|| {
+            format!("device node's mode contains illegal bits: 0x{mode:x} (0o{mode:o})")
         })?;
         let parent = self.parent_fd()?;
         unsafe { c_result!(libc::mknodat(parent, file_name.as_ptr(), mode, device)) }
-            .map_err(|err| format_err!("failed to create device node: {}", err))?;
+            .context("failed to create device node")?;
 
         metadata::apply_at(
             self.feature_flags,
@@ -409,7 +405,7 @@ impl Extractor {
         let mut file = unsafe {
             std::fs::File::from_raw_fd(
                 nix::fcntl::openat(parent, file_name, oflags, Mode::from_bits(0o600).unwrap())
-                    .map_err(|err| format_err!("failed to create file {:?}: {}", file_name, err))?,
+                    .with_context(|| format!("failed to create file {file_name:?}"))?,
             )
         };
 
@@ -419,10 +415,10 @@ impl Extractor {
             file.as_raw_fd(),
             &mut self.on_error,
         )
-        .map_err(|err| format_err!("failed to apply initial flags: {}", err))?;
+        .context("failed to apply initial flags")?;
 
-        let result = sparse_copy(&mut *contents, &mut file)
-            .map_err(|err| format_err!("failed to copy file contents: {}", err))?;
+        let result =
+            sparse_copy(&mut *contents, &mut file).context("failed to copy file contents")?;
 
         if size != result.written {
             bail!(
@@ -436,7 +432,7 @@ impl Extractor {
             while match nix::unistd::ftruncate(file.as_raw_fd(), size as i64) {
                 Ok(_) => false,
                 Err(errno) if errno == nix::errno::Errno::EINTR => true,
-                Err(err) => bail!("error setting file size: {}", err),
+                Err(err) => return Err(err).context("error setting file size"),
             } {}
         }
 
@@ -467,7 +463,7 @@ impl Extractor {
         let mut file = tokio::fs::File::from_std(unsafe {
             std::fs::File::from_raw_fd(
                 nix::fcntl::openat(parent, file_name, oflags, Mode::from_bits(0o600).unwrap())
-                    .map_err(|err| format_err!("failed to create file {:?}: {}", file_name, err))?,
+                    .with_context(|| format!("failed to create file {file_name:?}"))?,
             )
         });
 
@@ -477,11 +473,11 @@ impl Extractor {
             file.as_raw_fd(),
             &mut self.on_error,
         )
-        .map_err(|err| format_err!("failed to apply initial flags: {}", err))?;
+        .context("failed to apply initial flags")?;
 
         let result = sparse_copy_async(&mut *contents, &mut file)
             .await
-            .map_err(|err| format_err!("failed to copy file contents: {}", err))?;
+            .context("failed to copy file contents")?;
 
         if size != result.written {
             bail!(
@@ -495,7 +491,7 @@ impl Extractor {
             while match nix::unistd::ftruncate(file.as_raw_fd(), size as i64) {
                 Ok(_) => false,
                 Err(errno) if errno == nix::errno::Errno::EINTR => true,
-                Err(err) => bail!("error setting file size: {}", err),
+                Err(err) => return Err(err).context("error setting file size"),
             } {}
         }
 
@@ -532,12 +528,12 @@ where
     header.set_size(size);
     add_metadata_to_header(&mut header, metadata);
     header.set_cksum();
+
     match contents {
         Some(content) => tar.add_entry(&mut header, path, content).await,
         None => tar.add_entry(&mut header, path, tokio::io::empty()).await,
     }
-    .map_err(|err| format_err!("could not send file entry: {}", err))?;
-    Ok(())
+    .context("could not send file entry")
 }
 
 /// Creates a tar file from `path` and writes it into `output`
@@ -551,7 +547,7 @@ where
     let file = root
         .lookup(&path)
         .await?
-        .ok_or_else(|| format_err!("error opening '{:?}'", path.as_ref()))?;
+        .with_context(|| format!("error opening {:?}", path.as_ref()))?;
 
     let mut components = file.entry().path().components();
     components.next_back(); // discard last
@@ -574,13 +570,13 @@ where
             tarencoder
                 .add_entry(&mut header, path, tokio::io::empty())
                 .await
-                .map_err(|err| format_err!("could not send dir entry: {}", err))?;
+                .context("could not send dir entry")?;
         }
 
         let mut decoder = dir.decode_full().await?;
         decoder.enable_goodbye_entries(false);
         while let Some(entry) = decoder.next().await {
-            let entry = entry.map_err(|err| format_err!("cannot decode entry: {}", err))?;
+            let entry = entry.context("cannot decode entry")?;
 
             let metadata = entry.metadata();
             let path = entry.path().strip_prefix(prefix)?;
@@ -595,7 +591,7 @@ where
                         let entry = root
                             .lookup(&path)
                             .await?
-                            .ok_or_else(|| format_err!("error looking up '{:?}'", path))?;
+                            .with_context(|| format!("error looking up {path:?}"))?;
                         let realfile = accessor.follow_hardlink(&entry).await?;
                         let metadata = realfile.entry().metadata();
                         let realpath = Path::new(link);
@@ -630,7 +626,7 @@ where
                         tarencoder
                             .add_link(&mut header, path, stripped_path)
                             .await
-                            .map_err(|err| format_err!("could not send hardlink entry: {}", err))?;
+                            .context("could not send hardlink entry")?;
                     }
                 }
                 EntryKind::Symlink(link) if !link.data.is_empty() => {
@@ -643,7 +639,7 @@ where
                     tarencoder
                         .add_link(&mut header, path, realpath)
                         .await
-                        .map_err(|err| format_err!("could not send symlink entry: {}", err))?;
+                        .context("could not send symlink entry")?;
                 }
                 EntryKind::Fifo => {
                     log::debug!("adding '{}' to tar", path.display());
@@ -657,7 +653,7 @@ where
                     tarencoder
                         .add_entry(&mut header, path, tokio::io::empty())
                         .await
-                        .map_err(|err| format_err!("could not send fifo entry: {}", err))?;
+                        .context("coult not send fifo entry")?;
                 }
                 EntryKind::Directory => {
                     log::debug!("adding '{}' to tar", path.display());
@@ -671,7 +667,7 @@ where
                         tarencoder
                             .add_entry(&mut header, path, tokio::io::empty())
                             .await
-                            .map_err(|err| format_err!("could not send dir entry: {}", err))?;
+                            .context("could not send dir entry")?;
                     }
                 }
                 EntryKind::Device(device) => {
@@ -690,7 +686,7 @@ where
                     tarencoder
                         .add_entry(&mut header, path, tokio::io::empty())
                         .await
-                        .map_err(|err| format_err!("could not send device entry: {}", err))?;
+                        .context("could not send device entry")?;
                 }
                 _ => {} // ignore all else
             }
@@ -714,7 +710,7 @@ where
     let file = root
         .lookup(&path)
         .await?
-        .ok_or_else(|| format_err!("error opening '{:?}'", path.as_ref()))?;
+        .with_context(|| format!("error opening {:?}", path.as_ref()))?;
 
     let prefix = {
         let mut components = file.entry().path().components();
@@ -756,13 +752,13 @@ where
                     );
                     zip.add_entry(entry, decoder.contents())
                         .await
-                        .map_err(|err| format_err!("could not send file entry: {}", err))?;
+                        .context("could not send file entry")?;
                 }
                 EntryKind::Hardlink(_) => {
                     let entry = root
                         .lookup(&path)
                         .await?
-                        .ok_or_else(|| format_err!("error looking up '{:?}'", path))?;
+                        .with_context(|| format!("error looking up {:?}", path))?;
                     let realfile = accessor.follow_hardlink(&entry).await?;
                     let metadata = realfile.entry().metadata();
                     log::debug!("adding '{}' to zip", path.display());
@@ -774,7 +770,7 @@ where
                     );
                     zip.add_entry(entry, decoder.contents())
                         .await
-                        .map_err(|err| format_err!("could not send file entry: {}", err))?;
+                        .context("could not send file entry")?;
                 }
                 EntryKind::Directory => {
                     log::debug!("adding '{}' to zip", path.display());
@@ -806,26 +802,14 @@ where
         None,
         Some(CreateOptions::new().perm(Mode::from_bits_truncate(0o700))),
     )
-    .map_err(|err| {
-        format_err!(
-            "error creating directory {:?}: {}",
-            destination.as_ref(),
-            err
-        )
-    })?;
+    .with_context(|| format!("error creating directory {:?}", destination.as_ref()))?;
 
     let dir = Dir::open(
         destination.as_ref(),
         OFlag::O_DIRECTORY | OFlag::O_CLOEXEC,
         Mode::empty(),
     )
-    .map_err(|err| {
-        format_err!(
-            "unable to open target directory {:?}: {}",
-            destination.as_ref(),
-            err,
-        )
-    })?;
+    .with_context(|| format!("unable to open target directory {:?}", destination.as_ref()))?;
 
     Ok(Extractor::new(dir, metadata, false, false, Flags::DEFAULT))
 }
@@ -850,7 +834,7 @@ where
     let file = root
         .lookup(&path)
         .await?
-        .ok_or_else(|| format_err!("error opening '{:?}'", path.as_ref()))?;
+        .with_context(|| format!("error opening {:?}", path.as_ref()))?;
 
     recurse_files_extractor(&mut extractor, file).await
 }
@@ -866,7 +850,7 @@ where
     decoder.enable_goodbye_entries(true);
     let root = match decoder.next().await {
         Some(Ok(root)) => root,
-        Some(Err(err)) => bail!("error getting root entry from pxar: {}", err),
+        Some(Err(err)) => return Err(err).context("error getting root entry from pxar"),
         None => bail!("cannot extract empty archive"),
     };
 
@@ -920,8 +904,8 @@ fn get_filename(entry: &Entry) -> Result<(OsString, CString), Error> {
         bail!("archive file entry contains slashes, which is invalid and a security concern");
     }
 
-    let file_name = CString::new(file_name_os.as_bytes())
-        .map_err(|_| format_err!("encountered file name with null-bytes"))?;
+    let file_name =
+        CString::new(file_name_os.as_bytes()).context("encountered file name with null-bytes")?;
 
     Ok((file_name_os, file_name))
 }
@@ -943,7 +927,7 @@ where
         EntryKind::Directory => {
             extractor
                 .enter_directory(file_name_os.to_owned(), metadata.clone(), true)
-                .map_err(|err| format_err!("error at entry {:?}: {}", file_name_os, err))?;
+                .with_context(|| format!("error at entry {file_name_os:?}"))?;
 
             let dir = file.enter_directory().await?;
             let mut seq_decoder = dir.decode_full().await?;
@@ -957,9 +941,10 @@ where
                     &file_name,
                     metadata,
                     *size,
-                    &mut file.contents().await.map_err(|_| {
-                        format_err!("found regular file entry without contents in archive")
-                    })?,
+                    &mut file
+                        .contents()
+                        .await
+                        .context("found regular file entry without contents in archive")?,
                     extractor.overwrite,
                 )
                 .await?
@@ -997,7 +982,7 @@ where
                     dir_level += 1;
                     extractor
                         .enter_directory(file_name_os.to_owned(), metadata.clone(), true)
-                        .map_err(|err| format_err!("error at entry {:?}: {}", file_name_os, err))?;
+                        .with_context(|| format!("error at entry {file_name_os:?}"))?;
                 }
                 EntryKind::File { size, .. } => {
                     extractor
@@ -1005,9 +990,9 @@ where
                             &file_name,
                             metadata,
                             *size,
-                            &mut decoder.contents().ok_or_else(|| {
-                                format_err!("found regular file entry without contents in archive")
-                            })?,
+                            &mut decoder
+                                .contents()
+                                .context("found regular file entry without contents in archive")?,
                             extractor.overwrite,
                         )
                         .await?
diff --git a/pbs-client/src/pxar/metadata.rs b/pbs-client/src/pxar/metadata.rs
index cff3cb34..745785bf 100644
--- a/pbs-client/src/pxar/metadata.rs
+++ b/pbs-client/src/pxar/metadata.rs
@@ -2,7 +2,7 @@ use std::ffi::{CStr, CString};
 use std::os::unix::io::{AsRawFd, RawFd};
 use std::path::Path;
 
-use anyhow::{bail, format_err, Error};
+use anyhow::{anyhow, bail, Context, Error};
 use nix::errno::Errno;
 use nix::fcntl::OFlag;
 use nix::sys::stat::Mode;
@@ -106,7 +106,7 @@ pub fn apply(
         .or_else(&mut *on_error)?;
     add_fcaps(flags, c_proc_path.as_ptr(), metadata, &mut skip_xattrs).or_else(&mut *on_error)?;
     apply_acls(flags, &c_proc_path, metadata, path_info)
-        .map_err(|err| format_err!("failed to apply acls: {}", err))
+        .context("failed to apply acls")
         .or_else(&mut *on_error)?;
     apply_quota_project_id(flags, fd, metadata).or_else(&mut *on_error)?;
 
@@ -118,7 +118,7 @@ pub fn apply(
         })
         .map(drop)
         .or_else(allow_notsupp)
-        .map_err(|err| format_err!("failed to change file mode: {}", err))
+        .context("failed to change file mode")
         .or_else(&mut *on_error)?;
     }
 
@@ -134,11 +134,9 @@ pub fn apply(
         Ok(_) => (),
         Err(ref err) if err.is_errno(Errno::EOPNOTSUPP) => (),
         Err(err) => {
-            on_error(format_err!(
-                "failed to restore mtime attribute on {:?}: {}",
-                path_info,
-                err
-            ))?;
+            on_error(anyhow!(err).context(format!(
+                "failed to restore mtime attribute on {path_info:?}"
+            )))?;
         }
     }
 
@@ -167,7 +165,7 @@ pub fn apply_ownership(
         ))
         .map(drop)
         .or_else(allow_notsupp)
-        .map_err(|err| format_err!("failed to set ownership: {}", err))
+        .context("failed to set ownership")
         .or_else(&mut *on_error)?;
     }
     Ok(())
@@ -198,9 +196,7 @@ fn add_fcaps(
     })
     .map(drop)
     .or_else(|err| allow_notsupp_remember(err, skip_xattrs))
-    .map_err(|err| format_err!("failed to apply file capabilities: {}", err))?;
-
-    Ok(())
+    .context("failed to apply file capabilities")
 }
 
 fn apply_xattrs(
@@ -234,7 +230,7 @@ fn apply_xattrs(
         })
         .map(drop)
         .or_else(|err| allow_notsupp_remember(err, &mut *skip_xattrs))
-        .map_err(|err| format_err!("failed to apply extended attributes: {}", err))?;
+        .context("failed to apply extended attributes")?;
     }
 
     Ok(())
@@ -348,21 +344,13 @@ fn apply_quota_project_id(flags: Flags, fd: RawFd, metadata: &Metadata) -> Resul
 
     let mut fsxattr = fs::FSXAttr::default();
     unsafe {
-        fs::fs_ioc_fsgetxattr(fd, &mut fsxattr).map_err(|err| {
-            format_err!(
-                "error while getting fsxattr to restore quota project id - {}",
-                err
-            )
-        })?;
+        fs::fs_ioc_fsgetxattr(fd, &mut fsxattr)
+            .context("error while getting fsxattr to restore quota project id")?;
 
         fsxattr.fsx_projid = projid.projid as u32;
 
-        fs::fs_ioc_fssetxattr(fd, &fsxattr).map_err(|err| {
-            format_err!(
-                "error while setting fsxattr to restore quota project id - {}",
-                err
-            )
-        })?;
+        fs::fs_ioc_fssetxattr(fd, &fsxattr)
+            .context("error while setting fsxattr to restore quota project id")?;
     }
 
     Ok(())
@@ -386,7 +374,7 @@ fn apply_chattr(fd: RawFd, chattr: libc::c_long, mask: libc::c_long) -> Result<(
         Err(errno) if errno_is_unsupported(errno) => {
             return Ok(());
         }
-        Err(err) => bail!("failed to read file attributes: {}", err),
+        Err(err) => return Err(err).context("failed to read file attributes"),
     }
 
     let attr = (chattr & mask) | (fattr & !mask);
@@ -398,7 +386,7 @@ fn apply_chattr(fd: RawFd, chattr: libc::c_long, mask: libc::c_long) -> Result<(
     match unsafe { fs::write_attr_fd(fd, &attr) } {
         Ok(_) => Ok(()),
         Err(errno) if errno_is_unsupported(errno) => Ok(()),
-        Err(err) => bail!("failed to set file attributes: {}", err),
+        Err(err) => Err(err).context("failed to set file attributes"),
     }
 }
 
@@ -412,7 +400,7 @@ fn apply_flags(flags: Flags, fd: RawFd, entry_flags: u64) -> Result<(), Error> {
         match unsafe { fs::write_fat_attr_fd(fd, &fatattr) } {
             Ok(_) => (),
             Err(errno) if errno_is_unsupported(errno) => (),
-            Err(err) => bail!("failed to set file FAT attributes: {}", err),
+            Err(err) => return Err(err).context("failed to set file FAT attributes"),
         }
     }
 
diff --git a/pbs-client/src/pxar/tools.rs b/pbs-client/src/pxar/tools.rs
index 844a0f73..0cfbaf5b 100644
--- a/pbs-client/src/pxar/tools.rs
+++ b/pbs-client/src/pxar/tools.rs
@@ -4,7 +4,7 @@ use std::ffi::OsStr;
 use std::os::unix::ffi::OsStrExt;
 use std::path::Path;
 
-use anyhow::{bail, format_err, Error};
+use anyhow::{bail, Context, Error};
 use nix::sys::stat::Mode;
 
 use pxar::{format::StatxTimestamp, mode, Entry, EntryKind, Metadata};
@@ -12,10 +12,13 @@ use pxar::{format::StatxTimestamp, mode, Entry, EntryKind, Metadata};
 /// Get the file permissions as `nix::Mode`
 pub fn perms_from_metadata(meta: &Metadata) -> Result<Mode, Error> {
     let mode = meta.stat.get_permission_bits();
+
     u32::try_from(mode)
-        .map_err(drop)
-        .and_then(|mode| Mode::from_bits(mode).ok_or(()))
-        .map_err(|_| format_err!("mode contains illegal bits: 0x{:x} (0o{:o})", mode, mode))
+        .context("couldn't narrow permission bits")
+        .and_then(|mode| {
+            Mode::from_bits(mode)
+                .with_context(|| format!("mode contains illegal bits: 0x{:x} (0o{:o})", mode, mode))
+        })
 }
 
 /// Make sure path is relative and not '.' or '..'.
-- 
2.39.2

[pbs-devel] [PATCH v2 proxmox-backup 2/5] pbs-client: pxar: refactor body of `extract_archive` to `ExtractorIter`

[Max Carrara]

This change factors the body of `extract_archive()` into a separate
struct named `ExtractorIter` which implements the `Iterator` trait.

This refactor has two goals:
  * Make it easier to provide and propagate errors and additional
    information via `anyhow::Context`
  * Introduce a means to handle errors that occur during extraction,
    with the possibility to continue extraction if the handler decides
    that the error is not fatal

The latter point benefits from the information provided by the former;
previously, errors could only be handled in certain locations
(e.g. application of metadata), but not on a "per-entry" basis.

Since `extract_archive()` was already using a "desugared" version of
the iterator pattern to begin with, wrapping its body up in an actual
`Iterator` made the most sense, as it didn't require changing the already
existing control flow that much.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---
 Changes v1 --> v2:
  * Get rid of `next_entry()` function of `ExtractorIter` in order to avoid
    needless `.unwrap()`s and double allocation of file name string
  * Use `format_err!` instead of `anyhow!`
  * Use diverging `match` instead of checking `is_none()` / `is_some()` / etc.

 pbs-client/src/pxar/extract.rs | 361 +++++++++++++++++++++++----------
 1 file changed, 251 insertions(+), 110 deletions(-)

diff --git a/pbs-client/src/pxar/extract.rs b/pbs-client/src/pxar/extract.rs
index 7015dc36..bc51d4e8 100644
--- a/pbs-client/src/pxar/extract.rs
+++ b/pbs-client/src/pxar/extract.rs
@@ -8,7 +8,7 @@ use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 
-use anyhow::{bail, Context, Error};
+use anyhow::{bail, format_err, Context, Error};
 use nix::dir::Dir;
 use nix::fcntl::OFlag;
 use nix::sys::stat::Mode;
@@ -40,75 +40,203 @@ pub struct PxarExtractOptions<'a> {
 pub type ErrorHandler = Box<dyn FnMut(Error) -> Result<(), Error> + Send>;
 
 pub fn extract_archive<T, F>(
-    mut decoder: pxar::decoder::Decoder<T>,
+    decoder: pxar::decoder::Decoder<T>,
     destination: &Path,
     feature_flags: Flags,
-    mut callback: F,
+    callback: F,
     options: PxarExtractOptions,
 ) -> Result<(), Error>
 where
     T: pxar::decoder::SeqRead,
     F: FnMut(&Path),
 {
-    // we use this to keep track of our directory-traversal
-    decoder.enable_goodbye_entries(true);
+    ExtractorIter::new(decoder, destination, feature_flags, callback, options)
+        .context("failed to initialize extractor")?
+        .collect::<Result<(), Error>>()
+        .context("encountered unexpected error during extraction")
+}
 
-    let root = decoder
-        .next()
-        .context("found empty pxar archive")?
-        .context("error reading pxar archive")?;
+struct ExtractorIterState {
+    match_stack: Vec<bool>,
+    err_path_stack: Vec<OsString>,
+    current_match: bool,
+    end_reached: bool,
+}
+
+/// An [`Iterator`] that encapsulates the process of extraction in [extract_archive].
+/// Therefore, traversing over an [`ExtractorIter`] until exhaustion extracts an
+/// entire PXAR archive.
+struct ExtractorIter<'a, T, F>
+where
+    T: pxar::decoder::SeqRead,
+    F: FnMut(&Path),
+{
+    decoder: pxar::decoder::Decoder<T>,
+    callback: F,
+    extractor: Extractor,
+    match_list: &'a [MatchEntry],
+    state: ExtractorIterState,
+}
 
-    if !root.is_dir() {
-        bail!("pxar archive does not start with a directory entry!");
+impl ExtractorIterState {
+    fn new(options: &PxarExtractOptions) -> Self {
+        Self {
+            match_stack: Vec::new(),
+            err_path_stack: Vec::new(),
+            current_match: options.extract_match_default,
+            end_reached: false,
+        }
     }
+}
 
-    create_path(
-        destination,
-        None,
-        Some(CreateOptions::new().perm(Mode::from_bits_truncate(0o700))),
-    )
-    .with_context(|| format!("error creating directory {:?}", destination))?;
+impl<'a, T, F> ExtractorIter<'a, T, F>
+where
+    T: pxar::decoder::SeqRead,
+    F: FnMut(&Path),
+{
+    /// Creates and initializes the state of a new [`ExtractorIter`].
+    ///
+    /// This function requires that the given [`Decoder`][D] has not made a single
+    /// traversal (a call to [`next()`][next]) yet.
+    ///
+    /// [D]: pxar::decoder::Decoder
+    /// [next]: std::iter::Iterator::next()
+    fn new(
+        mut decoder: pxar::decoder::Decoder<T>,
+        destination: &Path,
+        feature_flags: Flags,
+        callback: F,
+        options: PxarExtractOptions<'a>,
+    ) -> Result<Self, Error> {
+        // we use this to keep track of our directory-traversal
+        decoder.enable_goodbye_entries(true);
+
+        let root = decoder
+            .next()
+            .context("found empty pxar archive")?
+            .context("error reading pxar archive")?;
+
+        if !root.is_dir() {
+            bail!("pxar archive does not start with a directory entry!");
+        }
 
-    let dir = Dir::open(
-        destination,
-        OFlag::O_DIRECTORY | OFlag::O_CLOEXEC,
-        Mode::empty(),
-    )
-    .with_context(|| format!("unable to open target directory {:?}", destination))?;
-
-    let mut extractor = Extractor::new(
-        dir,
-        root.metadata().clone(),
-        options.allow_existing_dirs,
-        options.overwrite,
-        feature_flags,
-    );
-
-    if let Some(on_error) = options.on_error {
-        extractor.on_error(on_error);
+        let mut state = ExtractorIterState::new(&options);
+        state.err_path_stack.push(OsString::from("/"));
+
+        create_path(
+            destination,
+            None,
+            Some(CreateOptions::new().perm(Mode::from_bits_truncate(0o700))),
+        )
+        .with_context(|| format!("error creating directory {destination:?}"))?;
+
+        let dir = Dir::open(
+            destination,
+            OFlag::O_DIRECTORY | OFlag::O_CLOEXEC,
+            Mode::empty(),
+        )
+        .with_context(|| format!("unable to open target directory {destination:?}"))?;
+
+        let mut extractor = Extractor::new(
+            dir,
+            root.metadata().clone(),
+            options.allow_existing_dirs,
+            options.overwrite,
+            feature_flags,
+        );
+
+        if let Some(on_error) = options.on_error {
+            extractor.on_error(on_error);
+        }
+
+        Ok(Self {
+            decoder,
+            callback,
+            extractor,
+            match_list: options.match_list,
+            state,
+        })
     }
 
-    let mut match_stack = Vec::new();
-    let mut err_path_stack = vec![OsString::from("/")];
-    let mut current_match = options.extract_match_default;
-    while let Some(entry) = decoder.next() {
-        let entry = entry.context("error reading pxar archive")?;
+    #[inline(always)]
+    fn callback(&mut self, path: &Path) {
+        (self.callback)(path)
+    }
+}
+
+impl<'a, T, F> Iterator for ExtractorIter<'a, T, F>
+where
+    T: pxar::decoder::SeqRead,
+    F: FnMut(&Path),
+{
+    type Item = Result<(), Error>;
+
+    /// Performs the extraction of [`Entries`][E] yielded by the [`Decoder`][D].
+    ///
+    /// In detail, the [`ExtractorIter`] will stop if and only if one of the
+    /// following conditions is true:
+    ///   * The [`Decoder`][D] is exhausted
+    ///   * The [`Decoder`][D] failed to read from the archive and consequently
+    ///     yielded an [`io::Error`]
+    ///   * The [`Entry`][E]'s filename is invalid (contains nul bytes or a slash)
+    ///
+    /// Should an error occur during any point of extraction (**not** while
+    /// fetching the next [`Entry`][E]), the error may be handled by the
+    /// [`ErrorHandler`] provided by the [`PxarExtractOptions`] used to
+    /// initialize the iterator.
+    ///
+    /// [E]: pxar::Entry
+    /// [D]: pxar::decoder::Decoder
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.state.end_reached {
+            return None;
+        }
+
+        let entry = match self.decoder.next() {
+            None => {
+                self.state.end_reached = true;
+
+                if !self.extractor.dir_stack.is_empty() {
+                    return Some(Err(format_err!(
+                        "unexpected eof while decoding pxar archive"
+                    )));
+                } else {
+                    return None;
+                }
+            }
+            Some(Err(err)) => {
+                self.state.end_reached = true;
+
+                return Some(Err(format_err!(err).context("error reading pxar archive")));
+            }
+            Some(Ok(entry)) => entry,
+        };
 
         let file_name_os = entry.file_name();
+        let file_name_bytes = file_name_os.as_bytes();
 
-        // safety check: a file entry in an archive must never contain slashes:
-        if file_name_os.as_bytes().contains(&b'/') {
-            bail!("archive file entry contains slashes, which is invalid and a security concern");
+        if file_name_bytes.contains(&b'/') {
+            self.state.end_reached = true;
+
+            return Some(Err(format_err!(
+                "archive file entry contains slashes, which is invalid and a security concern"
+            )));
         }
 
-        let file_name = CString::new(file_name_os.as_bytes())
-            .context("encountered file name with null-bytes")?;
+        let file_name = match CString::new(file_name_bytes) {
+            Err(err) => {
+                self.state.end_reached = true;
+
+                return Some(Err(format_err!(err)));
+            }
+            Ok(file_name_ref) => file_name_ref,
+        };
 
         let metadata = entry.metadata();
 
-        extractor.set_path(entry.path().as_os_str().to_owned());
+        self.extractor.set_path(entry.path().as_os_str().to_owned());
 
-        let match_result = options.match_list.matches(
+        let match_result = self.match_list.matches(
             entry.path().as_os_str().as_bytes(),
             Some(metadata.file_type() as u32),
         );
@@ -116,101 +244,114 @@ where
         let did_match = match match_result {
             Some(MatchType::Include) => true,
             Some(MatchType::Exclude) => false,
-            None => current_match,
+            None => self.state.current_match,
         };
-        match (did_match, entry.kind()) {
-            (_, EntryKind::Directory) => {
-                callback(entry.path());
-
-                let create = current_match && match_result != Some(MatchType::Exclude);
-                extractor
-                    .enter_directory(file_name_os.to_owned(), metadata.clone(), create)
-                    .with_context(|| format!("error at entry {:?}", file_name_os))?;
-
-                // We're starting a new directory, push our old matching state and replace it with
-                // our new one:
-                match_stack.push(current_match);
-                current_match = did_match;
 
-                // When we hit the goodbye table we'll try to apply metadata to the directory, but
-                // the Goodbye entry will not contain the path, so push it to our path stack for
-                // error messages:
-                err_path_stack.push(extractor.clone_path());
+        let extract_res = match (did_match, entry.kind()) {
+            (_, EntryKind::Directory) => {
+                self.callback(entry.path());
+
+                let create = self.state.current_match && match_result != Some(MatchType::Exclude);
+                let res = self.extractor.enter_directory(
+                    file_name_os.to_owned(),
+                    metadata.clone(),
+                    create,
+                );
+
+                if res.is_ok() {
+                    // We're starting a new directory, push our old matching state and replace it with
+                    // our new one:
+                    self.state.match_stack.push(self.state.current_match);
+                    self.state.current_match = did_match;
+
+                    // When we hit the goodbye table we'll try to apply metadata to the directory, but
+                    // the Goodbye entry will not contain the path, so push it to our path stack for
+                    // error messages:
+                    self.state.err_path_stack.push(self.extractor.clone_path());
+                }
 
-                Ok(())
+                res
             }
             (_, EntryKind::GoodbyeTable) => {
                 // go up a directory
 
-                extractor.set_path(err_path_stack.pop().with_context(|| {
-                    format!(
-                        "error at entry {:?} - unexpected end of directory",
-                        file_name_os
-                    )
-                })?);
-
-                extractor
-                    .leave_directory()
-                    .with_context(|| format!("error at entry {:?}", file_name_os))?;
-
-                // We left a directory, also get back our previous matching state. This is in sync
-                // with `dir_stack` so this should never be empty except for the final goodbye
-                // table, in which case we get back to the default of `true`.
-                current_match = match_stack.pop().unwrap_or(true);
+                let res = self
+                    .state
+                    .err_path_stack
+                    .pop()
+                    .context("unexpected end of directory")
+                    .map(|path| self.extractor.set_path(path))
+                    .and(self.extractor.leave_directory());
+
+                if res.is_ok() {
+                    // We left a directory, also get back our previous matching state. This is in sync
+                    // with `dir_stack` so this should never be empty except for the final goodbye
+                    // table, in which case we get back to the default of `true`.
+                    self.state.current_match = self.state.match_stack.pop().unwrap_or(true);
+                }
 
-                Ok(())
+                res
             }
             (true, EntryKind::Symlink(link)) => {
-                callback(entry.path());
-                extractor.extract_symlink(&file_name, metadata, link.as_ref())
+                self.callback(entry.path());
+                self.extractor
+                    .extract_symlink(&file_name, metadata, link.as_ref())
             }
             (true, EntryKind::Hardlink(link)) => {
-                callback(entry.path());
-                extractor.extract_hardlink(&file_name, link.as_os_str())
+                self.callback(entry.path());
+                self.extractor
+                    .extract_hardlink(&file_name, link.as_os_str())
             }
             (true, EntryKind::Device(dev)) => {
-                if extractor.contains_flags(Flags::WITH_DEVICE_NODES) {
-                    callback(entry.path());
-                    extractor.extract_device(&file_name, metadata, dev)
+                if self.extractor.contains_flags(Flags::WITH_DEVICE_NODES) {
+                    self.callback(entry.path());
+                    self.extractor.extract_device(&file_name, metadata, dev)
                 } else {
                     Ok(())
                 }
             }
             (true, EntryKind::Fifo) => {
-                if extractor.contains_flags(Flags::WITH_FIFOS) {
-                    callback(entry.path());
-                    extractor.extract_special(&file_name, metadata, 0)
+                if self.extractor.contains_flags(Flags::WITH_FIFOS) {
+                    self.callback(entry.path());
+                    self.extractor.extract_special(&file_name, metadata, 0)
                 } else {
                     Ok(())
                 }
             }
             (true, EntryKind::Socket) => {
-                if extractor.contains_flags(Flags::WITH_SOCKETS) {
-                    callback(entry.path());
-                    extractor.extract_special(&file_name, metadata, 0)
+                if self.extractor.contains_flags(Flags::WITH_SOCKETS) {
+                    self.callback(entry.path());
+                    self.extractor.extract_special(&file_name, metadata, 0)
                 } else {
                     Ok(())
                 }
             }
-            (true, EntryKind::File { size, .. }) => extractor.extract_file(
-                &file_name,
-                metadata,
-                *size,
-                &mut decoder
-                    .contents()
-                    .context("found regular file entry without contents in archive")?,
-                extractor.overwrite,
-            ),
+            (true, EntryKind::File { size, .. }) => {
+                let contents = self.decoder.contents();
+
+                if let Some(mut contents) = contents {
+                    self.extractor.extract_file(
+                        &file_name,
+                        metadata,
+                        *size,
+                        &mut contents,
+                        self.extractor.overwrite,
+                    )
+                } else {
+                    Err(format_err!(
+                        "found regular file entry without contents in archive"
+                    ))
+                }
+            }
             (false, _) => Ok(()), // skip this
-        }
-        .with_context(|| format!("error at entry {:?}", file_name_os))?;
-    }
+        };
 
-    if !extractor.dir_stack.is_empty() {
-        bail!("unexpected eof while decoding pxar archive");
+        Some(
+            extract_res
+                .with_context(|| format!("error at entry {file_name_os:?}"))
+                .or_else(&mut *self.extractor.on_error),
+        )
     }
-
-    Ok(())
 }
 
 /// Common state for file extraction.
-- 
2.39.2

[pbs-devel] [PATCH v2 proxmox-backup 3/5] pbs-client: pxar: add PxarExtractContext

[Max Carrara]

This enum's purpose is to provide context to errors that occur during
the extraction of a pxar archive, making it possible to handle
extraction errors in a more granular manner.

For now, it's only implemented in `ExtractorIter::next()`, but may be
used in other places if necessary or desired.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---
 Changes v1 --> v2:
  * None

 pbs-client/src/pxar/extract.rs | 98 ++++++++++++++++++++++++++++++----
 pbs-client/src/pxar/mod.rs     |  2 +-
 2 files changed, 90 insertions(+), 10 deletions(-)

diff --git a/pbs-client/src/pxar/extract.rs b/pbs-client/src/pxar/extract.rs
index bc51d4e8..4dbaf52d 100644
--- a/pbs-client/src/pxar/extract.rs
+++ b/pbs-client/src/pxar/extract.rs
@@ -185,6 +185,8 @@ where
     /// [`ErrorHandler`] provided by the [`PxarExtractOptions`] used to
     /// initialize the iterator.
     ///
+    /// Extraction errors will have a corresponding [`PxarExtractContext`] attached.
+    ///
     /// [E]: pxar::Entry
     /// [D]: pxar::decoder::Decoder
     fn next(&mut self) -> Option<Self::Item> {
@@ -252,11 +254,10 @@ where
                 self.callback(entry.path());
 
                 let create = self.state.current_match && match_result != Some(MatchType::Exclude);
-                let res = self.extractor.enter_directory(
-                    file_name_os.to_owned(),
-                    metadata.clone(),
-                    create,
-                );
+                let res = self
+                    .extractor
+                    .enter_directory(file_name_os.to_owned(), metadata.clone(), create)
+                    .context(PxarExtractContext::EnterDirectory);
 
                 if res.is_ok() {
                     // We're starting a new directory, push our old matching state and replace it with
@@ -281,7 +282,8 @@ where
                     .pop()
                     .context("unexpected end of directory")
                     .map(|path| self.extractor.set_path(path))
-                    .and(self.extractor.leave_directory());
+                    .and(self.extractor.leave_directory())
+                    .context(PxarExtractContext::LeaveDirectory);
 
                 if res.is_ok() {
                     // We left a directory, also get back our previous matching state. This is in sync
@@ -296,16 +298,20 @@ where
                 self.callback(entry.path());
                 self.extractor
                     .extract_symlink(&file_name, metadata, link.as_ref())
+                    .context(PxarExtractContext::ExtractSymlink)
             }
             (true, EntryKind::Hardlink(link)) => {
                 self.callback(entry.path());
                 self.extractor
                     .extract_hardlink(&file_name, link.as_os_str())
+                    .context(PxarExtractContext::ExtractHardlink)
             }
             (true, EntryKind::Device(dev)) => {
                 if self.extractor.contains_flags(Flags::WITH_DEVICE_NODES) {
                     self.callback(entry.path());
-                    self.extractor.extract_device(&file_name, metadata, dev)
+                    self.extractor
+                        .extract_device(&file_name, metadata, dev)
+                        .context(PxarExtractContext::ExtractDevice)
                 } else {
                     Ok(())
                 }
@@ -313,7 +319,9 @@ where
             (true, EntryKind::Fifo) => {
                 if self.extractor.contains_flags(Flags::WITH_FIFOS) {
                     self.callback(entry.path());
-                    self.extractor.extract_special(&file_name, metadata, 0)
+                    self.extractor
+                        .extract_special(&file_name, metadata, 0)
+                        .context(PxarExtractContext::ExtractFifo)
                 } else {
                     Ok(())
                 }
@@ -321,7 +329,9 @@ where
             (true, EntryKind::Socket) => {
                 if self.extractor.contains_flags(Flags::WITH_SOCKETS) {
                     self.callback(entry.path());
-                    self.extractor.extract_special(&file_name, metadata, 0)
+                    self.extractor
+                        .extract_special(&file_name, metadata, 0)
+                        .context(PxarExtractContext::ExtractSocket)
                 } else {
                     Ok(())
                 }
@@ -342,6 +352,7 @@ where
                         "found regular file entry without contents in archive"
                     ))
                 }
+                .context(PxarExtractContext::ExtractFile)
             }
             (false, _) => Ok(()), // skip this
         };
@@ -354,6 +365,75 @@ where
     }
 }
 
+/// Provides additional [context][C] for [`anyhow::Error`]s that are returned
+/// while traversing an [`ExtractorIter`]. The [`PxarExtractContext`] can then
+/// be accessed [via `anyhow`'s facilities][A] and may aid during error handling.
+///
+///
+/// # Example
+///
+/// ```
+/// # use anyhow::{anyhow, Error};
+/// # use std::io;
+/// # use pbs_client::pxar::PxarExtractContext;
+///
+/// let err = anyhow!("oh noes!").context(PxarExtractContext::ExtractFile);
+///
+/// if let Some(ctx) = err.downcast_ref::<PxarExtractContext>() {
+///     match ctx {
+///         PxarExtractContext::ExtractFile => {
+///             // Conditionally handle the underlying error by type
+///             if let Some(io_err) = err.downcast_ref::<io::Error>() {
+///                 // ...
+///             };
+///         },
+///         PxarExtractContext::ExtractSocket => {
+///             // ...
+///         },
+///         // ...
+/// #        _ => (),
+///     }
+/// }
+/// ```
+///
+/// [A]: anyhow::Error
+/// [C]: anyhow::Context
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum PxarExtractContext {
+    EnterDirectory,
+    LeaveDirectory,
+    ExtractSymlink,
+    ExtractHardlink,
+    ExtractDevice,
+    ExtractFifo,
+    ExtractSocket,
+    ExtractFile,
+}
+
+impl PxarExtractContext {
+    #[inline]
+    pub fn as_str(&self) -> &'static str {
+        use PxarExtractContext::*;
+
+        match *self {
+            EnterDirectory => "failed to enter directory",
+            LeaveDirectory => "failed to leave directory",
+            ExtractSymlink => "failed to extract symlink",
+            ExtractHardlink => "failed to extract hardlink",
+            ExtractDevice => "failed to extract device",
+            ExtractFifo => "failed to extract named pipe",
+            ExtractSocket => "failed to extract unix socket",
+            ExtractFile => "failed to extract file",
+        }
+    }
+}
+
+impl std::fmt::Display for PxarExtractContext {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
 /// Common state for file extraction.
 pub struct Extractor {
     feature_flags: Flags,
diff --git a/pbs-client/src/pxar/mod.rs b/pbs-client/src/pxar/mod.rs
index a158101d..b042717d 100644
--- a/pbs-client/src/pxar/mod.rs
+++ b/pbs-client/src/pxar/mod.rs
@@ -59,7 +59,7 @@ pub use flags::Flags;
 pub use create::{create_archive, PxarCreateOptions};
 pub use extract::{
     create_tar, create_zip, extract_archive, extract_sub_dir, extract_sub_dir_seq, ErrorHandler,
-    PxarExtractOptions,
+    PxarExtractContext, PxarExtractOptions,
 };
 
 /// The format requires to build sorted directory lookup tables in
-- 
2.39.2

[pbs-devel] [PATCH v2 proxmox-backup 4/5] proxmox-backup-client: restore: add 'ignore-extract-device-errors' flag

[Max Carrara]

If this flag is provided, any errors that occur during the extraction
of a device node are silently ignored.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---
 Changes v1 --> v2:
  * Remove unnecessary "future-proofing" that merges many error handlers into one

 proxmox-backup-client/src/main.rs | 32 ++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
index 1a6114b1..c7f90109 100644
--- a/proxmox-backup-client/src/main.rs
+++ b/proxmox-backup-client/src/main.rs
@@ -30,6 +30,7 @@ use pbs_api_types::{
     BACKUP_TYPE_SCHEMA, TRAFFIC_CONTROL_BURST_SCHEMA, TRAFFIC_CONTROL_RATE_SCHEMA,
 };
 use pbs_client::catalog_shell::Shell;
+use pbs_client::pxar::ErrorHandler as PxarErrorHandler;
 use pbs_client::tools::{
     complete_archive_name, complete_auth_id, complete_backup_group, complete_backup_snapshot,
     complete_backup_source, complete_chunk_size, complete_group_or_snapshot,
@@ -1233,6 +1234,12 @@ We do not extract '.pxar' archives when writing to standard output.
                 optional: true,
                 default: false,
             },
+            "ignore-extract-device-errors": {
+                type: Boolean,
+                description: "ignore errors that occur during device node extraction",
+                optional: true,
+                default: false,
+            }
         }
     }
 )]
@@ -1245,6 +1252,7 @@ async fn restore(
     ignore_ownership: bool,
     ignore_permissions: bool,
     overwrite: bool,
+    ignore_extract_device_errors: bool,
 ) -> Result<Value, Error> {
     let repo = extract_repository_from_value(&param)?;
 
@@ -1365,12 +1373,34 @@ async fn restore(
 
         let mut reader = BufferedDynamicReader::new(index, chunk_reader);
 
+        let on_error = if ignore_extract_device_errors {
+            let handler: PxarErrorHandler = Box::new(move |err: Error| {
+                use pbs_client::pxar::PxarExtractContext;
+
+                let ctx = err.downcast_ref::<PxarExtractContext>();
+
+                if ctx.is_none() {
+                    return Err(err);
+                }
+
+                if matches!(ctx.unwrap(), PxarExtractContext::ExtractDevice) {
+                    return Ok(());
+                }
+
+                Err(err)
+            });
+
+            Some(handler)
+        } else {
+            None
+        };
+
         let options = pbs_client::pxar::PxarExtractOptions {
             match_list: &[],
             extract_match_default: true,
             allow_existing_dirs,
             overwrite,
-            on_error: None,
+            on_error,
         };
 
         let mut feature_flags = pbs_client::pxar::Flags::DEFAULT;
-- 
2.39.2

[pbs-devel] [PATCH v2 pve-container 5/5] fix #3460: restore: honor '--ignore-unpack-errors' flag for pbs

[Max Carrara]

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---
 NOTE: This patch requires a version bump+upload of proxmox-backup-client as well
       as bumping the versioned dependency in debian/control

 Changes v1 --> v2:
  * None

 src/PVE/LXC/Create.pm | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/PVE/LXC/Create.pm b/src/PVE/LXC/Create.pm
index 981f92d..f4c3220 100644
--- a/src/PVE/LXC/Create.pm
+++ b/src/PVE/LXC/Create.pm
@@ -116,6 +116,10 @@ sub restore_proxmox_backup_archive {
     my $cmd = "restore";
     my $param = [$name, "root.pxar", $rootdir, '--allow-existing-dirs'];
 
+    if ($no_unpack_error) {
+        push(@$param, '--ignore-extract-device-errors');
+    }
+
     PVE::Storage::PBSPlugin::run_raw_client_cmd(
 	$scfg, $storeid, $cmd, $param, userns_cmd => $userns_cmd);
 
-- 
2.39.2

Re: [pbs-devel] [PATCH v2 proxmox-backup 4/5] proxmox-backup-client: restore: add 'ignore-extract-device-errors' flag

[Christoph Heiss]

On Wed, Jul 12, 2023 at 03:00:43PM +0200, Max Carrara wrote:
> If this flag is provided, any errors that occur during the extraction
> of a device node are silently ignored.
>
> Signed-off-by: Max Carrara <m.carrara@proxmox.com>
> ---
>  Changes v1 --> v2:
>   * Remove unnecessary "future-proofing" that merges many error handlers into one
>
>  proxmox-backup-client/src/main.rs | 32 ++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
> index 1a6114b1..c7f90109 100644
> --- a/proxmox-backup-client/src/main.rs
> +++ b/proxmox-backup-client/src/main.rs
>
> [..]
>
> @@ -1245,6 +1252,7 @@ async fn restore(
>      ignore_ownership: bool,
>      ignore_permissions: bool,
>      overwrite: bool,
> +    ignore_extract_device_errors: bool,
>  ) -> Result<Value, Error> {
>      let repo = extract_repository_from_value(&param)?;
>
> @@ -1365,12 +1373,34 @@ async fn restore(
>
>          let mut reader = BufferedDynamicReader::new(index, chunk_reader);
>
> +        let on_error = if ignore_extract_device_errors {
> +            let handler: PxarErrorHandler = Box::new(move |err: Error| {
> +                use pbs_client::pxar::PxarExtractContext;
> +
> +                let ctx = err.downcast_ref::<PxarExtractContext>();
> +
> +                if ctx.is_none() {
> +                    return Err(err);
> +                }
> +
> +                if matches!(ctx.unwrap(), PxarExtractContext::ExtractDevice) {
> +                    return Ok(());
> +                }
> +
> +                Err(err)
> +            });
> +
> +            Some(handler)
Couldn't this be a lot simpler written as:

Some(Box::new(move |err: Error| {
    use pbs_client::pxar::PxarExtractContext;

    match err.downcast_ref::<PxarExtractContext>() {
	Some(PxarExtractContext::ExtractDevice) => Ok(()),
	_ => Err(err),
    }
}))

(untested; just off the top of my head)

> +        } else {
> +            None
> +        };
> +
>          let options = pbs_client::pxar::PxarExtractOptions {
>              match_list: &[],
>              extract_match_default: true,
>              allow_existing_dirs,
>              overwrite,
> -            on_error: None,
> +            on_error,
>          };
>
>          let mut feature_flags = pbs_client::pxar::Flags::DEFAULT;
> --
> 2.39.2
>
>
>
> _______________________________________________
> pbs-devel mailing list
> pbs-devel@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel
>
>

Re: [pbs-devel] [PATCH v2 proxmox-backup 4/5] proxmox-backup-client: restore: add 'ignore-extract-device-errors' flag

[Max Carrara]

On 7/13/23 09:52, Christoph Heiss wrote:
> 
> On Wed, Jul 12, 2023 at 03:00:43PM +0200, Max Carrara wrote:
>> If this flag is provided, any errors that occur during the extraction
>> of a device node are silently ignored.
>>
>> Signed-off-by: Max Carrara <m.carrara@proxmox.com>
>> ---
>>  Changes v1 --> v2:
>>   * Remove unnecessary "future-proofing" that merges many error handlers into one
>>
>>  proxmox-backup-client/src/main.rs | 32 ++++++++++++++++++++++++++++++-
>>  1 file changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
>> index 1a6114b1..c7f90109 100644
>> --- a/proxmox-backup-client/src/main.rs
>> +++ b/proxmox-backup-client/src/main.rs
>>
>> [..]
>>
>> @@ -1245,6 +1252,7 @@ async fn restore(
>>      ignore_ownership: bool,
>>      ignore_permissions: bool,
>>      overwrite: bool,
>> +    ignore_extract_device_errors: bool,
>>  ) -> Result<Value, Error> {
>>      let repo = extract_repository_from_value(&param)?;
>>
>> @@ -1365,12 +1373,34 @@ async fn restore(
>>
>>          let mut reader = BufferedDynamicReader::new(index, chunk_reader);
>>
>> +        let on_error = if ignore_extract_device_errors {
>> +            let handler: PxarErrorHandler = Box::new(move |err: Error| {
>> +                use pbs_client::pxar::PxarExtractContext;
>> +
>> +                let ctx = err.downcast_ref::<PxarExtractContext>();
>> +
>> +                if ctx.is_none() {
>> +                    return Err(err);
>> +                }
>> +
>> +                if matches!(ctx.unwrap(), PxarExtractContext::ExtractDevice) {
>> +                    return Ok(());
>> +                }
>> +
>> +                Err(err)
>> +            });
>> +
>> +            Some(handler)
> Couldn't this be a lot simpler written as:
> 
> Some(Box::new(move |err: Error| {
>     use pbs_client::pxar::PxarExtractContext;
> 
>     match err.downcast_ref::<PxarExtractContext>() {
> 	Some(PxarExtractContext::ExtractDevice) => Ok(()),
> 	_ => Err(err),
>     }
> }))
> 
> (untested; just off the top of my head)
> 

Oh, true! I missed that one. I'll see what else turns up before
sending in another series though.

>> +        } else {
>> +            None
>> +        };
>> +
>>          let options = pbs_client::pxar::PxarExtractOptions {
>>              match_list: &[],
>>              extract_match_default: true,
>>              allow_existing_dirs,
>>              overwrite,
>> -            on_error: None,
>> +            on_error,
>>          };
>>
>>          let mut feature_flags = pbs_client::pxar::Flags::DEFAULT;
>> --
>> 2.39.2
>>
>>
>>
>> _______________________________________________
>> pbs-devel mailing list
>> pbs-devel@lists.proxmox.com
>> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel
>>
>>