Add ntfs-shell, an example app to demonstrate all features of the crate.

ntfs-shell is a command-line shell to navigate through an NTFS filesystem.
It works read-only on image files, loopback devices, and raw partitions.
Very useful for debugging the crate, examining the structure of an NTFS filesystem, and extracting data from it.

3 files changed, 735 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 957eba8..70ccd5e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,13 @@ enumn = "0.1.3"
 memoffset = "0.6.4"
 strum_macros = "0.21.1"
 
+[dev-dependencies]
+anyhow = "1.0"
+
 [features]
 default = ["std"]
 std = ["arrayvec/std", "binread/std", "byteorder/std"]
+
+[[example]]
+name = "ntfs-shell"
+required-features = ["chrono"]
diff --git a/examples/ntfs-shell/main.rs b/examples/ntfs-shell/main.rs
new file mode 100644
index 0000000..06e7376
--- /dev/null
+++ b/examples/ntfs-shell/main.rs
@@ -0,0 +1,598 @@
+// Copyright 2021 Colin Finck <colin@reactos.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+mod sector_reader;
+
+use std::env;
+use std::fs::{File, OpenOptions};
+use std::io;
+use std::io::{BufReader, Read, Seek, Write};
+
+use anyhow::{anyhow, bail, Context, Result};
+use chrono::{DateTime, Utc};
+use ntfs::indexes::NtfsFileNameIndex;
+use ntfs::structured_values::{NtfsAttributeList, NtfsFileName, NtfsStandardInformation};
+use ntfs::value::NtfsValue;
+use ntfs::{Ntfs, NtfsAttribute, NtfsAttributeType, NtfsFile, NtfsReadSeek};
+
+use sector_reader::SectorReader;
+
+struct CommandInfo<'n, T>
+where
+    T: Read + Seek,
+{
+    current_directory: NtfsFile<'n>,
+    current_directory_string: String,
+    fs: T,
+}
+
+fn main() -> Result<()> {
+    let args: Vec<String> = env::args().collect();
+    if args.len() != 2 {
+        eprintln!("Usage: ntfs-shell FILESYSTEM");
+        eprintln!();
+        eprintln!("FILESYSTEM can be a path to any NTFS filesystem image.");
+        eprintln!("Under Windows and when run with administrative privileges, FILESYSTEM can also");
+        eprintln!("be the special path \\\\.\\C: to access the filesystem of the C: partition.");
+        bail!("Aborted");
+    }
+
+    let f = File::open(&args[1])?;
+    let sr = SectorReader::new(f, 512)?;
+    let mut fs = BufReader::new(sr);
+    let mut ntfs = Ntfs::new(&mut fs)?;
+    ntfs.read_upcase_table(&mut fs)?;
+    let current_directory = ntfs.root_directory(&mut fs)?;
+
+    let mut info = CommandInfo {
+        current_directory,
+        current_directory_string: String::new(),
+        fs,
+    };
+
+    println!("**********************************************************************");
+    println!("ntfs-shell - Demonstration of rust-ntfs");
+    println!("by Colin Finck <colin@reactos.org>");
+    println!("**********************************************************************");
+    println!();
+    println!("Opened \"{}\" read-only.", args[1]);
+    println!();
+
+    loop {
+        print!("ntfs-shell:\\{}> ", info.current_directory_string);
+        io::stdout().flush()?;
+
+        let mut input_string = String::new();
+        io::stdin().read_line(&mut input_string).unwrap();
+        if input_string.is_empty() {
+            // An empty `input_string` without even a newline looks like STDIN was closed.
+            break;
+        }
+
+        let input = input_string.trim();
+        let mid = input.find(' ').unwrap_or(input.len());
+        let (command, arg) = input.split_at(mid);
+        let arg = arg.trim_start();
+
+        let result = match command {
+            "attr" => attr(false, arg, &mut info),
+            "attr_runs" => attr(true, arg, &mut info),
+            "cd" => cd(arg, &mut info),
+            "dir" => dir(&mut info),
+            "exit" | "quit" => break,
+            "fileinfo" => fileinfo(arg, &mut info),
+            "fsinfo" => fsinfo(&mut info),
+            "get" => get(arg, &mut info),
+            "help" => help(arg),
+            "" => continue,
+            _ => Err(anyhow!(
+                "Invalid command \"{}\". Type \"help\" to get a list of all commands.",
+                command
+            )),
+        };
+        if let Err(e) = result {
+            eprintln!("Error: {:?}", e);
+        }
+    }
+
+    Ok(())
+}
+
+fn attr<T>(with_runs: bool, arg: &str, info: &mut CommandInfo<T>) -> Result<()>
+where
+    T: Read + Seek,
+{
+    let ntfs = info.current_directory.ntfs();
+    let file = parse_file_arg(arg, info)?;
+
+    println!("{:=<110}", "");
+    println!(
+        "{:<10} | {:<20} | {:<8} | {:<13} | {:<18} | {:<13} | {}",
+        "INSTANCE", "TYPE", "RESIDENT", "RECORD NUMBER", "START", "LENGTH", "NAME"
+    );
+    println!("{:=<110}", "");
+
+    let attributes = file.attributes_raw();
+    for attribute in attributes {
+        let ty = attribute.ty()?;
+
+        attr_print_attribute(
+            with_runs,
+            &attribute,
+            file.file_record_number(),
+            "● ",
+            "  ■ ",
+        )?;
+
+        if ty == NtfsAttributeType::AttributeList {
+            let list = attribute.structured_value::<_, NtfsAttributeList>(&mut info.fs)?;
+            let mut list_iter = list.iter();
+
+            while let Some(entry) = list_iter.next(&mut info.fs) {
+                let entry = entry?;
+
+                let entry_record_number = entry.base_file_reference().file_record_number();
+                if entry_record_number == file.file_record_number() {
+                    continue;
+                }
+
+                let entry_file = entry.to_file(ntfs, &mut info.fs)?;
+                let entry_attribute = entry.to_attribute(&entry_file)?;
+
+                attr_print_attribute(
+                    with_runs,
+                    &entry_attribute,
+                    entry_record_number,
+                    "  ○ ",
+                    "    □ ",
+                )?;
+            }
+        }
+    }
+
+    Ok(())
+}
+
+fn attr_print_attribute<'n>(
+    with_runs: bool,
+    attribute: &NtfsAttribute<'n, '_>,
+    record_number: u64,
+    attribute_prefix: &str,
+    data_run_prefix: &str,
+) -> Result<()> {
+    let instance = format!("{}{}", attribute_prefix, attribute.instance());
+    let ty = attribute.ty()?;
+    let resident = attribute.is_resident();
+    let start = attribute.position();
+    let length = attribute.value_length();
+    let name = attribute.name()?.to_string_lossy();
+
+    println!(
+        "{:<10} | {:<20} | {:<8} | {:#13x} | {:#18x} | {:>13} | \"{}\"",
+        instance, ty, resident, record_number, start, length, name
+    );
+
+    if with_runs {
+        if let NtfsValue::NonResidentAttribute(non_resident_value) = attribute.value()? {
+            for (i, data_run) in non_resident_value.data_runs().enumerate() {
+                let data_run = data_run?;
+                let instance = format!("{}{}", data_run_prefix, i);
+                let start = data_run.data_position().unwrap_or(0);
+                let length = data_run.len();
+
+                println!(
+                    "{:<10} | {:<20} | {:<8} | {:>13} | {:#18x} | {:>13} |",
+                    instance, "DataRun", "", "", start, length
+                );
+            }
+        }
+    }
+
+    Ok(())
+}
+
+fn cd<T>(arg: &str, info: &mut CommandInfo<T>) -> Result<()>
+where
+    T: Read + Seek,
+{
+    if arg.is_empty() {
+        return Ok(());
+    }
+
+    let ntfs = info.current_directory.ntfs();
+
+    if arg == ".." {
+        if info.current_directory_string.is_empty() {
+            return Ok(());
+        }
+
+        let file_name = info.current_directory.name(&mut info.fs)?;
+        let parent_ref = file_name.parent_directory_reference();
+        info.current_directory = parent_ref.to_file(ntfs, &mut info.fs)?;
+
+        let new_len = info.current_directory_string.rfind('\\').unwrap_or(0);
+        info.current_directory_string.truncate(new_len);
+    } else {
+        let index = info.current_directory.directory_index(&mut info.fs)?;
+        let mut finder = index.finder();
+        let maybe_entry = NtfsFileNameIndex::find(&mut finder, &ntfs, &mut info.fs, arg);
+
+        if maybe_entry.is_none() {
+            println!("Cannot find subdirectory \"{}\".", arg);
+            return Ok(());
+        }
+
+        let entry = maybe_entry.unwrap()?;
+        let file_name = entry
+            .key()
+            .expect("key must exist for a found index entry")?;
+
+        if !file_name.is_directory() {
+            println!("\"{}\" is not a directory.", arg);
+            return Ok(());
+        }
+
+        info.current_directory = entry.to_file(ntfs, &mut info.fs)?;
+
+        let file_name = info.current_directory.name(&mut info.fs)?;
+        if !info.current_directory_string.is_empty() {
+            info.current_directory_string += "\\";
+        }
+        info.current_directory_string += &file_name.name().to_string_lossy();
+    }
+
+    Ok(())
+}
+
+fn dir<T>(info: &mut CommandInfo<T>) -> Result<()>
+where
+    T: Read + Seek,
+{
+    let index = info.current_directory.directory_index(&mut info.fs)?;
+    let mut iter = index.iter();
+
+    while let Some(entry) = iter.next(&mut info.fs) {
+        let entry = entry?;
+        let file_name = entry
+            .key()
+            .expect("key must exist for a found index entry")?;
+
+        let prefix = if file_name.is_directory() {
+            "<DIR>"
+        } else {
+            ""
+        };
+        println!("{:5}  {}", prefix, file_name.name());
+    }
+
+    Ok(())
+}
+
+fn fileinfo<T>(arg: &str, info: &mut CommandInfo<T>) -> Result<()>
+where
+    T: Read + Seek,
+{
+    let file = parse_file_arg(arg, info)?;
+
+    println!("{:=^72}", " FILE RECORD ");
+    println!("{:34}{}", "Allocated Size:", file.allocated_size());
+    println!("{:34}{:#x}", "Byte Position:", file.position());
+    println!("{:34}{}", "Hard-Link Count:", file.hard_link_count());
+    println!("{:34}{}", "Is Directory:", file.is_directory());
+    println!("{:34}{:#x}", "Record Number:", file.file_record_number());
+    println!("{:34}{}", "Sequence Number:", file.sequence_number());
+    println!("{:34}{}", "Used Size:", file.used_size());
+
+    let mut attributes = file.attributes();
+    while let Some(attribute_item) = attributes.next(&mut info.fs) {
+        let attribute_item = attribute_item?;
+        let attribute = attribute_item.to_attribute();
+
+        match attribute.ty() {
+            Ok(NtfsAttributeType::StandardInformation) => fileinfo_std(attribute)?,
+            Ok(NtfsAttributeType::FileName) => fileinfo_filename(info, attribute)?,
+            Ok(NtfsAttributeType::Data) => fileinfo_data(attribute)?,
+            _ => continue,
+        }
+    }
+
+    Ok(())
+}
+
+fn fileinfo_std(attribute: NtfsAttribute) -> Result<()> {
+    println!();
+    println!("{:=^72}", " STANDARD INFORMATION ");
+
+    let info = attribute.resident_structured_value::<NtfsStandardInformation>()?;
+
+    println!("{:34}{:?}", "Attributes:", info.file_attributes());
+
+    let format = "%F %T UTC";
+    let atime = DateTime::<Utc>::from(info.access_time()).format(format);
+    let ctime = DateTime::<Utc>::from(info.creation_time()).format(format);
+    let mtime = DateTime::<Utc>::from(info.modification_time()).format(format);
+    let mmtime = DateTime::<Utc>::from(info.mft_record_modification_time()).format(format);
+    println!("{:34}{}", "Access Time:", atime);
+    println!("{:34}{}", "Creation Time:", ctime);
+    println!("{:34}{}", "Modification Time:", mtime);
+    println!("{:34}{}", "MFT Record Modification Time:", mmtime);
+
+    // NTFS 3.x extended information
+    let class_id = info
+        .class_id()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    let maximum_versions = info
+        .maximum_versions()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    let owner_id = info
+        .owner_id()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    let quota_charged = info
+        .quota_charged()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    let security_id = info
+        .security_id()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    let usn = info
+        .usn()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    let version = info
+        .version()
+        .map(|x| x.to_string())
+        .unwrap_or_else(|| "<NONE>".to_string());
+    println!("{:34}{}", "Class ID:", class_id);
+    println!("{:34}{}", "Maximum Versions:", maximum_versions);
+    println!("{:34}{}", "Owner ID:", owner_id);
+    println!("{:34}{}", "Quota Charged:", quota_charged);
+    println!("{:34}{}", "Security ID:", security_id);
+    println!("{:34}{}", "USN:", usn);
+    println!("{:34}{}", "Version:", version);
+
+    Ok(())
+}
+
+fn fileinfo_filename<T>(info: &mut CommandInfo<T>, attribute: NtfsAttribute) -> Result<()>
+where
+    T: Read + Seek,
+{
+    println!();
+    println!("{:=^72}", " FILE NAME ");
+
+    let file_name = attribute.structured_value::<_, NtfsFileName>(&mut info.fs)?;
+
+    println!("{:34}\"{}\"", "Name:", file_name.name().to_string_lossy());
+    println!("{:34}{:?}", "Namespace:", file_name.namespace());
+    println!(
+        "{:34}{:#x}",
+        "Parent Directory Record Number:",
+        file_name.parent_directory_reference().file_record_number()
+    );
+
+    Ok(())
+}
+
+fn fileinfo_data(attribute: NtfsAttribute) -> Result<()> {
+    println!();
+    println!("{:=^72}", " DATA STREAM ");
+
+    println!("{:34}\"{}\"", "Name:", attribute.name()?.to_string_lossy());
+    println!("{:34}{}", "Size:", attribute.value_length());
+
+    Ok(())
+}
+
+fn fsinfo<T>(info: &mut CommandInfo<T>) -> Result<()>
+where
+    T: Read + Seek,
+{
+    let ntfs = info.current_directory.ntfs();
+
+    println!("{:20}{}", "Cluster Size:", ntfs.cluster_size());
+    println!("{:20}{}", "File Record Size:", ntfs.file_record_size());
+    println!("{:20}{:#x}", "MFT Byte Position:", ntfs.mft_position());
+
+    let volume_info = ntfs.volume_info(&mut info.fs)?;
+    let ntfs_version = format!(
+        "{}.{}",
+        volume_info.major_version(),
+        volume_info.minor_version()
+    );
+    println!("{:20}{}", "NTFS Version:", ntfs_version);
+
+    println!("{:20}{}", "Sector Size:", ntfs.sector_size());
+    println!("{:20}{}", "Serial Number:", ntfs.serial_number());
+    println!("{:20}{}", "Size:", ntfs.size());
+
+    let volume_name = if let Some(Ok(volume_name)) = ntfs.volume_name(&mut info.fs) {
+        volume_name.name().to_string_lossy()
+    } else {
+        "<NONE>".to_string()
+    };
+    println!("{:20}{}", "Volume Name:", volume_name);
+
+    Ok(())
+}
+
+fn get<T>(arg: &str, info: &mut CommandInfo<T>) -> Result<()>
+where
+    T: Read + Seek,
+{
+    // Extract any specific $DATA stream name from the file.
+    let mid = arg.find(':').unwrap_or(arg.len());
+    let (file_name, data_stream_name) = arg.split_at(mid);
+
+    // Compose the output file name and try to create it.
+    // It must not yet exist, as we don't want to accidentally overwrite things.
+    let output_file_name = if data_stream_name.is_empty() {
+        file_name.to_string()
+    } else {
+        format!("{}_{}", file_name, data_stream_name)
+    };
+    let mut output_file = OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .open(&output_file_name)
+        .with_context(|| format!("Tried to open \"{}\" for writing", output_file_name))?;
+
+    // Open the desired file and find the $DATA attribute we are looking for.
+    let file = parse_file_arg(file_name, info)?;
+    let data_item = match file.data(&mut info.fs, data_stream_name) {
+        Some(data_item) => data_item,
+        None => {
+            println!(
+                "The file does not have a \"{}\" $DATA attribute.",
+                data_stream_name
+            );
+            return Ok(());
+        }
+    };
+    let data_item = data_item?;
+    let data_attribute = data_item.to_attribute();
+    let mut data_value = data_attribute.value()?;
+
+    println!(
+        "Saving {} bytes of data in \"{}\"...",
+        data_value.len(),
+        output_file_name
+    );
+    let mut buf = [0u8; 4096];
+
+    loop {
+        let bytes_read = data_value.read(&mut info.fs, &mut buf)?;
+        if bytes_read == 0 {
+            break;
+        }
+
+        output_file.write(&buf[..bytes_read])?;
+    }
+
+    Ok(())
+}
+
+fn help(arg: &str) -> Result<()> {
+    match arg {
+        "attr" => {
+            println!("Usage: attr FILE");
+            println!();
+            println!("Shows the structure of all NTFS attributes of a single file, not including their data runs.");
+            println!("Try \"attr_runs\" if you are also interested in data run information.");
+            help_file("attr");
+        }
+        "attr_runs" => {
+            println!("Usage: attr_runs FILE");
+            println!();
+            println!("Shows the structure of all NTFS attributes of a single file, including their data runs.");
+            println!("Try \"attr\" if you don't need the data run information.");
+            help_file("attr_runs");
+        }
+        "cd" => {
+            println!("Usage: cd SUBDIRECTORY");
+            println!();
+            println!("Changes the current directory to SUBDIRECTORY.");
+            println!("This implementation of \"cd\" only supports subdirectories of the current directory.");
+            println!("\"cd ..\" moves back into the parent directory.");
+        }
+        "dir" => {
+            println!("Usage: dir");
+            println!();
+            println!("Lists filenames in the current directory (like \"ls\" on UNIX systems).");
+            println!("No additional parameters are supported.");
+            println!("Try \"fileinfo\" to get additional information about a single file.");
+        }
+        "fileinfo" => {
+            println!("Usage: fileinfo FILE");
+            println!();
+            println!("Shows information about a single file (by parsing its NTFS attributes).");
+            help_file("fileinfo");
+        }
+        "get" => {
+            println!("Usage:");
+            println!("  get FILE");
+            println!("  get FILE:STREAM");
+            println!();
+            println!("Copies the data of a single file from the NTFS filesystem to the current directory of your local filesystem.");
+            println!("Optionally, you can append a colon and a data stream name to copy a specific data stream of that file.");
+            println!();
+            println!("This command will fail if the file already exists in the current directory.");
+            help_file("get");
+        }
+        _ => {
+            println!("Available Commands:");
+            println!("  attr      - Show structure of NTFS attributes of a particular file");
+            println!("  attr_runs - Show structure of NTFS attributes of a particular file, including data runs");
+            println!("  cd        - Change the current directory");
+            println!("  dir       - Show files of the current directory");
+            println!("  exit      - Quit ntfs-shell");
+            println!("  fileinfo  - Show information about a particular file");
+            println!("  fsinfo    - Show general filesystem information");
+            println!("  get       - Copy a file from the NTFS filesystem");
+            println!("  help      - Show this help");
+            println!("  quit      - Quit ntfs-shell");
+            println!();
+            println!(
+                "You can also enter \"help COMMAND\" to get additional help about some commands."
+            );
+        }
+    }
+
+    Ok(())
+}
+
+fn help_file(command: &str) {
+    println!();
+    println!("FILE can have one of the following formats:");
+    println!("  ● A name of a file in the current directory.");
+    println!("    Enter the filename as is, including any spaces. Don't put it into additional quotation marks.");
+    println!("    Examples:");
+    println!("      ○ {} ntoskrnl.exe", command);
+    println!("      ○ {} File with spaces.exe", command);
+    println!("  ● A file record number anywhere on the filesystem.");
+    println!("    This is indicated through a leading slash (/). A hexadecimal file record number is indicated via 0x.");
+    println!("    Examples:");
+    println!("      ○ {} /5", command);
+    println!("      ○ {} /0xa299", command);
+}
+
+fn parse_file_arg<'n, T>(arg: &str, info: &mut CommandInfo<'n, T>) -> Result<NtfsFile<'n>>
+where
+    T: Read + Seek,
+{
+    if arg.is_empty() {
+        bail!("Missing argument!");
+    }
+
+    let ntfs = info.current_directory.ntfs();
+
+    if let Some(record_number_arg) = arg.strip_prefix("/") {
+        let record_number = match record_number_arg.strip_prefix("0x") {
+            Some(hex_record_number_arg) => u64::from_str_radix(hex_record_number_arg, 16),
+            None => u64::from_str_radix(record_number_arg, 10),
+        };
+
+        if let Ok(record_number) = record_number {
+            let file = ntfs.file(&mut info.fs, record_number)?;
+            Ok(file)
+        } else {
+            bail!(
+                "Cannot parse record number argument \"{}\"",
+                record_number_arg
+            )
+        }
+    } else {
+        let index = info.current_directory.directory_index(&mut info.fs)?;
+        let mut finder = index.finder();
+        if let Some(entry) = NtfsFileNameIndex::find(&mut finder, &ntfs, &mut info.fs, arg) {
+            let entry = entry?;
+            let file = entry.to_file(ntfs, &mut info.fs)?;
+            Ok(file)
+        } else {
+            bail!("No such file or directory \"{}\".", arg)
+        }
+    }
+}
diff --git a/examples/ntfs-shell/sector_reader.rs b/examples/ntfs-shell/sector_reader.rs
new file mode 100644
index 0000000..690d3ed
--- /dev/null
+++ b/examples/ntfs-shell/sector_reader.rs
@@ -0,0 +1,130 @@
+// Copyright 2021 Colin Finck <colin@reactos.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use std::io;
+use std::io::{Read, Seek, SeekFrom};
+
+/// `SectorReader` encapsulates any reader and only performs read and seek operations on it
+/// on boundaries of the given sector size.
+///
+/// This can be very useful for readers that only accept sector-sized reads (like reading
+/// from a raw partition on Windows).
+/// The sector size must be a power of two.
+///
+/// This reader does not keep any buffer.
+/// You are advised to encapsulate `SectorReader` in a buffered reader, as unbuffered reads of
+/// just a few bytes here and there are highly inefficient.
+pub struct SectorReader<R>
+where
+    R: Read + Seek,
+{
+    /// The inner reader stream.
+    inner: R,
+    /// The sector size set at creation.
+    sector_size: usize,
+    /// The current stream position as requested by the caller through `read` or `seek`.
+    /// The implementation will internally make sure to only read/seek on sector boundaries.
+    stream_position: u64,
+    /// This buffer is only part of the struct as a small performance optimization (keeping it allocated between reads).
+    temp_buf: Vec<u8>,
+}
+
+impl<R> SectorReader<R>
+where
+    R: Read + Seek,
+{
+    pub fn new(inner: R, sector_size: usize) -> io::Result<Self> {
+        if !sector_size.is_power_of_two() {
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                "sector_size is not a power of two",
+            ));
+        }
+
+        Ok(Self {
+            inner,
+            sector_size,
+            stream_position: 0,
+            temp_buf: Vec::new(),
+        })
+    }
+
+    fn align_down_to_sector_size(&self, n: u64) -> u64 {
+        n / self.sector_size as u64 * self.sector_size as u64
+    }
+
+    fn align_up_to_sector_size(&self, n: u64) -> u64 {
+        self.align_down_to_sector_size(n) + self.sector_size as u64
+    }
+}
+
+impl<R> Read for SectorReader<R>
+where
+    R: Read + Seek,
+{
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // We can only read from a sector boundary, and `self.stream_position` specifies the position where the
+        // caller thinks we are.
+        // Align down to a sector boundary to determine the position where we really are (see our `seek` implementation).
+        let aligned_position = self.align_down_to_sector_size(self.stream_position);
+
+        // We have to read more bytes now to make up for the alignment difference.
+        // We can also only read in multiples of the sector size, so align up to the next sector boundary.
+        let start = (self.stream_position - aligned_position) as usize;
+        let end = start + buf.len();
+        let aligned_bytes_to_read = self.align_up_to_sector_size(end as u64) as usize;
+
+        // Perform the sector-sized read and copy the actually requested bytes into the given buffer.
+        self.temp_buf.resize(aligned_bytes_to_read, 0);
+        self.inner.read_exact(&mut self.temp_buf)?;
+        buf.copy_from_slice(&self.temp_buf[start..end]);
+
+        // We are done.
+        self.stream_position += buf.len() as u64;
+        Ok(buf.len())
+    }
+}
+
+impl<R> Seek for SectorReader<R>
+where
+    R: Read + Seek,
+{
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let new_pos = match pos {
+            SeekFrom::Start(n) => Some(n),
+            SeekFrom::End(_n) => {
+                // This is unsupported, because it's not safely possible under Windows.
+                // We cannot seek to the end to determine the raw partition size.
+                // Which makes it impossible to set `self.stream_position`.
+                return Err(io::Error::new(
+                    io::ErrorKind::Other,
+                    "SeekFrom::End is unsupported for SectorReader",
+                ));
+            }
+            SeekFrom::Current(n) => {
+                if n >= 0 {
+                    self.stream_position.checked_add(n as u64)
+                } else {
+                    self.stream_position.checked_sub(n.wrapping_neg() as u64)
+                }
+            }
+        };
+
+        match new_pos {
+            Some(n) => {
+                // We can only seek on sector boundaries, so align down the requested seek position and seek to that.
+                let aligned_n = self.align_down_to_sector_size(n);
+                self.inner.seek(SeekFrom::Start(aligned_n))?;
+
+                // Make the caller believe that we seeked to the actually requested position.
+                // Our `read` implementation will cover the difference.
+                self.stream_position = n;
+                Ok(self.stream_position)
+            }
+            None => Err(io::Error::new(
+                io::ErrorKind::InvalidInput,
+                "invalid seek to a negative or overflowing position",
+            )),
+        }
+    }
+}