refactor(file): replace fdisk with gptman+mbrman (#154)

## Summary

Replace the fragile `fdisk`-based partition detection in
`get_partition_info()` with Rust-native `gptman` and `mbrman` crates.

**Changes:**
- Add `gptman` (GPT with CRC32 validation) and `mbrman` (MBR including
logical partitions) as dependencies
- Add `src/file/partition.rs` with `get_partition_data()` and `is_gpt()`
- Remove locale-sensitive `fdisk` shell invocation and regex parsing
- Remove `fdisk` from `package.metadata.deb` depends
- Change `PartitionInfo` fields from `String` to typed `u32`/`u64`

## Reason

The previous implementation spawned `fdisk -l` and parsed its text
output with regex — making it locale-sensitive, version-dependent, and
requiring `fdisk` as a runtime system dependency.

Additionally, a pre-existing bug was fixed: `PartitionInfo.end` held the
last sector (inclusive) from `fdisk` output and was passed directly as
`dd count=`, but `count` expects the number of sectors. For a partition
starting at sector 2048 and ending at 206847, this caused `dd` to copy
206847 sectors instead of the correct 204800.

**Fixed semantics:**
- GPT: `count = ending_lba - starting_lba + 1`
- MBR: `count = p.sectors` (already the sector count)

## Verification

- `cargo check` passes
- `cargo fmt -- --check` passes
- `cargo clippy -- -D warnings` passes
- Manually tested against GPT and MBR image files

---------

Signed-off-by: Harry Waschkeit <44188360+HarryWaschkeit@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: HarryWaschkeit

Cargo.lock

@@ -7,7 +7,7 @@ license = "MIT OR Apache-2.0"
 name = "omnect-cli"
 readme = "README.md"
 repository = "https://github.com/omnect/omnect-cli"
-version = "0.27.1"
+version = "0.27.2"
 
 [dependencies]
 actix-web = "4.11"
@@ -37,6 +37,8 @@ filemagic = { version = "0.13", default-features = false, features = [
     "pkg-config",
 ] }
 flate2 = { version = "1.1", default-features = false }
+gptman = { version = "1.1", default-features = false }
+mbrman = { version = "0.5", default-features = false }
 omnect-crypto = { git = "https://github.com/omnect/omnect-crypto.git", tag = "0.4.0" }
 keyring = { version = "3.6", default-features = false }
 libfs = { version = "0.9", default-features = false }
@@ -85,5 +87,5 @@ tar = "0.4"
 
 # metadata for building with cargo-deb (https://crates.io/crates/cargo-deb)
 [package.metadata.deb]
-depends = "bmap-tools, e2tools, fdisk, keychain, libc6 (>= 2.34), libmagic1, libssl3 (>= 3.0.0), mtools"
+depends = "bmap-tools, e2tools, keychain, libc6 (>= 2.34), libmagic1, libssl3 (>= 3.0.0), mtools"
 revision = ""

Cargo.toml

@@ -1,6 +1,5 @@
 use anyhow::{Context, Result};
 use log::{debug, warn};
-use regex::Regex;
 use std::collections::HashMap;
 use std::fmt::{self, Display};
 use std::fs;
@@ -22,9 +21,9 @@ pub enum Partition {
 
 #[derive(Debug)]
 struct PartitionInfo {
-    num: String,
-    start: String,
-    end: String,
+    num: u32,
+    start: u64,
+    count: u64,
 }
 
 impl Display for Partition {
@@ -184,23 +183,6 @@ macro_rules! try_exec_cmd {
     };
 }
 
-macro_rules! exec_cmd_with_output {
-    ($cmd:expr) => {{
-        let res = $cmd
-            .output()
-            .context(format!("{}: spawn {:?}", function_name!(), $cmd))?;
-
-        let output =
-            String::from_utf8(res.stdout).context(format!("{}: get output", function_name!()))?;
-
-        let output = output.trim();
-
-        debug!("{}: {:?}", function_name!(), $cmd);
-
-        output.to_string()
-    }};
-}
-
 pub fn copy_to_image(file_copy_params: &[FileCopyToParams], image_file: &Path) -> Result<()> {
     // we use the folder the image is located in
     // the caller is responsible to create a /tmp/ directory if needed
@@ -381,59 +363,39 @@ pub fn read_file_from_image(
 }
 
 fn get_partition_info(image_file: &str, partition: &Partition) -> Result<PartitionInfo> {
-    let mut fdisk = Command::new("fdisk");
-    fdisk
-        .arg("-l")
-        .arg("-o")
-        .arg("Device,Start,End")
-        .arg(image_file);
-    let fdisk_out = exec_cmd_with_output!(fdisk);
+    use crate::file::partition::{get_partition_data, is_gpt};
 
-    let partition_num = match partition {
+    let gpt =
+        is_gpt(image_file).context("get_partition_info: failed to detect partition table type")?;
+
+    let partition_num: u32 = match partition {
         Partition::boot => 1,
         Partition::rootA => 2,
-        p @ (Partition::factory | Partition::cert) => {
-            let re = Regex::new(r"Disklabel type: (\D{3})").unwrap();
-
-            let matches = re
-                .captures(&fdisk_out)
-                .context("get_partition_info: regex no matches found")?;
-            anyhow::ensure!(
-                matches.len() == 2,
-                "'get_partition_info: regex contains unexpected number of matches"
-            );
-
-            let partition_type = &matches[1];
-
-            debug!("partition type: {partition_type}");
-
-            match (p, partition_type) {
-                (Partition::factory, "gpt") => 4,
-                (Partition::factory, "dos") => 5,
-                (Partition::cert, "gpt") => 5,
-                (Partition::cert, "dos") => 6,
-                _ => anyhow::bail!("get_partition_info: unhandled partition type"),
+        Partition::factory => {
+            if gpt {
+                4
+            } else {
+                5
+            }
+        }
+        Partition::cert => {
+            if gpt {
+                5
+            } else {
+                6
             }
         }
     };
 
-    let re = Regex::new(format!(r"{image_file}{partition_num}\s+(\d+)\s+(\d+)").as_str())
-        .context("get_partition_info: failed to create regex")?;
-
-    let matches = re
-        .captures(&fdisk_out)
-        .context("get_partition_info: regex no matches found")?;
-    anyhow::ensure!(
-        matches.len() == 3,
-        "'get_partition_info: regex contains unexpected number of matches"
-    );
+    debug!("get_partition_info: partition={partition}, num={partition_num}, gpt={gpt}");
 
-    let partition_offset = (matches[1].to_string(), matches[2].to_string());
+    let data = get_partition_data(image_file, partition_num)
+        .with_context(|| format!("get_partition_info: failed to read partition {partition_num}"))?;
 
     let info = PartitionInfo {
-        num: partition_num.to_string(),
-        start: partition_offset.0,
-        end: partition_offset.1,
+        num: data.num,
+        start: data.start,
+        count: data.count,
     };
 
     debug!("get_partition_info: {:?}", info);
@@ -455,7 +417,7 @@ fn read_partition(
         .arg(format!("of={partition_file}"))
         .arg("bs=512")
         .arg(format!("skip={}", partition_info.start))
-        .arg(format!("count={}", partition_info.end))
+        .arg(format!("count={}", partition_info.count))
         .arg("conv=sparse")
         .arg("status=none");
     exec_cmd!(dd);
@@ -476,7 +438,7 @@ fn write_partition(
         .arg(format!("of={image_file}"))
         .arg("bs=512")
         .arg(format!("seek={}", partition_info.start))
-        .arg(format!("count={}", partition_info.end))
+        .arg(format!("count={}", partition_info.count))
         .arg("conv=notrunc,sparse")
         .arg("status=none");
     exec_cmd!(dd);

src/file/functions.rs

@@ -1,5 +1,6 @@
 pub mod compression;
 pub mod functions;
+mod partition;
 use super::validators::{
     device_update,
     identity::{IdentityConfig, IdentityType, validate_identity},