treewide: refactor read_file and mkdir

src/main.rs

@@ -5,7 +5,7 @@ use std::env;
 use std::env::current_exe;
 use std::ffi::CString;
 use std::fmt::Write as _;
-use std::fs::{create_dir, read_to_string, File, OpenOptions};
+use std::fs::{File, OpenOptions};
 use std::io;
 use std::io::Write as _;
 use std::os::fd::{AsFd, AsRawFd, RawFd};
@@ -25,6 +25,7 @@ use nix::unistd::{chdir, chroot, dup2, execv, unlink};
 use systemd::{mount_systemd, shutdown};
 #[cfg(feature = "usb9pfs")]
 use usbg_9pfs::prepare_9pfs_gadget;
+use util::read_file;
 
 mod cmdline;
 #[cfg(feature = "dmverity")]
@@ -34,22 +35,10 @@ mod mount;
 mod systemd;
 #[cfg(feature = "usb9pfs")]
 mod usbg_9pfs;
+mod util;
 
 type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
 
-pub fn mkdir(dir: &str) -> Result<()> {
-    if let Err(e) = create_dir(dir) {
-        if e.kind() != io::ErrorKind::AlreadyExists {
-            return Err(format!("Failed to create {dir}: {e}",).into());
-        }
-    }
-    Ok(())
-}
-
-fn read_file(filename: &str) -> std::result::Result<String, String> {
-    read_to_string(filename).map_err(|e| format!("Failed to read {filename}: {e}"))
-}
-
 /*
  * Setup stdout/stderr. The kernel will create /dev/console in the
  * initramfs, so we can use that.

src/mount.rs

@@ -7,7 +7,8 @@ use log::debug;
 use nix::mount::{mount, MsFlags};
 
 use crate::cmdline::CmdlineOptions;
-use crate::{mkdir, Result};
+use crate::util::mkdir;
+use crate::Result;
 
 pub fn do_mount(
     src: Option<&str>,

src/systemd.rs

@@ -10,7 +10,8 @@ use nix::sys::reboot::{reboot, RebootMode};
 
 use crate::cmdline::CmdlineOptions;
 use crate::mount::do_mount;
-use crate::{mkdir, Result};
+use crate::util::mkdir;
+use crate::Result;
 
 pub fn mount_systemd(options: &mut CmdlineOptions) -> Result<()> {
     do_mount(

src/usbg_9pfs.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
-use std::fs::{read_dir, write};
+use std::fs::read_dir;
 use std::os::unix::ffi::OsStrExt;
 use std::os::unix::fs::symlink;
 use std::{thread, time};
@@ -9,11 +9,8 @@ use log::debug;
 
 use crate::cmdline::CmdlineOptions;
 use crate::mount::mount_apivfs;
-use crate::{mkdir, Result};
-
-fn write_file<C: AsRef<[u8]>>(path: &str, content: C) -> Result<()> {
-    write(path, content).map_err(|e| format!("Failed to write to {path}: {e}").into())
-}
+use crate::util::{mkdir, write_file};
+use crate::Result;
 
 fn setup_9pfs_gadget(device: &String) -> Result<()> {
     debug!("Initializing USB 9pfs gadget ...");

src/util.rs

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+use std::{
+    fs::{create_dir_all, read_to_string, write},
+    path::Path,
+};
+
+use crate::Result;
+
+pub(crate) fn mkdir(dir: impl AsRef<Path>) -> Result<()> {
+    create_dir_all(dir.as_ref()).map_err(|e| {
+        format!(
+            "Failed to create directory {}: {e}",
+            dir.as_ref().to_string_lossy()
+        )
+        .into()
+    })
+}
+
+pub(crate) fn read_file(filename: impl AsRef<Path>) -> Result<String> {
+    read_to_string(filename.as_ref()).map_err(|e| {
+        format!(
+            "Failed to read {}: {e}",
+            filename.as_ref().to_string_lossy()
+        )
+        .into()
+    })
+}
+
+pub(crate) fn write_file<C: AsRef<[u8]>>(path: impl AsRef<Path>, content: C) -> Result<()> {
+    write(&path, content).map_err(|e| {
+        format!(
+            "Failed to write to {}: {e}",
+            path.as_ref().to_string_lossy()
+        )
+        .into()
+    })
+}