Revert "boost modify_cmdline speed by starting replacement at its offset on disk"

This reverts commit 0e3ad481706ff2f1e83487517415d251179ce3c3.

2 files changed, 3 insertions, 14 deletions

diff --git a/src/error.rs b/src/error.rs
index 97fa882..6f8e217 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -4,8 +4,6 @@ use thiserror::Error;
 
 #[derive(Debug, Error)]
 pub enum Error {
-    #[error("can't find cmdline (/cmdline.txt) on boot partition")]
-    NoCmdline,
     #[error("can't find disk device")]
     NoDiskDev,
     #[error("no private keys found in file")]
diff --git a/src/main.rs b/src/main.rs
index f72da42..89db44c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -279,21 +279,12 @@ where
 
 fn modify_cmdline(old: &str, new: &str) -> Result<()> {
     let boot = boot_dev()?;
-    let mut buf = fs::read(boot)?;
 
-    let cmdline_buf = fs::read("/boot/cmdline.txt")?;
-    let cmdline_offset = buf
-        .windows(cmdline_buf.len())
-        .position(|window| window == cmdline_buf)
-        .ok_or(Error::NoCmdline)?
-        / 512
-        + 1;
+    let mut cmdline = fs::read(boot)?;
+    replace_slice(&mut cmdline, old.as_bytes(), new.as_bytes());
+    fs::write(boot, cmdline)?;
 
-    replace_slice(&mut buf[cmdline_offset..], old.as_bytes(), new.as_bytes());
-
-    fs::write(boot, buf)?;
     nix::unistd::sync();
-
     Ok(())
 }