From 2c9b82513f1c2db46d23bf443f78ee5a11173d50 Mon Sep 17 00:00:00 2001
From: Urhengulas <johann.hemmann@code.berlin>
Date: Thu, 1 Apr 2021 23:36:45 +0200
Subject: [PATCH] `mod linking`

---
 src/linking.rs | 46 +++++++++++++++++++++++++++++++++++++++++++++
 src/main.rs    | 51 +++++---------------------------------------------
 2 files changed, 51 insertions(+), 46 deletions(-)
 create mode 100644 src/linking.rs

diff --git a/src/linking.rs b/src/linking.rs
new file mode 100644
index 0000000..0ab3578
--- /dev/null
+++ b/src/linking.rs
@@ -0,0 +1,46 @@
+use std::{path::Path, process::Command};
+
+use tempfile::TempDir;
+
+const EXIT_CODE_FAILURE: i32 = 1;
+// TODO make this configurable (via command-line flag or similar)
+const LINKER: &str = "rust-lld";
+
+pub fn link_normally(args: &[String]) -> Result<(), i32> {
+    let mut c = Command::new(LINKER);
+    c.args(args);
+    log::trace!("{:?}", c);
+
+    success_or_exitstatus(c)
+}
+
+pub fn link_again(
+    args: &[String],
+    current_dir: &Path,
+    new_origin: u64,
+    tempdir: &TempDir,
+) -> Result<(), i32> {
+    let mut c = Command::new(LINKER);
+    // add the current dir to the linker search path to include all unmodified scripts there
+    // HACK `-L` needs to go after `-flavor gnu`; position is currently hardcoded
+    c.args(&args[..2])
+        .arg("-L".to_string())
+        .arg(current_dir)
+        .args(&args[2..])
+        // we need to override `_stack_start` to make the stack start below fake RAM
+        .arg(format!("--defsym=_stack_start={}", new_origin))
+        // set working directory to temporary directory containing our new linker script
+        // this makes sure that it takes precedence over the original one
+        .current_dir(tempdir.path());
+    log::trace!("{:?}", c);
+
+    success_or_exitstatus(c)
+}
+
+fn success_or_exitstatus(mut c: Command) -> Result<(), i32> {
+    let status = c.status().unwrap();
+    if !status.success() {
+        return Err(status.code().unwrap_or(EXIT_CODE_FAILURE));
+    }
+    Ok(())
+}
diff --git a/src/main.rs b/src/main.rs
index d994b35..9ceb434 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,5 @@
+mod linking;
+
 use std::{
     borrow::Cow,
     env,
@@ -5,16 +7,12 @@ use std::{
     io::Write,
     ops::RangeInclusive,
     path::{Path, PathBuf},
-    process::{self, Command},
+    process,
 };
 
 use anyhow::anyhow;
 use object::{elf, Object as _, ObjectSection, SectionFlags};
-use tempfile::TempDir;
 
-const EXIT_CODE_FAILURE: i32 = 1;
-// TODO make this configurable (via command-line flag or similar)
-const LINKER: &str = "rust-lld";
 /// Stack Pointer alignment required by the ARM architecture
 const SP_ALIGN: u64 = 8;
 
@@ -25,7 +23,7 @@ fn main() -> anyhow::Result<()> {
     let args = env::args().skip(1).collect::<Vec<_>>();
 
     // if linking succeeds then linker scripts are well-formed; we'll rely on that in the parser
-    link_normally(&args).unwrap_or_else(|code| process::exit(code));
+    linking::link_normally(&args).unwrap_or_else(|code| process::exit(code));
 
     let current_dir = env::current_dir()?;
     let linker_scripts = get_linker_scripts(&args, &current_dir)?;
@@ -92,51 +90,12 @@ fn main() -> anyhow::Result<()> {
     // commit file to disk
     drop(new_linker_script);
 
-    link_again(&args, &current_dir, new_origin, &tempdir)
+    linking::link_again(&args, &current_dir, new_origin, &tempdir)
         .unwrap_or_else(|code| process::exit(code));
 
     Ok(())
 }
 
-fn link_normally(args: &[String]) -> Result<(), i32> {
-    let mut c = Command::new(LINKER);
-    c.args(args);
-    log::trace!("{:?}", c);
-
-    success_or_exitstatus(c)
-}
-
-fn link_again(
-    args: &[String],
-    current_dir: &Path,
-    new_origin: u64,
-    tempdir: &TempDir,
-) -> Result<(), i32> {
-    let mut c = Command::new(LINKER);
-    // add the current dir to the linker search path to include all unmodified scripts there
-    // HACK `-L` needs to go after `-flavor gnu`; position is currently hardcoded
-    c.args(&args[..2])
-        .arg("-L".to_string())
-        .arg(current_dir)
-        .args(&args[2..])
-        // we need to override `_stack_start` to make the stack start below fake RAM
-        .arg(format!("--defsym=_stack_start={}", new_origin))
-        // set working directory to temporary directory containing our new linker script
-        // this makes sure that it takes precedence over the original one
-        .current_dir(tempdir.path());
-    log::trace!("{:?}", c);
-
-    success_or_exitstatus(c)
-}
-
-fn success_or_exitstatus(mut c: Command) -> Result<(), i32> {
-    let status = c.status().unwrap();
-    if !status.success() {
-        return Err(status.code().unwrap_or(EXIT_CODE_FAILURE));
-    }
-    Ok(())
-}
-
 /// Returns `(used_ram_length, used_ram_align)`
 fn compute_span_of_ram_sections(ram_entry: MemoryEntry, object: object::File) -> (u64, u64) {
     let mut used_ram_start = u64::MAX;