From 7b29f6eb27fbba311ea659ce0be1ecaa83d7557f Mon Sep 17 00:00:00 2001
From: oddcoder <ahmedsoliman@oddcoder.com>
Date: Mon, 10 Aug 2020 23:43:24 +0200
Subject: [PATCH] Avoid relinking already linked libs
This patch avoids collecting symbols, resolving relocs if they are
already done (usually for example libc.so during a dlopen for another
libfoo.so). This patch is purely for performance boost.
---
src/ld_so/linker.rs | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/src/ld_so/linker.rs b/src/ld_so/linker.rs
index 34030513..5f7644bd 100644
--- a/src/ld_so/linker.rs
+++ b/src/ld_so/linker.rs
@@ -1,6 +1,6 @@
use alloc::{
boxed::Box,
- collections::BTreeMap,
+ collections::{BTreeMap, BTreeSet},
rc::Rc,
string::{String, ToString},
vec::Vec,
@@ -350,12 +350,15 @@ impl Linker {
) -> Result<Option<usize>> {
unsafe { _r_debug.state = RTLDState::RT_ADD };
_dl_debug_state();
+ let mut skip_list = BTreeSet::new();
let elfs = {
let mut elfs = BTreeMap::new();
for (name, data) in lib.objects.iter() {
// Skip already linked libraries
if !lib.mmaps.contains_key(&*name) && !self.root.mmaps.contains_key(&*name) {
elfs.insert(name.as_str(), Elf::parse(&data)?);
+ } else {
+ skip_list.insert(name.as_str());
}
}
elfs
@@ -365,6 +368,9 @@ impl Linker {
let mut tls_primary = 0;
let mut tls_size = 0;
for (elf_name, elf) in elfs.iter() {
+ if skip_list.contains(elf_name) {
+ continue;
+ }
if self.verbose {
println!("map {}", elf_name);
}
@@ -566,6 +572,9 @@ impl Linker {
});
let mut tls_ranges = BTreeMap::new();
for (elf_name, elf) in elfs.iter() {
+ if skip_list.contains(elf_name) {
+ continue;
+ }
let same_elf = if let Some(prog) = dso.as_ref() {
if prog.name == *elf_name {
true
@@ -690,6 +699,9 @@ impl Linker {
// Perform relocations, and protect pages
for (elf_name, elf) in elfs.iter() {
+ if skip_list.contains(elf_name) {
+ continue;
+ }
if self.verbose {
println!("link {}", elf_name);
}
@@ -888,6 +900,9 @@ impl Linker {
// Perform indirect relocations (necessary evil), gather entry point
let mut entry_opt = None;
for (elf_name, elf) in elfs.iter() {
+ if skip_list.contains(elf_name) {
+ continue;
+ }
let (_, mmap) = match lib.mmaps.get_mut(*elf_name) {
Some(some) => some,
None => continue,
--
GitLab