From de03566158887f33dc7234a5f0348eeb73cbd345 Mon Sep 17 00:00:00 2001
From: oddcoder <ahmedsoliman@oddcoder.com>
Date: Mon, 13 Apr 2020 12:39:51 +0200
Subject: [PATCH] Enable RTLD debugging protocol system-wide
This patch makes use of the data structures and functions impelemented
in the last patch to enable RTLD debugging protocol as per SVR4
---
src/ld_so/linker.rs | 53 ++++++++++++++++++++++++++++++++++++----
src/ld_so/start.rs | 6 +++++
src/platform/test/mod.rs | 9 ++-----
3 files changed, 56 insertions(+), 12 deletions(-)
diff --git a/src/ld_so/linker.rs b/src/ld_so/linker.rs
index 15c666711..818a5feb4 100644
--- a/src/ld_so/linker.rs
+++ b/src/ld_so/linker.rs
@@ -4,9 +4,16 @@ use alloc::{
string::{String, ToString},
vec::Vec,
};
-use core::{mem, ptr, slice};
+use core::{
+ mem::{size_of, transmute},
+ ptr, slice,
+};
use goblin::{
- elf::{program_header, reloc, sym, Elf},
+ elf::{
+ program_header,
+ r#dyn::{Dyn, DT_DEBUG},
+ reloc, sym, Elf,
+ },
error::{Error, Result},
};
@@ -19,6 +26,7 @@ use crate::{
};
use super::{
+ debug::{RTLDDebug, RTLDState, _dl_debug_state, _r_debug},
tcb::{Master, Tcb},
PAGE_SIZE,
};
@@ -197,6 +205,8 @@ impl Linker {
}
pub fn link(&mut self, primary_opt: Option<&str>, dso: Option<DSO>) -> Result<Option<usize>> {
+ unsafe { _r_debug.state = RTLDState::RT_ADD };
+ _dl_debug_state();
let elfs = {
let mut elfs = BTreeMap::new();
for (name, data) in self.objects.iter() {
@@ -219,7 +229,8 @@ impl Linker {
Some(some) => some,
None => continue,
};
-
+ // data for struct LinkMap
+ let mut l_ld = 0;
// Calculate virtual memory bounds
let bounds = {
let mut bounds_opt: Option<(usize, usize)> = None;
@@ -230,6 +241,9 @@ impl Linker {
((ph.p_memsz as usize + voff + PAGE_SIZE - 1) / PAGE_SIZE) * PAGE_SIZE;
match ph.p_type {
+ program_header::PT_DYNAMIC => {
+ l_ld = ph.p_vaddr;
+ }
program_header::PT_LOAD => {
if self.verbose {
println!(" load {:#x}, {:#x}: {:x?}", vaddr, vsize, ph);
@@ -284,6 +298,7 @@ impl Linker {
size,
sys_mman::PROT_READ | sys_mman::PROT_WRITE,
);
+ _r_debug.insert(addr as usize, &elf_name, addr + l_ld as usize);
slice::from_raw_parts_mut(addr as *mut u8, size)
} else {
let ptr = sys_mman::mmap(
@@ -301,6 +316,7 @@ impl Linker {
return Err(Error::Malformed(format!("failed to map {}", elf_name)));
}
ptr::write_bytes(ptr as *mut u8, 0, size);
+ _r_debug.insert(ptr as usize, &elf_name, ptr as usize + l_ld as usize);
slice::from_raw_parts_mut(ptr as *mut u8, size)
}
};
@@ -541,6 +557,32 @@ impl Linker {
}
}
+ // overwrite DT_DEBUG if exist in .dynamic section
+ for section in &elf.section_headers {
+ // we won't bother with half corrupted elfs.
+ let name = elf.shdr_strtab.get(section.sh_name).unwrap().unwrap();
+ if name != ".dynamic" {
+ continue;
+ }
+ let mmap = match self.mmaps.get_mut(*elf_name) {
+ Some(some) => some,
+ None => continue,
+ };
+ let dyn_start = section.sh_addr as usize;
+ let bytes: [u8; size_of::<Dyn>() / 2] =
+ unsafe { transmute((&_r_debug) as *const RTLDDebug as usize) };
+ if let Some(dynamic) = elf.dynamic.as_ref() {
+ let mut i = 0;
+ for entry in &dynamic.dyns {
+ if entry.d_tag == DT_DEBUG {
+ let start = dyn_start + i * size_of::<Dyn>() + size_of::<Dyn>() / 2;
+ mmap[start..start + size_of::<Dyn>() / 2].clone_from_slice(&bytes);
+ }
+ i += 1;
+ }
+ }
+ }
+
// Protect pages
for ph in elf.program_headers.iter() {
if ph.p_type == program_header::PT_LOAD {
@@ -629,7 +671,7 @@ impl Linker {
if rel.r_type == reloc::R_X86_64_IRELATIVE {
unsafe {
- let f: unsafe extern "C" fn() -> u64 = mem::transmute(b + a);
+ let f: unsafe extern "C" fn() -> u64 = transmute(b + a);
set_u64(f());
}
}
@@ -670,7 +712,8 @@ impl Linker {
}
}
}
-
+ unsafe { _r_debug.state = RTLDState::RT_CONSISTENT };
+ _dl_debug_state();
Ok(entry_opt)
}
}
diff --git a/src/ld_so/start.rs b/src/ld_so/start.rs
index 160754799..1d60b714f 100644
--- a/src/ld_so/start.rs
+++ b/src/ld_so/start.rs
@@ -7,6 +7,7 @@ use crate::{
};
use super::{
+ debug::_r_debug,
linker::{Linker, DSO},
tcb::Tcb,
};
@@ -130,6 +131,11 @@ pub extern "C" fn relibc_ld_so_start(sp: &'static mut Stack, ld_entry: usize) ->
true
};
+ // we might need global lock for this kind of stuff
+ unsafe {
+ _r_debug.r_ldbase = ld_entry;
+ }
+
// Some variables that will be overridden by environment and auxiliary vectors
let library_path = match envs.get("LD_LIBRARY_PATH") {
Some(lib_path) => lib_path,
diff --git a/src/platform/test/mod.rs b/src/platform/test/mod.rs
index 3ac5a1716..01889bb35 100644
--- a/src/platform/test/mod.rs
+++ b/src/platform/test/mod.rs
@@ -8,10 +8,7 @@ mod epoll;
#[test]
fn access() {
- use crate::header::{
- errno,
- unistd,
- };
+ use crate::header::{errno, unistd};
//TODO: create test files
assert_eq!(Sys::access(c_str!("not a file!"), unistd::F_OK), !0);
@@ -44,9 +41,7 @@ fn chdir() {
#[test]
fn clock_gettime() {
- use crate::header::{
- time
- };
+ use crate::header::time;
{
let mut timespec = time::timespec {
--
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