From 641204425e586ce2bf74dfc6b480438c4470b138 Mon Sep 17 00:00:00 2001
From: Astro <astro@spaceboyz.net>
Date: Mon, 27 Jul 2020 01:58:42 +0200
Subject: [PATCH] dyld: obtain EXIDX offsets from section headers

Gitea issue #16
---
 src/libdyld/src/file.rs |  8 ++++++++
 src/libdyld/src/lib.rs  | 20 ++++++++++++++------
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/libdyld/src/file.rs b/src/libdyld/src/file.rs
index accebcc3..1c149dc6 100644
--- a/src/libdyld/src/file.rs
+++ b/src/libdyld/src/file.rs
@@ -56,6 +56,14 @@ impl<'a> File<'a> {
         })
     }
 
+    pub fn section_headers<'b>(&'b self) -> impl Iterator<Item = Option<Elf32_Shdr>> + 'b
+    {
+        (0..self.ehdr.e_shnum).map(move |i| {
+            let shdr_off = self.ehdr.e_shoff as usize + mem::size_of::<Elf32_Shdr>() * i as usize;
+            self.read_unaligned::<Elf32_Shdr>(shdr_off)
+        })
+    }
+
     pub fn dyn_header_vaddr(&self) -> Option<Range<usize>> {
         self.program_headers()
             .filter_map(|phdr| phdr)
diff --git a/src/libdyld/src/lib.rs b/src/libdyld/src/lib.rs
index 15f69116..4285849b 100644
--- a/src/libdyld/src/lib.rs
+++ b/src/libdyld/src/lib.rs
@@ -222,13 +222,21 @@ pub fn load(
                     .ok_or("program header requests an out of bounds load (in target)")?;
                 dst.copy_from_slice(src);
             }
-            PT_ARM_EXIDX => {
-                let range = image.get(phdr.p_vaddr as usize..
-                    (phdr.p_vaddr + phdr.p_filesz) as usize)
-                    .ok_or("program header requests and out of bounds load (in target)")?;
+            _ => {}
+        }
+    }
+
+    // Obtain EXIDX
+    for shdr in file.section_headers() {
+        let shdr = shdr.ok_or("cannot read section header")?;
+        match shdr.sh_type as usize {
+            SHT_ARM_EXIDX => {
+                let slice = image.get(shdr.sh_addr as usize..
+                                      (shdr.sh_addr + shdr.sh_size) as usize)
+                    .ok_or("section header requests an out of bounds load (in target)")?;
                 unsafe {
-                    KERNEL_EXIDX_START = range.as_ptr() as u32;
-                    KERNEL_EXIDX_END = range.as_ptr().add(range.len()) as u32;
+                    KERNEL_EXIDX_START = slice.as_ptr() as u32;
+                    KERNEL_EXIDX_END = slice.as_ptr().add(slice.len()) as u32;
                 }
             }
             _ => {}