Move the ELF bindings to linux-raw-sys. (#817)

There are uses for the ELF bindings outside of this crate, so move them
into the linux-raw-sys crate.

Author: sunfishcode

Cargo.toml

@@ -36,7 +36,7 @@ once_cell = { version = "1.5.2", optional = true }
 # libc backend can be selected via adding `--cfg=rustix_use_libc` to
 # `RUSTFLAGS` or enabling the `use-libc` cargo feature.
 [target.'cfg(all(not(rustix_use_libc), not(miri), target_os = "linux", target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "riscv64", all(rustix_use_experimental_asm, target_arch = "powerpc64"), all(rustix_use_experimental_asm, target_arch = "mips"), all(rustix_use_experimental_asm, target_arch = "mips32r6"), all(rustix_use_experimental_asm, target_arch = "mips64"), all(rustix_use_experimental_asm, target_arch = "mips64r6"), target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64"))))'.dependencies]
-linux-raw-sys = { version = "0.4.3", default-features = false, features = ["general", "errno", "ioctl", "no_std"] }
+linux-raw-sys = { version = "0.4.7", default-features = false, features = ["general", "errno", "ioctl", "no_std", "elf"] }
 libc_errno = { package = "errno", version = "0.3.1", default-features = false, optional = true }
 libc = { version = "0.2.147", default-features = false, features = ["extra_traits"], optional = true }
 

src/backend/linux_raw/elf.rs

@@ -17,13 +17,6 @@
 #[macro_use]
 mod arch;
 mod conv;
-#[cfg(any(
-    feature = "param",
-    feature = "runtime",
-    feature = "time",
-    target_arch = "x86"
-))]
-mod elf;
 mod reg;
 #[cfg(any(feature = "time", target_arch = "x86"))]
 mod vdso;

src/backend/linux_raw/mod.rs

@@ -6,19 +6,18 @@
 #![allow(unsafe_code)]
 
 use crate::backend::c;
-use crate::backend::elf::*;
 use crate::fd::OwnedFd;
 #[cfg(feature = "param")]
 use crate::ffi::CStr;
 use crate::fs::{Mode, OFlags};
 use crate::utils::{as_ptr, check_raw_pointer};
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
-use core::ffi::c_void;
 use core::mem::size_of;
 use core::ptr::{null_mut, read_unaligned, NonNull};
 use core::sync::atomic::Ordering::Relaxed;
 use core::sync::atomic::{AtomicPtr, AtomicUsize};
+use linux_raw_sys::elf::*;
 use linux_raw_sys::general::{
     AT_BASE, AT_CLKTCK, AT_EXECFN, AT_HWCAP, AT_HWCAP2, AT_NULL, AT_PAGESZ, AT_SYSINFO_EHDR,
 };
@@ -382,19 +381,6 @@ unsafe fn check_elf_base(base: *const Elf_Ehdr) -> Option<NonNull<Elf_Ehdr>> {
     Some(NonNull::new_unchecked(as_ptr(hdr) as *mut _))
 }
 
-// ELF ABI
-
-#[repr(C)]
-#[derive(Copy, Clone)]
-struct Elf_auxv_t {
-    a_type: usize,
-
-    // Some of the values in the auxv array are pointers, so we make `a_val` a
-    // pointer, in order to preserve their provenance. For the values which are
-    // integers, we cast this to `usize`.
-    a_val: *const c_void,
-}
-
 // Aux reading utilities
 
 // Read auxv records from an array in memory.

src/backend/linux_raw/param/auxv.rs

@@ -6,12 +6,12 @@
 #![allow(unsafe_code)]
 
 use crate::backend::c;
-use crate::backend::elf::*;
 #[cfg(feature = "param")]
 use crate::ffi::CStr;
 use core::ffi::c_void;
 use core::ptr::{null_mut, read, NonNull};
 use core::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
+use linux_raw_sys::elf::*;
 use linux_raw_sys::general::{
     AT_CLKTCK, AT_EXECFN, AT_HWCAP, AT_HWCAP2, AT_NULL, AT_PAGESZ, AT_SYSINFO_EHDR,
 };
@@ -147,16 +147,3 @@ unsafe fn init_from_auxp(mut auxp: *const Elf_auxv_t) {
         auxp = auxp.add(1);
     }
 }
-
-// ELF ABI
-
-#[repr(C)]
-#[derive(Copy, Clone)]
-struct Elf_auxv_t {
-    a_type: usize,
-
-    // Some of the values in the auxv array are pointers, so we make `a_val` a
-    // pointer, in order to preserve their provenance. For the values which are
-    // integers, we cast this to `usize`.
-    a_val: *mut c_void,
-}

src/backend/linux_raw/param/init.rs

@@ -6,11 +6,11 @@
 #![allow(unsafe_code)]
 
 use crate::backend::c;
-use crate::backend::elf::*;
 #[cfg(feature = "param")]
 use crate::ffi::CStr;
 #[cfg(not(feature = "runtime"))]
 use core::ptr::null;
+use linux_raw_sys::elf::*;
 
 // `getauxval` wasn't supported in glibc until 2.16. Also this lets us use
 // `*mut` as the return type to preserve strict provenance.

src/backend/linux_raw/param/libc_auxv.rs

@@ -7,9 +7,9 @@
 #![allow(unsafe_code)]
 
 use crate::backend::c;
-use crate::backend::elf::*;
 use crate::backend::param::auxv::exe_phdrs;
 use core::ptr::{null, NonNull};
+use linux_raw_sys::elf::*;
 
 /// For use with [`set_thread_area`].
 ///

src/backend/linux_raw/runtime/tls.rs

@@ -13,12 +13,12 @@
 #![allow(unsafe_code)]
 
 use super::c;
-use super::elf::*;
 use crate::ffi::CStr;
 use crate::utils::check_raw_pointer;
 use core::ffi::c_void;
 use core::mem::size_of;
 use core::ptr::{null, null_mut};
+use linux_raw_sys::elf::*;
 
 pub(super) struct Vdso {
     // Load information
@@ -143,28 +143,31 @@ fn init_from_sysinfo_ehdr() -> Option<Vdso> {
             match d.d_tag {
                 DT_STRTAB => {
                     vdso.symstrings =
-                        check_raw_pointer::<u8>(vdso.addr_from_elf(d.d_val)? as *mut _)?.as_ptr();
+                        check_raw_pointer::<u8>(vdso.addr_from_elf(d.d_un.d_ptr)? as *mut _)?
+                            .as_ptr();
                 }
                 DT_SYMTAB => {
                     vdso.symtab =
-                        check_raw_pointer::<Elf_Sym>(vdso.addr_from_elf(d.d_val)? as *mut _)?
+                        check_raw_pointer::<Elf_Sym>(vdso.addr_from_elf(d.d_un.d_ptr)? as *mut _)?
                             .as_ptr();
                 }
                 DT_HASH => {
-                    hash =
-                        check_raw_pointer::<u32>(vdso.addr_from_elf(d.d_val)? as *mut _)?.as_ptr();
+                    hash = check_raw_pointer::<u32>(vdso.addr_from_elf(d.d_un.d_ptr)? as *mut _)?
+                        .as_ptr();
                 }
                 DT_VERSYM => {
                     vdso.versym =
-                        check_raw_pointer::<u16>(vdso.addr_from_elf(d.d_val)? as *mut _)?.as_ptr();
+                        check_raw_pointer::<u16>(vdso.addr_from_elf(d.d_un.d_ptr)? as *mut _)?
+                            .as_ptr();
                 }
                 DT_VERDEF => {
-                    vdso.verdef =
-                        check_raw_pointer::<Elf_Verdef>(vdso.addr_from_elf(d.d_val)? as *mut _)?
-                            .as_ptr();
+                    vdso.verdef = check_raw_pointer::<Elf_Verdef>(
+                        vdso.addr_from_elf(d.d_un.d_ptr)? as *mut _,
+                    )?
+                    .as_ptr();
                 }
                 DT_SYMENT => {
-                    if d.d_val != size_of::<Elf_Sym>() {
+                    if d.d_un.d_val != size_of::<Elf_Sym>() as _ {
                         return None; // Failed
                     }
                 }