Add types and constants for working with Linux's ELF ABI. (#78)

* Add types and constants for working with Linux's ELF ABI.

* Remove Mips targets from CI.

Author: sunfishcode

.github/workflows/main.yml

@@ -53,8 +53,6 @@ jobs:
         aarch64-unknown-linux-musl
         powerpc64le-unknown-linux-gnu
         armv5te-unknown-linux-gnueabi
-        mipsel-unknown-linux-gnu
-        mips64el-unknown-linux-gnuabi64
     - run: cargo check --tests -vv
     - run: cargo check --tests -vv --target=x86_64-unknown-linux-musl
     - run: cargo check --tests -vv --target=x86_64-unknown-linux-gnux32
@@ -65,8 +63,6 @@ jobs:
     - run: cargo check --tests -vv --target=aarch64-unknown-linux-musl
     - run: cargo check --tests -vv --target=powerpc64le-unknown-linux-gnu
     - run: cargo check --tests -vv --target=armv5te-unknown-linux-gnueabi
-    - run: cargo check --tests -vv --target=mipsel-unknown-linux-gnu
-    - run: cargo check --tests -vv --target=mips64el-unknown-linux-gnuabi64
 
   gen:
     name: Update generated files

Cargo.toml

@@ -38,4 +38,5 @@ system = []
 default = ["std", "general", "errno"]
 std = []
 no_std = []
+elf = []
 rustc-dep-of-std = ["core", "compiler_builtins", "no_std"]

gen/src/main.rs

@@ -173,6 +173,7 @@ fn main() {
     writeln!(cargo_toml, "default = [\"std\", {}]", DEFAULT_FEATURES).unwrap();
     writeln!(cargo_toml, "std = []").unwrap();
     writeln!(cargo_toml, "no_std = []").unwrap();
+    writeln!(cargo_toml, "elf = []").unwrap();
     writeln!(
         cargo_toml,
         "rustc-dep-of-std = [\"core\", \"compiler_builtins\", \"no_std\"]"

src/elf.rs

@@ -0,0 +1,256 @@
+//! The ELF ABI. 🧝
+
+pub const SELFMAG: usize = 4;
+pub const ELFMAG: [u8; SELFMAG] = [0x7f, b'E', b'L', b'F'];
+pub const EI_CLASS: usize = 4;
+pub const EI_DATA: usize = 5;
+pub const EI_VERSION: usize = 6;
+pub const EI_OSABI: usize = 7;
+pub const EI_ABIVERSION: usize = 8;
+pub const EV_CURRENT: u8 = 1;
+#[cfg(target_pointer_width = "32")]
+pub const ELFCLASS: u8 = 1; // ELFCLASS32
+#[cfg(target_pointer_width = "64")]
+pub const ELFCLASS: u8 = 2; // ELFCLASS64
+#[cfg(target_endian = "little")]
+pub const ELFDATA: u8 = 1; // ELFDATA2LSB
+#[cfg(target_endian = "big")]
+pub const ELFDATA: u8 = 2; // ELFDATA2MSB
+pub const ELFOSABI_SYSV: u8 = 0;
+pub const ELFOSABI_LINUX: u8 = 3;
+// At present all of our supported platforms use 0.
+pub const ELFABIVERSION: u8 = 0;
+pub const ET_DYN: u16 = 3;
+pub const EI_NIDENT: usize = 16;
+pub const SHN_UNDEF: u16 = 0;
+pub const SHN_ABS: u16 = 0xfff1;
+pub const PN_XNUM: u16 = 0xffff;
+pub const PT_LOAD: u32 = 1;
+pub const PT_DYNAMIC: u32 = 2;
+pub const PT_INTERP: u32 = 3;
+pub const PT_PHDR: u32 = 6;
+pub const PT_TLS: u32 = 7;
+pub const PT_GNU_STACK: u32 = 0x6474_e551;
+pub const PT_GNU_RELRO: u32 = 0x6474_e552;
+pub const PF_X: u32 = 1;
+pub const PF_W: u32 = 2;
+pub const PF_R: u32 = 4;
+pub const DT_NULL: usize = 0;
+pub const DT_HASH: usize = 4;
+pub const DT_STRTAB: usize = 5;
+pub const DT_SYMTAB: usize = 6;
+pub const DT_RELA: usize = 7;
+pub const DT_RELASZ: usize = 8;
+pub const DT_RELAENT: usize = 9;
+pub const DT_SYMENT: usize = 11;
+pub const DT_VERSYM: usize = 0x6fff_fff0;
+pub const DT_VERDEF: usize = 0x6fff_fffc;
+pub const STB_WEAK: u8 = 2;
+pub const STB_GLOBAL: u8 = 1;
+pub const STT_NOTYPE: u8 = 0;
+pub const STT_FUNC: u8 = 2;
+pub const STN_UNDEF: u32 = 0;
+pub const VER_FLG_BASE: u16 = 0x1;
+pub const VER_DEF_CURRENT: u16 = 1;
+pub const STV_DEFAULT: u8 = 0;
+#[cfg(target_arch = "arm")]
+pub const EM_CURRENT: u16 = 40; // EM_ARM
+#[cfg(target_arch = "x86")]
+pub const EM_CURRENT: u16 = 3; // EM_386
+#[cfg(target_arch = "powerpc64")]
+pub const EM_CURRENT: u16 = 21; // EM_PPC64
+#[cfg(any(
+    target_arch = "mips",
+    target_arch = "mips32r6",
+    target_arch = "mips64",
+    target_arch = "mips64r6"
+))]
+pub const EM_CURRENT: u16 = 8; // EM_MIPS
+#[cfg(target_arch = "x86_64")]
+pub const EM_CURRENT: u16 = 62; // EM_X86_64
+#[cfg(target_arch = "aarch64")]
+pub const EM_CURRENT: u16 = 183; // EM_AARCH64
+#[cfg(target_arch = "riscv64")]
+pub const EM_CURRENT: u16 = 243; // EM_RISCV
+
+#[inline]
+pub const fn ELF_ST_VISIBILITY(o: u8) -> u8 {
+    o & 0x03
+}
+
+#[inline]
+pub const fn ELF_ST_BIND(val: u8) -> u8 {
+    val >> 4
+}
+
+#[inline]
+pub const fn ELF_ST_TYPE(val: u8) -> u8 {
+    val & 0xf
+}
+
+#[repr(C)]
+pub struct Elf_Ehdr {
+    pub e_ident: [u8; EI_NIDENT],
+    pub e_type: u16,
+    pub e_machine: u16,
+    pub e_version: u32,
+    pub e_entry: usize,
+    pub e_phoff: usize,
+    pub e_shoff: usize,
+    pub e_flags: u32,
+    pub e_ehsize: u16,
+    pub e_phentsize: u16,
+    pub e_phnum: u16,
+    pub e_shentsize: u16,
+    pub e_shnum: u16,
+    pub e_shstrndx: u16,
+}
+
+#[cfg(target_pointer_width = "32")]
+#[repr(C)]
+pub struct Elf_Phdr {
+    pub p_type: u32,
+    pub p_offset: usize,
+    pub p_vaddr: usize,
+    pub p_paddr: usize,
+    pub p_filesz: usize,
+    pub p_memsz: usize,
+    pub p_flags: u32,
+    pub p_align: usize,
+}
+
+#[cfg(target_pointer_width = "64")]
+#[repr(C)]
+pub struct Elf_Phdr {
+    pub p_type: u32,
+    pub p_flags: u32,
+    pub p_offset: usize,
+    pub p_vaddr: usize,
+    pub p_paddr: usize,
+    pub p_filesz: usize,
+    pub p_memsz: usize,
+    pub p_align: usize,
+}
+
+#[cfg(target_pointer_width = "32")]
+#[repr(C)]
+pub struct Elf_Sym {
+    pub st_name: u32,
+    pub st_value: usize,
+    pub st_size: usize,
+    pub st_info: u8,
+    pub st_other: u8,
+    pub st_shndx: u16,
+}
+
+#[cfg(target_pointer_width = "64")]
+#[repr(C)]
+pub struct Elf_Sym {
+    pub st_name: u32,
+    pub st_info: u8,
+    pub st_other: u8,
+    pub st_shndx: u16,
+    pub st_value: usize,
+    pub st_size: usize,
+}
+
+#[repr(C)]
+pub struct Elf_Verdef {
+    pub vd_version: u16,
+    pub vd_flags: u16,
+    pub vd_ndx: u16,
+    pub vd_cnt: u16,
+    pub vd_hash: u32,
+    pub vd_aux: u32,
+    pub vd_next: u32,
+}
+
+#[repr(C)]
+pub struct Elf_Verdaux {
+    pub vda_name: u32,
+    pub _vda_next: u32,
+}
+
+#[cfg(target_pointer_width = "32")]
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct Elf_Dyn {
+    pub d_tag: usize,
+    pub d_un: Elf_Dyn_Union,
+}
+
+#[cfg(target_pointer_width = "32")]
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub union Elf_Dyn_Union {
+    pub d_val: u32,
+    pub d_ptr: usize,
+}
+
+#[cfg(target_pointer_width = "64")]
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct Elf_Dyn {
+    pub d_tag: usize,
+    pub d_un: Elf_Dyn_Union,
+}
+
+#[cfg(target_pointer_width = "64")]
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub union Elf_Dyn_Union {
+    pub d_val: u64,
+    pub d_ptr: usize,
+}
+
+#[cfg(target_pointer_width = "32")]
+#[repr(C)]
+pub struct Elf_Rela {
+    pub r_offset: usize,
+    pub r_info: u32,
+    pub r_addend: usize,
+}
+
+#[cfg(target_pointer_width = "64")]
+#[repr(C)]
+pub struct Elf_Rela {
+    pub r_offset: usize,
+    pub r_info: u64,
+    pub r_addend: usize,
+}
+
+impl Elf_Rela {
+    #[inline]
+    pub fn type_(&self) -> u32 {
+        #[cfg(target_pointer_width = "32")]
+        {
+            self.r_info & 0xff
+        }
+        #[cfg(target_pointer_width = "64")]
+        {
+            (self.r_info & 0xffff_ffff) as u32
+        }
+    }
+}
+
+#[cfg(target_arch = "x86_64")]
+pub const R_RELATIVE: u32 = 8; // `R_X86_64_RELATIVE`
+#[cfg(target_arch = "x86")]
+pub const R_RELATIVE: u32 = 8; // `R_386_RELATIVE`
+#[cfg(target_arch = "aarch64")]
+pub const R_RELATIVE: u32 = 1027; // `R_AARCH64_RELATIVE`
+#[cfg(target_arch = "riscv64")]
+pub const R_RELATIVE: u32 = 3; // `R_RISCV_RELATIVE`
+#[cfg(target_arch = "arm")]
+pub const R_RELATIVE: u32 = 23; // `R_ARM_RELATIVE`
+
+#[repr(C)]
+#[derive(Clone)]
+pub 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 crate::ctypes::c_void,
+}

src/lib.rs

@@ -186,6 +186,9 @@ pub mod signal_macros {
     }
 }
 
+#[cfg(feature = "elf")]
+pub mod elf;
+
 // The rest of this file is auto-generated!
 #[cfg(feature = "errno")]
 #[cfg(target_arch = "arm")]