vivisect/mach/
bind_opcodes.rs

1//! Bind opcodes are interpreted by the dynamic linker to efficiently collect every symbol imported by this binary, and from which library using two-level namespacing
2//!
3//! Some uses of external symbols do not need to be bound immediately.
4//! Instead they can be lazily bound on first use.  The lazy_bind
5//! are contains a stream of BIND opcodes to bind all lazy symbols.
6//! Normal use is that dyld ignores the lazy_bind section when
7//! loading an image.  Instead the static linker arranged for a
8//! lazy pointer to initially point to a helper function which
9//! pushes the offset into the lazy_bind area for the symbol
10//! needing to be bound, then jumps to dyld which simply adds
11//! the offset to lazy_bind_off to get the information on what
12//! to bind.
13
14pub type Opcode = u8;
15
16// The following are used to encode binding information
17pub const BIND_TYPE_POINTER: u8 = 1;
18pub const BIND_TYPE_TEXT_ABSOLUTE32: u8 = 2;
19pub const BIND_TYPE_TEXT_PCREL32: u8 = 3;
20pub const BIND_SPECIAL_DYLIB_SELF: u8 = 0;
21pub const BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE: u8 = 0xf; // -1
22pub const BIND_SPECIAL_DYLIB_FLAT_LOOKUP: u8 = 0xe; // -2
23pub const BIND_SYMBOL_FLAGS_WEAK_IMPORT: u8 = 0x1;
24pub const BIND_SYMBOL_FLAGS_NON_WEAK_DEFINITION: u8 = 0x8;
25pub const BIND_OPCODE_MASK: u8 = 0xF0;
26pub const BIND_IMMEDIATE_MASK: u8 = 0x0F;
27pub const BIND_OPCODE_DONE: Opcode = 0x00;
28pub const BIND_OPCODE_SET_DYLIB_ORDINAL_IMM: Opcode = 0x10;
29pub const BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB: Opcode = 0x20;
30pub const BIND_OPCODE_SET_DYLIB_SPECIAL_IMM: Opcode = 0x30;
31pub const BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM: Opcode = 0x40;
32pub const BIND_OPCODE_SET_TYPE_IMM: Opcode = 0x50;
33pub const BIND_OPCODE_SET_ADDEND_SLEB: Opcode = 0x60;
34pub const BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB: Opcode = 0x70;
35pub const BIND_OPCODE_ADD_ADDR_ULEB: Opcode = 0x80;
36pub const BIND_OPCODE_DO_BIND: Opcode = 0x90;
37pub const BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB: Opcode = 0xA0;
38pub const BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED: Opcode = 0xB0;
39pub const BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB: Opcode = 0xC0;
40
41pub fn opcode_to_str(opcode: Opcode) -> &'static str {
42    match opcode {
43        BIND_OPCODE_DONE => "BIND_OPCODE_DONE",
44        BIND_OPCODE_SET_DYLIB_ORDINAL_IMM => "BIND_OPCODE_SET_DYLIB_ORDINAL_IMM",
45        BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB => "BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB",
46        BIND_OPCODE_SET_DYLIB_SPECIAL_IMM => "BIND_OPCODE_SET_DYLIB_SPECIAL_IMM",
47        BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM => "BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM",
48        BIND_OPCODE_SET_TYPE_IMM => "BIND_OPCODE_SET_TYPE_IMM",
49        BIND_OPCODE_SET_ADDEND_SLEB => "BIND_OPCODE_SET_ADDEND_SLEB",
50        BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB => "BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB",
51        BIND_OPCODE_ADD_ADDR_ULEB => "BIND_OPCODE_ADD_ADDR_ULEB",
52        BIND_OPCODE_DO_BIND => "BIND_OPCODE_DO_BIND",
53        BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB => "BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB",
54        BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED => "BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED",
55        BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB => {
56            "BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB"
57        }
58        _ => "UNKNOWN OPCODE",
59    }
60}
vivisect/mach/bind_opcodes.rs

vivisect/mach/
bind_opcodes.rs
