path: root/lib/std/macho.zig

// SPDX-License-Identifier: MIT
// Copyright (c) 2015-2020 Zig Contributors
// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
// The MIT license requires this copyright notice to be included in all copies
// and substantial portions of the software.
pub const mach_header = extern struct {
    magic: u32,
    cputype: cpu_type_t,
    cpusubtype: cpu_subtype_t,
    filetype: u32,
    ncmds: u32,
    sizeofcmds: u32,
    flags: u32,
};

pub const mach_header_64 = extern struct {
    magic: u32,
    cputype: cpu_type_t,
    cpusubtype: cpu_subtype_t,
    filetype: u32,
    ncmds: u32,
    sizeofcmds: u32,
    flags: u32,
    reserved: u32,
};

pub const load_command = extern struct {
    cmd: u32,
    cmdsize: u32,
};

pub const uuid_command = extern struct {
    /// LC_UUID
    cmd: u32,

    /// sizeof(struct uuid_command)
    cmdsize: u32,

    /// the 128-bit uuid
    uuid: [16]u8,
};

/// The entry_point_command is a replacement for thread_command.
/// It is used for main executables to specify the location (file offset)
/// of main(). If -stack_size was used at link time, the stacksize
/// field will contain the stack size needed for the main thread.
pub const entry_point_command = struct {
    /// LC_MAIN only used in MH_EXECUTE filetypes
    cmd: u32,

    /// sizeof(struct entry_point_command)
    cmdsize: u32,

    /// file (__TEXT) offset of main()
    entryoff: u64,

    /// if not zero, initial stack size
    stacksize: u64,
};

/// The symtab_command contains the offsets and sizes of the link-edit 4.3BSD
/// "stab" style symbol table information as described in the header files
/// <nlist.h> and <stab.h>.
pub const symtab_command = extern struct {
    /// LC_SYMTAB
    cmd: u32,

    /// sizeof(struct symtab_command)
    cmdsize: u32,

    /// symbol table offset
    symoff: u32,

    /// number of symbol table entries
    nsyms: u32,

    /// string table offset
    stroff: u32,

    /// string table size in bytes
    strsize: u32,
};

/// This is the second set of the symbolic information which is used to support
/// the data structures for the dynamically link editor.
///
/// The original set of symbolic information in the symtab_command which contains
/// the symbol and string tables must also be present when this load command is
/// present.  When this load command is present the symbol table is organized
/// into three groups of symbols:
///  local symbols (static and debugging symbols) - grouped by module
///  defined external symbols - grouped by module (sorted by name if not lib)
///  undefined external symbols (sorted by name if MH_BINDATLOAD is not set,
///       			    and in order the were seen by the static
///  			    linker if MH_BINDATLOAD is set)
/// In this load command there are offsets and counts to each of the three groups
/// of symbols.
///
/// This load command contains a the offsets and sizes of the following new
/// symbolic information tables:
///  table of contents
///  module table
///  reference symbol table
///  indirect symbol table
/// The first three tables above (the table of contents, module table and
/// reference symbol table) are only present if the file is a dynamically linked
/// shared library.  For executable and object modules, which are files
/// containing only one module, the information that would be in these three
/// tables is determined as follows:
/// 	table of contents - the defined external symbols are sorted by name
///  module table - the file contains only one module so everything in the
///  	       file is part of the module.
///  reference symbol table - is the defined and undefined external symbols
///
/// For dynamically linked shared library files this load command also contains
/// offsets and sizes to the pool of relocation entries for all sections
/// separated into two groups:
///  external relocation entries
///  local relocation entries
/// For executable and object modules the relocation entries continue to hang
/// off the section structures.
pub const dysymtab_command = extern struct {
    /// LC_DYSYMTAB
    cmd: u32,

    /// sizeof(struct dysymtab_command)
    cmdsize: u32,

    // The symbols indicated by symoff and nsyms of the LC_SYMTAB load command
    // are grouped into the following three groups:
    //    local symbols (further grouped by the module they are from)
    //    defined external symbols (further grouped by the module they are from)
    //    undefined symbols
    //
    // The local symbols are used only for debugging.  The dynamic binding
    // process may have to use them to indicate to the debugger the local
    // symbols for a module that is being bound.
    //
    // The last two groups are used by the dynamic binding process to do the
    // binding (indirectly through the module table and the reference symbol
    // table when this is a dynamically linked shared library file).

    /// index of local symbols
    ilocalsym: u32,

    /// number of local symbols
    nlocalsym: u32,

    /// index to externally defined symbols
    iextdefsym: u32,

    /// number of externally defined symbols
    nextdefsym: u32,

    /// index to undefined symbols
    iundefsym: u32,

    /// number of undefined symbols
    nundefsym: u32,

    // For the for the dynamic binding process to find which module a symbol
    // is defined in the table of contents is used (analogous to the ranlib
    // structure in an archive) which maps defined external symbols to modules
    // they are defined in.  This exists only in a dynamically linked shared
    // library file.  For executable and object modules the defined external
    // symbols are sorted by name and is use as the table of contents.

    /// file offset to table of contents
    tocoff: u32,

    /// number of entries in table of contents
    ntoc: u32,

    // To support dynamic binding of "modules" (whole object files) the symbol
    // table must reflect the modules that the file was created from.  This is
    // done by having a module table that has indexes and counts into the merged
    // tables for each module.  The module structure that these two entries
    // refer to is described below.  This exists only in a dynamically linked
    // shared library file.  For executable and object modules the file only
    // contains one module so everything in the file belongs to the module.

    /// file offset to module table
    modtaboff: u32,

    /// number of module table entries
    nmodtab: u32,

    // To support dynamic module binding the module structure for each module
    // indicates the external references (defined and undefined) each module
    // makes.  For each module there is an offset and a count into the
    // reference symbol table for the symbols that the module references.
    // This exists only in a dynamically linked shared library file.  For
    // executable and object modules the defined external symbols and the
    // undefined external symbols indicates the external references.

    /// offset to referenced symbol table
    extrefsymoff: u32,

    /// number of referenced symbol table entries
    nextrefsyms: u32,

    // The sections that contain "symbol pointers" and "routine stubs" have
    // indexes and (implied counts based on the size of the section and fixed
    // size of the entry) into the "indirect symbol" table for each pointer
    // and stub.  For every section of these two types the index into the
    // indirect symbol table is stored in the section header in the field
    // reserved1.  An indirect symbol table entry is simply a 32bit index into
    // the symbol table to the symbol that the pointer or stub is referring to.
    // The indirect symbol table is ordered to match the entries in the section.

    /// file offset to the indirect symbol table
    indirectsymoff: u32,

    /// number of indirect symbol table entries
    nindirectsyms: u32,

    // To support relocating an individual module in a library file quickly the
    // external relocation entries for each module in the library need to be
    // accessed efficiently.  Since the relocation entries can't be accessed
    // through the section headers for a library file they are separated into
    // groups of local and external entries further grouped by module.  In this
    // case the presents of this load command who's extreloff, nextrel,
    // locreloff and nlocrel fields are non-zero indicates that the relocation
    // entries of non-merged sections are not referenced through the section
    // structures (and the reloff and nreloc fields in the section headers are
    // set to zero).
    //
    // Since the relocation entries are not accessed through the section headers
    // this requires the r_address field to be something other than a section
    // offset to identify the item to be relocated.  In this case r_address is
    // set to the offset from the vmaddr of the first LC_SEGMENT command.
    // For MH_SPLIT_SEGS images r_address is set to the the offset from the
    // vmaddr of the first read-write LC_SEGMENT command.
    //
    // The relocation entries are grouped by module and the module table
    // entries have indexes and counts into them for the group of external
    // relocation entries for that the module.
    //
    // For sections that are merged across modules there must not be any
    // remaining external relocation entries for them (for merged sections
    // remaining relocation entries must be local).

    /// offset to external relocation entries
    extreloff: u32,

    /// number of external relocation entries
    nextrel: u32,

    // All the local relocation entries are grouped together (they are not
    // grouped by their module since they are only used if the object is moved
    // from it staticly link edited address).

    /// offset to local relocation entries
    locreloff: u32,

    /// number of local relocation entries
    nlocrel: u32,
};

/// The linkedit_data_command contains the offsets and sizes of a blob
/// of data in the __LINKEDIT segment.
pub const linkedit_data_command = extern struct {
    /// LC_CODE_SIGNATURE, LC_SEGMENT_SPLIT_INFO, LC_FUNCTION_STARTS, LC_DATA_IN_CODE, LC_DYLIB_CODE_SIGN_DRS or LC_LINKER_OPTIMIZATION_HINT.
    cmd: u32,

    /// sizeof(struct linkedit_data_command)
    cmdsize: u32,

    /// file offset of data in __LINKEDIT segment
    dataoff: u32,

    /// file size of data in __LINKEDIT segment
    datasize: u32,
};

/// The dyld_info_command contains the file offsets and sizes of
/// the new compressed form of the information dyld needs to
/// load the image.  This information is used by dyld on Mac OS X
/// 10.6 and later.  All information pointed to by this command
/// is encoded using byte streams, so no endian swapping is needed
/// to interpret it.
pub const dyld_info_command = extern struct {
    /// LC_DYLD_INFO or LC_DYLD_INFO_ONLY
    cmd: u32,

    /// sizeof(struct dyld_info_command)
    cmdsize: u32,

    // Dyld rebases an image whenever dyld loads it at an address different
    // from its preferred address.  The rebase information is a stream
    // of byte sized opcodes whose symbolic names start with REBASE_OPCODE_.
    // Conceptually the rebase information is a table of tuples:
    //    <seg-index, seg-offset, type>
    // The opcodes are a compressed way to encode the table by only
    // encoding when a column changes.  In addition simple patterns
    // like "every n'th offset for m times" can be encoded in a few
    // bytes.

    /// file offset to rebase info
    rebase_off: u32,

    /// size of rebase info
    rebase_size: u32,

    // Dyld binds an image during the loading process, if the image
    // requires any pointers to be initialized to symbols in other images.
    // The bind information is a stream of byte sized
    // opcodes whose symbolic names start with BIND_OPCODE_.
    // Conceptually the bind information is a table of tuples:
    //    <seg-index, seg-offset, type, symbol-library-ordinal, symbol-name, addend>
    // The opcodes are a compressed way to encode the table by only
    // encoding when a column changes.  In addition simple patterns
    // like for runs of pointers initialzed to the same value can be
    // encoded in a few bytes.

    /// file offset to binding info
    bind_off: u32,

    /// size of binding info
    bind_size: u32,

    // Some C++ programs require dyld to unique symbols so that all
    // images in the process use the same copy of some code/data.
    // This step is done after binding. The content of the weak_bind
    // info is an opcode stream like the bind_info.  But it is sorted
    // alphabetically by symbol name.  This enable dyld to walk
    // all images with weak binding information in order and look
    // for collisions.  If there are no collisions, dyld does
    // no updating.  That means that some fixups are also encoded
    // in the bind_info.  For instance, all calls to "operator new"
    // are first bound to libstdc++.dylib using the information
    // in bind_info.  Then if some image overrides operator new
    // that is detected when the weak_bind information is processed
    // and the call to operator new is then rebound.

    /// file offset to weak binding info
    weak_bind_off: u32,

    /// size of weak binding info
    weak_bind_size: u32,

    // Some uses of external symbols do not need to be bound immediately.
    // Instead they can be lazily bound on first use.  The lazy_bind
    // are contains a stream of BIND opcodes to bind all lazy symbols.
    // Normal use is that dyld ignores the lazy_bind section when
    // loading an image.  Instead the static linker arranged for the
    // lazy pointer to initially point to a helper function which
    // pushes the offset into the lazy_bind area for the symbol
    // needing to be bound, then jumps to dyld which simply adds
    // the offset to lazy_bind_off to get the information on what
    // to bind.

    /// file offset to lazy binding info
    lazy_bind_off: u32,

    /// size of lazy binding info
    lazy_bind_size: u32,

    // The symbols exported by a dylib are encoded in a trie.  This
    // is a compact representation that factors out common prefixes.
    // It also reduces LINKEDIT pages in RAM because it encodes all
    // information (name, address, flags) in one small, contiguous range.
    // The export area is a stream of nodes.  The first node sequentially
    // is the start node for the trie.
    //
    // Nodes for a symbol start with a uleb128 that is the length of
    // the exported symbol information for the string so far.
    // If there is no exported symbol, the node starts with a zero byte.
    // If there is exported info, it follows the length.
    //
    // First is a uleb128 containing flags. Normally, it is followed by
    // a uleb128 encoded offset which is location of the content named
    // by the symbol from the mach_header for the image.  If the flags
    // is EXPORT_SYMBOL_FLAGS_REEXPORT, then following the flags is
    // a uleb128 encoded library ordinal, then a zero terminated
    // UTF8 string.  If the string is zero length, then the symbol
    // is re-export from the specified dylib with the same name.
    // If the flags is EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER, then following
    // the flags is two uleb128s: the stub offset and the resolver offset.
    // The stub is used by non-lazy pointers.  The resolver is used
    // by lazy pointers and must be called to get the actual address to use.
    //
    // After the optional exported symbol information is a byte of
    // how many edges (0-255) that this node has leaving it,
    // followed by each edge.
    // Each edge is a zero terminated UTF8 of the addition chars
    // in the symbol, followed by a uleb128 offset for the node that
    // edge points to.

    /// file offset to lazy binding info
    export_off: u32,

    /// size of lazy binding info
    export_size: u32,
};

/// A program that uses a dynamic linker contains a dylinker_command to identify
/// the name of the dynamic linker (LC_LOAD_DYLINKER). And a dynamic linker
/// contains a dylinker_command to identify the dynamic linker (LC_ID_DYLINKER).
/// A file can have at most one of these.
/// This struct is also used for the LC_DYLD_ENVIRONMENT load command and contains
/// string for dyld to treat like an environment variable.
pub const dylinker_command = extern struct {
    /// LC_ID_DYLINKER, LC_LOAD_DYLINKER, or LC_DYLD_ENVIRONMENT
    cmd: u32,

    /// includes pathname string
    cmdsize: u32,

    /// A variable length string in a load command is represented by an lc_str
    /// union.  The strings are stored just after the load command structure and
    /// the offset is from the start of the load command structure.  The size
    /// of the string is reflected in the cmdsize field of the load command.
    /// Once again any padded bytes to bring the cmdsize field to a multiple
    /// of 4 bytes must be zero.
    name: u32,
};

/// A dynamically linked shared library (filetype == MH_DYLIB in the mach header)
/// contains a dylib_command (cmd == LC_ID_DYLIB) to identify the library.
/// An object that uses a dynamically linked shared library also contains a
/// dylib_command (cmd == LC_LOAD_DYLIB, LC_LOAD_WEAK_DYLIB, or
/// LC_REEXPORT_DYLIB) for each library it uses.
pub const dylib_command = extern struct {
    /// LC_ID_DYLIB, LC_LOAD_WEAK_DYLIB, LC_LOAD_DYLIB, LC_REEXPORT_DYLIB
    cmd: u32,

    /// includes pathname string
    cmdsize: u32,

    /// the library identification
    dylib: dylib,
};

/// Dynamicaly linked shared libraries are identified by two things.  The
/// pathname (the name of the library as found for execution), and the
/// compatibility version number.  The pathname must match and the compatibility
/// number in the user of the library must be greater than or equal to the
/// library being used.  The time stamp is used to record the time a library was
/// built and copied into user so it can be use to determined if the library used
/// at runtime is exactly the same as used to built the program.
pub const dylib = extern struct {
    /// library's pathname (offset pointing at the end of dylib_command)
    name: u32,

    /// library's build timestamp
    timestamp: u32,

    /// library's current version number
    current_version: u32,

    /// library's compatibility version number
    compatibility_version: u32,
};

/// The segment load command indicates that a part of this file is to be
/// mapped into the task's address space.  The size of this segment in memory,
/// vmsize, maybe equal to or larger than the amount to map from this file,
/// filesize.  The file is mapped starting at fileoff to the beginning of
/// the segment in memory, vmaddr.  The rest of the memory of the segment,
/// if any, is allocated zero fill on demand.  The segment's maximum virtual
/// memory protection and initial virtual memory protection are specified
/// by the maxprot and initprot fields.  If the segment has sections then the
/// section structures directly follow the segment command and their size is
/// reflected in cmdsize.
pub const segment_command = extern struct {
    /// LC_SEGMENT
    cmd: u32,

    /// includes sizeof section structs
    cmdsize: u32,

    /// segment name
    segname: [16]u8,

    /// memory address of this segment
    vmaddr: u32,

    /// memory size of this segment
    vmsize: u32,

    /// file offset of this segment
    fileoff: u32,

    /// amount to map from the file
    filesize: u32,

    /// maximum VM protection
    maxprot: vm_prot_t,

    /// initial VM protection
    initprot: vm_prot_t,

    /// number of sections in segment
    nsects: u32,
    flags: u32,
};

/// The 64-bit segment load command indicates that a part of this file is to be
/// mapped into a 64-bit task's address space.  If the 64-bit segment has
/// sections then section_64 structures directly follow the 64-bit segment
/// command and their size is reflected in cmdsize.
pub const segment_command_64 = extern struct {
    /// LC_SEGMENT_64
    cmd: u32,

    /// includes sizeof section_64 structs
    cmdsize: u32,

    /// segment name
    segname: [16]u8,

    /// memory address of this segment
    vmaddr: u64,

    /// memory size of this segment
    vmsize: u64,

    /// file offset of this segment
    fileoff: u64,

    /// amount to map from the file
    filesize: u64,

    /// maximum VM protection
    maxprot: vm_prot_t,

    /// initial VM protection
    initprot: vm_prot_t,

    /// number of sections in segment
    nsects: u32,
    flags: u32,
};

/// A segment is made up of zero or more sections.  Non-MH_OBJECT files have
/// all of their segments with the proper sections in each, and padded to the
/// specified segment alignment when produced by the link editor.  The first
/// segment of a MH_EXECUTE and MH_FVMLIB format file contains the mach_header
/// and load commands of the object file before its first section.  The zero
/// fill sections are always last in their segment (in all formats).  This
/// allows the zeroed segment padding to be mapped into memory where zero fill
/// sections might be. The gigabyte zero fill sections, those with the section
/// type S_GB_ZEROFILL, can only be in a segment with sections of this type.
/// These segments are then placed after all other segments.
///
/// The MH_OBJECT format has all of its sections in one segment for
/// compactness.  There is no padding to a specified segment boundary and the
/// mach_header and load commands are not part of the segment.
///
/// Sections with the same section name, sectname, going into the same segment,
/// segname, are combined by the link editor.  The resulting section is aligned
/// to the maximum alignment of the combined sections and is the new section's
/// alignment.  The combined sections are aligned to their original alignment in
/// the combined section.  Any padded bytes to get the specified alignment are
/// zeroed.
///
/// The format of the relocation entries referenced by the reloff and nreloc
/// fields of the section structure for mach object files is described in the
/// header file <reloc.h>.
pub const @"section" = extern struct {
    /// name of this section
    sectname: [16]u8,

    /// segment this section goes in
    segname: [16]u8,

    /// memory address of this section
    addr: u32,

    /// size in bytes of this section
    size: u32,

    /// file offset of this section
    offset: u32,

    /// section alignment (power of 2)
    @"align": u32,

    /// file offset of relocation entries
    reloff: u32,

    /// number of relocation entries
    nreloc: u32,

    /// flags (section type and attributes
    flags: u32,

    /// reserved (for offset or index)
    reserved1: u32,

    /// reserved (for count or sizeof)
    reserved2: u32,
};

pub const section_64 = extern struct {
    /// name of this section
    sectname: [16]u8,

    /// segment this section goes in
    segname: [16]u8,

    /// memory address of this section
    addr: u64,

    /// size in bytes of this section
    size: u64,

    /// file offset of this section
    offset: u32,

    /// section alignment (power of 2)
    @"align": u32,

    /// file offset of relocation entries
    reloff: u32,

    /// number of relocation entries
    nreloc: u32,

    /// flags (section type and attributes
    flags: u32,

    /// reserved (for offset or index)
    reserved1: u32,

    /// reserved (for count or sizeof)
    reserved2: u32,

    /// reserved
    reserved3: u32,
};

pub const nlist = extern struct {
    n_strx: u32,
    n_type: u8,
    n_sect: u8,
    n_desc: i16,
    n_value: u32,
};

pub const nlist_64 = extern struct {
    n_strx: u32,
    n_type: u8,
    n_sect: u8,
    n_desc: u16,
    n_value: u64,
};

/// Format of a relocation entry of a Mach-O file.  Modified from the 4.3BSD
/// format.  The modifications from the original format were changing the value
/// of the r_symbolnum field for "local" (r_extern == 0) relocation entries.
/// This modification is required to support symbols in an arbitrary number of
/// sections not just the three sections (text, data and bss) in a 4.3BSD file.
/// Also the last 4 bits have had the r_type tag added to them.
pub const relocation_info = packed struct {
    /// offset in the section to what is being relocated
    r_address: i32,

    /// symbol index if r_extern == 1 or section ordinal if r_extern == 0
    r_symbolnum: u24,

    /// was relocated pc relative already
    r_pcrel: u1,

    /// 0=byte, 1=word, 2=long, 3=quad
    r_length: u2,

    /// does not include value of sym referenced
    r_extern: u1,

    /// if not 0, machine specific relocation type
    r_type: u4,
};

/// After MacOS X 10.1 when a new load command is added that is required to be
/// understood by the dynamic linker for the image to execute properly the
/// LC_REQ_DYLD bit will be or'ed into the load command constant.  If the dynamic
/// linker sees such a load command it it does not understand will issue a
/// "unknown load command required for execution" error and refuse to use the
/// image.  Other load commands without this bit that are not understood will
/// simply be ignored.
pub const LC_REQ_DYLD = 0x80000000;

/// segment of this file to be mapped
pub const LC_SEGMENT = 0x1;

/// link-edit stab symbol table info
pub const LC_SYMTAB = 0x2;

/// link-edit gdb symbol table info (obsolete)
pub const LC_SYMSEG = 0x3;

/// thread
pub const LC_THREAD = 0x4;

/// unix thread (includes a stack)
pub const LC_UNIXTHREAD = 0x5;

/// load a specified fixed VM shared library
pub const LC_LOADFVMLIB = 0x6;

/// fixed VM shared library identification
pub const LC_IDFVMLIB = 0x7;

/// object identification info (obsolete)
pub const LC_IDENT = 0x8;

/// fixed VM file inclusion (internal use)
pub const LC_FVMFILE = 0x9;

/// prepage command (internal use)
pub const LC_PREPAGE = 0xa;

/// dynamic link-edit symbol table info
pub const LC_DYSYMTAB = 0xb;

/// load a dynamically linked shared library
pub const LC_LOAD_DYLIB = 0xc;

/// dynamically linked shared lib ident
pub const LC_ID_DYLIB = 0xd;

/// load a dynamic linker
pub const LC_LOAD_DYLINKER = 0xe;

/// dynamic linker identification
pub const LC_ID_DYLINKER = 0xf;

/// modules prebound for a dynamically
pub const LC_PREBOUND_DYLIB = 0x10;

/// image routines
pub const LC_ROUTINES = 0x11;

/// sub framework
pub const LC_SUB_FRAMEWORK = 0x12;

/// sub umbrella
pub const LC_SUB_UMBRELLA = 0x13;

/// sub client
pub const LC_SUB_CLIENT = 0x14;

/// sub library
pub const LC_SUB_LIBRARY = 0x15;

/// two-level namespace lookup hints
pub const LC_TWOLEVEL_HINTS = 0x16;

/// prebind checksum
pub const LC_PREBIND_CKSUM = 0x17;

/// load a dynamically linked shared library that is allowed to be missing
/// (all symbols are weak imported).
pub const LC_LOAD_WEAK_DYLIB = (0x18 | LC_REQ_DYLD);

/// 64-bit segment of this file to be mapped
pub const LC_SEGMENT_64 = 0x19;

/// 64-bit image routines
pub const LC_ROUTINES_64 = 0x1a;

/// the uuid
pub const LC_UUID = 0x1b;

/// runpath additions
pub const LC_RPATH = (0x1c | LC_REQ_DYLD);

/// local of code signature
pub const LC_CODE_SIGNATURE = 0x1d;

/// local of info to split segments
pub const LC_SEGMENT_SPLIT_INFO = 0x1e;

/// load and re-export dylib
pub const LC_REEXPORT_DYLIB = (0x1f | LC_REQ_DYLD);

/// delay load of dylib until first use
pub const LC_LAZY_LOAD_DYLIB = 0x20;

/// encrypted segment information
pub const LC_ENCRYPTION_INFO = 0x21;

/// compressed dyld information
pub const LC_DYLD_INFO = 0x22;

/// compressed dyld information only
pub const LC_DYLD_INFO_ONLY = (0x22 | LC_REQ_DYLD);

/// load upward dylib
pub const LC_LOAD_UPWARD_DYLIB = (0x23 | LC_REQ_DYLD);

/// build for MacOSX min OS version
pub const LC_VERSION_MIN_MACOSX = 0x24;

/// build for iPhoneOS min OS version
pub const LC_VERSION_MIN_IPHONEOS = 0x25;

/// compressed table of function start addresses
pub const LC_FUNCTION_STARTS = 0x26;

/// string for dyld to treat like environment variable
pub const LC_DYLD_ENVIRONMENT = 0x27;

/// replacement for LC_UNIXTHREAD
pub const LC_MAIN = (0x28 | LC_REQ_DYLD);

/// table of non-instructions in __text
pub const LC_DATA_IN_CODE = 0x29;

/// source version used to build binary
pub const LC_SOURCE_VERSION = 0x2A;

/// Code signing DRs copied from linked dylibs
pub const LC_DYLIB_CODE_SIGN_DRS = 0x2B;

/// 64-bit encrypted segment information
pub const LC_ENCRYPTION_INFO_64 = 0x2C;

/// linker options in MH_OBJECT files
pub const LC_LINKER_OPTION = 0x2D;

/// optimization hints in MH_OBJECT files
pub const LC_LINKER_OPTIMIZATION_HINT = 0x2E;

/// build for AppleTV min OS version
pub const LC_VERSION_MIN_TVOS = 0x2F;

/// build for Watch min OS version
pub const LC_VERSION_MIN_WATCHOS = 0x30;

/// arbitrary data included within a Mach-O file
pub const LC_NOTE = 0x31;

/// build for platform min OS version
pub const LC_BUILD_VERSION = 0x32;

/// the mach magic number
pub const MH_MAGIC = 0xfeedface;

/// NXSwapInt(MH_MAGIC)
pub const MH_CIGAM = 0xcefaedfe;

/// the 64-bit mach magic number
pub const MH_MAGIC_64 = 0xfeedfacf;

/// NXSwapInt(MH_MAGIC_64)
pub const MH_CIGAM_64 = 0xcffaedfe;

/// relocatable object file
pub const MH_OBJECT = 0x1;

/// demand paged executable file
pub const MH_EXECUTE = 0x2;

/// fixed VM shared library file
pub const MH_FVMLIB = 0x3;

/// core file
pub const MH_CORE = 0x4;

/// preloaded executable file
pub const MH_PRELOAD = 0x5;

/// dynamically bound shared library
pub const MH_DYLIB = 0x6;

/// dynamic link editor
pub const MH_DYLINKER = 0x7;

/// dynamically bound bundle file
pub const MH_BUNDLE = 0x8;

/// shared library stub for static linking only, no section contents
pub const MH_DYLIB_STUB = 0x9;

/// companion file with only debug sections
pub const MH_DSYM = 0xa;

/// x86_64 kexts
pub const MH_KEXT_BUNDLE = 0xb;

// Constants for the flags field of the mach_header

/// the object file has no undefined references
pub const MH_NOUNDEFS = 0x1;

/// the object file is the output of an incremental link against a base file and can't be link edited again
pub const MH_INCRLINK = 0x2;

/// the object file is input for the dynamic linker and can't be staticly link edited again
pub const MH_DYLDLINK = 0x4;

/// the object file's undefined references are bound by the dynamic linker when loaded.
pub const MH_BINDATLOAD = 0x8;

/// the file has its dynamic undefined references prebound.
pub const MH_PREBOUND = 0x10;

/// the file has its read-only and read-write segments split
pub const MH_SPLIT_SEGS = 0x20;

/// the shared library init routine is to be run lazily via catching memory faults to its writeable segments (obsolete)
pub const MH_LAZY_INIT = 0x40;

/// the image is using two-level name space bindings
pub const MH_TWOLEVEL = 0x80;

/// the executable is forcing all images to use flat name space bindings
pub const MH_FORCE_FLAT = 0x100;

/// this umbrella guarantees no multiple defintions of symbols in its sub-images so the two-level namespace hints can always be used.
pub const MH_NOMULTIDEFS = 0x200;

/// do not have dyld notify the prebinding agent about this executable
pub const MH_NOFIXPREBINDING = 0x400;

/// the binary is not prebound but can have its prebinding redone. only used when MH_PREBOUND is not set.
pub const MH_PREBINDABLE = 0x800;

/// indicates that this binary binds to all two-level namespace modules of its dependent libraries. only used when MH_PREBINDABLE and MH_TWOLEVEL are both set.
pub const MH_ALLMODSBOUND = 0x1000;

/// safe to divide up the sections into sub-sections via symbols for dead code stripping
pub const MH_SUBSECTIONS_VIA_SYMBOLS = 0x2000;

/// the binary has been canonicalized via the unprebind operation
pub const MH_CANONICAL = 0x4000;

/// the final linked image contains external weak symbols
pub const MH_WEAK_DEFINES = 0x8000;

/// the final linked image uses weak symbols
pub const MH_BINDS_TO_WEAK = 0x10000;

/// When this bit is set, all stacks in the task will be given stack execution privilege.  Only used in MH_EXECUTE filetypes.
pub const MH_ALLOW_STACK_EXECUTION = 0x20000;

/// When this bit is set, the binary declares it is safe for use in processes with uid zero
pub const MH_ROOT_SAFE = 0x40000;

/// When this bit is set, the binary declares it is safe for use in processes when issetugid() is true
pub const MH_SETUID_SAFE = 0x80000;

/// When this bit is set on a dylib, the static linker does not need to examine dependent dylibs to see if any are re-exported
pub const MH_NO_REEXPORTED_DYLIBS = 0x100000;

/// When this bit is set, the OS will load the main executable at a random address.  Only used in MH_EXECUTE filetypes.
pub const MH_PIE = 0x200000;

/// Only for use on dylibs.  When linking against a dylib that has this bit set, the static linker will automatically not create a LC_LOAD_DYLIB load command to the dylib if no symbols are being referenced from the dylib.
pub const MH_DEAD_STRIPPABLE_DYLIB = 0x400000;

/// Contains a section of type S_THREAD_LOCAL_VARIABLES
pub const MH_HAS_TLV_DESCRIPTORS = 0x800000;

/// When this bit is set, the OS will run the main executable with a non-executable heap even on platforms (e.g. i386) that don't require it. Only used in MH_EXECUTE filetypes.
pub const MH_NO_HEAP_EXECUTION = 0x1000000;

/// The code was linked for use in an application extension.
pub const MH_APP_EXTENSION_SAFE = 0x02000000;

/// The external symbols listed in the nlist symbol table do not include all the symbols listed in the dyld info.
pub const MH_NLIST_OUTOFSYNC_WITH_DYLDINFO = 0x04000000;

/// The flags field of a section structure is separated into two parts a section
/// type and section attributes.  The section types are mutually exclusive (it
/// can only have one type) but the section attributes are not (it may have more
/// than one attribute).
/// 256 section types
pub const SECTION_TYPE = 0x000000ff;

///  24 section attributes
pub const SECTION_ATTRIBUTES = 0xffffff00;

/// regular section
pub const S_REGULAR = 0x0;

/// zero fill on demand section
pub const S_ZEROFILL = 0x1;

/// section with only literal C string
pub const S_CSTRING_LITERALS = 0x2;

/// section with only 4 byte literals
pub const S_4BYTE_LITERALS = 0x3;

/// section with only 8 byte literals
pub const S_8BYTE_LITERALS = 0x4;

/// section with only pointers to
pub const S_LITERAL_POINTERS = 0x5;

/// if any of these bits set, a symbolic debugging entry
pub const N_STAB = 0xe0;

/// private external symbol bit
pub const N_PEXT = 0x10;

/// mask for the type bits
pub const N_TYPE = 0x0e;

/// external symbol bit, set for external symbols
pub const N_EXT = 0x01;

/// symbol is undefined
pub const N_UNDF = 0x0;

/// symbol is absolute
pub const N_ABS = 0x2;

/// symbol is defined in the section number given in n_sect
pub const N_SECT = 0xe;

/// symbol is undefined  and the image is using a prebound
/// value  for the symbol
pub const N_PBUD = 0xc;

/// symbol is defined to be the same as another symbol; the n_value
/// field is an index into the string table specifying the name of the
/// other symbol
pub const N_INDR = 0xa;

/// global symbol: name,,NO_SECT,type,0
pub const N_GSYM = 0x20;

/// procedure name (f77 kludge): name,,NO_SECT,0,0
pub const N_FNAME = 0x22;

/// procedure: name,,n_sect,linenumber,address
pub const N_FUN = 0x24;

/// static symbol: name,,n_sect,type,address
pub const N_STSYM = 0x26;

/// .lcomm symbol: name,,n_sect,type,address
pub const N_LCSYM = 0x28;

/// begin nsect sym: 0,,n_sect,0,address
pub const N_BNSYM = 0x2e;

/// AST file path: name,,NO_SECT,0,0
pub const N_AST = 0x32;

/// emitted with gcc2_compiled and in gcc source
pub const N_OPT = 0x3c;

/// register sym: name,,NO_SECT,type,register
pub const N_RSYM = 0x40;

/// src line: 0,,n_sect,linenumber,address
pub const N_SLINE = 0x44;

/// end nsect sym: 0,,n_sect,0,address
pub const N_ENSYM = 0x4e;

/// structure elt: name,,NO_SECT,type,struct_offset
pub const N_SSYM = 0x60;

/// source file name: name,,n_sect,0,address
pub const N_SO = 0x64;

/// object file name: name,,0,0,st_mtime
pub const N_OSO = 0x66;

/// local sym: name,,NO_SECT,type,offset
pub const N_LSYM = 0x80;

/// include file beginning: name,,NO_SECT,0,sum
pub const N_BINCL = 0x82;

/// #included file name: name,,n_sect,0,address
pub const N_SOL = 0x84;

/// compiler parameters: name,,NO_SECT,0,0
pub const N_PARAMS = 0x86;

/// compiler version: name,,NO_SECT,0,0
pub const N_VERSION = 0x88;

/// compiler -O level: name,,NO_SECT,0,0
pub const N_OLEVEL = 0x8A;

/// parameter: name,,NO_SECT,type,offset
pub const N_PSYM = 0xa0;

/// include file end: name,,NO_SECT,0,0
pub const N_EINCL = 0xa2;

/// alternate entry: name,,n_sect,linenumber,address
pub const N_ENTRY = 0xa4;

/// left bracket: 0,,NO_SECT,nesting level,address
pub const N_LBRAC = 0xc0;

/// deleted include file: name,,NO_SECT,0,sum
pub const N_EXCL = 0xc2;

/// right bracket: 0,,NO_SECT,nesting level,address
pub const N_RBRAC = 0xe0;

/// begin common: name,,NO_SECT,0,0
pub const N_BCOMM = 0xe2;

/// end common: name,,n_sect,0,0
pub const N_ECOMM = 0xe4;

/// end common (local name): 0,,n_sect,0,address
pub const N_ECOML = 0xe8;

/// second stab entry with length information
pub const N_LENG = 0xfe;

// For the two types of symbol pointers sections and the symbol stubs section
// they have indirect symbol table entries.  For each of the entries in the
// section the indirect symbol table entries, in corresponding order in the
// indirect symbol table, start at the index stored in the reserved1 field
// of the section structure.  Since the indirect symbol table entries
// correspond to the entries in the section the number of indirect symbol table
// entries is inferred from the size of the section divided by the size of the
// entries in the section.  For symbol pointers sections the size of the entries
// in the section is 4 bytes and for symbol stubs sections the byte size of the
// stubs is stored in the reserved2 field of the section structure.

/// section with only non-lazy symbol pointers
pub const S_NON_LAZY_SYMBOL_POINTERS = 0x6;

/// section with only lazy symbol pointers
pub const S_LAZY_SYMBOL_POINTERS = 0x7;

/// section with only symbol stubs, byte size of stub in the reserved2 field
pub const S_SYMBOL_STUBS = 0x8;

/// section with only function pointers for initialization
pub const S_MOD_INIT_FUNC_POINTERS = 0x9;

/// section with only function pointers for termination
pub const S_MOD_TERM_FUNC_POINTERS = 0xa;

/// section contains symbols that are to be coalesced
pub const S_COALESCED = 0xb;

/// zero fill on demand section (that can be larger than 4 gigabytes)
pub const S_GB_ZEROFILL = 0xc;

/// section with only pairs of function pointers for interposing
pub const S_INTERPOSING = 0xd;

/// section with only 16 byte literals
pub const S_16BYTE_LITERALS = 0xe;

/// section contains DTrace Object Format
pub const S_DTRACE_DOF = 0xf;

/// section with only lazy symbol pointers to lazy loaded dylibs
pub const S_LAZY_DYLIB_SYMBOL_POINTERS = 0x10;

// If a segment contains any sections marked with S_ATTR_DEBUG then all
// sections in that segment must have this attribute.  No section other than
// a section marked with this attribute may reference the contents of this
// section.  A section with this attribute may contain no symbols and must have
// a section type S_REGULAR.  The static linker will not copy section contents
// from sections with this attribute into its output file.  These sections
// generally contain DWARF debugging info.

/// a debug section
pub const S_ATTR_DEBUG = 0x02000000;

/// section contains only true machine instructions
pub const S_ATTR_PURE_INSTRUCTIONS = 0x80000000;

/// section contains coalesced symbols that are not to be in a ranlib
/// table of contents
pub const S_ATTR_NO_TOC = 0x40000000;

/// ok to strip static symbols in this section in files with the
/// MH_DYLDLINK flag
pub const S_ATTR_STRIP_STATIC_SYMS = 0x20000000;

/// no dead stripping
pub const S_ATTR_NO_DEAD_STRIP = 0x10000000;

/// blocks are live if they reference live blocks
pub const S_ATTR_LIVE_SUPPORT = 0x8000000;

/// used with i386 code stubs written on by dyld
pub const S_ATTR_SELF_MODIFYING_CODE = 0x4000000;

/// section contains some machine instructions
pub const S_ATTR_SOME_INSTRUCTIONS = 0x400;

/// section has external relocation entries
pub const S_ATTR_EXT_RELOC = 0x200;

/// section has local relocation entries
pub const S_ATTR_LOC_RELOC = 0x100;

pub const cpu_type_t = integer_t;
pub const cpu_subtype_t = integer_t;
pub const integer_t = c_int;
pub const vm_prot_t = c_int;

/// CPU type targeting 64-bit Intel-based Macs
pub const CPU_TYPE_X86_64: cpu_type_t = 0x01000007;

/// CPU type targeting 64-bit ARM-based Macs
pub const CPU_TYPE_ARM64: cpu_type_t = 0x0100000C;

/// All Intel-based Macs
pub const CPU_SUBTYPE_X86_64_ALL: cpu_subtype_t = 0x3;

/// All ARM-based Macs
pub const CPU_SUBTYPE_ARM_ALL: cpu_subtype_t = 0x0;

// Protection values defined as bits within the vm_prot_t type
/// No VM protection
pub const VM_PROT_NONE: vm_prot_t = 0x0;

/// VM read permission
pub const VM_PROT_READ: vm_prot_t = 0x1;

/// VM write permission
pub const VM_PROT_WRITE: vm_prot_t = 0x2;

/// VM execute permission
pub const VM_PROT_EXECUTE: vm_prot_t = 0x4;

pub const reloc_type_x86_64 = packed enum(u4) {
    /// for absolute addresses
    X86_64_RELOC_UNSIGNED = 0,

    /// for signed 32-bit displacement
    X86_64_RELOC_SIGNED,

    /// a CALL/JMP instruction with 32-bit displacement
    X86_64_RELOC_BRANCH,

    /// a MOVQ load of a GOT entry
    X86_64_RELOC_GOT_LOAD,

    /// other GOT references
    X86_64_RELOC_GOT,

    /// must be followed by a X86_64_RELOC_UNSIGNED
    X86_64_RELOC_SUBTRACTOR,

    /// for signed 32-bit displacement with a -1 addend
    X86_64_RELOC_SIGNED_1,

    /// for signed 32-bit displacement with a -2 addend
    X86_64_RELOC_SIGNED_2,

    /// for signed 32-bit displacement with a -4 addend
    X86_64_RELOC_SIGNED_4,

    /// for thread local variables
    X86_64_RELOC_TLV,
};