825 lines
32 KiB
Zig
825 lines
32 KiB
Zig
const std = @import("std");
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const mem = std.mem;
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const assert = std.debug.assert;
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const Allocator = std.mem.Allocator;
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const ir = @import("ir.zig");
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const fs = std.fs;
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const elf = std.elf;
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const codegen = @import("codegen.zig");
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/// On common systems with a 0o022 umask, 0o777 will still result in a file created
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/// with 0o755 permissions, but it works appropriately if the system is configured
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/// more leniently. As another data point, C's fopen seems to open files with the
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/// 666 mode.
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const executable_mode = if (std.Target.current.os.tag == .windows) 0 else 0o777;
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const default_entry_addr = 0x8000000;
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pub const ErrorMsg = struct {
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byte_offset: usize,
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msg: []const u8,
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};
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pub const Result = struct {
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errors: []ErrorMsg,
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pub fn deinit(self: *Result, allocator: *mem.Allocator) void {
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for (self.errors) |err| {
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allocator.free(err.msg);
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}
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allocator.free(self.errors);
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self.* = undefined;
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}
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};
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/// Attempts incremental linking, if the file already exists.
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/// If incremental linking fails, falls back to truncating the file and rewriting it.
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/// A malicious file is detected as incremental link failure and does not cause Illegal Behavior.
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/// This operation is not atomic.
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pub fn updateExecutableFilePath(
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allocator: *Allocator,
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module: ir.Module,
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dir: fs.Dir,
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sub_path: []const u8,
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) !Result {
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const file = try dir.createFile(sub_path, .{ .truncate = false, .read = true, .mode = executable_mode });
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defer file.close();
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return updateExecutableFile(allocator, module, file);
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}
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/// Atomically overwrites the old file, if present.
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pub fn writeExecutableFilePath(
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allocator: *Allocator,
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module: ir.Module,
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dir: fs.Dir,
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sub_path: []const u8,
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) !Result {
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const af = try dir.atomicFile(sub_path, .{ .mode = executable_mode });
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defer af.deinit();
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const result = try writeExecutableFile(allocator, module, af.file);
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try af.finish();
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return result;
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}
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/// Attempts incremental linking, if the file already exists.
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/// If incremental linking fails, falls back to truncating the file and rewriting it.
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/// Returns an error if `file` is not already open with +read +write +seek abilities.
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/// A malicious file is detected as incremental link failure and does not cause Illegal Behavior.
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/// This operation is not atomic.
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pub fn updateExecutableFile(allocator: *Allocator, module: ir.Module, file: fs.File) !Result {
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return updateExecutableFileInner(allocator, module, file) catch |err| switch (err) {
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error.IncrFailed => {
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return writeExecutableFile(allocator, module, file);
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},
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else => |e| return e,
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};
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}
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const Update = struct {
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file: fs.File,
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module: *const ir.Module,
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/// Stored in native-endian format, depending on target endianness needs to be bswapped on read/write.
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/// Same order as in the file.
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sections: std.ArrayList(elf.Elf64_Shdr),
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shdr_table_offset: ?u64,
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/// Stored in native-endian format, depending on target endianness needs to be bswapped on read/write.
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/// Same order as in the file.
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program_headers: std.ArrayList(elf.Elf64_Phdr),
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phdr_table_offset: ?u64,
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/// The index into the program headers of a PT_LOAD program header with Read and Execute flags
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phdr_load_re_index: ?u16,
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entry_addr: ?u64,
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shstrtab: std.ArrayList(u8),
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shstrtab_index: ?u16,
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text_section_index: ?u16,
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symtab_section_index: ?u16,
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/// The same order as in the file
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symbols: std.ArrayList(elf.Elf64_Sym),
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errors: std.ArrayList(ErrorMsg),
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fn deinit(self: *Update) void {
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self.sections.deinit();
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self.program_headers.deinit();
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self.shstrtab.deinit();
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self.symbols.deinit();
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self.errors.deinit();
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}
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// `expand_num / expand_den` is the factor of padding when allocation
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const alloc_num = 4;
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const alloc_den = 3;
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/// Returns end pos of collision, if any.
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fn detectAllocCollision(self: *Update, start: u64, size: u64) ?u64 {
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const small_ptr = self.module.target.cpu.arch.ptrBitWidth() == 32;
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const ehdr_size: u64 = if (small_ptr) @sizeOf(elf.Elf32_Ehdr) else @sizeOf(elf.Elf64_Ehdr);
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if (start < ehdr_size)
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return ehdr_size;
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const end = start + satMul(size, alloc_num) / alloc_den;
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if (self.shdr_table_offset) |off| {
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const shdr_size: u64 = if (small_ptr) @sizeOf(elf.Elf32_Shdr) else @sizeOf(elf.Elf64_Shdr);
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const tight_size = self.sections.items.len * shdr_size;
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const increased_size = satMul(tight_size, alloc_num) / alloc_den;
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const test_end = off + increased_size;
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if (end > off and start < test_end) {
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return test_end;
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}
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}
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if (self.phdr_table_offset) |off| {
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const phdr_size: u64 = if (small_ptr) @sizeOf(elf.Elf32_Phdr) else @sizeOf(elf.Elf64_Phdr);
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const tight_size = self.sections.items.len * phdr_size;
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const increased_size = satMul(tight_size, alloc_num) / alloc_den;
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const test_end = off + increased_size;
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if (end > off and start < test_end) {
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return test_end;
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}
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}
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for (self.sections.items) |section| {
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const increased_size = satMul(section.sh_size, alloc_num) / alloc_den;
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const test_end = section.sh_offset + increased_size;
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if (end > section.sh_offset and start < test_end) {
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return test_end;
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}
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}
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for (self.program_headers.items) |program_header| {
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const increased_size = satMul(program_header.p_filesz, alloc_num) / alloc_den;
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const test_end = program_header.p_offset + increased_size;
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if (end > program_header.p_offset and start < test_end) {
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return test_end;
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}
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}
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return null;
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}
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fn allocatedSize(self: *Update, start: u64) u64 {
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var min_pos: u64 = std.math.maxInt(u64);
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if (self.shdr_table_offset) |off| {
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if (off > start and off < min_pos) min_pos = off;
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}
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if (self.phdr_table_offset) |off| {
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if (off > start and off < min_pos) min_pos = off;
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}
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for (self.sections.items) |section| {
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if (section.sh_offset <= start) continue;
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if (section.sh_offset < min_pos) min_pos = section.sh_offset;
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}
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for (self.program_headers.items) |program_header| {
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if (program_header.p_offset <= start) continue;
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if (program_header.p_offset < min_pos) min_pos = program_header.p_offset;
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}
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return min_pos - start;
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}
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fn findFreeSpace(self: *Update, object_size: u64, min_alignment: u16) u64 {
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var start: u64 = 0;
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while (self.detectAllocCollision(start, object_size)) |item_end| {
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start = mem.alignForwardGeneric(u64, item_end, min_alignment);
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}
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return start;
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}
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fn makeString(self: *Update, bytes: []const u8) !u32 {
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const result = self.shstrtab.items.len;
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try self.shstrtab.appendSlice(bytes);
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try self.shstrtab.append(0);
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return @intCast(u32, result);
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}
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fn perform(self: *Update) !void {
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const ptr_width: enum { p32, p64 } = switch (self.module.target.cpu.arch.ptrBitWidth()) {
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32 => .p32,
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64 => .p64,
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else => return error.UnsupportedArchitecture,
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};
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const small_ptr = switch (ptr_width) {
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.p32 => true,
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.p64 => false,
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};
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// This means the entire read-only executable program code needs to be rewritten.
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var phdr_load_re_dirty = false;
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var phdr_table_dirty = false;
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var shdr_table_dirty = false;
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var shstrtab_dirty = false;
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var symtab_dirty = false;
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if (self.phdr_load_re_index == null) {
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self.phdr_load_re_index = @intCast(u16, self.program_headers.items.len);
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const file_size = 256 * 1024;
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const p_align = 0x1000;
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const off = self.findFreeSpace(file_size, p_align);
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//std.debug.warn("found PT_LOAD free space 0x{x} to 0x{x}\n", .{ off, off + file_size });
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try self.program_headers.append(.{
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.p_type = elf.PT_LOAD,
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.p_offset = off,
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.p_filesz = file_size,
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.p_vaddr = default_entry_addr,
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.p_paddr = default_entry_addr,
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.p_memsz = 0,
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.p_align = p_align,
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.p_flags = elf.PF_X | elf.PF_R,
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});
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self.entry_addr = null;
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phdr_load_re_dirty = true;
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phdr_table_dirty = true;
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}
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if (self.sections.items.len == 0) {
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// There must always be a null section in index 0
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try self.sections.append(.{
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.sh_name = 0,
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.sh_type = elf.SHT_NULL,
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.sh_flags = 0,
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.sh_addr = 0,
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.sh_offset = 0,
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.sh_size = 0,
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.sh_link = 0,
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.sh_info = 0,
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.sh_addralign = 0,
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.sh_entsize = 0,
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});
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shdr_table_dirty = true;
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}
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if (self.shstrtab_index == null) {
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self.shstrtab_index = @intCast(u16, self.sections.items.len);
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assert(self.shstrtab.items.len == 0);
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try self.shstrtab.append(0); // need a 0 at position 0
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const off = self.findFreeSpace(self.shstrtab.items.len, 1);
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//std.debug.warn("found shstrtab free space 0x{x} to 0x{x}\n", .{ off, off + self.shstrtab.items.len });
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try self.sections.append(.{
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.sh_name = try self.makeString(".shstrtab"),
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.sh_type = elf.SHT_STRTAB,
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.sh_flags = 0,
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.sh_addr = 0,
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.sh_offset = off,
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.sh_size = self.shstrtab.items.len,
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.sh_link = 0,
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.sh_info = 0,
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.sh_addralign = 1,
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.sh_entsize = 0,
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});
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shstrtab_dirty = true;
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shdr_table_dirty = true;
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}
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if (self.text_section_index == null) {
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self.text_section_index = @intCast(u16, self.sections.items.len);
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const phdr = &self.program_headers.items[self.phdr_load_re_index.?];
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try self.sections.append(.{
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.sh_name = try self.makeString(".text"),
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.sh_type = elf.SHT_PROGBITS,
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.sh_flags = elf.SHF_ALLOC | elf.SHF_EXECINSTR,
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.sh_addr = phdr.p_vaddr,
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.sh_offset = phdr.p_offset,
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.sh_size = phdr.p_filesz,
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.sh_link = 0,
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.sh_info = 0,
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.sh_addralign = phdr.p_align,
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.sh_entsize = 0,
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});
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shdr_table_dirty = true;
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}
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if (self.symtab_section_index == null) {
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self.symtab_section_index = @intCast(u16, self.sections.items.len);
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const min_align: u16 = if (small_ptr) @alignOf(elf.Elf32_Sym) else @alignOf(elf.Elf64_Sym);
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const each_size: u64 = if (small_ptr) @sizeOf(elf.Elf32_Sym) else @sizeOf(elf.Elf64_Sym);
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const file_size = self.module.exports.len * each_size;
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const off = self.findFreeSpace(file_size, min_align);
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//std.debug.warn("found symtab free space 0x{x} to 0x{x}\n", .{ off, off + file_size });
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try self.sections.append(.{
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.sh_name = try self.makeString(".symtab"),
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.sh_type = elf.SHT_SYMTAB,
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.sh_flags = 0,
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.sh_addr = 0,
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.sh_offset = off,
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.sh_size = file_size,
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// The section header index of the associated string table.
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.sh_link = self.shstrtab_index.?,
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.sh_info = @intCast(u32, self.module.exports.len),
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.sh_addralign = min_align,
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.sh_entsize = each_size,
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});
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symtab_dirty = true;
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shdr_table_dirty = true;
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}
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const shsize: u64 = switch (ptr_width) {
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.p32 => @sizeOf(elf.Elf32_Shdr),
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.p64 => @sizeOf(elf.Elf64_Shdr),
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};
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const shalign: u16 = switch (ptr_width) {
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.p32 => @alignOf(elf.Elf32_Shdr),
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.p64 => @alignOf(elf.Elf64_Shdr),
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};
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if (self.shdr_table_offset == null) {
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self.shdr_table_offset = self.findFreeSpace(self.sections.items.len * shsize, shalign);
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shdr_table_dirty = true;
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}
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const phsize: u64 = switch (ptr_width) {
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.p32 => @sizeOf(elf.Elf32_Phdr),
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.p64 => @sizeOf(elf.Elf64_Phdr),
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};
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const phalign: u16 = switch (ptr_width) {
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.p32 => @alignOf(elf.Elf32_Phdr),
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.p64 => @alignOf(elf.Elf64_Phdr),
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};
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if (self.phdr_table_offset == null) {
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self.phdr_table_offset = self.findFreeSpace(self.program_headers.items.len * phsize, phalign);
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phdr_table_dirty = true;
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}
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const foreign_endian = self.module.target.cpu.arch.endian() != std.Target.current.cpu.arch.endian();
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try self.writeCodeAndSymbols(phdr_table_dirty, shdr_table_dirty);
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if (phdr_table_dirty) {
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const allocated_size = self.allocatedSize(self.phdr_table_offset.?);
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const needed_size = self.program_headers.items.len * phsize;
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if (needed_size > allocated_size) {
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self.phdr_table_offset = null; // free the space
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self.phdr_table_offset = self.findFreeSpace(needed_size, phalign);
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}
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const allocator = self.program_headers.allocator;
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switch (ptr_width) {
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.p32 => {
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const buf = try allocator.alloc(elf.Elf32_Phdr, self.program_headers.items.len);
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defer allocator.free(buf);
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for (buf) |*phdr, i| {
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phdr.* = progHeaderTo32(self.program_headers.items[i]);
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if (foreign_endian) {
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bswapAllFields(elf.Elf32_Phdr, phdr);
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}
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}
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try self.file.pwriteAll(mem.sliceAsBytes(buf), self.phdr_table_offset.?);
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},
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.p64 => {
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const buf = try allocator.alloc(elf.Elf64_Phdr, self.program_headers.items.len);
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defer allocator.free(buf);
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for (buf) |*phdr, i| {
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phdr.* = self.program_headers.items[i];
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if (foreign_endian) {
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bswapAllFields(elf.Elf64_Phdr, phdr);
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}
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}
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try self.file.pwriteAll(mem.sliceAsBytes(buf), self.phdr_table_offset.?);
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},
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}
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}
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{
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const shstrtab_sect = &self.sections.items[self.shstrtab_index.?];
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if (shstrtab_dirty or self.shstrtab.items.len != shstrtab_sect.sh_size) {
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const allocated_size = self.allocatedSize(shstrtab_sect.sh_offset);
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const needed_size = self.shstrtab.items.len;
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if (needed_size > allocated_size) {
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shstrtab_sect.sh_size = 0; // free the space
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shstrtab_sect.sh_offset = self.findFreeSpace(needed_size, 1);
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}
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shstrtab_sect.sh_size = needed_size;
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//std.debug.warn("shstrtab start=0x{x} end=0x{x}\n", .{ shstrtab_sect.sh_offset, shstrtab_sect.sh_offset + needed_size });
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try self.file.pwriteAll(self.shstrtab.items, shstrtab_sect.sh_offset);
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if (!shdr_table_dirty) {
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// Then it won't get written with the others and we need to do it.
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try self.writeSectHeader(self.shstrtab_index.?);
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}
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}
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}
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if (shdr_table_dirty) {
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const allocated_size = self.allocatedSize(self.shdr_table_offset.?);
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const needed_size = self.sections.items.len * phsize;
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if (needed_size > allocated_size) {
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self.shdr_table_offset = null; // free the space
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self.shdr_table_offset = self.findFreeSpace(needed_size, phalign);
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}
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const allocator = self.sections.allocator;
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switch (ptr_width) {
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.p32 => {
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const buf = try allocator.alloc(elf.Elf32_Shdr, self.sections.items.len);
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defer allocator.free(buf);
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for (buf) |*shdr, i| {
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shdr.* = sectHeaderTo32(self.sections.items[i]);
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if (foreign_endian) {
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bswapAllFields(elf.Elf32_Shdr, shdr);
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}
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}
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try self.file.pwriteAll(mem.sliceAsBytes(buf), self.shdr_table_offset.?);
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},
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.p64 => {
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const buf = try allocator.alloc(elf.Elf64_Shdr, self.sections.items.len);
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defer allocator.free(buf);
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for (buf) |*shdr, i| {
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shdr.* = self.sections.items[i];
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//std.debug.warn("writing section {}\n", .{shdr.*});
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if (foreign_endian) {
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bswapAllFields(elf.Elf64_Shdr, shdr);
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}
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}
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try self.file.pwriteAll(mem.sliceAsBytes(buf), self.shdr_table_offset.?);
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},
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}
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}
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if (self.entry_addr == null) {
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const msg = try std.fmt.allocPrint(self.errors.allocator, "no entry point found", .{});
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errdefer self.errors.allocator.free(msg);
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try self.errors.append(.{
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.byte_offset = 0,
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|
.msg = msg,
|
|
});
|
|
} else {
|
|
try self.writeElfHeader();
|
|
}
|
|
// TODO find end pos and truncate
|
|
}
|
|
|
|
fn writeElfHeader(self: *Update) !void {
|
|
var hdr_buf: [@sizeOf(elf.Elf64_Ehdr)]u8 = undefined;
|
|
|
|
var index: usize = 0;
|
|
hdr_buf[0..4].* = "\x7fELF".*;
|
|
index += 4;
|
|
|
|
const ptr_width: enum { p32, p64 } = switch (self.module.target.cpu.arch.ptrBitWidth()) {
|
|
32 => .p32,
|
|
64 => .p64,
|
|
else => return error.UnsupportedArchitecture,
|
|
};
|
|
hdr_buf[index] = switch (ptr_width) {
|
|
.p32 => elf.ELFCLASS32,
|
|
.p64 => elf.ELFCLASS64,
|
|
};
|
|
index += 1;
|
|
|
|
const endian = self.module.target.cpu.arch.endian();
|
|
hdr_buf[index] = switch (endian) {
|
|
.Little => elf.ELFDATA2LSB,
|
|
.Big => elf.ELFDATA2MSB,
|
|
};
|
|
index += 1;
|
|
|
|
hdr_buf[index] = 1; // ELF version
|
|
index += 1;
|
|
|
|
// OS ABI, often set to 0 regardless of target platform
|
|
// ABI Version, possibly used by glibc but not by static executables
|
|
// padding
|
|
mem.set(u8, hdr_buf[index..][0..9], 0);
|
|
index += 9;
|
|
|
|
assert(index == 16);
|
|
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], @enumToInt(elf.ET.EXEC), endian);
|
|
index += 2;
|
|
|
|
const machine = self.module.target.cpu.arch.toElfMachine();
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], @enumToInt(machine), endian);
|
|
index += 2;
|
|
|
|
// ELF Version, again
|
|
mem.writeInt(u32, hdr_buf[index..][0..4], 1, endian);
|
|
index += 4;
|
|
|
|
switch (ptr_width) {
|
|
.p32 => {
|
|
// e_entry
|
|
mem.writeInt(u32, hdr_buf[index..][0..4], @intCast(u32, self.entry_addr.?), endian);
|
|
index += 4;
|
|
|
|
// e_phoff
|
|
mem.writeInt(u32, hdr_buf[index..][0..4], @intCast(u32, self.phdr_table_offset.?), endian);
|
|
index += 4;
|
|
|
|
// e_shoff
|
|
mem.writeInt(u32, hdr_buf[index..][0..4], @intCast(u32, self.shdr_table_offset.?), endian);
|
|
index += 4;
|
|
},
|
|
.p64 => {
|
|
// e_entry
|
|
mem.writeInt(u64, hdr_buf[index..][0..8], self.entry_addr.?, endian);
|
|
index += 8;
|
|
|
|
// e_phoff
|
|
mem.writeInt(u64, hdr_buf[index..][0..8], self.phdr_table_offset.?, endian);
|
|
index += 8;
|
|
|
|
// e_shoff
|
|
mem.writeInt(u64, hdr_buf[index..][0..8], self.shdr_table_offset.?, endian);
|
|
index += 8;
|
|
},
|
|
}
|
|
|
|
const e_flags = 0;
|
|
mem.writeInt(u32, hdr_buf[index..][0..4], e_flags, endian);
|
|
index += 4;
|
|
|
|
const e_ehsize: u16 = switch (ptr_width) {
|
|
.p32 => @sizeOf(elf.Elf32_Ehdr),
|
|
.p64 => @sizeOf(elf.Elf64_Ehdr),
|
|
};
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], e_ehsize, endian);
|
|
index += 2;
|
|
|
|
const e_phentsize: u16 = switch (ptr_width) {
|
|
.p32 => @sizeOf(elf.Elf32_Phdr),
|
|
.p64 => @sizeOf(elf.Elf64_Phdr),
|
|
};
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], e_phentsize, endian);
|
|
index += 2;
|
|
|
|
const e_phnum = @intCast(u16, self.program_headers.items.len);
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], e_phnum, endian);
|
|
index += 2;
|
|
|
|
const e_shentsize: u16 = switch (ptr_width) {
|
|
.p32 => @sizeOf(elf.Elf32_Shdr),
|
|
.p64 => @sizeOf(elf.Elf64_Shdr),
|
|
};
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], e_shentsize, endian);
|
|
index += 2;
|
|
|
|
const e_shnum = @intCast(u16, self.sections.items.len);
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], e_shnum, endian);
|
|
index += 2;
|
|
|
|
mem.writeInt(u16, hdr_buf[index..][0..2], self.shstrtab_index.?, endian);
|
|
index += 2;
|
|
|
|
assert(index == e_ehsize);
|
|
|
|
try self.file.pwriteAll(hdr_buf[0..index], 0);
|
|
}
|
|
|
|
fn writeCodeAndSymbols(self: *Update, phdr_table_dirty: bool, shdr_table_dirty: bool) !void {
|
|
// index 0 is always a null symbol
|
|
try self.symbols.resize(1);
|
|
self.symbols.items[0] = .{
|
|
.st_name = 0,
|
|
.st_info = 0,
|
|
.st_other = 0,
|
|
.st_shndx = 0,
|
|
.st_value = 0,
|
|
.st_size = 0,
|
|
};
|
|
|
|
const phdr = &self.program_headers.items[self.phdr_load_re_index.?];
|
|
var vaddr: u64 = phdr.p_vaddr;
|
|
var file_off: u64 = phdr.p_offset;
|
|
|
|
var code = std.ArrayList(u8).init(self.sections.allocator);
|
|
defer code.deinit();
|
|
|
|
for (self.module.exports) |exp| {
|
|
code.shrink(0);
|
|
var symbol = try codegen.generateSymbol(exp.typed_value, self.module.*, &code);
|
|
defer symbol.deinit(code.allocator);
|
|
if (symbol.errors.len != 0) {
|
|
for (symbol.errors) |err| {
|
|
const msg = try mem.dupe(self.errors.allocator, u8, err.msg);
|
|
errdefer self.errors.allocator.free(msg);
|
|
try self.errors.append(.{
|
|
.byte_offset = err.byte_offset,
|
|
.msg = msg,
|
|
});
|
|
}
|
|
continue;
|
|
}
|
|
try self.file.pwriteAll(code.items, file_off);
|
|
|
|
if (mem.eql(u8, exp.name, "_start")) {
|
|
self.entry_addr = vaddr;
|
|
}
|
|
(try self.symbols.addOne()).* = .{
|
|
.st_name = try self.makeString(exp.name),
|
|
.st_info = (elf.STB_LOCAL << 4) | elf.STT_FUNC,
|
|
.st_other = 0,
|
|
.st_shndx = self.text_section_index.?,
|
|
.st_value = vaddr,
|
|
.st_size = code.items.len,
|
|
};
|
|
vaddr += code.items.len;
|
|
}
|
|
|
|
{
|
|
// Now that we know the code size, we need to update the program header for executable code
|
|
phdr.p_memsz = vaddr - phdr.p_vaddr;
|
|
phdr.p_filesz = phdr.p_memsz;
|
|
|
|
const shdr = &self.sections.items[self.text_section_index.?];
|
|
shdr.sh_size = phdr.p_filesz;
|
|
|
|
if (!phdr_table_dirty) {
|
|
// Then it won't get written with the others and we need to do it.
|
|
try self.writeProgHeader(self.phdr_load_re_index.?);
|
|
}
|
|
if (!shdr_table_dirty) {
|
|
// Then it won't get written with the others and we need to do it.
|
|
try self.writeSectHeader(self.text_section_index.?);
|
|
}
|
|
}
|
|
|
|
return self.writeSymbols();
|
|
}
|
|
|
|
fn writeProgHeader(self: *Update, index: usize) !void {
|
|
const foreign_endian = self.module.target.cpu.arch.endian() != std.Target.current.cpu.arch.endian();
|
|
const offset = self.program_headers.items[index].p_offset;
|
|
switch (self.module.target.cpu.arch.ptrBitWidth()) {
|
|
32 => {
|
|
var phdr = [1]elf.Elf32_Phdr{progHeaderTo32(self.program_headers.items[index])};
|
|
if (foreign_endian) {
|
|
bswapAllFields(elf.Elf32_Phdr, &phdr[0]);
|
|
}
|
|
return self.file.pwriteAll(mem.sliceAsBytes(&phdr), offset);
|
|
},
|
|
64 => {
|
|
var phdr = [1]elf.Elf64_Phdr{self.program_headers.items[index]};
|
|
if (foreign_endian) {
|
|
bswapAllFields(elf.Elf64_Phdr, &phdr[0]);
|
|
}
|
|
return self.file.pwriteAll(mem.sliceAsBytes(&phdr), offset);
|
|
},
|
|
else => return error.UnsupportedArchitecture,
|
|
}
|
|
}
|
|
|
|
fn writeSectHeader(self: *Update, index: usize) !void {
|
|
const foreign_endian = self.module.target.cpu.arch.endian() != std.Target.current.cpu.arch.endian();
|
|
const offset = self.sections.items[index].sh_offset;
|
|
switch (self.module.target.cpu.arch.ptrBitWidth()) {
|
|
32 => {
|
|
var shdr: [1]elf.Elf32_Shdr = undefined;
|
|
shdr[0] = sectHeaderTo32(self.sections.items[index]);
|
|
if (foreign_endian) {
|
|
bswapAllFields(elf.Elf32_Shdr, &shdr[0]);
|
|
}
|
|
return self.file.pwriteAll(mem.sliceAsBytes(&shdr), offset);
|
|
},
|
|
64 => {
|
|
var shdr = [1]elf.Elf64_Shdr{self.sections.items[index]};
|
|
if (foreign_endian) {
|
|
bswapAllFields(elf.Elf64_Shdr, &shdr[0]);
|
|
}
|
|
return self.file.pwriteAll(mem.sliceAsBytes(&shdr), offset);
|
|
},
|
|
else => return error.UnsupportedArchitecture,
|
|
}
|
|
}
|
|
|
|
fn writeSymbols(self: *Update) !void {
|
|
const ptr_width: enum { p32, p64 } = switch (self.module.target.cpu.arch.ptrBitWidth()) {
|
|
32 => .p32,
|
|
64 => .p64,
|
|
else => return error.UnsupportedArchitecture,
|
|
};
|
|
const small_ptr = ptr_width == .p32;
|
|
const syms_sect = &self.sections.items[self.symtab_section_index.?];
|
|
const sym_align: u16 = if (small_ptr) @alignOf(elf.Elf32_Sym) else @alignOf(elf.Elf64_Sym);
|
|
const sym_size: u64 = if (small_ptr) @sizeOf(elf.Elf32_Sym) else @sizeOf(elf.Elf64_Sym);
|
|
|
|
const allocated_size = self.allocatedSize(syms_sect.sh_offset);
|
|
const needed_size = self.symbols.items.len * sym_size;
|
|
if (needed_size > allocated_size) {
|
|
syms_sect.sh_size = 0; // free the space
|
|
syms_sect.sh_offset = self.findFreeSpace(needed_size, sym_align);
|
|
//std.debug.warn("moved symtab to 0x{x} to 0x{x}\n", .{ syms_sect.sh_offset, syms_sect.sh_offset + needed_size });
|
|
}
|
|
//std.debug.warn("symtab start=0x{x} end=0x{x}\n", .{ syms_sect.sh_offset, syms_sect.sh_offset + needed_size });
|
|
syms_sect.sh_size = needed_size;
|
|
syms_sect.sh_info = @intCast(u32, self.symbols.items.len);
|
|
const allocator = self.symbols.allocator;
|
|
const foreign_endian = self.module.target.cpu.arch.endian() != std.Target.current.cpu.arch.endian();
|
|
switch (ptr_width) {
|
|
.p32 => {
|
|
const buf = try allocator.alloc(elf.Elf32_Sym, self.symbols.items.len);
|
|
defer allocator.free(buf);
|
|
|
|
for (buf) |*sym, i| {
|
|
sym.* = .{
|
|
.st_name = self.symbols.items[i].st_name,
|
|
.st_value = @intCast(u32, self.symbols.items[i].st_value),
|
|
.st_size = @intCast(u32, self.symbols.items[i].st_size),
|
|
.st_info = self.symbols.items[i].st_info,
|
|
.st_other = self.symbols.items[i].st_other,
|
|
.st_shndx = self.symbols.items[i].st_shndx,
|
|
};
|
|
if (foreign_endian) {
|
|
bswapAllFields(elf.Elf32_Sym, sym);
|
|
}
|
|
}
|
|
try self.file.pwriteAll(mem.sliceAsBytes(buf), syms_sect.sh_offset);
|
|
},
|
|
.p64 => {
|
|
const buf = try allocator.alloc(elf.Elf64_Sym, self.symbols.items.len);
|
|
defer allocator.free(buf);
|
|
|
|
for (buf) |*sym, i| {
|
|
sym.* = .{
|
|
.st_name = self.symbols.items[i].st_name,
|
|
.st_value = self.symbols.items[i].st_value,
|
|
.st_size = self.symbols.items[i].st_size,
|
|
.st_info = self.symbols.items[i].st_info,
|
|
.st_other = self.symbols.items[i].st_other,
|
|
.st_shndx = self.symbols.items[i].st_shndx,
|
|
};
|
|
if (foreign_endian) {
|
|
bswapAllFields(elf.Elf64_Sym, sym);
|
|
}
|
|
}
|
|
try self.file.pwriteAll(mem.sliceAsBytes(buf), syms_sect.sh_offset);
|
|
},
|
|
}
|
|
}
|
|
};
|
|
|
|
/// Truncates the existing file contents and overwrites the contents.
|
|
/// Returns an error if `file` is not already open with +read +write +seek abilities.
|
|
pub fn writeExecutableFile(allocator: *Allocator, module: ir.Module, file: fs.File) !Result {
|
|
var update = Update{
|
|
.file = file,
|
|
.module = &module,
|
|
.sections = std.ArrayList(elf.Elf64_Shdr).init(allocator),
|
|
.shdr_table_offset = null,
|
|
.program_headers = std.ArrayList(elf.Elf64_Phdr).init(allocator),
|
|
.phdr_table_offset = null,
|
|
.phdr_load_re_index = null,
|
|
.entry_addr = null,
|
|
.shstrtab = std.ArrayList(u8).init(allocator),
|
|
.shstrtab_index = null,
|
|
.text_section_index = null,
|
|
.symtab_section_index = null,
|
|
|
|
.symbols = std.ArrayList(elf.Elf64_Sym).init(allocator),
|
|
|
|
.errors = std.ArrayList(ErrorMsg).init(allocator),
|
|
};
|
|
defer update.deinit();
|
|
|
|
try update.perform();
|
|
return Result{
|
|
.errors = update.errors.toOwnedSlice(),
|
|
};
|
|
}
|
|
|
|
/// Returns error.IncrFailed if incremental update could not be performed.
|
|
fn updateExecutableFileInner(allocator: *Allocator, module: ir.Module, file: fs.File) !Result {
|
|
//var ehdr_buf: [@sizeOf(elf.Elf64_Ehdr)]u8 = undefined;
|
|
|
|
// TODO implement incremental linking
|
|
return error.IncrFailed;
|
|
}
|
|
|
|
/// Saturating multiplication
|
|
fn satMul(a: var, b: var) @TypeOf(a, b) {
|
|
const T = @TypeOf(a, b);
|
|
return std.math.mul(T, a, b) catch std.math.maxInt(T);
|
|
}
|
|
|
|
fn bswapAllFields(comptime S: type, ptr: *S) void {
|
|
@panic("TODO implement bswapAllFields");
|
|
}
|
|
|
|
fn progHeaderTo32(phdr: elf.Elf64_Phdr) elf.Elf32_Phdr {
|
|
return .{
|
|
.p_type = phdr.p_type,
|
|
.p_flags = phdr.p_flags,
|
|
.p_offset = @intCast(u32, phdr.p_offset),
|
|
.p_vaddr = @intCast(u32, phdr.p_vaddr),
|
|
.p_paddr = @intCast(u32, phdr.p_paddr),
|
|
.p_filesz = @intCast(u32, phdr.p_filesz),
|
|
.p_memsz = @intCast(u32, phdr.p_memsz),
|
|
.p_align = @intCast(u32, phdr.p_align),
|
|
};
|
|
}
|
|
|
|
fn sectHeaderTo32(shdr: elf.Elf64_Shdr) elf.Elf32_Shdr {
|
|
return .{
|
|
.sh_name = shdr.sh_name,
|
|
.sh_type = shdr.sh_type,
|
|
.sh_flags = @intCast(u32, shdr.sh_flags),
|
|
.sh_addr = @intCast(u32, shdr.sh_addr),
|
|
.sh_offset = @intCast(u32, shdr.sh_offset),
|
|
.sh_size = @intCast(u32, shdr.sh_size),
|
|
.sh_link = shdr.sh_link,
|
|
.sh_info = shdr.sh_info,
|
|
.sh_addralign = @intCast(u32, shdr.sh_addralign),
|
|
.sh_entsize = @intCast(u32, shdr.sh_entsize),
|
|
};
|
|
}
|