Commit e1cf2c8346
Changed files (1)
src
src/objcopy.zig
@@ -129,10 +129,6 @@ pub fn cmdObjCopy(
fatal("zig objcopy: ELF to RAW or HEX copying does not support --strip", .{});
if (opt_extract != null)
fatal("zig objcopy: ELF to RAW or HEX copying does not support --extract-to", .{});
- if (opt_extract != null)
- fatal("zig objcopy: ELF to RAW or HEX copying does not support --extract-to", .{});
- if (opt_extract != null)
- fatal("zig objcopy: ELF to RAW or HEX copying does not support --extract-to", .{});
try emitElf(arena, in_file, out_file, elf_hdr, .{
.ofmt = out_fmt,
@@ -658,7 +654,7 @@ test "containsValidAddressRange" {
// -------------
// ELF to ELF stripping
-pub const StripElfOptions = struct {
+const StripElfOptions = struct {
extract_to: ?[]const u8 = null,
add_debuglink: ?[]const u8 = null,
strip_all: bool = false,
@@ -673,72 +669,64 @@ fn stripElf(
elf_hdr: elf.Header,
options: StripElfOptions,
) !void {
- switch (elf_hdr.is_64) {
- inline else => |is_64| {
- const Elf = ElfContents(is_64);
- const Filter = Elf.Filter;
- const DebugLink = Elf.DebugLink;
-
- var elf_contents = try Elf.parse(allocator, in_file, elf_hdr);
- defer elf_contents.deinit();
-
- const filter: Filter = filter: {
- if (options.only_keep_debug) break :filter .debug;
- if (options.strip_all) break :filter .program;
- if (options.strip_debug) break :filter .program_and_symbols;
- break :filter .all;
+ const Filter = ElfFileHelper.Filter;
+ const DebugLink = ElfFileHelper.DebugLink;
+
+ const filter: Filter = filter: {
+ if (options.only_keep_debug) break :filter .debug;
+ if (options.strip_all) break :filter .program;
+ if (options.strip_debug) break :filter .program_and_symbols;
+ break :filter .all;
+ };
+
+ const filter_complement: ?Filter = blk: {
+ if (options.extract_to) |_| {
+ break :blk switch (filter) {
+ .program => .debug_and_symbols,
+ .debug => .program_and_symbols,
+ .program_and_symbols => .debug,
+ .debug_and_symbols => .program,
+ .all => fatal("zig objcopy: nothing to extract", .{}),
};
+ } else {
+ break :blk null;
+ }
+ };
+ const debuglink_path = path: {
+ if (options.add_debuglink) |path| break :path path;
+ if (options.extract_to) |path| break :path path;
+ break :path null;
+ };
- if (options.extract_to) |filename| {
- const dbg_file = std.fs.cwd().createFile(filename, .{}) catch |err| {
- fatal("zig objcopy: unable to create '{s}': {s}", .{ filename, @errorName(err) });
+ switch (elf_hdr.is_64) {
+ inline else => |is_64| {
+ var elf_file = try ElfFile(is_64).parse(allocator, in_file, elf_hdr);
+ defer elf_file.deinit();
+
+ if (filter_complement) |flt| {
+ // write the .dbg file and close it, so it can be read back to compute the debuglink checksum.
+ const path = options.extract_to.?;
+ const dbg_file = std.fs.cwd().createFile(path, .{}) catch |err| {
+ fatal("zig objcopy: unable to create '{s}': {s}", .{ path, @errorName(err) });
};
defer dbg_file.close();
- const filter_complement: Filter = switch (filter) {
- .program => .debug_and_symbols,
- .debug => .program_and_symbols,
- .program_and_symbols => .debug,
- .debug_and_symbols => .program,
- .all => fatal("zig objcopy: nothing to extract", .{}),
- };
-
- try elf_contents.emit(allocator, dbg_file, in_file, filter_complement, null);
+ try elf_file.emit(allocator, dbg_file, in_file, .{ .section_filter = flt });
}
- const debuglink: ?DebugLink = blk: {
- const debuglink_filename = name: {
- if (options.add_debuglink) |filename| break :name filename;
- if (options.extract_to) |filename| break :name filename;
- break :name null;
- };
- if (debuglink_filename) |filename| {
- const dbg_file = std.fs.cwd().openFile(filename, .{}) catch |err| {
- fatal("zig objcopy: could not read `{s}`: {s}\n", .{ filename, @errorName(err) });
- };
- defer dbg_file.close();
-
- break :blk .{
- .name = std.fs.path.basename(filename),
- .crc32 = try computeFileCrc(dbg_file),
- };
- } else {
- break :blk null;
- }
- };
-
- try elf_contents.emit(allocator, out_file, in_file, filter, debuglink);
+ const debuglink: ?DebugLink = if (debuglink_path) |path| ElfFileHelper.createDebugLink(path) else null;
+ try elf_file.emit(allocator, out_file, in_file, .{ .section_filter = filter, .debuglink = debuglink });
},
}
}
// note: this is "a minimal effort implementation"
// It doesn't support all possibile elf files: some sections type may need fixups, the program header may need fix up, ...
-// it was written for a specific use case (strip debug info to a sperate file, for linux 64-bits executables built with `zig` or `zig c++` )
-// It manupulates and reoders the sections as little as possible to avoid having to do fixups.
+// It was written for a specific use case (strip debug info to a sperate file, for linux 64-bits executables built with `zig` or `zig c++` )
+// It moves and reoders the sections as little as possible to avoid having to do fixups.
// TODO: support non-native endianess
-fn ElfContents(comptime is_64: bool) type {
+fn ElfFile(comptime is_64: bool) type {
const Elf_Ehdr = if (is_64) elf.Elf64_Ehdr else elf.Elf32_Ehdr;
const Elf_Phdr = if (is_64) elf.Elf64_Phdr else elf.Elf32_Phdr;
const Elf_Shdr = if (is_64) elf.Elf64_Shdr else elf.Elf32_Shdr;
@@ -752,27 +740,26 @@ fn ElfContents(comptime is_64: bool) type {
sections: []const Section,
arena: std.heap.ArenaAllocator,
+ const SectionCategory = ElfFileHelper.SectionCategory;
const section_memory_align = @alignOf(Elf_Sym); // most restrictive of what we may load in memory
const Section = struct {
section: Elf_Shdr,
name: []const u8 = "",
segment: ?*const Elf_Phdr = null, // if the section is used by a program segment (there can be more than one)
payload: ?[]align(section_memory_align) const u8 = null, // if we need the data in memory
- usage: Usage = .none, // should the section be kept in the exe or stripped to the debug database, or both.
-
- const Usage = enum { common, exe, debug, symbols, none };
+ category: SectionCategory = .none, // should the section be kept in the exe or stripped to the debug database, or both.
};
const Self = @This();
- pub fn parse(gpa: Allocator, source: File, header: elf.Header) !Self {
+ pub fn parse(gpa: Allocator, in_file: File, header: elf.Header) !Self {
var arena = std.heap.ArenaAllocator.init(gpa);
errdefer arena.deinit();
const allocator = arena.allocator();
var raw_header: Elf_Ehdr = undefined;
{
- const bytes_read = try source.preadAll(std.mem.asBytes(&raw_header), 0);
+ const bytes_read = try in_file.preadAll(std.mem.asBytes(&raw_header), 0);
if (bytes_read < @sizeOf(Elf_Ehdr))
return error.TRUNCATED_ELF;
}
@@ -783,7 +770,7 @@ fn ElfContents(comptime is_64: bool) type {
fatal("zig objcopy: unsuported ELF file, unexpected phentsize ({d})", .{header.phentsize});
const program_header = try allocator.alloc(Elf_Phdr, header.phnum);
- const bytes_read = try source.preadAll(std.mem.sliceAsBytes(program_header), header.phoff);
+ const bytes_read = try in_file.preadAll(std.mem.sliceAsBytes(program_header), header.phoff);
if (bytes_read < @sizeOf(Elf_Phdr) * header.phnum)
return error.TRUNCATED_ELF;
break :blk program_header;
@@ -798,7 +785,7 @@ fn ElfContents(comptime is_64: bool) type {
const raw_section_header = try allocator.alloc(Elf_Shdr, header.shnum);
defer allocator.free(raw_section_header);
- const bytes_read = try source.preadAll(std.mem.sliceAsBytes(raw_section_header), header.shoff);
+ const bytes_read = try in_file.preadAll(std.mem.sliceAsBytes(raw_section_header), header.shoff);
if (bytes_read < @sizeOf(Elf_Phdr) * header.shnum)
return error.TRUNCATED_ELF;
@@ -821,7 +808,7 @@ fn ElfContents(comptime is_64: bool) type {
if (need_data or need_strings) {
const buffer = try allocator.alignedAlloc(u8, section_memory_align, @intCast(usize, section.section.sh_size));
- const bytes_read = try source.preadAll(buffer, section.section.sh_offset);
+ const bytes_read = try in_file.preadAll(buffer, section.section.sh_offset);
if (bytes_read != section.section.sh_size) return error.TRUNCATED_ELF;
section.payload = buffer;
}
@@ -830,7 +817,7 @@ fn ElfContents(comptime is_64: bool) type {
// fill-in sections info:
// resolve the name
// find if a program segment uses the section
- // classify sections usage (used by program segments, debug datadase, common metadata, symbol table)
+ // categorise sections usage (used by program segments, debug datadase, common metadata, symbol table)
for (sections) |*section| {
section.segment = for (program_segments) |*seg| {
if (sectionWithinSegment(section.section, seg.*)) break seg;
@@ -839,65 +826,36 @@ fn ElfContents(comptime is_64: bool) type {
if (section.section.sh_name != 0 and header.shstrndx != elf.SHN_UNDEF)
section.name = std.mem.span(@ptrCast([*:0]const u8, §ions[header.shstrndx].payload.?[section.section.sh_name]));
- const usage_from_program: Section.Usage = if (section.segment != null) .exe else .debug;
- section.usage = switch (section.section.sh_type) {
+ const category_from_program: SectionCategory = if (section.segment != null) .exe else .debug;
+ section.category = switch (section.section.sh_type) {
elf.SHT_NOTE => .common,
elf.SHT_SYMTAB => .symbols, // "strip all" vs "strip only debug"
elf.SHT_DYNSYM => .exe,
- elf.SHT_PROGBITS => usage: {
- if (std.mem.eql(u8, section.name, ".comment")) break :usage .exe;
- if (std.mem.eql(u8, section.name, ".gnu_debuglink")) break :usage .none;
- break :usage usage_from_program;
+ elf.SHT_PROGBITS => cat: {
+ if (std.mem.eql(u8, section.name, ".comment")) break :cat .exe;
+ if (std.mem.eql(u8, section.name, ".gnu_debuglink")) break :cat .none;
+ break :cat category_from_program;
},
elf.SHT_LOPROC...elf.SHT_HIPROC => .common, // don't strip unkonwn sections
elf.SHT_LOUSER...elf.SHT_HIUSER => .common, // don't strip unkonwn sections
- else => usage_from_program,
+ else => category_from_program,
};
}
- sections[0].usage = .common; // mandatory null section
+ sections[0].category = .common; // mandatory null section
if (header.shstrndx != elf.SHN_UNDEF)
- sections[header.shstrndx].usage = .common; // string table for the headers
+ sections[header.shstrndx].category = .common; // string table for the headers
// recursive dependencies
var dirty: u1 = 1;
while (dirty != 0) {
dirty = 0;
- const Local = struct {
- fn propagateUsage(cur: *Section.Usage, new: Section.Usage) u1 {
- const use: Section.Usage = switch (cur.*) {
- .none => new,
- .common => .common,
- .debug => switch (new) {
- .none, .debug => .debug,
- else => new,
- },
- .exe => switch (new) {
- .common => .common,
- .none, .debug, .exe => .exe,
- .symbols => .exe,
- },
- .symbols => switch (new) {
- .none, .common, .debug, .exe => unreachable,
- .symbols => .symbols,
- },
- };
-
- if (cur.* != use) {
- cur.* = use;
- return 1;
- } else {
- return 0;
- }
- }
- };
-
for (sections) |*section| {
if (section.section.sh_link != elf.SHN_UNDEF)
- dirty |= Local.propagateUsage(§ions[section.section.sh_link].usage, section.usage);
+ dirty |= ElfFileHelper.propagateCategory(§ions[section.section.sh_link].category, section.category);
if ((section.section.sh_flags & elf.SHF_INFO_LINK) != 0 and section.section.sh_info != elf.SHN_UNDEF)
- dirty |= Local.propagateUsage(§ions[section.section.sh_info].usage, section.usage);
+ dirty |= ElfFileHelper.propagateCategory(§ions[section.section.sh_info].category, section.category);
if (section.payload) |data| {
switch (section.section.sh_type) {
@@ -906,7 +864,7 @@ fn ElfContents(comptime is_64: bool) type {
const defs = @ptrCast([*]const Elf_Verdef, data)[0 .. @intCast(usize, section.section.sh_size) / @sizeOf(Elf_Verdef)];
for (defs) |def| {
if (def.vd_ndx != elf.SHN_UNDEF)
- dirty |= Local.propagateUsage(§ions[def.vd_ndx].usage, section.usage);
+ dirty |= ElfFileHelper.propagateCategory(§ions[def.vd_ndx].category, section.category);
}
},
elf.SHT_SYMTAB, elf.SHT_DYNSYM => {
@@ -915,7 +873,7 @@ fn ElfContents(comptime is_64: bool) type {
for (syms) |sym| {
if (sym.st_shndx != elf.SHN_UNDEF and sym.st_shndx < elf.SHN_LORESERVE)
- dirty |= Local.propagateUsage(§ions[sym.st_shndx].usage, section.usage);
+ dirty |= ElfFileHelper.propagateCategory(§ions[sym.st_shndx].category, section.category);
}
},
else => {},
@@ -936,9 +894,13 @@ fn ElfContents(comptime is_64: bool) type {
self.arena.deinit();
}
- const DebugLink = struct { name: []const u8, crc32: u32 };
- const Filter = enum { all, program, debug, program_and_symbols, debug_and_symbols };
- fn emit(self: *const Self, gpa: Allocator, output: File, source: File, filter: Filter, debuglink: ?DebugLink) !void {
+ const Filter = ElfFileHelper.Filter;
+ const DebugLink = ElfFileHelper.DebugLink;
+ const EmitElfOptions = struct {
+ section_filter: Filter = .all,
+ debuglink: ?DebugLink = null,
+ };
+ fn emit(self: *const Self, gpa: Allocator, out_file: File, in_file: File, options: EmitElfOptions) !void {
var arena = std.heap.ArenaAllocator.init(gpa);
defer arena.deinit();
const allocator = arena.allocator();
@@ -950,63 +912,37 @@ fn ElfContents(comptime is_64: bool) type {
// the program header is kept unchanged. (`strip` does update it, but `eu-strip` does not, and it still works)
const Update = struct {
- action: enum { keep, strip, empty },
+ action: ElfFileHelper.Action,
// remap the indexs after omitting the filtered sections
remap_idx: u16,
// optionally overrides the payload from the source file
- payload: ?[]align(section_memory_align) const u8,
+ payload: ?[]align(section_memory_align) const u8 = null,
+ section: ?Elf_Shdr = null,
};
const sections_update = try allocator.alloc(Update, self.sections.len);
const new_shnum = blk: {
var next_idx: u16 = 0;
for (self.sections, sections_update) |section, *update| {
- update.action = action: {
- if (section.usage == .none) break :action .strip;
- break :action switch (filter) {
- .all => switch (section.usage) {
- .none => .strip,
- else => .keep,
- },
- .program => switch (section.usage) {
- .common, .exe => .keep,
- else => .strip,
- },
- .program_and_symbols => switch (section.usage) {
- .common, .exe, .symbols => .keep,
- else => .strip,
- },
- .debug => switch (section.usage) {
- .exe, .symbols => .empty,
- .none => .strip,
- else => .keep,
- },
- .debug_and_symbols => switch (section.usage) {
- .exe => .empty,
- .none => .strip,
- else => .keep,
- },
- };
- };
-
- if (update.action == .strip) {
- update.remap_idx = elf.SHN_UNDEF;
- } else {
- update.remap_idx = next_idx;
+ const action = ElfFileHelper.selectAction(section.category, options.section_filter);
+ const remap_idx = idx: {
+ if (action == .strip) break :idx elf.SHN_UNDEF;
next_idx += 1;
- }
-
- update.payload = null;
+ break :idx next_idx - 1;
+ };
+ update.* = Update{ .action = action, .remap_idx = remap_idx };
}
- if (debuglink != null)
+ if (options.debuglink != null)
next_idx += 1;
+
break :blk next_idx;
};
+ // add a ".gnu_debuglink" to the string table if needed
const debuglink_name: u32 = blk: {
- if (debuglink == null) break :blk elf.SHN_UNDEF;
+ if (options.debuglink == null) break :blk elf.SHN_UNDEF;
if (self.raw_elf_header.e_shstrndx == elf.SHN_UNDEF)
fatal("zig objcopy: no strtab, cannot add the debuglink section", .{}); // TODO add the section if needed?
@@ -1026,11 +962,7 @@ fn ElfContents(comptime is_64: bool) type {
break :blk new_offset;
};
- const WriteCmd = union(enum) {
- copy_range: struct { in_offset: u64, len: u64, out_offset: u64 },
- write_data: struct { data: []const u8, out_offset: u64 },
- };
- var cmdbuf = std.ArrayList(WriteCmd).init(allocator);
+ var cmdbuf = std.ArrayList(ElfFileHelper.WriteCmd).init(allocator);
defer cmdbuf.deinit();
try cmdbuf.ensureUnusedCapacity(3 + new_shnum);
var eof_offset: Elf_OffSize = 0; // track the end of the data written so far.
@@ -1076,8 +1008,9 @@ fn ElfContents(comptime is_64: bool) type {
if (update.action == .strip) continue;
std.debug.assert(update.remap_idx == dest_section_idx);
- const src = §ion.section;
+ const src = if (update.section) |*s| s else §ion.section;
const dest = &dest_sections[dest_section_idx];
+ const payload = if (update.payload) |data| data else section.payload;
dest_section_idx += 1;
dest.* = src.*;
@@ -1087,7 +1020,6 @@ fn ElfContents(comptime is_64: bool) type {
if ((src.sh_flags & elf.SHF_INFO_LINK) != 0 and src.sh_info != elf.SHN_UNDEF)
dest.sh_info = sections_update[src.sh_info].remap_idx;
- const payload = if (update.payload) |data| data else section.payload;
if (payload) |data|
dest.sh_size = @intCast(Elf_OffSize, data.len);
@@ -1108,29 +1040,36 @@ fn ElfContents(comptime is_64: bool) type {
if (dest.sh_type != elf.SHT_NOBITS) {
if (payload) |src_data| {
// update sections payload and write
- const data = try allocator.alignedAlloc(u8, section_memory_align, src_data.len);
- std.mem.copy(u8, data, src_data);
+ const dest_data = switch (src.sh_type) {
+ elf.DT_VERSYM => dst_data: {
+ const data = try allocator.alignedAlloc(u8, section_memory_align, src_data.len);
+ std.mem.copy(u8, data, src_data);
- switch (src.sh_type) {
- elf.DT_VERSYM => {
const defs = @ptrCast([*]Elf_Verdef, data)[0 .. @intCast(usize, src.sh_size) / @sizeOf(Elf_Verdef)];
for (defs) |*def| {
if (def.vd_ndx != elf.SHN_UNDEF)
def.vd_ndx = sections_update[src.sh_info].remap_idx;
}
+
+ break :dst_data data;
},
- elf.SHT_SYMTAB, elf.SHT_DYNSYM => {
+ elf.SHT_SYMTAB, elf.SHT_DYNSYM => dst_data: {
+ const data = try allocator.alignedAlloc(u8, section_memory_align, src_data.len);
+ std.mem.copy(u8, data, src_data);
+
const syms = @ptrCast([*]Elf_Sym, data)[0 .. @intCast(usize, src.sh_size) / @sizeOf(Elf_Sym)];
for (syms) |*sym| {
if (sym.st_shndx != elf.SHN_UNDEF and sym.st_shndx < elf.SHN_LORESERVE)
sym.st_shndx = sections_update[sym.st_shndx].remap_idx;
}
+
+ break :dst_data data;
},
- else => {},
- }
+ else => src_data,
+ };
- std.debug.assert(data.len == dest.sh_size);
- cmdbuf.appendAssumeCapacity(.{ .write_data = .{ .data = data, .out_offset = dest.sh_offset } });
+ std.debug.assert(dest_data.len == dest.sh_size);
+ cmdbuf.appendAssumeCapacity(.{ .write_data = .{ .data = dest_data, .out_offset = dest.sh_offset } });
eof_offset = dest.sh_offset + dest.sh_size;
} else {
// direct contents copy
@@ -1144,7 +1083,7 @@ fn ElfContents(comptime is_64: bool) type {
}
// add a ".gnu_debuglink" section
- if (debuglink) |link| {
+ if (options.debuglink) |link| {
const payload = payload: {
const crc_offset = std.mem.alignForward(link.name.len + 1, 4);
const buf = try allocator.alignedAlloc(u8, 4, crc_offset + 4);
@@ -1188,71 +1127,7 @@ fn ElfContents(comptime is_64: bool) type {
cmdbuf.appendAssumeCapacity(.{ .write_data = .{ .data = data, .out_offset = updated_elf_header.e_shoff } });
}
- // consolidate holes between writes:
- // by coping original padding data from in_file (by fusing contiguous ranges)
- // by writing zeroes otherwise
- const zeroes = [1]u8{0} ** 4096;
- const consolidated_cmdbuf = blk: {
- var newbuf = std.ArrayList(WriteCmd).init(allocator);
- try newbuf.ensureUnusedCapacity(cmdbuf.items.len * 2);
- var offset: u64 = 0;
- var fused_cmd: ?WriteCmd = null;
- for (cmdbuf.items) |cmd| {
- switch (cmd) {
- .write_data => |data| {
- std.debug.assert(data.out_offset >= offset);
- if (fused_cmd) |prev| {
- newbuf.appendAssumeCapacity(prev);
- fused_cmd = null;
- }
- if (data.out_offset > offset) {
- newbuf.appendAssumeCapacity(.{ .write_data = .{ .data = zeroes[0..@intCast(usize, data.out_offset - offset)], .out_offset = offset } });
- }
- newbuf.appendAssumeCapacity(cmd);
- offset = data.out_offset + data.data.len;
- },
- .copy_range => |range| {
- std.debug.assert(range.out_offset >= offset);
- if (fused_cmd) |prev| {
- if (range.in_offset >= prev.copy_range.in_offset + prev.copy_range.len and (range.out_offset - prev.copy_range.out_offset == range.in_offset - prev.copy_range.in_offset)) {
- fused_cmd = .{ .copy_range = .{
- .in_offset = prev.copy_range.in_offset,
- .out_offset = prev.copy_range.out_offset,
- .len = (range.out_offset + range.len) - prev.copy_range.out_offset,
- } };
- } else {
- newbuf.appendAssumeCapacity(prev);
- if (range.out_offset > offset) {
- newbuf.appendAssumeCapacity(.{ .write_data = .{ .data = zeroes[0..@intCast(usize, range.out_offset - offset)], .out_offset = offset } });
- }
- fused_cmd = cmd;
- }
- } else {
- fused_cmd = cmd;
- }
- offset = range.out_offset + range.len;
- },
- }
- }
- if (fused_cmd) |cmd| {
- newbuf.appendAssumeCapacity(cmd);
- }
- break :blk newbuf.items;
- };
-
- // write the output file
- for (consolidated_cmdbuf) |cmd| {
- switch (cmd) {
- .write_data => |data| {
- var iovec = [_]std.os.iovec_const{.{ .iov_base = data.data.ptr, .iov_len = data.data.len }};
- try output.pwritevAll(&iovec, data.out_offset);
- },
- .copy_range => |range| {
- const copied_bytes = try source.copyRangeAll(range.in_offset, output, range.out_offset, range.len);
- if (copied_bytes < range.len) return error.TRUNCATED_ELF;
- },
- }
- }
+ try ElfFileHelper.write(allocator, out_file, in_file, cmdbuf.items);
}
fn sectionWithinSegment(section: Elf_Shdr, segment: Elf_Phdr) bool {
@@ -1262,15 +1137,162 @@ fn ElfContents(comptime is_64: bool) type {
};
}
-fn computeFileCrc(file: File) !u32 {
- var buf: [8000]u8 = undefined;
+const ElfFileHelper = struct {
+ const DebugLink = struct { name: []const u8, crc32: u32 };
+ const Filter = enum { all, program, debug, program_and_symbols, debug_and_symbols };
+
+ const SectionCategory = enum { common, exe, debug, symbols, none };
+ fn propagateCategory(cur: *SectionCategory, new: SectionCategory) u1 {
+ const cat: SectionCategory = switch (cur.*) {
+ .none => new,
+ .common => .common,
+ .debug => switch (new) {
+ .none, .debug => .debug,
+ else => new,
+ },
+ .exe => switch (new) {
+ .common => .common,
+ .none, .debug, .exe => .exe,
+ .symbols => .exe,
+ },
+ .symbols => switch (new) {
+ .none, .common, .debug, .exe => unreachable,
+ .symbols => .symbols,
+ },
+ };
- try file.seekTo(0);
- var hasher = std.hash.Crc32.init();
- while (true) {
- const bytes_read = try file.read(&buf);
- if (bytes_read == 0) break;
- hasher.update(buf[0..bytes_read]);
+ if (cur.* != cat) {
+ cur.* = cat;
+ return 1;
+ } else {
+ return 0;
+ }
}
- return hasher.final();
-}
+
+ const Action = enum { keep, strip, empty };
+ fn selectAction(category: SectionCategory, filter: Filter) Action {
+ if (category == .none) return .strip;
+ return switch (filter) {
+ .all => switch (category) {
+ .none => .strip,
+ else => .keep,
+ },
+ .program => switch (category) {
+ .common, .exe => .keep,
+ else => .strip,
+ },
+ .program_and_symbols => switch (category) {
+ .common, .exe, .symbols => .keep,
+ else => .strip,
+ },
+ .debug => switch (category) {
+ .exe, .symbols => .empty,
+ .none => .strip,
+ else => .keep,
+ },
+ .debug_and_symbols => switch (category) {
+ .exe => .empty,
+ .none => .strip,
+ else => .keep,
+ },
+ };
+ }
+
+ const WriteCmd = union(enum) {
+ copy_range: struct { in_offset: u64, len: u64, out_offset: u64 },
+ write_data: struct { data: []const u8, out_offset: u64 },
+ };
+ fn write(allocator: Allocator, out_file: File, in_file: File, cmds: []const WriteCmd) !void {
+ // consolidate holes between writes:
+ // by coping original padding data from in_file (by fusing contiguous ranges)
+ // by writing zeroes otherwise
+ const zeroes = [1]u8{0} ** 4096;
+ var consolidated = std.ArrayList(WriteCmd).init(allocator);
+ defer consolidated.deinit();
+ try consolidated.ensureUnusedCapacity(cmds.len * 2);
+ var offset: u64 = 0;
+ var fused_cmd: ?WriteCmd = null;
+ for (cmds) |cmd| {
+ switch (cmd) {
+ .write_data => |data| {
+ std.debug.assert(data.out_offset >= offset);
+ if (fused_cmd) |prev| {
+ consolidated.appendAssumeCapacity(prev);
+ fused_cmd = null;
+ }
+ if (data.out_offset > offset) {
+ consolidated.appendAssumeCapacity(.{ .write_data = .{ .data = zeroes[0..@intCast(usize, data.out_offset - offset)], .out_offset = offset } });
+ }
+ consolidated.appendAssumeCapacity(cmd);
+ offset = data.out_offset + data.data.len;
+ },
+ .copy_range => |range| {
+ std.debug.assert(range.out_offset >= offset);
+ if (fused_cmd) |prev| {
+ if (range.in_offset >= prev.copy_range.in_offset + prev.copy_range.len and (range.out_offset - prev.copy_range.out_offset == range.in_offset - prev.copy_range.in_offset)) {
+ fused_cmd = .{ .copy_range = .{
+ .in_offset = prev.copy_range.in_offset,
+ .out_offset = prev.copy_range.out_offset,
+ .len = (range.out_offset + range.len) - prev.copy_range.out_offset,
+ } };
+ } else {
+ consolidated.appendAssumeCapacity(prev);
+ if (range.out_offset > offset) {
+ consolidated.appendAssumeCapacity(.{ .write_data = .{ .data = zeroes[0..@intCast(usize, range.out_offset - offset)], .out_offset = offset } });
+ }
+ fused_cmd = cmd;
+ }
+ } else {
+ fused_cmd = cmd;
+ }
+ offset = range.out_offset + range.len;
+ },
+ }
+ }
+ if (fused_cmd) |cmd| {
+ consolidated.appendAssumeCapacity(cmd);
+ }
+
+ // write the output file
+ for (consolidated.items) |cmd| {
+ switch (cmd) {
+ .write_data => |data| {
+ var iovec = [_]std.os.iovec_const{.{ .iov_base = data.data.ptr, .iov_len = data.data.len }};
+ try out_file.pwritevAll(&iovec, data.out_offset);
+ },
+ .copy_range => |range| {
+ const copied_bytes = try in_file.copyRangeAll(range.in_offset, out_file, range.out_offset, range.len);
+ if (copied_bytes < range.len) return error.TRUNCATED_ELF;
+ },
+ }
+ }
+ }
+
+ fn createDebugLink(path: []const u8) DebugLink {
+ const file = std.fs.cwd().openFile(path, .{}) catch |err| {
+ fatal("zig objcopy: could not open `{s}`: {s}\n", .{ path, @errorName(err) });
+ };
+ defer file.close();
+
+ const crc = ElfFileHelper.computeFileCrc(file) catch |err| {
+ fatal("zig objcopy: could not read `{s}`: {s}\n", .{ path, @errorName(err) });
+ };
+ return .{
+ .name = std.fs.path.basename(path),
+ .crc32 = crc,
+ };
+ }
+
+ fn computeFileCrc(file: File) !u32 {
+ var buf: [8000]u8 = undefined;
+
+ try file.seekTo(0);
+ var hasher = std.hash.Crc32.init();
+ while (true) {
+ const bytes_read = try file.read(&buf);
+ if (bytes_read == 0) break;
+ hasher.update(buf[0..bytes_read]);
+ }
+ return hasher.final();
+ }
+};