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Merged
andrewrk merged 1 commit into from
Dec 4, 2021
Merged

Add single section dumping and output file padding to InstallRawStep #10267

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10 changes: 6 additions & 4 deletions lib/std/build.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -1018,8 +1018,10 @@ pub const Builder = struct {
}

/// Output format (BIN vs Intel HEX) determined by filename
pub fn installRaw(self: *Builder, artifact: *LibExeObjStep, dest_filename: []const u8, options: InstallRawStep.CreateOptions) void {
self.getInstallStep().dependOn(&self.addInstallRaw(artifact, dest_filename, options).step);
pub fn installRaw(self: *Builder, artifact: *LibExeObjStep, dest_filename: []const u8, options: InstallRawStep.CreateOptions) *InstallRawStep {
const raw = self.addInstallRaw(artifact, dest_filename, options);
self.getInstallStep().dependOn(&raw.step);
return raw;
}

///`dest_rel_path` is relative to install prefix path
Expand Down Expand Up @@ -1732,8 +1734,8 @@ pub const LibExeObjStep = struct {
self.builder.installArtifact(self);
}

pub fn installRaw(self: *LibExeObjStep, dest_filename: []const u8, options: InstallRawStep.CreateOptions) void {
self.builder.installRaw(self, dest_filename, options);
pub fn installRaw(self: *LibExeObjStep, dest_filename: []const u8, options: InstallRawStep.CreateOptions) *InstallRawStep {
return self.builder.installRaw(self, dest_filename, options);
}

/// Creates a `RunStep` with an executable built with `addExecutable`.
Expand Down
114 changes: 98 additions & 16 deletions lib/std/build/InstallRawStep.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ const std = @import("std");

const Allocator = std.mem.Allocator;
const ArenaAllocator = std.heap.ArenaAllocator;
const ArrayList = std.ArrayList;
const ArrayListUnmanaged = std.ArrayListUnmanaged;
const Builder = std.build.Builder;
const File = std.fs.File;
const InstallDir = std.build.InstallDir;
Expand All @@ -17,6 +17,7 @@ const BinaryElfSection = struct {
elfOffset: u64,
binaryOffset: u64,
fileSize: usize,
name: ?[]const u8,
segment: ?*BinaryElfSegment,
};

Expand All @@ -30,23 +31,55 @@ const BinaryElfSegment = struct {
};

const BinaryElfOutput = struct {
segments: ArrayList(*BinaryElfSegment),
sections: ArrayList(*BinaryElfSection),
segments: ArrayListUnmanaged(*BinaryElfSegment),
sections: ArrayListUnmanaged(*BinaryElfSection),
allocator: Allocator,
shstrtab: ?[]const u8,

const Self = @This();

pub fn deinit(self: *Self) void {
self.sections.deinit();
self.segments.deinit();
if (self.shstrtab) |shstrtab|
self.allocator.free(shstrtab);
self.sections.deinit(self.allocator);
self.segments.deinit(self.allocator);
}

pub fn parse(allocator: Allocator, elf_file: File) !Self {
var self: Self = .{
.segments = ArrayList(*BinaryElfSegment).init(allocator),
.sections = ArrayList(*BinaryElfSection).init(allocator),
.segments = .{},
.sections = .{},
.allocator = allocator,
.shstrtab = null,
};
errdefer self.sections.deinit(allocator);
errdefer self.segments.deinit(allocator);

const elf_hdr = try std.elf.Header.read(&elf_file);

self.shstrtab = blk: {
if (elf_hdr.shstrndx >= elf_hdr.shnum) break :blk null;

var section_headers = elf_hdr.section_header_iterator(&elf_file);

var section_counter: usize = 0;
while (section_counter < elf_hdr.shstrndx) : (section_counter += 1) {
_ = (try section_headers.next()).?;
}

const shstrtab_shdr = (try section_headers.next()).?;

const buffer = try allocator.alloc(u8, shstrtab_shdr.sh_size);
errdefer allocator.free(buffer);

const num_read = try elf_file.preadAll(buffer, shstrtab_shdr.sh_offset);
if (num_read != buffer.len) return error.EndOfStream;

break :blk buffer;
};

errdefer if (self.shstrtab) |shstrtab| allocator.free(shstrtab);

var section_headers = elf_hdr.section_header_iterator(&elf_file);
while (try section_headers.next()) |section| {
if (sectionValidForOutput(section)) {
Expand All @@ -57,7 +90,12 @@ const BinaryElfOutput = struct {
newSection.fileSize = @intCast(usize, section.sh_size);
newSection.segment = null;

try self.sections.append(newSection);
newSection.name = if (self.shstrtab) |shstrtab|
std.mem.span(@ptrCast([*:0]const u8, &shstrtab[section.sh_name]))
else
null;

try self.sections.append(allocator, newSection);
}
}

Expand Down Expand Up @@ -89,7 +127,7 @@ const BinaryElfOutput = struct {
}
}

try self.segments.append(newSegment);
try self.segments.append(allocator, newSegment);
}
}

Expand Down Expand Up @@ -150,8 +188,6 @@ const BinaryElfOutput = struct {
};

fn writeBinaryElfSection(elf_file: File, out_file: File, section: *BinaryElfSection) !void {
try out_file.seekTo(section.binaryOffset);

try out_file.writeFileAll(elf_file, .{
.in_offset = section.elfOffset,
.in_len = section.fileSize,
Expand Down Expand Up @@ -298,7 +334,20 @@ fn containsValidAddressRange(segments: []*BinaryElfSegment) bool {
return true;
}

fn emitRaw(allocator: Allocator, elf_path: []const u8, raw_path: []const u8, format: RawFormat) !void {
fn padFile(f: fs.File, size: ?usize) !void {
if (size) |pad_size| {
const current_size = try f.getEndPos();
if (current_size < pad_size) {
try f.seekTo(pad_size - 1);
try f.writer().writeByte(0);
}
if (current_size > pad_size) {
return error.FileTooLarge; // Maybe this shouldn't be an error?
}
}
}

fn emitRaw(allocator: Allocator, elf_path: []const u8, raw_path: []const u8, options: CreateOptions) !void {
var elf_file = try fs.cwd().openFile(elf_path, .{});
defer elf_file.close();

Expand All @@ -308,11 +357,38 @@ fn emitRaw(allocator: Allocator, elf_path: []const u8, raw_path: []const u8, for
var binary_elf_output = try BinaryElfOutput.parse(allocator, elf_file);
defer binary_elf_output.deinit();

switch (format) {
const effective_format = options.format orelse detectFormat(raw_path);

if (options.only_section_name) |target_name| {
switch (effective_format) {
// Hex format can only write segments/phdrs, sections not supported yet
.hex => return error.NotYetImplemented,
.bin => {
for (binary_elf_output.sections.items) |section| {
if (section.name) |curr_name| {
if (!std.mem.eql(u8, curr_name, target_name))
continue;
} else {
continue;
}

try writeBinaryElfSection(elf_file, out_file, section);
try padFile(out_file, options.pad_to_size);
return;
}
},
}

return error.SectionNotFound;
}

switch (effective_format) {
.bin => {
for (binary_elf_output.sections.items) |section| {
try out_file.seekTo(section.binaryOffset);
try writeBinaryElfSection(elf_file, out_file, section);
}
try padFile(out_file, options.pad_to_size);
},
.hex => {
if (binary_elf_output.segments.items.len == 0) return;
Expand All @@ -326,6 +402,10 @@ fn emitRaw(allocator: Allocator, elf_path: []const u8, raw_path: []const u8, for
try hex_writer.writeSegment(segment, elf_file);
}
}
if (options.pad_to_size) |_| {
// Padding to a size in hex files isn't applicable
return error.InvalidArgument;
}
try hex_writer.writeEOF();
},
}
Expand All @@ -345,7 +425,7 @@ builder: *Builder,
artifact: *LibExeObjStep,
dest_dir: InstallDir,
dest_filename: []const u8,
format: RawFormat,
options: CreateOptions,
output_file: std.build.GeneratedFile,

fn detectFormat(filename: []const u8) RawFormat {
Expand All @@ -358,6 +438,8 @@ fn detectFormat(filename: []const u8) RawFormat {
pub const CreateOptions = struct {
format: ?RawFormat = null,
dest_dir: ?InstallDir = null,
only_section_name: ?[]const u8 = null,
pad_to_size: ?usize = null,
};

pub fn create(builder: *Builder, artifact: *LibExeObjStep, dest_filename: []const u8, options: CreateOptions) *InstallRawStep {
Expand All @@ -373,7 +455,7 @@ pub fn create(builder: *Builder, artifact: *LibExeObjStep, dest_filename: []cons
.lib => unreachable,
},
.dest_filename = dest_filename,
.format = if (options.format) |f| f else detectFormat(dest_filename),
.options = options,
.output_file = std.build.GeneratedFile{ .step = &self.step },
};
self.step.dependOn(&artifact.step);
Expand All @@ -399,7 +481,7 @@ fn make(step: *Step) !void {
const full_dest_path = builder.getInstallPath(self.dest_dir, self.dest_filename);

fs.cwd().makePath(builder.getInstallPath(self.dest_dir, "")) catch unreachable;
try emitRaw(builder.allocator, full_src_path, full_dest_path, self.format);
try emitRaw(builder.allocator, full_src_path, full_dest_path, self.options);
self.output_file.path = full_dest_path;
}

Expand Down