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std.elf: buffer header iterator API (#24691)

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Closes #24666.
This commit is contained in:
Giuseppe Cesarano
2025-08-05 19:00:33 +02:00
committed by GitHub
parent 82961a8c9f
commit 3914eaf357
1 changed files with 92 additions and 38 deletions
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130
lib/std/elf.zig
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@@ -502,6 +502,13 @@ pub const Header = struct {
};
}
pub fn iterateProgramHeadersBuffer(h: Header, buf: []const u8) ProgramHeaderBufferIterator {
return .{
.elf_header = h,
.buf = buf,
};
}
pub fn iterateSectionHeaders(h: Header, file_reader: *std.fs.File.Reader) SectionHeaderIterator {
return .{
.elf_header = h,
@@ -509,6 +516,13 @@ pub const Header = struct {
};
}
pub fn iterateSectionHeadersBuffer(h: Header, buf: []const u8) SectionHeaderBufferIterator {
return .{
.elf_header = h,
.buf = buf,
};
}
pub const ReadError = std.Io.Reader.Error || error{
InvalidElfMagic,
InvalidElfVersion,
@@ -570,29 +584,48 @@ pub const ProgramHeaderIterator = struct {
if (it.index >= it.elf_header.phnum) return null;
defer it.index += 1;
if (it.elf_header.is_64) {
const offset = it.elf_header.phoff + @sizeOf(Elf64_Phdr) * it.index;
try it.file_reader.seekTo(offset);
const phdr = try it.file_reader.interface.takeStruct(Elf64_Phdr, it.elf_header.endian);
return phdr;
}
const offset = it.elf_header.phoff + @sizeOf(Elf32_Phdr) * it.index;
const offset = it.elf_header.phoff + if (it.elf_header.is_64) @sizeOf(Elf64_Phdr) else @sizeOf(Elf32_Phdr) * it.index;
try it.file_reader.seekTo(offset);
const phdr = try it.file_reader.interface.takeStruct(Elf32_Phdr, it.elf_header.endian);
return .{
.p_type = phdr.p_type,
.p_offset = phdr.p_offset,
.p_vaddr = phdr.p_vaddr,
.p_paddr = phdr.p_paddr,
.p_filesz = phdr.p_filesz,
.p_memsz = phdr.p_memsz,
.p_flags = phdr.p_flags,
.p_align = phdr.p_align,
};
return takePhdr(&it.file_reader.interface, it.elf_header);
}
};
pub const ProgramHeaderBufferIterator = struct {
elf_header: Header,
buf: []const u8,
index: usize = 0,
pub fn next(it: *ProgramHeaderBufferIterator) !?Elf64_Phdr {
if (it.index >= it.elf_header.phnum) return null;
defer it.index += 1;
const offset = it.elf_header.phoff + if (it.elf_header.is_64) @sizeOf(Elf64_Phdr) else @sizeOf(Elf32_Phdr) * it.index;
var reader = std.Io.Reader.fixed(it.buf[offset..]);
return takePhdr(&reader, it.elf_header);
}
};
fn takePhdr(reader: *std.io.Reader, elf_header: Header) !?Elf64_Phdr {
if (elf_header.is_64) {
const phdr = try reader.takeStruct(Elf64_Phdr, elf_header.endian);
return phdr;
}
const phdr = try reader.takeStruct(Elf32_Phdr, elf_header.endian);
return .{
.p_type = phdr.p_type,
.p_offset = phdr.p_offset,
.p_vaddr = phdr.p_vaddr,
.p_paddr = phdr.p_paddr,
.p_filesz = phdr.p_filesz,
.p_memsz = phdr.p_memsz,
.p_flags = phdr.p_flags,
.p_align = phdr.p_align,
};
}
pub const SectionHeaderIterator = struct {
elf_header: Header,
file_reader: *std.fs.File.Reader,
@@ -602,29 +635,50 @@ pub const SectionHeaderIterator = struct {
if (it.index >= it.elf_header.shnum) return null;
defer it.index += 1;
if (it.elf_header.is_64) {
try it.file_reader.seekTo(it.elf_header.shoff + @sizeOf(Elf64_Shdr) * it.index);
const shdr = try it.file_reader.interface.takeStruct(Elf64_Shdr, it.elf_header.endian);
return shdr;
}
const offset = it.elf_header.shoff + if (it.elf_header.is_64) @sizeOf(Elf64_Shdr) else @sizeOf(Elf32_Shdr) * it.index;
try it.file_reader.seekTo(offset);
try it.file_reader.seekTo(it.elf_header.shoff + @sizeOf(Elf32_Shdr) * it.index);
const shdr = try it.file_reader.interface.takeStruct(Elf32_Shdr, it.elf_header.endian);
return .{
.sh_name = shdr.sh_name,
.sh_type = shdr.sh_type,
.sh_flags = shdr.sh_flags,
.sh_addr = shdr.sh_addr,
.sh_offset = shdr.sh_offset,
.sh_size = shdr.sh_size,
.sh_link = shdr.sh_link,
.sh_info = shdr.sh_info,
.sh_addralign = shdr.sh_addralign,
.sh_entsize = shdr.sh_entsize,
};
return takeShdr(&it.file_reader.interface, it.elf_header);
}
};
pub const SectionHeaderBufferIterator = struct {
elf_header: Header,
buf: []const u8,
index: usize = 0,
pub fn next(it: *SectionHeaderBufferIterator) !?Elf64_Shdr {
if (it.index >= it.elf_header.shnum) return null;
defer it.index += 1;
const offset = it.elf_header.shoff + if (it.elf_header.is_64) @sizeOf(Elf64_Shdr) else @sizeOf(Elf32_Shdr) * it.index;
var reader = std.Io.Reader.fixed(it.buf[offset..]);
return takeShdr(&reader, it.elf_header);
}
};
fn takeShdr(reader: *std.Io.Reader, elf_header: Header) !?Elf64_Shdr {
if (elf_header.is_64) {
const shdr = try reader.takeStruct(Elf64_Shdr, elf_header.endian);
return shdr;
}
const shdr = try reader.takeStruct(Elf32_Shdr, elf_header.endian);
return .{
.sh_name = shdr.sh_name,
.sh_type = shdr.sh_type,
.sh_flags = shdr.sh_flags,
.sh_addr = shdr.sh_addr,
.sh_offset = shdr.sh_offset,
.sh_size = shdr.sh_size,
.sh_link = shdr.sh_link,
.sh_info = shdr.sh_info,
.sh_addralign = shdr.sh_addralign,
.sh_entsize = shdr.sh_entsize,
};
}
pub const ELFCLASSNONE = 0;
pub const ELFCLASS32 = 1;
pub const ELFCLASS64 = 2;