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Commit 76483877 authored by Austin Clements's avatar Austin Clements
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debug/elf: transparently decompress compressed sections 

This adds support for compressed ELF sections. This compression is
treated as a framing issue and hence the package APIs all
transparently decompress compressed sections. This requires some
subtlety for (*Section).Open, which returns an io.ReadSeeker: since
the decompressed data comes from an io.Reader, this commit introduces
a Reader-to-ReadSeeker adapter that is efficient for common uses of
Seek and does what it can otherwise.

Fixes #11773.

Change-Id: Ic0cb7255a85cadf4c1d15fb563d5a2e89dbd3c36
Reviewed-on: https://go-review.googlesource.com/17341Reviewed-by: 's avatarRuss Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
parent e1544d3b
Hide whitespace changes
Inline Side-by-side
Showing with 424 additions and 77 deletions
src/debug/elf/elf.go
View file @ 76483877
......@@ -411,6 +411,7 @@ const (
SHF_OS_NONCONFORMING SectionFlag = 0x100 /* OS-specific processing required. */
SHF_GROUP SectionFlag = 0x200 /* Member of section group. */
SHF_TLS SectionFlag = 0x400 /* Section contains TLS data. */
SHF_COMPRESSED SectionFlag = 0x800 /* Section is compressed. */
SHF_MASKOS SectionFlag = 0x0ff00000 /* OS-specific semantics. */
SHF_MASKPROC SectionFlag = 0xf0000000 /* Processor-specific semantics. */
)
......@@ -426,11 +427,34 @@ var shfStrings = []intName{
{0x100, "SHF_OS_NONCONFORMING"},
{0x200, "SHF_GROUP"},
{0x400, "SHF_TLS"},
{0x800, "SHF_COMPRESSED"},
}
func (i SectionFlag) String() string { return flagName(uint32(i), shfStrings, false) }
func (i SectionFlag) GoString() string { return flagName(uint32(i), shfStrings, true) }
// Section compression type.
type CompressionType int
const (
COMPRESS_ZLIB CompressionType = 1 /* ZLIB compression. */
COMPRESS_LOOS CompressionType = 0x60000000 /* First OS-specific. */
COMPRESS_HIOS CompressionType = 0x6fffffff /* Last OS-specific. */
COMPRESS_LOPROC CompressionType = 0x70000000 /* First processor-specific type. */
COMPRESS_HIPROC CompressionType = 0x7fffffff /* Last processor-specific type. */
)
var compressionStrings = []intName{
{0, "COMPRESS_ZLIB"},
{0x60000000, "COMPRESS_LOOS"},
{0x6fffffff, "COMPRESS_HIOS"},
{0x70000000, "COMPRESS_LOPROC"},
{0x7fffffff, "COMPRESS_HIPROC"},
}
func (i CompressionType) String() string { return stringName(uint32(i), compressionStrings, false) }
func (i CompressionType) GoString() string { return stringName(uint32(i), compressionStrings, true) }
// Prog.Type
type ProgType int
......@@ -1878,6 +1902,13 @@ type Dyn32 struct {
Val uint32 /* Integer/Address value. */
}
// ELF32 Compression header.
type Chdr32 struct {
Type uint32
Size uint32
Addralign uint32
}
/*
* Relocation entries.
*/
......@@ -1972,6 +2003,14 @@ type Dyn64 struct {
Val uint64 /* Integer/address value */
}
// ELF64 Compression header.
type Chdr64 struct {
Type uint32
Reserved uint32
Size uint64
Addralign uint64
}
/*
* Relocation entries.
*/
......
src/debug/elf/file.go
View file @ 76483877
......@@ -58,6 +58,12 @@ type SectionHeader struct {
Info uint32
Addralign uint64
Entsize uint64
// FileSize is the size of this section in the file in bytes.
// If a section is compressed, FileSize is the size of the
// compressed data, while Size (above) is the size of the
// uncompressed data.
FileSize uint64
}
// A Section represents a single section in an ELF file.
......@@ -70,17 +76,23 @@ type Section struct {
// If a client wants Read and Seek it must use
// Open() to avoid fighting over the seek offset
// with other clients.
//
// ReaderAt may be nil if the section is not easily available
// in a random-access form. For example, a compressed section
// may have a nil ReaderAt.
io.ReaderAt
sr *io.SectionReader
compressionType CompressionType
compressionOffset int64
}
// Data reads and returns the contents of the ELF section.
// Even if the section is stored compressed in the ELF file,
// Data returns uncompressed data.
func (s *Section) Data() ([]byte, error) {
dat := make([]byte, s.sr.Size())
n, err := s.sr.ReadAt(dat, 0)
if n == len(dat) {
err = nil
}
dat := make([]byte, s.Size)
n, err := io.ReadFull(s.Open(), dat)
return dat[0:n], err
}
......@@ -94,7 +106,24 @@ func (f *File) stringTable(link uint32) ([]byte, error) {
}
// Open returns a new ReadSeeker reading the ELF section.
func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
// Even if the section is stored compressed in the ELF file,
// the ReadSeeker reads uncompressed data.
func (s *Section) Open() io.ReadSeeker {
if s.Flags&SHF_COMPRESSED == 0 {
return io.NewSectionReader(s.sr, 0, 1<<63-1)
}
if s.compressionType == COMPRESS_ZLIB {
return &readSeekerFromReader{
reset: func() (io.Reader, error) {
fr := io.NewSectionReader(s.sr, s.compressionOffset, int64(s.FileSize)-s.compressionOffset)
return zlib.NewReader(fr)
},
size: int64(s.Size),
}
}
err := &FormatError{int64(s.Offset), "unknown compression type", s.compressionType}
return errorReader{err}
}
// A ProgHeader represents a single ELF program header.
type ProgHeader struct {
......@@ -344,7 +373,7 @@ func NewFile(r io.ReaderAt) (*File, error) {
Flags: SectionFlag(sh.Flags),
Addr: uint64(sh.Addr),
Offset: uint64(sh.Off),
Size: uint64(sh.Size),
FileSize: uint64(sh.Size),
Link: uint32(sh.Link),
Info: uint32(sh.Info),
Addralign: uint64(sh.Addralign),
......@@ -360,7 +389,7 @@ func NewFile(r io.ReaderAt) (*File, error) {
Type: SectionType(sh.Type),
Flags: SectionFlag(sh.Flags),
Offset: uint64(sh.Off),
Size: uint64(sh.Size),
FileSize: uint64(sh.Size),
Addr: uint64(sh.Addr),
Link: uint32(sh.Link),
Info: uint32(sh.Info),
......@@ -368,8 +397,35 @@ func NewFile(r io.ReaderAt) (*File, error) {
Entsize: uint64(sh.Entsize),
}
}
s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Size))
s.ReaderAt = s.sr
s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.FileSize))
if s.Flags&SHF_COMPRESSED == 0 {
s.ReaderAt = s.sr
s.Size = s.FileSize
} else {
// Read the compression header.
switch f.Class {
case ELFCLASS32:
ch := new(Chdr32)
if err := binary.Read(s.sr, f.ByteOrder, ch); err != nil {
return nil, err
}
s.compressionType = CompressionType(ch.Type)
s.Size = uint64(ch.Size)
s.Addralign = uint64(ch.Addralign)
s.compressionOffset = int64(binary.Size(ch))
case ELFCLASS64:
ch := new(Chdr64)
if err := binary.Read(s.sr, f.ByteOrder, ch); err != nil {
return nil, err
}
s.compressionType = CompressionType(ch.Type)
s.Size = ch.Size
s.Addralign = ch.Addralign
s.compressionOffset = int64(binary.Size(ch))
}
}
f.Sections[i] = s
}
......
src/debug/elf/file_test.go
View file @ 76483877
......@@ -10,6 +10,7 @@ import (
"debug/dwarf"
"encoding/binary"
"io"
"math/rand"
"net"
"os"
"path"
......@@ -31,36 +32,36 @@ var fileTests = []fileTest{
"testdata/gcc-386-freebsd-exec",
FileHeader{ELFCLASS32, ELFDATA2LSB, EV_CURRENT, ELFOSABI_FREEBSD, 0, binary.LittleEndian, ET_EXEC, EM_386, 0x80483cc},
[]SectionHeader{
{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
{".interp", SHT_PROGBITS, SHF_ALLOC, 0x80480d4, 0xd4, 0x15, 0x0, 0x0, 0x1, 0x0},
{".hash", SHT_HASH, SHF_ALLOC, 0x80480ec, 0xec, 0x90, 0x3, 0x0, 0x4, 0x4},
{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x804817c, 0x17c, 0x110, 0x4, 0x1, 0x4, 0x10},
{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x804828c, 0x28c, 0xbb, 0x0, 0x0, 0x1, 0x0},
{".rel.plt", SHT_REL, SHF_ALLOC, 0x8048348, 0x348, 0x20, 0x3, 0x7, 0x4, 0x8},
{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x8048368, 0x368, 0x11, 0x0, 0x0, 0x4, 0x0},
{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804837c, 0x37c, 0x50, 0x0, 0x0, 0x4, 0x4},
{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x80483cc, 0x3cc, 0x180, 0x0, 0x0, 0x4, 0x0},
{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804854c, 0x54c, 0xc, 0x0, 0x0, 0x4, 0x0},
{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x8048558, 0x558, 0xa3, 0x0, 0x0, 0x1, 0x0},
{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80495fc, 0x5fc, 0xc, 0x0, 0x0, 0x4, 0x0},
{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x8049608, 0x608, 0x4, 0x0, 0x0, 0x4, 0x0},
{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x804960c, 0x60c, 0x98, 0x4, 0x0, 0x4, 0x8},
{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496a4, 0x6a4, 0x8, 0x0, 0x0, 0x4, 0x0},
{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496ac, 0x6ac, 0x8, 0x0, 0x0, 0x4, 0x0},
{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b4, 0x6b4, 0x4, 0x0, 0x0, 0x4, 0x0},
{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b8, 0x6b8, 0x1c, 0x0, 0x0, 0x4, 0x4},
{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x80496d4, 0x6d4, 0x20, 0x0, 0x0, 0x4, 0x0},
{".comment", SHT_PROGBITS, 0x0, 0x0, 0x6d4, 0x12d, 0x0, 0x0, 0x1, 0x0},
{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x801, 0x20, 0x0, 0x0, 0x1, 0x0},
{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0x821, 0x1b, 0x0, 0x0, 0x1, 0x0},
{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0x83c, 0x11d, 0x0, 0x0, 0x1, 0x0},
{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0x959, 0x41, 0x0, 0x0, 0x1, 0x0},
{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x99a, 0x35, 0x0, 0x0, 0x1, 0x0},
{".debug_frame", SHT_PROGBITS, 0x0, 0x0, 0x9d0, 0x30, 0x0, 0x0, 0x4, 0x0},
{".debug_str", SHT_PROGBITS, 0x0, 0x0, 0xa00, 0xd, 0x0, 0x0, 0x1, 0x0},
{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xa0d, 0xf8, 0x0, 0x0, 0x1, 0x0},
{".symtab", SHT_SYMTAB, 0x0, 0x0, 0xfb8, 0x4b0, 0x1d, 0x38, 0x4, 0x10},
{".strtab", SHT_STRTAB, 0x0, 0x0, 0x1468, 0x206, 0x0, 0x0, 0x1, 0x0},
{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
{".interp", SHT_PROGBITS, SHF_ALLOC, 0x80480d4, 0xd4, 0x15, 0x0, 0x0, 0x1, 0x0, 0x15},
{".hash", SHT_HASH, SHF_ALLOC, 0x80480ec, 0xec, 0x90, 0x3, 0x0, 0x4, 0x4, 0x90},
{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x804817c, 0x17c, 0x110, 0x4, 0x1, 0x4, 0x10, 0x110},
{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x804828c, 0x28c, 0xbb, 0x0, 0x0, 0x1, 0x0, 0xbb},
{".rel.plt", SHT_REL, SHF_ALLOC, 0x8048348, 0x348, 0x20, 0x3, 0x7, 0x4, 0x8, 0x20},
{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x8048368, 0x368, 0x11, 0x0, 0x0, 0x4, 0x0, 0x11},
{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804837c, 0x37c, 0x50, 0x0, 0x0, 0x4, 0x4, 0x50},
{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x80483cc, 0x3cc, 0x180, 0x0, 0x0, 0x4, 0x0, 0x180},
{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804854c, 0x54c, 0xc, 0x0, 0x0, 0x4, 0x0, 0xc},
{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x8048558, 0x558, 0xa3, 0x0, 0x0, 0x1, 0x0, 0xa3},
{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80495fc, 0x5fc, 0xc, 0x0, 0x0, 0x4, 0x0, 0xc},
{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x8049608, 0x608, 0x4, 0x0, 0x0, 0x4, 0x0, 0x4},
{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x804960c, 0x60c, 0x98, 0x4, 0x0, 0x4, 0x8, 0x98},
{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496a4, 0x6a4, 0x8, 0x0, 0x0, 0x4, 0x0, 0x8},
{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496ac, 0x6ac, 0x8, 0x0, 0x0, 0x4, 0x0, 0x8},
{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b4, 0x6b4, 0x4, 0x0, 0x0, 0x4, 0x0, 0x4},
{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b8, 0x6b8, 0x1c, 0x0, 0x0, 0x4, 0x4, 0x1c},
{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x80496d4, 0x6d4, 0x20, 0x0, 0x0, 0x4, 0x0, 0x20},
{".comment", SHT_PROGBITS, 0x0, 0x0, 0x6d4, 0x12d, 0x0, 0x0, 0x1, 0x0, 0x12d},
{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x801, 0x20, 0x0, 0x0, 0x1, 0x0, 0x20},
{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0x821, 0x1b, 0x0, 0x0, 0x1, 0x0, 0x1b},
{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0x83c, 0x11d, 0x0, 0x0, 0x1, 0x0, 0x11d},
{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0x959, 0x41, 0x0, 0x0, 0x1, 0x0, 0x41},
{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x99a, 0x35, 0x0, 0x0, 0x1, 0x0, 0x35},
{".debug_frame", SHT_PROGBITS, 0x0, 0x0, 0x9d0, 0x30, 0x0, 0x0, 0x4, 0x0, 0x30},
{".debug_str", SHT_PROGBITS, 0x0, 0x0, 0xa00, 0xd, 0x0, 0x0, 0x1, 0x0, 0xd},
{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xa0d, 0xf8, 0x0, 0x0, 0x1, 0x0, 0xf8},
{".symtab", SHT_SYMTAB, 0x0, 0x0, 0xfb8, 0x4b0, 0x1d, 0x38, 0x4, 0x10, 0x4b0},
{".strtab", SHT_STRTAB, 0x0, 0x0, 0x1468, 0x206, 0x0, 0x0, 0x1, 0x0, 0x206},
},
[]ProgHeader{
{PT_PHDR, PF_R + PF_X, 0x34, 0x8048034, 0x8048034, 0xa0, 0xa0, 0x4},
......@@ -75,43 +76,43 @@ var fileTests = []fileTest{
"testdata/gcc-amd64-linux-exec",
FileHeader{ELFCLASS64, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0, binary.LittleEndian, ET_EXEC, EM_X86_64, 0x4003e0},
[]SectionHeader{
{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
{".interp", SHT_PROGBITS, SHF_ALLOC, 0x400200, 0x200, 0x1c, 0x0, 0x0, 0x1, 0x0},
{".note.ABI-tag", SHT_NOTE, SHF_ALLOC, 0x40021c, 0x21c, 0x20, 0x0, 0x0, 0x4, 0x0},
{".hash", SHT_HASH, SHF_ALLOC, 0x400240, 0x240, 0x24, 0x5, 0x0, 0x8, 0x4},
{".gnu.hash", SHT_LOOS + 268435446, SHF_ALLOC, 0x400268, 0x268, 0x1c, 0x5, 0x0, 0x8, 0x0},
{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x400288, 0x288, 0x60, 0x6, 0x1, 0x8, 0x18},
{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x4002e8, 0x2e8, 0x3d, 0x0, 0x0, 0x1, 0x0},
{".gnu.version", SHT_HIOS, SHF_ALLOC, 0x400326, 0x326, 0x8, 0x5, 0x0, 0x2, 0x2},
{".gnu.version_r", SHT_LOOS + 268435454, SHF_ALLOC, 0x400330, 0x330, 0x20, 0x6, 0x1, 0x8, 0x0},
{".rela.dyn", SHT_RELA, SHF_ALLOC, 0x400350, 0x350, 0x18, 0x5, 0x0, 0x8, 0x18},
{".rela.plt", SHT_RELA, SHF_ALLOC, 0x400368, 0x368, 0x30, 0x5, 0xc, 0x8, 0x18},
{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400398, 0x398, 0x18, 0x0, 0x0, 0x4, 0x0},
{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003b0, 0x3b0, 0x30, 0x0, 0x0, 0x4, 0x10},
{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003e0, 0x3e0, 0x1b4, 0x0, 0x0, 0x10, 0x0},
{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400594, 0x594, 0xe, 0x0, 0x0, 0x4, 0x0},
{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x4005a4, 0x5a4, 0x11, 0x0, 0x0, 0x4, 0x0},
{".eh_frame_hdr", SHT_PROGBITS, SHF_ALLOC, 0x4005b8, 0x5b8, 0x24, 0x0, 0x0, 0x4, 0x0},
{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x4005e0, 0x5e0, 0xa4, 0x0, 0x0, 0x8, 0x0},
{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600688, 0x688, 0x10, 0x0, 0x0, 0x8, 0x0},
{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600698, 0x698, 0x10, 0x0, 0x0, 0x8, 0x0},
{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x6006a8, 0x6a8, 0x8, 0x0, 0x0, 0x8, 0x0},
{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x6006b0, 0x6b0, 0x1a0, 0x6, 0x0, 0x8, 0x10},
{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600850, 0x850, 0x8, 0x0, 0x0, 0x8, 0x8},
{".got.plt", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600858, 0x858, 0x28, 0x0, 0x0, 0x8, 0x8},
{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600880, 0x880, 0x18, 0x0, 0x0, 0x8, 0x0},
{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x600898, 0x898, 0x8, 0x0, 0x0, 0x4, 0x0},
{".comment", SHT_PROGBITS, 0x0, 0x0, 0x898, 0x126, 0x0, 0x0, 0x1, 0x0},
{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x9c0, 0x90, 0x0, 0x0, 0x10, 0x0},
{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0xa50, 0x25, 0x0, 0x0, 0x1, 0x0},
{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0xa75, 0x1a7, 0x0, 0x0, 0x1, 0x0},
{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xc1c, 0x6f, 0x0, 0x0, 0x1, 0x0},
{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0xc8b, 0x13f, 0x0, 0x0, 0x1, 0x0},
{".debug_str", SHT_PROGBITS, SHF_MERGE + SHF_STRINGS, 0x0, 0xdca, 0xb1, 0x0, 0x0, 0x1, 0x1},
{".debug_ranges", SHT_PROGBITS, 0x0, 0x0, 0xe80, 0x90, 0x0, 0x0, 0x10, 0x0},
{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xf10, 0x149, 0x0, 0x0, 0x1, 0x0},
{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x19a0, 0x6f0, 0x24, 0x39, 0x8, 0x18},
{".strtab", SHT_STRTAB, 0x0, 0x0, 0x2090, 0x1fc, 0x0, 0x0, 0x1, 0x0},
{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
{".interp", SHT_PROGBITS, SHF_ALLOC, 0x400200, 0x200, 0x1c, 0x0, 0x0, 0x1, 0x0, 0x1c},
{".note.ABI-tag", SHT_NOTE, SHF_ALLOC, 0x40021c, 0x21c, 0x20, 0x0, 0x0, 0x4, 0x0, 0x20},
{".hash", SHT_HASH, SHF_ALLOC, 0x400240, 0x240, 0x24, 0x5, 0x0, 0x8, 0x4, 0x24},
{".gnu.hash", SHT_LOOS + 268435446, SHF_ALLOC, 0x400268, 0x268, 0x1c, 0x5, 0x0, 0x8, 0x0, 0x1c},
{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x400288, 0x288, 0x60, 0x6, 0x1, 0x8, 0x18, 0x60},
{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x4002e8, 0x2e8, 0x3d, 0x0, 0x0, 0x1, 0x0, 0x3d},
{".gnu.version", SHT_HIOS, SHF_ALLOC, 0x400326, 0x326, 0x8, 0x5, 0x0, 0x2, 0x2, 0x8},
{".gnu.version_r", SHT_LOOS + 268435454, SHF_ALLOC, 0x400330, 0x330, 0x20, 0x6, 0x1, 0x8, 0x0, 0x20},
{".rela.dyn", SHT_RELA, SHF_ALLOC, 0x400350, 0x350, 0x18, 0x5, 0x0, 0x8, 0x18, 0x18},
{".rela.plt", SHT_RELA, SHF_ALLOC, 0x400368, 0x368, 0x30, 0x5, 0xc, 0x8, 0x18, 0x30},
{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400398, 0x398, 0x18, 0x0, 0x0, 0x4, 0x0, 0x18},
{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003b0, 0x3b0, 0x30, 0x0, 0x0, 0x4, 0x10, 0x30},
{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003e0, 0x3e0, 0x1b4, 0x0, 0x0, 0x10, 0x0, 0x1b4},
{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400594, 0x594, 0xe, 0x0, 0x0, 0x4, 0x0, 0xe},
{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x4005a4, 0x5a4, 0x11, 0x0, 0x0, 0x4, 0x0, 0x11},
{".eh_frame_hdr", SHT_PROGBITS, SHF_ALLOC, 0x4005b8, 0x5b8, 0x24, 0x0, 0x0, 0x4, 0x0, 0x24},
{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x4005e0, 0x5e0, 0xa4, 0x0, 0x0, 0x8, 0x0, 0xa4},
{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600688, 0x688, 0x10, 0x0, 0x0, 0x8, 0x0, 0x10},
{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600698, 0x698, 0x10, 0x0, 0x0, 0x8, 0x0, 0x10},
{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x6006a8, 0x6a8, 0x8, 0x0, 0x0, 0x8, 0x0, 0x8},
{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x6006b0, 0x6b0, 0x1a0, 0x6, 0x0, 0x8, 0x10, 0x1a0},
{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600850, 0x850, 0x8, 0x0, 0x0, 0x8, 0x8, 0x8},
{".got.plt", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600858, 0x858, 0x28, 0x0, 0x0, 0x8, 0x8, 0x28},
{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600880, 0x880, 0x18, 0x0, 0x0, 0x8, 0x0, 0x18},
{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x600898, 0x898, 0x8, 0x0, 0x0, 0x4, 0x0, 0x8},
{".comment", SHT_PROGBITS, 0x0, 0x0, 0x898, 0x126, 0x0, 0x0, 0x1, 0x0, 0x126},
{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x9c0, 0x90, 0x0, 0x0, 0x10, 0x0, 0x90},
{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0xa50, 0x25, 0x0, 0x0, 0x1, 0x0, 0x25},
{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0xa75, 0x1a7, 0x0, 0x0, 0x1, 0x0, 0x1a7},
{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xc1c, 0x6f, 0x0, 0x0, 0x1, 0x0, 0x6f},
{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0xc8b, 0x13f, 0x0, 0x0, 0x1, 0x0, 0x13f},
{".debug_str", SHT_PROGBITS, SHF_MERGE + SHF_STRINGS, 0x0, 0xdca, 0xb1, 0x0, 0x0, 0x1, 0x1, 0xb1},
{".debug_ranges", SHT_PROGBITS, 0x0, 0x0, 0xe80, 0x90, 0x0, 0x0, 0x10, 0x0, 0x90},
{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xf10, 0x149, 0x0, 0x0, 0x1, 0x0, 0x149},
{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x19a0, 0x6f0, 0x24, 0x39, 0x8, 0x18, 0x6f0},
{".strtab", SHT_STRTAB, 0x0, 0x0, 0x2090, 0x1fc, 0x0, 0x0, 0x1, 0x0, 0x1fc},
},
[]ProgHeader{
{PT_PHDR, PF_R + PF_X, 0x40, 0x400040, 0x400040, 0x1c0, 0x1c0, 0x8},
......@@ -150,6 +151,64 @@ var fileTests = []fileTest{
},
nil,
},
{
"testdata/compressed-32.obj",
FileHeader{ELFCLASS32, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0x0, binary.LittleEndian, ET_REL, EM_386, 0x0},
[]SectionHeader{
{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
{".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, 0x0, 0x34, 0x17, 0x0, 0x0, 0x1, 0x0, 0x17},
{".rel.text", SHT_REL, SHF_INFO_LINK, 0x0, 0x3dc, 0x10, 0x13, 0x1, 0x4, 0x8, 0x10},
{".data", SHT_PROGBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x4b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
{".bss", SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x4b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x4b, 0xd, 0x0, 0x0, 0x1, 0x0, 0xd},
{".debug_info", SHT_PROGBITS, SHF_COMPRESSED, 0x0, 0x58, 0xb4, 0x0, 0x0, 0x1, 0x0, 0x84},
{".rel.debug_info", SHT_REL, SHF_INFO_LINK, 0x0, 0x3ec, 0xa0, 0x13, 0x6, 0x4, 0x8, 0xa0},
{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xdc, 0x5a, 0x0, 0x0, 0x1, 0x0, 0x5a},
{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x136, 0x20, 0x0, 0x0, 0x1, 0x0, 0x20},
{".rel.debug_aranges", SHT_REL, SHF_INFO_LINK, 0x0, 0x48c, 0x10, 0x13, 0x9, 0x4, 0x8, 0x10},
{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x156, 0x5c, 0x0, 0x0, 0x1, 0x0, 0x5c},
{".rel.debug_line", SHT_REL, SHF_INFO_LINK, 0x0, 0x49c, 0x8, 0x13, 0xb, 0x4, 0x8, 0x8},
{".debug_str", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS | SHF_COMPRESSED, 0x0, 0x1b2, 0x10f, 0x0, 0x0, 0x1, 0x1, 0xb3},
{".comment", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS, 0x0, 0x265, 0x2a, 0x0, 0x0, 0x1, 0x1, 0x2a},
{".note.GNU-stack", SHT_PROGBITS, 0x0, 0x0, 0x28f, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x290, 0x38, 0x0, 0x0, 0x4, 0x0, 0x38},
{".rel.eh_frame", SHT_REL, SHF_INFO_LINK, 0x0, 0x4a4, 0x8, 0x13, 0x10, 0x4, 0x8, 0x8},
{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0x4ac, 0xab, 0x0, 0x0, 0x1, 0x0, 0xab},
{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x2c8, 0x100, 0x14, 0xe, 0x4, 0x10, 0x100},
{".strtab", SHT_STRTAB, 0x0, 0x0, 0x3c8, 0x13, 0x0, 0x0, 0x1, 0x0, 0x13},
},
[]ProgHeader{},
nil,
},
{
"testdata/compressed-64.obj",
FileHeader{ELFCLASS64, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0x0, binary.LittleEndian, ET_REL, EM_X86_64, 0x0},
[]SectionHeader{
{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
{".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, 0x0, 0x40, 0x1b, 0x0, 0x0, 0x1, 0x0, 0x1b},
{".rela.text", SHT_RELA, SHF_INFO_LINK, 0x0, 0x488, 0x30, 0x13, 0x1, 0x8, 0x18, 0x30},
{".data", SHT_PROGBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x5b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
{".bss", SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x5b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x5b, 0xd, 0x0, 0x0, 0x1, 0x0, 0xd},
{".debug_info", SHT_PROGBITS, SHF_COMPRESSED, 0x0, 0x68, 0xba, 0x0, 0x0, 0x1, 0x0, 0x72},
{".rela.debug_info", SHT_RELA, SHF_INFO_LINK, 0x0, 0x4b8, 0x1c8, 0x13, 0x6, 0x8, 0x18, 0x1c8},
{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xda, 0x5c, 0x0, 0x0, 0x1, 0x0, 0x5c},
{".debug_aranges", SHT_PROGBITS, SHF_COMPRESSED, 0x0, 0x136, 0x30, 0x0, 0x0, 0x1, 0x0, 0x2f},
{".rela.debug_aranges", SHT_RELA, SHF_INFO_LINK, 0x0, 0x680, 0x30, 0x13, 0x9, 0x8, 0x18, 0x30},
{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x165, 0x60, 0x0, 0x0, 0x1, 0x0, 0x60},
{".rela.debug_line", SHT_RELA, SHF_INFO_LINK, 0x0, 0x6b0, 0x18, 0x13, 0xb, 0x8, 0x18, 0x18},
{".debug_str", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS | SHF_COMPRESSED, 0x0, 0x1c5, 0x104, 0x0, 0x0, 0x1, 0x1, 0xc3},
{".comment", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS, 0x0, 0x288, 0x2a, 0x0, 0x0, 0x1, 0x1, 0x2a},
{".note.GNU-stack", SHT_PROGBITS, 0x0, 0x0, 0x2b2, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x2b8, 0x38, 0x0, 0x0, 0x8, 0x0, 0x38},
{".rela.eh_frame", SHT_RELA, SHF_INFO_LINK, 0x0, 0x6c8, 0x18, 0x13, 0x10, 0x8, 0x18, 0x18},
{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0x6e0, 0xb0, 0x0, 0x0, 0x1, 0x0, 0xb0},
{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x2f0, 0x180, 0x14, 0xe, 0x8, 0x18, 0x180},
{".strtab", SHT_STRTAB, 0x0, 0x0, 0x470, 0x13, 0x0, 0x0, 0x1, 0x0, 0x13},
},
[]ProgHeader{},
nil,
},
}
func TestOpen(t *testing.T) {
......@@ -542,6 +601,91 @@ func TestCompressedDWARF(t *testing.T) {
}
}
func TestCompressedSection(t *testing.T) {
// Test files built with gcc -g -S hello.c and assembled with
// --compress-debug-sections=zlib-gabi.
f, err := Open("testdata/compressed-64.obj")
if err != nil {
t.Fatal(err)
}
sec := f.Section(".debug_info")
wantData := []byte{
182, 0, 0, 0, 4, 0, 0, 0, 0, 0, 8, 1, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 27, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 8, 7,
0, 0, 0, 0, 2, 1, 8, 0, 0, 0, 0, 2, 2, 7, 0, 0,
0, 0, 2, 4, 7, 0, 0, 0, 0, 2, 1, 6, 0, 0, 0, 0,
2, 2, 5, 0, 0, 0, 0, 3, 4, 5, 105, 110, 116, 0, 2, 8,
5, 0, 0, 0, 0, 2, 8, 7, 0, 0, 0, 0, 4, 8, 114, 0,
0, 0, 2, 1, 6, 0, 0, 0, 0, 5, 0, 0, 0, 0, 1, 4,
0, 0, 0, 0, 0, 0, 0, 0, 27, 0, 0, 0, 0, 0, 0, 0,
1, 156, 179, 0, 0, 0, 6, 0, 0, 0, 0, 1, 4, 87, 0, 0,
0, 2, 145, 108, 6, 0, 0, 0, 0, 1, 4, 179, 0, 0, 0, 2,
145, 96, 0, 4, 8, 108, 0, 0, 0, 0,
}
// Test Data method.
b, err := sec.Data()
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(wantData, b) {
t.Fatalf("want data %x, got %x", wantData, b)
}
// Test Open method and seeking.
buf, have, count := make([]byte, len(b)), make([]bool, len(b)), 0
sf := sec.Open()
if got, err := sf.Seek(0, 2); got != int64(len(b)) || err != nil {
t.Fatalf("want seek end %d, got %d error %v", len(b), got, err)
}
if n, err := sf.Read(buf); n != 0 || err != io.EOF {
t.Fatalf("want EOF with 0 bytes, got %v with %d bytes", err, n)
}
pos := int64(len(buf))
for count < len(buf) {
// Construct random seek arguments.
whence := rand.Intn(3)
target := rand.Int63n(int64(len(buf)))
var offset int64
switch whence {
case 0:
offset = target
case 1:
offset = target - pos
case 2:
offset = target - int64(len(buf))
}
pos, err = sf.Seek(offset, whence)
if err != nil {
t.Fatal(err)
}
if pos != target {
t.Fatalf("want position %d, got %d", target, pos)
}
// Read data from the new position.
end := pos + 16
if end > int64(len(buf)) {
end = int64(len(buf))
}
n, err := sf.Read(buf[pos:end])
if err != nil {
t.Fatal(err)
}
for i := 0; i < n; i++ {
if !have[pos] {
have[pos] = true
count++
}
pos++
}
}
if !bytes.Equal(wantData, buf) {
t.Fatalf("want data %x, got %x", wantData, buf)
}
}
func TestNoSectionOverlaps(t *testing.T) {
// Ensure 6l outputs sections without overlaps.
if runtime.GOOS != "linux" && runtime.GOOS != "freebsd" {
......
src/debug/elf/reader.go 0 → 100644
View file @ 76483877
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package elf
import (
"io"
"os"
)
// errorReader returns error from all operations.
type errorReader struct {
error
}
func (r errorReader) Read(p []byte) (n int, err error) {
return 0, r.error
}
func (r errorReader) ReadAt(p []byte, off int64) (n int, err error) {
return 0, r.error
}
func (r errorReader) Seek(offset int64, whence int) (int64, error) {
return 0, r.error
}
func (r errorReader) Close() error {
return r.error
}
// readSeekerFromReader converts an io.Reader into an io.ReadSeeker.
// In general Seek may not be efficient, but it is optimized for
// common cases such as seeking to the end to find the length of the
// data.
type readSeekerFromReader struct {
reset func() (io.Reader, error)
r io.Reader
size int64
offset int64
}
func (r *readSeekerFromReader) start() {
x, err := r.reset()
if err != nil {
r.r = errorReader{err}
} else {
r.r = x
}
r.offset = 0
}
func (r *readSeekerFromReader) Read(p []byte) (n int, err error) {
if r.r == nil {
r.start()
}
n, err = r.r.Read(p)
r.offset += int64(n)
return n, err
}
func (r *readSeekerFromReader) Seek(offset int64, whence int) (int64, error) {
var newOffset int64
switch whence {
case 0:
newOffset = offset
case 1:
newOffset = r.offset + offset
case 2:
newOffset = r.size + offset
default:
return 0, os.ErrInvalid
}
switch {
case newOffset == r.offset:
return newOffset, nil
case newOffset < 0, newOffset > r.size:
return 0, os.ErrInvalid
case newOffset == 0:
r.r = nil
case newOffset == r.size:
r.r = errorReader{io.EOF}
default:
if newOffset < r.offset {
// Restart at the beginning.
r.start()
}
// Read until we reach offset.
var buf [512]byte
for r.offset < newOffset {
b := buf[:]
if newOffset-r.offset < int64(len(buf)) {
b = buf[:newOffset-r.offset]
}
if _, err := r.Read(b); err != nil {
return 0, err
}
}
}
r.offset = newOffset
return r.offset, nil
}
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