diff options
Diffstat (limited to 'src/debug/pe/section.go')
-rw-r--r-- | src/debug/pe/section.go | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/debug/pe/section.go b/src/debug/pe/section.go new file mode 100644 index 0000000..70d0c22 --- /dev/null +++ b/src/debug/pe/section.go @@ -0,0 +1,125 @@ +// Copyright 2016 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 pe + +import ( + "encoding/binary" + "fmt" + "internal/saferio" + "io" + "strconv" +) + +// SectionHeader32 represents real PE COFF section header. +type SectionHeader32 struct { + Name [8]uint8 + VirtualSize uint32 + VirtualAddress uint32 + SizeOfRawData uint32 + PointerToRawData uint32 + PointerToRelocations uint32 + PointerToLineNumbers uint32 + NumberOfRelocations uint16 + NumberOfLineNumbers uint16 + Characteristics uint32 +} + +// fullName finds real name of section sh. Normally name is stored +// in sh.Name, but if it is longer then 8 characters, it is stored +// in COFF string table st instead. +func (sh *SectionHeader32) fullName(st StringTable) (string, error) { + if sh.Name[0] != '/' { + return cstring(sh.Name[:]), nil + } + i, err := strconv.Atoi(cstring(sh.Name[1:])) + if err != nil { + return "", err + } + return st.String(uint32(i)) +} + +// TODO(brainman): copy all IMAGE_REL_* consts from ldpe.go here + +// Reloc represents a PE COFF relocation. +// Each section contains its own relocation list. +type Reloc struct { + VirtualAddress uint32 + SymbolTableIndex uint32 + Type uint16 +} + +func readRelocs(sh *SectionHeader, r io.ReadSeeker) ([]Reloc, error) { + if sh.NumberOfRelocations <= 0 { + return nil, nil + } + _, err := r.Seek(int64(sh.PointerToRelocations), seekStart) + if err != nil { + return nil, fmt.Errorf("fail to seek to %q section relocations: %v", sh.Name, err) + } + relocs := make([]Reloc, sh.NumberOfRelocations) + err = binary.Read(r, binary.LittleEndian, relocs) + if err != nil { + return nil, fmt.Errorf("fail to read section relocations: %v", err) + } + return relocs, nil +} + +// SectionHeader is similar to SectionHeader32 with Name +// field replaced by Go string. +type SectionHeader struct { + Name string + VirtualSize uint32 + VirtualAddress uint32 + Size uint32 + Offset uint32 + PointerToRelocations uint32 + PointerToLineNumbers uint32 + NumberOfRelocations uint16 + NumberOfLineNumbers uint16 + Characteristics uint32 +} + +// Section provides access to PE COFF section. +type Section struct { + SectionHeader + Relocs []Reloc + + // Embed ReaderAt for ReadAt method. + // Do not embed SectionReader directly + // to avoid having Read and Seek. + // If a client wants Read and Seek it must use + // Open() to avoid fighting over the seek offset + // with other clients. + io.ReaderAt + sr *io.SectionReader +} + +// Data reads and returns the contents of the PE section s. +// +// If s.Offset is 0, the section has no contents, +// and Data will always return a non-nil error. +func (s *Section) Data() ([]byte, error) { + return saferio.ReadDataAt(s.sr, uint64(s.Size), 0) +} + +// Open returns a new ReadSeeker reading the PE section s. +// +// If s.Offset is 0, the section has no contents, and all calls +// to the returned reader will return a non-nil error. +func (s *Section) Open() io.ReadSeeker { + return io.NewSectionReader(s.sr, 0, 1<<63-1) +} + +// Section characteristics flags. +const ( + IMAGE_SCN_CNT_CODE = 0x00000020 + IMAGE_SCN_CNT_INITIALIZED_DATA = 0x00000040 + IMAGE_SCN_CNT_UNINITIALIZED_DATA = 0x00000080 + IMAGE_SCN_LNK_COMDAT = 0x00001000 + IMAGE_SCN_MEM_DISCARDABLE = 0x02000000 + IMAGE_SCN_MEM_EXECUTE = 0x20000000 + IMAGE_SCN_MEM_READ = 0x40000000 + IMAGE_SCN_MEM_WRITE = 0x80000000 +) |