From 2f68519b3c6b5a70028882c99afeb76f291b7725 Mon Sep 17 00:00:00 2001 From: Wim Date: Thu, 23 Mar 2017 23:28:55 +0100 Subject: Add gops agent --- .../github.com/google/gops/internal/objfile/pe.go | 208 +++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 vendor/github.com/google/gops/internal/objfile/pe.go (limited to 'vendor/github.com/google/gops/internal/objfile/pe.go') diff --git a/vendor/github.com/google/gops/internal/objfile/pe.go b/vendor/github.com/google/gops/internal/objfile/pe.go new file mode 100644 index 00000000..46b23172 --- /dev/null +++ b/vendor/github.com/google/gops/internal/objfile/pe.go @@ -0,0 +1,208 @@ +// Copyright 2013 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. + +// Parsing of PE executables (Microsoft Windows). + +package objfile + +import ( + "debug/dwarf" + "debug/pe" + "fmt" + "os" + "sort" +) + +type peFile struct { + pe *pe.File +} + +func openPE(r *os.File) (rawFile, error) { + f, err := pe.NewFile(r) + if err != nil { + return nil, err + } + switch f.OptionalHeader.(type) { + case *pe.OptionalHeader32, *pe.OptionalHeader64: + // ok + default: + return nil, fmt.Errorf("unrecognized PE format") + } + return &peFile{f}, nil +} + +func (f *peFile) symbols() ([]Sym, error) { + // Build sorted list of addresses of all symbols. + // We infer the size of a symbol by looking at where the next symbol begins. + var addrs []uint64 + + var imageBase uint64 + switch oh := f.pe.OptionalHeader.(type) { + case *pe.OptionalHeader32: + imageBase = uint64(oh.ImageBase) + case *pe.OptionalHeader64: + imageBase = oh.ImageBase + } + + var syms []Sym + for _, s := range f.pe.Symbols { + const ( + N_UNDEF = 0 // An undefined (extern) symbol + N_ABS = -1 // An absolute symbol (e_value is a constant, not an address) + N_DEBUG = -2 // A debugging symbol + ) + sym := Sym{Name: s.Name, Addr: uint64(s.Value), Code: '?'} + switch s.SectionNumber { + case N_UNDEF: + sym.Code = 'U' + case N_ABS: + sym.Code = 'C' + case N_DEBUG: + sym.Code = '?' + default: + if s.SectionNumber < 0 || len(f.pe.Sections) < int(s.SectionNumber) { + return nil, fmt.Errorf("invalid section number in symbol table") + } + sect := f.pe.Sections[s.SectionNumber-1] + const ( + text = 0x20 + data = 0x40 + bss = 0x80 + permW = 0x80000000 + ) + ch := sect.Characteristics + switch { + case ch&text != 0: + sym.Code = 'T' + case ch&data != 0: + if ch&permW == 0 { + sym.Code = 'R' + } else { + sym.Code = 'D' + } + case ch&bss != 0: + sym.Code = 'B' + } + sym.Addr += imageBase + uint64(sect.VirtualAddress) + } + syms = append(syms, sym) + addrs = append(addrs, sym.Addr) + } + + sort.Sort(uint64s(addrs)) + for i := range syms { + j := sort.Search(len(addrs), func(x int) bool { return addrs[x] > syms[i].Addr }) + if j < len(addrs) { + syms[i].Size = int64(addrs[j] - syms[i].Addr) + } + } + + return syms, nil +} + +func (f *peFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) { + var imageBase uint64 + switch oh := f.pe.OptionalHeader.(type) { + case *pe.OptionalHeader32: + imageBase = uint64(oh.ImageBase) + case *pe.OptionalHeader64: + imageBase = oh.ImageBase + default: + return 0, nil, nil, fmt.Errorf("pe file format not recognized") + } + if sect := f.pe.Section(".text"); sect != nil { + textStart = imageBase + uint64(sect.VirtualAddress) + } + if pclntab, err = loadPETable(f.pe, "runtime.pclntab", "runtime.epclntab"); err != nil { + // We didn't find the symbols, so look for the names used in 1.3 and earlier. + // TODO: Remove code looking for the old symbols when we no longer care about 1.3. + var err2 error + if pclntab, err2 = loadPETable(f.pe, "pclntab", "epclntab"); err2 != nil { + return 0, nil, nil, err + } + } + if symtab, err = loadPETable(f.pe, "runtime.symtab", "runtime.esymtab"); err != nil { + // Same as above. + var err2 error + if symtab, err2 = loadPETable(f.pe, "symtab", "esymtab"); err2 != nil { + return 0, nil, nil, err + } + } + return textStart, symtab, pclntab, nil +} + +func (f *peFile) text() (textStart uint64, text []byte, err error) { + var imageBase uint64 + switch oh := f.pe.OptionalHeader.(type) { + case *pe.OptionalHeader32: + imageBase = uint64(oh.ImageBase) + case *pe.OptionalHeader64: + imageBase = oh.ImageBase + default: + return 0, nil, fmt.Errorf("pe file format not recognized") + } + sect := f.pe.Section(".text") + if sect == nil { + return 0, nil, fmt.Errorf("text section not found") + } + textStart = imageBase + uint64(sect.VirtualAddress) + text, err = sect.Data() + return +} + +func findPESymbol(f *pe.File, name string) (*pe.Symbol, error) { + for _, s := range f.Symbols { + if s.Name != name { + continue + } + if s.SectionNumber <= 0 { + return nil, fmt.Errorf("symbol %s: invalid section number %d", name, s.SectionNumber) + } + if len(f.Sections) < int(s.SectionNumber) { + return nil, fmt.Errorf("symbol %s: section number %d is larger than max %d", name, s.SectionNumber, len(f.Sections)) + } + return s, nil + } + return nil, fmt.Errorf("no %s symbol found", name) +} + +func loadPETable(f *pe.File, sname, ename string) ([]byte, error) { + ssym, err := findPESymbol(f, sname) + if err != nil { + return nil, err + } + esym, err := findPESymbol(f, ename) + if err != nil { + return nil, err + } + if ssym.SectionNumber != esym.SectionNumber { + return nil, fmt.Errorf("%s and %s symbols must be in the same section", sname, ename) + } + sect := f.Sections[ssym.SectionNumber-1] + data, err := sect.Data() + if err != nil { + return nil, err + } + return data[ssym.Value:esym.Value], nil +} + +func (f *peFile) goarch() string { + // Not sure how to get the info we want from PE header. + // Look in symbol table for telltale rt0 symbol. + if _, err := findPESymbol(f.pe, "_rt0_386_windows"); err == nil { + return "386" + } + if _, err := findPESymbol(f.pe, "_rt0_amd64_windows"); err == nil { + return "amd64" + } + return "" +} + +func (f *peFile) loadAddress() (uint64, error) { + return 0, fmt.Errorf("unknown load address") +} + +func (f *peFile) dwarf() (*dwarf.Data, error) { + return f.pe.DWARF() +} -- cgit v1.2.3