Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1 | // Copyright 2009 The Go Authors. All rights reserved. |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package elf implements access to ELF object files. |
| 6 | package elf |
| 7 | |
| 8 | import ( |
| 9 | "bytes" |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 10 | "compress/zlib" |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 11 | "debug/dwarf" |
| 12 | "encoding/binary" |
| 13 | "errors" |
| 14 | "fmt" |
| 15 | "io" |
| 16 | "os" |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 17 | "strings" |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 18 | ) |
| 19 | |
Dan Willemsen | a322328 | 2018-02-27 19:41:43 -0800 | [diff] [blame^] | 20 | // seekStart, seekCurrent, seekEnd are copies of |
| 21 | // io.SeekStart, io.SeekCurrent, and io.SeekEnd. |
| 22 | // We can't use the ones from package io because |
| 23 | // we want this code to build with Go 1.4 during |
| 24 | // cmd/dist bootstrap. |
| 25 | const ( |
| 26 | seekStart int = 0 |
| 27 | seekCurrent int = 1 |
| 28 | seekEnd int = 2 |
| 29 | ) |
| 30 | |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 31 | // TODO: error reporting detail |
| 32 | |
| 33 | /* |
| 34 | * Internal ELF representation |
| 35 | */ |
| 36 | |
| 37 | // A FileHeader represents an ELF file header. |
| 38 | type FileHeader struct { |
| 39 | Class Class |
| 40 | Data Data |
| 41 | Version Version |
| 42 | OSABI OSABI |
| 43 | ABIVersion uint8 |
| 44 | ByteOrder binary.ByteOrder |
| 45 | Type Type |
| 46 | Machine Machine |
| 47 | Entry uint64 |
| 48 | } |
| 49 | |
| 50 | // A File represents an open ELF file. |
| 51 | type File struct { |
| 52 | FileHeader |
| 53 | Sections []*Section |
| 54 | Progs []*Prog |
| 55 | closer io.Closer |
| 56 | gnuNeed []verneed |
| 57 | gnuVersym []byte |
| 58 | } |
| 59 | |
| 60 | // A SectionHeader represents a single ELF section header. |
| 61 | type SectionHeader struct { |
| 62 | Name string |
| 63 | Type SectionType |
| 64 | Flags SectionFlag |
| 65 | Addr uint64 |
| 66 | Offset uint64 |
| 67 | Size uint64 |
| 68 | Link uint32 |
| 69 | Info uint32 |
| 70 | Addralign uint64 |
| 71 | Entsize uint64 |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 72 | |
| 73 | // FileSize is the size of this section in the file in bytes. |
| 74 | // If a section is compressed, FileSize is the size of the |
| 75 | // compressed data, while Size (above) is the size of the |
| 76 | // uncompressed data. |
| 77 | FileSize uint64 |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 78 | } |
| 79 | |
| 80 | // A Section represents a single section in an ELF file. |
| 81 | type Section struct { |
| 82 | SectionHeader |
| 83 | |
| 84 | // Embed ReaderAt for ReadAt method. |
| 85 | // Do not embed SectionReader directly |
| 86 | // to avoid having Read and Seek. |
| 87 | // If a client wants Read and Seek it must use |
| 88 | // Open() to avoid fighting over the seek offset |
| 89 | // with other clients. |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 90 | // |
| 91 | // ReaderAt may be nil if the section is not easily available |
| 92 | // in a random-access form. For example, a compressed section |
| 93 | // may have a nil ReaderAt. |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 94 | io.ReaderAt |
| 95 | sr *io.SectionReader |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 96 | |
| 97 | compressionType CompressionType |
| 98 | compressionOffset int64 |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 99 | } |
| 100 | |
| 101 | // Data reads and returns the contents of the ELF section. |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 102 | // Even if the section is stored compressed in the ELF file, |
| 103 | // Data returns uncompressed data. |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 104 | func (s *Section) Data() ([]byte, error) { |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 105 | dat := make([]byte, s.Size) |
| 106 | n, err := io.ReadFull(s.Open(), dat) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 107 | return dat[0:n], err |
| 108 | } |
| 109 | |
| 110 | // stringTable reads and returns the string table given by the |
| 111 | // specified link value. |
| 112 | func (f *File) stringTable(link uint32) ([]byte, error) { |
| 113 | if link <= 0 || link >= uint32(len(f.Sections)) { |
| 114 | return nil, errors.New("section has invalid string table link") |
| 115 | } |
| 116 | return f.Sections[link].Data() |
| 117 | } |
| 118 | |
| 119 | // Open returns a new ReadSeeker reading the ELF section. |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 120 | // Even if the section is stored compressed in the ELF file, |
| 121 | // the ReadSeeker reads uncompressed data. |
| 122 | func (s *Section) Open() io.ReadSeeker { |
| 123 | if s.Flags&SHF_COMPRESSED == 0 { |
| 124 | return io.NewSectionReader(s.sr, 0, 1<<63-1) |
| 125 | } |
| 126 | if s.compressionType == COMPRESS_ZLIB { |
| 127 | return &readSeekerFromReader{ |
| 128 | reset: func() (io.Reader, error) { |
| 129 | fr := io.NewSectionReader(s.sr, s.compressionOffset, int64(s.FileSize)-s.compressionOffset) |
| 130 | return zlib.NewReader(fr) |
| 131 | }, |
| 132 | size: int64(s.Size), |
| 133 | } |
| 134 | } |
| 135 | err := &FormatError{int64(s.Offset), "unknown compression type", s.compressionType} |
| 136 | return errorReader{err} |
| 137 | } |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 138 | |
| 139 | // A ProgHeader represents a single ELF program header. |
| 140 | type ProgHeader struct { |
| 141 | Type ProgType |
| 142 | Flags ProgFlag |
| 143 | Off uint64 |
| 144 | Vaddr uint64 |
| 145 | Paddr uint64 |
| 146 | Filesz uint64 |
| 147 | Memsz uint64 |
| 148 | Align uint64 |
| 149 | } |
| 150 | |
| 151 | // A Prog represents a single ELF program header in an ELF binary. |
| 152 | type Prog struct { |
| 153 | ProgHeader |
| 154 | |
| 155 | // Embed ReaderAt for ReadAt method. |
| 156 | // Do not embed SectionReader directly |
| 157 | // to avoid having Read and Seek. |
| 158 | // If a client wants Read and Seek it must use |
| 159 | // Open() to avoid fighting over the seek offset |
| 160 | // with other clients. |
| 161 | io.ReaderAt |
| 162 | sr *io.SectionReader |
| 163 | } |
| 164 | |
| 165 | // Open returns a new ReadSeeker reading the ELF program body. |
| 166 | func (p *Prog) Open() io.ReadSeeker { return io.NewSectionReader(p.sr, 0, 1<<63-1) } |
| 167 | |
| 168 | // A Symbol represents an entry in an ELF symbol table section. |
| 169 | type Symbol struct { |
| 170 | Name string |
| 171 | Info, Other byte |
| 172 | Section SectionIndex |
| 173 | Value, Size uint64 |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * ELF reader |
| 178 | */ |
| 179 | |
| 180 | type FormatError struct { |
| 181 | off int64 |
| 182 | msg string |
| 183 | val interface{} |
| 184 | } |
| 185 | |
| 186 | func (e *FormatError) Error() string { |
| 187 | msg := e.msg |
| 188 | if e.val != nil { |
| 189 | msg += fmt.Sprintf(" '%v' ", e.val) |
| 190 | } |
| 191 | msg += fmt.Sprintf("in record at byte %#x", e.off) |
| 192 | return msg |
| 193 | } |
| 194 | |
| 195 | // Open opens the named file using os.Open and prepares it for use as an ELF binary. |
| 196 | func Open(name string) (*File, error) { |
| 197 | f, err := os.Open(name) |
| 198 | if err != nil { |
| 199 | return nil, err |
| 200 | } |
| 201 | ff, err := NewFile(f) |
| 202 | if err != nil { |
| 203 | f.Close() |
| 204 | return nil, err |
| 205 | } |
| 206 | ff.closer = f |
| 207 | return ff, nil |
| 208 | } |
| 209 | |
| 210 | // Close closes the File. |
| 211 | // If the File was created using NewFile directly instead of Open, |
| 212 | // Close has no effect. |
| 213 | func (f *File) Close() error { |
| 214 | var err error |
| 215 | if f.closer != nil { |
| 216 | err = f.closer.Close() |
| 217 | f.closer = nil |
| 218 | } |
| 219 | return err |
| 220 | } |
| 221 | |
| 222 | // SectionByType returns the first section in f with the |
| 223 | // given type, or nil if there is no such section. |
| 224 | func (f *File) SectionByType(typ SectionType) *Section { |
| 225 | for _, s := range f.Sections { |
| 226 | if s.Type == typ { |
| 227 | return s |
| 228 | } |
| 229 | } |
| 230 | return nil |
| 231 | } |
| 232 | |
| 233 | // NewFile creates a new File for accessing an ELF binary in an underlying reader. |
| 234 | // The ELF binary is expected to start at position 0 in the ReaderAt. |
| 235 | func NewFile(r io.ReaderAt) (*File, error) { |
| 236 | sr := io.NewSectionReader(r, 0, 1<<63-1) |
| 237 | // Read and decode ELF identifier |
| 238 | var ident [16]uint8 |
| 239 | if _, err := r.ReadAt(ident[0:], 0); err != nil { |
| 240 | return nil, err |
| 241 | } |
| 242 | if ident[0] != '\x7f' || ident[1] != 'E' || ident[2] != 'L' || ident[3] != 'F' { |
| 243 | return nil, &FormatError{0, "bad magic number", ident[0:4]} |
| 244 | } |
| 245 | |
| 246 | f := new(File) |
| 247 | f.Class = Class(ident[EI_CLASS]) |
| 248 | switch f.Class { |
| 249 | case ELFCLASS32: |
| 250 | case ELFCLASS64: |
| 251 | // ok |
| 252 | default: |
| 253 | return nil, &FormatError{0, "unknown ELF class", f.Class} |
| 254 | } |
| 255 | |
| 256 | f.Data = Data(ident[EI_DATA]) |
| 257 | switch f.Data { |
| 258 | case ELFDATA2LSB: |
| 259 | f.ByteOrder = binary.LittleEndian |
| 260 | case ELFDATA2MSB: |
| 261 | f.ByteOrder = binary.BigEndian |
| 262 | default: |
| 263 | return nil, &FormatError{0, "unknown ELF data encoding", f.Data} |
| 264 | } |
| 265 | |
| 266 | f.Version = Version(ident[EI_VERSION]) |
| 267 | if f.Version != EV_CURRENT { |
| 268 | return nil, &FormatError{0, "unknown ELF version", f.Version} |
| 269 | } |
| 270 | |
| 271 | f.OSABI = OSABI(ident[EI_OSABI]) |
| 272 | f.ABIVersion = ident[EI_ABIVERSION] |
| 273 | |
| 274 | // Read ELF file header |
| 275 | var phoff int64 |
| 276 | var phentsize, phnum int |
| 277 | var shoff int64 |
| 278 | var shentsize, shnum, shstrndx int |
| 279 | shstrndx = -1 |
| 280 | switch f.Class { |
| 281 | case ELFCLASS32: |
| 282 | hdr := new(Header32) |
Dan Willemsen | a322328 | 2018-02-27 19:41:43 -0800 | [diff] [blame^] | 283 | sr.Seek(0, seekStart) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 284 | if err := binary.Read(sr, f.ByteOrder, hdr); err != nil { |
| 285 | return nil, err |
| 286 | } |
| 287 | f.Type = Type(hdr.Type) |
| 288 | f.Machine = Machine(hdr.Machine) |
| 289 | f.Entry = uint64(hdr.Entry) |
| 290 | if v := Version(hdr.Version); v != f.Version { |
| 291 | return nil, &FormatError{0, "mismatched ELF version", v} |
| 292 | } |
| 293 | phoff = int64(hdr.Phoff) |
| 294 | phentsize = int(hdr.Phentsize) |
| 295 | phnum = int(hdr.Phnum) |
| 296 | shoff = int64(hdr.Shoff) |
| 297 | shentsize = int(hdr.Shentsize) |
| 298 | shnum = int(hdr.Shnum) |
| 299 | shstrndx = int(hdr.Shstrndx) |
| 300 | case ELFCLASS64: |
| 301 | hdr := new(Header64) |
Dan Willemsen | a322328 | 2018-02-27 19:41:43 -0800 | [diff] [blame^] | 302 | sr.Seek(0, seekStart) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 303 | if err := binary.Read(sr, f.ByteOrder, hdr); err != nil { |
| 304 | return nil, err |
| 305 | } |
| 306 | f.Type = Type(hdr.Type) |
| 307 | f.Machine = Machine(hdr.Machine) |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 308 | f.Entry = hdr.Entry |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 309 | if v := Version(hdr.Version); v != f.Version { |
| 310 | return nil, &FormatError{0, "mismatched ELF version", v} |
| 311 | } |
| 312 | phoff = int64(hdr.Phoff) |
| 313 | phentsize = int(hdr.Phentsize) |
| 314 | phnum = int(hdr.Phnum) |
| 315 | shoff = int64(hdr.Shoff) |
| 316 | shentsize = int(hdr.Shentsize) |
| 317 | shnum = int(hdr.Shnum) |
| 318 | shstrndx = int(hdr.Shstrndx) |
| 319 | } |
| 320 | |
| 321 | if shnum > 0 && shoff > 0 && (shstrndx < 0 || shstrndx >= shnum) { |
| 322 | return nil, &FormatError{0, "invalid ELF shstrndx", shstrndx} |
| 323 | } |
| 324 | |
| 325 | // Read program headers |
| 326 | f.Progs = make([]*Prog, phnum) |
| 327 | for i := 0; i < phnum; i++ { |
| 328 | off := phoff + int64(i)*int64(phentsize) |
Dan Willemsen | a322328 | 2018-02-27 19:41:43 -0800 | [diff] [blame^] | 329 | sr.Seek(off, seekStart) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 330 | p := new(Prog) |
| 331 | switch f.Class { |
| 332 | case ELFCLASS32: |
| 333 | ph := new(Prog32) |
| 334 | if err := binary.Read(sr, f.ByteOrder, ph); err != nil { |
| 335 | return nil, err |
| 336 | } |
| 337 | p.ProgHeader = ProgHeader{ |
| 338 | Type: ProgType(ph.Type), |
| 339 | Flags: ProgFlag(ph.Flags), |
| 340 | Off: uint64(ph.Off), |
| 341 | Vaddr: uint64(ph.Vaddr), |
| 342 | Paddr: uint64(ph.Paddr), |
| 343 | Filesz: uint64(ph.Filesz), |
| 344 | Memsz: uint64(ph.Memsz), |
| 345 | Align: uint64(ph.Align), |
| 346 | } |
| 347 | case ELFCLASS64: |
| 348 | ph := new(Prog64) |
| 349 | if err := binary.Read(sr, f.ByteOrder, ph); err != nil { |
| 350 | return nil, err |
| 351 | } |
| 352 | p.ProgHeader = ProgHeader{ |
| 353 | Type: ProgType(ph.Type), |
| 354 | Flags: ProgFlag(ph.Flags), |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 355 | Off: ph.Off, |
| 356 | Vaddr: ph.Vaddr, |
| 357 | Paddr: ph.Paddr, |
| 358 | Filesz: ph.Filesz, |
| 359 | Memsz: ph.Memsz, |
| 360 | Align: ph.Align, |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 361 | } |
| 362 | } |
| 363 | p.sr = io.NewSectionReader(r, int64(p.Off), int64(p.Filesz)) |
| 364 | p.ReaderAt = p.sr |
| 365 | f.Progs[i] = p |
| 366 | } |
| 367 | |
| 368 | // Read section headers |
| 369 | f.Sections = make([]*Section, shnum) |
| 370 | names := make([]uint32, shnum) |
| 371 | for i := 0; i < shnum; i++ { |
| 372 | off := shoff + int64(i)*int64(shentsize) |
Dan Willemsen | a322328 | 2018-02-27 19:41:43 -0800 | [diff] [blame^] | 373 | sr.Seek(off, seekStart) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 374 | s := new(Section) |
| 375 | switch f.Class { |
| 376 | case ELFCLASS32: |
| 377 | sh := new(Section32) |
| 378 | if err := binary.Read(sr, f.ByteOrder, sh); err != nil { |
| 379 | return nil, err |
| 380 | } |
| 381 | names[i] = sh.Name |
| 382 | s.SectionHeader = SectionHeader{ |
| 383 | Type: SectionType(sh.Type), |
| 384 | Flags: SectionFlag(sh.Flags), |
| 385 | Addr: uint64(sh.Addr), |
| 386 | Offset: uint64(sh.Off), |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 387 | FileSize: uint64(sh.Size), |
| 388 | Link: sh.Link, |
| 389 | Info: sh.Info, |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 390 | Addralign: uint64(sh.Addralign), |
| 391 | Entsize: uint64(sh.Entsize), |
| 392 | } |
| 393 | case ELFCLASS64: |
| 394 | sh := new(Section64) |
| 395 | if err := binary.Read(sr, f.ByteOrder, sh); err != nil { |
| 396 | return nil, err |
| 397 | } |
| 398 | names[i] = sh.Name |
| 399 | s.SectionHeader = SectionHeader{ |
| 400 | Type: SectionType(sh.Type), |
| 401 | Flags: SectionFlag(sh.Flags), |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 402 | Offset: sh.Off, |
| 403 | FileSize: sh.Size, |
| 404 | Addr: sh.Addr, |
| 405 | Link: sh.Link, |
| 406 | Info: sh.Info, |
| 407 | Addralign: sh.Addralign, |
| 408 | Entsize: sh.Entsize, |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 409 | } |
| 410 | } |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 411 | s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.FileSize)) |
| 412 | |
| 413 | if s.Flags&SHF_COMPRESSED == 0 { |
| 414 | s.ReaderAt = s.sr |
| 415 | s.Size = s.FileSize |
| 416 | } else { |
| 417 | // Read the compression header. |
| 418 | switch f.Class { |
| 419 | case ELFCLASS32: |
| 420 | ch := new(Chdr32) |
| 421 | if err := binary.Read(s.sr, f.ByteOrder, ch); err != nil { |
| 422 | return nil, err |
| 423 | } |
| 424 | s.compressionType = CompressionType(ch.Type) |
| 425 | s.Size = uint64(ch.Size) |
| 426 | s.Addralign = uint64(ch.Addralign) |
| 427 | s.compressionOffset = int64(binary.Size(ch)) |
| 428 | case ELFCLASS64: |
| 429 | ch := new(Chdr64) |
| 430 | if err := binary.Read(s.sr, f.ByteOrder, ch); err != nil { |
| 431 | return nil, err |
| 432 | } |
| 433 | s.compressionType = CompressionType(ch.Type) |
| 434 | s.Size = ch.Size |
| 435 | s.Addralign = ch.Addralign |
| 436 | s.compressionOffset = int64(binary.Size(ch)) |
| 437 | } |
| 438 | } |
| 439 | |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 440 | f.Sections[i] = s |
| 441 | } |
| 442 | |
| 443 | if len(f.Sections) == 0 { |
| 444 | return f, nil |
| 445 | } |
| 446 | |
| 447 | // Load section header string table. |
| 448 | shstrtab, err := f.Sections[shstrndx].Data() |
| 449 | if err != nil { |
| 450 | return nil, err |
| 451 | } |
| 452 | for i, s := range f.Sections { |
| 453 | var ok bool |
| 454 | s.Name, ok = getString(shstrtab, int(names[i])) |
| 455 | if !ok { |
| 456 | return nil, &FormatError{shoff + int64(i*shentsize), "bad section name index", names[i]} |
| 457 | } |
| 458 | } |
| 459 | |
| 460 | return f, nil |
| 461 | } |
| 462 | |
| 463 | // getSymbols returns a slice of Symbols from parsing the symbol table |
| 464 | // with the given type, along with the associated string table. |
| 465 | func (f *File) getSymbols(typ SectionType) ([]Symbol, []byte, error) { |
| 466 | switch f.Class { |
| 467 | case ELFCLASS64: |
| 468 | return f.getSymbols64(typ) |
| 469 | |
| 470 | case ELFCLASS32: |
| 471 | return f.getSymbols32(typ) |
| 472 | } |
| 473 | |
| 474 | return nil, nil, errors.New("not implemented") |
| 475 | } |
| 476 | |
| 477 | // ErrNoSymbols is returned by File.Symbols and File.DynamicSymbols |
| 478 | // if there is no such section in the File. |
| 479 | var ErrNoSymbols = errors.New("no symbol section") |
| 480 | |
| 481 | func (f *File) getSymbols32(typ SectionType) ([]Symbol, []byte, error) { |
| 482 | symtabSection := f.SectionByType(typ) |
| 483 | if symtabSection == nil { |
| 484 | return nil, nil, ErrNoSymbols |
| 485 | } |
| 486 | |
| 487 | data, err := symtabSection.Data() |
| 488 | if err != nil { |
| 489 | return nil, nil, errors.New("cannot load symbol section") |
| 490 | } |
| 491 | symtab := bytes.NewReader(data) |
| 492 | if symtab.Len()%Sym32Size != 0 { |
| 493 | return nil, nil, errors.New("length of symbol section is not a multiple of SymSize") |
| 494 | } |
| 495 | |
| 496 | strdata, err := f.stringTable(symtabSection.Link) |
| 497 | if err != nil { |
| 498 | return nil, nil, errors.New("cannot load string table section") |
| 499 | } |
| 500 | |
| 501 | // The first entry is all zeros. |
| 502 | var skip [Sym32Size]byte |
| 503 | symtab.Read(skip[:]) |
| 504 | |
| 505 | symbols := make([]Symbol, symtab.Len()/Sym32Size) |
| 506 | |
| 507 | i := 0 |
| 508 | var sym Sym32 |
| 509 | for symtab.Len() > 0 { |
| 510 | binary.Read(symtab, f.ByteOrder, &sym) |
| 511 | str, _ := getString(strdata, int(sym.Name)) |
| 512 | symbols[i].Name = str |
| 513 | symbols[i].Info = sym.Info |
| 514 | symbols[i].Other = sym.Other |
| 515 | symbols[i].Section = SectionIndex(sym.Shndx) |
| 516 | symbols[i].Value = uint64(sym.Value) |
| 517 | symbols[i].Size = uint64(sym.Size) |
| 518 | i++ |
| 519 | } |
| 520 | |
| 521 | return symbols, strdata, nil |
| 522 | } |
| 523 | |
| 524 | func (f *File) getSymbols64(typ SectionType) ([]Symbol, []byte, error) { |
| 525 | symtabSection := f.SectionByType(typ) |
| 526 | if symtabSection == nil { |
| 527 | return nil, nil, ErrNoSymbols |
| 528 | } |
| 529 | |
| 530 | data, err := symtabSection.Data() |
| 531 | if err != nil { |
| 532 | return nil, nil, errors.New("cannot load symbol section") |
| 533 | } |
| 534 | symtab := bytes.NewReader(data) |
| 535 | if symtab.Len()%Sym64Size != 0 { |
| 536 | return nil, nil, errors.New("length of symbol section is not a multiple of Sym64Size") |
| 537 | } |
| 538 | |
| 539 | strdata, err := f.stringTable(symtabSection.Link) |
| 540 | if err != nil { |
| 541 | return nil, nil, errors.New("cannot load string table section") |
| 542 | } |
| 543 | |
| 544 | // The first entry is all zeros. |
| 545 | var skip [Sym64Size]byte |
| 546 | symtab.Read(skip[:]) |
| 547 | |
| 548 | symbols := make([]Symbol, symtab.Len()/Sym64Size) |
| 549 | |
| 550 | i := 0 |
| 551 | var sym Sym64 |
| 552 | for symtab.Len() > 0 { |
| 553 | binary.Read(symtab, f.ByteOrder, &sym) |
| 554 | str, _ := getString(strdata, int(sym.Name)) |
| 555 | symbols[i].Name = str |
| 556 | symbols[i].Info = sym.Info |
| 557 | symbols[i].Other = sym.Other |
| 558 | symbols[i].Section = SectionIndex(sym.Shndx) |
| 559 | symbols[i].Value = sym.Value |
| 560 | symbols[i].Size = sym.Size |
| 561 | i++ |
| 562 | } |
| 563 | |
| 564 | return symbols, strdata, nil |
| 565 | } |
| 566 | |
| 567 | // getString extracts a string from an ELF string table. |
| 568 | func getString(section []byte, start int) (string, bool) { |
| 569 | if start < 0 || start >= len(section) { |
| 570 | return "", false |
| 571 | } |
| 572 | |
| 573 | for end := start; end < len(section); end++ { |
| 574 | if section[end] == 0 { |
| 575 | return string(section[start:end]), true |
| 576 | } |
| 577 | } |
| 578 | return "", false |
| 579 | } |
| 580 | |
| 581 | // Section returns a section with the given name, or nil if no such |
| 582 | // section exists. |
| 583 | func (f *File) Section(name string) *Section { |
| 584 | for _, s := range f.Sections { |
| 585 | if s.Name == name { |
| 586 | return s |
| 587 | } |
| 588 | } |
| 589 | return nil |
| 590 | } |
| 591 | |
| 592 | // applyRelocations applies relocations to dst. rels is a relocations section |
Dan Willemsen | ebae302 | 2017-01-13 23:01:08 -0800 | [diff] [blame] | 593 | // in REL or RELA format. |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 594 | func (f *File) applyRelocations(dst []byte, rels []byte) error { |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 595 | switch { |
| 596 | case f.Class == ELFCLASS64 && f.Machine == EM_X86_64: |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 597 | return f.applyRelocationsAMD64(dst, rels) |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 598 | case f.Class == ELFCLASS32 && f.Machine == EM_386: |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 599 | return f.applyRelocations386(dst, rels) |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 600 | case f.Class == ELFCLASS32 && f.Machine == EM_ARM: |
| 601 | return f.applyRelocationsARM(dst, rels) |
| 602 | case f.Class == ELFCLASS64 && f.Machine == EM_AARCH64: |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 603 | return f.applyRelocationsARM64(dst, rels) |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 604 | case f.Class == ELFCLASS32 && f.Machine == EM_PPC: |
| 605 | return f.applyRelocationsPPC(dst, rels) |
| 606 | case f.Class == ELFCLASS64 && f.Machine == EM_PPC64: |
| 607 | return f.applyRelocationsPPC64(dst, rels) |
Dan Willemsen | ebae302 | 2017-01-13 23:01:08 -0800 | [diff] [blame] | 608 | case f.Class == ELFCLASS32 && f.Machine == EM_MIPS: |
| 609 | return f.applyRelocationsMIPS(dst, rels) |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 610 | case f.Class == ELFCLASS64 && f.Machine == EM_MIPS: |
| 611 | return f.applyRelocationsMIPS64(dst, rels) |
| 612 | case f.Class == ELFCLASS64 && f.Machine == EM_S390: |
| 613 | return f.applyRelocationss390x(dst, rels) |
Dan Willemsen | ebae302 | 2017-01-13 23:01:08 -0800 | [diff] [blame] | 614 | case f.Class == ELFCLASS64 && f.Machine == EM_SPARCV9: |
| 615 | return f.applyRelocationsSPARC64(dst, rels) |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 616 | default: |
| 617 | return errors.New("applyRelocations: not implemented") |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 618 | } |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 619 | } |
| 620 | |
| 621 | func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) error { |
| 622 | // 24 is the size of Rela64. |
| 623 | if len(rels)%24 != 0 { |
| 624 | return errors.New("length of relocation section is not a multiple of 24") |
| 625 | } |
| 626 | |
| 627 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 628 | if err != nil { |
| 629 | return err |
| 630 | } |
| 631 | |
| 632 | b := bytes.NewReader(rels) |
| 633 | var rela Rela64 |
| 634 | |
| 635 | for b.Len() > 0 { |
| 636 | binary.Read(b, f.ByteOrder, &rela) |
| 637 | symNo := rela.Info >> 32 |
| 638 | t := R_X86_64(rela.Info & 0xffff) |
| 639 | |
| 640 | if symNo == 0 || symNo > uint64(len(symbols)) { |
| 641 | continue |
| 642 | } |
| 643 | sym := &symbols[symNo-1] |
| 644 | if SymType(sym.Info&0xf) != STT_SECTION { |
| 645 | // We don't handle non-section relocations for now. |
| 646 | continue |
| 647 | } |
| 648 | |
| 649 | // There are relocations, so this must be a normal |
| 650 | // object file, and we only look at section symbols, |
| 651 | // so we assume that the symbol value is 0. |
| 652 | |
| 653 | switch t { |
| 654 | case R_X86_64_64: |
| 655 | if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { |
| 656 | continue |
| 657 | } |
| 658 | f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend)) |
| 659 | case R_X86_64_32: |
| 660 | if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { |
| 661 | continue |
| 662 | } |
| 663 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)) |
| 664 | } |
| 665 | } |
| 666 | |
| 667 | return nil |
| 668 | } |
| 669 | |
| 670 | func (f *File) applyRelocations386(dst []byte, rels []byte) error { |
| 671 | // 8 is the size of Rel32. |
| 672 | if len(rels)%8 != 0 { |
| 673 | return errors.New("length of relocation section is not a multiple of 8") |
| 674 | } |
| 675 | |
| 676 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 677 | if err != nil { |
| 678 | return err |
| 679 | } |
| 680 | |
| 681 | b := bytes.NewReader(rels) |
| 682 | var rel Rel32 |
| 683 | |
| 684 | for b.Len() > 0 { |
| 685 | binary.Read(b, f.ByteOrder, &rel) |
| 686 | symNo := rel.Info >> 8 |
| 687 | t := R_386(rel.Info & 0xff) |
| 688 | |
| 689 | if symNo == 0 || symNo > uint32(len(symbols)) { |
| 690 | continue |
| 691 | } |
| 692 | sym := &symbols[symNo-1] |
| 693 | |
| 694 | if t == R_386_32 { |
| 695 | if rel.Off+4 >= uint32(len(dst)) { |
| 696 | continue |
| 697 | } |
| 698 | val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4]) |
| 699 | val += uint32(sym.Value) |
| 700 | f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val) |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | return nil |
| 705 | } |
| 706 | |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 707 | func (f *File) applyRelocationsARM(dst []byte, rels []byte) error { |
| 708 | // 8 is the size of Rel32. |
| 709 | if len(rels)%8 != 0 { |
| 710 | return errors.New("length of relocation section is not a multiple of 8") |
| 711 | } |
| 712 | |
| 713 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 714 | if err != nil { |
| 715 | return err |
| 716 | } |
| 717 | |
| 718 | b := bytes.NewReader(rels) |
| 719 | var rel Rel32 |
| 720 | |
| 721 | for b.Len() > 0 { |
| 722 | binary.Read(b, f.ByteOrder, &rel) |
| 723 | symNo := rel.Info >> 8 |
| 724 | t := R_ARM(rel.Info & 0xff) |
| 725 | |
| 726 | if symNo == 0 || symNo > uint32(len(symbols)) { |
| 727 | continue |
| 728 | } |
| 729 | sym := &symbols[symNo-1] |
| 730 | |
| 731 | switch t { |
| 732 | case R_ARM_ABS32: |
| 733 | if rel.Off+4 >= uint32(len(dst)) { |
| 734 | continue |
| 735 | } |
| 736 | val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4]) |
| 737 | val += uint32(sym.Value) |
| 738 | f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val) |
| 739 | } |
| 740 | } |
| 741 | |
| 742 | return nil |
| 743 | } |
| 744 | |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 745 | func (f *File) applyRelocationsARM64(dst []byte, rels []byte) error { |
| 746 | // 24 is the size of Rela64. |
| 747 | if len(rels)%24 != 0 { |
| 748 | return errors.New("length of relocation section is not a multiple of 24") |
| 749 | } |
| 750 | |
| 751 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 752 | if err != nil { |
| 753 | return err |
| 754 | } |
| 755 | |
| 756 | b := bytes.NewReader(rels) |
| 757 | var rela Rela64 |
| 758 | |
| 759 | for b.Len() > 0 { |
| 760 | binary.Read(b, f.ByteOrder, &rela) |
| 761 | symNo := rela.Info >> 32 |
| 762 | t := R_AARCH64(rela.Info & 0xffff) |
| 763 | |
| 764 | if symNo == 0 || symNo > uint64(len(symbols)) { |
| 765 | continue |
| 766 | } |
| 767 | sym := &symbols[symNo-1] |
| 768 | if SymType(sym.Info&0xf) != STT_SECTION { |
| 769 | // We don't handle non-section relocations for now. |
| 770 | continue |
| 771 | } |
| 772 | |
| 773 | // There are relocations, so this must be a normal |
| 774 | // object file, and we only look at section symbols, |
| 775 | // so we assume that the symbol value is 0. |
| 776 | |
| 777 | switch t { |
| 778 | case R_AARCH64_ABS64: |
| 779 | if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { |
| 780 | continue |
| 781 | } |
| 782 | f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend)) |
| 783 | case R_AARCH64_ABS32: |
| 784 | if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { |
| 785 | continue |
| 786 | } |
| 787 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)) |
| 788 | } |
| 789 | } |
| 790 | |
| 791 | return nil |
| 792 | } |
| 793 | |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 794 | func (f *File) applyRelocationsPPC(dst []byte, rels []byte) error { |
| 795 | // 12 is the size of Rela32. |
| 796 | if len(rels)%12 != 0 { |
| 797 | return errors.New("length of relocation section is not a multiple of 12") |
| 798 | } |
| 799 | |
| 800 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 801 | if err != nil { |
| 802 | return err |
| 803 | } |
| 804 | |
| 805 | b := bytes.NewReader(rels) |
| 806 | var rela Rela32 |
| 807 | |
| 808 | for b.Len() > 0 { |
| 809 | binary.Read(b, f.ByteOrder, &rela) |
| 810 | symNo := rela.Info >> 8 |
| 811 | t := R_PPC(rela.Info & 0xff) |
| 812 | |
| 813 | if symNo == 0 || symNo > uint32(len(symbols)) { |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 814 | continue |
| 815 | } |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 816 | sym := &symbols[symNo-1] |
| 817 | if SymType(sym.Info&0xf) != STT_SECTION { |
| 818 | // We don't handle non-section relocations for now. |
| 819 | continue |
| 820 | } |
| 821 | |
| 822 | switch t { |
| 823 | case R_PPC_ADDR32: |
| 824 | if rela.Off+4 >= uint32(len(dst)) || rela.Addend < 0 { |
| 825 | continue |
| 826 | } |
| 827 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)) |
| 828 | } |
| 829 | } |
| 830 | |
| 831 | return nil |
| 832 | } |
| 833 | |
| 834 | func (f *File) applyRelocationsPPC64(dst []byte, rels []byte) error { |
| 835 | // 24 is the size of Rela64. |
| 836 | if len(rels)%24 != 0 { |
| 837 | return errors.New("length of relocation section is not a multiple of 24") |
| 838 | } |
| 839 | |
| 840 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 841 | if err != nil { |
| 842 | return err |
| 843 | } |
| 844 | |
| 845 | b := bytes.NewReader(rels) |
| 846 | var rela Rela64 |
| 847 | |
| 848 | for b.Len() > 0 { |
| 849 | binary.Read(b, f.ByteOrder, &rela) |
| 850 | symNo := rela.Info >> 32 |
| 851 | t := R_PPC64(rela.Info & 0xffff) |
| 852 | |
| 853 | if symNo == 0 || symNo > uint64(len(symbols)) { |
| 854 | continue |
| 855 | } |
| 856 | sym := &symbols[symNo-1] |
| 857 | if SymType(sym.Info&0xf) != STT_SECTION { |
| 858 | // We don't handle non-section relocations for now. |
| 859 | continue |
| 860 | } |
| 861 | |
| 862 | switch t { |
| 863 | case R_PPC64_ADDR64: |
| 864 | if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { |
| 865 | continue |
| 866 | } |
| 867 | f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend)) |
| 868 | case R_PPC64_ADDR32: |
| 869 | if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { |
| 870 | continue |
| 871 | } |
| 872 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)) |
| 873 | } |
| 874 | } |
| 875 | |
| 876 | return nil |
| 877 | } |
| 878 | |
Dan Willemsen | ebae302 | 2017-01-13 23:01:08 -0800 | [diff] [blame] | 879 | func (f *File) applyRelocationsMIPS(dst []byte, rels []byte) error { |
| 880 | // 8 is the size of Rel32. |
| 881 | if len(rels)%8 != 0 { |
| 882 | return errors.New("length of relocation section is not a multiple of 8") |
| 883 | } |
| 884 | |
| 885 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 886 | if err != nil { |
| 887 | return err |
| 888 | } |
| 889 | |
| 890 | b := bytes.NewReader(rels) |
| 891 | var rel Rel32 |
| 892 | |
| 893 | for b.Len() > 0 { |
| 894 | binary.Read(b, f.ByteOrder, &rel) |
| 895 | symNo := rel.Info >> 8 |
| 896 | t := R_MIPS(rel.Info & 0xff) |
| 897 | |
| 898 | if symNo == 0 || symNo > uint32(len(symbols)) { |
| 899 | continue |
| 900 | } |
| 901 | sym := &symbols[symNo-1] |
| 902 | |
| 903 | switch t { |
| 904 | case R_MIPS_32: |
| 905 | if rel.Off+4 >= uint32(len(dst)) { |
| 906 | continue |
| 907 | } |
| 908 | val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4]) |
| 909 | val += uint32(sym.Value) |
| 910 | f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val) |
| 911 | } |
| 912 | } |
| 913 | |
| 914 | return nil |
| 915 | } |
| 916 | |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 917 | func (f *File) applyRelocationsMIPS64(dst []byte, rels []byte) error { |
| 918 | // 24 is the size of Rela64. |
| 919 | if len(rels)%24 != 0 { |
| 920 | return errors.New("length of relocation section is not a multiple of 24") |
| 921 | } |
| 922 | |
| 923 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 924 | if err != nil { |
| 925 | return err |
| 926 | } |
| 927 | |
| 928 | b := bytes.NewReader(rels) |
| 929 | var rela Rela64 |
| 930 | |
| 931 | for b.Len() > 0 { |
| 932 | binary.Read(b, f.ByteOrder, &rela) |
| 933 | var symNo uint64 |
| 934 | var t R_MIPS |
| 935 | if f.ByteOrder == binary.BigEndian { |
| 936 | symNo = rela.Info >> 32 |
| 937 | t = R_MIPS(rela.Info & 0xff) |
| 938 | } else { |
| 939 | symNo = rela.Info & 0xffffffff |
| 940 | t = R_MIPS(rela.Info >> 56) |
| 941 | } |
| 942 | |
| 943 | if symNo == 0 || symNo > uint64(len(symbols)) { |
| 944 | continue |
| 945 | } |
| 946 | sym := &symbols[symNo-1] |
| 947 | if SymType(sym.Info&0xf) != STT_SECTION { |
| 948 | // We don't handle non-section relocations for now. |
| 949 | continue |
| 950 | } |
| 951 | |
| 952 | switch t { |
| 953 | case R_MIPS_64: |
| 954 | if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { |
| 955 | continue |
| 956 | } |
| 957 | f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend)) |
| 958 | case R_MIPS_32: |
| 959 | if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { |
| 960 | continue |
| 961 | } |
| 962 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)) |
| 963 | } |
| 964 | } |
| 965 | |
| 966 | return nil |
| 967 | } |
| 968 | |
| 969 | func (f *File) applyRelocationss390x(dst []byte, rels []byte) error { |
| 970 | // 24 is the size of Rela64. |
| 971 | if len(rels)%24 != 0 { |
| 972 | return errors.New("length of relocation section is not a multiple of 24") |
| 973 | } |
| 974 | |
| 975 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 976 | if err != nil { |
| 977 | return err |
| 978 | } |
| 979 | |
| 980 | b := bytes.NewReader(rels) |
| 981 | var rela Rela64 |
| 982 | |
| 983 | for b.Len() > 0 { |
| 984 | binary.Read(b, f.ByteOrder, &rela) |
| 985 | symNo := rela.Info >> 32 |
| 986 | t := R_390(rela.Info & 0xffff) |
| 987 | |
| 988 | if symNo == 0 || symNo > uint64(len(symbols)) { |
| 989 | continue |
| 990 | } |
| 991 | sym := &symbols[symNo-1] |
| 992 | switch SymType(sym.Info & 0xf) { |
| 993 | case STT_SECTION, STT_NOTYPE: |
| 994 | break |
| 995 | default: |
| 996 | continue |
| 997 | } |
| 998 | |
| 999 | switch t { |
| 1000 | case R_390_64: |
| 1001 | if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { |
| 1002 | continue |
| 1003 | } |
| 1004 | val := sym.Value + uint64(rela.Addend) |
| 1005 | f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val) |
| 1006 | case R_390_32: |
| 1007 | if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { |
| 1008 | continue |
| 1009 | } |
| 1010 | val := uint32(sym.Value) + uint32(rela.Addend) |
| 1011 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val) |
| 1012 | } |
| 1013 | } |
| 1014 | |
| 1015 | return nil |
| 1016 | } |
| 1017 | |
Dan Willemsen | ebae302 | 2017-01-13 23:01:08 -0800 | [diff] [blame] | 1018 | func (f *File) applyRelocationsSPARC64(dst []byte, rels []byte) error { |
| 1019 | // 24 is the size of Rela64. |
| 1020 | if len(rels)%24 != 0 { |
| 1021 | return errors.New("length of relocation section is not a multiple of 24") |
| 1022 | } |
| 1023 | |
| 1024 | symbols, _, err := f.getSymbols(SHT_SYMTAB) |
| 1025 | if err != nil { |
| 1026 | return err |
| 1027 | } |
| 1028 | |
| 1029 | b := bytes.NewReader(rels) |
| 1030 | var rela Rela64 |
| 1031 | |
| 1032 | for b.Len() > 0 { |
| 1033 | binary.Read(b, f.ByteOrder, &rela) |
| 1034 | symNo := rela.Info >> 32 |
| 1035 | t := R_SPARC(rela.Info & 0xff) |
| 1036 | |
| 1037 | if symNo == 0 || symNo > uint64(len(symbols)) { |
| 1038 | continue |
| 1039 | } |
| 1040 | sym := &symbols[symNo-1] |
| 1041 | if SymType(sym.Info&0xf) != STT_SECTION { |
| 1042 | // We don't handle non-section relocations for now. |
| 1043 | continue |
| 1044 | } |
| 1045 | |
| 1046 | switch t { |
| 1047 | case R_SPARC_64, R_SPARC_UA64: |
| 1048 | if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { |
| 1049 | continue |
| 1050 | } |
| 1051 | f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend)) |
| 1052 | case R_SPARC_32, R_SPARC_UA32: |
| 1053 | if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { |
| 1054 | continue |
| 1055 | } |
| 1056 | f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend)) |
| 1057 | } |
| 1058 | } |
| 1059 | |
| 1060 | return nil |
| 1061 | } |
| 1062 | |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1063 | func (f *File) DWARF() (*dwarf.Data, error) { |
| 1064 | // sectionData gets the data for s, checks its size, and |
| 1065 | // applies any applicable relations. |
| 1066 | sectionData := func(i int, s *Section) ([]byte, error) { |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1067 | b, err := s.Data() |
| 1068 | if err != nil && uint64(len(b)) < s.Size { |
| 1069 | return nil, err |
| 1070 | } |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1071 | |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1072 | if len(b) >= 12 && string(b[:4]) == "ZLIB" { |
| 1073 | dlen := binary.BigEndian.Uint64(b[4:12]) |
| 1074 | dbuf := make([]byte, dlen) |
| 1075 | r, err := zlib.NewReader(bytes.NewBuffer(b[12:])) |
| 1076 | if err != nil { |
| 1077 | return nil, err |
| 1078 | } |
| 1079 | if _, err := io.ReadFull(r, dbuf); err != nil { |
| 1080 | return nil, err |
| 1081 | } |
| 1082 | if err := r.Close(); err != nil { |
| 1083 | return nil, err |
| 1084 | } |
| 1085 | b = dbuf |
| 1086 | } |
| 1087 | |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1088 | for _, r := range f.Sections { |
| 1089 | if r.Type != SHT_RELA && r.Type != SHT_REL { |
| 1090 | continue |
| 1091 | } |
| 1092 | if int(r.Info) != i { |
| 1093 | continue |
| 1094 | } |
| 1095 | rd, err := r.Data() |
| 1096 | if err != nil { |
| 1097 | return nil, err |
| 1098 | } |
| 1099 | err = f.applyRelocations(b, rd) |
| 1100 | if err != nil { |
| 1101 | return nil, err |
| 1102 | } |
| 1103 | } |
| 1104 | return b, nil |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1105 | } |
| 1106 | |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1107 | // There are many other DWARF sections, but these |
| 1108 | // are the ones the debug/dwarf package uses. |
| 1109 | // Don't bother loading others. |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1110 | var dat = map[string][]byte{"abbrev": nil, "info": nil, "str": nil, "line": nil, "ranges": nil} |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1111 | for i, s := range f.Sections { |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1112 | suffix := "" |
| 1113 | switch { |
| 1114 | case strings.HasPrefix(s.Name, ".debug_"): |
| 1115 | suffix = s.Name[7:] |
| 1116 | case strings.HasPrefix(s.Name, ".zdebug_"): |
| 1117 | suffix = s.Name[8:] |
| 1118 | default: |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1119 | continue |
| 1120 | } |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1121 | if _, ok := dat[suffix]; !ok { |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1122 | continue |
| 1123 | } |
| 1124 | b, err := sectionData(i, s) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1125 | if err != nil { |
| 1126 | return nil, err |
| 1127 | } |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1128 | dat[suffix] = b |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1129 | } |
| 1130 | |
Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame] | 1131 | d, err := dwarf.New(dat["abbrev"], nil, nil, dat["info"], dat["line"], nil, dat["ranges"], dat["str"]) |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1132 | if err != nil { |
| 1133 | return nil, err |
| 1134 | } |
| 1135 | |
| 1136 | // Look for DWARF4 .debug_types sections. |
| 1137 | for i, s := range f.Sections { |
| 1138 | if s.Name == ".debug_types" { |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 1139 | b, err := sectionData(i, s) |
| 1140 | if err != nil { |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1141 | return nil, err |
| 1142 | } |
| 1143 | |
Brent Austin | ba3052e | 2015-04-21 16:08:23 -0700 | [diff] [blame] | 1144 | err = d.AddTypes(fmt.Sprintf("types-%d", i), b) |
| 1145 | if err != nil { |
| 1146 | return nil, err |
| 1147 | } |
| 1148 | } |
| 1149 | } |
| 1150 | |
| 1151 | return d, nil |
| 1152 | } |
| 1153 | |
| 1154 | // Symbols returns the symbol table for f. The symbols will be listed in the order |
| 1155 | // they appear in f. |
| 1156 | // |
| 1157 | // For compatibility with Go 1.0, Symbols omits the null symbol at index 0. |
| 1158 | // After retrieving the symbols as symtab, an externally supplied index x |
| 1159 | // corresponds to symtab[x-1], not symtab[x]. |
| 1160 | func (f *File) Symbols() ([]Symbol, error) { |
| 1161 | sym, _, err := f.getSymbols(SHT_SYMTAB) |
| 1162 | return sym, err |
| 1163 | } |
| 1164 | |
| 1165 | // DynamicSymbols returns the dynamic symbol table for f. The symbols |
| 1166 | // will be listed in the order they appear in f. |
| 1167 | // |
| 1168 | // For compatibility with Symbols, DynamicSymbols omits the null symbol at index 0. |
| 1169 | // After retrieving the symbols as symtab, an externally supplied index x |
| 1170 | // corresponds to symtab[x-1], not symtab[x]. |
| 1171 | func (f *File) DynamicSymbols() ([]Symbol, error) { |
| 1172 | sym, _, err := f.getSymbols(SHT_DYNSYM) |
| 1173 | return sym, err |
| 1174 | } |
| 1175 | |
| 1176 | type ImportedSymbol struct { |
| 1177 | Name string |
| 1178 | Version string |
| 1179 | Library string |
| 1180 | } |
| 1181 | |
| 1182 | // ImportedSymbols returns the names of all symbols |
| 1183 | // referred to by the binary f that are expected to be |
| 1184 | // satisfied by other libraries at dynamic load time. |
| 1185 | // It does not return weak symbols. |
| 1186 | func (f *File) ImportedSymbols() ([]ImportedSymbol, error) { |
| 1187 | sym, str, err := f.getSymbols(SHT_DYNSYM) |
| 1188 | if err != nil { |
| 1189 | return nil, err |
| 1190 | } |
| 1191 | f.gnuVersionInit(str) |
| 1192 | var all []ImportedSymbol |
| 1193 | for i, s := range sym { |
| 1194 | if ST_BIND(s.Info) == STB_GLOBAL && s.Section == SHN_UNDEF { |
| 1195 | all = append(all, ImportedSymbol{Name: s.Name}) |
| 1196 | f.gnuVersion(i, &all[len(all)-1]) |
| 1197 | } |
| 1198 | } |
| 1199 | return all, nil |
| 1200 | } |
| 1201 | |
| 1202 | type verneed struct { |
| 1203 | File string |
| 1204 | Name string |
| 1205 | } |
| 1206 | |
| 1207 | // gnuVersionInit parses the GNU version tables |
| 1208 | // for use by calls to gnuVersion. |
| 1209 | func (f *File) gnuVersionInit(str []byte) { |
| 1210 | // Accumulate verneed information. |
| 1211 | vn := f.SectionByType(SHT_GNU_VERNEED) |
| 1212 | if vn == nil { |
| 1213 | return |
| 1214 | } |
| 1215 | d, _ := vn.Data() |
| 1216 | |
| 1217 | var need []verneed |
| 1218 | i := 0 |
| 1219 | for { |
| 1220 | if i+16 > len(d) { |
| 1221 | break |
| 1222 | } |
| 1223 | vers := f.ByteOrder.Uint16(d[i : i+2]) |
| 1224 | if vers != 1 { |
| 1225 | break |
| 1226 | } |
| 1227 | cnt := f.ByteOrder.Uint16(d[i+2 : i+4]) |
| 1228 | fileoff := f.ByteOrder.Uint32(d[i+4 : i+8]) |
| 1229 | aux := f.ByteOrder.Uint32(d[i+8 : i+12]) |
| 1230 | next := f.ByteOrder.Uint32(d[i+12 : i+16]) |
| 1231 | file, _ := getString(str, int(fileoff)) |
| 1232 | |
| 1233 | var name string |
| 1234 | j := i + int(aux) |
| 1235 | for c := 0; c < int(cnt); c++ { |
| 1236 | if j+16 > len(d) { |
| 1237 | break |
| 1238 | } |
| 1239 | // hash := f.ByteOrder.Uint32(d[j:j+4]) |
| 1240 | // flags := f.ByteOrder.Uint16(d[j+4:j+6]) |
| 1241 | other := f.ByteOrder.Uint16(d[j+6 : j+8]) |
| 1242 | nameoff := f.ByteOrder.Uint32(d[j+8 : j+12]) |
| 1243 | next := f.ByteOrder.Uint32(d[j+12 : j+16]) |
| 1244 | name, _ = getString(str, int(nameoff)) |
| 1245 | ndx := int(other) |
| 1246 | if ndx >= len(need) { |
| 1247 | a := make([]verneed, 2*(ndx+1)) |
| 1248 | copy(a, need) |
| 1249 | need = a |
| 1250 | } |
| 1251 | |
| 1252 | need[ndx] = verneed{file, name} |
| 1253 | if next == 0 { |
| 1254 | break |
| 1255 | } |
| 1256 | j += int(next) |
| 1257 | } |
| 1258 | |
| 1259 | if next == 0 { |
| 1260 | break |
| 1261 | } |
| 1262 | i += int(next) |
| 1263 | } |
| 1264 | |
| 1265 | // Versym parallels symbol table, indexing into verneed. |
| 1266 | vs := f.SectionByType(SHT_GNU_VERSYM) |
| 1267 | if vs == nil { |
| 1268 | return |
| 1269 | } |
| 1270 | d, _ = vs.Data() |
| 1271 | |
| 1272 | f.gnuNeed = need |
| 1273 | f.gnuVersym = d |
| 1274 | } |
| 1275 | |
| 1276 | // gnuVersion adds Library and Version information to sym, |
| 1277 | // which came from offset i of the symbol table. |
| 1278 | func (f *File) gnuVersion(i int, sym *ImportedSymbol) { |
| 1279 | // Each entry is two bytes. |
| 1280 | i = (i + 1) * 2 |
| 1281 | if i >= len(f.gnuVersym) { |
| 1282 | return |
| 1283 | } |
| 1284 | j := int(f.ByteOrder.Uint16(f.gnuVersym[i:])) |
| 1285 | if j < 2 || j >= len(f.gnuNeed) { |
| 1286 | return |
| 1287 | } |
| 1288 | n := &f.gnuNeed[j] |
| 1289 | sym.Library = n.File |
| 1290 | sym.Version = n.Name |
| 1291 | } |
| 1292 | |
| 1293 | // ImportedLibraries returns the names of all libraries |
| 1294 | // referred to by the binary f that are expected to be |
| 1295 | // linked with the binary at dynamic link time. |
| 1296 | func (f *File) ImportedLibraries() ([]string, error) { |
| 1297 | return f.DynString(DT_NEEDED) |
| 1298 | } |
| 1299 | |
| 1300 | // DynString returns the strings listed for the given tag in the file's dynamic |
| 1301 | // section. |
| 1302 | // |
| 1303 | // The tag must be one that takes string values: DT_NEEDED, DT_SONAME, DT_RPATH, or |
| 1304 | // DT_RUNPATH. |
| 1305 | func (f *File) DynString(tag DynTag) ([]string, error) { |
| 1306 | switch tag { |
| 1307 | case DT_NEEDED, DT_SONAME, DT_RPATH, DT_RUNPATH: |
| 1308 | default: |
| 1309 | return nil, fmt.Errorf("non-string-valued tag %v", tag) |
| 1310 | } |
| 1311 | ds := f.SectionByType(SHT_DYNAMIC) |
| 1312 | if ds == nil { |
| 1313 | // not dynamic, so no libraries |
| 1314 | return nil, nil |
| 1315 | } |
| 1316 | d, err := ds.Data() |
| 1317 | if err != nil { |
| 1318 | return nil, err |
| 1319 | } |
| 1320 | str, err := f.stringTable(ds.Link) |
| 1321 | if err != nil { |
| 1322 | return nil, err |
| 1323 | } |
| 1324 | var all []string |
| 1325 | for len(d) > 0 { |
| 1326 | var t DynTag |
| 1327 | var v uint64 |
| 1328 | switch f.Class { |
| 1329 | case ELFCLASS32: |
| 1330 | t = DynTag(f.ByteOrder.Uint32(d[0:4])) |
| 1331 | v = uint64(f.ByteOrder.Uint32(d[4:8])) |
| 1332 | d = d[8:] |
| 1333 | case ELFCLASS64: |
| 1334 | t = DynTag(f.ByteOrder.Uint64(d[0:8])) |
| 1335 | v = f.ByteOrder.Uint64(d[8:16]) |
| 1336 | d = d[16:] |
| 1337 | } |
| 1338 | if t == tag { |
| 1339 | s, ok := getString(str, int(v)) |
| 1340 | if ok { |
| 1341 | all = append(all, s) |
| 1342 | } |
| 1343 | } |
| 1344 | } |
| 1345 | return all, nil |
| 1346 | } |