Matteo Scandolo | a428586 | 2020-12-01 18:10:10 -0800 | [diff] [blame^] | 1 | // Copyright 2011 The Go Authors. All rights reserved. |
| 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 windows |
| 6 | |
| 7 | import ( |
| 8 | "sync" |
| 9 | "sync/atomic" |
| 10 | "syscall" |
| 11 | "unsafe" |
| 12 | ) |
| 13 | |
| 14 | // We need to use LoadLibrary and GetProcAddress from the Go runtime, because |
| 15 | // the these symbols are loaded by the system linker and are required to |
| 16 | // dynamically load additional symbols. Note that in the Go runtime, these |
| 17 | // return syscall.Handle and syscall.Errno, but these are the same, in fact, |
| 18 | // as windows.Handle and windows.Errno, and we intend to keep these the same. |
| 19 | |
| 20 | //go:linkname syscall_loadlibrary syscall.loadlibrary |
| 21 | func syscall_loadlibrary(filename *uint16) (handle Handle, err Errno) |
| 22 | |
| 23 | //go:linkname syscall_getprocaddress syscall.getprocaddress |
| 24 | func syscall_getprocaddress(handle Handle, procname *uint8) (proc uintptr, err Errno) |
| 25 | |
| 26 | // DLLError describes reasons for DLL load failures. |
| 27 | type DLLError struct { |
| 28 | Err error |
| 29 | ObjName string |
| 30 | Msg string |
| 31 | } |
| 32 | |
| 33 | func (e *DLLError) Error() string { return e.Msg } |
| 34 | |
| 35 | // A DLL implements access to a single DLL. |
| 36 | type DLL struct { |
| 37 | Name string |
| 38 | Handle Handle |
| 39 | } |
| 40 | |
| 41 | // LoadDLL loads DLL file into memory. |
| 42 | // |
| 43 | // Warning: using LoadDLL without an absolute path name is subject to |
| 44 | // DLL preloading attacks. To safely load a system DLL, use LazyDLL |
| 45 | // with System set to true, or use LoadLibraryEx directly. |
| 46 | func LoadDLL(name string) (dll *DLL, err error) { |
| 47 | namep, err := UTF16PtrFromString(name) |
| 48 | if err != nil { |
| 49 | return nil, err |
| 50 | } |
| 51 | h, e := syscall_loadlibrary(namep) |
| 52 | if e != 0 { |
| 53 | return nil, &DLLError{ |
| 54 | Err: e, |
| 55 | ObjName: name, |
| 56 | Msg: "Failed to load " + name + ": " + e.Error(), |
| 57 | } |
| 58 | } |
| 59 | d := &DLL{ |
| 60 | Name: name, |
| 61 | Handle: h, |
| 62 | } |
| 63 | return d, nil |
| 64 | } |
| 65 | |
| 66 | // MustLoadDLL is like LoadDLL but panics if load operation failes. |
| 67 | func MustLoadDLL(name string) *DLL { |
| 68 | d, e := LoadDLL(name) |
| 69 | if e != nil { |
| 70 | panic(e) |
| 71 | } |
| 72 | return d |
| 73 | } |
| 74 | |
| 75 | // FindProc searches DLL d for procedure named name and returns *Proc |
| 76 | // if found. It returns an error if search fails. |
| 77 | func (d *DLL) FindProc(name string) (proc *Proc, err error) { |
| 78 | namep, err := BytePtrFromString(name) |
| 79 | if err != nil { |
| 80 | return nil, err |
| 81 | } |
| 82 | a, e := syscall_getprocaddress(d.Handle, namep) |
| 83 | if e != 0 { |
| 84 | return nil, &DLLError{ |
| 85 | Err: e, |
| 86 | ObjName: name, |
| 87 | Msg: "Failed to find " + name + " procedure in " + d.Name + ": " + e.Error(), |
| 88 | } |
| 89 | } |
| 90 | p := &Proc{ |
| 91 | Dll: d, |
| 92 | Name: name, |
| 93 | addr: a, |
| 94 | } |
| 95 | return p, nil |
| 96 | } |
| 97 | |
| 98 | // MustFindProc is like FindProc but panics if search fails. |
| 99 | func (d *DLL) MustFindProc(name string) *Proc { |
| 100 | p, e := d.FindProc(name) |
| 101 | if e != nil { |
| 102 | panic(e) |
| 103 | } |
| 104 | return p |
| 105 | } |
| 106 | |
| 107 | // FindProcByOrdinal searches DLL d for procedure by ordinal and returns *Proc |
| 108 | // if found. It returns an error if search fails. |
| 109 | func (d *DLL) FindProcByOrdinal(ordinal uintptr) (proc *Proc, err error) { |
| 110 | a, e := GetProcAddressByOrdinal(d.Handle, ordinal) |
| 111 | name := "#" + itoa(int(ordinal)) |
| 112 | if e != nil { |
| 113 | return nil, &DLLError{ |
| 114 | Err: e, |
| 115 | ObjName: name, |
| 116 | Msg: "Failed to find " + name + " procedure in " + d.Name + ": " + e.Error(), |
| 117 | } |
| 118 | } |
| 119 | p := &Proc{ |
| 120 | Dll: d, |
| 121 | Name: name, |
| 122 | addr: a, |
| 123 | } |
| 124 | return p, nil |
| 125 | } |
| 126 | |
| 127 | // MustFindProcByOrdinal is like FindProcByOrdinal but panics if search fails. |
| 128 | func (d *DLL) MustFindProcByOrdinal(ordinal uintptr) *Proc { |
| 129 | p, e := d.FindProcByOrdinal(ordinal) |
| 130 | if e != nil { |
| 131 | panic(e) |
| 132 | } |
| 133 | return p |
| 134 | } |
| 135 | |
| 136 | // Release unloads DLL d from memory. |
| 137 | func (d *DLL) Release() (err error) { |
| 138 | return FreeLibrary(d.Handle) |
| 139 | } |
| 140 | |
| 141 | // A Proc implements access to a procedure inside a DLL. |
| 142 | type Proc struct { |
| 143 | Dll *DLL |
| 144 | Name string |
| 145 | addr uintptr |
| 146 | } |
| 147 | |
| 148 | // Addr returns the address of the procedure represented by p. |
| 149 | // The return value can be passed to Syscall to run the procedure. |
| 150 | func (p *Proc) Addr() uintptr { |
| 151 | return p.addr |
| 152 | } |
| 153 | |
| 154 | //go:uintptrescapes |
| 155 | |
| 156 | // Call executes procedure p with arguments a. It will panic, if more than 15 arguments |
| 157 | // are supplied. |
| 158 | // |
| 159 | // The returned error is always non-nil, constructed from the result of GetLastError. |
| 160 | // Callers must inspect the primary return value to decide whether an error occurred |
| 161 | // (according to the semantics of the specific function being called) before consulting |
| 162 | // the error. The error will be guaranteed to contain windows.Errno. |
| 163 | func (p *Proc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) { |
| 164 | switch len(a) { |
| 165 | case 0: |
| 166 | return syscall.Syscall(p.Addr(), uintptr(len(a)), 0, 0, 0) |
| 167 | case 1: |
| 168 | return syscall.Syscall(p.Addr(), uintptr(len(a)), a[0], 0, 0) |
| 169 | case 2: |
| 170 | return syscall.Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], 0) |
| 171 | case 3: |
| 172 | return syscall.Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], a[2]) |
| 173 | case 4: |
| 174 | return syscall.Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], 0, 0) |
| 175 | case 5: |
| 176 | return syscall.Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], 0) |
| 177 | case 6: |
| 178 | return syscall.Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5]) |
| 179 | case 7: |
| 180 | return syscall.Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], 0, 0) |
| 181 | case 8: |
| 182 | return syscall.Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], 0) |
| 183 | case 9: |
| 184 | return syscall.Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8]) |
| 185 | case 10: |
| 186 | return syscall.Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], 0, 0) |
| 187 | case 11: |
| 188 | return syscall.Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], 0) |
| 189 | case 12: |
| 190 | return syscall.Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11]) |
| 191 | case 13: |
| 192 | return syscall.Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], 0, 0) |
| 193 | case 14: |
| 194 | return syscall.Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], 0) |
| 195 | case 15: |
| 196 | return syscall.Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14]) |
| 197 | default: |
| 198 | panic("Call " + p.Name + " with too many arguments " + itoa(len(a)) + ".") |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | // A LazyDLL implements access to a single DLL. |
| 203 | // It will delay the load of the DLL until the first |
| 204 | // call to its Handle method or to one of its |
| 205 | // LazyProc's Addr method. |
| 206 | type LazyDLL struct { |
| 207 | Name string |
| 208 | |
| 209 | // System determines whether the DLL must be loaded from the |
| 210 | // Windows System directory, bypassing the normal DLL search |
| 211 | // path. |
| 212 | System bool |
| 213 | |
| 214 | mu sync.Mutex |
| 215 | dll *DLL // non nil once DLL is loaded |
| 216 | } |
| 217 | |
| 218 | // Load loads DLL file d.Name into memory. It returns an error if fails. |
| 219 | // Load will not try to load DLL, if it is already loaded into memory. |
| 220 | func (d *LazyDLL) Load() error { |
| 221 | // Non-racy version of: |
| 222 | // if d.dll != nil { |
| 223 | if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.dll))) != nil { |
| 224 | return nil |
| 225 | } |
| 226 | d.mu.Lock() |
| 227 | defer d.mu.Unlock() |
| 228 | if d.dll != nil { |
| 229 | return nil |
| 230 | } |
| 231 | |
| 232 | // kernel32.dll is special, since it's where LoadLibraryEx comes from. |
| 233 | // The kernel already special-cases its name, so it's always |
| 234 | // loaded from system32. |
| 235 | var dll *DLL |
| 236 | var err error |
| 237 | if d.Name == "kernel32.dll" { |
| 238 | dll, err = LoadDLL(d.Name) |
| 239 | } else { |
| 240 | dll, err = loadLibraryEx(d.Name, d.System) |
| 241 | } |
| 242 | if err != nil { |
| 243 | return err |
| 244 | } |
| 245 | |
| 246 | // Non-racy version of: |
| 247 | // d.dll = dll |
| 248 | atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.dll)), unsafe.Pointer(dll)) |
| 249 | return nil |
| 250 | } |
| 251 | |
| 252 | // mustLoad is like Load but panics if search fails. |
| 253 | func (d *LazyDLL) mustLoad() { |
| 254 | e := d.Load() |
| 255 | if e != nil { |
| 256 | panic(e) |
| 257 | } |
| 258 | } |
| 259 | |
| 260 | // Handle returns d's module handle. |
| 261 | func (d *LazyDLL) Handle() uintptr { |
| 262 | d.mustLoad() |
| 263 | return uintptr(d.dll.Handle) |
| 264 | } |
| 265 | |
| 266 | // NewProc returns a LazyProc for accessing the named procedure in the DLL d. |
| 267 | func (d *LazyDLL) NewProc(name string) *LazyProc { |
| 268 | return &LazyProc{l: d, Name: name} |
| 269 | } |
| 270 | |
| 271 | // NewLazyDLL creates new LazyDLL associated with DLL file. |
| 272 | func NewLazyDLL(name string) *LazyDLL { |
| 273 | return &LazyDLL{Name: name} |
| 274 | } |
| 275 | |
| 276 | // NewLazySystemDLL is like NewLazyDLL, but will only |
| 277 | // search Windows System directory for the DLL if name is |
| 278 | // a base name (like "advapi32.dll"). |
| 279 | func NewLazySystemDLL(name string) *LazyDLL { |
| 280 | return &LazyDLL{Name: name, System: true} |
| 281 | } |
| 282 | |
| 283 | // A LazyProc implements access to a procedure inside a LazyDLL. |
| 284 | // It delays the lookup until the Addr method is called. |
| 285 | type LazyProc struct { |
| 286 | Name string |
| 287 | |
| 288 | mu sync.Mutex |
| 289 | l *LazyDLL |
| 290 | proc *Proc |
| 291 | } |
| 292 | |
| 293 | // Find searches DLL for procedure named p.Name. It returns |
| 294 | // an error if search fails. Find will not search procedure, |
| 295 | // if it is already found and loaded into memory. |
| 296 | func (p *LazyProc) Find() error { |
| 297 | // Non-racy version of: |
| 298 | // if p.proc == nil { |
| 299 | if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&p.proc))) == nil { |
| 300 | p.mu.Lock() |
| 301 | defer p.mu.Unlock() |
| 302 | if p.proc == nil { |
| 303 | e := p.l.Load() |
| 304 | if e != nil { |
| 305 | return e |
| 306 | } |
| 307 | proc, e := p.l.dll.FindProc(p.Name) |
| 308 | if e != nil { |
| 309 | return e |
| 310 | } |
| 311 | // Non-racy version of: |
| 312 | // p.proc = proc |
| 313 | atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.proc)), unsafe.Pointer(proc)) |
| 314 | } |
| 315 | } |
| 316 | return nil |
| 317 | } |
| 318 | |
| 319 | // mustFind is like Find but panics if search fails. |
| 320 | func (p *LazyProc) mustFind() { |
| 321 | e := p.Find() |
| 322 | if e != nil { |
| 323 | panic(e) |
| 324 | } |
| 325 | } |
| 326 | |
| 327 | // Addr returns the address of the procedure represented by p. |
| 328 | // The return value can be passed to Syscall to run the procedure. |
| 329 | // It will panic if the procedure cannot be found. |
| 330 | func (p *LazyProc) Addr() uintptr { |
| 331 | p.mustFind() |
| 332 | return p.proc.Addr() |
| 333 | } |
| 334 | |
| 335 | //go:uintptrescapes |
| 336 | |
| 337 | // Call executes procedure p with arguments a. It will panic, if more than 15 arguments |
| 338 | // are supplied. It will also panic if the procedure cannot be found. |
| 339 | // |
| 340 | // The returned error is always non-nil, constructed from the result of GetLastError. |
| 341 | // Callers must inspect the primary return value to decide whether an error occurred |
| 342 | // (according to the semantics of the specific function being called) before consulting |
| 343 | // the error. The error will be guaranteed to contain windows.Errno. |
| 344 | func (p *LazyProc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) { |
| 345 | p.mustFind() |
| 346 | return p.proc.Call(a...) |
| 347 | } |
| 348 | |
| 349 | var canDoSearchSystem32Once struct { |
| 350 | sync.Once |
| 351 | v bool |
| 352 | } |
| 353 | |
| 354 | func initCanDoSearchSystem32() { |
| 355 | // https://msdn.microsoft.com/en-us/library/ms684179(v=vs.85).aspx says: |
| 356 | // "Windows 7, Windows Server 2008 R2, Windows Vista, and Windows |
| 357 | // Server 2008: The LOAD_LIBRARY_SEARCH_* flags are available on |
| 358 | // systems that have KB2533623 installed. To determine whether the |
| 359 | // flags are available, use GetProcAddress to get the address of the |
| 360 | // AddDllDirectory, RemoveDllDirectory, or SetDefaultDllDirectories |
| 361 | // function. If GetProcAddress succeeds, the LOAD_LIBRARY_SEARCH_* |
| 362 | // flags can be used with LoadLibraryEx." |
| 363 | canDoSearchSystem32Once.v = (modkernel32.NewProc("AddDllDirectory").Find() == nil) |
| 364 | } |
| 365 | |
| 366 | func canDoSearchSystem32() bool { |
| 367 | canDoSearchSystem32Once.Do(initCanDoSearchSystem32) |
| 368 | return canDoSearchSystem32Once.v |
| 369 | } |
| 370 | |
| 371 | func isBaseName(name string) bool { |
| 372 | for _, c := range name { |
| 373 | if c == ':' || c == '/' || c == '\\' { |
| 374 | return false |
| 375 | } |
| 376 | } |
| 377 | return true |
| 378 | } |
| 379 | |
| 380 | // loadLibraryEx wraps the Windows LoadLibraryEx function. |
| 381 | // |
| 382 | // See https://msdn.microsoft.com/en-us/library/windows/desktop/ms684179(v=vs.85).aspx |
| 383 | // |
| 384 | // If name is not an absolute path, LoadLibraryEx searches for the DLL |
| 385 | // in a variety of automatic locations unless constrained by flags. |
| 386 | // See: https://msdn.microsoft.com/en-us/library/ff919712%28VS.85%29.aspx |
| 387 | func loadLibraryEx(name string, system bool) (*DLL, error) { |
| 388 | loadDLL := name |
| 389 | var flags uintptr |
| 390 | if system { |
| 391 | if canDoSearchSystem32() { |
| 392 | const LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800 |
| 393 | flags = LOAD_LIBRARY_SEARCH_SYSTEM32 |
| 394 | } else if isBaseName(name) { |
| 395 | // WindowsXP or unpatched Windows machine |
| 396 | // trying to load "foo.dll" out of the system |
| 397 | // folder, but LoadLibraryEx doesn't support |
| 398 | // that yet on their system, so emulate it. |
| 399 | systemdir, err := GetSystemDirectory() |
| 400 | if err != nil { |
| 401 | return nil, err |
| 402 | } |
| 403 | loadDLL = systemdir + "\\" + name |
| 404 | } |
| 405 | } |
| 406 | h, err := LoadLibraryEx(loadDLL, 0, flags) |
| 407 | if err != nil { |
| 408 | return nil, err |
| 409 | } |
| 410 | return &DLL{Name: name, Handle: h}, nil |
| 411 | } |
| 412 | |
| 413 | type errString string |
| 414 | |
| 415 | func (s errString) Error() string { return string(s) } |