| 1 | /* Internal interfaces for the Windows code |
| 2 | Copyright (C) 1995-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 3 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include "gdbsupport/common-defs.h" |
| 20 | #include "nat/windows-nat.h" |
| 21 | #include "gdbsupport/common-debug.h" |
| 22 | |
| 23 | namespace windows_nat |
| 24 | { |
| 25 | |
| 26 | HANDLE current_process_handle; |
| 27 | DWORD current_process_id; |
| 28 | DWORD main_thread_id; |
| 29 | enum gdb_signal last_sig = GDB_SIGNAL_0; |
| 30 | DEBUG_EVENT current_event; |
| 31 | |
| 32 | /* The most recent event from WaitForDebugEvent. Unlike |
| 33 | current_event, this is guaranteed never to come from a pending |
| 34 | stop. This is important because only data from the most recent |
| 35 | event from WaitForDebugEvent can be used when calling |
| 36 | ContinueDebugEvent. */ |
| 37 | static DEBUG_EVENT last_wait_event; |
| 38 | |
| 39 | DWORD desired_stop_thread_id = -1; |
| 40 | std::vector<pending_stop> pending_stops; |
| 41 | EXCEPTION_RECORD siginfo_er; |
| 42 | |
| 43 | #ifdef __x86_64__ |
| 44 | bool ignore_first_breakpoint = false; |
| 45 | #endif |
| 46 | |
| 47 | /* Note that 'debug_events' must be locally defined in the relevant |
| 48 | functions. */ |
| 49 | #define DEBUG_EVENTS(x) if (debug_events) debug_printf x |
| 50 | |
| 51 | windows_thread_info::~windows_thread_info () |
| 52 | { |
| 53 | } |
| 54 | |
| 55 | void |
| 56 | windows_thread_info::suspend () |
| 57 | { |
| 58 | if (suspended != 0) |
| 59 | return; |
| 60 | |
| 61 | if (SuspendThread (h) == (DWORD) -1) |
| 62 | { |
| 63 | DWORD err = GetLastError (); |
| 64 | |
| 65 | /* We get Access Denied (5) when trying to suspend |
| 66 | threads that Windows started on behalf of the |
| 67 | debuggee, usually when those threads are just |
| 68 | about to exit. |
| 69 | We can get Invalid Handle (6) if the main thread |
| 70 | has exited. */ |
| 71 | if (err != ERROR_INVALID_HANDLE && err != ERROR_ACCESS_DENIED) |
| 72 | warning (_("SuspendThread (tid=0x%x) failed. (winerr %u)"), |
| 73 | (unsigned) tid, (unsigned) err); |
| 74 | suspended = -1; |
| 75 | } |
| 76 | else |
| 77 | suspended = 1; |
| 78 | } |
| 79 | |
| 80 | void |
| 81 | windows_thread_info::resume () |
| 82 | { |
| 83 | if (suspended > 0) |
| 84 | { |
| 85 | stopped_at_software_breakpoint = false; |
| 86 | |
| 87 | if (ResumeThread (h) == (DWORD) -1) |
| 88 | { |
| 89 | DWORD err = GetLastError (); |
| 90 | warning (_("warning: ResumeThread (tid=0x%x) failed. (winerr %u)"), |
| 91 | (unsigned) tid, (unsigned) err); |
| 92 | } |
| 93 | } |
| 94 | suspended = 0; |
| 95 | } |
| 96 | |
| 97 | const char * |
| 98 | get_image_name (HANDLE h, void *address, int unicode) |
| 99 | { |
| 100 | #ifdef __CYGWIN__ |
| 101 | static char buf[MAX_PATH]; |
| 102 | #else |
| 103 | static char buf[(2 * MAX_PATH) + 1]; |
| 104 | #endif |
| 105 | DWORD size = unicode ? sizeof (WCHAR) : sizeof (char); |
| 106 | char *address_ptr; |
| 107 | int len = 0; |
| 108 | char b[2]; |
| 109 | SIZE_T done; |
| 110 | |
| 111 | /* Attempt to read the name of the dll that was detected. |
| 112 | This is documented to work only when actively debugging |
| 113 | a program. It will not work for attached processes. */ |
| 114 | if (address == NULL) |
| 115 | return NULL; |
| 116 | |
| 117 | #ifdef _WIN32_WCE |
| 118 | /* Windows CE reports the address of the image name, |
| 119 | instead of an address of a pointer into the image name. */ |
| 120 | address_ptr = address; |
| 121 | #else |
| 122 | /* See if we could read the address of a string, and that the |
| 123 | address isn't null. */ |
| 124 | if (!ReadProcessMemory (h, address, &address_ptr, |
| 125 | sizeof (address_ptr), &done) |
| 126 | || done != sizeof (address_ptr) |
| 127 | || !address_ptr) |
| 128 | return NULL; |
| 129 | #endif |
| 130 | |
| 131 | /* Find the length of the string. */ |
| 132 | while (ReadProcessMemory (h, address_ptr + len++ * size, &b, size, &done) |
| 133 | && (b[0] != 0 || b[size - 1] != 0) && done == size) |
| 134 | continue; |
| 135 | |
| 136 | if (!unicode) |
| 137 | ReadProcessMemory (h, address_ptr, buf, len, &done); |
| 138 | else |
| 139 | { |
| 140 | WCHAR *unicode_address = (WCHAR *) alloca (len * sizeof (WCHAR)); |
| 141 | ReadProcessMemory (h, address_ptr, unicode_address, len * sizeof (WCHAR), |
| 142 | &done); |
| 143 | #ifdef __CYGWIN__ |
| 144 | wcstombs (buf, unicode_address, MAX_PATH); |
| 145 | #else |
| 146 | WideCharToMultiByte (CP_ACP, 0, unicode_address, len, buf, sizeof buf, |
| 147 | 0, 0); |
| 148 | #endif |
| 149 | } |
| 150 | |
| 151 | return buf; |
| 152 | } |
| 153 | |
| 154 | /* The exception thrown by a program to tell the debugger the name of |
| 155 | a thread. The exception record contains an ID of a thread and a |
| 156 | name to give it. This exception has no documented name, but MSDN |
| 157 | dubs it "MS_VC_EXCEPTION" in one code example. */ |
| 158 | #define MS_VC_EXCEPTION 0x406d1388 |
| 159 | |
| 160 | handle_exception_result |
| 161 | handle_exception (struct target_waitstatus *ourstatus, bool debug_exceptions) |
| 162 | { |
| 163 | #define DEBUG_EXCEPTION_SIMPLE(x) if (debug_exceptions) \ |
| 164 | debug_printf ("gdb: Target exception %s at %s\n", x, \ |
| 165 | host_address_to_string (\ |
| 166 | current_event.u.Exception.ExceptionRecord.ExceptionAddress)) |
| 167 | |
| 168 | EXCEPTION_RECORD *rec = ¤t_event.u.Exception.ExceptionRecord; |
| 169 | DWORD code = rec->ExceptionCode; |
| 170 | handle_exception_result result = HANDLE_EXCEPTION_HANDLED; |
| 171 | |
| 172 | memcpy (&siginfo_er, rec, sizeof siginfo_er); |
| 173 | |
| 174 | ourstatus->kind = TARGET_WAITKIND_STOPPED; |
| 175 | |
| 176 | /* Record the context of the current thread. */ |
| 177 | thread_rec (ptid_t (current_event.dwProcessId, current_event.dwThreadId, 0), |
| 178 | DONT_SUSPEND); |
| 179 | |
| 180 | switch (code) |
| 181 | { |
| 182 | case EXCEPTION_ACCESS_VIOLATION: |
| 183 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ACCESS_VIOLATION"); |
| 184 | ourstatus->value.sig = GDB_SIGNAL_SEGV; |
| 185 | if (handle_access_violation (rec)) |
| 186 | return HANDLE_EXCEPTION_UNHANDLED; |
| 187 | break; |
| 188 | case STATUS_STACK_OVERFLOW: |
| 189 | DEBUG_EXCEPTION_SIMPLE ("STATUS_STACK_OVERFLOW"); |
| 190 | ourstatus->value.sig = GDB_SIGNAL_SEGV; |
| 191 | break; |
| 192 | case STATUS_FLOAT_DENORMAL_OPERAND: |
| 193 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DENORMAL_OPERAND"); |
| 194 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 195 | break; |
| 196 | case EXCEPTION_ARRAY_BOUNDS_EXCEEDED: |
| 197 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ARRAY_BOUNDS_EXCEEDED"); |
| 198 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 199 | break; |
| 200 | case STATUS_FLOAT_INEXACT_RESULT: |
| 201 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INEXACT_RESULT"); |
| 202 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 203 | break; |
| 204 | case STATUS_FLOAT_INVALID_OPERATION: |
| 205 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INVALID_OPERATION"); |
| 206 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 207 | break; |
| 208 | case STATUS_FLOAT_OVERFLOW: |
| 209 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_OVERFLOW"); |
| 210 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 211 | break; |
| 212 | case STATUS_FLOAT_STACK_CHECK: |
| 213 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_STACK_CHECK"); |
| 214 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 215 | break; |
| 216 | case STATUS_FLOAT_UNDERFLOW: |
| 217 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_UNDERFLOW"); |
| 218 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 219 | break; |
| 220 | case STATUS_FLOAT_DIVIDE_BY_ZERO: |
| 221 | DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DIVIDE_BY_ZERO"); |
| 222 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 223 | break; |
| 224 | case STATUS_INTEGER_DIVIDE_BY_ZERO: |
| 225 | DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_DIVIDE_BY_ZERO"); |
| 226 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 227 | break; |
| 228 | case STATUS_INTEGER_OVERFLOW: |
| 229 | DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_OVERFLOW"); |
| 230 | ourstatus->value.sig = GDB_SIGNAL_FPE; |
| 231 | break; |
| 232 | case EXCEPTION_BREAKPOINT: |
| 233 | #ifdef __x86_64__ |
| 234 | if (ignore_first_breakpoint) |
| 235 | { |
| 236 | /* For WOW64 processes, there are always 2 breakpoint exceptions |
| 237 | on startup, first a BREAKPOINT for the 64bit ntdll.dll, |
| 238 | then a WX86_BREAKPOINT for the 32bit ntdll.dll. |
| 239 | Here we only care about the WX86_BREAKPOINT's. */ |
| 240 | ourstatus->kind = TARGET_WAITKIND_SPURIOUS; |
| 241 | ignore_first_breakpoint = false; |
| 242 | } |
| 243 | #endif |
| 244 | /* FALLTHROUGH */ |
| 245 | case STATUS_WX86_BREAKPOINT: |
| 246 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_BREAKPOINT"); |
| 247 | ourstatus->value.sig = GDB_SIGNAL_TRAP; |
| 248 | #ifdef _WIN32_WCE |
| 249 | /* Remove the initial breakpoint. */ |
| 250 | check_breakpoints ((CORE_ADDR) (long) current_event |
| 251 | .u.Exception.ExceptionRecord.ExceptionAddress); |
| 252 | #endif |
| 253 | break; |
| 254 | case DBG_CONTROL_C: |
| 255 | DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_C"); |
| 256 | ourstatus->value.sig = GDB_SIGNAL_INT; |
| 257 | break; |
| 258 | case DBG_CONTROL_BREAK: |
| 259 | DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_BREAK"); |
| 260 | ourstatus->value.sig = GDB_SIGNAL_INT; |
| 261 | break; |
| 262 | case EXCEPTION_SINGLE_STEP: |
| 263 | case STATUS_WX86_SINGLE_STEP: |
| 264 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_SINGLE_STEP"); |
| 265 | ourstatus->value.sig = GDB_SIGNAL_TRAP; |
| 266 | break; |
| 267 | case EXCEPTION_ILLEGAL_INSTRUCTION: |
| 268 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ILLEGAL_INSTRUCTION"); |
| 269 | ourstatus->value.sig = GDB_SIGNAL_ILL; |
| 270 | break; |
| 271 | case EXCEPTION_PRIV_INSTRUCTION: |
| 272 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_PRIV_INSTRUCTION"); |
| 273 | ourstatus->value.sig = GDB_SIGNAL_ILL; |
| 274 | break; |
| 275 | case EXCEPTION_NONCONTINUABLE_EXCEPTION: |
| 276 | DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_NONCONTINUABLE_EXCEPTION"); |
| 277 | ourstatus->value.sig = GDB_SIGNAL_ILL; |
| 278 | break; |
| 279 | case MS_VC_EXCEPTION: |
| 280 | DEBUG_EXCEPTION_SIMPLE ("MS_VC_EXCEPTION"); |
| 281 | if (handle_ms_vc_exception (rec)) |
| 282 | { |
| 283 | ourstatus->value.sig = GDB_SIGNAL_TRAP; |
| 284 | result = HANDLE_EXCEPTION_IGNORED; |
| 285 | break; |
| 286 | } |
| 287 | /* treat improperly formed exception as unknown */ |
| 288 | /* FALLTHROUGH */ |
| 289 | default: |
| 290 | /* Treat unhandled first chance exceptions specially. */ |
| 291 | if (current_event.u.Exception.dwFirstChance) |
| 292 | return HANDLE_EXCEPTION_UNHANDLED; |
| 293 | debug_printf ("gdb: unknown target exception 0x%08x at %s\n", |
| 294 | (unsigned) current_event.u.Exception.ExceptionRecord.ExceptionCode, |
| 295 | host_address_to_string ( |
| 296 | current_event.u.Exception.ExceptionRecord.ExceptionAddress)); |
| 297 | ourstatus->value.sig = GDB_SIGNAL_UNKNOWN; |
| 298 | break; |
| 299 | } |
| 300 | |
| 301 | last_sig = ourstatus->value.sig; |
| 302 | return result; |
| 303 | |
| 304 | #undef DEBUG_EXCEPTION_SIMPLE |
| 305 | } |
| 306 | |
| 307 | /* See nat/windows-nat.h. */ |
| 308 | |
| 309 | bool |
| 310 | matching_pending_stop (bool debug_events) |
| 311 | { |
| 312 | /* If there are pending stops, and we might plausibly hit one of |
| 313 | them, we don't want to actually continue the inferior -- we just |
| 314 | want to report the stop. In this case, we just pretend to |
| 315 | continue. See the comment by the definition of "pending_stops" |
| 316 | for details on why this is needed. */ |
| 317 | for (const auto &item : pending_stops) |
| 318 | { |
| 319 | if (desired_stop_thread_id == -1 |
| 320 | || desired_stop_thread_id == item.thread_id) |
| 321 | { |
| 322 | DEBUG_EVENTS (("windows_continue - pending stop anticipated, " |
| 323 | "desired=0x%x, item=0x%x\n", |
| 324 | desired_stop_thread_id, item.thread_id)); |
| 325 | return true; |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | return false; |
| 330 | } |
| 331 | |
| 332 | /* See nat/windows-nat.h. */ |
| 333 | |
| 334 | gdb::optional<pending_stop> |
| 335 | fetch_pending_stop (bool debug_events) |
| 336 | { |
| 337 | gdb::optional<pending_stop> result; |
| 338 | for (auto iter = pending_stops.begin (); |
| 339 | iter != pending_stops.end (); |
| 340 | ++iter) |
| 341 | { |
| 342 | if (desired_stop_thread_id == -1 |
| 343 | || desired_stop_thread_id == iter->thread_id) |
| 344 | { |
| 345 | result = *iter; |
| 346 | current_event = iter->event; |
| 347 | |
| 348 | DEBUG_EVENTS (("get_windows_debug_event - " |
| 349 | "pending stop found in 0x%x (desired=0x%x)\n", |
| 350 | iter->thread_id, desired_stop_thread_id)); |
| 351 | |
| 352 | pending_stops.erase (iter); |
| 353 | break; |
| 354 | } |
| 355 | } |
| 356 | |
| 357 | return result; |
| 358 | } |
| 359 | |
| 360 | /* See nat/windows-nat.h. */ |
| 361 | |
| 362 | BOOL |
| 363 | continue_last_debug_event (DWORD continue_status, bool debug_events) |
| 364 | { |
| 365 | DEBUG_EVENTS (("ContinueDebugEvent (cpid=%d, ctid=0x%x, %s);\n", |
| 366 | (unsigned) last_wait_event.dwProcessId, |
| 367 | (unsigned) last_wait_event.dwThreadId, |
| 368 | continue_status == DBG_CONTINUE ? |
| 369 | "DBG_CONTINUE" : "DBG_EXCEPTION_NOT_HANDLED")); |
| 370 | |
| 371 | return ContinueDebugEvent (last_wait_event.dwProcessId, |
| 372 | last_wait_event.dwThreadId, |
| 373 | continue_status); |
| 374 | } |
| 375 | |
| 376 | /* See nat/windows-nat.h. */ |
| 377 | |
| 378 | BOOL |
| 379 | wait_for_debug_event (DEBUG_EVENT *event, DWORD timeout) |
| 380 | { |
| 381 | BOOL result = WaitForDebugEvent (event, timeout); |
| 382 | if (result) |
| 383 | last_wait_event = *event; |
| 384 | return result; |
| 385 | } |
| 386 | |
| 387 | } |