mono/sgen/sgen-protocol.c

   1 /*
   2  * sgen-protocol.c: Binary protocol of internal activity, to aid
   3  * debugging.
   4  *
   5  * Copyright 2001-2003 Ximian, Inc
   6  * Copyright 2003-2010 Novell, Inc.
   7  * Copyright (C) 2012 Xamarin Inc
   8  *
   9  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  10  */
  11
  12 #ifdef HAVE_SGEN_GC
  13
  14 #include "config.h"
  15 #include "sgen-conf.h"
  16 #include "sgen-gc.h"
  17 #include "sgen-protocol.h"
  18 #include "sgen-memory-governor.h"
  19 #include "sgen-thread-pool.h"
  20 #include "sgen-client.h"
  21 #include "mono/utils/mono-membar.h"
  22 #include "mono/utils/mono-proclib.h"
  23
  24 #include <errno.h>
  25 #include <string.h>
  26 #if defined(HAVE_UNISTD_H)
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #elif defined(HOST_WIN32)
  30 #include <windows.h>
  31 #endif
  32
  33 #if defined(HOST_WIN32)
  34 static const HANDLE invalid_file_value = INVALID_HANDLE_VALUE;
  35 /* If valid, dump binary protocol to this file */
  36 static HANDLE binary_protocol_file = INVALID_HANDLE_VALUE;
  37 #else
  38 static const int invalid_file_value = -1;
  39 static int binary_protocol_file = -1;
  40 #endif
  41
  42 /* We set this to -1 to indicate an exclusive lock */
  43 static volatile int binary_protocol_use_count = 0;
  44
  45 #define BINARY_PROTOCOL_BUFFER_SIZE     (65536 - 2 * 8)
  46
  47 typedef struct _BinaryProtocolBuffer BinaryProtocolBuffer;
  48 struct _BinaryProtocolBuffer {
  49         BinaryProtocolBuffer * volatile next;
  50         volatile int index;
  51         unsigned char buffer [BINARY_PROTOCOL_BUFFER_SIZE];
  52 };
  53
  54 static BinaryProtocolBuffer * volatile binary_protocol_buffers = NULL;
  55
  56 static char* filename_or_prefix = NULL;
  57 static int current_file_index = 0;
  58 static long long current_file_size = 0;
  59 static long long file_size_limit;
  60
  61 static char*
  62 filename_for_index (int index)
  63 {
  64         char *filename;
  65
  66         SGEN_ASSERT (0, file_size_limit > 0, "Indexed binary protocol filename must only be used with file size limit");
  67
  68         filename = (char *)sgen_alloc_internal_dynamic (strlen (filename_or_prefix) + 32, INTERNAL_MEM_BINARY_PROTOCOL, TRUE);
  69         sprintf (filename, "%s.%d", filename_or_prefix, index);
  70
  71         return filename;
  72 }
  73
  74 static void
  75 free_filename (char *filename)
  76 {
  77         SGEN_ASSERT (0, file_size_limit > 0, "Indexed binary protocol filename must only be used with file size limit");
  78
  79         sgen_free_internal_dynamic (filename, strlen (filename_or_prefix) + 32, INTERNAL_MEM_BINARY_PROTOCOL);
  80 }
  81
  82 static void
  83 binary_protocol_open_file (gboolean assert_on_failure)
  84 {
  85         char *filename;
  86 #ifdef F_SETLK
  87         struct flock lock;
  88         lock.l_type = F_WRLCK;
  89         lock.l_whence = SEEK_SET;
  90         lock.l_start = 0;
  91         lock.l_len = 0;
  92 #endif
  93
  94         if (file_size_limit > 0)
  95                 filename = filename_for_index (current_file_index);
  96         else
  97                 filename = filename_or_prefix;
  98
  99 #if defined(HAVE_UNISTD_H)
 100         do {
 101                 binary_protocol_file = open (filename, O_CREAT | O_WRONLY, 0644);
 102                 if (binary_protocol_file == -1) {
 103                         if (errno != EINTR)
 104                                 break; /* Failed */
 105 #ifdef F_SETLK
 106                 } else if (fcntl (binary_protocol_file, F_SETLK, &lock) == -1) {
 107                         /* The lock for the file is already taken. Fail */
 108                         close (binary_protocol_file);
 109                         binary_protocol_file = -1;
 110                         break;
 111 #endif
 112                 } else {
 113                         /* We have acquired the lock. Truncate the file */
 114                         ftruncate (binary_protocol_file, 0);
 115                 }
 116         } while (binary_protocol_file == -1);
 117 #elif defined(HOST_WIN32)
 118         binary_protocol_file = CreateFileA (filename, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 119 #else
 120         g_error ("sgen binary protocol: not supported");
 121 #endif
 122
 123         if (binary_protocol_file == invalid_file_value && assert_on_failure)
 124                 g_error ("sgen binary protocol: failed to open file");
 125
 126         if (file_size_limit > 0)
 127                 free_filename (filename);
 128 }
 129
 130 void
 131 binary_protocol_init (const char *filename, long long limit)
 132 {
 133         file_size_limit = limit;
 134
 135         /* Original name length + . + pid length in hex + null terminator */
 136         filename_or_prefix = g_strdup_printf ("%s", filename);
 137         binary_protocol_open_file (FALSE);
 138
 139         if (binary_protocol_file == invalid_file_value) {
 140                 /* Another process owns the file, try adding the pid suffix to the filename */
 141                 gint32 pid = mono_process_current_pid ();
 142                 g_free (filename_or_prefix);
 143                 filename_or_prefix = g_strdup_printf ("%s.%x", filename, pid);
 144                 binary_protocol_open_file (TRUE);
 145         }
 146
 147         /* If we have a file size limit, we might need to open additional files */
 148         if (file_size_limit == 0)
 149                 g_free (filename_or_prefix);
 150
 151         binary_protocol_header (PROTOCOL_HEADER_CHECK, PROTOCOL_HEADER_VERSION, SIZEOF_VOID_P, G_BYTE_ORDER == G_LITTLE_ENDIAN);
 152 }
 153
 154 gboolean
 155 binary_protocol_is_enabled (void)
 156 {
 157         return binary_protocol_file != invalid_file_value;
 158 }
 159
 160 static void
 161 close_binary_protocol_file (void)
 162 {
 163 #if defined(HAVE_UNISTD_H)
 164         while (close (binary_protocol_file) == -1 && errno == EINTR)
 165                 ;
 166 #elif defined(HOST_WIN32)
 167         CloseHandle (binary_protocol_file);
 168 #endif
 169         binary_protocol_file = invalid_file_value;
 170 }
 171
 172 static gboolean
 173 try_lock_exclusive (void)
 174 {
 175         do {
 176                 if (binary_protocol_use_count)
 177                         return FALSE;
 178         } while (InterlockedCompareExchange (&binary_protocol_use_count, -1, 0) != 0);
 179         mono_memory_barrier ();
 180         return TRUE;
 181 }
 182
 183 static void
 184 unlock_exclusive (void)
 185 {
 186         mono_memory_barrier ();
 187         SGEN_ASSERT (0, binary_protocol_use_count == -1, "Exclusively locked count must be -1");
 188         if (InterlockedCompareExchange (&binary_protocol_use_count, 0, -1) != -1)
 189                 SGEN_ASSERT (0, FALSE, "Somebody messed with the exclusive lock");
 190 }
 191
 192 static void
 193 lock_recursive (void)
 194 {
 195         int old_count;
 196         do {
 197         retry:
 198                 old_count = binary_protocol_use_count;
 199                 if (old_count < 0) {
 200                         /* Exclusively locked - retry */
 201                         /* FIXME: short back-off */
 202                         goto retry;
 203                 }
 204         } while (InterlockedCompareExchange (&binary_protocol_use_count, old_count + 1, old_count) != old_count);
 205         mono_memory_barrier ();
 206 }
 207
 208 static void
 209 unlock_recursive (void)
 210 {
 211         int old_count;
 212         mono_memory_barrier ();
 213         do {
 214                 old_count = binary_protocol_use_count;
 215                 SGEN_ASSERT (0, old_count > 0, "Locked use count must be at least 1");
 216         } while (InterlockedCompareExchange (&binary_protocol_use_count, old_count - 1, old_count) != old_count);
 217 }
 218
 219 static void
 220 binary_protocol_flush_buffer (BinaryProtocolBuffer *buffer)
 221 {
 222         ssize_t ret;
 223         size_t to_write = buffer->index;
 224         size_t written = 0;
 225         g_assert (buffer->index > 0);
 226
 227         while (written < to_write) {
 228 #if defined(HAVE_UNISTD_H)
 229                 ret = write (binary_protocol_file, buffer->buffer + written, to_write - written);
 230                 if (ret >= 0)
 231                         written += ret;
 232                 else if (errno == EINTR)
 233                         continue;
 234                 else
 235                         close_binary_protocol_file ();
 236 #elif defined(HOST_WIN32)
 237                 int tmp_written;
 238                 if (WriteFile (binary_protocol_file, buffer->buffer + written, to_write - written, &tmp_written, NULL))
 239                         written += tmp_written;
 240                 else
 241                         close_binary_protocol_file ();
 242 #endif
 243         }
 244
 245         current_file_size += buffer->index;
 246
 247         sgen_free_os_memory (buffer, sizeof (BinaryProtocolBuffer), SGEN_ALLOC_INTERNAL, MONO_MEM_ACCOUNT_SGEN_BINARY_PROTOCOL);
 248 }
 249
 250 static void
 251 binary_protocol_check_file_overflow (void)
 252 {
 253         if (file_size_limit <= 0 || current_file_size < file_size_limit)
 254                 return;
 255
 256         close_binary_protocol_file ();
 257
 258         if (current_file_index > 0) {
 259                 char *filename = filename_for_index (current_file_index - 1);
 260                 unlink (filename);
 261                 free_filename (filename);
 262         }
 263
 264         ++current_file_index;
 265         current_file_size = 0;
 266
 267         binary_protocol_open_file (TRUE);
 268 }
 269
 270 /*
 271  * Flushing buffers takes an exclusive lock, so it must only be done when the world is
 272  * stopped, otherwise we might end up with a deadlock because a stopped thread owns the
 273  * lock.
 274  *
 275  * The protocol entries that do flush have `FLUSH()` in their definition.
 276  */
 277 gboolean
 278 binary_protocol_flush_buffers (gboolean force)
 279 {
 280         int num_buffers = 0, i;
 281         BinaryProtocolBuffer *header;
 282         BinaryProtocolBuffer *buf;
 283         BinaryProtocolBuffer **bufs;
 284
 285         if (binary_protocol_file == invalid_file_value)
 286                 return FALSE;
 287
 288         if (!force && !try_lock_exclusive ())
 289                 return FALSE;
 290
 291         header = binary_protocol_buffers;
 292         for (buf = header; buf != NULL; buf = buf->next)
 293                 ++num_buffers;
 294         bufs = (BinaryProtocolBuffer **)sgen_alloc_internal_dynamic (num_buffers * sizeof (BinaryProtocolBuffer*), INTERNAL_MEM_BINARY_PROTOCOL, TRUE);
 295         for (buf = header, i = 0; buf != NULL; buf = buf->next, i++)
 296                 bufs [i] = buf;
 297         SGEN_ASSERT (0, i == num_buffers, "Binary protocol buffer count error");
 298
 299         /*
 300          * This might be incorrect when forcing, but all bets are off in that case, anyway,
 301          * because we're trying to figure out a bug in the debugger.
 302          */
 303         binary_protocol_buffers = NULL;
 304
 305         for (i = num_buffers - 1; i >= 0; --i) {
 306                 binary_protocol_flush_buffer (bufs [i]);
 307                 binary_protocol_check_file_overflow ();
 308         }
 309
 310         sgen_free_internal_dynamic (buf, num_buffers * sizeof (BinaryProtocolBuffer*), INTERNAL_MEM_BINARY_PROTOCOL);
 311
 312         if (!force)
 313                 unlock_exclusive ();
 314
 315         return TRUE;
 316 }
 317
 318 static BinaryProtocolBuffer*
 319 binary_protocol_get_buffer (int length)
 320 {
 321         BinaryProtocolBuffer *buffer, *new_buffer;
 322  retry:
 323         buffer = binary_protocol_buffers;
 324         if (buffer && buffer->index + length <= BINARY_PROTOCOL_BUFFER_SIZE)
 325                 return buffer;
 326
 327         new_buffer = (BinaryProtocolBuffer *)sgen_alloc_os_memory (sizeof (BinaryProtocolBuffer), (SgenAllocFlags)(SGEN_ALLOC_INTERNAL | SGEN_ALLOC_ACTIVATE), "debugging memory", MONO_MEM_ACCOUNT_SGEN_BINARY_PROTOCOL);
 328         new_buffer->next = buffer;
 329         new_buffer->index = 0;
 330
 331         if (InterlockedCompareExchangePointer ((void**)&binary_protocol_buffers, new_buffer, buffer) != buffer) {
 332                 sgen_free_os_memory (new_buffer, sizeof (BinaryProtocolBuffer), SGEN_ALLOC_INTERNAL, MONO_MEM_ACCOUNT_SGEN_BINARY_PROTOCOL);
 333                 goto retry;
 334         }
 335
 336         return new_buffer;
 337 }
 338
 339 static void
 340 protocol_entry (unsigned char type, gpointer data, int size)
 341 {
 342         int index;
 343         gboolean include_worker_index = type != PROTOCOL_ID (binary_protocol_header);
 344         int entry_size = size + 1 + (include_worker_index ? 1 : 0); // type + worker_index + size
 345         BinaryProtocolBuffer *buffer;
 346
 347         if (binary_protocol_file == invalid_file_value)
 348                 return;
 349
 350         lock_recursive ();
 351
 352  retry:
 353         buffer = binary_protocol_get_buffer (size + 1);
 354  retry_same_buffer:
 355         index = buffer->index;
 356         if (index + entry_size > BINARY_PROTOCOL_BUFFER_SIZE)
 357                 goto retry;
 358
 359         if (InterlockedCompareExchange (&buffer->index, index + entry_size, index) != index)
 360                 goto retry_same_buffer;
 361
 362         /* FIXME: if we're interrupted at this point, we have a buffer
 363            entry that contains random data. */
 364
 365         buffer->buffer [index++] = type;
 366         /* We should never change the header format */
 367         if (include_worker_index) {
 368                 /*
 369                  * If the thread is not a worker thread we insert 0, which is interpreted
 370                  * as gc thread. Worker indexes are 1 based.
 371                  */
 372                 buffer->buffer [index++] = (unsigned char) sgen_thread_pool_is_thread_pool_thread (mono_native_thread_id_get ());
 373         }
 374         memcpy (buffer->buffer + index, data, size);
 375         index += size;
 376
 377         g_assert (index <= BINARY_PROTOCOL_BUFFER_SIZE);
 378
 379         unlock_recursive ();
 380 }
 381
 382 #define TYPE_INT int
 383 #define TYPE_LONGLONG long long
 384 #define TYPE_SIZE size_t
 385 #define TYPE_POINTER gpointer
 386 #define TYPE_BOOL gboolean
 387
 388 #define BEGIN_PROTOCOL_ENTRY0(method) \
 389         void method (void) { \
 390                 int __type = PROTOCOL_ID(method); \
 391                 gpointer __data = NULL; \
 392                 int __size = 0; \
 393                 CLIENT_PROTOCOL_NAME (method) ();
 394 #define BEGIN_PROTOCOL_ENTRY1(method,t1,f1) \
 395         void method (t1 f1) { \
 396                 PROTOCOL_STRUCT(method) __entry = { f1 }; \
 397                 int __type = PROTOCOL_ID(method); \
 398                 gpointer __data = &__entry; \
 399                 int __size = sizeof (PROTOCOL_STRUCT(method)); \
 400                 CLIENT_PROTOCOL_NAME (method) (f1);
 401 #define BEGIN_PROTOCOL_ENTRY2(method,t1,f1,t2,f2) \
 402         void method (t1 f1, t2 f2) { \
 403                 PROTOCOL_STRUCT(method) __entry = { f1, f2 }; \
 404                 int __type = PROTOCOL_ID(method); \
 405                 gpointer __data = &__entry; \
 406                 int __size = sizeof (PROTOCOL_STRUCT(method)); \
 407                 CLIENT_PROTOCOL_NAME (method) (f1, f2);
 408 #define BEGIN_PROTOCOL_ENTRY3(method,t1,f1,t2,f2,t3,f3) \
 409         void method (t1 f1, t2 f2, t3 f3) { \
 410                 PROTOCOL_STRUCT(method) __entry = { f1, f2, f3 }; \
 411                 int __type = PROTOCOL_ID(method); \
 412                 gpointer __data = &__entry; \
 413                 int __size = sizeof (PROTOCOL_STRUCT(method)); \
 414                 CLIENT_PROTOCOL_NAME (method) (f1, f2, f3);
 415 #define BEGIN_PROTOCOL_ENTRY4(method,t1,f1,t2,f2,t3,f3,t4,f4) \
 416         void method (t1 f1, t2 f2, t3 f3, t4 f4) { \
 417                 PROTOCOL_STRUCT(method) __entry = { f1, f2, f3, f4 }; \
 418                 int __type = PROTOCOL_ID(method); \
 419                 gpointer __data = &__entry; \
 420                 int __size = sizeof (PROTOCOL_STRUCT(method)); \
 421                 CLIENT_PROTOCOL_NAME (method) (f1, f2, f3, f4);
 422 #define BEGIN_PROTOCOL_ENTRY5(method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5) \
 423         void method (t1 f1, t2 f2, t3 f3, t4 f4, t5 f5) { \
 424                 PROTOCOL_STRUCT(method) __entry = { f1, f2, f3, f4, f5 }; \
 425                 int __type = PROTOCOL_ID(method); \
 426                 gpointer __data = &__entry; \
 427                 int __size = sizeof (PROTOCOL_STRUCT(method)); \
 428                 CLIENT_PROTOCOL_NAME (method) (f1, f2, f3, f4, f5);
 429 #define BEGIN_PROTOCOL_ENTRY6(method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5,t6,f6) \
 430         void method (t1 f1, t2 f2, t3 f3, t4 f4, t5 f5, t6 f6) { \
 431                 PROTOCOL_STRUCT(method) __entry = { f1, f2, f3, f4, f5, f6 }; \
 432                 int __type = PROTOCOL_ID(method); \
 433                 gpointer __data = &__entry; \
 434                 int __size = sizeof (PROTOCOL_STRUCT(method)); \
 435                 CLIENT_PROTOCOL_NAME (method) (f1, f2, f3, f4, f5, f6);
 436
 437 #define DEFAULT_PRINT()
 438 #define CUSTOM_PRINT(_)
 439
 440 #define IS_ALWAYS_MATCH(_)
 441 #define MATCH_INDEX(_)
 442 #define IS_VTABLE_MATCH(_)
 443
 444 #define END_PROTOCOL_ENTRY \
 445                 protocol_entry (__type, __data, __size); \
 446         }
 447
 448 #define END_PROTOCOL_ENTRY_FLUSH \
 449                 protocol_entry (__type, __data, __size); \
 450                 binary_protocol_flush_buffers (FALSE); \
 451         }
 452
 453 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
 454 #define BEGIN_PROTOCOL_ENTRY_HEAVY0(method) \
 455         BEGIN_PROTOCOL_ENTRY0 (method)
 456 #define BEGIN_PROTOCOL_ENTRY_HEAVY1(method,t1,f1) \
 457         BEGIN_PROTOCOL_ENTRY1 (method,t1,f1)
 458 #define BEGIN_PROTOCOL_ENTRY_HEAVY2(method,t1,f1,t2,f2) \
 459         BEGIN_PROTOCOL_ENTRY2 (method,t1,f1,t2,f2)
 460 #define BEGIN_PROTOCOL_ENTRY_HEAVY3(method,t1,f1,t2,f2,t3,f3) \
 461         BEGIN_PROTOCOL_ENTRY3 (method,t1,f1,t2,f2,t3,f3)
 462 #define BEGIN_PROTOCOL_ENTRY_HEAVY4(method,t1,f1,t2,f2,t3,f3,t4,f4) \
 463         BEGIN_PROTOCOL_ENTRY4 (method,t1,f1,t2,f2,t3,f3,t4,f4)
 464 #define BEGIN_PROTOCOL_ENTRY_HEAVY5(method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5) \
 465         BEGIN_PROTOCOL_ENTRY5 (method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5)
 466 #define BEGIN_PROTOCOL_ENTRY_HEAVY6(method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5,t6,f6) \
 467         BEGIN_PROTOCOL_ENTRY6 (method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5,t6,f6)
 468
 469 #define END_PROTOCOL_ENTRY_HEAVY \
 470         END_PROTOCOL_ENTRY
 471 #else
 472 #define BEGIN_PROTOCOL_ENTRY_HEAVY0(method)
 473 #define BEGIN_PROTOCOL_ENTRY_HEAVY1(method,t1,f1)
 474 #define BEGIN_PROTOCOL_ENTRY_HEAVY2(method,t1,f1,t2,f2)
 475 #define BEGIN_PROTOCOL_ENTRY_HEAVY3(method,t1,f1,t2,f2,t3,f3)
 476 #define BEGIN_PROTOCOL_ENTRY_HEAVY4(method,t1,f1,t2,f2,t3,f3,t4,f4)
 477 #define BEGIN_PROTOCOL_ENTRY_HEAVY5(method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5)
 478 #define BEGIN_PROTOCOL_ENTRY_HEAVY6(method,t1,f1,t2,f2,t3,f3,t4,f4,t5,f5,t6,f6)
 479
 480 #define END_PROTOCOL_ENTRY_HEAVY
 481 #endif
 482
 483 #include "sgen-protocol-def.h"
 484
 485 #undef TYPE_INT
 486 #undef TYPE_LONGLONG
 487 #undef TYPE_SIZE
 488 #undef TYPE_POINTER
 489 #undef TYPE_BOOL
 490
 491 #endif /* HAVE_SGEN_GC */