mono/sgen/sgen-protocol.c

   1 /**
   2  * \file
   3  * Binary protocol of internal activity, to aid 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-workers.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(HOST_WIN32)
  27 #include <windows.h>
  28 #elif defined(HAVE_UNISTD_H)
  29 #include <unistd.h>
  30 #include <fcntl.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(HOST_WIN32)
 100         binary_protocol_file = CreateFileA (filename, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 101 #elif defined(HAVE_UNISTD_H)
 102         do {
 103                 binary_protocol_file = open (filename, O_CREAT | O_WRONLY, 0644);
 104                 if (binary_protocol_file == -1) {
 105                         if (errno != EINTR)
 106                                 break; /* Failed */
 107 #ifdef F_SETLK
 108                 } else if (fcntl (binary_protocol_file, F_SETLK, &lock) == -1) {
 109                         /* The lock for the file is already taken. Fail */
 110                         close (binary_protocol_file);
 111                         binary_protocol_file = -1;
 112                         break;
 113 #endif
 114                 } else {
 115                         /* We have acquired the lock. Truncate the file */
 116                         ftruncate (binary_protocol_file, 0);
 117                 }
 118         } while (binary_protocol_file == -1);
 119 #else
 120         g_error ("sgen binary protocol: not supported");
 121 #endif
 122         if (binary_protocol_file == invalid_file_value && assert_on_failure)
 123                 g_error ("sgen binary protocol: failed to open file");
 124
 125         if (file_size_limit > 0)
 126                 free_filename (filename);
 127 }
 128
 129 void
 130 sgen_binary_protocol_init (const char *filename, long long limit)
 131 {
 132         file_size_limit = limit;
 133
 134         /* Original name length + . + pid length in hex + null terminator */
 135         filename_or_prefix = g_strdup_printf ("%s", filename);
 136         binary_protocol_open_file (FALSE);
 137
 138         if (binary_protocol_file == invalid_file_value) {
 139                 /* Another process owns the file, try adding the pid suffix to the filename */
 140                 gint32 pid = mono_process_current_pid ();
 141                 g_free (filename_or_prefix);
 142                 filename_or_prefix = g_strdup_printf ("%s.%x", filename, pid);
 143                 binary_protocol_open_file (TRUE);
 144         }
 145
 146         /* If we have a file size limit, we might need to open additional files */
 147         if (file_size_limit == 0)
 148                 g_free (filename_or_prefix);
 149
 150         sgen_binary_protocol_header (PROTOCOL_HEADER_CHECK, PROTOCOL_HEADER_VERSION, SIZEOF_VOID_P, G_BYTE_ORDER == G_LITTLE_ENDIAN);
 151 }
 152
 153 gboolean
 154 sgen_binary_protocol_is_enabled (void)
 155 {
 156         return binary_protocol_file != invalid_file_value;
 157 }
 158
 159 static void
 160 close_binary_protocol_file (void)
 161 {
 162 #if defined(HOST_WIN32)
 163         CloseHandle (binary_protocol_file);
 164 #elif defined(HAVE_UNISTD_H)
 165         while (close (binary_protocol_file) == -1 && errno == EINTR)
 166                 ;
 167 #endif
 168         binary_protocol_file = invalid_file_value;
 169 }
 170
 171 static gboolean
 172 try_lock_exclusive (void)
 173 {
 174         do {
 175                 if (binary_protocol_use_count)
 176                         return FALSE;
 177         } while (mono_atomic_cas_i32 (&binary_protocol_use_count, -1, 0) != 0);
 178         mono_memory_barrier ();
 179         return TRUE;
 180 }
 181
 182 static void
 183 unlock_exclusive (void)
 184 {
 185         mono_memory_barrier ();
 186         SGEN_ASSERT (0, binary_protocol_use_count == -1, "Exclusively locked count must be -1");
 187         if (mono_atomic_cas_i32 (&binary_protocol_use_count, 0, -1) != -1)
 188                 SGEN_ASSERT (0, FALSE, "Somebody messed with the exclusive lock");
 189 }
 190
 191 static void
 192 lock_recursive (void)
 193 {
 194         int old_count;
 195         do {
 196         retry:
 197                 old_count = binary_protocol_use_count;
 198                 if (old_count < 0) {
 199                         /* Exclusively locked - retry */
 200                         /* FIXME: short back-off */
 201                         goto retry;
 202                 }
 203         } while (mono_atomic_cas_i32 (&binary_protocol_use_count, old_count + 1, old_count) != old_count);
 204         mono_memory_barrier ();
 205 }
 206
 207 static void
 208 unlock_recursive (void)
 209 {
 210         int old_count;
 211         mono_memory_barrier ();
 212         do {
 213                 old_count = binary_protocol_use_count;
 214                 SGEN_ASSERT (0, old_count > 0, "Locked use count must be at least 1");
 215         } while (mono_atomic_cas_i32 (&binary_protocol_use_count, old_count - 1, old_count) != old_count);
 216 }
 217
 218 static void
 219 binary_protocol_flush_buffer (BinaryProtocolBuffer *buffer)
 220 {
 221         size_t to_write = buffer->index;
 222         size_t written = 0;
 223         g_assert (buffer->index > 0);
 224
 225         while (binary_protocol_file != invalid_file_value && written < to_write) {
 226 #if defined(HOST_WIN32)
 227                 DWORD tmp_written;
 228                 if (WriteFile (binary_protocol_file, buffer->buffer + written, to_write - written, &tmp_written, NULL))
 229                         written += tmp_written;
 230 #elif defined(HAVE_UNISTD_H)
 231                 ssize_t ret = write (binary_protocol_file, buffer->buffer + written, to_write - written);
 232                 if (ret >= 0)
 233                         written += ret;
 234                 else if (errno == EINTR)
 235                         continue;
 236 #endif
 237                 else
 238                         close_binary_protocol_file ();
 239         }
 240
 241         current_file_size += buffer->index;
 242
 243         sgen_free_os_memory (buffer, sizeof (BinaryProtocolBuffer), SGEN_ALLOC_INTERNAL, MONO_MEM_ACCOUNT_SGEN_BINARY_PROTOCOL);
 244 }
 245
 246 static void
 247 binary_protocol_check_file_overflow (void)
 248 {
 249         if (file_size_limit <= 0 || current_file_size < file_size_limit)
 250                 return;
 251
 252         close_binary_protocol_file ();
 253
 254         if (current_file_index > 0) {
 255                 char *filename = filename_for_index (current_file_index - 1);
 256                 unlink (filename);
 257                 free_filename (filename);
 258         }
 259
 260         ++current_file_index;
 261         current_file_size = 0;
 262
 263         binary_protocol_open_file (TRUE);
 264 }
 265
 266 /*
 267  * Flushing buffers takes an exclusive lock, so it must only be done when the world is
 268  * stopped, otherwise we might end up with a deadlock because a stopped thread owns the
 269  * lock.
 270  *
 271  * The protocol entries that do flush have `FLUSH()` in their definition.
 272  */
 273 gboolean
 274 sgen_binary_protocol_flush_buffers (gboolean force)
 275 {
 276         int num_buffers = 0, i;
 277         BinaryProtocolBuffer *header;
 278         BinaryProtocolBuffer *buf;
 279         BinaryProtocolBuffer **bufs;
 280
 281         if (binary_protocol_file == invalid_file_value)
 282                 return FALSE;
 283
 284         if (!force && !try_lock_exclusive ())
 285                 return FALSE;
 286
 287         header = binary_protocol_buffers;
 288         for (buf = header; buf != NULL; buf = buf->next)
 289                 ++num_buffers;
 290         bufs = (BinaryProtocolBuffer **)sgen_alloc_internal_dynamic (num_buffers * sizeof (BinaryProtocolBuffer*), INTERNAL_MEM_BINARY_PROTOCOL, TRUE);
 291         for (buf = header, i = 0; buf != NULL; buf = buf->next, i++)
 292                 bufs [i] = buf;
 293         SGEN_ASSERT (0, i == num_buffers, "Binary protocol buffer count error");
 294
 295         /*
 296          * This might be incorrect when forcing, but all bets are off in that case, anyway,
 297          * because we're trying to figure out a bug in the debugger.
 298          */
 299         binary_protocol_buffers = NULL;
 300
 301         for (i = num_buffers - 1; i >= 0; --i) {
 302                 binary_protocol_flush_buffer (bufs [i]);
 303                 binary_protocol_check_file_overflow ();
 304         }
 305
 306         sgen_free_internal_dynamic (buf, num_buffers * sizeof (BinaryProtocolBuffer*), INTERNAL_MEM_BINARY_PROTOCOL);
 307
 308         if (!force)
 309                 unlock_exclusive ();
 310
 311         return TRUE;
 312 }
 313
 314 static BinaryProtocolBuffer*
 315 binary_protocol_get_buffer (int length)
 316 {
 317         BinaryProtocolBuffer *buffer, *new_buffer;
 318  retry:
 319         buffer = binary_protocol_buffers;
 320         if (buffer && buffer->index + length <= BINARY_PROTOCOL_BUFFER_SIZE)
 321                 return buffer;
 322
 323         new_buffer = (BinaryProtocolBuffer *)sgen_alloc_os_memory (sizeof (BinaryProtocolBuffer), (SgenAllocFlags)(SGEN_ALLOC_INTERNAL | SGEN_ALLOC_ACTIVATE), "debugging memory", MONO_MEM_ACCOUNT_SGEN_BINARY_PROTOCOL);
 324         new_buffer->next = buffer;
 325         new_buffer->index = 0;
 326
 327         if (mono_atomic_cas_ptr ((void**)&binary_protocol_buffers, new_buffer, buffer) != buffer) {
 328                 sgen_free_os_memory (new_buffer, sizeof (BinaryProtocolBuffer), SGEN_ALLOC_INTERNAL, MONO_MEM_ACCOUNT_SGEN_BINARY_PROTOCOL);
 329                 goto retry;
 330         }
 331
 332         return new_buffer;
 333 }
 334
 335 static void
 336 protocol_entry (unsigned char type, gpointer data, int size)
 337 {
 338         int index;
 339         gboolean include_worker_index = type != PROTOCOL_ID (binary_protocol_header);
 340         int entry_size = size + 1 + (include_worker_index ? 1 : 0); // type + worker_index + size
 341         BinaryProtocolBuffer *buffer;
 342
 343         if (binary_protocol_file == invalid_file_value)
 344                 return;
 345
 346         lock_recursive ();
 347
 348  retry:
 349         buffer = binary_protocol_get_buffer (size + 1);
 350  retry_same_buffer:
 351         index = buffer->index;
 352         if (index + entry_size > BINARY_PROTOCOL_BUFFER_SIZE)
 353                 goto retry;
 354
 355         if (mono_atomic_cas_i32 (&buffer->index, index + entry_size, index) != index)
 356                 goto retry_same_buffer;
 357
 358         /* FIXME: if we're interrupted at this point, we have a buffer
 359            entry that contains random data. */
 360
 361         buffer->buffer [index++] = type;
 362         /* We should never change the header format */
 363         if (include_worker_index) {
 364                 int worker_index;
 365                 MonoNativeThreadId tid = mono_native_thread_id_get ();
 366                 /*
 367                  * If the thread is not a worker thread we insert 0, which is interpreted
 368                  * as gc thread. Worker indexes are 1 based.
 369                  */
 370                 worker_index = sgen_thread_pool_is_thread_pool_thread (tid);
 371                 /* FIXME Consider using different index bases for different thread pools */
 372                 buffer->buffer [index++] = (unsigned char) worker_index;
 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 sgen_ ## 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 sgen_ ## 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 sgen_ ## 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 sgen_ ## 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 sgen_ ## 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 sgen_ ## 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 sgen_ ## 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                 sgen_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 */