linuxthreads/internals.h

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 #ifndef _INTERNALS_H
  16 #define _INTERNALS_H    1
  17
  18 /* Internal data structures */
  19
  20 /* Includes */
  21
  22 #include <limits.h>
  23 #include <setjmp.h>
  24 #include <signal.h>
  25 #include <unistd.h>
  26 #include <sys/types.h>
  27 #include <bits/libc-tsd.h> /* for _LIBC_TSD_KEY_N */
  28
  29 #define __RES_PTHREAD_INTERNAL
  30 #include <resolv.h> /* for per-thread resolver context */
  31
  32
  33 #include "pt-machine.h"
  34 #include "semaphore.h"
  35 #include "../linuxthreads_db/thread_dbP.h"
  36
  37 #ifndef THREAD_GETMEM
  38 # define THREAD_GETMEM(descr, member) descr->member
  39 #endif
  40 #ifndef THREAD_GETMEM_NC
  41 # define THREAD_GETMEM_NC(descr, member) descr->member
  42 #endif
  43 #ifndef THREAD_SETMEM
  44 # define THREAD_SETMEM(descr, member, value) descr->member = (value)
  45 #endif
  46 #ifndef THREAD_SETMEM_NC
  47 # define THREAD_SETMEM_NC(descr, member, value) descr->member = (value)
  48 #endif
  49
  50 /* Arguments passed to thread creation routine */
  51
  52 struct pthread_start_args {
  53   void * (*start_routine)(void *); /* function to run */
  54   void * arg;                   /* its argument */
  55   sigset_t mask;                /* initial signal mask for thread */
  56   int schedpolicy;              /* initial scheduling policy (if any) */
  57   struct sched_param schedparam; /* initial scheduling parameters (if any) */
  58 };
  59
  60
  61 /* We keep thread specific data in a special data structure, a two-level
  62    array.  The top-level array contains pointers to dynamically allocated
  63    arrays of a certain number of data pointers.  So we can implement a
  64    sparse array.  Each dynamic second-level array has
  65         PTHREAD_KEY_2NDLEVEL_SIZE
  66    entries.  This value shouldn't be too large.  */
  67 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  68
  69 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  70    keys in each subarray.  */
  71 #define PTHREAD_KEY_1STLEVEL_SIZE \
  72   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  73    / PTHREAD_KEY_2NDLEVEL_SIZE)
  74
  75 typedef void (*destr_function)(void *);
  76
  77 struct pthread_key_struct {
  78   int in_use;                   /* already allocated? */
  79   destr_function destr;         /* destruction routine */
  80 };
  81
  82
  83 #define PTHREAD_START_ARGS_INITIALIZER(fct) \
  84   { (void *(*) (void *)) fct, NULL, {{0, }}, 0, { 0 } }
  85
  86 /* The type of thread descriptors */
  87
  88 typedef struct _pthread_descr_struct * pthread_descr;
  89
  90 /* Callback interface for removing the thread from waiting on an
  91    object if it is cancelled while waiting or about to wait.
  92    This hold a pointer to the object, and a pointer to a function
  93    which ``extricates'' the thread from its enqueued state.
  94    The function takes two arguments: pointer to the wait object,
  95    and a pointer to the thread. It returns 1 if an extrication
  96    actually occured, and hence the thread must also be signalled.
  97    It returns 0 if the thread had already been extricated. */
  98
  99 typedef struct _pthread_extricate_struct {
 100     void *pu_object;
 101     int (*pu_extricate_func)(void *, pthread_descr);
 102 } pthread_extricate_if;
 103
 104 /* Atomic counter made possible by compare_and_swap */
 105
 106 struct pthread_atomic {
 107   long p_count;
 108   int p_spinlock;
 109 };
 110
 111 /* Context info for read write locks. The pthread_rwlock_info structure
 112    is information about a lock that has been read-locked by the thread
 113    in whose list this structure appears. The pthread_rwlock_context
 114    is embedded in the thread context and contains a pointer to the
 115    head of the list of lock info structures, as well as a count of
 116    read locks that are untracked, because no info structure could be
 117    allocated for them. */
 118
 119 struct _pthread_rwlock_t;
 120
 121 typedef struct _pthread_rwlock_info {
 122   struct _pthread_rwlock_info *pr_next;
 123   struct _pthread_rwlock_t *pr_lock;
 124   int pr_lock_count;
 125 } pthread_readlock_info;
 126
 127 struct _pthread_descr_struct {
 128   union {
 129     struct {
 130       pthread_descr self;       /* Pointer to this structure */
 131     } data;
 132     void *__padding[16];
 133   } p_header;
 134   pthread_descr p_nextlive, p_prevlive;
 135                                 /* Double chaining of active threads */
 136   pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
 137   pthread_descr p_nextlock;     /* can be on a queue and waiting on a lock */
 138   pthread_t p_tid;              /* Thread identifier */
 139   int p_pid;                    /* PID of Unix process */
 140   int p_priority;               /* Thread priority (== 0 if not realtime) */
 141   struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
 142   int p_signal;                 /* last signal received */
 143   sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
 144   sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
 145   char p_terminated;            /* true if terminated e.g. by pthread_exit */
 146   char p_detached;              /* true if detached */
 147   char p_exited;                /* true if the assoc. process terminated */
 148   void * p_retval;              /* placeholder for return value */
 149   int p_retcode;                /* placeholder for return code */
 150   pthread_descr p_joining;      /* thread joining on that thread or NULL */
 151   struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
 152   char p_cancelstate;           /* cancellation state */
 153   char p_canceltype;            /* cancellation type (deferred/async) */
 154   char p_canceled;              /* cancellation request pending */
 155   int * p_errnop;               /* pointer to used errno variable */
 156   int p_errno;                  /* error returned by last system call */
 157   int * p_h_errnop;             /* pointer to used h_errno variable */
 158   int p_h_errno;                /* error returned by last netdb function */
 159   char * p_in_sighandler;       /* stack address of sighandler, or NULL */
 160   char p_sigwaiting;            /* true if a sigwait() is in progress */
 161   struct pthread_start_args p_start_args; /* arguments for thread creation */
 162   void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
 163   void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
 164   int p_userstack;              /* nonzero if the user provided the stack */
 165   void *p_guardaddr;            /* address of guard area or NULL */
 166   size_t p_guardsize;           /* size of guard area */
 167   int p_nr;                     /* Index of descriptor in __pthread_handles */
 168   int p_report_events;          /* Nonzero if events must be reported.  */
 169   td_eventbuf_t p_eventbuf;     /* Data for event.  */
 170   struct pthread_atomic p_resume_count; /* number of times restart() was
 171                                            called on thread */
 172   char p_woken_by_cancel;       /* cancellation performed wakeup */
 173   pthread_extricate_if *p_extricate; /* See above */
 174   pthread_readlock_info *p_readlock_list;  /* List of readlock info structs */
 175   pthread_readlock_info *p_readlock_free;  /* Free list of structs */
 176   int p_untracked_readlock_count;       /* Readlocks not tracked by list */
 177   struct __res_state *p_resp;   /* Pointer to resolver state */
 178   struct __res_state p_res;     /* per-thread resolver state */
 179   /* New elements must be added at the end.  */
 180 } __attribute__ ((aligned(32))); /* We need to align the structure so that
 181                                     doubles are aligned properly.  This is 8
 182                                     bytes on MIPS and 16 bytes on MIPS64.
 183                                     32 bytes might give better cache
 184                                     utilization.  */
 185
 186
 187 /* The type of thread handles. */
 188
 189 typedef struct pthread_handle_struct * pthread_handle;
 190
 191 struct pthread_handle_struct {
 192   struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */
 193   pthread_descr h_descr;        /* Thread descriptor or NULL if invalid */
 194   char * h_bottom;              /* Lowest address in the stack thread */
 195 };
 196
 197 /* The type of messages sent to the thread manager thread */
 198
 199 struct pthread_request {
 200   pthread_descr req_thread;     /* Thread doing the request */
 201   enum {                        /* Request kind */
 202     REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT,
 203     REQ_POST, REQ_DEBUG, REQ_KICK
 204   } req_kind;
 205   union {                       /* Arguments for request */
 206     struct {                    /* For REQ_CREATE: */
 207       const pthread_attr_t * attr; /* thread attributes */
 208       void * (*fn)(void *);     /*   start function */
 209       void * arg;               /*   argument to start function */
 210       sigset_t mask;            /*   signal mask */
 211     } create;
 212     struct {                    /* For REQ_FREE: */
 213       pthread_t thread_id;      /*   identifier of thread to free */
 214     } free;
 215     struct {                    /* For REQ_PROCESS_EXIT: */
 216       int code;                 /*   exit status */
 217     } exit;
 218     void * post;                /* For REQ_POST: the semaphore */
 219   } req_args;
 220 };
 221
 222
 223 /* Signals used for suspend/restart and for cancellation notification.  */
 224
 225 extern int __pthread_sig_restart;
 226 extern int __pthread_sig_cancel;
 227
 228 /* Signal used for interfacing with gdb */
 229
 230 extern int __pthread_sig_debug;
 231
 232 /* Global array of thread handles, used for validating a thread id
 233    and retrieving the corresponding thread descriptor. Also used for
 234    mapping the available stack segments. */
 235
 236 extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX];
 237
 238 /* Descriptor of the initial thread */
 239
 240 extern struct _pthread_descr_struct __pthread_initial_thread;
 241
 242 /* Descriptor of the manager thread */
 243
 244 extern struct _pthread_descr_struct __pthread_manager_thread;
 245
 246 /* Descriptor of the main thread */
 247
 248 extern pthread_descr __pthread_main_thread;
 249
 250 /* Limit between the stack of the initial thread (above) and the
 251    stacks of other threads (below). Aligned on a STACK_SIZE boundary.
 252    Initially 0, meaning that the current thread is (by definition)
 253    the initial thread. */
 254
 255 extern char *__pthread_initial_thread_bos;
 256
 257 /* Indicate whether at least one thread has a user-defined stack (if 1),
 258    or all threads have stacks supplied by LinuxThreads (if 0). */
 259
 260 extern int __pthread_nonstandard_stacks;
 261
 262 /* File descriptor for sending requests to the thread manager.
 263    Initially -1, meaning that __pthread_initialize_manager must be called. */
 264
 265 extern int __pthread_manager_request;
 266
 267 /* Other end of the pipe for sending requests to the thread manager. */
 268
 269 extern int __pthread_manager_reader;
 270
 271 /* Limits of the thread manager stack. */
 272
 273 extern char *__pthread_manager_thread_bos;
 274 extern char *__pthread_manager_thread_tos;
 275
 276 /* Pending request for a process-wide exit */
 277
 278 extern int __pthread_exit_requested, __pthread_exit_code;
 279
 280 /* Set to 1 by gdb if we're debugging */
 281
 282 extern volatile int __pthread_threads_debug;
 283
 284 /* Globally enabled events.  */
 285 extern volatile td_thr_events_t __pthread_threads_events;
 286
 287 /* Pointer to descriptor of thread with last event.  */
 288 extern volatile pthread_descr __pthread_last_event;
 289
 290 /* Return the handle corresponding to a thread id */
 291
 292 static inline pthread_handle thread_handle(pthread_t id)
 293 {
 294   return &__pthread_handles[id % PTHREAD_THREADS_MAX];
 295 }
 296
 297 /* Validate a thread handle. Must have acquired h->h_spinlock before. */
 298
 299 static inline int invalid_handle(pthread_handle h, pthread_t id)
 300 {
 301   return h->h_descr == NULL || h->h_descr->p_tid != id;
 302 }
 303
 304 /* Fill in defaults left unspecified by pt-machine.h.  */
 305
 306 /* The page size we can get from the system.  This should likely not be
 307    changed by the machine file but, you never know.  */
 308 #ifndef PAGE_SIZE
 309 #define PAGE_SIZE  (sysconf (_SC_PAGE_SIZE))
 310 #endif
 311
 312 /* The max size of the thread stack segments.  If the default
 313    THREAD_SELF implementation is used, this must be a power of two and
 314    a multiple of PAGE_SIZE.  */
 315 #ifndef STACK_SIZE
 316 #define STACK_SIZE  (2 * 1024 * 1024)
 317 #endif
 318
 319 /* The initial size of the thread stack.  Must be a multiple of PAGE_SIZE.  */
 320 #ifndef INITIAL_STACK_SIZE
 321 #define INITIAL_STACK_SIZE  (4 * PAGE_SIZE)
 322 #endif
 323
 324 /* Size of the thread manager stack. The "- 32" avoids wasting space
 325    with some malloc() implementations. */
 326 #ifndef THREAD_MANAGER_STACK_SIZE
 327 #define THREAD_MANAGER_STACK_SIZE  (2 * PAGE_SIZE - 32)
 328 #endif
 329
 330 /* The base of the "array" of thread stacks.  The array will grow down from
 331    here.  Defaults to the calculated bottom of the initial application
 332    stack.  */
 333 #ifndef THREAD_STACK_START_ADDRESS
 334 #define THREAD_STACK_START_ADDRESS  __pthread_initial_thread_bos
 335 #endif
 336
 337 /* Get some notion of the current stack.  Need not be exactly the top
 338    of the stack, just something somewhere in the current frame.  */
 339 #ifndef CURRENT_STACK_FRAME
 340 #define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 341 #endif
 342
 343 /* Recover thread descriptor for the current thread */
 344
 345 extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
 346
 347 static inline pthread_descr thread_self (void) __attribute__ ((const));
 348 static inline pthread_descr thread_self (void)
 349 {
 350 #ifdef THREAD_SELF
 351   return THREAD_SELF;
 352 #else
 353   char *sp = CURRENT_STACK_FRAME;
 354   if (sp >= __pthread_initial_thread_bos)
 355     return &__pthread_initial_thread;
 356   else if (sp >= __pthread_manager_thread_bos
 357            && sp < __pthread_manager_thread_tos)
 358     return &__pthread_manager_thread;
 359   else if (__pthread_nonstandard_stacks)
 360     return __pthread_find_self();
 361   else
 362     return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
 363 #endif
 364 }
 365
 366 /* If MEMORY_BARRIER isn't defined in pt-machine.h, assume the architecture
 367    doesn't need a memory barrier instruction (e.g. Intel x86).  Some
 368    architectures distinguish between full, read and write barriers.  */
 369
 370 #ifndef MEMORY_BARRIER
 371 #define MEMORY_BARRIER()
 372 #endif
 373 #ifndef READ_MEMORY_BARRIER
 374 #define READ_MEMORY_BARRIER() MEMORY_BARRIER()
 375 #endif
 376 #ifndef WRITE_MEMORY_BARRIER
 377 #define WRITE_MEMORY_BARRIER() MEMORY_BARRIER()
 378 #endif
 379
 380 /* Max number of times we must spin on a spinlock calling sched_yield().
 381    After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
 382
 383 #ifndef MAX_SPIN_COUNT
 384 #define MAX_SPIN_COUNT 50
 385 #endif
 386
 387 /* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
 388    after MAX_SPIN_COUNT iterations of sched_yield().
 389    With the 2.0 and 2.1 kernels, this MUST BE > 2ms.
 390    (Otherwise the kernel does busy-waiting for realtime threads,
 391     giving other threads no chance to run.) */
 392
 393 #ifndef SPIN_SLEEP_DURATION
 394 #define SPIN_SLEEP_DURATION 2000001
 395 #endif
 396
 397 /* Debugging */
 398
 399 #ifdef DEBUG
 400 #include <assert.h>
 401 #define ASSERT assert
 402 #define MSG __pthread_message
 403 #else
 404 #define ASSERT(x)
 405 #define MSG(msg,arg...)
 406 #endif
 407
 408 /* Internal global functions */
 409
 410 void __pthread_destroy_specifics(void);
 411 void __pthread_perform_cleanup(void);
 412 int __pthread_initialize_manager(void);
 413 void __pthread_message(char * fmt, ...);
 414 int __pthread_manager(void *reqfd);
 415 int __pthread_manager_event(void *reqfd);
 416 void __pthread_manager_sighandler(int sig);
 417 void __pthread_reset_main_thread(void);
 418 void __pthread_once_fork_prepare(void);
 419 void __pthread_once_fork_parent(void);
 420 void __pthread_once_fork_child(void);
 421 void __flockfilelist(void);
 422 void __funlockfilelist(void);
 423 void __fresetlockfiles(void);
 424 void __pthread_manager_adjust_prio(int thread_prio);
 425 void __pthread_set_own_extricate_if(pthread_descr self, pthread_extricate_if *peif);
 426
 427 extern int __pthread_attr_setguardsize (pthread_attr_t *__attr,
 428                                         size_t __guardsize);
 429 extern int __pthread_attr_getguardsize (const pthread_attr_t *__attr,
 430                                         size_t *__guardsize);
 431 extern int __pthread_attr_setstackaddr (pthread_attr_t *__attr,
 432                                         void *__stackaddr);
 433 extern int __pthread_attr_getstackaddr (const pthread_attr_t *__attr,
 434                                         void **__stackaddr);
 435 extern int __pthread_attr_setstacksize (pthread_attr_t *__attr,
 436                                         size_t __stacksize);
 437 extern int __pthread_attr_getstacksize (const pthread_attr_t *__attr,
 438                                         size_t *__stacksize);
 439 extern int __pthread_getconcurrency (void);
 440 extern int __pthread_setconcurrency (int __level);
 441 extern int __pthread_mutexattr_gettype (const pthread_mutexattr_t *__attr,
 442                                         int *__kind);
 443 extern void __pthread_kill_other_threads_np (void);
 444
 445 void __pthread_restart_old(pthread_descr th);
 446 void __pthread_suspend_old(pthread_descr self);
 447 int __pthread_timedsuspend_old(pthread_descr self, const struct timespec *abs);
 448
 449 void __pthread_restart_new(pthread_descr th);
 450 void __pthread_suspend_new(pthread_descr self);
 451 int __pthread_timedsuspend_new(pthread_descr self, const struct timespec *abs);
 452
 453 void __pthread_wait_for_restart_signal(pthread_descr self);
 454
 455 int __pthread_yield (void);
 456
 457 /* Global pointers to old or new suspend functions */
 458
 459 extern void (*__pthread_restart)(pthread_descr);
 460 extern void (*__pthread_suspend)(pthread_descr);
 461 extern int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *);
 462
 463 /* Prototypes for the function without cancelation support when the
 464    normal version has it.  */
 465 extern int __libc_close (int fd);
 466 extern int __libc_nanosleep (const struct timespec *requested_time,
 467                              struct timespec *remaining);
 468 extern pid_t __libc_waitpid (pid_t pid, int *stat_loc, int options);
 469
 470 /* Prototypes for some of the new semaphore functions.  */
 471 extern int __new_sem_post (sem_t * sem);
 472
 473 /* The functions called the signal events.  */
 474 extern void __linuxthreads_create_event (void);
 475 extern void __linuxthreads_death_event (void);
 476 extern void __linuxthreads_reap_event (void);
 477
 478 #endif /* internals.h */