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