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 /* Internal data structures */
  16
  17 /* Includes */
  18
  19 #include <limits.h>
  20 #include <setjmp.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <sys/types.h>
  24 #include <bits/libc-tsd.h> /* for _LIBC_TSD_KEY_N */
  25
  26 #include "pt-machine.h"
  27 #include "semaphore.h"
  28
  29 #ifndef THREAD_GETMEM
  30 # define THREAD_GETMEM(descr, member) descr->member
  31 #endif
  32 #ifndef THREAD_GETMEM_NC
  33 # define THREAD_GETMEM_NC(descr, member) descr->member
  34 #endif
  35 #ifndef THREAD_SETMEM
  36 # define THREAD_SETMEM(descr, member, value) descr->member = (value)
  37 #endif
  38 #ifndef THREAD_SETMEM_NC
  39 # define THREAD_SETMEM_NC(descr, member, value) descr->member = (value)
  40 #endif
  41
  42 /* Arguments passed to thread creation routine */
  43
  44 struct pthread_start_args {
  45   void * (*start_routine)(void *); /* function to run */
  46   void * arg;                   /* its argument */
  47   sigset_t mask;                /* initial signal mask for thread */
  48   int schedpolicy;              /* initial scheduling policy (if any) */
  49   struct sched_param schedparam; /* initial scheduling parameters (if any) */
  50 };
  51
  52
  53 /* We keep thread specific data in a special data structure, a two-level
  54    array.  The top-level array contains pointers to dynamically allocated
  55    arrays of a certain number of data pointers.  So we can implement a
  56    sparse array.  Each dynamic second-level array has
  57         PTHREAD_KEY_2NDLEVEL_SIZE
  58    entries.  This value shouldn't be too large.  */
  59 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  60
  61 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  62    keys in each subarray.  */
  63 #define PTHREAD_KEY_1STLEVEL_SIZE \
  64   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  65    / PTHREAD_KEY_2NDLEVEL_SIZE)
  66
  67 typedef void (*destr_function)(void *);
  68
  69 struct pthread_key_struct {
  70   int in_use;                   /* already allocated? */
  71   destr_function destr;         /* destruction routine */
  72 };
  73
  74
  75 #define PTHREAD_START_ARGS_INITIALIZER(fct) \
  76   { (void *(*) (void *)) fct, NULL, {{0, }}, 0, { 0 } }
  77
  78 /* The type of thread descriptors */
  79
  80 typedef struct _pthread_descr_struct * pthread_descr;
  81
  82 struct _pthread_descr_struct {
  83   pthread_descr p_nextlive, p_prevlive;
  84                                 /* Double chaining of active threads */
  85   pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
  86   pthread_descr p_nextlock;     /* can be on a queue and waiting on a lock */
  87   pthread_t p_tid;              /* Thread identifier */
  88   int p_pid;                    /* PID of Unix process */
  89   int p_priority;               /* Thread priority (== 0 if not realtime) */
  90   struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
  91   int p_signal;                 /* last signal received */
  92   sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
  93   sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
  94   char p_terminated;            /* true if terminated e.g. by pthread_exit */
  95   char p_detached;              /* true if detached */
  96   char p_exited;                /* true if the assoc. process terminated */
  97   void * p_retval;              /* placeholder for return value */
  98   int p_retcode;                /* placeholder for return code */
  99   pthread_descr p_joining;      /* thread joining on that thread or NULL */
 100   struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
 101   char p_cancelstate;           /* cancellation state */
 102   char p_canceltype;            /* cancellation type (deferred/async) */
 103   char p_canceled;              /* cancellation request pending */
 104   int * p_errnop;               /* pointer to used errno variable */
 105   int p_errno;                  /* error returned by last system call */
 106   int * p_h_errnop;             /* pointer to used h_errno variable */
 107   int p_h_errno;                /* error returned by last netdb function */
 108   char * p_in_sighandler;       /* stack address of sighandler, or NULL */
 109   char p_sigwaiting;            /* true if a sigwait() is in progress */
 110   struct pthread_start_args p_start_args; /* arguments for thread creation */
 111   void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
 112   void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
 113   int p_userstack;              /* nonzero if the user provided the stack */
 114   void *p_guardaddr;            /* address of guard area or NULL */
 115   size_t p_guardsize;           /* size of guard area */
 116   pthread_descr p_self;         /* Pointer to this structure */
 117   int p_nr;                     /* Index of descriptor in __pthread_handles */
 118 } __attribute__ ((aligned(32))); /* We need to align the structure so that
 119                                     doubles are aligned properly.  This is 8
 120                                     bytes on MIPS and 16 bytes on MIPS64.
 121                                     32 bytes might give better cache
 122                                     utilization.  */
 123
 124
 125 /* The type of thread handles. */
 126
 127 typedef struct pthread_handle_struct * pthread_handle;
 128
 129 struct pthread_handle_struct {
 130   struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */
 131   pthread_descr h_descr;        /* Thread descriptor or NULL if invalid */
 132   char * h_bottom;              /* Lowest address in the stack thread */
 133 };
 134
 135 /* The type of messages sent to the thread manager thread */
 136
 137 struct pthread_request {
 138   pthread_descr req_thread;     /* Thread doing the request */
 139   enum {                        /* Request kind */
 140     REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT,
 141     REQ_POST, REQ_DEBUG
 142   } req_kind;
 143   union {                       /* Arguments for request */
 144     struct {                    /* For REQ_CREATE: */
 145       const pthread_attr_t * attr; /* thread attributes */
 146       void * (*fn)(void *);     /*   start function */
 147       void * arg;               /*   argument to start function */
 148       sigset_t mask;            /*   signal mask */
 149     } create;
 150     struct {                    /* For REQ_FREE: */
 151       pthread_t thread_id;      /*   identifier of thread to free */
 152     } free;
 153     struct {                    /* For REQ_PROCESS_EXIT: */
 154       int code;                 /*   exit status */
 155     } exit;
 156     void * post;                /* For REQ_POST: the semaphore */
 157   } req_args;
 158 };
 159
 160
 161 /* Signals used for suspend/restart and for cancellation notification.  */
 162
 163 extern int __pthread_sig_restart;
 164 extern int __pthread_sig_cancel;
 165
 166 /* Signal used for interfacing with gdb */
 167
 168 extern int __pthread_sig_debug;
 169
 170 /* Global array of thread handles, used for validating a thread id
 171    and retrieving the corresponding thread descriptor. Also used for
 172    mapping the available stack segments. */
 173
 174 extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX];
 175
 176 /* Descriptor of the initial thread */
 177
 178 extern struct _pthread_descr_struct __pthread_initial_thread;
 179
 180 /* Descriptor of the manager thread */
 181
 182 extern struct _pthread_descr_struct __pthread_manager_thread;
 183
 184 /* Descriptor of the main thread */
 185
 186 extern pthread_descr __pthread_main_thread;
 187
 188 /* Limit between the stack of the initial thread (above) and the
 189    stacks of other threads (below). Aligned on a STACK_SIZE boundary.
 190    Initially 0, meaning that the current thread is (by definition)
 191    the initial thread. */
 192
 193 extern char *__pthread_initial_thread_bos;
 194
 195 /* Indicate whether at least one thread has a user-defined stack (if 1),
 196    or all threads have stacks supplied by LinuxThreads (if 0). */
 197
 198 extern int __pthread_nonstandard_stacks;
 199
 200 /* File descriptor for sending requests to the thread manager.
 201    Initially -1, meaning that __pthread_initialize_manager must be called. */
 202
 203 extern int __pthread_manager_request;
 204
 205 /* Other end of the pipe for sending requests to the thread manager. */
 206
 207 extern int __pthread_manager_reader;
 208
 209 /* Limits of the thread manager stack. */
 210
 211 extern char *__pthread_manager_thread_bos;
 212 extern char *__pthread_manager_thread_tos;
 213
 214 /* Pending request for a process-wide exit */
 215
 216 extern int __pthread_exit_requested, __pthread_exit_code;
 217
 218 /* Set to 1 by gdb if we're debugging */
 219
 220 extern volatile int __pthread_threads_debug;
 221
 222 /* Return the handle corresponding to a thread id */
 223
 224 static inline pthread_handle thread_handle(pthread_t id)
 225 {
 226   return &__pthread_handles[id % PTHREAD_THREADS_MAX];
 227 }
 228
 229 /* Validate a thread handle. Must have acquired h->h_spinlock before. */
 230
 231 static inline int invalid_handle(pthread_handle h, pthread_t id)
 232 {
 233   return h->h_descr == NULL || h->h_descr->p_tid != id;
 234 }
 235
 236 /* Fill in defaults left unspecified by pt-machine.h.  */
 237
 238 /* The page size we can get from the system.  This should likely not be
 239    changed by the machine file but, you never know.  */
 240 #ifndef PAGE_SIZE
 241 #define PAGE_SIZE  (sysconf (_SC_PAGE_SIZE))
 242 #endif
 243
 244 /* The max size of the thread stack segments.  If the default
 245    THREAD_SELF implementation is used, this must be a power of two and
 246    a multiple of PAGE_SIZE.  */
 247 #ifndef STACK_SIZE
 248 #define STACK_SIZE  (2 * 1024 * 1024)
 249 #endif
 250
 251 /* The initial size of the thread stack.  Must be a multiple of PAGE_SIZE.  */
 252 #ifndef INITIAL_STACK_SIZE
 253 #define INITIAL_STACK_SIZE  (4 * PAGE_SIZE)
 254 #endif
 255
 256 /* Size of the thread manager stack. The "- 32" avoids wasting space
 257    with some malloc() implementations. */
 258 #ifndef THREAD_MANAGER_STACK_SIZE
 259 #define THREAD_MANAGER_STACK_SIZE  (2 * PAGE_SIZE - 32)
 260 #endif
 261
 262 /* The base of the "array" of thread stacks.  The array will grow down from
 263    here.  Defaults to the calculated bottom of the initial application
 264    stack.  */
 265 #ifndef THREAD_STACK_START_ADDRESS
 266 #define THREAD_STACK_START_ADDRESS  __pthread_initial_thread_bos
 267 #endif
 268
 269 /* Get some notion of the current stack.  Need not be exactly the top
 270    of the stack, just something somewhere in the current frame.  */
 271 #ifndef CURRENT_STACK_FRAME
 272 #define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 273 #endif
 274
 275 /* Recover thread descriptor for the current thread */
 276
 277 extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
 278
 279 static inline pthread_descr thread_self (void) __attribute__ ((const));
 280 static inline pthread_descr thread_self (void)
 281 {
 282 #ifdef THREAD_SELF
 283   return THREAD_SELF;
 284 #else
 285   char *sp = CURRENT_STACK_FRAME;
 286   if (sp >= __pthread_initial_thread_bos)
 287     return &__pthread_initial_thread;
 288   else if (sp >= __pthread_manager_thread_bos
 289            && sp < __pthread_manager_thread_tos)
 290     return &__pthread_manager_thread;
 291   else if (__pthread_nonstandard_stacks)
 292     return __pthread_find_self();
 293   else
 294     return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
 295 #endif
 296 }
 297
 298 /* Max number of times we must spin on a spinlock calling sched_yield().
 299    After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
 300
 301 #ifndef MAX_SPIN_COUNT
 302 #define MAX_SPIN_COUNT 50
 303 #endif
 304
 305 /* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
 306    after MAX_SPIN_COUNT iterations of sched_yield().
 307    With the 2.0 and 2.1 kernels, this MUST BE > 2ms.
 308    (Otherwise the kernel does busy-waiting for realtime threads,
 309     giving other threads no chance to run.) */
 310
 311 #ifndef SPIN_SLEEP_DURATION
 312 #define SPIN_SLEEP_DURATION 2000001
 313 #endif
 314
 315 /* Debugging */
 316
 317 #ifdef DEBUG
 318 #include <assert.h>
 319 #define ASSERT assert
 320 #define MSG __pthread_message
 321 #else
 322 #define ASSERT(x)
 323 #define MSG(msg,arg...)
 324 #endif
 325
 326 /* Internal global functions */
 327
 328 void __pthread_destroy_specifics(void);
 329 void __pthread_perform_cleanup(void);
 330 int __pthread_initialize_manager(void);
 331 void __pthread_message(char * fmt, ...);
 332 int __pthread_manager(void *reqfd);
 333 void __pthread_manager_sighandler(int sig);
 334 void __pthread_reset_main_thread(void);
 335 void __fresetlockfiles(void);
 336 void __pthread_manager_adjust_prio(int thread_prio);
 337
 338 extern int __pthread_attr_setguardsize __P ((pthread_attr_t *__attr,
 339                                              size_t __guardsize));
 340 extern int __pthread_attr_getguardsize __P ((__const pthread_attr_t *__attr,
 341                                              size_t *__guardsize));
 342 extern int __pthread_attr_setstackaddr __P ((pthread_attr_t *__attr,
 343                                              void *__stackaddr));
 344 extern int __pthread_attr_getstackaddr __P ((__const pthread_attr_t *__attr,
 345                                              void **__stackaddr));
 346 extern int __pthread_attr_setstacksize __P ((pthread_attr_t *__attr,
 347                                              size_t __stacksize));
 348 extern int __pthread_attr_getstacksize __P ((__const pthread_attr_t *__attr,
 349                                              size_t *__stacksize));
 350 extern int __pthread_getconcurrency __P ((void));
 351 extern int __pthread_setconcurrency __P ((int __level));
 352 extern int __pthread_mutexattr_gettype __P ((__const pthread_mutexattr_t *__attr,
 353                                              int *__kind));
 354 extern void __pthread_kill_other_threads_np __P ((void));
 355
 356 /* Prototypes for the function without cancelation support when the
 357    normal version has it.  */
 358 extern int __libc_close (int fd);
 359 extern int __libc_nanosleep (const struct timespec *requested_time,
 360                              struct timespec *remaining);
 361 extern ssize_t __libc_read (int fd, void *buf, size_t count);
 362 extern pid_t __libc_waitpid (pid_t pid, int *stat_loc, int options);
 363 extern ssize_t __libc_write (int fd, const void *buf, size_t count);
 364
 365 /* Prototypes for some of the new semaphore functions.  */
 366 extern int __new_sem_post (sem_t * sem);