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