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-lock.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 /* Arguments passed to thread creation routine */
  29
  30 struct pthread_start_args {
  31   void * (*start_routine)(void *); /* function to run */
  32   void * arg;                   /* its argument */
  33   sigset_t mask;                /* initial signal mask for thread */
  34   int schedpolicy;              /* initial scheduling policy (if any) */
  35   struct sched_param schedparam; /* initial scheduling parameters (if any) */
  36 };
  37
  38
  39 /* We keep thread specific data in a special data structure, a two-level
  40    array.  The top-level array contains pointers to dynamically allocated
  41    arrays of a certain number of data pointers.  So we can implement a
  42    sparse array.  Each dynamic second-level array has
  43         PTHREAD_KEY_2NDLEVEL_SIZE
  44    entries.  This value shouldn't be too large.  */
  45 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  46
  47 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  48    keys in each subarray.  */
  49 #define PTHREAD_KEY_1STLEVEL_SIZE \
  50   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  51    / PTHREAD_KEY_2NDLEVEL_SIZE)
  52
  53
  54 #define PTHREAD_START_ARGS_INITIALIZER { NULL, NULL, {{0, }}, 0, { 0 } }
  55
  56 /* The type of thread descriptors */
  57
  58 typedef struct _pthread_descr_struct * pthread_descr;
  59
  60 struct _pthread_descr_struct {
  61   pthread_descr p_nextlive, p_prevlive;
  62                                 /* Double chaining of active threads */
  63   pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
  64   pthread_t p_tid;              /* Thread identifier */
  65   int p_pid;                    /* PID of Unix process */
  66   int p_priority;               /* Thread priority (== 0 if not realtime) */
  67   struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
  68   int p_signal;                 /* last signal received */
  69   sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
  70   sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
  71   char p_terminated;            /* true if terminated e.g. by pthread_exit */
  72   char p_detached;              /* true if detached */
  73   char p_exited;                /* true if the assoc. process terminated */
  74   void * p_retval;              /* placeholder for return value */
  75   int p_retcode;                /* placeholder for return code */
  76   pthread_descr p_joining;      /* thread joining on that thread or NULL */
  77   struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
  78   char p_cancelstate;           /* cancellation state */
  79   char p_canceltype;            /* cancellation type (deferred/async) */
  80   char p_canceled;              /* cancellation request pending */
  81   int * p_errnop;               /* pointer to used errno variable */
  82   int p_errno;                  /* error returned by last system call */
  83   int * p_h_errnop;             /* pointer to used h_errno variable */
  84   int p_h_errno;                /* error returned by last netdb function */
  85   char * p_in_sighandler;       /* stack address of sighandler, or NULL */
  86   char p_sigwaiting;            /* true if a sigwait() is in progress */
  87   struct pthread_start_args p_start_args; /* arguments for thread creation */
  88   void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
  89   void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
  90   int p_userstack;              /* nonzero if the user provided the stack */
  91   void *p_guardaddr;            /* address of guard area or NULL */
  92   size_t p_guardsize;           /* size of guard area */
  93 };
  94
  95 /* The type of thread handles. */
  96
  97 typedef struct pthread_handle_struct * pthread_handle;
  98
  99 struct pthread_handle_struct {
 100   struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */
 101   pthread_descr h_descr;        /* Thread descriptor or NULL if invalid */
 102   char * h_bottom;              /* Lowest address in the stack thread */
 103 };
 104
 105 /* The type of messages sent to the thread manager thread */
 106
 107 struct pthread_request {
 108   pthread_descr req_thread;     /* Thread doing the request */
 109   enum {                        /* Request kind */
 110     REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT,
 111     REQ_POST, REQ_DEBUG
 112   } req_kind;
 113   union {                       /* Arguments for request */
 114     struct {                    /* For REQ_CREATE: */
 115       const pthread_attr_t * attr; /* thread attributes */
 116       void * (*fn)(void *);     /*   start function */
 117       void * arg;               /*   argument to start function */
 118       sigset_t mask;            /*   signal mask */
 119     } create;
 120     struct {                    /* For REQ_FREE: */
 121       pthread_t thread_id;      /*   identifier of thread to free */
 122     } free;
 123     struct {                    /* For REQ_PROCESS_EXIT: */
 124       int code;                 /*   exit status */
 125     } exit;
 126     void * post;                /* For REQ_POST: the semaphore */
 127   } req_args;
 128 };
 129
 130
 131 /* Signals used for suspend/restart and for cancellation notification.  */
 132
 133 #ifdef SIGRTMIN
 134 /* The have real-time signals.  */
 135 extern int __pthread_sig_restart;
 136 extern int __pthread_sig_cancel;
 137 # define PTHREAD_SIG_RESTART __pthread_sig_restart
 138 # define PTHREAD_SIG_CANCEL __pthread_sig_cancel
 139 #else
 140 # define PTHREAD_SIG_RESTART SIGUSR1
 141 # define PTHREAD_SIG_CANCEL SIGUSR2
 142 #endif
 143
 144 /* Global array of thread handles, used for validating a thread id
 145    and retrieving the corresponding thread descriptor. Also used for
 146    mapping the available stack segments. */
 147
 148 extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX];
 149
 150 /* Descriptor of the initial thread */
 151
 152 extern struct _pthread_descr_struct __pthread_initial_thread;
 153
 154 /* Descriptor of the manager thread */
 155
 156 extern struct _pthread_descr_struct __pthread_manager_thread;
 157
 158 /* Descriptor of the main thread */
 159
 160 extern pthread_descr __pthread_main_thread;
 161
 162 /* Limit between the stack of the initial thread (above) and the
 163    stacks of other threads (below). Aligned on a STACK_SIZE boundary.
 164    Initially 0, meaning that the current thread is (by definition)
 165    the initial thread. */
 166
 167 extern char *__pthread_initial_thread_bos;
 168
 169 /* Indicate whether at least one thread has a user-defined stack (if 1),
 170    or all threads have stacks supplied by LinuxThreads (if 0). */
 171
 172 extern int __pthread_nonstandard_stacks;
 173
 174 /* File descriptor for sending requests to the thread manager.
 175    Initially -1, meaning that __pthread_initialize_manager must be called. */
 176
 177 extern int __pthread_manager_request;
 178
 179 /* Other end of the pipe for sending requests to the thread manager. */
 180
 181 extern int __pthread_manager_reader;
 182
 183 /* Limits of the thread manager stack. */
 184
 185 extern char *__pthread_manager_thread_bos;
 186 extern char *__pthread_manager_thread_tos;
 187
 188 /* Pending request for a process-wide exit */
 189
 190 extern int __pthread_exit_requested, __pthread_exit_code;
 191
 192 /* Set to 1 by gdb if we're debugging */
 193
 194 extern volatile int __pthread_threads_debug;
 195
 196 /* Return the handle corresponding to a thread id */
 197
 198 static inline pthread_handle thread_handle(pthread_t id)
 199 {
 200   return &__pthread_handles[id % PTHREAD_THREADS_MAX];
 201 }
 202
 203 /* Validate a thread handle. Must have acquired h->h_spinlock before. */
 204
 205 static inline int invalid_handle(pthread_handle h, pthread_t id)
 206 {
 207   return h->h_descr == NULL || h->h_descr->p_tid != id;
 208 }
 209
 210 /* Fill in defaults left unspecified by pt-machine.h.  */
 211
 212 /* The page size we can get from the system.  This should likely not be
 213    changed by the machine file but, you never know.  */
 214 #ifndef PAGE_SIZE
 215 #define PAGE_SIZE  (sysconf (_SC_PAGE_SIZE))
 216 #endif
 217
 218 /* The max size of the thread stack segments.  If the default
 219    THREAD_SELF implementation is used, this must be a power of two and
 220    a multiple of PAGE_SIZE.  */
 221 #ifndef STACK_SIZE
 222 #define STACK_SIZE  (2 * 1024 * 1024)
 223 #endif
 224
 225 /* The initial size of the thread stack.  Must be a multiple of PAGE_SIZE.  */
 226 #ifndef INITIAL_STACK_SIZE
 227 #define INITIAL_STACK_SIZE  (4 * PAGE_SIZE)
 228 #endif
 229
 230 /* Size of the thread manager stack. The "- 32" avoids wasting space
 231    with some malloc() implementations. */
 232 #ifndef THREAD_MANAGER_STACK_SIZE
 233 #define THREAD_MANAGER_STACK_SIZE  (2 * PAGE_SIZE - 32)
 234 #endif
 235
 236 /* The base of the "array" of thread stacks.  The array will grow down from
 237    here.  Defaults to the calculated bottom of the initial application
 238    stack.  */
 239 #ifndef THREAD_STACK_START_ADDRESS
 240 #define THREAD_STACK_START_ADDRESS  __pthread_initial_thread_bos
 241 #endif
 242
 243 /* Get some notion of the current stack.  Need not be exactly the top
 244    of the stack, just something somewhere in the current frame.  */
 245 #ifndef CURRENT_STACK_FRAME
 246 #define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 247 #endif
 248
 249 /* Recover thread descriptor for the current thread */
 250
 251 extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
 252
 253 static inline pthread_descr thread_self (void) __attribute__ ((const));
 254 static inline pthread_descr thread_self (void)
 255 {
 256 #ifdef THREAD_SELF
 257   return THREAD_SELF;
 258 #else
 259   char *sp = CURRENT_STACK_FRAME;
 260   if (sp >= __pthread_initial_thread_bos)
 261     return &__pthread_initial_thread;
 262   else if (sp >= __pthread_manager_thread_bos
 263            && sp < __pthread_manager_thread_tos)
 264     return &__pthread_manager_thread;
 265   else if (__pthread_nonstandard_stacks)
 266     return __pthread_find_self();
 267   else
 268     return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
 269 #endif
 270 }
 271
 272 /* Max number of times we must spin on a spinlock calling sched_yield().
 273    After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
 274
 275 #ifndef MAX_SPIN_COUNT
 276 #define MAX_SPIN_COUNT 50
 277 #endif
 278
 279 /* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
 280    after MAX_SPIN_COUNT iterations of sched_yield().
 281    With the 2.0 and 2.1 kernels, this MUST BE > 2ms.
 282    (Otherwise the kernel does busy-waiting for realtime threads,
 283     giving other threads no chance to run.) */
 284
 285 #ifndef SPIN_SLEEP_DURATION
 286 #define SPIN_SLEEP_DURATION 2000001
 287 #endif
 288
 289 /* Debugging */
 290
 291 #ifdef DEBUG
 292 #include <assert.h>
 293 #define ASSERT assert
 294 #define MSG __pthread_message
 295 #else
 296 #define ASSERT(x)
 297 #define MSG(msg,arg...)
 298 #endif
 299
 300 /* Internal global functions */
 301
 302 void __pthread_destroy_specifics(void);
 303 void __pthread_perform_cleanup(void);
 304 int __pthread_initialize_manager(void);
 305 void __pthread_message(char * fmt, ...);
 306 int __pthread_manager(void *reqfd);
 307 void __pthread_manager_sighandler(int sig);
 308 void __pthread_reset_main_thread(void);
 309 void __fresetlockfiles(void);
 310 void __pthread_manager_adjust_prio(int thread_prio);
 311
 312 /* Prototypes for the function without cancelation support when the
 313    normal version has it.  */
 314 extern int __libc_close (int fd);
 315 extern int __libc_nanosleep (const struct timespec *requested_time,
 316                              struct timespec *remaining);
 317 extern int __libc_read (int fd, void *buf, size_t count);
 318 extern pid_t __libc_waitpid (pid_t pid, int *stat_loc, int options);
 319 extern int __libc_write (int fd, const void *buf, size_t count);