/* Linuxthreads - a simple clone()-based implementation of Posix */ /* threads for Linux. */ /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ /* */ /* This program is free software; you can redistribute it and/or */ /* modify it under the terms of the GNU Library General Public License */ /* as published by the Free Software Foundation; either version 2 */ /* of the License, or (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ /* GNU Library General Public License for more details. */ /* Internal data structures */ /* Includes */ #include /* for _LIBC_TSD_KEY_N */ #include #include #include #include #include "pt-machine.h" /* Arguments passed to thread creation routine */ struct pthread_start_args { void * (*start_routine)(void *); /* function to run */ void * arg; /* its argument */ sigset_t mask; /* initial signal mask for thread */ int schedpolicy; /* initial scheduling policy (if any) */ struct sched_param schedparam; /* initial scheduling parameters (if any) */ }; /* We keep thread specific data in a special data structure, a two-level array. The top-level array contains pointers to dynamically allocated arrays of a certain number of data pointers. So we can implement a sparse array. Each dynamic second-level array has PTHREAD_KEY_2NDLEVEL_SIZE entries. This value shouldn't be too large. */ #define PTHREAD_KEY_2NDLEVEL_SIZE 32 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE keys in each subarray. */ #define PTHREAD_KEY_1STLEVEL_SIZE \ ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \ / PTHREAD_KEY_2NDLEVEL_SIZE) #define PTHREAD_START_ARGS_INITIALIZER { NULL, NULL, {{0, }}, 0, { 0 } } /* The type of thread descriptors */ typedef struct _pthread_descr_struct * pthread_descr; struct _pthread_descr_struct { pthread_descr p_nextlive, p_prevlive; /* Double chaining of active threads */ pthread_descr p_nextwaiting; /* Next element in the queue holding the thr */ pthread_t p_tid; /* Thread identifier */ int p_pid; /* PID of Unix process */ int p_priority; /* Thread priority (== 0 if not realtime) */ struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */ int p_signal; /* last signal received */ sigjmp_buf * p_signal_jmp; /* where to siglongjmp on a signal or NULL */ sigjmp_buf * p_cancel_jmp; /* where to siglongjmp on a cancel or NULL */ char p_terminated; /* true if terminated e.g. by pthread_exit */ char p_detached; /* true if detached */ char p_exited; /* true if the assoc. process terminated */ void * p_retval; /* placeholder for return value */ int p_retcode; /* placeholder for return code */ pthread_descr p_joining; /* thread joining on that thread or NULL */ struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */ char p_cancelstate; /* cancellation state */ char p_canceltype; /* cancellation type (deferred/async) */ char p_canceled; /* cancellation request pending */ int * p_errnop; /* pointer to used errno variable */ int p_errno; /* error returned by last system call */ int * p_h_errnop; /* pointer to used h_errno variable */ int p_h_errno; /* error returned by last netdb function */ char * p_in_sighandler; /* stack address of sighandler, or NULL */ char p_sigwaiting; /* true if a sigwait() is in progress */ struct pthread_start_args p_start_args; /* arguments for thread creation */ void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */ void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */ int p_userstack; /* nonzero if the user provided the stack */ void *p_guardaddr; /* address of guard area or NULL */ size_t p_guardsize; /* size of guard area */ }; /* The type of thread handles. */ typedef struct pthread_handle_struct * pthread_handle; struct pthread_handle_struct { struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */ pthread_descr h_descr; /* Thread descriptor or NULL if invalid */ char * h_bottom; /* Lowest address in the stack thread */ }; /* The type of messages sent to the thread manager thread */ struct pthread_request { pthread_descr req_thread; /* Thread doing the request */ enum { /* Request kind */ REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT, REQ_POST, REQ_DEBUG } req_kind; union { /* Arguments for request */ struct { /* For REQ_CREATE: */ const pthread_attr_t * attr; /* thread attributes */ void * (*fn)(void *); /* start function */ void * arg; /* argument to start function */ sigset_t mask; /* signal mask */ } create; struct { /* For REQ_FREE: */ pthread_t thread_id; /* identifier of thread to free */ } free; struct { /* For REQ_PROCESS_EXIT: */ int code; /* exit status */ } exit; void * post; /* For REQ_POST: the semaphore */ } req_args; }; /* Signals used for suspend/restart and for cancellation notification. */ #ifdef SIGRTMIN /* The have real-time signals. */ extern int __pthread_sig_restart; extern int __pthread_sig_cancel; # define PTHREAD_SIG_RESTART __pthread_sig_restart # define PTHREAD_SIG_CANCEL __pthread_sig_cancel #else # define PTHREAD_SIG_RESTART SIGUSR1 # define PTHREAD_SIG_CANCEL SIGUSR2 #endif /* Global array of thread handles, used for validating a thread id and retrieving the corresponding thread descriptor. Also used for mapping the available stack segments. */ extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX]; /* Descriptor of the initial thread */ extern struct _pthread_descr_struct __pthread_initial_thread; /* Descriptor of the manager thread */ extern struct _pthread_descr_struct __pthread_manager_thread; /* Descriptor of the main thread */ extern pthread_descr __pthread_main_thread; /* Limit between the stack of the initial thread (above) and the stacks of other threads (below). Aligned on a STACK_SIZE boundary. Initially 0, meaning that the current thread is (by definition) the initial thread. */ extern char *__pthread_initial_thread_bos; /* Indicate whether at least one thread has a user-defined stack (if 1), or all threads have stacks supplied by LinuxThreads (if 0). */ extern int __pthread_nonstandard_stacks; /* File descriptor for sending requests to the thread manager. Initially -1, meaning that __pthread_initialize_manager must be called. */ extern int __pthread_manager_request; /* Other end of the pipe for sending requests to the thread manager. */ extern int __pthread_manager_reader; /* Limits of the thread manager stack. */ extern char *__pthread_manager_thread_bos; extern char *__pthread_manager_thread_tos; /* Pending request for a process-wide exit */ extern int __pthread_exit_requested, __pthread_exit_code; /* Set to 1 by gdb if we're debugging */ extern volatile int __pthread_threads_debug; /* Return the handle corresponding to a thread id */ static inline pthread_handle thread_handle(pthread_t id) { return &__pthread_handles[id % PTHREAD_THREADS_MAX]; } /* Validate a thread handle. Must have acquired h->h_spinlock before. */ static inline int invalid_handle(pthread_handle h, pthread_t id) { return h->h_descr == NULL || h->h_descr->p_tid != id; } /* Fill in defaults left unspecified by pt-machine.h. */ /* The page size we can get from the system. This should likely not be changed by the machine file but, you never know. */ #ifndef PAGE_SIZE #define PAGE_SIZE (sysconf (_SC_PAGE_SIZE)) #endif /* The max size of the thread stack segments. If the default THREAD_SELF implementation is used, this must be a power of two and a multiple of PAGE_SIZE. */ #ifndef STACK_SIZE #define STACK_SIZE (2 * 1024 * 1024) #endif /* The initial size of the thread stack. Must be a multiple of PAGE_SIZE. */ #ifndef INITIAL_STACK_SIZE #define INITIAL_STACK_SIZE (4 * PAGE_SIZE) #endif /* Size of the thread manager stack. The "- 32" avoids wasting space with some malloc() implementations. */ #ifndef THREAD_MANAGER_STACK_SIZE #define THREAD_MANAGER_STACK_SIZE (2 * PAGE_SIZE - 32) #endif /* The base of the "array" of thread stacks. The array will grow down from here. Defaults to the calculated bottom of the initial application stack. */ #ifndef THREAD_STACK_START_ADDRESS #define THREAD_STACK_START_ADDRESS __pthread_initial_thread_bos #endif /* Get some notion of the current stack. Need not be exactly the top of the stack, just something somewhere in the current frame. */ #ifndef CURRENT_STACK_FRAME #define CURRENT_STACK_FRAME ({ char __csf; &__csf; }) #endif /* Recover thread descriptor for the current thread */ extern pthread_descr __pthread_find_self (void) __attribute__ ((const)); static inline pthread_descr thread_self (void) __attribute__ ((const)); static inline pthread_descr thread_self (void) { #ifdef THREAD_SELF return THREAD_SELF; #else char *sp = CURRENT_STACK_FRAME; if (sp >= __pthread_initial_thread_bos) return &__pthread_initial_thread; else if (sp >= __pthread_manager_thread_bos && sp < __pthread_manager_thread_tos) return &__pthread_manager_thread; else if (__pthread_nonstandard_stacks) return __pthread_find_self(); else return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1; #endif } /* Max number of times we must spin on a spinlock calling sched_yield(). After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */ #ifndef MAX_SPIN_COUNT #define MAX_SPIN_COUNT 50 #endif /* Duration of sleep (in nanoseconds) when we can't acquire a spinlock after MAX_SPIN_COUNT iterations of sched_yield(). With the 2.0 and 2.1 kernels, this MUST BE > 2ms. (Otherwise the kernel does busy-waiting for realtime threads, giving other threads no chance to run.) */ #ifndef SPIN_SLEEP_DURATION #define SPIN_SLEEP_DURATION 2000001 #endif /* Debugging */ #ifdef DEBUG #include #define ASSERT assert #define MSG __pthread_message #else #define ASSERT(x) #define MSG(msg,arg...) #endif /* Internal global functions */ void __pthread_destroy_specifics(void); void __pthread_perform_cleanup(void); int __pthread_initialize_manager(void); void __pthread_message(char * fmt, ...); int __pthread_manager(void *reqfd); void __pthread_manager_sighandler(int sig); void __pthread_reset_main_thread(void); void __fresetlockfiles(void); void __pthread_manager_adjust_prio(int thread_prio); /* Prototypes for the function without cancelation support when the normal version has it. */ extern int __libc_close (int fd); extern int __libc_nanosleep (const struct timespec *requested_time, struct timespec *remaining); extern int __libc_read (int fd, void *buf, size_t count); extern pid_t __libc_waitpid (pid_t pid, int *stat_loc, int options); extern int __libc_write (int fd, const void *buf, size_t count);