diff options
Diffstat (limited to 'src/lib/libc')
| -rw-r--r-- | src/lib/libc/include/thread_private.h | 226 |
1 files changed, 91 insertions, 135 deletions
diff --git a/src/lib/libc/include/thread_private.h b/src/lib/libc/include/thread_private.h index 0027468269..b2677fad0e 100644 --- a/src/lib/libc/include/thread_private.h +++ b/src/lib/libc/include/thread_private.h | |||
| @@ -1,179 +1,135 @@ | |||
| 1 | /* | 1 | /* $OpenBSD: thread_private.h,v 1.3 2000/01/06 07:47:09 d Exp $ */ |
| 2 | * | ||
| 3 | * Support for thread-safety in libc and libc_r common code using macros | ||
| 4 | * to declare thread-safe data structures. | ||
| 5 | * | ||
| 6 | * $OpenBSD: thread_private.h,v 1.2 1999/01/06 05:19:32 d Exp $ | ||
| 7 | */ | ||
| 8 | 2 | ||
| 9 | #ifndef _THREAD_PRIVATE_H_ | 3 | #ifndef _THREAD_PRIVATE_H_ |
| 10 | #define _THREAD_PRIVATE_H_ | 4 | #define _THREAD_PRIVATE_H_ |
| 11 | 5 | ||
| 12 | /* | 6 | #include <pthread.h> |
| 13 | * Parts of this file are | ||
| 14 | * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>. | ||
| 15 | * All rights reserved. | ||
| 16 | * | ||
| 17 | * $Id: thread_private.h,v 1.2 1999/01/06 05:19:32 d Exp $ | ||
| 18 | * $OpenBSD: thread_private.h,v 1.2 1999/01/06 05:19:32 d Exp $ | ||
| 19 | */ | ||
| 20 | 7 | ||
| 21 | /* | 8 | /* |
| 22 | * This global flag is non-zero when a process has created one | 9 | * This variable is initally 0 when there is exactly one thread. |
| 23 | * or more threads. It is used to avoid calling locking functions | 10 | * It should never decrease. |
| 24 | * when they are not required. In libc, this is always assumed | ||
| 25 | * to be zero. | ||
| 26 | */ | 11 | */ |
| 27 | 12 | extern int __isthreaded; | |
| 28 | extern volatile int __isthreaded; | ||
| 29 | |||
| 30 | #ifdef _THREAD_SAFE | ||
| 31 | |||
| 32 | #include <pthread.h> | ||
| 33 | #include "pthread_private.h" | ||
| 34 | 13 | ||
| 35 | /* | 14 | /* |
| 36 | * File lock contention is difficult to diagnose without knowing | 15 | * Weak symbols are used in libc so that the thread library can |
| 37 | * where locks were set. Allow a debug library to be built which | 16 | * efficiently wrap libc functions. |
| 38 | * records the source file and line number of each lock call. | 17 | * |
| 18 | * Use WEAK_NAME(n) to get a libc-private name for n (_weak_n), | ||
| 19 | * WEAK_ALIAS(n) to generate the weak symbol n pointing to _weak_n, | ||
| 20 | * WEAK_PROTOTYPE(n) to generate a prototype for _weak_n (based on n). | ||
| 21 | * | ||
| 22 | * If the symbol _NO_WEAK_ALIASES is defined, then symbols will be | ||
| 39 | */ | 23 | */ |
| 40 | #ifdef _FLOCK_DEBUG | 24 | |
| 41 | #define _FLOCKFILE(x) _flockfile_debug(x, __FILE__, __LINE__) | 25 | #ifdef _NO_WEAK_ALIASES |
| 26 | #defined _THREAD_SAFE | ||
| 27 | #define WEAK_NAME(name) __CONCAT(_weak,name) | ||
| 28 | #else | ||
| 29 | #define WEAK_NAME(name) name | ||
| 30 | #endif | ||
| 31 | #define WEAK_ALIAS(name) /* unavailable */ | ||
| 32 | #define WEAK_PROTOTYPE(name) /* unnecessary */ | ||
| 33 | #else /* !_NO_WEAK_AILASES */ | ||
| 34 | #define WEAK_NAME(name) __CONCAT(_weak_,name) | ||
| 35 | #define WEAK_ALIAS(name) __weak_alias(name, WEAK_NAME(name)) | ||
| 36 | #ifdef __GNUC__ | ||
| 37 | #define WEAK_PROTOTYPE(name) __typeof__(name) WEAK_NAME(name) | ||
| 42 | #else | 38 | #else |
| 43 | #define _FLOCKFILE(x) flockfile(x) | 39 | #define WEAK_PROTOTYPE(name) /* typeof() only in gcc */ |
| 44 | #endif | 40 | #endif |
| 41 | #endif /* !_NO_WEAK_ALIASES */ | ||
| 45 | 42 | ||
| 46 | /* | 43 | /* |
| 47 | * These macros help in making persistent storage thread-specific. | 44 | * These macros help in making persistent storage thread-specific. |
| 48 | * Libc makes extensive use of private static data structures | 45 | * Libc makes extensive use of private static data structures |
| 49 | * that hold state across function invocation, and these macros | 46 | * that hold state across function invocation, and these macros |
| 50 | * are no-ops when _THREAD_SAFE is not defined. | 47 | * are no-ops when running single-threaded. |
| 51 | * In a thread-safe library, the static variables are used only for | 48 | * |
| 52 | * initialising the per-thread instances of the state variables. | 49 | * Linking against the user-thread library causes these macros to |
| 50 | * allocate storage on a per-thread basis. | ||
| 53 | */ | 51 | */ |
| 52 | |||
| 53 | #define __THREAD_MUTEX_NAME(name) __CONCAT(_libc_storage_mutex_,name) | ||
| 54 | #define __THREAD_KEY_NAME(name) __CONCAT(_libc_storage_key_,name) | ||
| 54 | 55 | ||
| 55 | /* | 56 | struct _thread_private_key_struct { |
| 56 | * Give names to the private variables used to hold per-thread | 57 | pthread_once_t once; |
| 57 | * data structures. | 58 | void (*cleanfn)__P((void *)); |
| 58 | */ | 59 | pthread_key_t key; |
| 59 | #ifdef __STDC__ | 60 | }; |
| 60 | #define __THREAD_MUTEXP_NAME(name) _thread_mutexp_inst__ ## name | ||
| 61 | #define __THREAD_MUTEX_NAME(name) _thread_mutex_inst__ ## name | ||
| 62 | #define __THREAD_KEY_NAME(name) _thread_key_inst__ ## name | ||
| 63 | #else | ||
| 64 | #define __THREAD_MUTEXP_NAME(name) _thread_mutexp_inst__/**/name | ||
| 65 | #define __THREAD_MUTEX_NAME(name) _thread_mutex_inst__/**/name | ||
| 66 | #define __THREAD_KEY_NAME(name) _thread_key_inst__/**/name | ||
| 67 | #endif | ||
| 68 | 61 | ||
| 69 | /* | 62 | void _libc_private_storage_lock(pthread_mutex_t *); |
| 70 | * Mutex declare, lock and unlock macros. | 63 | void _libc_private_storage_unlock(pthread_mutex_t *); |
| 71 | */ | 64 | void * _libc_private_storage(volatile struct _thread_private_key_struct *, |
| 65 | void *, size_t, void *); | ||
| 66 | |||
| 67 | /* Declare a module mutex. */ | ||
| 72 | #define _THREAD_PRIVATE_MUTEX(name) \ | 68 | #define _THREAD_PRIVATE_MUTEX(name) \ |
| 73 | static struct pthread_mutex __THREAD_MUTEXP_NAME(name) = \ | ||
| 74 | PTHREAD_MUTEX_STATIC_INITIALIZER; \ | ||
| 75 | static pthread_mutex_t __THREAD_MUTEX_NAME(name) = \ | 69 | static pthread_mutex_t __THREAD_MUTEX_NAME(name) = \ |
| 76 | &__THREAD_MUTEXP_NAME(name); | 70 | PTHREAD_MUTEX_INITIALIZER |
| 77 | 71 | ||
| 72 | /* Lock a module mutex against use by any other threads. */ | ||
| 78 | #define _THREAD_PRIVATE_MUTEX_LOCK(name) \ | 73 | #define _THREAD_PRIVATE_MUTEX_LOCK(name) \ |
| 79 | pthread_mutex_lock(&__THREAD_MUTEX_NAME(name)) | 74 | _libc_private_storage_lock(&__THREAD_MUTEX_NAME(name)) |
| 80 | 75 | ||
| 76 | /* Unlock a module mutex. */ | ||
| 81 | #define _THREAD_PRIVATE_MUTEX_UNLOCK(name) \ | 77 | #define _THREAD_PRIVATE_MUTEX_UNLOCK(name) \ |
| 82 | pthread_mutex_unlock(&__THREAD_MUTEX_NAME(name)) | 78 | _libc_private_storage_unlock(&__THREAD_MUTEX_NAME(name)) |
| 83 | 79 | ||
| 84 | /* | 80 | /* Declare a thread-private storage key. */ |
| 85 | * A mutexed data structure used to hold the persistent state's key. | ||
| 86 | */ | ||
| 87 | struct _thread_private_key_struct { | ||
| 88 | struct pthread_mutex lockd; | ||
| 89 | pthread_mutex_t lock; | ||
| 90 | int init; | ||
| 91 | pthread_key_t key; | ||
| 92 | }; | ||
| 93 | |||
| 94 | /* | ||
| 95 | * Declaration of a per-thread state key. | ||
| 96 | */ | ||
| 97 | #define _THREAD_PRIVATE_KEY(name) \ | 81 | #define _THREAD_PRIVATE_KEY(name) \ |
| 98 | static volatile struct _thread_private_key_struct \ | 82 | static volatile struct _thread_private_key_struct \ |
| 99 | __THREAD_KEY_NAME(name) = { \ | 83 | __THREAD_KEY_NAME(name) = { \ |
| 100 | PTHREAD_MUTEX_STATIC_INITIALIZER, \ | 84 | PTHREAD_ONCE_INIT, \ |
| 101 | &__THREAD_KEY_NAME(name).lockd, \ | ||
| 102 | 0 \ | 85 | 0 \ |
| 103 | }; | 86 | } |
| 104 | 87 | ||
| 105 | /* | 88 | /* |
| 106 | * Initialisation of storage space for a per-thread state variable. | 89 | * In threaded mode, return a pointer to thread-private memory of |
| 107 | * A pointer to a per-thread *copy* of the _initv parameter is returned. | 90 | * the same size as, and (initially) with the same contents as 'storage'. If |
| 108 | * It calls malloc the first time and the space is automatically free'd | 91 | * an error occurs, the 'error' parameter is returned. |
| 109 | * when the thread dies. If you need something a bit more complicated | 92 | * In single-threaded mode, no storage is allocated. Instead, a pointer |
| 110 | * than free() you will need to roll-your-own. | 93 | * to storage is always returned. |
| 94 | * The 'cleanfn' function of the key structure is called to free the storage. | ||
| 95 | * If 'cleanfn' is NULL, then free() is used. This hook can be useful for | ||
| 96 | * getting rid of memory leaks. | ||
| 111 | */ | 97 | */ |
| 112 | #define _THREAD_PRIVATE(keyname, _initv, _errv) \ | 98 | #define _THREAD_PRIVATE(keyname, storage, error) \ |
| 113 | ({ \ | 99 | _libc_private_storage(&__THREAD_KEY_NAME(keyname), \ |
| 114 | struct _thread_private_key_struct * __k = \ | 100 | &(storage), sizeof (storage), error) |
| 115 | &__THREAD_KEY_NAME(keyname); \ | ||
| 116 | void* __p; \ | ||
| 117 | extern void free __P((void*)); \ | ||
| 118 | extern void* malloc __P((size_t)); \ | ||
| 119 | \ | ||
| 120 | if (!__isthreaded) { \ | ||
| 121 | /* non-threaded behaviour */ \ | ||
| 122 | __p = &(_initv); \ | ||
| 123 | goto _ok; \ | ||
| 124 | } \ | ||
| 125 | \ | ||
| 126 | /* create key for first thread */ \ | ||
| 127 | pthread_mutex_lock(&__k->lock); \ | ||
| 128 | if (__k->init == 0) { \ | ||
| 129 | if (pthread_key_create(&__k->key, free)) { \ | ||
| 130 | pthread_mutex_unlock(&__k->lock); \ | ||
| 131 | goto _err; \ | ||
| 132 | } \ | ||
| 133 | __k->init = 1; \ | ||
| 134 | } \ | ||
| 135 | pthread_mutex_unlock(&__k->lock); \ | ||
| 136 | \ | ||
| 137 | if ((__p = pthread_getspecific(__k->key)) == NULL) { \ | ||
| 138 | /* alloc space on 1st call in this thread */ \ | ||
| 139 | if ((__p = malloc(sizeof(_initv))) == NULL) \ | ||
| 140 | goto _err; \ | ||
| 141 | if (pthread_setspecific(__k->key, __p) != 0) { \ | ||
| 142 | free(__p); \ | ||
| 143 | goto _err; \ | ||
| 144 | } \ | ||
| 145 | /* initialise with _initv */ \ | ||
| 146 | memcpy(__p, &_initv, sizeof(_initv)); \ | ||
| 147 | } \ | ||
| 148 | goto _ok; \ | ||
| 149 | _err: \ | ||
| 150 | __p = (_errv); \ | ||
| 151 | _ok: \ | ||
| 152 | __p; \ | ||
| 153 | }) | ||
| 154 | 101 | ||
| 155 | /* | 102 | /* |
| 156 | * Macros for locking and unlocking FILEs. These test if the | 103 | * Macros for locking and unlocking FILEs. These test if the |
| 157 | * process is threaded to avoid locking when not required. | 104 | * process is threaded to avoid locking when not required. |
| 158 | */ | 105 | */ |
| 159 | #define FLOCKFILE(fp) if (__isthreaded) _FLOCKFILE(fp) | 106 | #ifdef _FLOCK_DEBUG |
| 160 | #define FUNLOCKFILE(fp) if (__isthreaded) funlockfile(fp) | 107 | #define FLOCKFILE(fp) _flockfile_debug(fp, __FILE__, __LINE__) |
| 161 | 108 | #else | |
| 162 | #else /* !_THREAD_SAFE */ | 109 | #define FLOCKFILE(fp) flockfile(fp) |
| 110 | #endif | ||
| 111 | #define FUNLOCKFILE(fp) funlockfile(fp) | ||
| 163 | 112 | ||
| 164 | /* | 113 | /* |
| 165 | * Do-nothing macros for single-threaded case. | 114 | * File descriptor locking definitions. |
| 166 | */ | 115 | */ |
| 167 | #define _FD_LOCK(f,o,p) (0) | 116 | #define FD_READ 0x1 |
| 168 | #define _FD_UNLOCK(f,o) /* nothing */ | 117 | #define FD_WRITE 0x2 |
| 169 | #define _THREAD_PRIVATE_KEY(_key) /* nothing */ | 118 | #define FD_RDWR (FD_READ | FD_WRITE) |
| 170 | #define _THREAD_PRIVATE(keyname, _initv, _errv) (&(_initv)) | 119 | |
| 171 | #define _THREAD_PRIVATE_MUTEX(_name) /* nothing */ | 120 | #ifdef _LOCK_DEBUG |
| 172 | #define _THREAD_PRIVATE_MUTEX_LOCK(_name) /* nothing */ | 121 | #define _FD_LOCK(_fd,_type,_ts) _thread_fd_lock_debug(_fd, _type, \ |
| 173 | #define _THREAD_PRIVATE_MUTEX_UNLOCK(_name) /* nothing */ | 122 | _ts, __FILE__, __LINE__) |
| 174 | #define FLOCKFILE(fp) /* nothing */ | 123 | #define _FD_UNLOCK(_fd,_type) _thread_fd_unlock_debug(_fd, _type, \ |
| 175 | #define FUNLOCKFILE(fp) /* nothing */ | 124 | __FILE__, __LINE__) |
| 176 | 125 | #else | |
| 177 | #endif /* !_THREAD_SAFE */ | 126 | #define _FD_LOCK(_fd,_type,_ts) _thread_fd_lock(_fd, _type, _ts) |
| 127 | #define _FD_UNLOCK(_fd,_type) _thread_fd_unlock(_fd, _type) | ||
| 128 | #endif | ||
| 129 | |||
| 130 | int _thread_fd_lock(int, int, struct timespec *); | ||
| 131 | int _thread_fd_lock_debug(int, int, struct timespec *, const char *, int); | ||
| 132 | void _thread_fd_unlock(int, int); | ||
| 133 | void _thread_fd_unlock_debug(int, int, const char *, int); | ||
| 178 | 134 | ||
| 179 | #endif _THREAD_PRIVATE_H_ | 135 | #endif _THREAD_PRIVATE_H_ |
