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001 /* Copyright (C) 2004 David Decotigny 002 003 This program is free software; you can redistribute it and/or 004 modify it under the terms of the GNU General Public License 005 as published by the Free Software Foundation; either version 2 006 of the License, or (at your option) any later version. 007 008 This program is distributed in the hope that it will be useful, 009 but WITHOUT ANY WARRANTY; without even the implied warranty of 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 011 GNU General Public License for more details. 012 013 You should have received a copy of the GNU General Public License 014 along with this program; if not, write to the Free Software 015 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 016 USA. 017 */ 018 #ifndef _SOS_KSYNCH_H_ 019 #define _SOS_KSYNCH_H_ 020 021 022 /** 023 * @file synch.h 024 * 025 * Common kernel synchronisation primitives. 026 */ 027 028 029 #include <sos/errno.h> 030 #include <sos/kwaitq.h> 031 032 033 /* ==================================================================== 034 * Kernel semaphores, NON-recursive 035 */ 036 037 038 /** 039 * The structure of a (NON-RECURSIVE) kernel Semaphore 040 */ 041 struct sos_ksema 042 { 043 int value; 044 struct sos_kwaitq kwaitq; 045 }; 046 047 048 /* 049 * Initialize a kernel semaphore structure with the given name 050 * 051 * @param name Name of the semaphore (for debugging purpose only; safe 052 * [deep copied]) 053 * 054 * @param initial_value The value of the semaphore before any up/down 055 */ 056 sos_ret_t sos_ksema_init(struct sos_ksema *sema, const char *name, 057 int initial_value, 058 sos_kwaitq_ordering_t ordering); 059 060 061 /* 062 * De-initialize a kernel semaphore 063 * 064 * @return -SOS_EBUSY when semaphore could not be de-initialized 065 * because at least a thread is in the waitq. 066 */ 067 sos_ret_t sos_ksema_dispose(struct sos_ksema *sema); 068 069 070 /* 071 * Enters the semaphore 072 * 073 * @param timeout Maximum time to wait for the semaphore. Or NULL for 074 * "no limit". Updated on return to reflect the time remaining (0 when 075 * timeout has been triggered) 076 * 077 * @return -SOS_EINTR when timeout was triggered or when another waitq 078 * woke us up. 079 * 080 * @note This is a BLOCKING FUNCTION 081 */ 082 sos_ret_t sos_ksema_down(struct sos_ksema *sema, 083 struct sos_time *timeout); 084 085 086 /* 087 * Try to enter the semaphore without blocking. 088 * 089 * @return -SOS_EBUSY when locking the semaphore would block 090 */ 091 sos_ret_t sos_ksema_trydown(struct sos_ksema *sema); 092 093 094 /** 095 * Increments the semaphore's value, eventually waking up a thread 096 */ 097 sos_ret_t sos_ksema_up(struct sos_ksema *sema); 098 099 100 101 /* ==================================================================== 102 * Kernel mutex (ie binary semaphore with strong ownership), 103 * NON-recursive ! 104 */ 105 106 107 /** 108 * The structure of a (NON-RECURSIVE) kernel Mutex 109 */ 110 struct sos_kmutex 111 { 112 struct sos_thread *owner; 113 struct sos_kwaitq kwaitq; 114 }; 115 116 117 /* 118 * Initialize a kernel mutex structure with the given name 119 * 120 * @param name Name of the mutex (for debugging purpose only; safe 121 * [deep copied]) 122 * 123 * @param initial_value The value of the mutex before any up/down 124 */ 125 sos_ret_t sos_kmutex_init(struct sos_kmutex *mutex, const char *name, 126 sos_kwaitq_ordering_t ordering); 127 128 129 /* 130 * De-initialize a kernel mutex 131 * 132 * @return -SOS_EBUSY when mutex could not be de-initialized 133 * because at least a thread is in the waitq. 134 */ 135 sos_ret_t sos_kmutex_dispose(struct sos_kmutex *mutex); 136 137 138 /* 139 * Lock the mutex. If the same thread multiply locks the same mutex, 140 * it won't hurt (no deadlock, return value = -SOS_EBUSY). 141 * 142 * @param timeout Maximum time to wait for the mutex. Or NULL for "no 143 * limit". Updated on return to reflect the time remaining (0 when 144 * timeout has been triggered) 145 * 146 * @return -SOS_EINTR when timeout was triggered or when another waitq 147 * woke us up, -SOS_EBUSY when the thread already owns the mutex. 148 * 149 * @note This is a BLOCKING FUNCTION 150 */ 151 sos_ret_t sos_kmutex_lock(struct sos_kmutex *mutex, 152 struct sos_time *timeout); 153 154 155 /* 156 * Try to lock the mutex without blocking. 157 * 158 * @return -SOS_EBUSY when locking the mutex would block 159 */ 160 sos_ret_t sos_kmutex_trylock(struct sos_kmutex *mutex); 161 162 163 /** 164 * Unlock the mutex, eventually waking up a thread 165 * 166 * @return -SOS_EPERM when the calling thread is NOT the owner of the 167 * mutex 168 */ 169 sos_ret_t sos_kmutex_unlock(struct sos_kmutex *mutex); 170 171 172 #endif /* _SOS_KSYNCH_H_ */
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