1 | /* Linuxthreads - a simple clone()-based implementation of Posix */ |
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2 | /* threads for Linux. */ |
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3 | /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ |
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4 | /* */ |
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5 | /* This program is free software; you can redistribute it and/or */ |
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6 | /* modify it under the terms of the GNU Library General Public License */ |
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7 | /* as published by the Free Software Foundation; either version 2 */ |
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8 | /* of the License, or (at your option) any later version. */ |
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9 | /* */ |
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10 | /* This program is distributed in the hope that it will be useful, */ |
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11 | /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ |
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12 | /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ |
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13 | /* GNU Library General Public License for more details. */ |
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14 | |
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15 | /* Thread termination and joining */ |
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16 | |
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17 | #include <errno.h> |
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18 | #include <sched.h> |
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19 | #include <stdlib.h> |
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20 | #include <unistd.h> |
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21 | #include "pthread.h" |
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22 | #include "internals.h" |
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23 | #include "spinlock.h" |
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24 | #include "restart.h" |
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25 | |
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26 | void pthread_exit(void * retval) |
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27 | { |
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28 | __pthread_do_exit (retval, CURRENT_STACK_FRAME); |
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29 | } |
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30 | |
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31 | void __pthread_do_exit(void *retval, char *currentframe) |
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32 | { |
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33 | pthread_descr self = thread_self(); |
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34 | pthread_descr joining; |
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35 | struct pthread_request request; |
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36 | |
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37 | /* Reset the cancellation flag to avoid looping if the cleanup handlers |
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38 | contain cancellation points */ |
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39 | THREAD_SETMEM(self, p_canceled, 0); |
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40 | /* Call cleanup functions and destroy the thread-specific data */ |
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41 | __pthread_perform_cleanup(currentframe); |
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42 | __pthread_destroy_specifics(); |
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43 | /* Store return value */ |
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44 | __pthread_lock(THREAD_GETMEM(self, p_lock), self); |
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45 | THREAD_SETMEM(self, p_retval, retval); |
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46 | /* See whether we have to signal the death. */ |
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47 | if (THREAD_GETMEM(self, p_report_events)) |
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48 | { |
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49 | /* See whether TD_DEATH is in any of the mask. */ |
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50 | int idx = __td_eventword (TD_DEATH); |
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51 | uint32_t mask = __td_eventmask (TD_DEATH); |
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52 | |
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53 | if ((mask & (__pthread_threads_events.event_bits[idx] |
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54 | | THREAD_GETMEM_NC(self, |
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55 | p_eventbuf.eventmask.event_bits[idx]))) |
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56 | != 0) |
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57 | { |
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58 | /* Yep, we have to signal the death. */ |
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59 | THREAD_SETMEM(self, p_eventbuf.eventnum, TD_DEATH); |
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60 | THREAD_SETMEM(self, p_eventbuf.eventdata, self); |
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61 | __pthread_last_event = self; |
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62 | |
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63 | /* Now call the function to signal the event. */ |
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64 | __linuxthreads_death_event(); |
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65 | } |
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66 | } |
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67 | /* Say that we've terminated */ |
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68 | THREAD_SETMEM(self, p_terminated, 1); |
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69 | /* See if someone is joining on us */ |
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70 | joining = THREAD_GETMEM(self, p_joining); |
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71 | __pthread_unlock(THREAD_GETMEM(self, p_lock)); |
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72 | /* Restart joining thread if any */ |
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73 | if (joining != NULL) restart(joining); |
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74 | /* If this is the initial thread, block until all threads have terminated. |
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75 | If another thread calls exit, we'll be terminated from our signal |
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76 | handler. */ |
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77 | if (self == __pthread_main_thread && __pthread_manager_request >= 0) { |
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78 | request.req_thread = self; |
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79 | request.req_kind = REQ_MAIN_THREAD_EXIT; |
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80 | TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request, |
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81 | (char *)&request, sizeof(request))); |
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82 | suspend(self); |
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83 | /* Main thread flushes stdio streams and runs atexit functions. |
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84 | It also calls a handler within LinuxThreads which sends a process exit |
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85 | request to the thread manager. */ |
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86 | exit(0); |
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87 | } |
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88 | /* Threads other than the main one terminate without flushing stdio streams |
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89 | or running atexit functions. */ |
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90 | _exit(0); |
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91 | } |
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92 | |
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93 | /* Function called by pthread_cancel to remove the thread from |
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94 | waiting on a condition variable queue. */ |
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95 | |
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96 | static int join_extricate_func(void *obj, pthread_descr th) |
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97 | { |
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98 | volatile pthread_descr self = thread_self(); |
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99 | pthread_handle handle = obj; |
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100 | pthread_descr jo; |
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101 | int did_remove = 0; |
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102 | |
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103 | __pthread_lock(&handle->h_lock, self); |
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104 | jo = handle->h_descr; |
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105 | did_remove = jo->p_joining != NULL; |
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106 | jo->p_joining = NULL; |
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107 | __pthread_unlock(&handle->h_lock); |
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108 | |
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109 | return did_remove; |
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110 | } |
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111 | |
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112 | int pthread_join(pthread_t thread_id, void ** thread_return) |
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113 | { |
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114 | volatile pthread_descr self = thread_self(); |
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115 | struct pthread_request request; |
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116 | pthread_handle handle = thread_handle(thread_id); |
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117 | pthread_descr th; |
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118 | pthread_extricate_if extr; |
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119 | int already_canceled = 0; |
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120 | |
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121 | /* Set up extrication interface */ |
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122 | extr.pu_object = handle; |
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123 | extr.pu_extricate_func = join_extricate_func; |
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124 | |
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125 | __pthread_lock(&handle->h_lock, self); |
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126 | if (nonexisting_handle(handle, thread_id)) { |
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127 | __pthread_unlock(&handle->h_lock); |
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128 | return ESRCH; |
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129 | } |
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130 | th = handle->h_descr; |
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131 | if (th == self) { |
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132 | __pthread_unlock(&handle->h_lock); |
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133 | return EDEADLK; |
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134 | } |
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135 | /* If detached or already joined, error */ |
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136 | if (th->p_detached || th->p_joining != NULL) { |
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137 | __pthread_unlock(&handle->h_lock); |
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138 | return EINVAL; |
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139 | } |
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140 | /* If not terminated yet, suspend ourselves. */ |
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141 | if (! th->p_terminated) { |
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142 | /* Register extrication interface */ |
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143 | __pthread_set_own_extricate_if(self, &extr); |
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144 | if (!(THREAD_GETMEM(self, p_canceled) |
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145 | && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)) |
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146 | th->p_joining = self; |
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147 | else |
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148 | already_canceled = 1; |
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149 | __pthread_unlock(&handle->h_lock); |
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150 | |
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151 | if (already_canceled) { |
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152 | __pthread_set_own_extricate_if(self, 0); |
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153 | __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); |
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154 | } |
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155 | |
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156 | suspend(self); |
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157 | /* Deregister extrication interface */ |
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158 | __pthread_set_own_extricate_if(self, 0); |
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159 | |
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160 | /* This is a cancellation point */ |
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161 | if (THREAD_GETMEM(self, p_woken_by_cancel) |
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162 | && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) { |
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163 | THREAD_SETMEM(self, p_woken_by_cancel, 0); |
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164 | __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); |
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165 | } |
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166 | __pthread_lock(&handle->h_lock, self); |
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167 | } |
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168 | /* Get return value */ |
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169 | if (thread_return != NULL) *thread_return = th->p_retval; |
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170 | __pthread_unlock(&handle->h_lock); |
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171 | /* Send notification to thread manager */ |
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172 | if (__pthread_manager_request >= 0) { |
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173 | request.req_thread = self; |
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174 | request.req_kind = REQ_FREE; |
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175 | request.req_args.free.thread_id = thread_id; |
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176 | TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request, |
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177 | (char *) &request, sizeof(request))); |
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178 | } |
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179 | return 0; |
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180 | } |
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181 | |
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182 | int pthread_detach(pthread_t thread_id) |
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183 | { |
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184 | int terminated; |
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185 | struct pthread_request request; |
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186 | pthread_handle handle = thread_handle(thread_id); |
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187 | pthread_descr th; |
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188 | |
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189 | __pthread_lock(&handle->h_lock, NULL); |
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190 | if (nonexisting_handle(handle, thread_id)) { |
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191 | __pthread_unlock(&handle->h_lock); |
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192 | return ESRCH; |
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193 | } |
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194 | th = handle->h_descr; |
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195 | /* If already detached, error */ |
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196 | if (th->p_detached) { |
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197 | __pthread_unlock(&handle->h_lock); |
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198 | return EINVAL; |
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199 | } |
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200 | /* If already joining, don't do anything. */ |
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201 | if (th->p_joining != NULL) { |
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202 | __pthread_unlock(&handle->h_lock); |
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203 | return 0; |
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204 | } |
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205 | /* Mark as detached */ |
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206 | th->p_detached = 1; |
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207 | terminated = th->p_terminated; |
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208 | __pthread_unlock(&handle->h_lock); |
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209 | /* If already terminated, notify thread manager to reclaim resources */ |
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210 | if (terminated && __pthread_manager_request >= 0) { |
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211 | request.req_thread = thread_self(); |
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212 | request.req_kind = REQ_FREE; |
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213 | request.req_args.free.thread_id = thread_id; |
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214 | TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request, |
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215 | (char *) &request, sizeof(request))); |
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216 | } |
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217 | return 0; |
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218 | } |
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