| 1 | /*
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| 2 | * sys_wait.c - wait termination or blocking of a child process.
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| 3 | *
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| 4 | * Author Alain Greiner (2016,2017,2018)
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| 5 | *
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| 6 | * Copyright (c) UPMC Sorbonne Universites
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| 7 | *
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| 8 | * This file is part of ALMOS-MKH.
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| 9 | *
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| 10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it
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| 11 | * under the terms of the GNU General Public License as published by
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| 12 | * the Free Software Foundation; version 2.0 of the License.
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| 13 | *
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| 14 | * ALMOS-MKH is distributed in the hope that it will be useful, but
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 17 | * General Public License for more details.
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| 18 | *
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| 19 | * You should have received a copy of the GNU General Public License
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| 20 | * along with ALMOS-MKH; if not, write to the Free Software Foundation,
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| 21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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| 22 | */
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| 23 |
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| 24 | #include <hal_kernel_types.h>
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| 25 | #include <hal_uspace.h>
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| 26 | #include <hal_irqmask.h>
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| 27 | #include <remote_queuelock.h>
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| 28 | #include <core.h>
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| 29 | #include <thread.h>
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| 30 | #include <process.h>
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| 31 | #include <vmm.h>
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| 32 | #include <printk.h>
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| 33 |
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| 34 | #include <syscalls.h>
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| 35 |
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| 36 | /////////////////////////////////
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| 37 | int sys_wait( uint32_t * status )
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| 38 | {
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| 39 | error_t error;
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| 40 | vseg_t * vseg;
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| 41 | xptr_t iter_xp;
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| 42 | xptr_t child_xp;
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| 43 | process_t * child_ptr;
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| 44 | cxy_t child_cxy;
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| 45 | pid_t child_pid;
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| 46 | uint32_t child_state;
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| 47 | thread_t * child_thread;
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| 48 | reg_t save_sr;
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| 49 |
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| 50 | thread_t * this = CURRENT_THREAD;
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| 51 | process_t * process = this->process;
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| 52 | pid_t pid = process->pid;
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| 53 |
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| 54 | #if DEBUG_SYS_WAIT
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| 55 | uint64_t cycle = hal_get_cycles();
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| 56 | if( DEBUG_SYS_WAIT < cycle )
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| 57 | printk("\n[DBG] %s : thread %x in process %x enter / cycle %d\n",
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| 58 | __FUNCTION__, this, process->pid, (uint32_t)cycle );
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| 59 | #endif
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| 60 |
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| 61 | // check status in user space
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| 62 | error = vmm_get_vseg( process, (intptr_t)status , &vseg );
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| 63 |
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| 64 | if( error )
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| 65 | {
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| 66 |
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| 67 | #if DEBUG_SYSCALLS_ERROR
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| 68 | printk("\n[ERROR] in %s : status buffer %x unmapped for thread %x in process %x\n",
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| 69 | __FUNCTION__ , (intptr_t)status, this->trdid , process->pid );
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| 70 | vmm_display( process , false );
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| 71 | #endif
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| 72 | this->errno = EINVAL;
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| 73 | return -1;
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| 74 | }
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| 75 |
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| 76 | // get calling process owner cluster
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| 77 | cxy_t owner_cxy = CXY_FROM_PID( pid );
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| 78 |
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| 79 | // get calling thread trdid
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| 80 | trdid_t trdid = this->trdid;
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| 81 |
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| 82 | // this function must be executed by the process main thread
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| 83 | if( (owner_cxy != local_cxy) || (LTID_FROM_TRDID(trdid) != 0) )
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| 84 | {
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| 85 |
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| 86 | #if DEBUG_SYSCALLS_ERROR
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| 87 | printk("\n[ERROR] in %s : calling thread %x is not thread 0 in owner cluster %x\n",
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| 88 | __FUNCTION__ , trdid , owner_cxy );
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| 89 | #endif
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| 90 | this->errno = EINVAL;
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| 91 | return -1;
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| 92 | }
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| 93 |
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| 94 | // get extended pointer on children list root and lock
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| 95 | xptr_t children_root_xp = XPTR( owner_cxy , &process->children_root );
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| 96 | xptr_t children_lock_xp = XPTR( owner_cxy , &process->children_lock );
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| 97 |
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| 98 | // exit this loop only when a child processes change state
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| 99 | while( 1 )
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| 100 | {
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| 101 | // enable IRQS
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| 102 | hal_enable_irq( &save_sr );
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| 103 |
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| 104 | // get lock protecting children list
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| 105 | remote_queuelock_acquire( children_lock_xp );
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| 106 |
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| 107 | // scan the list of child process
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| 108 | XLIST_FOREACH( children_root_xp , iter_xp )
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| 109 | {
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| 110 | // get child process owner cluster and local pointer
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| 111 | child_xp = XLIST_ELEMENT( iter_xp , process_t , children_list );
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| 112 | child_ptr = GET_PTR( child_xp );
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| 113 | child_cxy = GET_CXY( child_xp );
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| 114 |
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| 115 | // get PID, term_state, and main thread from child process
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| 116 | child_pid = hal_remote_l32 (XPTR( child_cxy , &child_ptr->pid ));
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| 117 | child_state = hal_remote_l32 ( XPTR(child_cxy , &child_ptr->term_state ) );
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| 118 | child_thread = hal_remote_lpt(XPTR( child_cxy , &child_ptr->th_tbl[0] ));
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| 119 |
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| 120 | #if (DEBUG_SYS_WAIT & 1)
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| 121 | cycle = hal_get_cycles();
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| 122 | if( DEBUG_SYS_WAIT < cycle )
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| 123 | printk("\n[DBG] %s : thread %x in process %x check child %x / state %x\n",
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| 124 | __FUNCTION__, this, process->pid, child_pid, child_state );
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| 125 | #endif
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| 126 | // test if this child process is terminated,
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| 127 | // but termination not yet reported to parent process
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| 128 | if( ((child_state & PROCESS_TERM_EXIT) ||
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| 129 | (child_state & PROCESS_TERM_KILL) ||
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| 130 | (child_state & PROCESS_TERM_STOP)) &&
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| 131 | ((child_state & PROCESS_TERM_WAIT) == 0) )
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| 132 | {
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| 133 | // set the PROCESS_TERM_WAIT in child process descriptor
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| 134 | hal_remote_atomic_or( XPTR( child_cxy , &child_ptr->term_state ),
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| 135 | PROCESS_TERM_WAIT );
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| 136 |
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| 137 | // set the THREAD_FLAG_REQ_DELETE in main thread if kill or exit
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| 138 | if((child_state & PROCESS_TERM_EXIT) || (child_state & PROCESS_TERM_KILL))
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| 139 | hal_remote_atomic_or( XPTR( child_cxy , &child_thread->flags ) ,
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| 140 | THREAD_FLAG_REQ_DELETE );
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| 141 |
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| 142 | // release lock protecting children list
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| 143 | remote_queuelock_release( children_lock_xp );
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| 144 |
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| 145 | #if DEBUG_SYS_WAIT
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| 146 | cycle = hal_get_cycles();
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| 147 | if( DEBUG_SYS_WAIT < cycle )
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| 148 | {
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| 149 | if ( child_state & PROCESS_TERM_EXIT )
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| 150 | printk("\n[DBG] %s : thread %x in process %x exit / child %x exit / cycle %d\n",
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| 151 | __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
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| 152 | if( child_state & PROCESS_TERM_KILL )
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| 153 | printk("\n[DBG] %s : thread %x in process %x exit / child %x killed / cycle %d\n",
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| 154 | __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
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| 155 | if( child_state & PROCESS_TERM_STOP )
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| 156 | printk("\n[DBG] %s : thread %x in process %x exit / child %x stopped / cycle %d\n",
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| 157 | __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
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| 158 | }
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| 159 | #endif
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| 160 | // return child termination state to parent process
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| 161 | hal_copy_to_uspace( status , &child_state , sizeof(int) );
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| 162 | return child_pid;
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| 163 | }
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| 164 | } // end loop on children
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| 165 |
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| 166 | // we execute this code when no child terminated:
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| 167 | // - release the lock protecting children list,
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| 168 | // - block on the WAIT condition
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| 169 | // - deschedule to keep waiting in the while loop
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| 170 |
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| 171 | // release lock protecting children list
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| 172 | remote_queuelock_release( children_lock_xp );
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| 173 |
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| 174 | // block on WAIT condition
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| 175 | thread_block( XPTR( local_cxy , this ) , THREAD_BLOCKED_WAIT );
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| 176 |
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| 177 | #if (DEBUG_SYS_WAIT & 1)
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| 178 | cycle = hal_get_cycles();
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| 179 | if( DEBUG_SYS_WAIT < cycle )
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| 180 | printk("\n[DBG] %s : thread %x in process %x block & deschedule / cycle %d\n",
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| 181 | __FUNCTION__, this, process->pid, (uint32_t)cycle );
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| 182 | #endif
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| 183 |
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| 184 | // deschedule
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| 185 | sched_yield( "parent process wait children processes termination" );
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| 186 |
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| 187 | #if (DEBUG_SYS_WAIT & 1)
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| 188 | cycle = hal_get_cycles();
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| 189 | if( DEBUG_SYS_WAIT < cycle )
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| 190 | printk("\n[DBG] %s : thread %x in process %x unblock & resume / cycle %d\n",
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| 191 | __FUNCTION__, this, process->pid, (uint32_t)cycle );
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| 192 | #endif
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| 193 |
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| 194 | } // end while
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| 195 |
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| 196 | // never executed
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| 197 | return -1;
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| 198 |
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| 199 | } // end sys_wait()
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