source: trunk/kernel/syscalls/sys_wait.c @ 506

Last change on this file since 506 was 506, checked in by viala@…, 3 years ago

[syscalls] add interface in implementation.

Add const where possible, fix protoypes to follow interface.

File size: 6.6 KB
Line 
1/*
2 * sys_wait.c - wait termination or blocking of a child process.
3 *
4 * Author    Alain Greiner (2016,2017,2018)
5 * 
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include <hal_kernel_types.h>
25#include <hal_uspace.h>
26#include <hal_irqmask.h>
27#include <core.h>
28#include <thread.h>
29#include <process.h>
30#include <vmm.h>
31#include <printk.h>
32
33#include <syscalls.h>
34
35/////////////////////////////////
36int sys_wait( uint32_t * status )
37{
38        error_t     error;
39    vseg_t    * vseg;
40    xptr_t      iter_xp;
41    xptr_t      child_xp;
42    process_t * child_ptr;
43    cxy_t       child_cxy;
44    pid_t       child_pid;
45    uint32_t    child_state;
46    thread_t  * child_thread;
47    reg_t       save_sr;
48
49    thread_t  * this    = CURRENT_THREAD;
50    process_t * process = this->process;
51    pid_t       pid     = process->pid;
52
53#if DEBUG_SYS_WAIT
54uint64_t    cycle = hal_get_cycles();
55if( DEBUG_SYS_WAIT < cycle )
56printk("\n[DBG] %s : thread %x in process %x enter / cycle %d\n",
57__FUNCTION__, this, process->pid, (uint32_t)cycle );
58#endif
59
60    // check status in user space
61    error = vmm_get_vseg( process, (intptr_t)status , &vseg );
62
63        if( error )
64        {
65
66#if DEBUG_SYSCALLS_ERROR
67printk("\n[ERROR] in %s : status buffer %x unmapped for thread %x in process %x\n",
68__FUNCTION__ , (intptr_t)status, this->trdid , process->pid );
69vmm_display( process , false );
70#endif
71        this->errno = EINVAL;
72                return -1;
73        }
74
75    // get calling process owner cluster
76    cxy_t   owner_cxy = CXY_FROM_PID( pid );
77
78    // get calling thread trdid
79    trdid_t trdid = this->trdid;
80
81    // this function must be executed by the process main thread
82    if( (owner_cxy != local_cxy) || (LTID_FROM_TRDID(trdid) != 0) )
83    {
84
85#if DEBUG_SYSCALLS_ERROR
86printk("\n[ERROR] in %s : calling thread %x is not thread 0 in owner cluster %x\n",
87__FUNCTION__ , trdid , owner_cxy );
88#endif
89        this->errno = EINVAL;
90                return -1;
91        }
92
93    // get extended pointer on children list root and lock
94    xptr_t children_root_xp = XPTR( owner_cxy , &process->children_root );
95    xptr_t children_lock_xp = XPTR( owner_cxy , &process->children_lock );
96
97    // exit this blocking loop only when a child processes change state
98    while( 1 )
99    {
100        // enable IRQS
101        hal_enable_irq( &save_sr );
102 
103        // get lock protecting children list
104        remote_spinlock_lock( children_lock_xp );
105
106        // scan the list of child process
107        XLIST_FOREACH( children_root_xp , iter_xp )
108        {
109            // get child process owner cluster and local pointer
110            child_xp  = XLIST_ELEMENT( iter_xp , process_t , children_list );
111            child_ptr = GET_PTR( child_xp );
112            child_cxy = GET_CXY( child_xp );
113
114            // get PID, term_state, and main thread from child process
115            child_pid    = hal_remote_lw (XPTR( child_cxy , &child_ptr->pid ));
116            child_state  = hal_remote_lw ( XPTR(child_cxy , &child_ptr->term_state ) );
117            child_thread = hal_remote_lpt(XPTR( child_cxy , &child_ptr->th_tbl[0] ));
118
119#if (DEBUG_SYS_WAIT &1)
120cycle = hal_get_cycles();
121if( DEBUG_SYS_WAIT < cycle )
122printk("\n[DBG] %s : thread %x in process %x check child %x / state %x\n",
123__FUNCTION__, this, process->pid, child_pid, child_state );
124#endif
125            // test if this child process is terminated,
126            // but termination not yet reported to parent process
127            if( ((child_state & PROCESS_TERM_EXIT)  || 
128                 (child_state & PROCESS_TERM_KILL)  ||
129                 (child_state & PROCESS_TERM_STOP)) &&
130                 ((child_state & PROCESS_TERM_WAIT) == 0) )
131            {
132                // set the PROCESS_FLAG_WAIT in child process descriptor
133                hal_remote_atomic_or( XPTR( child_cxy , &child_ptr->term_state ),
134                                      PROCESS_TERM_WAIT );
135
136                // set the THREAD_FLAG_REQ_DELETE in main thread if kill or exit
137                if((child_state & PROCESS_TERM_EXIT) || (child_state & PROCESS_TERM_KILL))
138                hal_remote_atomic_or( XPTR( child_cxy , &child_thread->flags ) ,
139                                            THREAD_FLAG_REQ_DELETE );
140
141                // release lock protecting children list
142                remote_spinlock_unlock( children_lock_xp );
143
144#if DEBUG_SYS_WAIT
145cycle = hal_get_cycles();
146if( DEBUG_SYS_WAIT < cycle )
147{
148    if     ( child_state & PROCESS_TERM_EXIT )
149        printk("\n[DBG] %s : thread %x in process %x exit / child %x exit / cycle %d\n",
150        __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
151    if( child_state & PROCESS_TERM_KILL )
152        printk("\n[DBG] %s : thread %x in process %x exit / child %x killed / cycle %d\n",
153        __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
154    if( child_state & PROCESS_TERM_STOP )
155        printk("\n[DBG] %s : thread %x in process %x exit / child %x stopped / cycle %d\n",
156        __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
157}
158#endif
159                 // return child termination state  to parent process
160                 hal_copy_to_uspace( status , &child_state , sizeof(int) );
161                 return child_pid;
162            }
163        }  // end loop on children
164       
165        // block on WAIT condition
166        thread_block( XPTR( local_cxy , this ) , THREAD_BLOCKED_WAIT );
167
168        // release lock protecting children list
169        remote_spinlock_unlock( children_lock_xp );
170
171#if (DEBUG_SYS_WAIT & 1)
172cycle = hal_get_cycles();
173if( DEBUG_SYS_WAIT < cycle )
174printk("\n[DBG] %s : thread %x in process %x block & deschedule / cycle %d\n",
175__FUNCTION__, this, process->pid, (uint32_t)cycle );
176#endif
177
178        // deschedule
179        sched_yield( "parent process wait children processes termination" );
180
181#if (DEBUG_SYS_WAIT & 1)
182cycle = hal_get_cycles();
183if( DEBUG_SYS_WAIT < cycle )
184printk("\n[DBG] %s : thread %x in process %x unblock & resume / cycle %d\n",
185__FUNCTION__, this, process->pid, (uint32_t)cycle );
186#endif
187
188    }  // end while
189
190    // never executed
191        return -1; 
192
193}  // end sys_wait()
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