source: trunk/kernel/syscalls/sys_wait.c @ 459

Last change on this file since 459 was 457, checked in by alain, 3 years ago

This version modifies the exec syscall and fixes a large number of small bugs.
The version number has been updated (0.1)

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/////////////////////////////////
34int sys_wait( uint32_t * status )
35{
36        error_t     error;
37    vseg_t    * vseg;
38    xptr_t      iter_xp;
39    xptr_t      child_xp;
40    process_t * child_ptr;
41    cxy_t       child_cxy;
42    pid_t       child_pid;
43    uint32_t    child_state;
44    thread_t  * child_thread;
45    reg_t       save_sr;
46
47    thread_t  * this    = CURRENT_THREAD;
48    process_t * process = this->process;
49    pid_t       pid     = process->pid;
50
51#if DEBUG_SYS_WAIT
52uint64_t    cycle = hal_get_cycles();
53if( DEBUG_SYS_WAIT < cycle )
54printk("\n[DBG] %s : thread %x in process %x enter / cycle %d\n",
55__FUNCTION__, this, process->pid, (uint32_t)cycle );
56#endif
57
58    // check status in user space
59    error = vmm_get_vseg( process, (intptr_t)status , &vseg );
60
61        if( error )
62        {
63
64#if DEBUG_SYSCALLS_ERROR
65printk("\n[ERROR] in %s : status buffer %x unmapped for thread %x in process %x\n",
66__FUNCTION__ , (intptr_t)status, this->trdid , process->pid );
67vmm_display( process , false );
68#endif
69        this->errno = EINVAL;
70                return -1;
71        }
72
73    // get calling process owner cluster
74    cxy_t   owner_cxy = CXY_FROM_PID( pid );
75
76    // get calling thread trdid
77    trdid_t trdid = this->trdid;
78
79    // this function must be executed by the process main thread
80    if( (owner_cxy != local_cxy) || (LTID_FROM_TRDID(trdid) != 0) )
81    {
82
83#if DEBUG_SYSCALLS_ERROR
84printk("\n[ERROR] in %s : calling thread %x is not thread 0 in owner cluster %x\n",
85__FUNCTION__ , trdid , owner_cxy );
86#endif
87        this->errno = EINVAL;
88                return -1;
89        }
90
91    // get extended pointer on children list root and lock
92    xptr_t children_root_xp = XPTR( owner_cxy , &process->children_root );
93    xptr_t children_lock_xp = XPTR( owner_cxy , &process->children_lock );
94
95    // exit this blocking loop only when a child processes change state
96    while( 1 )
97    {
98        // enable IRQS
99        hal_enable_irq( &save_sr );
100 
101        // get lock protecting children list
102        remote_spinlock_lock( children_lock_xp );
103
104        // scan the list of child process
105        XLIST_FOREACH( children_root_xp , iter_xp )
106        {
107            // get child process owner cluster and local pointer
108            child_xp  = XLIST_ELEMENT( iter_xp , process_t , children_list );
109            child_ptr = GET_PTR( child_xp );
110            child_cxy = GET_CXY( child_xp );
111
112            // get PID, term_state, and main thread from child process
113            child_pid    = hal_remote_lw (XPTR( child_cxy , &child_ptr->pid ));
114            child_state  = hal_remote_lw ( XPTR(child_cxy , &child_ptr->term_state ) );
115            child_thread = hal_remote_lpt(XPTR( child_cxy , &child_ptr->th_tbl[0] ));
116
117#if (DEBUG_SYS_WAIT &1)
118cycle = hal_get_cycles();
119if( DEBUG_SYS_WAIT < cycle )
120printk("\n[DBG] %s : thread %x in process %x check child %x / state %x\n",
121__FUNCTION__, this, process->pid, child_pid, child_state );
122#endif
123            // test if this child process is terminated,
124            // but termination not yet reported to parent process
125            if( ((child_state & PROCESS_TERM_EXIT)  || 
126                 (child_state & PROCESS_TERM_KILL)  ||
127                 (child_state & PROCESS_TERM_STOP)) &&
128                 ((child_state & PROCESS_TERM_WAIT) == 0) )
129            {
130                // set the PROCESS_FLAG_WAIT in child process descriptor
131                hal_remote_atomic_or( XPTR( child_cxy , &child_ptr->term_state ),
132                                      PROCESS_TERM_WAIT );
133
134                // set the THREAD_FLAG_REQ_DELETE in main thread if kill or exit
135                if((child_state & PROCESS_TERM_EXIT) || (child_state & PROCESS_TERM_KILL))
136                hal_remote_atomic_or( XPTR( child_cxy , &child_thread->flags ) ,
137                                            THREAD_FLAG_REQ_DELETE );
138
139                // release lock protecting children list
140                remote_spinlock_unlock( children_lock_xp );
141
142#if DEBUG_SYS_WAIT
143cycle = hal_get_cycles();
144if( DEBUG_SYS_WAIT < cycle )
145{
146    if     ( child_state & PROCESS_TERM_EXIT )
147        printk("\n[DBG] %s : thread %x in process %x exit / child %x exit / cycle %d\n",
148        __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
149    if( child_state & PROCESS_TERM_KILL )
150        printk("\n[DBG] %s : thread %x in process %x exit / child %x killed / cycle %d\n",
151        __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
152    if( child_state & PROCESS_TERM_STOP )
153        printk("\n[DBG] %s : thread %x in process %x exit / child %x stopped / cycle %d\n",
154        __FUNCTION__, this, process->pid, child_pid, (uint32_t)cycle );
155}
156#endif
157                 // return child termination state  to parent process
158                 hal_copy_to_uspace( status , &child_state , sizeof(int) );
159                 return child_pid;
160            }
161        }  // end loop on children
162       
163        // block on WAIT condition
164        thread_block( XPTR( local_cxy , this ) , THREAD_BLOCKED_WAIT );
165
166        // release lock protecting children list
167        remote_spinlock_unlock( children_lock_xp );
168
169#if (DEBUG_SYS_WAIT & 1)
170cycle = hal_get_cycles();
171if( DEBUG_SYS_WAIT < cycle )
172printk("\n[DBG] %s : thread %x in process %x block & deschedule / cycle %d\n",
173__FUNCTION__, this, process->pid, (uint32_t)cycle );
174#endif
175
176        // deschedule
177        sched_yield( "parent process wait children processes termination" );
178
179#if (DEBUG_SYS_WAIT & 1)
180cycle = hal_get_cycles();
181if( DEBUG_SYS_WAIT < cycle )
182printk("\n[DBG] %s : thread %x in process %x unblock & resume / cycle %d\n",
183__FUNCTION__, this, process->pid, (uint32_t)cycle );
184#endif
185
186    }  // end while
187
188    // never executed
189        return -1; 
190
191}  // end sys_wait()
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