source: trunk/kernel/syscalls/sys_is_fg.c @ 469

Last change on this file since 469 was 469, checked in by alain, 3 years ago

1) Introduce the libsemaphore library.
2) Introduce a small libmath library, required by the "fft" application..
3) Introduce the multithreaded "fft" application.
4) Fix a bad synchronisation bug in the Copy-On-Write mechanism.

File size: 2.9 KB
Line 
1/*
2 * sys_fg.c - Kernel function implementing the "is_fg" system call.
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 <kernel_config.h>
25#include <hal_kernel_types.h>
26#include <hal_uspace.h>
27#include <hal_special.h>
28#include <errno.h>
29#include <thread.h>
30#include <printk.h>
31#include <process.h>
32#include <vseg.h>
33#include <shared_syscalls.h>
34#include <cluster.h>
35
36//////////////////////////////
37int sys_is_fg( pid_t      pid,
38               uint32_t * is_fg )
39{
40    xptr_t      process_xp;       // extended pointer on process descriptor in owner cluster
41    uint32_t    is_txt_owner;     // kernel buffer for is_fg
42    vseg_t    * vseg;             // for buffer mapping check
43    error_t     error;
44
45    thread_t  * this    = CURRENT_THREAD;
46    process_t * process = this->process;
47
48#if DEBUG_SYS_IS_FG
49uint64_t    tm_start;
50uint64_t    tm_end;
51tm_start = hal_get_cycles();
52if( DEBUG_SYS_FG < tm_start )
53printk("\n[DBG] %s : thread %x in process %x enter for pid %x / cycle %d\n",
54__FUNCTION__ , this->trdid , process->pid, pid, (uint32_t)tm_start );
55#endif
56
57    // check buffer in user vspace
58        error = vmm_get_vseg( process , (intptr_t)is_fg , &vseg );
59    if( error )
60    {
61
62#if DEBUG_SYSCALLS_ERROR
63printk("\n[ERROR] in %s : unmapped owner buffer %x / thread %x in process %x\n",
64__FUNCTION__ , (intptr_t)is_fg, this->trdid, process->pid );
65vmm_display( process , false );
66#endif
67         this->errno = EINVAL;
68         return -1;
69    }
70
71    // check target process existence
72    process_xp = cluster_get_owner_process_from_pid( pid );
73
74    if( process_xp == XPTR_NULL )
75    {
76
77#if DEBUG_SYSCALLS_ERROR
78printk("\n[ERROR] in %s : process %x not found\n", __FUNCTION__ , pid );
79#endif
80        this->errno = EINVAL;
81        return -1;
82    }
83   
84    // call relevant kernel function
85    is_txt_owner = process_txt_is_owner( process_xp );
86
87    // copy to user space
88    hal_copy_to_uspace( is_fg , &is_txt_owner , sizeof(uint32_t) );
89
90    hal_fence();
91
92#if DEBUG_SYS_IS_FG
93tm_end = hal_get_cycles();
94if( DEBUG_SYS_FG < tm_end )
95printk("\n[DBG] %s : thread %x in process %x exit / is_txt_owner %d / cycle %d\n",
96__FUNCTION__, this->trdid, process->pid, is_txt_owner, (uint32_t)tm_end );
97#endif
98
99        return 0;
100
101}  // end sys_is_fg()
102
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