source: trunk/kernel/syscalls/sys_write.c @ 433

Last change on this file since 433 was 433, checked in by alain, 4 years ago

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1/*
2 * sys_write.c - write bytes to a file
3 *
4 * Author        Alain Greiner (2016,2017)
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_types.h>
26#include <hal_uspace.h>
27#include <hal_irqmask.h>
28#include <hal_special.h>
29#include <errno.h>
30#include <vfs.h>
31#include <thread.h>
32#include <printk.h>
33#include <process.h>
34
35/* TODO: concurrent user page(s) unmap need to be handled [AG] */
36
37//////////////////////////////////
38int sys_write( uint32_t   file_id,
39               void     * vaddr,
40               uint32_t   count )
41{
42    error_t      error;
43    paddr_t      paddr;           // unused, but required for user space checking
44        xptr_t       file_xp;         // remote file extended pointer
45    uint32_t     nbytes;          // number of bytes actually written
46    reg_t        save_sr;         // required to enable IRQs during syscall
47
48        thread_t   * this = CURRENT_THREAD;
49        process_t  * process = this->process;
50
51#if CONFIG_DEBUG_SYS_WRITE
52uint32_t     tm_start;
53uint32_t     tm_end;
54tm_start = hal_get_cycles();
55if( CONFIG_DEBUG_SYS_WRITE < tm_start )
56printk("\n[DBG] %s : thread %x / process %x / vaddr %x / count %d / cycle %d\n",
57__FUNCTION__, this, process->pid, vaddr, count, (uint32_t)tm_start );
58#endif
59 
60    // check file_id argument
61        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
62        {
63
64#if CONFIG_DEBUG_SYSCALLS_ERROR
65printk("\n[ERROR] in %s : illegal file descriptor index\n", __FUNCTION__ );
66#endif
67        this->errno = EBADFD;
68                return -1;
69        }
70
71    // check user buffer in user space
72    error = vmm_v2p_translate( false , vaddr , &paddr );
73
74    if ( error )
75    {
76
77#if CONFIG_DEBUG_SYSCALLS_ERROR
78printk("\n[ERROR] in %s : user buffer unmapped = %x\n", __FUNCTION__ , (intptr_t)vaddr );
79#endif
80                this->errno = EINVAL;
81                return -1;
82    }
83
84    // enable IRQs
85    hal_enable_irq( &save_sr );
86
87    // get extended pointer on remote file descriptor
88    file_xp = process_fd_get_xptr( process , file_id );
89
90    if( file_xp == XPTR_NULL )
91    {
92
93#if CONFIG_DEBUG_SYSCALLS_ERROR
94printk("\n[ERROR] in %s : undefined file descriptor index = %d in process %x\n",
95__FUNCTION__ , file_id , process->pid );
96#endif
97                this->errno = EBADFD;
98                return -1;
99    }
100
101    // get file descriptor cluster and local pointer
102    vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
103    cxy_t        file_cxy = GET_CXY( file_xp );
104
105 
106    // get file type
107    vfs_inode_type_t type = hal_remote_lw( XPTR( file_cxy , &file_ptr->type ) );
108
109    // action depend on file type
110    if( type == INODE_TYPE_FILE )  // check file writable & write to mapper
111    {
112        // check file writable
113        uint32_t attr = hal_remote_lw( XPTR( file_cxy , &file_ptr->attr ) );
114        if( (attr & FD_ATTR_WRITE_ENABLE) == 0 )
115            {
116
117#if CONFIG_DEBUG_SYSCALLS_ERROR
118printk("\n[ERROR] in %s : file %d not writable in process %x\n",
119__FUNCTION__ , file_id , process->pid );
120#endif
121                    this->errno = EBADFD;
122                    return -1;
123            }
124
125        // move count bytes to mapper
126        nbytes = vfs_user_move( false,               // from buffer to mapper
127                                file_xp,
128                                vaddr, 
129                                count );
130    }
131    else if( type == INODE_TYPE_DEV )  // check ownership & write to device
132    {
133        // move count bytes to device
134        nbytes = devfs_user_move( false,             // from buffer to device
135                                 file_xp,
136                                 vaddr,
137                                 count );
138    }
139    else
140    {
141        nbytes = 0;
142        assert( false , __FUNCTION__ , "file type %d non supported\n", type );
143    }
144
145    if( nbytes != count )
146    {
147
148#if CONFIG_DEBUG_SYSCALLS_ERROR
149printk("\n[ERROR] in %s cannot write data to file %d in process %x\n",
150__FUNCTION__ , file_id , process->pid );
151#endif
152        this->errno = error;
153        return -1;
154    }
155
156    // restore IRQs
157    hal_restore_irq( save_sr );
158
159    hal_fence();
160
161#if CONFIG_DEBUG_SYS_WRITE
162tm_end = hal_get_cycles();
163if( CONFIG_DEBUG_SYS_WRITE < tm_end )
164printk("\n[DBG] %s : thread %x in process %x / cycle %d\n"
165"nbytes = %d / first byte = %c / file_id = %d / cost = %d\n",
166__FUNCTION__, this, process->pid, (uint32_t)tm_start,
167nbytes, *((char *)(intptr_t)paddr) , file_id , (uint32_t)(tm_end - tm_start) );
168#endif
169 
170        return nbytes;
171
172}  // end sys_write()
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