source: trunk/kernel/syscalls/sys_write.c @ 579

Last change on this file since 579 was 566, checked in by alain, 6 years ago

Complete restructuration of kernel locks.
File size: 7.9 KB
Line 
1/*
2 * sys_write.c - Kernel function implementing the "write" 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_irqmask.h>
28#include <hal_special.h>
29#include <errno.h>
30#include <vfs.h>
31#include <vmm.h>
32#include <thread.h>
33#include <printk.h>
34#include <process.h>
35
36
37extern uint32_t enter_sys_write;
38extern uint32_t enter_devfs_write;
39extern uint32_t enter_txt_write;
40extern uint32_t enter_chdev_cmd_write;
41extern uint32_t enter_chdev_server_write;
42extern uint32_t enter_tty_cmd_write;
43extern uint32_t enter_tty_isr_write;
44extern uint32_t exit_tty_isr_write;
45extern uint32_t exit_tty_cmd_write;
46extern uint32_t exit_chdev_server_write;
47extern uint32_t exit_chdev_cmd_write;
48extern uint32_t exit_txt_write;
49extern uint32_t exit_devfs_write;
50extern uint32_t exit_sys_write;
51
52//////////////////////////////////
53int sys_write( uint32_t   file_id,
54               void     * vaddr,
55               uint32_t   count )
56{
57    error_t      error;
58    vseg_t     * vseg;            // required for user space checking
59        xptr_t       file_xp;         // remote file extended pointer
60    uint32_t     nbytes;          // number of bytes actually written
61    reg_t        save_sr;         // required to enable IRQs during syscall
62
63        thread_t   * this = CURRENT_THREAD;
64        process_t  * process = this->process;
65
66#if (DEBUG_SYS_WRITE || CONFIG_INSTRUMENTATION_SYSCALLS)
67uint64_t     tm_start = hal_get_cycles();
68#endif
69
70#if DEBUG_SYS_WRITE
71tm_start = hal_get_cycles();
72if( DEBUG_SYS_WRITE < tm_start )
73printk("\n[DBG] %s : thread %x in process %x enter / vaddr %x / count %d / cycle %d\n",
74__FUNCTION__, this->trdid, process->pid, vaddr, count, (uint32_t)tm_start );
75#endif
76 
77#if (DEBUG_SYS_WRITE & 1)
78enter_sys_write = (uint32_t)tm_start;
79#endif
80
81    // check file_id argument
82        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
83        {
84
85#if DEBUG_SYSCALLS_ERROR
86printk("\n[ERROR] in %s : illegal file descriptor index\n", __FUNCTION__ );
87#endif
88        this->errno = EBADFD;
89                return -1;
90        }
91
92    // check user buffer in user space
93    error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
94
95    if ( error )
96    {
97
98#if DEBUG_SYSCALLS_ERROR
99printk("\n[ERROR] in %s : user buffer unmapped %x / thread %x / process %x\n",
100__FUNCTION__ , (intptr_t)vaddr, this->trdid, process->pid );
101vmm_display( process , false );
102#endif
103                this->errno = EINVAL;
104                return -1;
105    }
106
107    // get extended pointer on remote file descriptor
108    file_xp = process_fd_get_xptr( process , file_id );
109
110    if( file_xp == XPTR_NULL )
111    {
112
113#if DEBUG_SYSCALLS_ERROR
114printk("\n[ERROR] in %s : undefined file descriptor index = %d in process %x\n",
115__FUNCTION__ , file_id , process->pid );
116#endif
117                this->errno = EBADFD;
118                return -1;
119    }
120
121    // get file descriptor cluster and local pointer
122    vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
123    cxy_t        file_cxy = GET_CXY( file_xp );
124
125 
126    // get file type
127    vfs_inode_type_t type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
128
129    // enable IRQs
130    hal_enable_irq( &save_sr );
131
132   // action depend on file type
133    if( type == INODE_TYPE_FILE )  // check file writable & write to mapper
134    {
135        // check file writable
136        uint32_t attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
137        if( (attr & FD_ATTR_WRITE_ENABLE) == 0 )
138            {
139
140#if DEBUG_SYSCALLS_ERROR
141printk("\n[ERROR] in %s : file %d not writable in process %x\n",
142__FUNCTION__ , file_id , process->pid );
143#endif
144                    this->errno = EBADFD;
145                    return -1;
146            }
147
148        // move count bytes to mapper
149        nbytes = vfs_user_move( false,               // from buffer to mapper
150                                file_xp,
151                                vaddr, 
152                                count );
153    }
154    else if( type == INODE_TYPE_DEV )  // check ownership & write to device
155    {
156        // check user buffer size for TXT_TX
157        if( (type == INODE_TYPE_DEV) && (count >= CONFIG_TXT_KBUF_SIZE) )
158        {
159
160#if DEBUG_SYSCALLS_ERROR
161printk("\n[ERROR] in %s : user buffer size %x too large / thread %x / process %x\n",
162__FUNCTION__ , count, this->trdid, process->pid );
163#endif
164                    this->errno = EINVAL;
165                    return -1;
166        }
167
168        // move count bytes to device
169        nbytes = devfs_user_move( false,             // from buffer to device
170                                 file_xp,
171                                 vaddr,
172                                 count );
173    }
174    else  // not FILE and not DEV
175    {
176        nbytes = 0;
177        assert( false , "file type %d non supported\n", type );
178    }
179
180    if( nbytes != count )
181    {
182
183#if DEBUG_SYSCALLS_ERROR
184printk("\n[ERROR] in %s cannot write data to file %d in process %x\n",
185__FUNCTION__ , file_id , process->pid );
186#endif
187        this->errno = error;
188        return -1;
189    }
190
191    // restore IRQs
192    hal_restore_irq( save_sr );
193
194    hal_fence();
195
196#if (DEBUG_SYS_WRITE || CONFIG_INSTRUMENTATION_SYSCALLS)
197uint64_t     tm_end = hal_get_cycles();
198#endif
199
200#if DEBUG_SYS_WRITE
201if( DEBUG_SYS_WRITE < tm_end )
202printk("\n[DBG] %s : thread %x in process %x exit / cycle %d\n",
203__FUNCTION__, this->trdid, process->pid, (uint32_t)tm_end );
204#endif
205 
206#if CONFIG_INSTRUMENTATION_SYSCALLS
207hal_atomic_add( &syscalls_cumul_cost[SYS_WRITE] , tm_end - tm_start );
208hal_atomic_add( &syscalls_occurences[SYS_WRITE] , 1 );
209#endif
210
211#if (DEBUG_SYS_WRITE & 1)
212exit_sys_write = (uint32_t)tm_end;
213
214printk("\n***** timing to write a string *****\n"
215" - enter_sys_write          = %d / delta %d\n"
216" - enter_devfs_write        = %d / delta %d\n"
217" - enter_txt_write          = %d / delta %d\n"
218" - enter_chdev_cmd_write    = %d / delta %d\n"
219" - enter_chdev_server_write = %d / delta %d\n"
220" - enter_tty_cmd_write      = %d / delta %d\n"
221" - enter_tty_isr_write      = %d / delta %d\n"
222" - exit_tty_isr_write       = %d / delta %d\n"
223" - exit_tty_cmd_write       = %d / delta %d\n"
224" - exit_chdev_server_write  = %d / delta %d\n"
225" - exit_chdev_cmd_write     = %d / delta %d\n"
226" - exit_txt_write           = %d / delta %d\n"
227" - exit_devfs_write         = %d / delta %d\n"
228" - exit_sys_write           = %d / delta %d\n",
229enter_sys_write          , 0 ,
230enter_devfs_write        , enter_devfs_write        - enter_sys_write          ,
231enter_txt_write          , enter_txt_write          - enter_devfs_write        ,
232enter_chdev_cmd_write    , enter_chdev_cmd_write    - enter_txt_write          ,
233enter_chdev_server_write , enter_chdev_server_write - enter_chdev_cmd_write    ,
234enter_tty_cmd_write      , enter_tty_cmd_write      - enter_chdev_server_write ,
235enter_tty_isr_write      , enter_tty_isr_write      - enter_tty_cmd_write      ,
236exit_tty_isr_write       , exit_tty_isr_write       - enter_tty_isr_write      ,
237exit_tty_cmd_write       , exit_tty_cmd_write       - exit_tty_isr_write       ,
238exit_chdev_server_write  , exit_chdev_server_write  - exit_tty_cmd_write       ,
239exit_chdev_cmd_write     , exit_chdev_cmd_write     - exit_chdev_server_write  ,
240exit_txt_write           , exit_txt_write           - exit_chdev_cmd_write     ,
241exit_devfs_write         , exit_devfs_write         - exit_txt_write           ,
242exit_sys_write           , exit_sys_write           - exit_devfs_write         );
243#endif
244 
245        return nbytes;
246
247}  // end sys_write()
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