source: trunk/kernel/syscalls/sys_write.c @ 584

Last change on this file since 584 was 584, checked in by alain, 3 years ago

Introduce sys_place_fork() function.

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,%x] enter / vaddr %x / count %d / cycle %d\n",
74__FUNCTION__, process->pid, this->trdid, 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 : thread[%x,%x] illegal file descriptor index %d\n",
87__FUNCTION__, process->pid, this->trdid, file_id );
88#endif
89        this->errno = EBADFD;
90                return -1;
91        }
92
93    // check user buffer in user space
94    error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
95
96    if ( error )
97    {
98
99#if DEBUG_SYSCALLS_ERROR
100printk("\n[ERROR] in %s : thread[%x,%x] user buffer unmapped %x\n",
101__FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr );
102vmm_display( process , false );
103#endif
104                this->errno = EINVAL;
105                return -1;
106    }
107
108    // get extended pointer on remote file descriptor
109    file_xp = process_fd_get_xptr( process , file_id );
110
111    if( file_xp == XPTR_NULL )
112    {
113
114#if DEBUG_SYSCALLS_ERROR
115printk("\n[ERROR] in %s : thread[%x,%x] undefined file descriptor index = %d\n",
116__FUNCTION__, process->pid, this->trdid, file_id );
117#endif
118                this->errno = EBADFD;
119                return -1;
120    }
121
122    // get file descriptor cluster and local pointer
123    vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
124    cxy_t        file_cxy = GET_CXY( file_xp );
125
126 
127    // get file type
128    vfs_inode_type_t type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
129
130    // enable IRQs
131    hal_enable_irq( &save_sr );
132
133   // action depend on file type
134    if( type == INODE_TYPE_FILE )  // check file writable & write to mapper
135    {
136        // check file writable
137        uint32_t attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
138        if( (attr & FD_ATTR_WRITE_ENABLE) == 0 )
139            {
140
141#if DEBUG_SYSCALLS_ERROR
142printk("\n[ERROR] in %s : thread[%x,%x] file %d not writable\n",
143__FUNCTION__ , process->pid, this->trdid, file_id );
144#endif
145                    this->errno = EBADFD;
146                    return -1;
147            }
148
149        // move count bytes to mapper
150        nbytes = vfs_user_move( false,               // from buffer to mapper
151                                file_xp,
152                                vaddr, 
153                                count );
154    }
155    else if( type == INODE_TYPE_DEV )  // check ownership & write to device
156    {
157        // check user buffer size for TXT_TX
158        if( (type == INODE_TYPE_DEV) && (count >= CONFIG_TXT_KBUF_SIZE) )
159        {
160
161#if DEBUG_SYSCALLS_ERROR
162printk("\n[ERROR] in %s : thread[%x,%x] user buffer size %x too large\n",
163__FUNCTION__ , process->pid, this->trdid, count );
164#endif
165                    this->errno = EINVAL;
166                    return -1;
167        }
168
169        // move count bytes to device
170        nbytes = devfs_user_move( false,             // from buffer to device
171                                 file_xp,
172                                 vaddr,
173                                 count );
174    }
175    else  // not FILE and not DEV
176    {
177        nbytes = 0;
178        assert( false , "file type %d non supported\n", type );
179    }
180
181    if( nbytes != count )
182    {
183
184#if DEBUG_SYSCALLS_ERROR
185printk("\n[ERROR] in %s : thread[%x,‰x] cannot write data to file %d\n",
186__FUNCTION__ , process->pid, this->trdid, file_id );
187#endif
188        this->errno = error;
189        return -1;
190    }
191
192    // restore IRQs
193    hal_restore_irq( save_sr );
194
195    hal_fence();
196
197#if (DEBUG_SYS_WRITE || CONFIG_INSTRUMENTATION_SYSCALLS)
198uint64_t     tm_end = hal_get_cycles();
199#endif
200
201#if DEBUG_SYS_WRITE
202if( DEBUG_SYS_WRITE < tm_end )
203printk("\n[DBG] %s : thread[%x,%x] exit / cycle %d\n",
204__FUNCTION__, process->pid, this->trdid, (uint32_t)tm_end );
205#endif
206 
207#if CONFIG_INSTRUMENTATION_SYSCALLS
208hal_atomic_add( &syscalls_cumul_cost[SYS_WRITE] , tm_end - tm_start );
209hal_atomic_add( &syscalls_occurences[SYS_WRITE] , 1 );
210#endif
211
212#if (DEBUG_SYS_WRITE & 1)
213exit_sys_write = (uint32_t)tm_end;
214
215printk("\n***** timing to write a string *****\n"
216" - enter_sys_write          = %d / delta %d\n"
217" - enter_devfs_write        = %d / delta %d\n"
218" - enter_txt_write          = %d / delta %d\n"
219" - enter_chdev_cmd_write    = %d / delta %d\n"
220" - enter_chdev_server_write = %d / delta %d\n"
221" - enter_tty_cmd_write      = %d / delta %d\n"
222" - enter_tty_isr_write      = %d / delta %d\n"
223" - exit_tty_isr_write       = %d / delta %d\n"
224" - exit_tty_cmd_write       = %d / delta %d\n"
225" - exit_chdev_server_write  = %d / delta %d\n"
226" - exit_chdev_cmd_write     = %d / delta %d\n"
227" - exit_txt_write           = %d / delta %d\n"
228" - exit_devfs_write         = %d / delta %d\n"
229" - exit_sys_write           = %d / delta %d\n",
230enter_sys_write          , 0 ,
231enter_devfs_write        , enter_devfs_write        - enter_sys_write          ,
232enter_txt_write          , enter_txt_write          - enter_devfs_write        ,
233enter_chdev_cmd_write    , enter_chdev_cmd_write    - enter_txt_write          ,
234enter_chdev_server_write , enter_chdev_server_write - enter_chdev_cmd_write    ,
235enter_tty_cmd_write      , enter_tty_cmd_write      - enter_chdev_server_write ,
236enter_tty_isr_write      , enter_tty_isr_write      - enter_tty_cmd_write      ,
237exit_tty_isr_write       , exit_tty_isr_write       - enter_tty_isr_write      ,
238exit_tty_cmd_write       , exit_tty_cmd_write       - exit_tty_isr_write       ,
239exit_chdev_server_write  , exit_chdev_server_write  - exit_tty_cmd_write       ,
240exit_chdev_cmd_write     , exit_chdev_cmd_write     - exit_chdev_server_write  ,
241exit_txt_write           , exit_txt_write           - exit_chdev_cmd_write     ,
242exit_devfs_write         , exit_devfs_write         - exit_txt_write           ,
243exit_sys_write           , exit_sys_write           - exit_devfs_write         );
244#endif
245 
246        return nbytes;
247
248}  // end sys_write()
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