source: trunk/kernel/syscalls/sys_read.c @ 458

Last change on this file since 458 was 457, checked in by alain, 6 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: 8.6 KB
Line 
1/*
2 * sys_read.c - read bytes from a file
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// TODO: concurrent user page(s) munmap need to be handled [AG]
37
38extern uint32_t enter_sys_read;
39extern uint32_t enter_devfs_read;
40extern uint32_t enter_txt_read;
41extern uint32_t enter_chdev_cmd_read;
42extern uint32_t enter_chdev_server_read;
43extern uint32_t enter_tty_cmd_read;
44extern uint32_t enter_tty_isr_read;
45extern uint32_t exit_tty_isr_read;
46extern uint32_t exit_tty_cmd_read;
47extern uint32_t exit_chdev_server_read;
48extern uint32_t exit_chdev_cmd_read;
49extern uint32_t exit_txt_read;
50extern uint32_t exit_devfs_read;
51extern uint32_t exit_sys_read;
52
53
54/////////////////////////////////
55int sys_read( uint32_t   file_id,
56              void     * vaddr,
57              uint32_t   count )
58{
59    error_t      error;
60    vseg_t     * vseg;        // required for user space checking
61        xptr_t       file_xp;     // remote file extended pointer
62    uint32_t     nbytes;      // number of bytes actually read
63    reg_t        save_sr;     // required to enable IRQs during syscall
64
65        thread_t  *  this             = CURRENT_THREAD;
66        process_t *  process          = this->process;
67    xptr_t       process_owner_xp = process->owner_xp;
68 
69#if DEBUG_SYS_READ
70uint64_t     tm_start;
71uint64_t     tm_end;
72tm_start = hal_get_cycles();
73if( DEBUG_SYS_READ < tm_start )
74printk("\n[DBG] %s : thread %x enter / process %x / vaddr = %x / count %d / cycle %d\n",
75__FUNCTION__, this, process->pid, vaddr, count, (uint32_t)tm_start );
76#endif
77
78#if (DEBUG_SYS_READ & 1)
79enter_sys_read = (uint32_t)tm_start;
80#endif
81
82    // check file_id argument
83        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
84        {
85
86#if DEBUG_SYSCALLS_ERROR
87printk("\n[ERROR] in %s : illegal file descriptor index = %d\n", __FUNCTION__ , 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 : user buffer unmapped %x / thread %x / process %x\n",
101__FUNCTION__ , (intptr_t)vaddr, this->trdid, process->pid );
102vmm_display( process , false );
103#endif
104                this->errno = EINVAL;
105                return -1;
106    }
107
108    // enable IRQs
109    hal_enable_irq( &save_sr );
110
111    // get extended pointer on remote file descriptor
112    file_xp = process_fd_get_xptr( process , file_id );
113
114    if( file_xp == XPTR_NULL )
115    {
116
117#if DEBUG_SYSCALLS_ERROR
118printk("\n[ERROR] in %s : undefined fd_id %d in process %x\n",
119__FUNCTION__ , file_id , process->pid );
120#endif
121        this->errno = EBADFD;
122        return -1;
123    }
124
125    // get file descriptor cluster and local pointer
126    vfs_file_t * file_ptr = GET_PTR( file_xp );
127    cxy_t        file_cxy = GET_CXY( file_xp );
128
129    // check file readable
130    uint32_t attr = hal_remote_lw( XPTR( file_cxy , &file_ptr->attr ) );
131    if( (attr & FD_ATTR_READ_ENABLE) == 0 )
132        {
133
134#if DEBUG_SYSCALLS_ERROR
135printk("\n[ERROR] in %s : file %d not readable in process %x\n",
136__FUNCTION__ , file_id , process->pid );
137#endif
138                this->errno = EBADFD;
139                return -1;
140        }
141   
142    // get file type
143    vfs_inode_type_t type = hal_remote_lw( XPTR( file_cxy , &file_ptr->type ) );
144
145    // action depend on file type
146    if( type == INODE_TYPE_FILE )      // check file readable & read from mapper
147    {
148        // check file readable
149        uint32_t attr = hal_remote_lw( XPTR( file_cxy , &file_ptr->attr ) );
150
151        if( (attr & FD_ATTR_READ_ENABLE) == 0 )
152            {
153
154#if DEBUG_SYSCALLS_ERROR
155printk("\n[ERROR] in %s : file %d not readable in process %x\n",
156__FUNCTION__ , file_id , process->pid );
157#endif
158                    this->errno = EBADFD;
159                    return -1;
160            }
161
162        // move count bytes from mapper
163        nbytes = vfs_user_move( true,               // from mapper to buffer
164                                file_xp,
165                                vaddr, 
166                                count );
167    }
168    else if( type == INODE_TYPE_DEV )  // check ownership & read from device
169    {
170        // get cluster and pointers on TXT_RX chdev
171        xptr_t    chdev_xp  = chdev_from_file( file_xp );
172        cxy_t     chdev_cxy = GET_CXY( chdev_xp );
173        chdev_t * chdev_ptr = GET_PTR( chdev_xp );
174
175        volatile xptr_t    txt_owner_xp;   
176        uint32_t           iter = 0;
177
178        while( 1 )
179        {
180            // extended pointer on TXT owner process
181            txt_owner_xp  = hal_remote_lwd( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) );
182
183            // check TXT_RX ownership
184            if ( process_owner_xp != txt_owner_xp )
185            {
186                if( (iter & 0xFFF) == 0 )
187                printk("\n[WARNING] in %s : thread %x in process %x wait TXT_RX / cycle %d\n",
188                __FUNCTION__, this->trdid, process->pid, (uint32_t)hal_get_cycles() );
189
190                // deschedule without blocking
191                sched_yield( "wait TXT_RX ownership" );
192
193                iter++;
194            }
195            else
196            {
197                break;
198            }
199        }
200
201        // move count bytes from device
202        nbytes = devfs_user_move( true,             // from device to buffer
203                                  file_xp,
204                                  vaddr,
205                                  count );
206
207    }
208    else
209    {
210        nbytes = 0;
211        assert( false , __FUNCTION__ , "file type %d non supported yet\n", type );
212    }
213
214    if( nbytes != count )
215    {
216
217#if DEBUG_SYSCALLS_ERROR
218printk("\n[ERROR] in %s cannot read data from file %d in process %x\n",
219__FUNCTION__ , file_id , process->pid );
220#endif
221        this->errno = error;
222        return -1;
223    }
224
225    // restore IRQs
226    hal_restore_irq( save_sr );
227
228    hal_fence();
229
230#if DEBUG_SYS_READ
231tm_end = hal_get_cycles();
232if( DEBUG_SYS_READ < tm_end )
233printk("\n[DBG] %s : thread %x exit / process %x / cycle %d\n"
234"nbytes = %d / file_id = %d / cost = %d\n",
235__FUNCTION__ , this, process->pid,
236(uint32_t)tm_start , nbytes , file_id , (uint32_t)(tm_end - tm_start) );
237#endif
238
239#if (DEBUG_SYS_READ & 1)
240exit_sys_read = (uint32_t)tm_end;
241
242printk("\n***** timing to read one character *****\n"
243" - enter_sys_read          = %d / delta %d\n"
244" - enter_devfs_read        = %d / delta %d\n"
245" - enter_txt_read          = %d / delta %d\n"
246" - enter_chdev_cmd_read    = %d / delta %d\n"
247" - enter_chdev_server_read = %d / delta %d\n"
248" - enter_tty_cmd_read      = %d / delta %d\n"
249" - enter_tty_isr_read      = %d / delta %d\n"
250" - exit_tty_isr_read       = %d / delta %d\n"
251" - exit_tty_cmd_read       = %d / delta %d\n"
252" - exit_chdev_server_read  = %d / delta %d\n"
253" - exit_chdev_cmd_read     = %d / delta %d\n"
254" - exit_txt_read           = %d / delta %d\n"
255" - exit_devfs_read         = %d / delta %d\n"
256" - exit_sys_read           = %d / delta %d\n",
257enter_sys_read          , 0 ,
258enter_devfs_read        , enter_devfs_read        - enter_sys_read          ,
259enter_txt_read          , enter_txt_read          - enter_devfs_read        ,
260enter_chdev_cmd_read    , enter_chdev_cmd_read    - enter_txt_read          ,
261enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read    ,
262enter_tty_cmd_read      , enter_tty_cmd_read      - enter_chdev_server_read ,
263enter_tty_isr_read      , enter_tty_isr_read      - enter_tty_cmd_read      ,
264exit_tty_isr_read       , exit_tty_isr_read       - enter_tty_isr_read      ,
265exit_tty_cmd_read       , exit_tty_cmd_read       - exit_tty_isr_read       ,
266exit_chdev_server_read  , exit_chdev_server_read  - exit_tty_cmd_read       ,
267exit_chdev_cmd_read     , exit_chdev_cmd_read     - exit_chdev_server_read  ,
268exit_txt_read           , exit_txt_read           - exit_chdev_cmd_read     ,
269exit_devfs_read         , exit_devfs_read         - exit_txt_read           ,
270exit_sys_read           , exit_sys_read           - exit_devfs_read         );
271#endif
272 
273        return nbytes;
274
275}  // end sys_read()
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