source: trunk/kernel/syscalls/sys_read.c@ 604

Last change on this file since 604 was 604, checked in by alain, 8 years ago

Improve the FAT32 file system to support cat, rm, cp commands.
File size: 9.5 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
37extern uint32_t enter_sys_read;
38extern uint32_t enter_devfs_read;
39extern uint32_t enter_txt_read;
40extern uint32_t enter_chdev_cmd_read;
41extern uint32_t enter_chdev_server_read;
42extern uint32_t enter_tty_cmd_read;
43extern uint32_t enter_tty_isr_read;
44extern uint32_t exit_tty_isr_read;
45extern uint32_t exit_tty_cmd_read;
46extern uint32_t exit_chdev_server_read;
47extern uint32_t exit_chdev_cmd_read;
48extern uint32_t exit_txt_read;
49extern uint32_t exit_devfs_read;
50extern uint32_t exit_sys_read;
51
52
53/////////////////////////////////
54int sys_read( uint32_t file_id,
55 void * vaddr,
56 uint32_t count )
57{
58 error_t error;
59 vseg_t * vseg; // required for user space checking
60 xptr_t file_xp; // remote file extended pointer
61 vfs_file_t * file_ptr; // remote file local pointer
62 cxy_t file_cxy; // remote file cluster identifier
63 uint32_t file_type; // file type
64 uint32_t file_offset; // current file offset
65 uint32_t file_attr; // file_attribute
66 vfs_inode_t * inode_ptr; // local pointer on associated inode
67 uint32_t nbytes; // number of bytes actually read
68 reg_t save_sr; // required to enable IRQs during syscall
69
70 thread_t * this = CURRENT_THREAD;
71 process_t * process = this->process;
72 xptr_t process_owner_xp = process->owner_xp;
73
74#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
75uint64_t tm_start = hal_get_cycles();
76#endif
77
78#if DEBUG_SYS_READ
79if( DEBUG_SYS_READ < tm_start )
80printk("\n[DBG] %s : thread[%x,%x] enter / vaddr %x / count %d / cycle %d\n",
81__FUNCTION__, process->pid, this->trdid, vaddr, count, (uint32_t)tm_start );
82#endif
83
84#if (DEBUG_SYS_READ & 1)
85enter_sys_read = (uint32_t)tm_start;
86#endif
87
88 // check file_id argument
89 if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
90 {
91
92#if DEBUG_SYSCALLS_ERROR
93printk("\n[ERROR] in %s : thread[%x,%x] illegal file descriptor index %d\n",
94__FUNCTION__ , process->pid, this->trdid, file_id );
95#endif
96 this->errno = EBADFD;
97 return -1;
98 }
99
100 // check user buffer in user space
101 error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
102
103 if ( error )
104 {
105
106#if DEBUG_SYSCALLS_ERROR
107printk("\n[ERROR] in %s : thread[%x,%x] user buffer unmapped %x\n",
108__FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr );
109vmm_display( process , false );
110#endif
111 this->errno = EINVAL;
112 return -1;
113 }
114
115 // get extended pointer on remote file descriptor
116 file_xp = process_fd_get_xptr( process , file_id );
117
118 if( file_xp == XPTR_NULL )
119 {
120
121#if DEBUG_SYSCALLS_ERROR
122printk("\n[ERROR] in %s : thread[%x,%x] undefined fd_id %d\n",
123__FUNCTION__, process->pid, this->trdid, file_id );
124#endif
125 this->errno = EBADFD;
126 return -1;
127 }
128
129 // get file descriptor cluster and local pointer
130 file_ptr = GET_PTR( file_xp );
131 file_cxy = GET_CXY( file_xp );
132
133 // get file type, offset, attributes and associated inode
134 file_type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
135 file_offset = hal_remote_l32( XPTR( file_cxy , &file_ptr->offset ) );
136 inode_ptr = hal_remote_lpt( XPTR( file_cxy , &file_ptr->inode ) );
137 file_attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
138
139 // enable IRQs
140 hal_enable_irq( &save_sr );
141
142 // action depend on file type
143 if( file_type == INODE_TYPE_FILE ) // read from file mapper
144 {
145 // check file readable
146 if( (file_attr & FD_ATTR_READ_ENABLE) == 0 )
147 {
148
149#if DEBUG_SYSCALLS_ERROR
150printk("\n[ERROR] in %s : thread[%x,%x] file %d not readable\n",
151__FUNCTION__, process->pid, this->trdid, file_id );
152#endif
153 hal_restore_irq( save_sr );
154 this->errno = EBADFD;
155 return -1;
156 }
157
158 // move count bytes from mapper
159 nbytes = vfs_user_move( true, // from mapper to buffer
160 file_xp,
161 vaddr,
162 count );
163 if( nbytes != count )
164 {
165
166#if DEBUG_SYSCALLS_ERROR
167printk("\n[ERROR] in %s : thread[%x,‰x] cannot read %d bytes from file %d\n",
168__FUNCTION__, process->pid, this->trdid, count, file_id );
169#endif
170 this->errno = EIO;
171 hal_restore_irq( save_sr );
172 return -1;
173 }
174 }
175 else if( file_type == INODE_TYPE_DEV ) // read from TXT device
176 {
177 // get cluster and pointers on TXT_RX chdev
178 xptr_t chdev_xp = chdev_from_file( file_xp );
179 cxy_t chdev_cxy = GET_CXY( chdev_xp );
180 chdev_t * chdev_ptr = GET_PTR( chdev_xp );
181
182 volatile xptr_t txt_owner_xp;
183 uint32_t iter = 0;
184
185 while( 1 )
186 {
187 // extended pointer on TXT owner process
188 txt_owner_xp = hal_remote_l64( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) );
189
190 // check TXT_RX ownership
191 if ( process_owner_xp != txt_owner_xp )
192 {
193 if( (iter & 0xFFF) == 0 )
194 printk("\n[WARNING] in %s : thread[%x,%x] wait TXT_RX / cycle %d\n",
195 __FUNCTION__, process->pid, this->trdid, (uint32_t)hal_get_cycles() );
196
197 // deschedule without blocking
198 sched_yield( "wait TXT_RX ownership" );
199
200 iter++;
201 }
202 else
203 {
204 break;
205 }
206 }
207
208 // move count bytes from device
209 nbytes = devfs_user_move( true, // from device to buffer
210 file_xp,
211 vaddr,
212 count );
213 if( nbytes != count )
214 {
215
216#if DEBUG_SYSCALLS_ERROR
217printk("\n[ERROR] in %s : thread[%x,‰x] cannot read data from file %d\n",
218__FUNCTION__, process->pid, this->trdid, file_id );
219#endif
220 this->errno = EIO;
221 hal_restore_irq( save_sr );
222 return -1;
223 }
224 }
225 else // not FILE and not DEV
226 {
227
228#if DEBUG_SYSCALLS_ERROR
229printk("\n[ERROR] in %s : thread[%x,%x] / illegal inode type %\n",
230__FUNCTION__, vfs_inode_type_str( file_type ) );
231#endif
232 this->errno = EBADFD;
233 hal_restore_irq( save_sr );
234 return -1;
235 }
236
237 // restore IRQs
238 hal_restore_irq( save_sr );
239
240 hal_fence();
241
242#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
243uint64_t tm_end = hal_get_cycles();
244#endif
245
246#if DEBUG_SYS_READ
247if( DEBUG_SYS_READ < tm_end )
248printk("\n[DBG] %s : thread[%x,%x] exit / cycle %d\n",
249__FUNCTION__ , process->pid, this->trdid, (uint32_t)tm_end );
250#endif
251
252#if CONFIG_INSTRUMENTATION_SYSCALLS
253hal_atomic_add( &syscalls_cumul_cost[SYS_READ] , tm_end - tm_start );
254hal_atomic_add( &syscalls_occurences[SYS_READ] , 1 );
255#endif
256
257#if (DEBUG_SYS_READ & 1)
258exit_sys_read = (uint32_t)tm_end;
259
260printk("\n***** timing to read one character *****\n"
261" - enter_sys_read = %d / delta %d\n"
262" - enter_devfs_read = %d / delta %d\n"
263" - enter_txt_read = %d / delta %d\n"
264" - enter_chdev_cmd_read = %d / delta %d\n"
265" - enter_chdev_server_read = %d / delta %d\n"
266" - enter_tty_cmd_read = %d / delta %d\n"
267" - enter_tty_isr_read = %d / delta %d\n"
268" - exit_tty_isr_read = %d / delta %d\n"
269" - exit_tty_cmd_read = %d / delta %d\n"
270" - exit_chdev_server_read = %d / delta %d\n"
271" - exit_chdev_cmd_read = %d / delta %d\n"
272" - exit_txt_read = %d / delta %d\n"
273" - exit_devfs_read = %d / delta %d\n"
274" - exit_sys_read = %d / delta %d\n",
275enter_sys_read , 0 ,
276enter_devfs_read , enter_devfs_read - enter_sys_read ,
277enter_txt_read , enter_txt_read - enter_devfs_read ,
278enter_chdev_cmd_read , enter_chdev_cmd_read - enter_txt_read ,
279enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read ,
280enter_tty_cmd_read , enter_tty_cmd_read - enter_chdev_server_read ,
281enter_tty_isr_read , enter_tty_isr_read - enter_tty_cmd_read ,
282exit_tty_isr_read , exit_tty_isr_read - enter_tty_isr_read ,
283exit_tty_cmd_read , exit_tty_cmd_read - exit_tty_isr_read ,
284exit_chdev_server_read , exit_chdev_server_read - exit_tty_cmd_read ,
285exit_chdev_cmd_read , exit_chdev_cmd_read - exit_chdev_server_read ,
286exit_txt_read , exit_txt_read - exit_chdev_cmd_read ,
287exit_devfs_read , exit_devfs_read - exit_txt_read ,
288exit_sys_read , exit_sys_read - exit_devfs_read );
289#endif
290
291 return nbytes;
292
293} // end sys_read()
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