source: trunk/kernel/syscalls/sys_read.c@ 670

Last change on this file since 670 was 670, checked in by alain, 6 years ago

1) Introduce up to 4 command lines arguments in the KSH "load" command.
These arguments are transfered to the user process through the
argc/argv mechanism, using the user space "args" vseg.

2) Introduce the named and anonymous "pipes", for inter-process communication
through the pipe() and mkfifo() syscalls.

3) Introduce the "chat" application to validate the two above mechanisms.

4) Improve printk() and assert() fonctions in printk.c.
File size: 10.0 KB
Line 
1/*
2 * sys_read.c - Kernel function implementing the "read" system call.
3 *
4 * Author Alain Greiner (2016,2017,2018,2019,2020)
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_vmm.h>
27#include <hal_uspace.h>
28#include <hal_irqmask.h>
29#include <hal_special.h>
30#include <errno.h>
31#include <vfs.h>
32#include <vmm.h>
33#include <thread.h>
34#include <printk.h>
35#include <pipe.h>
36#include <process.h>
37
38
39extern uint32_t enter_sys_read;
40extern uint32_t enter_devfs_read;
41extern uint32_t enter_txt_read;
42extern uint32_t enter_chdev_cmd_read;
43extern uint32_t enter_chdev_server_read;
44extern uint32_t enter_tty_cmd_read;
45extern uint32_t enter_tty_isr_read;
46extern uint32_t exit_tty_isr_read;
47extern uint32_t exit_tty_cmd_read;
48extern uint32_t exit_chdev_server_read;
49extern uint32_t exit_chdev_cmd_read;
50extern uint32_t exit_txt_read;
51extern uint32_t exit_devfs_read;
52extern uint32_t exit_sys_read;
53
54
55/////////////////////////////////
56int sys_read( uint32_t file_id,
57 void * vaddr,
58 uint32_t count )
59{
60 error_t error;
61 vseg_t * vseg; // required for user space checking
62 xptr_t file_xp; // remote file extended pointer
63 vfs_file_t * file_ptr; // remote file local pointer
64 cxy_t file_cxy; // remote file cluster identifier
65 uint32_t file_type; // file type
66 uint32_t file_offset; // file offset
67 uint32_t file_attr; // file attributes
68 vfs_inode_t * inode_ptr; // local pointer on file inode
69 uint32_t nbytes; // number of bytes actually read
70 reg_t save_sr; // required to enable IRQs during syscall
71
72 thread_t * this = CURRENT_THREAD;
73 process_t * process = this->process;
74 xptr_t process_owner_xp = process->owner_xp;
75
76#if DEBUG_SYS_READ || DEBUG_SYSCALLS_ERROR || CONFIG_INSTRUMENTATION_SYSCALLS
77uint64_t tm_start = hal_get_cycles();
78#endif
79
80#if DEBUG_SYS_READ
81if( DEBUG_SYS_READ < tm_start )
82printk("\n[%s] thread[%x,%x] enter / vaddr %x / count %d / cycle %d\n",
83__FUNCTION__, process->pid, this->trdid, vaddr, count, (uint32_t)tm_start );
84#endif
85
86#if (DEBUG_SYS_READ & 1)
87enter_sys_read = (uint32_t)tm_start;
88#endif
89
90 // check file_id argument
91 if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
92 {
93
94#if DEBUG_SYSCALLS_ERROR
95if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
96printk("\n[ERROR] in %s : thread[%x,%x] / illegal file descriptor index %d\n",
97__FUNCTION__ , process->pid, this->trdid, file_id );
98#endif
99 this->errno = EBADFD;
100 return -1;
101 }
102
103 // check user buffer in user space
104 error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
105
106 if ( error )
107 {
108
109#if DEBUG_SYSCALLS_ERROR
110if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
111printk("\n[ERROR] in %s : thread[%x,%x] / user buffer unmapped %x\n",
112__FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr );
113#endif
114 this->errno = EINVAL;
115 return -1;
116 }
117
118 // get extended pointer on remote file descriptor
119 file_xp = process_fd_get_xptr_from_local( process , file_id );
120
121 if( file_xp == XPTR_NULL )
122 {
123
124#if DEBUG_SYSCALLS_ERROR
125if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
126printk("\n[ERROR] in %s : thread[%x,%x] / undefined fd_id %d\n",
127__FUNCTION__, process->pid, this->trdid, file_id );
128#endif
129 this->errno = EBADFD;
130 return -1;
131 }
132
133 // get file descriptor cluster and local pointer
134 file_ptr = GET_PTR( file_xp );
135 file_cxy = GET_CXY( file_xp );
136
137 // get inode, file type, offset and attributes
138 inode_ptr = hal_remote_lpt( XPTR( file_cxy , &file_ptr->inode ) );
139 file_type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
140 file_offset = hal_remote_l32( XPTR( file_cxy , &file_ptr->offset ) );
141 file_attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
142
143 // enable IRQs
144 hal_enable_irq( &save_sr );
145
146 // check file readable
147 if( (file_attr & FD_ATTR_READ_ENABLE) == 0 )
148 {
149
150#if DEBUG_SYSCALLS_ERROR
151if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
152printk("\n[ERROR] in %s : thread[%x,%x] / file %d not readable\n",
153__FUNCTION__, process->pid, this->trdid, file_id );
154#endif
155 hal_restore_irq( save_sr );
156 this->errno = EBADFD;
157 return -1;
158 }
159
160 // action depend on file type:
161 if( file_type == FILE_TYPE_REG ) // read from mapper
162 {
163 // try to move count bytes from mapper
164 nbytes = vfs_user_move( true, // from mapper
165 file_xp,
166 vaddr,
167 count );
168 }
169 else if( file_type == FILE_TYPE_DEV ) // read from TXT device
170 {
171 // get cluster and pointers on TXT_RX chdev
172 xptr_t chdev_xp = chdev_from_file( file_xp );
173 cxy_t chdev_cxy = GET_CXY( chdev_xp );
174 chdev_t * chdev_ptr = GET_PTR( chdev_xp );
175
176 volatile xptr_t txt_owner_xp;
177 uint32_t iter = 0;
178
179 while( 1 )
180 {
181 // extended pointer on TXT owner process
182 txt_owner_xp = hal_remote_l64( XPTR( chdev_cxy ,
183 &chdev_ptr->ext.txt.owner_xp ) );
184 // wait for TXT_RX ownership
185 if ( process_owner_xp != txt_owner_xp )
186 {
187 if( (iter & 0xFFF) == 0 )
188 printk("\n[WARNING] in %s : thread[%x,%x] wait TXT_RX / cycle %d\n",
189 __FUNCTION__, process->pid, this->trdid, (uint32_t)hal_get_cycles() );
190
191 // deschedule without blocking
192 sched_yield( "wait TXT_RX ownership" );
193
194 iter++;
195 }
196 else
197 {
198 break;
199 }
200 }
201
202 // try to move count bytes from TXT device
203 nbytes = devfs_user_move( true, // from device
204 file_xp,
205 vaddr,
206 count );
207 }
208 else if( (file_type == FILE_TYPE_PIPE) ||
209 (file_type == FILE_TYPE_FIFO) ) // read from pipe
210 {
211 // try to move count bytes from pipe
212 nbytes = pipe_user_move( true, // from pipe
213 file_xp,
214 vaddr,
215 count );
216 }
217 else // unsupported type
218 {
219
220#if DEBUG_SYSCALLS_ERROR
221if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
222printk("\n[ERROR] in %s : thread[%x,%x] / unsupported inode type %d\n",
223__FUNCTION__, vfs_inode_type_str( file_type ) );
224#endif
225 this->errno = EBADFD;
226 hal_restore_irq( save_sr );
227 return -1;
228 }
229
230 // check error
231 if( nbytes == 0xFFFFFFFF )
232 {
233
234#if DEBUG_SYSCALLS_ERROR
235if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
236printk("\n[ERROR] in %s : thread[%x,‰x] cannot read data from file %d\n",
237__FUNCTION__, process->pid, this->trdid, file_id );
238#endif
239 this->errno = EIO;
240 hal_restore_irq( save_sr );
241 return -1;
242 }
243
244 // restore IRQs
245 hal_restore_irq( save_sr );
246
247 hal_fence();
248
249#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
250uint64_t tm_end = hal_get_cycles();
251#endif
252
253#if DEBUG_SYS_READ
254if( DEBUG_SYS_READ < tm_end )
255printk("\n[%s] thread[%x,%x] exit / cycle %d\n",
256__FUNCTION__ , process->pid, this->trdid, (uint32_t)tm_end );
257#endif
258
259#if CONFIG_INSTRUMENTATION_SYSCALLS
260hal_atomic_add( &syscalls_cumul_cost[SYS_READ] , tm_end - tm_start );
261hal_atomic_add( &syscalls_occurences[SYS_READ] , 1 );
262#endif
263
264#if (DEBUG_SYS_READ & 1)
265exit_sys_read = (uint32_t)tm_end;
266
267printk("\n***** timing to read one character *****\n"
268" - enter_sys_read = %d / delta %d\n"
269" - enter_devfs_read = %d / delta %d\n"
270" - enter_txt_read = %d / delta %d\n"
271" - enter_chdev_cmd_read = %d / delta %d\n"
272" - enter_chdev_server_read = %d / delta %d\n"
273" - enter_tty_cmd_read = %d / delta %d\n"
274" - enter_tty_isr_read = %d / delta %d\n"
275" - exit_tty_isr_read = %d / delta %d\n"
276" - exit_tty_cmd_read = %d / delta %d\n"
277" - exit_chdev_server_read = %d / delta %d\n"
278" - exit_chdev_cmd_read = %d / delta %d\n"
279" - exit_txt_read = %d / delta %d\n"
280" - exit_devfs_read = %d / delta %d\n"
281" - exit_sys_read = %d / delta %d\n",
282enter_sys_read , 0 ,
283enter_devfs_read , enter_devfs_read - enter_sys_read ,
284enter_txt_read , enter_txt_read - enter_devfs_read ,
285enter_chdev_cmd_read , enter_chdev_cmd_read - enter_txt_read ,
286enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read ,
287enter_tty_cmd_read , enter_tty_cmd_read - enter_chdev_server_read ,
288enter_tty_isr_read , enter_tty_isr_read - enter_tty_cmd_read ,
289exit_tty_isr_read , exit_tty_isr_read - enter_tty_isr_read ,
290exit_tty_cmd_read , exit_tty_cmd_read - exit_tty_isr_read ,
291exit_chdev_server_read , exit_chdev_server_read - exit_tty_cmd_read ,
292exit_chdev_cmd_read , exit_chdev_cmd_read - exit_chdev_server_read ,
293exit_txt_read , exit_txt_read - exit_chdev_cmd_read ,
294exit_devfs_read , exit_devfs_read - exit_txt_read ,
295exit_sys_read , exit_sys_read - exit_devfs_read );
296#endif
297
298 return nbytes;
299
300} // end sys_read()
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