source: trunk/kernel/syscalls/sys_readdir.c @ 684

Last change on this file since 684 was 670, checked in by alain, 4 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: 4.4 KB
Line 
1/*
2 * sys_readdir.c - Copy one entry from an open VFS directory to an user buffer.
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_uspace.h>
27#include <hal_vmm.h>
28#include <errno.h>
29#include <thread.h>
30#include <printk.h>
31#include <vfs.h>
32#include <process.h>
33#include <user_dir.h>
34#include <syscalls.h>
35#include <shared_syscalls.h>
36
37///////////////////////////////////////
38int sys_readdir( DIR            * dirp,
39                 struct dirent ** buffer )
40{
41    error_t         error;
42    vseg_t        * vseg;               // for user space checking of buffer
43    xptr_t          dir_xp;             // extended pointer on user_dir structure
44    user_dir_t    * dir_ptr;            // local pointer on user_dir structure
45    cxy_t           dir_cxy;            // user_dir stucture cluster identifier
46    struct dirent * direntp;            // dirent pointer in user space 
47    uint32_t        entries;            // total number of dirent entries
48    uint32_t        current;            // current dirent index
49
50        thread_t  * this    = CURRENT_THREAD;  // client thread
51        process_t * process = this->process;   // client process
52
53#if (DEBUG_SYS_READDIR || DEBUG_SYSCALLS_ERROR || CONFIG_INSTRUMENTATION_SYSCALLS)
54uint64_t     tm_start = hal_get_cycles();
55#endif
56
57#if DEBUG_SYS_READDIR
58if( DEBUG_SYS_READDIR < tm_start )
59printk("\n[%s] thread[%x,%x] enter / dirp %x / cycle %d\n",
60__FUNCTION__, process->pid, this->trdid, dirp, (uint32_t)tm_start );
61#endif
62 
63    // check dirent buffer in user space
64    error = vmm_get_vseg( process , (intptr_t)buffer, &vseg );
65
66        if( error )
67        {
68
69#if DEBUG_SYSCALLS_ERROR
70if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
71printk("\n[ERROR] in %s : thread[%x,%x] / dirent user buffer %x unmapped\n",
72__FUNCTION__ , process->pid , this->trdid, buffer );
73#endif
74                this->errno = EINVAL;
75                return -1;
76        }       
77
78    // get pointers on user_dir structure from dirp
79    dir_xp  = user_dir_from_ident( (intptr_t)dirp );
80    dir_ptr = GET_PTR( dir_xp );
81    dir_cxy = GET_CXY( dir_xp );
82
83    if( dir_xp == XPTR_NULL )
84        {
85
86#if DEBUG_SYSCALLS_ERROR
87if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
88printk("\n[ERROR] in %s : thread[%x,%x] / dirp %x not registered\n",
89__FUNCTION__ , process->pid , this->trdid, dirp );
90#endif
91                this->errno = EBADF;
92                return -1;
93        }       
94
95    // get "current" and "entries_nr" values from user_dir_t structure
96    current = hal_remote_l32( XPTR( dir_cxy , &dir_ptr->current ) );
97    entries = hal_remote_l32( XPTR( dir_cxy , &dir_ptr->entries ) );
98
99    // check "current" index
100    if( current >= entries )
101    {
102        this->errno = 0;
103        return -1;
104    }
105
106    // compute dirent pointer in user space
107    direntp = (struct dirent *)dirp + current;
108
109#if (DEBUG_SYS_READDIR & 1)
110if( DEBUG_SYS_READDIR < (uint32_t)tm_start )
111printk("\n[%s] entries = %d / current = %d / direntp = %x\n",
112__FUNCTION__, entries, current, direntp );
113#endif
114
115    // copy dirent pointer to user buffer
116    hal_copy_to_uspace( buffer,
117                        XPTR( local_cxy , &direntp ),
118                        sizeof(void *) );
119
120    // update current index in user_dir structure
121    hal_remote_atomic_add( XPTR( dir_cxy , &dir_ptr->current ) , 1 );
122
123    hal_fence();
124
125#if (DEBUG_SYS_READDIR || CONFIG_INSTRUMENTATION_SYSCALLS)
126uint64_t     tm_end = hal_get_cycles();
127#endif
128
129#if DEBUG_SYS_READDIR
130if( DEBUG_SYS_READDIR < (uint32_t)tm_end )
131printk("\n[%s] thread[%x,%x] exit / cycle %d\n",
132__FUNCTION__, process->pid, this->trdid, (uint32_t)tm_end );
133#endif
134 
135#if CONFIG_INSTRUMENTATION_SYSCALLS
136hal_atomic_add( &syscalls_cumul_cost[SYS_READDIR] , tm_end - tm_start );
137hal_atomic_add( &syscalls_occurences[SYS_READDIR] , 1 );
138#endif
139
140        return 0;
141
142}  // end sys_readdir()
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