source: trunk/kernel/syscalls/sys_readdir.c @ 635

Last change on this file since 635 was 635, checked in by alain, 18 months ago

This version is a major evolution: The physical memory allocators,
defined in the kmem.c, ppm.c, and kcm.c files have been modified
to support remote accesses. The RPCs that were previously user
to allocate physical memory in a remote cluster have been removed.
This has been done to cure a dead-lock in case of concurrent page-faults.

This version 2.2 has been tested on a (4 clusters / 2 cores per cluster)
TSAR architecture, for both the "sort" and the "fft" applications.

File size: 4.3 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)
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 || 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 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
70printk("\n[ERROR] in %s / thread[%x,%x] : user buffer %x unmapped\n",
71__FUNCTION__ , process->pid , this->trdid, buffer );
72#endif
73                this->errno = EINVAL;
74                return -1;
75        }       
76
77    // get pointers on user_dir structure from dirp
78    dir_xp  = user_dir_from_ident( (intptr_t)dirp );
79    dir_ptr = GET_PTR( dir_xp );
80    dir_cxy = GET_CXY( dir_xp );
81
82    if( dir_xp == XPTR_NULL )
83        {
84
85#if DEBUG_SYSCALLS_ERROR
86printk("\n[ERROR] in %s / thread[%x,%x] : dirp %x not registered\n",
87__FUNCTION__ , process->pid , this->trdid, dirp );
88#endif
89                this->errno = EBADF;
90                return -1;
91        }       
92
93    // get "current" and "entries_nr" values from user_dir_t structure
94    current = hal_remote_l32( XPTR( dir_cxy , &dir_ptr->current ) );
95    entries = hal_remote_l32( XPTR( dir_cxy , &dir_ptr->entries ) );
96
97    // check "current" index
98    if( current >= entries )
99    {
100        this->errno = 0;
101        return -1;
102    }
103
104    // compute dirent pointer in user space
105    direntp = (struct dirent *)dirp + current;
106
107#if (DEBUG_SYS_READDIR & 1)
108if( DEBUG_SYS_READDIR < tm_start )
109printk("\n[%s] entries = %d / current = %d / direntp = %x\n",
110__FUNCTION__, entries, current, direntp );
111#endif
112
113    // copy dirent pointer to user buffer
114    hal_copy_to_uspace( local_cxy,
115                        &direntp,
116                        buffer,
117                        sizeof(void *) );
118
119    // update current index in user_dir structure
120    hal_remote_atomic_add( XPTR( dir_cxy , &dir_ptr->current ) , 1 );
121
122    hal_fence();
123
124#if (DEBUG_SYS_READDIR || CONFIG_INSTRUMENTATION_SYSCALLS)
125uint64_t     tm_end = hal_get_cycles();
126#endif
127
128#if DEBUG_SYS_READDIR
129if( DEBUG_SYS_READDIR < tm_end )
130printk("\n[%s] thread[%x,%x] exit / cycle %d\n",
131__FUNCTION__, process->pid, this->trdid, (uint32_t)tm_end );
132#endif
133 
134#if CONFIG_INSTRUMENTATION_SYSCALLS
135hal_atomic_add( &syscalls_cumul_cost[SYS_READDIR] , tm_end - tm_start );
136hal_atomic_add( &syscalls_occurences[SYS_READDIR] , 1 );
137#endif
138
139        return 0;
140
141}  // end sys_readdir()
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