source: trunk/kernel/syscalls/sys_stat.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_stat.c - kernel function implementing the "stat" syscall.
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 <hal_kernel_types.h>
25#include <hal_uspace.h>
26#include <hal_vmm.h>
27#include <hal_special.h>
28#include <errno.h>
29#include <thread.h>
30#include <printk.h>
31#include <vfs.h>
32#include <vmm.h>
33#include <process.h>
34
35#include <syscalls.h>
36
37/////////////////////////////////////
38int sys_stat( char        * pathname,
39              struct stat * u_stat )
40{
41    error_t       error;
42    vseg_t      * vseg;                   // for user space checking
43    struct stat   k_stat;                 // in kernel space
44    xptr_t        root_inode_xp;          // extended pointer on path root inode
45
46    char          kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
47       
48        thread_t  * this    = CURRENT_THREAD;
49        process_t * process = this->process;
50
51#if (DEBUG_SYS_STAT || CONFIG_INSTRUMENTATION_SYSCALLS)
52uint64_t     tm_start = hal_get_cycles();
53#endif
54
55    // check stat structure in user space
56    error = vmm_get_vseg( process , (intptr_t)u_stat , &vseg );
57
58        if( error )
59        {
60
61#if DEBUG_SYSCALLS_ERROR
62printk("\n[ERROR] in %s / thread[%x,%x] : stat structure %x unmapped\n",
63__FUNCTION__ , process->pid , this->trdid, u_stat );
64#endif
65                this->errno = EINVAL;
66                return -1;
67        }       
68
69    // check pathname length
70    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
71    {
72
73#if DEBUG_SYSCALLS_ERROR
74printk("\n[ERROR] in %s / thread[%x,%x] : pathname too long\n",
75 __FUNCTION__ , process->pid , this->trdid );
76#endif
77        this->errno = ENFILE;
78        return -1;
79    }
80
81    // copy pathname in kernel space
82    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
83
84#if DEBUG_SYS_STAT
85if( DEBUG_SYS_STAT < tm_start )
86printk("\n[%s] thread[%x,%x] enter for file <%s> / cycle %d\n",
87__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_start );
88#endif
89
90    // compute root inode for path
91    if( kbuf[0] == '/' )                        // absolute path
92    {
93        // use extended pointer on VFS root inode
94        root_inode_xp = process->vfs_root_xp;
95    }
96    else                                        // relative path
97    {
98        // get cluster and local pointer on reference process
99        xptr_t      ref_xp  = process->ref_xp;
100        process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
101        cxy_t       ref_cxy = GET_CXY( ref_xp );
102
103        // use extended pointer on CWD inode
104        root_inode_xp = hal_remote_l64( XPTR( ref_cxy , &ref_ptr->cwd_xp ) );
105    }
106
107    // call the relevant VFS function
108    error = vfs_stat( root_inode_xp,
109                      kbuf,
110                      &k_stat ); 
111    if( error )
112        {
113
114#if DEBUG_SYSCALLS_ERROR
115printk("\n[ERROR] in %s / thread[%x,%x] : cannot get stats for inode <%s>\n",
116__FUNCTION__ , process->pid , this->trdid , pathname );
117#endif
118                this->errno = ENFILE;
119                return -1;
120        }
121   
122    // copy k_stat to u_stat
123    hal_copy_to_uspace( local_cxy,
124                        &k_stat,
125                        u_stat,
126                        sizeof(struct stat) );
127
128    hal_fence();
129
130#if (DEBUG_SYS_STAT || CONFIG_INSTRUMENTATION_SYSCALLS)
131uint64_t     tm_end = hal_get_cycles();
132#endif
133
134#if DEBUG_SYS_STAT
135if( DEBUG_SYS_STAT < tm_end )
136printk("\n[%s] thread[%x,%x] exit for file <%s> / size %d / mode %d / cycle %d\n",
137__FUNCTION__, process->pid, this->trdid, kbuf,
138k_stat.st_size, k_stat.st_mode, (uint32_t)tm_end );
139#endif
140 
141#if CONFIG_INSTRUMENTATION_SYSCALLS
142hal_atomic_add( &syscalls_cumul_cost[SYS_STAT] , tm_end - tm_start );
143hal_atomic_add( &syscalls_occurences[SYS_STAT] , 1 );
144#endif
145
146        return 0;
147
148}  // end sys_stat()
149
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