source: trunk/kernel/syscalls/sys_stat.c @ 610

Last change on this file since 610 was 610, checked in by alain, 3 years ago

Fix several bugs in VFS to support the following
ksh commandis : cp, mv, rm, mkdir, cd, pwd

File size: 4.2 KB
Line 
1/*
2 * sys_stat.c - kernel function implementing the "stat" syscall.
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 <hal_kernel_types.h>
25#include <hal_uspace.h>
26#include <hal_special.h>
27#include <errno.h>
28#include <thread.h>
29#include <printk.h>
30#include <vfs.h>
31#include <vmm.h>
32#include <process.h>
33
34#include <syscalls.h>
35
36/////////////////////////////////////
37int sys_stat( char        * pathname,
38              struct stat * u_stat )
39{
40    error_t       error;
41    vseg_t      * vseg;                   // for user space checking
42    struct stat   k_stat;                 // in kernel space
43    xptr_t        root_inode_xp;          // extended pointer on path root inode
44
45    char          kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
46       
47        thread_t  * this    = CURRENT_THREAD;
48        process_t * process = this->process;
49
50#if (DEBUG_SYS_STAT || CONFIG_INSTRUMENTATION_SYSCALLS)
51uint64_t     tm_start = hal_get_cycles();
52#endif
53
54    // check stat structure in user space
55    error = vmm_get_vseg( process , (intptr_t)u_stat , &vseg );
56
57        if( error )
58        {
59
60#if DEBUG_SYSCALLS_ERROR
61printk("\n[ERROR] in %s / thread[%x,%x] : stat structure %x unmapped\n",
62__FUNCTION__ , process->pid , this->trdid, u_stat );
63vmm_display( process , false );
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( u_stat , &k_stat , sizeof(struct stat) );
124
125    hal_fence();
126
127#if (DEBUG_SYS_STAT || CONFIG_INSTRUMENTATION_SYSCALLS)
128uint64_t     tm_end = hal_get_cycles();
129#endif
130
131#if DEBUG_SYS_STAT
132if( DEBUG_SYS_STAT < tm_end )
133printk("\n[%s] thread[%x,%x] exit for file <%s> / size %d / mode %d / cycle %d\n",
134__FUNCTION__, process->pid, this->trdid, kbuf,
135k_stat.st_size, k_stat.st_mode, (uint32_t)tm_end );
136#endif
137 
138#if CONFIG_INSTRUMENTATION_SYSCALLS
139hal_atomic_add( &syscalls_cumul_cost[SYS_STAT] , tm_end - tm_start );
140hal_atomic_add( &syscalls_occurences[SYS_STAT] , 1 );
141#endif
142
143        return 0;
144
145}  // end sys_stat()
146
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