source: trunk/kernel/syscalls/sys_chdir.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: 3.7 KB
Line 
1/*
2 * sys_chdir.c - kernel function implementing the "chdir" 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 <chdev.h>
27#include <rwlock.h>
28#include <vfs.h>
29#include <errno.h>
30#include <thread.h>
31#include <printk.h>
32#include <process.h>
33
34#include <syscalls.h>
35
36/////////////////////////////////
37int sys_chdir ( char * pathname )
38{
39    error_t   error;
40    vseg_t  * vseg; 
41    xptr_t    root_inode_xp;
42
43    char      kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
44
45    thread_t  * this    = CURRENT_THREAD;
46    process_t * process = this->process;
47
48#if (DEBUG_SYS_CHDIR || CONFIG_INSTRUMENTATION_SYSCALLS)
49uint64_t     tm_start = hal_get_cycles();
50#endif
51
52    // check pathname length
53    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
54    {
55
56#if DEBUG_SYSCALLS_ERROR
57printk("\n[ERROR] in %s : pathname too long / thread[%x,%x]\n",
58__FUNCTION__, process->pid, this->trdid );
59#endif
60        this->errno = EINVAL;
61        return -1;
62    }
63
64    // check pathname in user space
65    if( vmm_get_vseg( process, (intptr_t)pathname , &vseg ) )
66        {
67
68#if DEBUG_SYSCALLS_ERROR
69printk("\n[ERROR] in %s : user buffer unmapped %x for thread[%x,%x]\n",
70__FUNCTION__ , (intptr_t)pathname , process->pid, this->trdid );
71#endif
72                this->errno = EINVAL;
73        return -1;
74        }
75
76    // copy pathname in kernel space
77    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
78
79#if DEBUG_SYS_CHDIR
80if( DEBUG_SYS_CHDIR < tm_start )
81printk("\n[%s] thread[%x,%x] enter for <%s> / cycle %d\n",
82__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_start );
83#endif
84
85    // compute root inode for path
86    if( kbuf[0] == '/' )                        // absolute path
87    {
88        // use extended pointer on VFS root inode
89        root_inode_xp = process->vfs_root_xp;
90    }
91    else                                        // relative path
92    {
93        // get cluster and local pointer on reference process
94        xptr_t      ref_xp  = process->ref_xp;
95        process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
96        cxy_t       ref_cxy = GET_CXY( ref_xp );
97
98        // use extended pointer on CWD inode
99        root_inode_xp = hal_remote_l64( XPTR( ref_cxy , &ref_ptr->cwd_xp ) );
100    }
101
102    // call the relevant VFS function
103    error = vfs_chdir( root_inode_xp , kbuf );
104
105    if( error )
106    {
107
108#if DEBUG_SYSCALLS_ERROR
109printk("\n[ERROR] in %s / thread[%x,%x] : cannot change CWD\n",
110__FUNCTION__ , process->pid , this->trdid );
111#endif
112        this->errno = error;
113        return -1;
114    }
115
116    hal_fence();
117
118#if (DEBUG_SYS_CHDIR || CONFIG_INSTRUMENTATION_SYSCALLS)
119uint64_t     tm_end = hal_get_cycles();
120#endif
121
122#if DEBUG_SYS_CHDIR
123if( DEBUG_SYS_CHDIR < tm_end )
124printk("\n[%s] thread[%x,%x] exit  / cycle %d\n",
125__FUNCTION__, process->pid, this->trdid, (uint32_t)tm_end );
126#endif
127 
128#if CONFIG_INSTRUMENTATION_SYSCALLS
129hal_atomic_add( &syscalls_cumul_cost[SYS_CHDIR] , tm_end - tm_start );
130hal_atomic_add( &syscalls_occurences[SYS_CHDIR] , 1 );
131#endif
132
133    return 0;
134}
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