source: trunk/kernel/syscalls/sys_chdir.c @ 670

Last change on this file since 670 was 670, checked in by alain, 18 months 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: 4.0 KB
Line 
1/*
2 * sys_chdir.c - kernel function implementing the "chdir" 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 <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 || DEBUG_SYSCALLS_ERROR || 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
57if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
58printk("\n[ERROR] in %s : pathname too long / thread[%x,%x]\n",
59__FUNCTION__, process->pid, this->trdid );
60#endif
61        this->errno = EINVAL;
62        return -1;
63    }
64
65    // check pathname in user space
66    if( vmm_get_vseg( process, (intptr_t)pathname , &vseg ) )
67        {
68
69#if DEBUG_SYSCALLS_ERROR
70if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
71printk("\n[ERROR] in %s : user buffer unmapped %x for thread[%x,%x]\n",
72__FUNCTION__ , (intptr_t)pathname , process->pid, this->trdid );
73#endif
74                this->errno = EINVAL;
75        return -1;
76        }
77
78    // copy pathname in kernel space
79    hal_strcpy_from_uspace( XPTR( local_cxy , kbuf ),
80                            pathname,
81                            CONFIG_VFS_MAX_PATH_LENGTH );
82
83#if DEBUG_SYS_CHDIR
84if( DEBUG_SYS_CHDIR < (uint32_t)tm_start )
85printk("\n[%s] thread[%x,%x] enter for <%s> / cycle %d\n",
86__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_start );
87#endif
88
89    // compute root inode for path
90    if( kbuf[0] == '/' )                        // absolute path
91    {
92        // use extended pointer on VFS root inode
93        root_inode_xp = process->vfs_root_xp;
94    }
95    else                                        // relative path
96    {
97        // get cluster and local pointer on reference process
98        xptr_t      ref_xp  = process->ref_xp;
99        process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
100        cxy_t       ref_cxy = GET_CXY( ref_xp );
101
102        // use extended pointer on CWD inode
103        root_inode_xp = hal_remote_l64( XPTR( ref_cxy , &ref_ptr->cwd_xp ) );
104    }
105
106    // call the relevant VFS function
107    error = vfs_chdir( root_inode_xp , kbuf );
108
109    if( error )
110    {
111
112#if DEBUG_SYSCALLS_ERROR
113if( DEBUG_SYSCALLS_ERROR < (uint32_t)tm_start )
114printk("\n[ERROR] in %s / thread[%x,%x] : cannot change CWD\n",
115__FUNCTION__ , process->pid , this->trdid );
116#endif
117        this->errno = error;
118        return -1;
119    }
120
121    hal_fence();
122
123#if (DEBUG_SYS_CHDIR || CONFIG_INSTRUMENTATION_SYSCALLS)
124uint64_t     tm_end = hal_get_cycles();
125#endif
126
127#if DEBUG_SYS_CHDIR
128if( DEBUG_SYS_CHDIR < tm_end )
129printk("\n[%s] thread[%x,%x] exit  / cycle %d\n",
130__FUNCTION__, process->pid, this->trdid, (uint32_t)tm_end );
131#endif
132 
133#if CONFIG_INSTRUMENTATION_SYSCALLS
134hal_atomic_add( &syscalls_cumul_cost[SYS_CHDIR] , tm_end - tm_start );
135hal_atomic_add( &syscalls_occurences[SYS_CHDIR] , 1 );
136#endif
137
138    return 0;
139}
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