source: trunk/kernel/syscalls/sys_unlink.c @ 617

Last change on this file since 617 was 610, checked in by alain, 6 years ago

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

File size: 3.4 KB
Line 
1/*
2 * sys_unlink.c - unlink a file or directorya from VFS
3 *
4 * Author     Alain Greiner (2016,2017,2018)
5 *
6 * Copyright (c)  UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-kernel.
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 <errno.h>
28#include <vfs.h>
29#include <process.h>
30#include <thread.h>
31#include <printk.h>
32
33#include <syscalls.h>
34
35//////////////////////////////////
36int sys_unlink ( char * pathname )
37{
38    error_t   error;
39    xptr_t    root_inode_xp;           // extended pointer on path root inode
40
41    char      kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
42
43    thread_t     * this     = CURRENT_THREAD;
44    process_t    * process  = this->process;
45
46#if (DEBUG_SYS_UNLINK || CONFIG_INSTRUMENTATION_SYSCALLS)
47uint64_t     tm_start = hal_get_cycles();
48#endif
49
50    // check pathname length
51    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
52    {
53
54#if DEBUG_SYSCALLS_ERROR
55printk("\n[ERROR] in %s : pathname too long\n", __FUNCTION__ );
56#endif
57        this->errno = ENFILE;
58        return -1;
59    }
60
61    // copy pathname in kernel space
62    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
63
64#if DEBUG_SYS_UNLINK
65if( DEBUG_SYS_UNLINK < tm_start )
66printk("\n[%s] thread[%x,%x] enter for <%s> / cycle %d\n",
67__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_start );
68#endif
69 
70    // compute root inode for path
71    if( kbuf[0] == '/' )                        // absolute path
72    {
73        // use extended pointer on VFS root inode
74        root_inode_xp = process->vfs_root_xp;
75    }
76    else                                        // relative path
77    {
78        // get cluster and local pointer on reference process
79        xptr_t      ref_xp  = process->ref_xp;
80        process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
81        cxy_t       ref_cxy = GET_CXY( ref_xp );
82
83        // use extended pointer on CWD inode
84        root_inode_xp = hal_remote_l64( XPTR( ref_cxy , &ref_ptr->cwd_xp ) );
85    }
86
87    // call the relevant VFS function
88    error  = vfs_unlink( root_inode_xp , kbuf );
89
90    if( error )
91    {
92
93#if DEBUG_SYSCALLS_ERROR
94printk("\n[ERROR] in %s : cannot unlink file/dir %s\n", __FUNCTION__, kbuf );
95#endif
96        this->errno = ENFILE;
97        return -1;
98    }
99
100#if (DEBUG_SYS_UNLINK || CONFIG_INSTRUMENTATION_SYSCALLS)
101uint64_t     tm_end = hal_get_cycles();
102#endif
103
104#if DEBUG_SYS_UNLINK
105if( DEBUG_SYS_UNLINK < tm_end )
106printk("\n[%s] thread[%x,%x] exit for <%s> / cycle %d\n",
107__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_end );
108#endif
109 
110#if CONFIG_INSTRUMENTATION_SYSCALLS
111hal_atomic_add( &syscalls_cumul_cost[SYS_UNLINK] , tm_end - tm_start );
112hal_atomic_add( &syscalls_occurences[SYS_UNLINK] , 1 );
113#endif
114
115    return 0;
116
117} // end sys_unlink()
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