source: trunk/kernel/syscalls/sys_unlink.c @ 604

Last change on this file since 604 was 604, checked in by alain, 4 years ago

Improve the FAT32 file system to support cat, rm, cp commands.

File size: 3.2 KB
Line 
1/*
2 * sys_unlink.c - file unlink a file
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    char      kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
40
41    thread_t     * this     = CURRENT_THREAD;
42    process_t    * process  = this->process;
43
44#if (DEBUG_SYS_UNLINK || CONFIG_INSTRUMENTATION_SYSCALLS)
45uint64_t     tm_start = hal_get_cycles();
46#endif
47
48    // check pathname length
49    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
50    {
51
52#if DEBUG_SYSCALLS_ERROR
53printk("\n[ERROR] in %s : pathname too long\n", __FUNCTION__ );
54#endif
55        this->errno = ENFILE;
56        return -1;
57    }
58
59    // copy pathname in kernel space
60    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
61
62#if DEBUG_SYS_UNLINK
63if( DEBUG_SYS_UNLINK < tm_start )
64printk("\n[%s] thread[%x,%x] enter for <%s> / cycle %d\n",
65__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_start );
66#endif
67 
68    // get cluster and local pointer on reference process
69    xptr_t      ref_xp  = process->ref_xp;
70    process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
71    cxy_t       ref_cxy = GET_CXY( ref_xp );
72
73    // get the cwd lock in write mode from reference process
74    remote_rwlock_wr_acquire( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
75
76    // get extended pointer on cwd inode
77    xptr_t cwd_xp = hal_remote_l64( XPTR( ref_cxy , &ref_ptr->vfs_cwd_xp ) );
78
79    // call relevant VFS function
80    error  = vfs_unlink( cwd_xp , kbuf );
81
82    // release the cwd lock in reference process
83    remote_rwlock_wr_release( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
84
85    if( error )
86    {
87
88#if DEBUG_SYSCALLS_ERROR
89printk("\n[ERROR] in %s : cannot unlink file/dir %s\n", __FUNCTION__, kbuf );
90#endif
91        this->errno = ENFILE;
92        return -1;
93    }
94
95#if (DEBUG_SYS_UNLINK || CONFIG_INSTRUMENTATION_SYSCALLS)
96uint64_t     tm_end = hal_get_cycles();
97#endif
98
99#if DEBUG_SYS_UNLINK
100if( DEBUG_SYS_UNLINK < tm_end )
101printk("\n[%s] thread[%x,%x] exit for <%s> / cycle %d\n",
102__FUNCTION__, process->pid, this->trdid, kbuf, (uint32_t)tm_end );
103#endif
104 
105#if CONFIG_INSTRUMENTATION_SYSCALLS
106hal_atomic_add( &syscalls_cumul_cost[SYS_UNLINK] , tm_end - tm_start );
107hal_atomic_add( &syscalls_occurences[SYS_UNLINK] , 1 );
108#endif
109
110    return 0;
111
112} // end sys_unlink()
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