| 1 | /* |
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| 2 | * kern/sys_lseek.c - set the read/write offset of an opened file |
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| 3 | * |
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| 4 | * Copyright (c) 2008,2009,2010,2011,2012 Ghassan Almaless |
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| 5 | * Copyright (c) 2011,2012 UPMC Sorbonne Universites |
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| 6 | * |
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| 7 | * This file is part of ALMOS-kernel. |
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| 8 | * |
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| 9 | * ALMOS-kernel is free software; you can redistribute it and/or modify it |
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| 10 | * under the terms of the GNU General Public License as published by |
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| 11 | * the Free Software Foundation; version 2.0 of the License. |
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| 12 | * |
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| 13 | * ALMOS-kernel is distributed in the hope that it will be useful, but |
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| 14 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 16 | * General Public License for more details. |
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| 17 | * |
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| 18 | * You should have received a copy of the GNU General Public License |
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| 19 | * along with ALMOS-kernel; if not, write to the Free Software Foundation, |
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| 20 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 21 | */ |
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| 22 | |
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| 23 | #include <kernel_config.h> |
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| 24 | #include <hal_types.h> |
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| 25 | #include <hal_uspace.h> |
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| 26 | #include <errno.h> |
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| 27 | #include <vfs.h> |
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| 28 | #include <vmm.h> |
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| 29 | #include <thread.h> |
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| 30 | #include <printk.h> |
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| 31 | #include <process.h> |
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| 32 | |
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| 33 | //////////////////////////////// |
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| 34 | int sys_lseek (uint32_t file_id, |
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| 35 | uint32_t offset, |
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| 36 | uint32_t whence ) |
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| 37 | { |
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| 38 | error_t error; |
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| 39 | xptr_t file_xp; |
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| 40 | uint32_t new_offset; |
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| 41 | |
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| 42 | thread_t * this = CURRENT_THREAD; |
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| 43 | process_t * process = this->process; |
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| 44 | |
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| 45 | // check file_id argument |
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| 46 | if( file_id >= CONFIG_PROCESS_FILE_MAX_NR ) |
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| 47 | { |
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| 48 | printk("\n[ERROR] in %s : illegal file descriptor index = %d\n", |
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| 49 | __FUNCTION__ , file_id ); |
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| 50 | this->errno = EBADFD; |
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| 51 | return -1; |
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| 52 | } |
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| 53 | |
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| 54 | // get extended pointer on remote file descriptor |
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| 55 | file_xp = process_fd_get_xptr( process , file_id ); |
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| 56 | |
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| 57 | if( file_xp == XPTR_NULL ) |
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| 58 | { |
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| 59 | printk("\n[ERROR] in %s : undefined file descriptor index = %d\n", |
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| 60 | __FUNCTION__ , file_id ); |
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| 61 | this->errno = EBADFD; |
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| 62 | return -1; |
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| 63 | } |
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| 64 | |
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| 65 | /* FIXME: file may be closed in parallel |
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| 66 | * of seek/read/write/mmap ..etc |
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| 67 | * so file may be NULL or invalid */ |
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| 68 | |
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| 69 | // call relevant VFS function |
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| 70 | error = vfs_lseek( file_xp , offset , whence , &new_offset ); |
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| 71 | |
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| 72 | if( error ) |
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| 73 | { |
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| 74 | printk("\n[ERROR] in %s : cannot seek file = %d\n", |
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| 75 | __FUNCTION__ , file_id ); |
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| 76 | this->errno = error; |
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| 77 | return -1; |
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| 78 | } |
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| 79 | |
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| 80 | return new_offset; |
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| 81 | } |
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