61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/* -*-comment-start: "//";comment-end:""-*-
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* GNU Mes --- Maxwell Equations of Software
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* Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
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*
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* This file is part of GNU Mes.
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*
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* GNU Mes is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* GNU Mes is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <gnu/syscall.h>
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struct mach_msg_int_pointer
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{
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mach_msg_header_t header;
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mach_msg_type_t type_one; int one;
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mach_msg_type_long_t type_two; union {char *two; char pointer[2048];};
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};
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kern_return_t
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__io_read (io_t io, data_t *data, mach_msg_type_number_t *read, loff_t offset, vm_size_t size)
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{
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union message
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{
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struct mach_msg_loff_int request;
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struct mach_msg_int_pointer reply;
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};
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union message message = {0};
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message.request.header.msgh_size = sizeof (message.request);
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message.request.type_one = mach_msg_type_int64;
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message.request.one = offset;
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message.request.type_two = mach_msg_type_int32;
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message.request.two = size;
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kern_return_t result = __syscall_put (io, SYS__io_read,
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&message.request.header,
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sizeof (message.reply));
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if (result == KERN_SUCCESS)
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{
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*read = message.reply.type_two.msgtl_number;
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*data = message.reply.pointer;
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}
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else
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{
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*read = 0;
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*data = 0;
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}
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return result;
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}
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