2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
100 lines
3.8 KiB
Groff
100 lines
3.8 KiB
Groff
.\" $NetBSD: syscall.2,v 1.18 2009/08/07 19:34:46 dsl Exp $
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.\"
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.\" Copyright (c) 1980, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)syscall.2 8.1 (Berkeley) 6/16/93
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.\"
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.Dd August 7, 2009
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.Dt SYSCALL 2
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.Os
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.Sh NAME
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.Nm syscall ,
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.Nm __syscall
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.Nd indirect system call
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/syscall.h
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.In unistd.h
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.Ft int
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.Fn syscall "int number" "..."
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.Ft quad_t
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.Fn __syscall "quad_t number" "..."
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.Sh DESCRIPTION
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.Fn syscall
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performs the system call whose assembly language
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interface has the specified
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.Fa number
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with the specified arguments.
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Symbolic constants for system calls can be found in the header file
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.Ao Pa sys/syscall.h Ac .
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The
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.Nm __syscall
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form should be used when one or more of the parameters is a
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64-bit argument to ensure that argument alignment is correct.
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.Pp
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This system call is useful for testing new system calls that
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do not have entries in the C library.
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It should not be used in normal applications.
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.Sh RETURN VALUES
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The return values are defined by the system call being invoked.
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In general, a 0 return value indicates success.
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A \-1 return value indicates an error,
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and an error code is stored in
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.Va errno .
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.Sh HISTORY
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The
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.Fn syscall
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function call appeared in
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.Bx 4.0 .
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.Sh BUGS
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There is no way to simulate system calls that have multiple return values
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such as
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.Xr pipe 2 .
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.Pp
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Since architectures return 32 bit and 64 bit results in different registers,
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it may be impossible to portably convert the result of
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.Fn __syscall
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to a 32bit value.
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For instance sparc returns 32 bit values in %o0 and 64 bit values in %o0:%o1
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(with %o0 containing the most significant part) so a 32 bit right shift
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of the result is needed to get a correct 32 bit result.
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.Pp
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Many architectures mask off the unwanted high bits of the syscall number,
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rather than returning an error.
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.Pp
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Due to ABI implementation differences in passing struct or union
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type arguments to system calls between different processors, all
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system calls pass instead pointers to such structs or unions, even
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when the documentation of the system call mentions otherwise.
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The conversion between passing structs and unions is handled normally
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via userland stubs.
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The correct arguments for the kernel entry
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points for each system call can be found in the header file
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.Ao Pa sys/syscallargs.h Ac
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