472ced39ef
close_range(min, max, flags) allows for a range of descriptors to be closed. The Python folk have indicated that they would much prefer this interface to closefrom(2), as the case may be that they/someone have special fds dup'd to higher in the range and they can't necessarily closefrom(min) because they don't want to hit the upper range, but relocating them to lower isn't necessarily feasible. sys_closefrom has been rewritten to use kern_close_range() using ~0U to indicate closing to the end of the range. This was chosen rather than requiring callers of kern_close_range() to hold FILEDESC_SLOCK across the call to kern_close_range for simplicity. The flags argument of close_range(2) is currently unused, so any flags set is currently EINVAL. It was added to the interface in Linux so that future flags could be added for, e.g., "halt on first error" and things of this nature. This patch is based on a syscall of the same design that is expected to be merged into Linux. Reviewed by: kib, markj, vangyzen (all slightly earlier revisions) Differential Revision: https://reviews.freebsd.org/D21627
91 lines
2.6 KiB
Groff
91 lines
2.6 KiB
Groff
.\" Copyright (c) 2009 Hudson River Trading LLC
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.\" Written by: John H. Baldwin <jhb@FreeBSD.org>
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.\" 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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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.\" $FreeBSD$
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.\"
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.Dd April 12, 2020
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.Dt CLOSEFROM 2
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.Os
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.Sh NAME
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.Nm closefrom ,
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.Nm close_range
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.Nd delete open file descriptors
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft void
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.Fn closefrom "int lowfd"
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.Ft int
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.Fn close_range "u_int lowfd" "u_int highfd" "int flags"
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.Sh DESCRIPTION
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The
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.Fn closefrom
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system call deletes all open file descriptors greater than or equal to
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.Fa lowfd
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from the per-process object reference table.
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Any errors encountered while closing file descriptors are ignored.
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.Pp
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The
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.Fn close_range
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system call deletes all open file descriptors between
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.Fa lowfd
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and
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.Fa highfd
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inclusive, clamped to the range of open file descriptors.
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Any errors encountered while closing file descriptors are ignored.
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There are currently no defined
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.Fa flags .
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.Sh RETURN VALUES
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Upon successful completion,
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.Fn close_range
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returns a value
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of 0.
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Otherwise, a value of -1 is returned and the global variable
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The
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.Fn close_range
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system call
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The
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.Fa highfd
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argument is lower than the
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.Fa lowfd
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argument.
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.It Bq Er EINVAL
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An invalid flag was set.
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.El
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.Sh SEE ALSO
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.Xr close 2
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.Sh HISTORY
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The
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.Fn closefrom
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function first appeared in
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.Fx 8.0 .
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