73 lines
1.6 KiB
Plaintext
73 lines
1.6 KiB
Plaintext
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.TH FVERSION 2
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.SH NAME
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fversion \- initialize 9P connection and negotiate version
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.SH SYNOPSIS
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.nf
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.PP
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.ft L
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#include <u.h>
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#include <libc.h>
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.PP
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.ft P
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.B
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int fversion(int fd, int bufsize, char *version, int nversion)
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.SH DESCRIPTION
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.PP
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.I Fversion
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is used to initialize the 9P connection represented by
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.I fd
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and to negotiate the version of the protocol to be used.
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.PP
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The
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.I bufsize
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determines the size of the I/O buffer used to stage 9P requests to the server,
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subject to the constraints of the server itself.
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The
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.I version
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is a text string that represents the highest version level the protocol will support.
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The
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.I version
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will be overwritten with the negotiated, possibly lower, version of the protocol.
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The return value of
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.I fversion
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is the length of the returned version string; the value of
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.I nversion
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is therefore not the length of the version string presented to the system call,
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but the total length of the buffer to accept the final result, in the manner of a read system call.
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.PP
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Default values of zero for
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.I bufsize
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and the empty string for
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.I version
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will negotiate sensible defaults for the connection.
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If
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.I version
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is the empty string,
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.I nversion
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must still be large enough to receive the returned version string.
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.PP
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The interpretation of the version strings is defined in
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.IR version (5).
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.PP
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It is rare to use
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.IR fversion
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directly; usually the default negotiation performed
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by the kernel during
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.B mount
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(see
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.IR bind (2))
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or even more commonly
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.B amount
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(see
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.IR auth (2))
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is sufficient.
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.SH SOURCE
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.B /sys/src/libc/9syscall
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.SH SEE ALSO
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.IR intro (5),
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.IR version (5),
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.IR fauth (2).
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.SH DIAGNOSTICS
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Sets
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.IR errstr .
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