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57 lines
1,014 B
Groff
57 lines
1,014 B
Groff
.TH SENDFD 3
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.SH NAME
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sendfd, recvfd \- pass file descriptors along Unix domain sockets
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.SH SYNOPSIS
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.B
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#include <u.h>
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.PP
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.B
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#include <libc.h>
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.PP
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.B
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int sendfd(int socket, int fd)
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.PP
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.B
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int recvfd(int socket)
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.SH DESCRIPTION
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.I Recvfd
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and
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.I sendfd
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can be used to pass an open file descriptor over
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a Unix domain socket from one process to another.
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Since
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.MR pipe (3)
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is implemented with
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.MR socketpair (2)
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instead of
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.MR pipe (2) ,
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.I socket
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can be a file descriptor obtained from
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.MR pipe (3) .
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.PP
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.I Sendfd
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sends the file descriptor
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.I fd
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along the socket to a process calling
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.I recvfd
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on the other end.
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.PP
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It is assumed that the two sides have coordinated
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and agreed to transfer a file descriptor already, so
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that the
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.I sendfd
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is met with a
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.I recvfd
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instead of an ordinary
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.IR read .
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.PP
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The file descriptor number may change on its way
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between processes, but the kernel structure it represents
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will not.
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.SH SOURCE
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.B \*9/src/lib9/sendfd.c
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.SH SEE ALSO
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.MR socketpair (2) ,
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.I sendmsg
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in
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.MR send (2)
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