57 lines
1.3 KiB
Text
57 lines
1.3 KiB
Text
.TH FD2PATH 2
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.SH NAME
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fd2path \- return file name associated with file descriptor
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.PP
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.B
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int fd2path(int fd, char *buf, int nbuf)
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.SH DESCRIPTION
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As described in
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.IR intro (2),
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the kernel stores a rooted path name with every open file or directory;
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typically, it is the name used in the original access of the file.
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.I Fd2path
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returns the path name associated with open file descriptor
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.IR fd .
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Up to
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.I nbuf
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bytes of the name are stored in
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.IR buf ;
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if the name is too long, it will be silently truncated at a UTF-8
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character boundary.
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The name is always null-terminated.
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The return value of
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.I fd2path
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will be zero unless an error occurs.
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.PP
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Changes to the underlying name space do not update the path name
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stored with the file descriptor.
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Therefore,
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the path returned by
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.I fd2path
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may no longer refer to the same file (or indeed any file)
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after some component directory or file in the path has been removed, renamed
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or rebound.
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.PP
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As an example,
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.IR getwd (2)
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is implemented by opening
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.B .
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and executing
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.I fd2path
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on the resulting file descriptor.
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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 bind (1),
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.IR ns (1),
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.IR bind (2),
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.IR intro (2),
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.IR getwd (2),
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.IR proc (3)
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.SH DIAGNOSTICS
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Sets
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.IR errstr .
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