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>register_sysctl_table</SPAN
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><H2
>Name</H2
>register_sysctl_table -- register a sysctl hierarchy
</DIV
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><H2
>Synopsis</H2
><DIV
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><P
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><P
><CODE
><CODE
CLASS="FUNCDEF"
>struct ctl_table_header * <TT
CLASS="FUNCTION"
>register_sysctl_table </TT
></CODE
>(ctl_table * <TT
CLASS="PARAMETER"
><I
>table</I
></TT
>, int <TT
CLASS="PARAMETER"
><I
>insert_at_head</I
></TT
>);</CODE
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><H2
>Arguments</H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="PARAMETER"
><I
>table</I
></TT
></DT
><DD
><P
> the top-level table structure
</P
></DD
><DT
><TT
CLASS="PARAMETER"
><I
>insert_at_head</I
></TT
></DT
><DD
><P
> whether the entry should be inserted in front or at the end
</P
></DD
></DL
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><A
NAME="AEN2758"
></A
><H2
>Description</H2
><P
> Register a sysctl table hierarchy. <TT
CLASS="PARAMETER"
><I
>table</I
></TT
> should be a filled in ctl_table
array. An entry with a ctl_name of 0 terminates the table.
</P
><P
> The members of the &ctl_table structure are used as follows:
</P
><P
> ctl_name - This is the numeric sysctl value used by sysctl(2). The number
must be unique within that level of sysctl
</P
><P
> procname - the name of the sysctl file under /proc/sys. Set to <TT
CLASS="CONSTANT"
>NULL</TT
> to not
enter a sysctl file
</P
><P
> data - a pointer to data for use by proc_handler
</P
><P
> maxlen - the maximum size in bytes of the data
</P
><P
> mode - the file permissions for the /proc/sys file, and for sysctl(2)
</P
><P
> child - a pointer to the child sysctl table if this entry is a directory, or
<TT
CLASS="CONSTANT"
>NULL</TT
>.
</P
><P
> proc_handler - the text handler routine (described below)
</P
><P
> strategy - the strategy routine (described below)
</P
><P
> de - for internal use by the sysctl routines
</P
><P
> extra1, extra2 - extra pointers usable by the proc handler routines
</P
><P
> Leaf nodes in the sysctl tree will be represented by a single file
under /proc; non-leaf nodes will be represented by directories.
</P
><P
> sysctl(2) can automatically manage read and write requests through
the sysctl table. The data and maxlen fields of the ctl_table
struct enable minimal validation of the values being written to be
performed, and the mode field allows minimal authentication.
</P
><P
> More sophisticated management can be enabled by the provision of a
strategy routine with the table entry. This will be called before
any automatic read or write of the data is performed.
</P
><P
> The strategy routine may return
</P
><P
> < 0 - Error occurred (error is passed to user process)
</P
><P
> 0 - OK - proceed with automatic read or write.
</P
><P
> > 0 - OK - read or write has been done by the strategy routine, so
return immediately.
</P
><P
> There must be a proc_handler routine for any terminal nodes
mirrored under /proc/sys (non-terminals are handled by a built-in
directory handler). Several default handlers are available to
cover common cases -
</P
><P
> <TT
CLASS="FUNCTION"
>proc_dostring</TT
>, <TT
CLASS="FUNCTION"
>proc_dointvec</TT
>, <TT
CLASS="FUNCTION"
>proc_dointvec_jiffies</TT
>,
<TT
CLASS="FUNCTION"
>proc_dointvec_minmax</TT
>, <TT
CLASS="FUNCTION"
>proc_doulongvec_ms_jiffies_minmax</TT
>,
<TT
CLASS="FUNCTION"
>proc_doulongvec_minmax</TT
>
</P
><P
> It is the handler's job to read the input buffer from user memory
and process it. The handler should return 0 on success.
</P
><P
> This routine returns <TT
CLASS="CONSTANT"
>NULL</TT
> on a failure to register, and a pointer
to the table header on success.
</P
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