path: root/lib/libcrypto/man/DSA_meth_new.3

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.Dd $Mdocdate: July 10 2022 $
.Dt DSA_METH_NEW 3
.Os
.Sh NAME
.Nm DSA_meth_new ,
.Nm DSA_meth_free ,
.Nm DSA_meth_dup ,
.Nm DSA_meth_get0_name ,
.Nm DSA_meth_set1_name ,
.Nm DSA_meth_set_sign ,
.Nm DSA_meth_set_finish
.Nd build up DSA methods
.Sh SYNOPSIS
.In openssl/dsa.h
.Ft DSA_METHOD *
.Fo DSA_meth_new
.Fa "const char *name"
.Fa "int flags"
.Fc
.Ft void
.Fo DSA_meth_free
.Fa "DSA_METHOD *meth"
.Fc
.Ft DSA_METHOD *
.Fo DSA_meth_dup
.Fa "const DSA_METHOD *meth"
.Fc
.Ft const char *
.Fo DSA_meth_get0_name
.Fa "const DSA_METHOD *meth"
.Fc
.Ft int
.Fo DSA_meth_set1_name
.Fa "DSA_METHOD *meth"
.Fa "const char *name"
.Fc
.Ft int
.Fo DSA_meth_set_sign
.Fa "DSA_METHOD *meth"
.Fa "DSA_SIG *(*sign)(const unsigned char *, int, DSA *)"
.Fc
.Ft int
.Fo DSA_meth_set_finish
.Fa "DSA_METHOD *meth"
.Fa "int (*finish)(DSA *)"
.Fc
.Sh DESCRIPTION
The
.Vt DSA_METHOD
structure holds function pointers for custom DSA implementations.
.Pp
.Fn DSA_meth_new
creates a new
.Vt DSA_METHOD
structure.
A copy of the NUL-terminated
.Fa name
is stored in the new
.Vt DSA_METHOD
object.
Any new
.Vt DSA
object constructed from this
.Vt DSA_METHOD
will have the given
.Fa flags
set by default.
.Pp
.Fn DSA_meth_dup
creates a deep copy of
.Fa meth .
This might be useful for creating a new
.Vt DSA_METHOD
based on an existing one, but with some differences.
.Pp
.Fn DSA_meth_free
destroys
.Fa meth
and frees any memory associated with it.
.Pp
.Fn DSA_meth_get0_name
returns an internal pointer to the name of
.Fa meth .
.Fn DSA_meth_set1_name
stores a copy of the NUL-terminated
.Fa name
in
.Fa meth
after freeing the previously stored name.
Method names are ignored by the default DSA implementation but can be
used by alternative implementations and by the application program.
.Pp
.Fn DSA_meth_set_sign
sets the function used for creating a DSA signature.
This function will be called from
.Xr DSA_do_sign 3
and indirectly from
.Xr DSA_sign 3 .
The parameters of
.Fa sign
have the same meaning as for
.Xr DSA_do_sign 3 .
.Pp
.Fn DSA_meth_set_finish
sets an optional function for destroying a
.Vt DSA
object.
Unless
.Fa finish
is
.Dv NULL ,
it will be called from
.Xr DSA_free 3 .
It takes the same argument
and is intended to do DSA implementation specific cleanup.
The memory used by the
.Vt DSA
object itself should not be freed by the
.Fa finish
function.
.Sh RETURN VALUES
.Fn DSA_meth_new
and
.Fn DSA_meth_dup
return the newly allocated
.Vt DSA_METHOD
object or
.Dv NULL
on failure.
.Pp
.Fn DSA_meth_get0_name
returns an internal pointer which must not be freed by the caller.
.Pp
.Fn DSA_meth_set1_name
and all
.Fn DSA_meth_set_*
functions return 1 on success or 0 on failure.
In the current implementation, only
.Fn DSA_meth_set1_name
can actually fail.
.Sh SEE ALSO
.Xr DSA_do_sign 3 ,
.Xr DSA_new 3 ,
.Xr DSA_set_method 3 ,
.Xr DSA_SIG_new 3 ,
.Xr DSA_sign 3
.Sh HISTORY
These functions first appeared in OpenSSL 1.1.0.
.Pp
.Fn DSA_meth_new ,
.Fn DSA_meth_free ,
.Fn DSA_meth_dup ,
.Fn DSA_meth_set_sign ,
and
.Fn DSA_meth_set_finish
have been available since
.Ox 6.3 .
.Pp
.Fn DSA_meth_get0_name
and
.Fn DSA_meth_set1_name
have been available since
.Ox 7.2 .