.\" $OpenBSD: EVP_CIPHER_do_all.3,v 1.2 2024/01/31 08:02:53 tb Exp $
.\"
.\" Copyright (c) 2023,2024 Theo Buehler <tb@openbsd.org>
.\" Copyright (c) 2021 Ingo Schwarze <schwarze@openbsd.org>
.\"
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.Dd $Mdocdate: January 31 2024 $
.Dt EVP_CIPHER_DO_ALL 3
.Os
.Sh NAME
.Nm EVP_CIPHER_do_all ,
.Nm EVP_CIPHER_do_all_sorted ,
.Nm EVP_MD_do_all ,
.Nm EVP_MD_do_all_sorted
.Nd iterate over lookup tables for ciphers and digests
.Sh SYNOPSIS
.In openssl/evp.h
.Ft void
.Fo EVP_CIPHER_do_all
.Fa "void (*fn)(const EVP_CIPHER *cipher, const char *from,\
 const char *to, void *arg)"
.Fa "void *arg"
.Fc
.Ft void
.Fo EVP_CIPHER_do_all_sorted
.Fa "void (*fn)(const EVP_CIPHER *cipher, const char *from,\
 const char *to, void *arg)"
.Fa "void *arg"
.Fc
.Ft void
.Fo EVP_MD_do_all
.Fa "void (*fn)(const EVP_MD *md, const char *from,\
 const char *to, void *arg)"
.Fa "void *arg"
.Fc
.Ft void
.Fo EVP_MD_do_all_sorted
.Fa "void (*fn)(const EVP_MD *md, const char *from,\
 const char *to, void *arg)"
.Fa "void *arg"
.Fc
.Bd -literal
typedef struct {
        int	    type;
        int	    alias;
        const char *name;
        const char *data;
} OBJ_NAME;
.Ed
.Pp
.Ft void
.Fo OBJ_NAME_do_all
.Fa "int type"
.Fa "void (*fn)(const OBJ_NAME *obj_name, void *arg)"
.Fa "void *arg"
.Fc
.Ft void
.Fo OBJ_NAME_do_all_sorted
.Fa "int type"
.Fa "void (*fn)(const OBJ_NAME *obj_name, void *arg)"
.Fa "void *arg"
.Fc
.Sh DESCRIPTION
.Fn EVP_CIPHER_do_all
calls
.Fa fn
on every entry of the global table of cipher names and aliases.
For a cipher name entry,
.Fa fn
is called with a non-NULL
.Fa cipher ,
its non-NULL cipher name
.Fa from ,
a NULL
.Fa to ,
and the
.Fa arg
pointer.
For an alias entry,
.Fa fn
is called with a NULL
.Fa cipher ,
its alias
.Fa from ,
the cipher name that alias points
.Fa to ,
and the
.Fa arg
pointer.
.Pp
.Fn EVP_CIPHER_do_all_sorted
is similar, except that it processes the cipher names and aliases
in lexicographic order of their
.Fa from
names as determined by
.Xr strcmp 3 .
.Pp
.Fn EVP_MD_do_all
calls
.Fa fn
on every entry of the global table of digest names and aliases.
For a digest name entry,
.Fa fn
is called with a non-NULL
.Fa md ,
its non-NULL digest name
.Fa from ,
a NULL
.Fa to ,
and the
.Fa arg
pointer.
For an alias entry,
.Fa fn
is called with a NULL
.Fa md ,
its alias
.Fa from ,
the digest name that alias points
.Fa to ,
and the
.Fa arg
pointer.
.Pp
.Fn EVP_MD_do_all_sorted
is similar, except that it processes the digest names and aliases
in lexicographic order of their
.Fa from
names as determined by
.Xr strcmp 3 .
.Pp
.Vt OBJ_NAME
is an abstraction of the types underlying the lookup tables
for ciphers and their aliases, and digests and their aliases, respectively.
For a cipher,
.Fa type
is
.Dv OBJ_NAME_TYPE_CIPHER_METH ,
.Fa alias
is 0,
.Fa name
is its lookup name and
.Fa data
is the
.Vt EVP_CIPHER
object it represents, cast to
.Vt const char * .
For a cipher alias,
.Fa type
is
.Dv OBJ_NAME_TYPE_CIPHER_METH ,
.Fa alias
is
.Dv OBJ_NAME_ALIAS ,
.Fa name
is its lookup name and
.Fa data
is the name it aliases.
Digests representing an
.Vt EVP_MD
object and their aliases are represented similarly, except that their type is
.Dv OBJ_NAME_TYPE_MD_METH .
.Pp
.Fn OBJ_NAME_do_all
calls
.Fa fn
on every
.Fa obj_name
in the table that has the given
.Fa type
(either
.Dv OBJ_NAME_TYPE_CIPHER_METH
or
.Dv OBJ_NAME_TYPE_MD_METH ) ,
also passing the
.Fa arg
pointer.
.Fn OBJ_NAME_do_all_sorted
is similar except that it processes the
.Fa obj_name
in lexicographic order of their names as determined by
.Xr strcmp 3 .
.Sh SEE ALSO
.Xr evp 3 ,
.Xr EVP_get_cipherbyname 3 ,
.Xr EVP_get_digestbyname 3
.Sh HISTORY
These functions first appeared in OpenSSL 1.0.0 and have been available since
.Ox 4.9 .
.Sh CAVEATS
.Fn EVP_CIPHER_do_all_sorted ,
.Fn EVP_MD_do_all_sorted ,
and
.Fn OBJ_NAME_do_all_sorted
cannot report errors.
In some implementations they need to allocate internally and
if memory allocation fails they do nothing at all,
without telling the caller about the problem.