Configurations of OpenSSL target platforms
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Target configurations are a collection of facts that we know about
different platforms and their capabilities. We organise them in a
hash table, where each entry represent a specific target.
In each table entry, the following keys are significant:
inherit_from => Other targets to inherit values from.
Explained further below. [1]
template => Set to 1 if this isn't really a platform
target. Instead, this target is a template
upon which other targets can be built.
Explained further below. [1]
sys_id => System identity for systems where that
is difficult to determine automatically.
cc => The compiler command, usually one of "cc",
"gcc" or "clang". This command is normally
also used to link object files and
libraries into the final program.
cflags => Flags that are used at all times when
compiling.
debug_cflags => Extra compilation flags used when making a
debug build (when Configure receives the
--debug option). Typically something like
"-g -O0".
release_cflags => Extra compilation flags used when making a
release build (when Configure receives the
--release option, or doesn't receive the
--debug option). Typically something like
"-O" or "-O3".
thread_cflags => Extra compilation flags used when
compiling with threading enabled.
Explained further below. [2]
shared_cflag => Extra compilation flags used when
compiling for shared libraries, typically
something like "-fPIC".
ld => the linker command, usually not defined
(meaning the compiler command is used
instead).
(NOTE: this is here for future use, it's
not implemented yet)
lflags => the flags that are used at all times when
linking. These can have a % sign in them
showing where the OpenSSL libraries should
appear, otherwise these flags will come
last. So in a typical links situation,
this is a quick table of results:
"-foo%-bar" > -foo -lssl -lcrypto -bar
"-foo%" > -foo -lssl -lcrypto
"-foo" > -lssl -lcrypto -foo
debug_lflags => Like debug_cflags, but used when linking.
release_lflags => Like release_cflags, but used when linking.
shared_lflags => Like shared_cflags, but used when linking.
ar => The library archive command, the default is
"ar".
(NOTE: this is here for future use, it's
not implemented yet)
arflags => Flags to be used with the library archive
command.
ranlib => The library archive indexing command, the
default is 'ranlib' it it exists.
unistd => An alternative header to the typical
'<unistd.h>'. This is very rarely needed.
shared_extension => File name extension used for shared
libraries.
obj_extension => File name extension used for object files.
On unix, this defaults to ".o" (NOTE: this
is here for future use, it's not
implemented yet)
exe_extension => File name extension used for executable
files. On unix, this defaults to "" (NOTE:
this is here for future use, it's not
implemented yet)
dso_scheme => The type of dynamic shared objects to build
for. This mostly comes into play with
engines, but can be used for other purposes
as well. Valid values are "DLFCN"
(dlopen() et al), "DLFCN_NO_H" (for systems
that use dlopen() et al but do not have
fcntl.h), "DL" (shl_load() et al), "WIN32"
and "VMS".
perlasm_scheme => The perlasm method used to created the
assembler files used when compiling with
assembler implementations.
shared_target => The shared library building method used.
This is a target found in Makefile.shared.
build_scheme => The scheme used to build up a Makefile.
In its simplest form, the value is a string
with the name of the build scheme.
The value may also take the form of a list
of strings, if the build_scheme is to have
some options. In this case, the first
string in the list is the name of the build
scheme.
Currently recognised build schemes are
"mk1mf" and "unixmake". Others may appear
in the future.
multilib => On systems that support having multiple
implementations of a library (typically a
32-bit and a 64-bit variant), this is used
to have the different variants in different
directories.
bn_ops => Building options (was just bignum options
in the earlier history of this option,
hence the name). This a string of words
that describe properties on the designated
target platform, such as the type of
integers used to build up the bitnum,
different ways to implement certain ciphers
and so on. To fully comprehend the
meaning, the best is to read the affected
source.
The valid words are:
BN_LLONG use 'unsigned long long' in
some bignum calculations.
This has no value when
SIXTY_FOUR_BIT or
SIXTY_FOUR_BIT_LONG is given.
RC4_CHAR makes the basic RC4 unit of
calculation an unsigned char.
SIXTY_FOUR_BIT processor registers
are 64 bits, long is
32 bits, long long is
64 bits.
SIXTY_FOUR_BIT_LONG processor registers
are 64 bits, long is
64 bits.
THIRTY_TWO_BIT processor registers
are 32 bits.
EXPORT_VAR_AS_FN for shared libraries,
export vars as
accessor functions.
cpuid_obj => assembler implementation of cpuid code as
well as OPENSSL_cleanse().
Default to mem_clr.o
bn_obj => assembler implementation of core bignum
functions.
Defaults to bn_asm.o
ec_obj => assembler implementation of core EC
functions.
des_obj => assembler implementation of core DES
encryption functions.
Defaults to 'des_enc.o fcrypt_b.o'
aes_obj => assembler implementation of core AES
functions.
Defaults to 'aes_core.o aes_cbc.o'
bf_obj => assembler implementation of core BF
functions.
Defaults to 'bf_enc.o'
md5_obj => assembler implementation of core MD5
functions.
sha1_obj => assembler implementation of core SHA1,
functions, and also possibly SHA256 and
SHA512 ones.
cast_obj => assembler implementation of core BF
functions.
Defaults to 'c_enc.o'
rc4_obj => assembler implementation of core BF
functions.
Defaults to 'rc4_enc.o rc4_skey.o'
rmd160_obj => assembler implementation of core RMD160
functions.
rc5_obj => assembler implementation of core RC4
functions.
Defaults to 'rc5_enc.o'
wp_obj => assembler implementation of core WHIRLPOOL
functions.
cmll_obj => assembler implementation of core CAMELLIA
functions.
Defaults to 'camellia.o cmll_misc.o cmll_cbc.o'
modes_obj => assembler implementation of the
functions gcm_gmult_4bit and gcm_ghash_4bit.
padlock_obj => assembler implementation of core parts of
the padlock engine. This is mandatory on
any platform where the padlock engine might
actually be built.
[1] as part of the target configuration, one can have a key called
'inherit_from' that indicate what other configurations to inherit
data from. These are resolved recursively.
Inheritance works as a set of default values that can be overriden
by corresponding key values in the inheriting configuration.
Note 1: any configuration table can be used as a template.
Note 2: pure templates have the attribute 'template => 1' and
cannot be used as build targets.
If several configurations are given in the 'inherit_from' array,
the values of same attribute are concatenated with space
separation. With this, it's possible to have several smaller
templates for different configuration aspects that can be combined
into a complete configuration.
instead of a scalar value or an array, a value can be a code block
of the form 'sub { /* your code here */ }'. This code block will
be called with the list of inherited values for that key as
arguments. In fact, the concatenation of strings is really done
by using 'sub { join(" ",@_) }' on the list of inherited values.
An example:
"foo" => {
template => 1,
haha => "ha ha",
hoho => "ho",
ignored => "This should not appear in the end result",
},
"bar" => {
template => 1,
haha => "ah",
hoho => "haho",
hehe => "hehe"
},
"laughter" => {
inherit_from => [ "foo", "bar" ],
hehe => sub { join(" ",(@_,"!!!")) },
ignored => "",
}
The entry for "laughter" will become as follows after processing:
"laughter" => {
haha => "ha ha ah",
hoho => "ho haho",
hehe => "hehe !!!",
ignored => ""
}
[2] OpenSSL is built with threading capabilities unless the user
specifies 'no-threads'. The value of the key 'thread_cflags' may
be "(unknown)", in which case the user MUST give some compilation
flags to Configure.
Historically, the target configurations came in form of a string with
values separated by colons. This use is deprecated. The string form
looked like this:
"target" => "{cc}:{cflags}:{unistd}:{thread_cflag}:{sys_id}:{lflags}:{bn_ops}:{cpuid_obj}:{bn_obj}:{ec_obj}:{des_obj}:{aes_obj}:{bf_obj}:{md5_obj}:{sha1_obj}:{cast_obj}:{rc4_obj}:{rmd160_obj}:{rc5_obj}:{wp_obj}:{cmll_obj}:{modes_obj}:{padlock_obj}:{perlasm_scheme}:{dso_scheme}:{shared_target}:{shared_cflag}:{shared_ldflag}:{shared_extension}:{ranlib}:{arflags}:{multilib}"
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