Finally. We're almost at parity for the template compiler.
Now we have a build option to use templating:
`./configure --enable-asn1-templating`
Tests fail if you build `rfc2459.asn1` with `--template`.
TBD: Figure out what differences remain between the two compilers, and
fix the templating compiler accordingly, adding tests along the
way.
Making IMPLICIT tags work in the templating compiler turned out to be a
simple fix: don't attempt to do anything clever about IMPLICIT tags in
the template generator in the compiler other than denoting them --
instead leave all the smarts about IMPLICIT tags to the interpreter.
This might be a very slight pessimization, but also a great
simplification.
The result is very elegant: when the interpreter finds an IMPLICIT
tag it then recurses to find the template for the body of the type
so-tagged, and evaluates that. Much more elegant than the code
generated by the non-template compiler, not least for not needing
any additional temporary memory allocation.
With this we finally have parity in basic testing of the template
compiler. Indeed, for IMPLICIT tags the template compiler and
interpreter might even be better because they support IMPLICIT tags
with BER lengths, whereas the non-template compiler doesn't (mostly
because `der_replace_tag()` needs to be changed to support it.
And, of course, the template compiler is simply superior in that it
produces smaller code and is *much* easier to work with because the
functions to interpret templates are small and simple. Which means we
can add more functions to deal with other encoding rules fairly
trivially. It should be possible to add all of these with very little
work, almost all of it localized to `lib/asn1/template.c`:
- PER Packed Encoding Rules [X.691]
- XER XML Encoding Rules [X.693]
- OER Octet Encoding Rules [X.696] (intended to replace PER)
- JER JSON Encoding Rules [X.697] (doubles as visual representation)
- GSER Generic String E.R.s [RFC3641] (a visual representation)
- XDR External Data Repr. [STD67][RFC4506]
(XDR is *not* an ASN.1 encoding rules specification, but it's a
*lot* like PER/OER but with 4-octet alignment, and is specified
for the syntax equivalent (XDR) of only a subset of ASN.1 syntax
and semantics.)
All we'd have to do is add variants of `_asn1_{length,encode,decode}()`
for each set of rules, then generate per-type stub functions that call
them (as we already do for DER).
We could then have an encoding rule transliteration program that takes a
`TypeName` and some representation of a value encoded by some encoding
rules, and outputs the same thing encoded by a different set of rules.
This would double as a pretty-printer and parser if we do add support
for JER and/or GSER. It would find the template for the given type
using `dlsym()` against some shared object (possibly `libasn1` itself).
Whereas generating source code for C (or whatever language) for
additional ERs requires much more work. Plus, templates are much
smaller, and the interpreter is tiny, which yields much smaller text and
much smaller CPU icache/dcache footprint, which yields better
performance in many cases.
As well, the template system should be much easier to port to other
languages. Though in the cases of, e.g., Rust, it would require use of
`unsafe` in the interpreter, so in fact the inverse might be true: that
it's easier to generate safe Rust code than to implement a template
interpreter in Rust. Similarly for Haskell, OCAML, etc. But wherever
the template interpreter is easy to implement, it's a huge win.
Note that implementing OER and PER using the templates as they are
currently would be a bit of a challenge, as the interpreter would have
to first do a pass of each SEQUENCE/SET to determine the size and
layout of the OER/PER sequence/set preamble by counting the number of
OPTIONAL/DEFAULT members, BOOLEAN members, and extensibility markers
with extensions present. We could always generate more entries to
encode precomputed preamble metadata. We would also need to add a
template entry type for extensibility markers, which currently we do
not.
Using non-reentrant getpwuid() (or getpwnam(), or getspnam()) can be
dangerous. We had a report of a login application / PAM that calls
those, and Heimdal, by calling them too, clobbered the cached struct
passwd used by the login app / PAM.
it turns out that we don't need to tell lex we don't plan to use unput;
we can just.... not use unput. however, if we're flex, use the command
line option if it's available, to avoid warnings
depending what's available when you compile for iOS it's possible to
be __APPLE__ and not have CF; actually test for it instead of blythely
assuming it can be used
For krb5.conf include/includedir we want to reject non-absolute paths,
but then we need to make sure that we use absolute paths in the tests,
otherwise they fail. Of course ./configure has been defaulting to
relative paths for $srcdir and $objdir. This commit canonicalizes
$srcdir; eventually, no doubt, we'll have to canonicalize $objdir too.
The prior patch removed the definition of the XUA check but failed
to remove the execution of the check. Do so now.
Change-Id: I648a374370d3549db0d98b90f810bd018dc28962
The pop3, telnet and rsh/rcp support was removed from the tree in
e55b0d0ca5. Delete the corresponding
Makefiles so autoconf doesn't try to look for them.
Normally one would dlopen() a shared object's basename, not its absolute
path. However, lib/krb5/plugin.c, in an effort to be zero-conf-ish,
wants to readdir() to find plugins to load, and in the process it ends
up defeating the RTLD's search-the-caller's-rpath.
This commit partially addresses this by allowing the use of $ORIGIN in
plugin_dir values and using them for the default (except on OS X).
This allows multiple Heimdal versions installed on the same host, but
with different plugin ABIs, to co-exist. A step forward for doing make
check on hosts where Heimdal is installed.
For now we hardcode $ORIGIN/../lib/plugin/krb5 (linux, Solaris, *BSD),
or $ORIGIN (Windows; for assemblies objects need to be in the same
directory) and we eval $ORIGIN by using dladdr() (Linux, Solaris) or
GetModuleHandleEx() (Win32, via a dladdr() wrapper in libroken) to find
the path to libkrb5 whose dirname to use as $ORIGIN. For Windows,
because we need the plugins to be in the same directory as libkrb5, we
require a prefix on plugin DLLs ("plugin_krb5_") to distinguish them
from other objects.
We should add a special token to mean "look in $ORIGIN, sure, but
dlopen() the plugin basenames only (so the RTLD can search the rpath)".
__sync_add_and_fetch is treated as a built in function by the compiler if the return value is not used (as in the autoconf test), but it is treated as a regular function when the return value is used
Signed-off-by: Love Hornquist Astrand <lha@h5l.org>
