While YAJL mostly works fine, it did not see any active development in
the last 3 years. OTOH, Jansson is another JSON C implementation, with
a very liberal license, and a much nicer API.
Hence, switch all of libguestfs from YAJL to Jansson:
- configure checks, and buildsystem in general
- packages pulled in the appliance
- actual implementations
- contrib scripts
- documentation
This also makes use of the better APIs available (e.g. json_object_get,
json_array_foreach, and json_object_foreach). This does not change the
API of our OCaml Yajl module.
Do a configure check for the OPEN_UNSAFE flag in the OCaml binding of
Hivex, using it only when available. This makes it possible to use
hivex < 1.3.14 to build libguestfs (the daemon, actually).
Amend the building documentation accordingly, bringing the minimum
version of hivex back as it was before
commit 64f49df747.
common/mlutils: Unix_utils.StatVFS.statvfs: This commit implements a
full-featured binding for the statvfs(3) function.
We then use this to reimplement the daemon statvfs API in OCaml.
Note that the Gnulib fallback is dropped in this commit. It
previously referenced non-existent field names in the fs_usage struct
so it didn't work. Also it's not necessary as POSIX has supported
statvfs(3) since 2001, it's supported in *BSD, macOS > 10.4, and there
is already a Windows fallback.
This directory which previously contained random modules and functions
now has an official purpose: to be the place for any OCaml utility
needed by the OCaml virt tools.
This is just code movement, I didn't (yet) rename or move any of the
modules.
Add a --with-distro=ID argument for configure, so it is possible to
manually specify the distro to use for the packages (in case os-release
does not provide ID=.., or the ID is not recognized yet).
In the case when --with-distro is not set, keep doing the autodetection,
but using os-release only, i.e. dropping the checks for all the other
-release files -- since there is --with-distro, older distros with no
os-release can still be used.
RWMJ: Add documentation to guestfs-building(1).
Move the last remaining function ‘guestfs_int_download_to_tmp’ to
lib/inspect-icon.c (the main, but not only user of this function).
Then remove lib/inspect.c entirely.
This is not quite code motion because I updated the comment for the
function to reflect what it does in reality.
hivex has a function hivex_value_string. We were not calling it under
the mistaken belief that because hivex implements this using iconv,
the function wouldn't work inside the daemon. Instead we
reimplemented the functionality in the library.
This commit deprecates hivex_value_utf8 and removes the library side
code. It replaces it with a plain wrapper around hivex_value_string.
Thanks: Pino Toscano
This commit bundles the ocaml-augeas library (upstream here:
http://git.annexia.org/?p=ocaml-augeas.git;a=summary). It's identical
to the upstream version and should remain so.
We can work towards using system ocaml-augeas, when it's more widely
available.
The following functions were previously reimplemented in OCaml. This
commit replaces them with calls to the C functions:
- is_root_device
- prog_exists
- udev_settle
plus the internal get_verbose_flag function.
However note that we cannot do this for every utility function. In
particular the C function must not call any reply* functions.
This also reimplements the lv_canonical function in OCaml. We cannot
call the original C function because it calls reply_with_perror which
would break the OCaml bindings.
Move the list_filesystems API into the daemon, reimplementing it in
OCaml. Since this API makes many other API calls, it runs a lot
faster in the daemon.
The previously library-side ‘file_architecture’ API is reimplemented
in the daemon, in OCaml.
There are some significant differences compared to the C
implementation:
- The C code used libmagic. That is replaced by calling the ‘file’
command (because that is simpler than using the library).
- The C code had extra cases to deal with compressed files. This is
not necessary since the ‘file’ command supports the ‘-z’ option
which transparently looks inside compressed content (this is a
consequence of the change above).
This commit demonstrates a number of techniques which will be useful
for moving inspection code to the daemon:
- Moving an API from the C library to the OCaml daemon.
- Calling from one OCaml API inside the daemon to another (from
‘Filearch.file_architecture’ to ‘File.file’). This can be done and
is done with C daemon APIs but correct reply_with_error handling is
more difficult in C.
- Use of Str for regular expression matching within the appliance.
This change allows parts of the daemon to be written in the OCaml
programming language. I am using the ‘Main Program in C’ method along
with ‘-output-obj’ to create an object file from the OCaml code /
runtime, as described here:
https://caml.inria.fr/pub/docs/manual-ocaml/intfc.html
Furthermore, change the generator to allow individual APIs to be
implemented in OCaml. This is picked by setting:
impl = OCaml <ocaml_function>;
The generator creates ‘do_function’ (the same one you would have to
write by hand in C), with the function calling the named
‘ocaml_function’ and dealing with marshalling/unmarshalling the OCaml
parameters.
Previously the OCaml compiler was only required if building from git
but was at least theoretically optional if building from tarballs
(although this was never tested). Since we want to write parts of the
daemon in OCaml, this makes OCaml required for all builds.
Note that the ‘--disable-ocaml’ option remains, but it now only
disables OCaml bindings and OCaml virt tools. Using this option does
not disable the OCaml compiler requirement.
Also note that ‘HAVE_OCAML’ changes meaning slightly, so it now means
"build OCaml bindings and tools" (analogous to ‘HAVE_PERL’ and
others). The generator, daemon [in a future commit], and some utility
libraries needed by the generator or daemon do not test for this macro
because we can assume OCaml compiler availability.
After the previous refactoring, we are able to link the daemon to
common/utils, and also remove some of the "duplicate" functions that
the daemon carried ("duplicate" in quotes because they were often not
exact duplicates).
Also this removes the duplicate reimplementation of (most) cleanup
functions in the daemon, since those are provided by libutils now.
It also allows us in future (but not in this commit) to move utility
functions from the daemon into libutils.
Create a module ‘C_utils’ containing functions like ‘drive_name’ and
‘shell_unquote’ which come from the C utilities.
The new directory ‘common/mlutils’ also contains the ‘Unix_utils’
wrappers around POSIX functions missing from the OCaml stdlib.
This refactoring change just moves the cleanup functions around in the
common/utils directory.
libxml2 cleanups are moved to a separate object file, so that we can
still link to libutils even if the main program is not using libxml2
anywhere. Similarly gnulib cleanups.
cleanup.c is renamed to cleanups.c.
A new header file cleanups.h is introduced which will replace
guestfs-internal-frontend-cleanups.h (fully replaced in a later commit).
The new module ‘Std_utils’ contains only functions which are pure
OCaml and depend only on the OCaml stdlib. Therefore these functions
may be used by the generator.
The new module is moved to ‘common/mlstdutils’.
This also removes the "<stdlib>" hack, and the code which copied the
library around.
Also ‘Guestfs_config’, ‘Libdir’ and ‘StringMap’ modules are moved
since these are essentially the same.
The bulk of this change is just updating files which use
‘open Common_utils’ to add ‘open Std_utils’ where necessary.
The ‘Xml’ module is a self-contained library of bindings for libxml2,
with no other dependencies.
Move it to a separate ‘common/mlxml’ directory.
This is not pure refactoring. For unclear reasons, the previous
version of ‘Xml.parse_file’ read the whole file into memory and then
called ‘xmlReadMemory’. This was quite inefficient, and unnecessary
because we could use ‘xmlReadFile’ to read and parse the file
efficiently. Changing the code to use ‘xmlReadFile’ also removes the
unnecessary dependency on ‘Common_utils.read_whole_file’.
The ‘Progress’ module is a self-contained library with the only
dependencies being:
- the C ‘progress’ implementation
Move it to a separate ‘common/mlprogress’ directory.
This change is pure code refactoring.
The ‘Visit’ module is a self-contained library with the only
dependencies being:
- the C ‘visit’ implementation
- the guestfs OCaml bindings
Move it to a separate ‘common/mlvisit’ directory.
This change is not entirely refactoring. Two other fixes are made:
- remove unsafe use of CLEANUP_FREE from a function which could
raise an OCaml exception (cleanup handlers would not be called
correctly if the exception is thrown)
- don't link directly to common/visit/visit.c, but instead use
the library (common/visit/libvisit.la)
