On Thu, Feb 15, 2018 at 11:04:47AM -0800, Omar Sandoval wrote:
> From: Omar Sandoval <osan...@fb.com>
>
> Currently, users wishing to manage Btrfs filesystems programatically
> have to shell out to btrfs-progs and parse the output. This isn't ideal.
> The goal of libbtrfsutil is to provide a library version of as many of
> the operations of btrfs-progs as possible and to migrate btrfs-progs to
> use it.
>
> Rather than simply refactoring the existing btrfs-progs code, the code
> has to be written from scratch for a couple of reasons:
>
> * A lot of the btrfs-progs code was not designed with a nice library API
> in mind in terms of reusability, naming, and error reporting.
> * libbtrfsutil is licensed under the LGPL, whereas btrfs-progs is under
> the GPL, which makes it dubious to directly copy or move the code.
>
> Eventually, most of the low-level btrfs-progs code should either live in
> libbtrfsutil or the shared kernel/userspace filesystem code, and
> btrfs-progs will just be the CLI wrapper.
>
> This first commit just includes the build system changes, license,
> README, and error reporting helper.
>
> Signed-off-by: Omar Sandoval <osan...@fb.com>
> ---
> .gitignore | 2 +
> Makefile | 72 ++--
> Makefile.inc.in | 2 +-
> libbtrfsutil/COPYING | 674
> ++++++++++++++++++++++++++++++++++++++
> libbtrfsutil/COPYING.LESSER | 165 ++++++++++
> libbtrfsutil/README.md | 35 ++
> libbtrfsutil/btrfsutil.h | 76 +++++
> libbtrfsutil/btrfsutil_internal.h | 40 +++
> libbtrfsutil/errors.c | 55 ++++
> 9 files changed, 1100 insertions(+), 21 deletions(-)
> create mode 100644 libbtrfsutil/COPYING
> create mode 100644 libbtrfsutil/COPYING.LESSER
> create mode 100644 libbtrfsutil/README.md
> create mode 100644 libbtrfsutil/btrfsutil.h
> create mode 100644 libbtrfsutil/btrfsutil_internal.h
> create mode 100644 libbtrfsutil/errors.c
>
> diff --git a/.gitignore b/.gitignore
> index 8e607f6e..272d53e4 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -43,6 +43,8 @@ libbtrfs.so.0.1
> library-test
> library-test-static
> /fssum
> +/libbtrfsutil.so*
> +/libbtrfsutil.a
>
.gitignore is not part of btrfs-progs, is it?
I Skipped Makefile, the .c and .h look good to me,
Reviewed-by: Liu Bo <bo.li....@oracle.com>
Thanks,
-liubo
> /tests/*-tests-results.txt
> /tests/test-console.txt
> diff --git a/Makefile b/Makefile
> index 00e21379..7fb70d06 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -73,10 +73,20 @@ CFLAGS = $(SUBST_CFLAGS) \
> -fPIC \
> -I$(TOPDIR) \
> -I$(TOPDIR)/kernel-lib \
> + -I$(TOPDIR)/libbtrfsutil \
> $(EXTRAWARN_CFLAGS) \
> $(DEBUG_CFLAGS_INTERNAL) \
> $(EXTRA_CFLAGS)
>
> +LIBBTRFSUTIL_CFLAGS = $(SUBST_CFLAGS) \
> + $(CSTD) \
> + -D_GNU_SOURCE \
> + -fPIC \
> + -fvisibility=hidden \
> + -I$(TOPDIR)/libbtrfsutil \
> + $(EXTRAWARN_CFLAGS) \
> + $(EXTRA_CFLAGS)
> +
> LDFLAGS = $(SUBST_LDFLAGS) \
> -rdynamic -L$(TOPDIR) \
> $(DEBUG_LDFLAGS_INTERNAL) \
> @@ -121,12 +131,17 @@ libbtrfs_headers = send-stream.h send-utils.h send.h
> kernel-lib/rbtree.h btrfs-l
> kernel-lib/crc32c.h kernel-lib/list.h kerncompat.h \
> kernel-lib/radix-tree.h kernel-lib/sizes.h kernel-lib/raid56.h \
> extent-cache.h extent_io.h ioctl.h ctree.h btrfsck.h version.h
> +libbtrfsutil_major := $(shell sed -rn 's/^\#define BTRFS_UTIL_VERSION_MAJOR
> ([0-9])+$$/\1/p' libbtrfsutil/btrfsutil.h)
> +libbtrfsutil_minor := $(shell sed -rn 's/^\#define BTRFS_UTIL_VERSION_MINOR
> ([0-9])+$$/\1/p' libbtrfsutil/btrfsutil.h)
> +libbtrfsutil_patch := $(shell sed -rn 's/^\#define BTRFS_UTIL_VERSION_PATCH
> ([0-9])+$$/\1/p' libbtrfsutil/btrfsutil.h)
> +libbtrfsutil_version :=
> $(libbtrfsutil_major).$(libbtrfsutil_minor).$(libbtrfsutil_patch)
> +libbtrfsutil_objects = libbtrfsutil/errors.o
> convert_objects = convert/main.o convert/common.o convert/source-fs.o \
> convert/source-ext2.o convert/source-reiserfs.o
> mkfs_objects = mkfs/main.o mkfs/common.o mkfs/rootdir.o
> image_objects = image/main.o image/sanitize.o
> all_objects = $(objects) $(cmds_objects) $(libbtrfs_objects)
> $(convert_objects) \
> - $(mkfs_objects) $(image_objects)
> + $(mkfs_objects) $(image_objects) $(libbtrfsutil_objects)
>
> udev_rules = 64-btrfs-dm.rules
>
> @@ -246,11 +261,10 @@ static_convert_objects = $(patsubst %.o, %.static.o,
> $(convert_objects))
> static_mkfs_objects = $(patsubst %.o, %.static.o, $(mkfs_objects))
> static_image_objects = $(patsubst %.o, %.static.o, $(image_objects))
>
> -libs_shared = libbtrfs.so.0.1
> -libs_static = libbtrfs.a
> +libs_shared = libbtrfs.so.0.1 libbtrfsutil.so.$(libbtrfsutil_version)
> +libs_static = libbtrfs.a libbtrfsutil.a
> libs = $(libs_shared) $(libs_static)
> -lib_links = libbtrfs.so.0 libbtrfs.so
> -headers = $(libbtrfs_headers)
> +lib_links = libbtrfs.so.0 libbtrfs.so libbtrfsutil.so.$(libbtrfsutil_major)
> libbtrfsutil.so
>
> # make C=1 to enable sparse
> ifdef C
> @@ -287,7 +301,7 @@ endif
> $(Q)$(CC) $(STATIC_CFLAGS) -c $< -o $@ $($(subst
> -,_,$(@:%.static.o=%)-cflags)) \
> $($(subst -,_,btrfs-$(@:%/$(notdir $@)=%)-cflags))
>
> -all: $(progs) libbtrfs $(BUILDDIRS)
> +all: $(progs) $(libs) $(lib_links) $(BUILDDIRS)
> $(SUBDIRS): $(BUILDDIRS)
> $(BUILDDIRS):
> @echo "Making all in $(patsubst build-%,%,$@)"
> @@ -351,20 +365,35 @@ kernel-lib/tables.c:
> @echo " [TABLE] $@"
> $(Q)./mktables > $@ || ($(RM) -f $@ && exit 1)
>
> -libbtrfs: $(libs_shared) $(lib_links)
> +libbtrfs.so.0.1: $(libbtrfs_objects)
> + @echo " [LD] $@"
> + $(Q)$(CC) $(CFLAGS) $^ $(LDFLAGS) $(LIBBTRFS_LIBS) \
> + -shared -Wl,-soname,libbtrfs.so.0 -o $@
> +
> +libbtrfs.a: $(libbtrfs_objects)
> + @echo " [AR] $@"
> + $(Q)$(AR) cr $@ $^
> +
> +libbtrfs.so.0 libbtrfs.so: libbtrfs.so.0.1
> + @echo " [LN] $@"
> + $(Q)$(LN_S) -f $< $@
> +
> +libbtrfsutil/%.o: libbtrfsutil/%.c
> + @echo " [CC] $@"
> + $(Q)$(CC) $(LIBBTRFSUTIL_CFLAGS) -o $@ -c $< -o $@
>
> -$(libs_shared): $(libbtrfs_objects) $(lib_links) send.h
> +libbtrfsutil.so.$(libbtrfsutil_version): $(libbtrfsutil_objects)
> @echo " [LD] $@"
> - $(Q)$(CC) $(CFLAGS) $(libbtrfs_objects) $(LDFLAGS) $(LIBBTRFS_LIBS) \
> - -shared -Wl,-soname,libbtrfs.so.0 -o libbtrfs.so.0.1
> + $(Q)$(CC) $(LIBBTRFSUTIL_CFLAGS) $(libbtrfsutil_objects) \
> + -shared -Wl,-soname,libbtrfsutil.so.$(libbtrfsutil_major) -o $@
>
> -$(libs_static): $(libbtrfs_objects)
> +libbtrfsutil.a: $(libbtrfsutil_objects)
> @echo " [AR] $@"
> - $(Q)$(AR) cr libbtrfs.a $(libbtrfs_objects)
> + $(Q)$(AR) cr $@ $^
>
> -$(lib_links):
> +libbtrfsutil.so.$(libbtrfsutil_major) libbtrfsutil.so:
> libbtrfsutil.so.$(libbtrfsutil_version)
> @echo " [LN] $@"
> - $(Q)$(LN_S) -f libbtrfs.so.0.1 $@
> + $(Q)$(LN_S) -f $< $@
>
> # keep intermediate files from the below implicit rules around
> .PRECIOUS: $(addsuffix .o,$(progs))
> @@ -483,7 +512,7 @@ test-ioctl: ioctl-test ioctl-test-32 ioctl-test-64
> $(Q)./ioctl-test-32 > ioctl-test-32.log
> $(Q)./ioctl-test-64 > ioctl-test-64.log
>
> -library-test: library-test.c $(libs_shared)
> +library-test: library-test.c libbtrfs.so
> @echo " [TEST PREP] $@"$(eval TMPD=$(shell mktemp -d))
> $(Q)mkdir -p $(TMPD)/include/btrfs && \
> cp $(libbtrfs_headers) $(TMPD)/include/btrfs && \
> @@ -547,7 +576,8 @@ clean: $(CLEANDIRS)
> mktables btrfs.static mkfs.btrfs.static fssum \
> $(check_defs) \
> $(libs) $(lib_links) \
> - $(progs_static) $(progs_extra)
> + $(progs_static) $(progs_extra) \
> + libbtrfsutil/*.o libbtrfsutil/*.o.d
>
> clean-doc:
> @echo "Cleaning Documentation"
> @@ -575,8 +605,9 @@ install: $(libs) $(progs_install) $(INSTALLDIRS)
> $(INSTALL) -m755 -d $(DESTDIR)$(libdir)
> $(INSTALL) $(libs) $(DESTDIR)$(libdir)
> cp -a $(lib_links) $(DESTDIR)$(libdir)
> - $(INSTALL) -m755 -d $(DESTDIR)$(incdir)
> - $(INSTALL) -m644 $(headers) $(DESTDIR)$(incdir)
> + $(INSTALL) -m755 -d $(DESTDIR)$(incdir)/btrfs
> + $(INSTALL) -m644 $(libbtrfs_headers) $(DESTDIR)$(incdir)/btrfs
> + $(INSTALL) -m644 libbtrfsutil/btrfsutil.h $(DESTDIR)$(incdir)
> ifneq ($(udevdir),)
> $(INSTALL) -m755 -d $(DESTDIR)$(udevruledir)
> $(INSTALL) -m644 $(udev_rules) $(DESTDIR)$(udevruledir)
> @@ -594,8 +625,9 @@ $(INSTALLDIRS):
>
> uninstall:
> $(Q)$(MAKE) $(MAKEOPTS) -C Documentation uninstall
> - cd $(DESTDIR)$(incdir); $(RM) -f -- $(headers)
> - $(RMDIR) -p --ignore-fail-on-non-empty -- $(DESTDIR)$(incdir)
> + cd $(DESTDIR)$(incdir)/btrfs; $(RM) -f -- $(libbtrfs_headers)
> + $(RMDIR) -p --ignore-fail-on-non-empty -- $(DESTDIR)$(incdir)/btrfs
> + cd $(DESTDIR)$(incdir); $(RM) -f -- btrfsutil.h
> cd $(DESTDIR)$(libdir); $(RM) -f -- $(lib_links) $(libs)
> cd $(DESTDIR)$(bindir); $(RM) -f -- btrfsck fsck.btrfs $(progs_install)
>
> diff --git a/Makefile.inc.in b/Makefile.inc.in
> index 56271903..b53bef80 100644
> --- a/Makefile.inc.in
> +++ b/Makefile.inc.in
> @@ -27,7 +27,7 @@ prefix ?= @prefix@
> exec_prefix = @exec_prefix@
> bindir = @bindir@
> libdir ?= @libdir@
> -incdir = @includedir@/btrfs
> +incdir = @includedir@
> udevdir = @UDEVDIR@
> udevruledir = ${udevdir}/rules.d
>
> diff --git a/libbtrfsutil/COPYING b/libbtrfsutil/COPYING
> new file mode 100644
> index 00000000..f288702d
> --- /dev/null
> +++ b/libbtrfsutil/COPYING
> @@ -0,0 +1,674 @@
> + GNU GENERAL PUBLIC LICENSE
> + Version 3, 29 June 2007
> +
> + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
> + Everyone is permitted to copy and distribute verbatim copies
> + of this license document, but changing it is not allowed.
> +
> + Preamble
> +
> + The GNU General Public License is a free, copyleft license for
> +software and other kinds of works.
> +
> + The licenses for most software and other practical works are designed
> +to take away your freedom to share and change the works. By contrast,
> +the GNU General Public License is intended to guarantee your freedom to
> +share and change all versions of a program--to make sure it remains free
> +software for all its users. We, the Free Software Foundation, use the
> +GNU General Public License for most of our software; it applies also to
> +any other work released this way by its authors. You can apply it to
> +your programs, too.
> +
> + When we speak of free software, we are referring to freedom, not
> +price. Our General Public Licenses are designed to make sure that you
> +have the freedom to distribute copies of free software (and charge for
> +them if you wish), that you receive source code or can get it if you
> +want it, that you can change the software or use pieces of it in new
> +free programs, and that you know you can do these things.
> +
> + To protect your rights, we need to prevent others from denying you
> +these rights or asking you to surrender the rights. Therefore, you have
> +certain responsibilities if you distribute copies of the software, or if
> +you modify it: responsibilities to respect the freedom of others.
> +
> + For example, if you distribute copies of such a program, whether
> +gratis or for a fee, you must pass on to the recipients the same
> +freedoms that you received. You must make sure that they, too, receive
> +or can get the source code. And you must show them these terms so they
> +know their rights.
> +
> + Developers that use the GNU GPL protect your rights with two steps:
> +(1) assert copyright on the software, and (2) offer you this License
> +giving you legal permission to copy, distribute and/or modify it.
> +
> + For the developers' and authors' protection, the GPL clearly explains
> +that there is no warranty for this free software. For both users' and
> +authors' sake, the GPL requires that modified versions be marked as
> +changed, so that their problems will not be attributed erroneously to
> +authors of previous versions.
> +
> + Some devices are designed to deny users access to install or run
> +modified versions of the software inside them, although the manufacturer
> +can do so. This is fundamentally incompatible with the aim of
> +protecting users' freedom to change the software. The systematic
> +pattern of such abuse occurs in the area of products for individuals to
> +use, which is precisely where it is most unacceptable. Therefore, we
> +have designed this version of the GPL to prohibit the practice for those
> +products. If such problems arise substantially in other domains, we
> +stand ready to extend this provision to those domains in future versions
> +of the GPL, as needed to protect the freedom of users.
> +
> + Finally, every program is threatened constantly by software patents.
> +States should not allow patents to restrict development and use of
> +software on general-purpose computers, but in those that do, we wish to
> +avoid the special danger that patents applied to a free program could
> +make it effectively proprietary. To prevent this, the GPL assures that
> +patents cannot be used to render the program non-free.
> +
> + The precise terms and conditions for copying, distribution and
> +modification follow.
> +
> + TERMS AND CONDITIONS
> +
> + 0. Definitions.
> +
> + "This License" refers to version 3 of the GNU General Public License.
> +
> + "Copyright" also means copyright-like laws that apply to other kinds of
> +works, such as semiconductor masks.
> +
> + "The Program" refers to any copyrightable work licensed under this
> +License. Each licensee is addressed as "you". "Licensees" and
> +"recipients" may be individuals or organizations.
> +
> + To "modify" a work means to copy from or adapt all or part of the work
> +in a fashion requiring copyright permission, other than the making of an
> +exact copy. The resulting work is called a "modified version" of the
> +earlier work or a work "based on" the earlier work.
> +
> + A "covered work" means either the unmodified Program or a work based
> +on the Program.
> +
> + To "propagate" a work means to do anything with it that, without
> +permission, would make you directly or secondarily liable for
> +infringement under applicable copyright law, except executing it on a
> +computer or modifying a private copy. Propagation includes copying,
> +distribution (with or without modification), making available to the
> +public, and in some countries other activities as well.
> +
> + To "convey" a work means any kind of propagation that enables other
> +parties to make or receive copies. Mere interaction with a user through
> +a computer network, with no transfer of a copy, is not conveying.
> +
> + An interactive user interface displays "Appropriate Legal Notices"
> +to the extent that it includes a convenient and prominently visible
> +feature that (1) displays an appropriate copyright notice, and (2)
> +tells the user that there is no warranty for the work (except to the
> +extent that warranties are provided), that licensees may convey the
> +work under this License, and how to view a copy of this License. If
> +the interface presents a list of user commands or options, such as a
> +menu, a prominent item in the list meets this criterion.
> +
> + 1. Source Code.
> +
> + The "source code" for a work means the preferred form of the work
> +for making modifications to it. "Object code" means any non-source
> +form of a work.
> +
> + A "Standard Interface" means an interface that either is an official
> +standard defined by a recognized standards body, or, in the case of
> +interfaces specified for a particular programming language, one that
> +is widely used among developers working in that language.
> +
> + The "System Libraries" of an executable work include anything, other
> +than the work as a whole, that (a) is included in the normal form of
> +packaging a Major Component, but which is not part of that Major
> +Component, and (b) serves only to enable use of the work with that
> +Major Component, or to implement a Standard Interface for which an
> +implementation is available to the public in source code form. A
> +"Major Component", in this context, means a major essential component
> +(kernel, window system, and so on) of the specific operating system
> +(if any) on which the executable work runs, or a compiler used to
> +produce the work, or an object code interpreter used to run it.
> +
> + The "Corresponding Source" for a work in object code form means all
> +the source code needed to generate, install, and (for an executable
> +work) run the object code and to modify the work, including scripts to
> +control those activities. However, it does not include the work's
> +System Libraries, or general-purpose tools or generally available free
> +programs which are used unmodified in performing those activities but
> +which are not part of the work. For example, Corresponding Source
> +includes interface definition files associated with source files for
> +the work, and the source code for shared libraries and dynamically
> +linked subprograms that the work is specifically designed to require,
> +such as by intimate data communication or control flow between those
> +subprograms and other parts of the work.
> +
> + The Corresponding Source need not include anything that users
> +can regenerate automatically from other parts of the Corresponding
> +Source.
> +
> + The Corresponding Source for a work in source code form is that
> +same work.
> +
> + 2. Basic Permissions.
> +
> + All rights granted under this License are granted for the term of
> +copyright on the Program, and are irrevocable provided the stated
> +conditions are met. This License explicitly affirms your unlimited
> +permission to run the unmodified Program. The output from running a
> +covered work is covered by this License only if the output, given its
> +content, constitutes a covered work. This License acknowledges your
> +rights of fair use or other equivalent, as provided by copyright law.
> +
> + You may make, run and propagate covered works that you do not
> +convey, without conditions so long as your license otherwise remains
> +in force. You may convey covered works to others for the sole purpose
> +of having them make modifications exclusively for you, or provide you
> +with facilities for running those works, provided that you comply with
> +the terms of this License in conveying all material for which you do
> +not control copyright. Those thus making or running the covered works
> +for you must do so exclusively on your behalf, under your direction
> +and control, on terms that prohibit them from making any copies of
> +your copyrighted material outside their relationship with you.
> +
> + Conveying under any other circumstances is permitted solely under
> +the conditions stated below. Sublicensing is not allowed; section 10
> +makes it unnecessary.
> +
> + 3. Protecting Users' Legal Rights From Anti-Circumvention Law.
> +
> + No covered work shall be deemed part of an effective technological
> +measure under any applicable law fulfilling obligations under article
> +11 of the WIPO copyright treaty adopted on 20 December 1996, or
> +similar laws prohibiting or restricting circumvention of such
> +measures.
> +
> + When you convey a covered work, you waive any legal power to forbid
> +circumvention of technological measures to the extent such circumvention
> +is effected by exercising rights under this License with respect to
> +the covered work, and you disclaim any intention to limit operation or
> +modification of the work as a means of enforcing, against the work's
> +users, your or third parties' legal rights to forbid circumvention of
> +technological measures.
> +
> + 4. Conveying Verbatim Copies.
> +
> + You may convey verbatim copies of the Program's source code as you
> +receive it, in any medium, provided that you conspicuously and
> +appropriately publish on each copy an appropriate copyright notice;
> +keep intact all notices stating that this License and any
> +non-permissive terms added in accord with section 7 apply to the code;
> +keep intact all notices of the absence of any warranty; and give all
> +recipients a copy of this License along with the Program.
> +
> + You may charge any price or no price for each copy that you convey,
> +and you may offer support or warranty protection for a fee.
> +
> + 5. Conveying Modified Source Versions.
> +
> + You may convey a work based on the Program, or the modifications to
> +produce it from the Program, in the form of source code under the
> +terms of section 4, provided that you also meet all of these conditions:
> +
> + a) The work must carry prominent notices stating that you modified
> + it, and giving a relevant date.
> +
> + b) The work must carry prominent notices stating that it is
> + released under this License and any conditions added under section
> + 7. This requirement modifies the requirement in section 4 to
> + "keep intact all notices".
> +
> + c) You must license the entire work, as a whole, under this
> + License to anyone who comes into possession of a copy. This
> + License will therefore apply, along with any applicable section 7
> + additional terms, to the whole of the work, and all its parts,
> + regardless of how they are packaged. This License gives no
> + permission to license the work in any other way, but it does not
> + invalidate such permission if you have separately received it.
> +
> + d) If the work has interactive user interfaces, each must display
> + Appropriate Legal Notices; however, if the Program has interactive
> + interfaces that do not display Appropriate Legal Notices, your
> + work need not make them do so.
> +
> + A compilation of a covered work with other separate and independent
> +works, which are not by their nature extensions of the covered work,
> +and which are not combined with it such as to form a larger program,
> +in or on a volume of a storage or distribution medium, is called an
> +"aggregate" if the compilation and its resulting copyright are not
> +used to limit the access or legal rights of the compilation's users
> +beyond what the individual works permit. Inclusion of a covered work
> +in an aggregate does not cause this License to apply to the other
> +parts of the aggregate.
> +
> + 6. Conveying Non-Source Forms.
> +
> + You may convey a covered work in object code form under the terms
> +of sections 4 and 5, provided that you also convey the
> +machine-readable Corresponding Source under the terms of this License,
> +in one of these ways:
> +
> + a) Convey the object code in, or embodied in, a physical product
> + (including a physical distribution medium), accompanied by the
> + Corresponding Source fixed on a durable physical medium
> + customarily used for software interchange.
> +
> + b) Convey the object code in, or embodied in, a physical product
> + (including a physical distribution medium), accompanied by a
> + written offer, valid for at least three years and valid for as
> + long as you offer spare parts or customer support for that product
> + model, to give anyone who possesses the object code either (1) a
> + copy of the Corresponding Source for all the software in the
> + product that is covered by this License, on a durable physical
> + medium customarily used for software interchange, for a price no
> + more than your reasonable cost of physically performing this
> + conveying of source, or (2) access to copy the
> + Corresponding Source from a network server at no charge.
> +
> + c) Convey individual copies of the object code with a copy of the
> + written offer to provide the Corresponding Source. This
> + alternative is allowed only occasionally and noncommercially, and
> + only if you received the object code with such an offer, in accord
> + with subsection 6b.
> +
> + d) Convey the object code by offering access from a designated
> + place (gratis or for a charge), and offer equivalent access to the
> + Corresponding Source in the same way through the same place at no
> + further charge. You need not require recipients to copy the
> + Corresponding Source along with the object code. If the place to
> + copy the object code is a network server, the Corresponding Source
> + may be on a different server (operated by you or a third party)
> + that supports equivalent copying facilities, provided you maintain
> + clear directions next to the object code saying where to find the
> + Corresponding Source. Regardless of what server hosts the
> + Corresponding Source, you remain obligated to ensure that it is
> + available for as long as needed to satisfy these requirements.
> +
> + e) Convey the object code using peer-to-peer transmission, provided
> + you inform other peers where the object code and Corresponding
> + Source of the work are being offered to the general public at no
> + charge under subsection 6d.
> +
> + A separable portion of the object code, whose source code is excluded
> +from the Corresponding Source as a System Library, need not be
> +included in conveying the object code work.
> +
> + A "User Product" is either (1) a "consumer product", which means any
> +tangible personal property which is normally used for personal, family,
> +or household purposes, or (2) anything designed or sold for incorporation
> +into a dwelling. In determining whether a product is a consumer product,
> +doubtful cases shall be resolved in favor of coverage. For a particular
> +product received by a particular user, "normally used" refers to a
> +typical or common use of that class of product, regardless of the status
> +of the particular user or of the way in which the particular user
> +actually uses, or expects or is expected to use, the product. A product
> +is a consumer product regardless of whether the product has substantial
> +commercial, industrial or non-consumer uses, unless such uses represent
> +the only significant mode of use of the product.
> +
> + "Installation Information" for a User Product means any methods,
> +procedures, authorization keys, or other information required to install
> +and execute modified versions of a covered work in that User Product from
> +a modified version of its Corresponding Source. The information must
> +suffice to ensure that the continued functioning of the modified object
> +code is in no case prevented or interfered with solely because
> +modification has been made.
> +
> + If you convey an object code work under this section in, or with, or
> +specifically for use in, a User Product, and the conveying occurs as
> +part of a transaction in which the right of possession and use of the
> +User Product is transferred to the recipient in perpetuity or for a
> +fixed term (regardless of how the transaction is characterized), the
> +Corresponding Source conveyed under this section must be accompanied
> +by the Installation Information. But this requirement does not apply
> +if neither you nor any third party retains the ability to install
> +modified object code on the User Product (for example, the work has
> +been installed in ROM).
> +
> + The requirement to provide Installation Information does not include a
> +requirement to continue to provide support service, warranty, or updates
> +for a work that has been modified or installed by the recipient, or for
> +the User Product in which it has been modified or installed. Access to a
> +network may be denied when the modification itself materially and
> +adversely affects the operation of the network or violates the rules and
> +protocols for communication across the network.
> +
> + Corresponding Source conveyed, and Installation Information provided,
> +in accord with this section must be in a format that is publicly
> +documented (and with an implementation available to the public in
> +source code form), and must require no special password or key for
> +unpacking, reading or copying.
> +
> + 7. Additional Terms.
> +
> + "Additional permissions" are terms that supplement the terms of this
> +License by making exceptions from one or more of its conditions.
> +Additional permissions that are applicable to the entire Program shall
> +be treated as though they were included in this License, to the extent
> +that they are valid under applicable law. If additional permissions
> +apply only to part of the Program, that part may be used separately
> +under those permissions, but the entire Program remains governed by
> +this License without regard to the additional permissions.
> +
> + When you convey a copy of a covered work, you may at your option
> +remove any additional permissions from that copy, or from any part of
> +it. (Additional permissions may be written to require their own
> +removal in certain cases when you modify the work.) You may place
> +additional permissions on material, added by you to a covered work,
> +for which you have or can give appropriate copyright permission.
> +
> + Notwithstanding any other provision of this License, for material you
> +add to a covered work, you may (if authorized by the copyright holders of
> +that material) supplement the terms of this License with terms:
> +
> + a) Disclaiming warranty or limiting liability differently from the
> + terms of sections 15 and 16 of this License; or
> +
> + b) Requiring preservation of specified reasonable legal notices or
> + author attributions in that material or in the Appropriate Legal
> + Notices displayed by works containing it; or
> +
> + c) Prohibiting misrepresentation of the origin of that material, or
> + requiring that modified versions of such material be marked in
> + reasonable ways as different from the original version; or
> +
> + d) Limiting the use for publicity purposes of names of licensors or
> + authors of the material; or
> +
> + e) Declining to grant rights under trademark law for use of some
> + trade names, trademarks, or service marks; or
> +
> + f) Requiring indemnification of licensors and authors of that
> + material by anyone who conveys the material (or modified versions of
> + it) with contractual assumptions of liability to the recipient, for
> + any liability that these contractual assumptions directly impose on
> + those licensors and authors.
> +
> + All other non-permissive additional terms are considered "further
> +restrictions" within the meaning of section 10. If the Program as you
> +received it, or any part of it, contains a notice stating that it is
> +governed by this License along with a term that is a further
> +restriction, you may remove that term. If a license document contains
> +a further restriction but permits relicensing or conveying under this
> +License, you may add to a covered work material governed by the terms
> +of that license document, provided that the further restriction does
> +not survive such relicensing or conveying.
> +
> + If you add terms to a covered work in accord with this section, you
> +must place, in the relevant source files, a statement of the
> +additional terms that apply to those files, or a notice indicating
> +where to find the applicable terms.
> +
> + Additional terms, permissive or non-permissive, may be stated in the
> +form of a separately written license, or stated as exceptions;
> +the above requirements apply either way.
> +
> + 8. Termination.
> +
> + You may not propagate or modify a covered work except as expressly
> +provided under this License. Any attempt otherwise to propagate or
> +modify it is void, and will automatically terminate your rights under
> +this License (including any patent licenses granted under the third
> +paragraph of section 11).
> +
> + However, if you cease all violation of this License, then your
> +license from a particular copyright holder is reinstated (a)
> +provisionally, unless and until the copyright holder explicitly and
> +finally terminates your license, and (b) permanently, if the copyright
> +holder fails to notify you of the violation by some reasonable means
> +prior to 60 days after the cessation.
> +
> + Moreover, your license from a particular copyright holder is
> +reinstated permanently if the copyright holder notifies you of the
> +violation by some reasonable means, this is the first time you have
> +received notice of violation of this License (for any work) from that
> +copyright holder, and you cure the violation prior to 30 days after
> +your receipt of the notice.
> +
> + Termination of your rights under this section does not terminate the
> +licenses of parties who have received copies or rights from you under
> +this License. If your rights have been terminated and not permanently
> +reinstated, you do not qualify to receive new licenses for the same
> +material under section 10.
> +
> + 9. Acceptance Not Required for Having Copies.
> +
> + You are not required to accept this License in order to receive or
> +run a copy of the Program. Ancillary propagation of a covered work
> +occurring solely as a consequence of using peer-to-peer transmission
> +to receive a copy likewise does not require acceptance. However,
> +nothing other than this License grants you permission to propagate or
> +modify any covered work. These actions infringe copyright if you do
> +not accept this License. Therefore, by modifying or propagating a
> +covered work, you indicate your acceptance of this License to do so.
> +
> + 10. Automatic Licensing of Downstream Recipients.
> +
> + Each time you convey a covered work, the recipient automatically
> +receives a license from the original licensors, to run, modify and
> +propagate that work, subject to this License. You are not responsible
> +for enforcing compliance by third parties with this License.
> +
> + An "entity transaction" is a transaction transferring control of an
> +organization, or substantially all assets of one, or subdividing an
> +organization, or merging organizations. If propagation of a covered
> +work results from an entity transaction, each party to that
> +transaction who receives a copy of the work also receives whatever
> +licenses to the work the party's predecessor in interest had or could
> +give under the previous paragraph, plus a right to possession of the
> +Corresponding Source of the work from the predecessor in interest, if
> +the predecessor has it or can get it with reasonable efforts.
> +
> + You may not impose any further restrictions on the exercise of the
> +rights granted or affirmed under this License. For example, you may
> +not impose a license fee, royalty, or other charge for exercise of
> +rights granted under this License, and you may not initiate litigation
> +(including a cross-claim or counterclaim in a lawsuit) alleging that
> +any patent claim is infringed by making, using, selling, offering for
> +sale, or importing the Program or any portion of it.
> +
> + 11. Patents.
> +
> + A "contributor" is a copyright holder who authorizes use under this
> +License of the Program or a work on which the Program is based. The
> +work thus licensed is called the contributor's "contributor version".
> +
> + A contributor's "essential patent claims" are all patent claims
> +owned or controlled by the contributor, whether already acquired or
> +hereafter acquired, that would be infringed by some manner, permitted
> +by this License, of making, using, or selling its contributor version,
> +but do not include claims that would be infringed only as a
> +consequence of further modification of the contributor version. For
> +purposes of this definition, "control" includes the right to grant
> +patent sublicenses in a manner consistent with the requirements of
> +this License.
> +
> + Each contributor grants you a non-exclusive, worldwide, royalty-free
> +patent license under the contributor's essential patent claims, to
> +make, use, sell, offer for sale, import and otherwise run, modify and
> +propagate the contents of its contributor version.
> +
> + In the following three paragraphs, a "patent license" is any express
> +agreement or commitment, however denominated, not to enforce a patent
> +(such as an express permission to practice a patent or covenant not to
> +sue for patent infringement). To "grant" such a patent license to a
> +party means to make such an agreement or commitment not to enforce a
> +patent against the party.
> +
> + If you convey a covered work, knowingly relying on a patent license,
> +and the Corresponding Source of the work is not available for anyone
> +to copy, free of charge and under the terms of this License, through a
> +publicly available network server or other readily accessible means,
> +then you must either (1) cause the Corresponding Source to be so
> +available, or (2) arrange to deprive yourself of the benefit of the
> +patent license for this particular work, or (3) arrange, in a manner
> +consistent with the requirements of this License, to extend the patent
> +license to downstream recipients. "Knowingly relying" means you have
> +actual knowledge that, but for the patent license, your conveying the
> +covered work in a country, or your recipient's use of the covered work
> +in a country, would infringe one or more identifiable patents in that
> +country that you have reason to believe are valid.
> +
> + If, pursuant to or in connection with a single transaction or
> +arrangement, you convey, or propagate by procuring conveyance of, a
> +covered work, and grant a patent license to some of the parties
> +receiving the covered work authorizing them to use, propagate, modify
> +or convey a specific copy of the covered work, then the patent license
> +you grant is automatically extended to all recipients of the covered
> +work and works based on it.
> +
> + A patent license is "discriminatory" if it does not include within
> +the scope of its coverage, prohibits the exercise of, or is
> +conditioned on the non-exercise of one or more of the rights that are
> +specifically granted under this License. You may not convey a covered
> +work if you are a party to an arrangement with a third party that is
> +in the business of distributing software, under which you make payment
> +to the third party based on the extent of your activity of conveying
> +the work, and under which the third party grants, to any of the
> +parties who would receive the covered work from you, a discriminatory
> +patent license (a) in connection with copies of the covered work
> +conveyed by you (or copies made from those copies), or (b) primarily
> +for and in connection with specific products or compilations that
> +contain the covered work, unless you entered into that arrangement,
> +or that patent license was granted, prior to 28 March 2007.
> +
> + Nothing in this License shall be construed as excluding or limiting
> +any implied license or other defenses to infringement that may
> +otherwise be available to you under applicable patent law.
> +
> + 12. No Surrender of Others' Freedom.
> +
> + If conditions are imposed on you (whether by court order, agreement or
> +otherwise) that contradict the conditions of this License, they do not
> +excuse you from the conditions of this License. If you cannot convey a
> +covered work so as to satisfy simultaneously your obligations under this
> +License and any other pertinent obligations, then as a consequence you may
> +not convey it at all. For example, if you agree to terms that obligate you
> +to collect a royalty for further conveying from those to whom you convey
> +the Program, the only way you could satisfy both those terms and this
> +License would be to refrain entirely from conveying the Program.
> +
> + 13. Use with the GNU Affero General Public License.
> +
> + Notwithstanding any other provision of this License, you have
> +permission to link or combine any covered work with a work licensed
> +under version 3 of the GNU Affero General Public License into a single
> +combined work, and to convey the resulting work. The terms of this
> +License will continue to apply to the part which is the covered work,
> +but the special requirements of the GNU Affero General Public License,
> +section 13, concerning interaction through a network will apply to the
> +combination as such.
> +
> + 14. Revised Versions of this License.
> +
> + The Free Software Foundation may publish revised and/or new versions of
> +the GNU General Public License from time to time. Such new versions will
> +be similar in spirit to the present version, but may differ in detail to
> +address new problems or concerns.
> +
> + Each version is given a distinguishing version number. If the
> +Program specifies that a certain numbered version of the GNU General
> +Public License "or any later version" applies to it, you have the
> +option of following the terms and conditions either of that numbered
> +version or of any later version published by the Free Software
> +Foundation. If the Program does not specify a version number of the
> +GNU General Public License, you may choose any version ever published
> +by the Free Software Foundation.
> +
> + If the Program specifies that a proxy can decide which future
> +versions of the GNU General Public License can be used, that proxy's
> +public statement of acceptance of a version permanently authorizes you
> +to choose that version for the Program.
> +
> + Later license versions may give you additional or different
> +permissions. However, no additional obligations are imposed on any
> +author or copyright holder as a result of your choosing to follow a
> +later version.
> +
> + 15. Disclaimer of Warranty.
> +
> + THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
> +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
> +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
> +OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
> +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
> +PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
> +IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
> +ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
> +
> + 16. Limitation of Liability.
> +
> + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
> +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
> +THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
> +GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
> +USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
> +DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
> +PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
> +EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
> +SUCH DAMAGES.
> +
> + 17. Interpretation of Sections 15 and 16.
> +
> + If the disclaimer of warranty and limitation of liability provided
> +above cannot be given local legal effect according to their terms,
> +reviewing courts shall apply local law that most closely approximates
> +an absolute waiver of all civil liability in connection with the
> +Program, unless a warranty or assumption of liability accompanies a
> +copy of the Program in return for a fee.
> +
> + END OF TERMS AND CONDITIONS
> +
> + How to Apply These Terms to Your New Programs
> +
> + If you develop a new program, and you want it to be of the greatest
> +possible use to the public, the best way to achieve this is to make it
> +free software which everyone can redistribute and change under these terms.
> +
> + To do so, attach the following notices to the program. It is safest
> +to attach them to the start of each source file to most effectively
> +state the exclusion of warranty; and each file should have at least
> +the "copyright" line and a pointer to where the full notice is found.
> +
> + <one line to give the program's name and a brief idea of what it does.>
> + Copyright (C) <year> <name of author>
> +
> + This program is free software: you can redistribute it and/or modify
> + it under the terms of the GNU General Public License as published by
> + the Free Software Foundation, either version 3 of the License, or
> + (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <https://www.gnu.org/licenses/>.
> +
> +Also add information on how to contact you by electronic and paper mail.
> +
> + If the program does terminal interaction, make it output a short
> +notice like this when it starts in an interactive mode:
> +
> + <program> Copyright (C) <year> <name of author>
> + This program comes with ABSOLUTELY NO WARRANTY; for details type `show
> w'.
> + This is free software, and you are welcome to redistribute it
> + under certain conditions; type `show c' for details.
> +
> +The hypothetical commands `show w' and `show c' should show the appropriate
> +parts of the General Public License. Of course, your program's commands
> +might be different; for a GUI interface, you would use an "about box".
> +
> + You should also get your employer (if you work as a programmer) or school,
> +if any, to sign a "copyright disclaimer" for the program, if necessary.
> +For more information on this, and how to apply and follow the GNU GPL, see
> +<https://www.gnu.org/licenses/>.
> +
> + The GNU General Public License does not permit incorporating your program
> +into proprietary programs. If your program is a subroutine library, you
> +may consider it more useful to permit linking proprietary applications with
> +the library. If this is what you want to do, use the GNU Lesser General
> +Public License instead of this License. But first, please read
> +<https://www.gnu.org/licenses/why-not-lgpl.html>.
> diff --git a/libbtrfsutil/COPYING.LESSER b/libbtrfsutil/COPYING.LESSER
> new file mode 100644
> index 00000000..0a041280
> --- /dev/null
> +++ b/libbtrfsutil/COPYING.LESSER
> @@ -0,0 +1,165 @@
> + GNU LESSER GENERAL PUBLIC LICENSE
> + Version 3, 29 June 2007
> +
> + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
> + Everyone is permitted to copy and distribute verbatim copies
> + of this license document, but changing it is not allowed.
> +
> +
> + This version of the GNU Lesser General Public License incorporates
> +the terms and conditions of version 3 of the GNU General Public
> +License, supplemented by the additional permissions listed below.
> +
> + 0. Additional Definitions.
> +
> + As used herein, "this License" refers to version 3 of the GNU Lesser
> +General Public License, and the "GNU GPL" refers to version 3 of the GNU
> +General Public License.
> +
> + "The Library" refers to a covered work governed by this License,
> +other than an Application or a Combined Work as defined below.
> +
> + An "Application" is any work that makes use of an interface provided
> +by the Library, but which is not otherwise based on the Library.
> +Defining a subclass of a class defined by the Library is deemed a mode
> +of using an interface provided by the Library.
> +
> + A "Combined Work" is a work produced by combining or linking an
> +Application with the Library. The particular version of the Library
> +with which the Combined Work was made is also called the "Linked
> +Version".
> +
> + The "Minimal Corresponding Source" for a Combined Work means the
> +Corresponding Source for the Combined Work, excluding any source code
> +for portions of the Combined Work that, considered in isolation, are
> +based on the Application, and not on the Linked Version.
> +
> + The "Corresponding Application Code" for a Combined Work means the
> +object code and/or source code for the Application, including any data
> +and utility programs needed for reproducing the Combined Work from the
> +Application, but excluding the System Libraries of the Combined Work.
> +
> + 1. Exception to Section 3 of the GNU GPL.
> +
> + You may convey a covered work under sections 3 and 4 of this License
> +without being bound by section 3 of the GNU GPL.
> +
> + 2. Conveying Modified Versions.
> +
> + If you modify a copy of the Library, and, in your modifications, a
> +facility refers to a function or data to be supplied by an Application
> +that uses the facility (other than as an argument passed when the
> +facility is invoked), then you may convey a copy of the modified
> +version:
> +
> + a) under this License, provided that you make a good faith effort to
> + ensure that, in the event an Application does not supply the
> + function or data, the facility still operates, and performs
> + whatever part of its purpose remains meaningful, or
> +
> + b) under the GNU GPL, with none of the additional permissions of
> + this License applicable to that copy.
> +
> + 3. Object Code Incorporating Material from Library Header Files.
> +
> + The object code form of an Application may incorporate material from
> +a header file that is part of the Library. You may convey such object
> +code under terms of your choice, provided that, if the incorporated
> +material is not limited to numerical parameters, data structure
> +layouts and accessors, or small macros, inline functions and templates
> +(ten or fewer lines in length), you do both of the following:
> +
> + a) Give prominent notice with each copy of the object code that the
> + Library is used in it and that the Library and its use are
> + covered by this License.
> +
> + b) Accompany the object code with a copy of the GNU GPL and this license
> + document.
> +
> + 4. Combined Works.
> +
> + You may convey a Combined Work under terms of your choice that,
> +taken together, effectively do not restrict modification of the
> +portions of the Library contained in the Combined Work and reverse
> +engineering for debugging such modifications, if you also do each of
> +the following:
> +
> + a) Give prominent notice with each copy of the Combined Work that
> + the Library is used in it and that the Library and its use are
> + covered by this License.
> +
> + b) Accompany the Combined Work with a copy of the GNU GPL and this license
> + document.
> +
> + c) For a Combined Work that displays copyright notices during
> + execution, include the copyright notice for the Library among
> + these notices, as well as a reference directing the user to the
> + copies of the GNU GPL and this license document.
> +
> + d) Do one of the following:
> +
> + 0) Convey the Minimal Corresponding Source under the terms of this
> + License, and the Corresponding Application Code in a form
> + suitable for, and under terms that permit, the user to
> + recombine or relink the Application with a modified version of
> + the Linked Version to produce a modified Combined Work, in the
> + manner specified by section 6 of the GNU GPL for conveying
> + Corresponding Source.
> +
> + 1) Use a suitable shared library mechanism for linking with the
> + Library. A suitable mechanism is one that (a) uses at run time
> + a copy of the Library already present on the user's computer
> + system, and (b) will operate properly with a modified version
> + of the Library that is interface-compatible with the Linked
> + Version.
> +
> + e) Provide Installation Information, but only if you would otherwise
> + be required to provide such information under section 6 of the
> + GNU GPL, and only to the extent that such information is
> + necessary to install and execute a modified version of the
> + Combined Work produced by recombining or relinking the
> + Application with a modified version of the Linked Version. (If
> + you use option 4d0, the Installation Information must accompany
> + the Minimal Corresponding Source and Corresponding Application
> + Code. If you use option 4d1, you must provide the Installation
> + Information in the manner specified by section 6 of the GNU GPL
> + for conveying Corresponding Source.)
> +
> + 5. Combined Libraries.
> +
> + You may place library facilities that are a work based on the
> +Library side by side in a single library together with other library
> +facilities that are not Applications and are not covered by this
> +License, and convey such a combined library under terms of your
> +choice, if you do both of the following:
> +
> + a) Accompany the combined library with a copy of the same work based
> + on the Library, uncombined with any other library facilities,
> + conveyed under the terms of this License.
> +
> + b) Give prominent notice with the combined library that part of it
> + is a work based on the Library, and explaining where to find the
> + accompanying uncombined form of the same work.
> +
> + 6. Revised Versions of the GNU Lesser General Public License.
> +
> + The Free Software Foundation may publish revised and/or new versions
> +of the GNU Lesser General Public License from time to time. Such new
> +versions will be similar in spirit to the present version, but may
> +differ in detail to address new problems or concerns.
> +
> + Each version is given a distinguishing version number. If the
> +Library as you received it specifies that a certain numbered version
> +of the GNU Lesser General Public License "or any later version"
> +applies to it, you have the option of following the terms and
> +conditions either of that published version or of any later version
> +published by the Free Software Foundation. If the Library as you
> +received it does not specify a version number of the GNU Lesser
> +General Public License, you may choose any version of the GNU Lesser
> +General Public License ever published by the Free Software Foundation.
> +
> + If the Library as you received it specifies that a proxy can decide
> +whether future versions of the GNU Lesser General Public License shall
> +apply, that proxy's public statement of acceptance of any version is
> +permanent authorization for you to choose that version for the
> +Library.
> diff --git a/libbtrfsutil/README.md b/libbtrfsutil/README.md
> new file mode 100644
> index 00000000..ee4c6a1d
> --- /dev/null
> +++ b/libbtrfsutil/README.md
> @@ -0,0 +1,35 @@
> +libbtrfsutil
> +============
> +
> +libbtrfsutil is a library for managing Btrfs filesystems. It is licensed
> under
> +the LGPL. libbtrfsutil provides interfaces for a subset of the operations
> +offered by the `btrfs` command line utility.
> +
> +Development
> +-----------
> +
> +The [development process for btrfs-progs](../README.md#development) applies.
> +
> +libbtrfsutil only includes operations that are done through the filesystem
> and
> +ioctl interface, not operations that modify the filesystem directly (e.g.,
> mkfs
> +or fsck). This is by design but also a legal necessity, as the filesystem
> +implementation is GPL but libbtrfsutil is LGPL. That is also why the
> +libbtrfsutil code is a reimplementation of the btrfs-progs code rather than a
> +refactoring. Be wary of this when porting functionality.
> +
> +libbtrfsutil is semantically versioned separately from btrfs-progs. It is the
> +maintainers' responsibility to bump the version as needed (at most once per
> +release of btrfs-progs).
> +
> +A few guidelines:
> +
> +* All interfaces must be documented in `btrfsutil.h` using the kernel-doc
> style
> +* Error codes should be specific about what _exactly_ failed
> +* Functions should have a path and an fd variant whenever possible
> +* Spell out terms in function names, etc. rather than abbreviating whenever
> + possible
> +* Don't require the Btrfs UAPI headers for any interfaces (e.g., instead of
> + directly exposing a type from `linux/btrfs_tree.h`, abstract it away in a
> + type specific to `libbtrfsutil`)
> +* Preserve API and ABI compatability at all times (i.e., we don't want to
> bump
> + the library major version if we don't have to)
> diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h
> new file mode 100644
> index 00000000..867418f2
> --- /dev/null
> +++ b/libbtrfsutil/btrfsutil.h
> @@ -0,0 +1,76 @@
> +/*
> + * Copyright (C) 2018 Facebook
> + *
> + * This file is part of libbtrfsutil.
> + *
> + * libbtrfsutil is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License as published
> by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * libbtrfsutil is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public License
> + * along with libbtrfsutil. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef BTRFS_UTIL_H
> +#define BTRFS_UTIL_H
> +
> +#define BTRFS_UTIL_VERSION_MAJOR 1
> +#define BTRFS_UTIL_VERSION_MINOR 0
> +#define BTRFS_UTIL_VERSION_PATCH 0
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +/**
> + * enum btrfs_util_error - libbtrfsutil error codes.
> + *
> + * All functions in libbtrfsutil that can return an error return this type
> and
> + * set errno.
> + */
> +enum btrfs_util_error {
> + BTRFS_UTIL_OK,
> + BTRFS_UTIL_ERROR_STOP_ITERATION,
> + BTRFS_UTIL_ERROR_NO_MEMORY,
> + BTRFS_UTIL_ERROR_INVALID_ARGUMENT,
> + BTRFS_UTIL_ERROR_NOT_BTRFS,
> + BTRFS_UTIL_ERROR_NOT_SUBVOLUME,
> + BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND,
> + BTRFS_UTIL_ERROR_OPEN_FAILED,
> + BTRFS_UTIL_ERROR_RMDIR_FAILED,
> + BTRFS_UTIL_ERROR_UNLINK_FAILED,
> + BTRFS_UTIL_ERROR_STAT_FAILED,
> + BTRFS_UTIL_ERROR_STATFS_FAILED,
> + BTRFS_UTIL_ERROR_SEARCH_FAILED,
> + BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED,
> + BTRFS_UTIL_ERROR_SUBVOL_GETFLAGS_FAILED,
> + BTRFS_UTIL_ERROR_SUBVOL_SETFLAGS_FAILED,
> + BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED,
> + BTRFS_UTIL_ERROR_SNAP_CREATE_FAILED,
> + BTRFS_UTIL_ERROR_SNAP_DESTROY_FAILED,
> + BTRFS_UTIL_ERROR_DEFAULT_SUBVOL_FAILED,
> + BTRFS_UTIL_ERROR_SYNC_FAILED,
> + BTRFS_UTIL_ERROR_START_SYNC_FAILED,
> + BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED,
> +};
> +
> +/**
> + * btrfs_util_strerror() - Convert a libtrfsutil error code to a string
> + * description.
> + * @err: The error to convert.
> + *
> + * Return: Error description.
> + */
> +const char *btrfs_util_strerror(enum btrfs_util_error err);
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif /* BTRFS_UTIL_H */
> diff --git a/libbtrfsutil/btrfsutil_internal.h
> b/libbtrfsutil/btrfsutil_internal.h
> new file mode 100644
> index 00000000..bdf8840a
> --- /dev/null
> +++ b/libbtrfsutil/btrfsutil_internal.h
> @@ -0,0 +1,40 @@
> +/*
> + * Copyright (C) 2018 Facebook
> + *
> + * This file is part of libbtrfsutil.
> + *
> + * libbtrfsutil is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License as published
> by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * libbtrfsutil is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public License
> + * along with libbtrfsutil. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef BTRFS_UTIL_INTERNAL_H
> +#define BTRFS_UTIL_INTERNAL_H
> +
> +#include <asm/byteorder.h>
> +
> +#include "btrfsutil.h"
> +
> +#define PUBLIC __attribute__((visibility("default")))
> +
> +#define le16_to_cpu __le16_to_cpu
> +#define le32_to_cpu __le32_to_cpu
> +#define le64_to_cpu __le64_to_cpu
> +
> +#define SAVE_ERRNO_AND_CLOSE(fd) { \
> + int saved_errno = errno; \
> + \
> + close(fd); \
> + errno = saved_errno; \
> +}
> +
> +#endif /* BTRFS_UTIL_INTERNAL_H */
> diff --git a/libbtrfsutil/errors.c b/libbtrfsutil/errors.c
> new file mode 100644
> index 00000000..634edc65
> --- /dev/null
> +++ b/libbtrfsutil/errors.c
> @@ -0,0 +1,55 @@
> +/*
> + * Copyright (C) 2018 Facebook
> + *
> + * This file is part of libbtrfsutil.
> + *
> + * libbtrfsutil is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License as published
> by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * libbtrfsutil is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public License
> + * along with libbtrfsutil. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <stddef.h>
> +
> +#include "btrfsutil_internal.h"
> +
> +static const char * const error_messages[] = {
> + [BTRFS_UTIL_OK] = "Success",
> + [BTRFS_UTIL_ERROR_STOP_ITERATION] = "Stop iteration",
> + [BTRFS_UTIL_ERROR_NO_MEMORY] = "Cannot allocate memory",
> + [BTRFS_UTIL_ERROR_INVALID_ARGUMENT] = "Invalid argument",
> + [BTRFS_UTIL_ERROR_NOT_BTRFS] = "Not a Btrfs filesystem",
> + [BTRFS_UTIL_ERROR_NOT_SUBVOLUME] = "Not a Btrfs subvolume",
> + [BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND] = "Subvolume not found",
> + [BTRFS_UTIL_ERROR_OPEN_FAILED] = "Could not open",
> + [BTRFS_UTIL_ERROR_RMDIR_FAILED] = "Could not rmdir",
> + [BTRFS_UTIL_ERROR_UNLINK_FAILED] = "Could not unlink",
> + [BTRFS_UTIL_ERROR_STAT_FAILED] = "Could not stat",
> + [BTRFS_UTIL_ERROR_STATFS_FAILED] = "Could not statfs",
> + [BTRFS_UTIL_ERROR_SEARCH_FAILED] = "Could not search B-tree",
> + [BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED] = "Could not lookup inode",
> + [BTRFS_UTIL_ERROR_SUBVOL_GETFLAGS_FAILED] = "Could not get subvolume
> flags",
> + [BTRFS_UTIL_ERROR_SUBVOL_SETFLAGS_FAILED] = "Could not set subvolume
> flags",
> + [BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED] = "Could not create subvolume",
> + [BTRFS_UTIL_ERROR_SNAP_CREATE_FAILED] = "Could not create snapshot",
> + [BTRFS_UTIL_ERROR_SNAP_DESTROY_FAILED] = "Could not destroy
> subvolume/snapshot",
> + [BTRFS_UTIL_ERROR_DEFAULT_SUBVOL_FAILED] = "Could not set default
> subvolume",
> + [BTRFS_UTIL_ERROR_SYNC_FAILED] = "Could not sync filesystem",
> + [BTRFS_UTIL_ERROR_START_SYNC_FAILED] = "Could not start filesystem
> sync",
> + [BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED] = "Could not wait for filesystem
> sync",
> +};
> +
> +PUBLIC const char *btrfs_util_strerror(enum btrfs_util_error err)
> +{
> + if (err < 0 || err >= sizeof(error_messages) /
> sizeof(error_messages[0]))
> + return NULL;
> + return error_messages[err];
> +}
> --
> 2.16.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
