Simplify ELF parsing logic by exiting early, as there is no common clean
up path to execute. That makes it unnecessary to track when err was set
and when it was cleared. It also reduces nesting in some places.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
As a preparation for adding BTF-based BPF map loading, extract .BTF and
.BTF.ext loading logic.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Multiple files in libbpf redefine their own definitions for min/max.
Let's define them in libbpf_internal.h and use those everywhere.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Kernel internally checks that either key or value type ID is specified,
before using btf_fd. Do the same in libbpf's map creation code for
determining when to retry map creation w/o BTF.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: fba01a0689a9 ("libbpf: use negative fd to specify missing BTF")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
There are a bunch of lines of code or comments that are unnecessary
wrapped into multi-lines. Fix that without violating any code
guidelines.
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Extra check for type is unnecessary in first case.
Extra zeroing is unnecessary, as snprintf guarantees that it will
zero-terminate string.
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
0 is a valid FD, so it's better to initialize it to -1, as is done in
other places. Also, technically, BTF type ID 0 is valid (it's a VOID
type), so it's more reliable to check btf_fd, instead of
btf_key_type_id, to determine if there is any BTF associated with a map.
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Validate there was no error retrieving symbol name corresponding to
a BPF map.
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Rewrite endianness check to use "more canonical" way, using
compiler-defined macros, similar to few other places in libbpf. It also
is more obvious and shorter.
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
pr_warning ultimately may call into user-provided callback function,
which can clobber errno value, so we need to save it before that.
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Ensure that size of a section w/ BPF instruction is exactly a multiple
of BPF instruction size.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
BTF contains enough type information to allow generating valid
compilable C header w/ correct layout of structs/unions and all the
typedef/enum definitions. This patch adds a new "object" - btf_dump to
facilitate dumping BTF as valid C. btf_dump__dump_type() is the main API
which takes care of dumping out (through user-provided printf-like
callback function) C definitions for given type ID and it's required
dependencies. This allows for not just dumping out entirety of BTF types,
but also selective filtering based on user-provided criterias w/ minimal
set of dependent types.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is a need for fast point lookups inside libbpf for multiple use
cases (e.g., name resolution for BTF-to-C conversion, by-name lookups in
BTF for upcoming BPF CO-RE relocation support, etc). This patch
implements simple resizable non-thread safe hashmap using single linked
list chains.
Four different insert strategies are supported:
- HASHMAP_ADD - only add key/value if key doesn't exist yet;
- HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
update value;
- HASHMAP_UPDATE - update value, if key already exists; otherwise, do
nothing and return -ENOENT;
- HASHMAP_APPEND - always add key/value pair, even if key already exists.
This turns hashmap into a multimap by allowing multiple values to be
associated with the same key. Most useful read API for such hashmap is
hashmap__for_each_key_entry() iteration. If hashmap__find() is still
used, it will return last inserted key/value entry (first in a bucket
chain).
For HASHMAP_SET and HASHMAP_UPDATE, old key/value pair is returned, so
that calling code can handle proper memory management, if necessary.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Loading BTF and BTF.ext from ELF file is a common need. Instead of
requiring every user to re-implement it, let's provide this API from
libbpf itself. It's mostly copy/paste from `bpftool btf dump`
implementation, which will be switched to libbpf's version in next
patch. btf__parse_elf allows to load BTF and optionally BTF.ext.
This is also useful for tests that need to load/work with BTF, loaded
from test ELF files.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
libbpf_internal.h expects a bunch of stuff defined in libbpf.h to be
defined. This patch makes sure that libbpf.h is always included.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
libbpf_util.h header was recently exposed as public as a dependency of
xsk.h. In addition to memory barriers, it contained logging helpers,
which are not supposed to be exposed. This patch moves those into
libbpf_internal.h, which is kept as an internal header.
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Fixes: 7080da890984 ("libbpf: add libbpf_util.h to header install.")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Depending on used versions of libbpf, Clang, and kernel, it's possible to
have valid BPF object files with valid BTF information, that still won't
load successfully due to Clang emitting newer BTF features (e.g.,
BTF_KIND_FUNC, .BTF.ext's line_info/func_info, BTF_KIND_DATASEC, etc), that
are not yet supported by older kernel.
This patch adds detection of BTF features and sanitizes BPF object's BTF
by substituting various supported BTF kinds, which have compatible layout:
- BTF_KIND_FUNC -> BTF_KIND_TYPEDEF
- BTF_KIND_FUNC_PROTO -> BTF_KIND_ENUM
- BTF_KIND_VAR -> BTF_KIND_INT
- BTF_KIND_DATASEC -> BTF_KIND_STRUCT
Replacement is done in such a way as to preserve as much information as
possible (names, sizes, etc) where possible without violating kernel's
validation rules.
v2->v3:
- remove duplicate #defines from libbpf_util.h
v1->v2:
- add internal libbpf_internal.h w/ common stuff
- switch SK storage BTF to use new libbpf__probe_raw_btf()
Reported-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
After making Github recognize README.md as markdown text,
there are a bunch of formatting problems. They are fixed in this commit.
Singed-off-by: Andrii Nakryiko <andriin@fb.com>
Using %ld for printing out value of ptrdiff_t type is not portable
between 32-bit and 64-bit archs. This is causing compilation errors for
libbpf on 32-bit platform (discovered as part of an effort to integrate
libbpf into systemd ([0])). Proper formatter is %td, which is used in
this patch.
v2->v1:
- add Reported-by
- provide more context on how this issue was discovered
[0] https://github.com/systemd/systemd/pull/12151
Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds support for VAR and DATASEC in btf_dedup(). VAR/DATASEC
are never deduplicated, but they need to be processed anyway as types
they refer to might need to be remapped due to deduplication and
compaction.
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Yonghong Song <yhs@fb.com>
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
1. There is one commit ("libbpf: fix btf_dedup equivalence check
handling of different kinds"), which was originally committed into bpf
tree and manually synced into libbpf (it was a critical bug fix). Now
that bpf and bpf-next trees were merged, this causes duplicate commits in
libbpf. To address this, check is added to see if libbpf repo already has
a commit with the same subject and allow to skip it.
2. Just checking by subject is not good enough, as we currently have few
different commits with the same subject "bpf: Sync bpf.h to tools/".
To address this, script now will ask user whether to skip or cherry-pick
commit. This allows for human to double-check the commit and make
informed devision.
3. There is a commit ('bfb35c27c65f bpf: fix whitespace for ENCAP_L2
defines in bpf.h'), which modifies both include/uapi/linux/bpf.h and
tools/include/uapi/linux/bpf.h in the same commit. This break the
sync script, as it doesn't cherry-pick commits that hasn't modified
libbpf files. So at the time that commit bfb35c27c65f is applied, linux
repo is missing some preceding changes to include/uapi/linux/bpf.h. They
would normally be ignored later during repo filtering, but to do
cherry-pick they are necessary. It's hard to fix it automatically, so
script will wait for user to resolve the issue and continue.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
btf_dedup_is_equiv() used to compare btf_type->info fields, before doing
kind-specific equivalence check. This comparsion implicitly verified
that candidate and canonical types are of the same kind. With enum fwd
resolution logic this check couldn't be done generically anymore, as for
enums info contains vlen, which differs between enum fwd and
fully-defined enum, so this check was subsumed by kind-specific
equivalence checks.
This change caused btf_dedup_is_equiv() to let through VOID vs other
types check to reach switch, which was never meant to be handing VOID
kind, as VOID kind is always pre-resolved to itself and is only
equivalent to itself, which is checked early in btf_dedup_is_equiv().
This change adds back BTF kind equality check in place of more generic
btf_type->info check, still defering further kind-specific checks to
a per-kind switch.
Fixes: 9768095ba97c ("btf: resolve enum fwds in btf_dedup")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Merges are common. `git cherry-pick` can't cherry-pick merge commit and
requires specifying which of the parents should be cherry-picked, so
it's a pain. But merges are also commonly empty, so it's safe to skip them.
This change goes through all merges touching libbpf files, checks that
they don't have any conflict resolution diffs. If there are any, abort,
if not, proceed as usual, ignoring merges.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
GCC and clang support enum forward declarations as an extension. Such
forward-declared enums will be represented as normal BTF_KIND_ENUM types with
vlen=0. This patch adds ability to resolve such enums to their corresponding
fully defined enums. This helps to avoid duplicated BTF type graphs which only
differ by some types referencing forward-declared enum vs full enum.
One such example in kernel is enum irqchip_irq_state, defined in
include/linux/interrupt.h and forward-declared in include/linux/irq.h. This
causes entire struct task_struct and all referenced types to be duplicated in
btf_dedup output. This patch eliminates such duplication cases.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch splits and cleans up error handling logic for loading BTF data.
Previously, if BTF data was parsed successfully, but failed to load into
kernel, we'd report nonsensical error code, instead of error returned from
btf__load(). Now btf__new() and btf__load() are handled separately with proper
cleanup and warning reporting.
Fixes: d29d87f7e612 ("btf: separate btf creation and loading")
Reported-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
With xsk.{o,h} changes we started including Linux UAPI's if_xdp.h
header. We need to sync it along the other UAPI headers.
Also updated README to reflect this.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
This patch makes sure we build AF_XDP-related code as part of libbpf. This
also required copying few uapi/linux headers and adding few used definitions
in include headers.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
When checking available canonical candidates for struct/union algorithm
utilizes btf_dedup_is_equiv to determine if candidate is suitable. This
check is not enough when candidate is corresponding FWD for that
struct/union, because according to equivalence logic they are
equivalent. When it so happens that FWD and STRUCT/UNION end in hashing
to the same bucket, it's possible to create remapping loop from FWD to
STRUCT and STRUCT to same FWD, which will cause btf_dedup() to loop
forever.
This patch fixes the issue by additionally checking that type and
canonical candidate are strictly equal (utilizing btf_equal_struct).
Fixes: d5caef5b5655 ("btf: add BTF types deduplication algorithm")
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Default size of dedup table (16k) is good enough for most binaries, even
typical vmlinux images. But there are cases of binaries with huge amount
of BTF types (e.g., allyesconfig variants of kernel), which benefit from
having bigger dedup table size to lower amount of unnecessary hash
collisions. Tools like pahole, thus, can tune this parameter to reach
optimal performance.
This change also serves double purpose of allowing tests to force hash
collisions to test some corner cases, used in follow up patch.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Andrii Nakryiko