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2022-03-17libbpf: Add subskeleton scaffoldingDelyan Kratunov1-0/+29
In symmetry with bpf_object__open_skeleton(), bpf_object__open_subskeleton() performs the actual walking and linking of maps, progs, and globals described by bpf_*_skeleton objects. Signed-off-by: Delyan Kratunov <delyank@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/6942a46fbe20e7ebf970affcca307ba616985b15.1647473511.git.delyank@fb.com
2022-03-17libbpf: Add bpf_program__attach_kprobe_multi_opts functionJiri Olsa1-0/+23
Adding bpf_program__attach_kprobe_multi_opts function for attaching kprobe program to multiple functions. struct bpf_link * bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, const char *pattern, const struct bpf_kprobe_multi_opts *opts); User can specify functions to attach with 'pattern' argument that allows wildcards (*?' supported) or provide symbols or addresses directly through opts argument. These 3 options are mutually exclusive. When using symbols or addresses, user can also provide cookie value for each symbol/address that can be retrieved later in bpf program with bpf_get_attach_cookie helper. struct bpf_kprobe_multi_opts { size_t sz; const char **syms; const unsigned long *addrs; const __u64 *cookies; size_t cnt; bool retprobe; size_t :0; }; Symbols, addresses and cookies are provided through opts object (syms/addrs/cookies) as array pointers with specified count (cnt). Each cookie value is paired with provided function address or symbol with the same array index. The program can be also attached as return probe if 'retprobe' is set. For quick usage with NULL opts argument, like: bpf_program__attach_kprobe_multi_opts(prog, "ksys_*", NULL) the 'prog' will be attached as kprobe to 'ksys_*' functions. Also adding new program sections for automatic attachment: kprobe.multi/<symbol_pattern> kretprobe.multi/<symbol_pattern> The symbol_pattern is used as 'pattern' argument in bpf_program__attach_kprobe_multi_opts function. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220316122419.933957-10-jolsa@kernel.org
2022-03-05libbpf: Support custom SEC() handlersAndrii Nakryiko1-0/+109
Allow registering and unregistering custom handlers for BPF program. This allows user applications and libraries to plug into libbpf's declarative SEC() definition handling logic. This allows to offload complex and intricate custom logic into external libraries, but still provide a great user experience. One such example is USDT handling library, which has a lot of code and complexity which doesn't make sense to put into libbpf directly, but it would be really great for users to be able to specify BPF programs with something like SEC("usdt/<path-to-binary>:<usdt_provider>:<usdt_name>") and have correct BPF program type set (BPF_PROGRAM_TYPE_KPROBE, as it is uprobe) and even support BPF skeleton's auto-attach logic. In some cases, it might be even good idea to override libbpf's default handling, like for SEC("perf_event") programs. With custom library, it's possible to extend logic to support specifying perf event specification right there in SEC() definition without burdening libbpf with lots of custom logic or extra library dependecies (e.g., libpfm4). With current patch it's possible to override libbpf's SEC("perf_event") handling and specify a completely custom ones. Further, it's possible to specify a generic fallback handling for any SEC() that doesn't match any other custom or standard libbpf handlers. This allows to accommodate whatever legacy use cases there might be, if necessary. See doc comments for libbpf_register_prog_handler() and libbpf_unregister_prog_handler() for detailed semantics. This patch also bumps libbpf development version to v0.8 and adds new APIs there. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20220305010129.1549719-3-andrii@kernel.org
2022-02-03libbpf: Deprecate priv/set_priv storageDelyan Kratunov1-1/+6
Arbitrary storage via bpf_*__set_priv/__priv is being deprecated without a replacement ([1]). perf uses this capability, but most of that is going away with the removal of prologue generation ([2]). perf is already suppressing deprecation warnings, so the remaining cleanup will happen separately. [1]: Closes: https://github.com/libbpf/libbpf/issues/294 [2]: https://lore.kernel.org/bpf/20220123221932.537060-1-jolsa@kernel.org/ Signed-off-by: Delyan Kratunov <delyank@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220203180032.1921580-1-delyank@fb.com
2022-01-25libbpf: deprecate bpf_program__is_<type>() and bpf_program__set_<type>() APIsAndrii Nakryiko1-0/+26
Not sure why these APIs were added in the first place instead of a completely generic (and not requiring constantly adding new APIs with each new BPF program type) bpf_program__type() and bpf_program__set_type() APIs. But as it is right now, there are 13 such specialized is_type/set_type APIs, while latest kernel is already at 30+ BPF program types. Instead of completing the set of APIs and keep chasing kernel's bpf_prog_type enum, deprecate existing subset and recommend generic bpf_program__type() and bpf_program__set_type() APIs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220124194254.2051434-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-25libbpf: deprecate bpf_map__resize()Andrii Nakryiko1-0/+1
Deprecated bpf_map__resize() in favor of bpf_map__set_max_entries() setter. In addition to having a surprising name (users often don't realize that they need to use bpf_map__resize()), the name also implies some magic way of resizing BPF map after it is created, which is clearly not the case. Another minor annoyance is that bpf_map__resize() disallows 0 value for max_entries, which in some cases is totally acceptable (e.g., like for BPF perf buf case to let libbpf auto-create one buffer per each available CPU core). [0] Closes: https://github.com/libbpf/libbpf/issues/304 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220124194254.2051434-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-25libbpf: hide and discourage inconsistently named gettersAndrii Nakryiko1-3/+2
Move a bunch of "getters" into libbpf_legacy.h to keep them there in libbpf 1.0. See [0] for discussion of "Discouraged APIs". These getters don't add any maintenance burden and are simple alias, but they are inconsistent in naming. So keep them in libbpf_legacy.h instead of libbpf.h to "hide" them in favor of preferred getters ([1]). Also add two missing getters: bpf_program__type() and bpf_program__expected_attach_type(). [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#handling-deprecation-of-apis-and-functionality [1] Closes: https://github.com/libbpf/libbpf/issues/307 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220124194254.2051434-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-24libbpf: Mark bpf_object__open_xattr() deprecatedChristy Lee1-0/+1
Mark bpf_object__open_xattr() as deprecated, use bpf_object__open_file() instead. [0] Closes: https://github.com/libbpf/libbpf/issues/287 Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220125010917.679975-1-christylee@fb.com
2022-01-24libbpf: Mark bpf_object__open_buffer() API deprecatedChristy Lee1-0/+1
Deprecate bpf_object__open_buffer() API in favor of the unified opts-based bpf_object__open_mem() API. Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220125005923.418339-2-christylee@fb.com
2022-01-20libbpf: streamline low-level XDP APIsAndrii Nakryiko1-0/+29
Introduce 4 new netlink-based XDP APIs for attaching, detaching, and querying XDP programs: - bpf_xdp_attach; - bpf_xdp_detach; - bpf_xdp_query; - bpf_xdp_query_id. These APIs replace bpf_set_link_xdp_fd, bpf_set_link_xdp_fd_opts, bpf_get_link_xdp_id, and bpf_get_link_xdp_info APIs ([0]). The latter don't follow a consistent naming pattern and some of them use non-extensible approaches (e.g., struct xdp_link_info which can't be modified without breaking libbpf ABI). The approach I took with these low-level XDP APIs is similar to what we did with low-level TC APIs. There is a nice duality of bpf_tc_attach vs bpf_xdp_attach, and so on. I left bpf_xdp_attach() to support detaching when -1 is specified for prog_fd for generality and convenience, but bpf_xdp_detach() is preferred due to clearer naming and associated semantics. Both bpf_xdp_attach() and bpf_xdp_detach() accept the same opts struct allowing to specify expected old_prog_fd. While doing the refactoring, I noticed that old APIs require users to specify opts with old_fd == -1 to declare "don't care about already attached XDP prog fd" condition. Otherwise, FD 0 is assumed, which is essentially never an intended behavior. So I made this behavior consistent with other kernel and libbpf APIs, in which zero FD means "no FD". This seems to be more in line with the latest thinking in BPF land and should cause less user confusion, hopefully. For querying, I left two APIs, both more generic bpf_xdp_query() allowing to query multiple IDs and attach mode, but also a specialization of it, bpf_xdp_query_id(), which returns only requested prog_id. Uses of prog_id returning bpf_get_link_xdp_id() were so prevalent across selftests and samples, that it seemed a very common use case and using bpf_xdp_query() for doing it felt very cumbersome with a highly branches if/else chain based on flags and attach mode. Old APIs are scheduled for deprecation in libbpf 0.8 release. [0] Closes: https://github.com/libbpf/libbpf/issues/309 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/r/20220120061422.2710637-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-12libbpf: Deprecate bpf_map__def() APIChristy Lee1-1/+2
All fields accessed via bpf_map_def can now be accessed via appropirate getters and setters. Mark bpf_map__def() API as deprecated. Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220108004218.355761-6-christylee@fb.com
2022-01-05libbpf 1.0: Deprecate bpf_object__find_map_by_offset() APIChristy Lee1-1/+2
API created with simplistic assumptions about BPF map definitions. It hasn’t worked for a while, deprecate it in preparation for libbpf 1.0. [0] Closes: https://github.com/libbpf/libbpf/issues/302 Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220105003120.2222673-1-christylee@fb.com
2022-01-05libbpf 1.0: Deprecate bpf_map__is_offload_neutral()Christy Lee1-0/+1
Deprecate bpf_map__is_offload_neutral(). It’s most probably broken already. PERF_EVENT_ARRAY isn’t the only map that’s not suitable for hardware offloading. Applications can directly check map type instead. [0] Closes: https://github.com/libbpf/libbpf/issues/306 Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220105000601.2090044-1-christylee@fb.com
2022-01-05libbpf: Deprecate bpf_perf_event_read_simple() APIChristy Lee1-0/+1
With perf_buffer__poll() and perf_buffer__consume() APIs available, there is no reason to expose bpf_perf_event_read_simple() API to users. If users need custom perf buffer, they could re-implement the function. Mark bpf_perf_event_read_simple() and move the logic to a new static function so it can still be called by other functions in the same file. [0] Closes: https://github.com/libbpf/libbpf/issues/310 Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211229204156.13569-1-christylee@fb.com
2021-12-17libbpf: Rework feature-probing APIsAndrii Nakryiko1-4/+48
Create three extensible alternatives to inconsistently named feature-probing APIs: - libbpf_probe_bpf_prog_type() instead of bpf_probe_prog_type(); - libbpf_probe_bpf_map_type() instead of bpf_probe_map_type(); - libbpf_probe_bpf_helper() instead of bpf_probe_helper(). Set up return values such that libbpf can report errors (e.g., if some combination of input arguments isn't possible to validate, etc), in addition to whether the feature is supported (return value 1) or not supported (return value 0). Also schedule deprecation of those three APIs. Also schedule deprecation of bpf_probe_large_insn_limit(). Also fix all the existing detection logic for various program and map types that never worked: - BPF_PROG_TYPE_LIRC_MODE2; - BPF_PROG_TYPE_TRACING; - BPF_PROG_TYPE_LSM; - BPF_PROG_TYPE_EXT; - BPF_PROG_TYPE_SYSCALL; - BPF_PROG_TYPE_STRUCT_OPS; - BPF_MAP_TYPE_STRUCT_OPS; - BPF_MAP_TYPE_BLOOM_FILTER. Above prog/map types needed special setups and detection logic to work. Subsequent patch adds selftests that will make sure that all the detection logic keeps working for all current and future program and map types, avoiding otherwise inevitable bit rot. [0] Closes: https://github.com/libbpf/libbpf/issues/312 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Cc: Julia Kartseva <hex@fb.com> Link: https://lore.kernel.org/bpf/20211217171202.3352835-2-andrii@kernel.org
2021-12-14libbpf: Mark bpf_object__find_program_by_title API deprecated.Kui-Feng Lee1-0/+1
Deprecate this API since v0.7. All callers should move to bpf_object__find_program_by_name if possible, otherwise use bpf_object__for_each_program to find a program out from a given section. [0] Closes: https://github.com/libbpf/libbpf/issues/292 Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211214035931.1148209-5-kuifeng@fb.com
2021-12-13libbpf: Add doc comments for bpf_program__(un)pin()Grant Seltzer1-0/+24
This adds doc comments for the two bpf_program pinning functions, bpf_program__pin() and bpf_program__unpin() Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211209232222.541733-1-grantseltzer@gmail.com
2021-12-10libbpf: Deprecate bpf_object__load_xattr()Andrii Nakryiko1-0/+1
Deprecate non-extensible bpf_object__load_xattr() in v0.8 ([0]). With log_level control through bpf_object_open_opts or bpf_program__set_log_level(), we are finally at the point where bpf_object__load_xattr() doesn't provide any functionality that can't be accessed through other (better) ways. The other feature, target_btf_path, is also controllable through bpf_object_open_opts. [0] Closes: https://github.com/libbpf/libbpf/issues/289 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211209193840.1248570-9-andrii@kernel.org
2021-12-10libbpf: Add per-program log buffer setter and getterAndrii Nakryiko1-0/+7
Allow to set user-provided log buffer on a per-program basis ([0]). This gives great deal of flexibility in terms of which programs are loaded with logging enabled and where corresponding logs go. Log buffer set with bpf_program__set_log_buf() overrides kernel_log_buf and kernel_log_size settings set at bpf_object open time through bpf_object_open_opts, if any. Adjust bpf_object_load_prog_instance() logic to not perform own log buf allocation and load retry if custom log buffer is provided by the user. [0] Closes: https://github.com/libbpf/libbpf/issues/418 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211209193840.1248570-8-andrii@kernel.org
2021-12-10libbpf: Allow passing user log setting through bpf_object_open_optsAndrii Nakryiko1-1/+40
Allow users to provide their own custom log_buf, log_size, and log_level at bpf_object level through bpf_object_open_opts. This log_buf will be used during BTF loading. Subsequent patch will use same log_buf during BPF program loading, unless overriden at per-bpf_program level. When such custom log_buf is provided, libbpf won't be attempting retrying loading of BTF to try to provide its own log buffer to capture kernel's error log output. User is responsible to provide big enough buffer, otherwise they run a risk of getting -ENOSPC error from the bpf() syscall. See also comments in bpf_object_open_opts regarding log_level and log_buf interactions. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211209193840.1248570-5-andrii@kernel.org
2021-12-06libbpf: Add doc comments in libbpf.hGrant Seltzer1-0/+53
This adds comments above functions in libbpf.h which document their uses. These comments are of a format that doxygen and sphinx can pick up and render. These are rendered by libbpf.readthedocs.org These doc comments are for: - bpf_object__open_file() - bpf_object__open_mem() - bpf_program__attach_uprobe() - bpf_program__attach_uprobe_opts() Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211206203709.332530-1-grantseltzer@gmail.com
2021-12-06libbpf: Fix trivial typohuangxuesen1-2/+2
Fix typo in comment from 'bpf_skeleton_map' to 'bpf_map_skeleton' and from 'bpf_skeleton_prog' to 'bpf_prog_skeleton'. Signed-off-by: huangxuesen <huangxuesen@kuaishou.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1638755236-3851199-1-git-send-email-hxseverything@gmail.com
2021-12-02libbpf: Deprecate bpf_prog_load_xattr() APIAndrii Nakryiko1-0/+1
bpf_prog_load_xattr() is high-level API that's named as a low-level BPF_PROG_LOAD wrapper APIs, but it actually operates on struct bpf_object. It's badly and confusingly misnamed as it will load all the progs insige bpf_object, returning prog_fd of the very first BPF program. It also has a bunch of ad-hoc things like log_level override, map_ifindex auto-setting, etc. All this can be expressed more explicitly and cleanly through existing libbpf APIs. This patch marks bpf_prog_load_xattr() for deprecation in libbpf v0.8 ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/308 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211201232824.3166325-10-andrii@kernel.org
2021-12-02libbpf: Add API to get/set log_level at per-program levelAndrii Nakryiko1-0/+2
Add bpf_program__set_log_level() and bpf_program__log_level() to fetch and adjust log_level sent during BPF_PROG_LOAD command. This allows to selectively request more or less verbose output in BPF verifier log. Also bump libbpf version to 0.7 and make these APIs the first in v0.7. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211201232824.3166325-3-andrii@kernel.org
2021-11-19libbpf: Change bpf_program__set_extra_flags to bpf_program__set_flagsFlorent Revest1-1/+1
bpf_program__set_extra_flags has just been introduced so we can still change it without breaking users. This new interface is a bit more flexible (for example if someone wants to clear a flag). Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211119180035.1396139-1-revest@chromium.org
2021-11-19libbpf: Add runtime APIs to query libbpf versionAndrii Nakryiko1-0/+4
Libbpf provided LIBBPF_MAJOR_VERSION and LIBBPF_MINOR_VERSION macros to check libbpf version at compilation time. This doesn't cover all the needs, though, because version of libbpf that application is compiled against doesn't necessarily match the version of libbpf at runtime, especially if libbpf is used as a shared library. Add libbpf_major_version() and libbpf_minor_version() returning major and minor versions, respectively, as integers. Also add a convenience libbpf_version_string() for various tooling using libbpf to print out libbpf version in a human-readable form. Currently it will return "v0.6", but in the future it can contains some extra information, so the format itself is not part of a stable API and shouldn't be relied upon. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20211118174054.2699477-1-andrii@kernel.org
2021-11-11libbpf: Make perf_buffer__new() use OPTS-based interfaceAndrii Nakryiko1-13/+73
Add new variants of perf_buffer__new() and perf_buffer__new_raw() that use OPTS-based options for future extensibility ([0]). Given all the currently used API names are best fits, re-use them and use ___libbpf_override() approach and symbol versioning to preserve ABI and source code compatibility. struct perf_buffer_opts and struct perf_buffer_raw_opts are kept as well, but they are restructured such that they are OPTS-based when used with new APIs. For struct perf_buffer_raw_opts we keep few fields intact, so we have to also preserve the memory location of them both when used as OPTS and for legacy API variants. This is achieved with anonymous padding for OPTS "incarnation" of the struct. These pads can be eventually used for new options. [0] Closes: https://github.com/libbpf/libbpf/issues/311 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-6-andrii@kernel.org
2021-11-11libbpf: Add ability to get/set per-program load flagsAndrii Nakryiko1-0/+3
Add bpf_program__flags() API to retrieve prog_flags that will be (or were) supplied to BPF_PROG_LOAD command. Also add bpf_program__set_extra_flags() API to allow to set *extra* flags, in addition to those determined by program's SEC() definition. Such flags are logically OR'ed with libbpf-derived flags. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111051758.92283-2-andrii@kernel.org
2021-11-07libbpf: Remove deprecation attribute from struct bpf_prog_prep_resultAndrii Nakryiko1-1/+0
This deprecation annotation has no effect because for struct deprecation attribute has to be declared after struct definition. But instead of moving it to the end of struct definition, remove it. When deprecation will go in effect at libbpf v0.7, this deprecation attribute will cause libbpf's own source code compilation to trigger deprecation warnings, which is unavoidable because libbpf still has to support that API. So keep deprecation of APIs, but don't mark structs used in API as deprecated. Fixes: e21d585cb3db ("libbpf: Deprecate multi-instance bpf_program APIs") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20211103220845.2676888-8-andrii@kernel.org
2021-11-07libbpf: Unify low-level BPF_PROG_LOAD APIs into bpf_prog_load()Andrii Nakryiko1-2/+3
Add a new unified OPTS-based low-level API for program loading, bpf_prog_load() ([0]). bpf_prog_load() accepts few "mandatory" parameters as input arguments (program type, name, license, instructions) and all the other optional (as in not required to specify for all types of BPF programs) fields into struct bpf_prog_load_opts. This makes all the other non-extensible APIs variant for BPF_PROG_LOAD obsolete and they are slated for deprecation in libbpf v0.7: - bpf_load_program(); - bpf_load_program_xattr(); - bpf_verify_program(). Implementation-wise, internal helper libbpf__bpf_prog_load is refactored to become a public bpf_prog_load() API. struct bpf_prog_load_params used internally is replaced by public struct bpf_prog_load_opts. Unfortunately, while conceptually all this is pretty straightforward, the biggest complication comes from the already existing bpf_prog_load() *high-level* API, which has nothing to do with BPF_PROG_LOAD command. We try really hard to have a new API named bpf_prog_load(), though, because it maps naturally to BPF_PROG_LOAD command. For that, we rename old bpf_prog_load() into bpf_prog_load_deprecated() and mark it as COMPAT_VERSION() for shared library users compiled against old version of libbpf. Statically linked users and shared lib users compiled against new version of libbpf headers will get "rerouted" to bpf_prog_deprecated() through a macro helper that decides whether to use new or old bpf_prog_load() based on number of input arguments (see ___libbpf_overload in libbpf_common.h). To test that existing bpf_prog_load()-using code compiles and works as expected, I've compiled and ran selftests as is. I had to remove (locally) selftest/bpf/Makefile -Dbpf_prog_load=bpf_prog_test_load hack because it was conflicting with the macro-based overload approach. I don't expect anyone else to do something like this in practice, though. This is testing-specific way to replace bpf_prog_load() calls with special testing variant of it, which adds extra prog_flags value. After testing I kept this selftests hack, but ensured that we use a new bpf_prog_load_deprecated name for this. This patch also marks bpf_prog_load() and bpf_prog_load_xattr() as deprecated. bpf_object interface has to be used for working with struct bpf_program. Libbpf doesn't support loading just a bpf_program. The silver lining is that when we get to libbpf 1.0 all these complication will be gone and we'll have one clean bpf_prog_load() low-level API with no backwards compatibility hackery surrounding it. [0] Closes: https://github.com/libbpf/libbpf/issues/284 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-4-andrii@kernel.org
2021-11-03libbpf: Deprecate bpf_program__load() APIAndrii Nakryiko1-2/+2
Mark bpf_program__load() as deprecated ([0]) since v0.6. Also rename few internal program loading bpf_object helper functions to have more consistent naming. [0] Closes: https://github.com/libbpf/libbpf/issues/301 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103051449.1884903-1-andrii@kernel.org
2021-11-03libbpf: Deprecate bpf_program__get_prog_info_linearDave Marchevsky1-0/+3
As part of the road to libbpf 1.0, and discussed in libbpf issue tracker [0], bpf_program__get_prog_info_linear and its associated structs and helper functions should be deprecated. The functionality is too specific to the needs of 'perf', and there's little/no out-of-tree usage to preclude introduction of a more general helper in the future. [0] Closes: https://github.com/libbpf/libbpf/issues/313 Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211101224357.2651181-5-davemarchevsky@fb.com
2021-10-28libbpf: Add "map_extra" as a per-map-type extra flagJoanne Koong1-0/+3
This patch adds the libbpf infrastructure for supporting a per-map-type "map_extra" field, whose definition will be idiosyncratic depending on map type. For example, for the bloom filter map, the lower 4 bits of map_extra is used to denote the number of hash functions. Please note that until libbpf 1.0 is here, the "bpf_create_map_params" struct is used as a temporary means for propagating the map_extra field to the kernel. Signed-off-by: Joanne Koong <joannekoong@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211027234504.30744-3-joannekoong@fb.com
2021-10-27libbpf: Deprecate bpf_objects_listJoe Burton1-1/+2
Add a flag to `enum libbpf_strict_mode' to disable the global `bpf_objects_list', preventing race conditions when concurrent threads call bpf_object__open() or bpf_object__close(). bpf_object__next() will return NULL if this option is set. Callers may achieve the same workflow by tracking bpf_objects in application code. [0] Closes: https://github.com/libbpf/libbpf/issues/293 Signed-off-by: Joe Burton <jevburton@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211026223528.413950-1-jevburton.kernel@gmail.com
2021-10-25libbpf: Deprecate ambiguously-named bpf_program__size() APIAndrii Nakryiko1-0/+1
The name of the API doesn't convey clearly that this size is in number of bytes (there needed to be a separate comment to make this clear in libbpf.h). Further, measuring the size of BPF program in bytes is not exactly the best fit, because BPF programs always consist of 8-byte instructions. As such, bpf_program__insn_cnt() is a better alternative in pretty much any imaginable case. So schedule bpf_program__size() deprecation starting from v0.7 and it will be removed in libbpf 1.0. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211025224531.1088894-5-andrii@kernel.org
2021-10-25libbpf: Deprecate multi-instance bpf_program APIsAndrii Nakryiko1-1/+5
Schedule deprecation of a set of APIs that are related to multi-instance bpf_programs: - bpf_program__set_prep() ([0]); - bpf_program__{set,unset}_instance() ([1]); - bpf_program__nth_fd(). These APIs are obscure, very niche, and don't seem to be used much in practice. bpf_program__set_prep() is pretty useless for anything but the simplest BPF programs, as it doesn't allow to adjust BPF program load attributes, among other things. In short, it already bitrotted and will bitrot some more if not removed. With bpf_program__insns() API, which gives access to post-processed BPF program instructions of any given entry-point BPF program, it's now possible to do whatever necessary adjustments were possible with set_prep() API before, but also more. Given any such use case is automatically an advanced use case, requiring users to stick to low-level bpf_prog_load() APIs and managing their own prog FDs is reasonable. [0] Closes: https://github.com/libbpf/libbpf/issues/299 [1] Closes: https://github.com/libbpf/libbpf/issues/300 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211025224531.1088894-4-andrii@kernel.org
2021-10-25libbpf: Add ability to fetch bpf_program's underlying instructionsAndrii Nakryiko1-2/+34
Add APIs providing read-only access to bpf_program BPF instructions ([0]). This is useful for diagnostics purposes, but it also allows a cleaner support for cloning BPF programs after libbpf did all the FD resolution and CO-RE relocations, subprog instructions appending, etc. Currently, cloning BPF program is possible only through hijacking a half-broken bpf_program__set_prep() API, which doesn't really work well for anything but most primitive programs. For instance, set_prep() API doesn't allow adjusting BPF program load parameters which are necessary for loading fentry/fexit BPF programs (the case where BPF program cloning is a necessity if doing some sort of mass-attachment functionality). Given bpf_program__set_prep() API is set to be deprecated, having a cleaner alternative is a must. libbpf internally already keeps track of linear array of struct bpf_insn, so it's not hard to expose it. The only gotcha is that libbpf previously freed instructions array during bpf_object load time, which would make this API much less useful overall, because in between bpf_object__open() and bpf_object__load() a lot of changes to instructions are done by libbpf. So this patch makes libbpf hold onto prog->insns array even after BPF program loading. I think this is a small price for added functionality and improved introspection of BPF program code. See retsnoop PR ([1]) for how it can be used in practice and code savings compared to relying on bpf_program__set_prep(). [0] Closes: https://github.com/libbpf/libbpf/issues/298 [1] https://github.com/anakryiko/retsnoop/pull/1 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211025224531.1088894-3-andrii@kernel.org
2021-10-06libbpf: Deprecate bpf_{map,program}__{prev,next} APIs since v0.7Hengqi Chen1-12/+23
Deprecate bpf_{map,program}__{prev,next} APIs. Replace them with a new set of APIs named bpf_object__{prev,next}_{program,map} which follow the libbpf API naming convention ([0]). No functionality changes. [0] Closes: https://github.com/libbpf/libbpf/issues/296 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211003165844.4054931-2-hengqi.chen@gmail.com
2021-10-06libbpf: Deprecate bpf_object__unload() API since v0.6Hengqi Chen1-0/+1
BPF objects are not reloadable after unload. Users are expected to use bpf_object__close() to unload and free up resources in one operation. No need to expose bpf_object__unload() as a public API, deprecate it ([0]). Add bpf_object__unload() as an alias to internal bpf_object_unload() and replace all bpf_object__unload() uses to avoid compilation errors. [0] Closes: https://github.com/libbpf/libbpf/issues/290 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211002161000.3854559-1-hengqi.chen@gmail.com
2021-09-21libbpf: Refactor and simplify legacy kprobe codeAndrii Nakryiko1-1/+1
Refactor legacy kprobe handling code to follow the same logic as uprobe legacy logic added in the next patchs: - add append_to_file() helper that makes it simpler to work with tracefs file-based interface for creating and deleting probes; - move out probe/event name generation outside of the code that adds/removes it, which simplifies bookkeeping significantly; - change the probe name format to start with "libbpf_" prefix and include offset within kernel function; - switch 'unsigned long' to 'size_t' for specifying kprobe offsets, which is consistent with how uprobes define that, simplifies printf()-ing internally, and also avoids unnecessary complications on architectures where sizeof(long) != sizeof(void *). This patch also implicitly fixes the problem with invalid open() error handling present in poke_kprobe_events(), which (the function) this patch removes. Fixes: ca304b40c20d ("libbpf: Introduce legacy kprobe events support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210921210036.1545557-4-andrii@kernel.org
2021-09-20libbpf: Add doc comments in libbpf.hGrant Seltzer1-8/+57
This adds comments above functions in libbpf.h which document their uses. These comments are of a format that doxygen and sphinx can pick up and render. These are rendered by libbpf.readthedocs.org These doc comments are for: - bpf_object__find_map_by_name() - bpf_map__fd() - bpf_map__is_internal() - libbpf_get_error() - libbpf_num_possible_cpus() Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210918031457.36204-1-grantseltzer@gmail.com
2021-09-17libbpf: Constify all high-level program attach APIsAndrii Nakryiko1-18/+18
Attach APIs shouldn't need to modify bpf_program/bpf_map structs, so change all struct bpf_program and struct bpf_map pointers to const pointers. This is completely backwards compatible with no functional change. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210916015836.1248906-8-andrii@kernel.org
2021-09-17libbpf: Schedule open_opts.attach_prog_fd deprecation since v0.7Andrii Nakryiko1-0/+2
bpf_object_open_opts.attach_prog_fd makes a pretty strong assumption that bpf_object contains either only single freplace BPF program or all of BPF programs in BPF object are freplaces intended to replace different subprograms of the same target BPF program. This seems both a bit confusing, too assuming, and limiting. We've had bpf_program__set_attach_target() API which allows more fine-grained control over this, on a per-program level. As such, mark open_opts.attach_prog_fd as deprecated starting from v0.7, so that we have one more universal way of setting freplace targets. With previous change to allow NULL attach_func_name argument, and especially combined with BPF skeleton, arguable bpf_program__set_attach_target() is a more convenient and explicit API as well. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210916015836.1248906-7-andrii@kernel.org
2021-09-17libbpf: Deprecated bpf_object_open_opts.relaxed_core_relocsAndrii Nakryiko1-0/+1
It's relevant and hasn't been doing anything for a long while now. Deprecated it. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210916015836.1248906-4-andrii@kernel.org
2021-09-07libbpf: Change bpf_object_skeleton data field to const pointerMatt Smith1-1/+1
This change was necessary to enforce the implied contract that bpf_object_skeleton->data should not be mutated. The data will be cast to `void *` during assignment to handle the case where a user is compiling with older libbpf headers to avoid a compiler warning of `const void *` data being cast to `void *` Signed-off-by: Matt Smith <alastorze@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210901194439.3853238-2-alastorze@fb.com
2021-08-17libbpf: Add uprobe ref counter offset support for USDT semaphoresAndrii Nakryiko1-0/+4
When attaching to uprobes through perf subsystem, it's possible to specify offset of a so-called USDT semaphore, which is just a reference counted u16, used by kernel to keep track of how many tracers are attached to a given location. Support for this feature was added in [0], so just wire this through uprobe_opts. This is important to enable implementing USDT attachment and tracing through libbpf's bpf_program__attach_uprobe_opts() API. [0] a6ca88b241d5 ("trace_uprobe: support reference counter in fd-based uprobe") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210815070609.987780-16-andrii@kernel.org
2021-08-17libbpf: Add bpf_cookie to perf_event, kprobe, uprobe, and tp attach APIsAndrii Nakryiko1-12/+59
Wire through bpf_cookie for all attach APIs that use perf_event_open under the hood: - for kprobes, extend existing bpf_kprobe_opts with bpf_cookie field; - for perf_event, uprobe, and tracepoint APIs, add their _opts variants and pass bpf_cookie through opts. For kernel that don't support BPF_LINK_CREATE for perf_events, and thus bpf_cookie is not supported either, return error and log warning for user. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210815070609.987780-12-andrii@kernel.org
2021-07-23libbpf: Add bpf_map__pin_path functionEvgeniy Litvinenko1-0/+1
Add bpf_map__pin_path, so that the inconsistently named bpf_map__get_pin_path can be deprecated later. This is part of the effort towards libbpf v1.0: https://github.com/libbpf/libbpf/issues/307 Also, add a selftest for the new function. Signed-off-by: Evgeniy Litvinenko <evgeniyl@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210723221511.803683-1-evgeniyl@fb.com
2021-07-22libbpf: Export bpf_program__attach_kprobe_opts functionJiri Olsa1-0/+15
Export bpf_program__attach_kprobe_opts as a public API. Rename bpf_program_attach_kprobe_opts to bpf_kprobe_opts and turn it into OPTS struct. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Tested-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20210721215810.889975-4-jolsa@kernel.org
2021-07-16libbpf: Introduce 'btf_custom_path' to 'bpf_obj_open_opts'Shuyi Cheng1-1/+8
btf_custom_path allows developers to load custom BTF which libbpf will subsequently use for CO-RE relocation instead of vmlinux BTF. Having btf_custom_path in bpf_object_open_opts one can directly use the skeleton's <objname>_bpf__open_opts() API to pass in the btf_custom_path parameter, as opposed to using bpf_object__load_xattr() which is slated to be deprecated ([0]). This work continues previous work started by another developer ([1]). [0] https://lore.kernel.org/bpf/CAEf4BzbJZLjNoiK8_VfeVg_Vrg=9iYFv+po-38SMe=UzwDKJ=Q@mail.gmail.com/#t [1] https://yhbt.net/lore/all/CAEf4Bzbgw49w2PtowsrzKQNcxD4fZRE6AKByX-5-dMo-+oWHHA@mail.gmail.com/ Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1626180159-112996-2-git-send-email-chengshuyi@linux.alibaba.com
generated by cgit v1.2.3 (git 2.39.1) at 2025-02-05 23:16:35 +0000