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2021-05-26libbpf: Streamline error reporting for high-level APIsAndrii Nakryiko1-3/+4
Implement changes to error reporting for high-level libbpf APIs to make them less surprising and less error-prone to users: - in all the cases when error happens, errno is set to an appropriate error value; - in libbpf 1.0 mode, all pointer-returning APIs return NULL on error and error code is communicated through errno; this applies both to APIs that already returned NULL before (so now they communicate more detailed error codes), as well as for many APIs that used ERR_PTR() macro and encoded error numbers as fake pointers. - in legacy (default) mode, those APIs that were returning ERR_PTR(err), continue doing so, but still set errno. With these changes, errno can be always used to extract actual error, regardless of legacy or libbpf 1.0 modes. This is utilized internally in libbpf in places where libbpf uses it's own high-level APIs. libbpf_get_error() is adapted to handle both cases completely transparently to end-users (and is used by libbpf consistently as well). More context, justification, and discussion can be found in "Libbpf: the road to v1.0" document ([0]). [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210525035935.1461796-5-andrii@kernel.org
2020-01-10libbpf: Poison kernel-only integer typesAndrii Nakryiko1-0/+3
It's been a recurring issue with types like u32 slipping into libbpf source code accidentally. This is not detected during builds inside kernel source tree, but becomes a compilation error in libbpf's Github repo. Libbpf is supposed to use only __{s,u}{8,16,32,64} typedefs, so poison {s,u}{8,16,32,64} explicitly in every .c file. Doing that in a bit more centralized way, e.g., inside libbpf_internal.h breaks selftests, which are both using kernel u32 and libbpf_internal.h. This patch also fixes a new u32 occurence in libbpf.c, added recently. Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200110181916.271446-1-andriin@fb.com
2018-11-30tools/bpf: make libbpf _GNU_SOURCE friendlyYonghong Song1-0/+1
During porting libbpf to bcc, I got some warnings like below: ... [ 2%] Building C object src/cc/CMakeFiles/bpf-shared.dir/libbpf/src/libbpf.c.o /home/yhs/work/bcc2/src/cc/libbpf/src/libbpf.c:12:0: warning: "_GNU_SOURCE" redefined [enabled by default] #define _GNU_SOURCE ... [ 3%] Building C object src/cc/CMakeFiles/bpf-shared.dir/libbpf/src/libbpf_errno.c.o /home/yhs/work/bcc2/src/cc/libbpf/src/libbpf_errno.c: In function ‘libbpf_strerror’: /home/yhs/work/bcc2/src/cc/libbpf/src/libbpf_errno.c:45:7: warning: assignment makes integer from pointer without a cast [enabled by default] ret = strerror_r(err, buf, size); ... bcc is built with _GNU_SOURCE defined and this caused the above warning. This patch intends to make libpf _GNU_SOURCE friendly by . define _GNU_SOURCE in libbpf.c unless it is not defined . undefine _GNU_SOURCE as non-gnu version of strerror_r is expected. Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-08libbpf: relicense libbpf as LGPL-2.1 OR BSD-2-ClauseAlexei Starovoitov1-14/+1
libbpf is maturing as a library and gaining features that no other bpf libraries support (BPF Type Format, bpf to bpf calls, etc) Many Apache2 licensed projects (like bcc, bpftrace, gobpf, cilium, etc) would like to use libbpf, but cannot do this yet, since Apache Foundation explicitly states that LGPL is incompatible with Apache2. Hence let's relicense libbpf as dual license LGPL-2.1 or BSD-2-Clause, since BSD-2 is compatible with Apache2. Dual LGPL or Apache2 is invalid combination. Fix license mistake in Makefile as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrey Ignatov <rdna@fb.com> Acked-by: Arnaldo Carvalho de Melo <acme@kernel.org> Acked-by: Björn Töpel <bjorn.topel@intel.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Beckett <david.beckett@netronome.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Quentin Monnet <quentin.monnet@netronome.com> Acked-by: Thomas Graf <tgraf@suug.ch> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Wang Nan <wangnan0@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-09-07tools/bpf: add more netlink functionalities in lib/bpfYonghong Song1-0/+1
This patch added a few netlink attribute parsing functions and the netlink API functions to query networking links, tc classes, tc qdiscs and tc filters. For example, the following API is to get networking links: int nl_get_link(int sock, unsigned int nl_pid, dump_nlmsg_t dump_link_nlmsg, void *cookie); Note that when the API is called, the user also provided a callback function with the following signature: int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb); The "cookie" is the parameter the user passed to the API and will be available for the callback function. The "msg" is the information about the result, e.g., ifinfomsg or tcmsg. The "tb" is the parsed netlink attributes. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-07-11tools: libbpf: move library error code into a separate fileJakub Kicinski1-0/+74
libbpf_strerror() depends on XSI-compliant (POSIX) version of strerror_r(), which prevents us from using GNU-extensions in libbpf.c, like reallocarray() or dup3(). Move error printing code into a separate file to allow it to continue using POSIX strerror_r(). No functional changes. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>