Fix bpftool to include libbpf header files with the bpf/ prefix, to be
consistent with external users of the library. Also ensure that all
includes of exported libbpf header files (those that are exported on 'make
install' of the library) use bracketed includes instead of quoted.
To make sure no new files are introduced that doesn't include the bpf/
prefix in its include, remove tools/lib/bpf from the include path entirely,
and use tools/lib instead.
Fixes: 6910d7d386 ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560684.1683545.4765181397974997027.stgit@toke.dk
When auto-generated BPF skeleton C code is included from C++ application, it
triggers compilation error due to void * being implicitly casted to whatever
target pointer type. This is supported by C, but not C++. To solve this
problem, add explicit casts, where necessary.
To ensure issues like this are captured going forward, add skeleton usage in
test_cpp test.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191226210253.3132060-1-andriin@fb.com
Change format string referring to just single argument out of two available.
Some versions of libc can reject such format string.
Reported-by: Nikita Shirokov <tehnerd@tehnerd.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191218214314.2403729-1-andriin@fb.com
Embed contents of BPF object file used for BPF skeleton generation inside
skeleton itself. This allows to keep BPF object file and its skeleton in sync
at all times, and simpifies skeleton instantiation.
Also switch existing selftests to not require BPF_EMBED_OBJ anymore.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191218052552.2915188-2-andriin@fb.com
The ident variable has already been declared at the top of the function
and doesn't need to be re-declared.
Fixes: 985ead416d ("bpftool: Add skeleton codegen command")
Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191216112733.GA28366@Omicron
Add support for generation of mmap()-ed read-only view of libbpf-provided
extern variables. As externs are not supposed to be provided by user code
(that's what .data, .bss, and .rodata is for), don't mmap() it initially. Only
after skeleton load is performed, map .extern contents as read-only memory.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014710.3449601-4-andriin@fb.com
Add `bpftool gen skeleton` command, which takes in compiled BPF .o object file
and dumps a BPF skeleton struct and related code to work with that skeleton.
Skeleton itself is tailored to a specific structure of provided BPF object
file, containing accessors (just plain struct fields) for every map and
program, as well as dedicated space for bpf_links. If BPF program is using
global variables, corresponding structure definitions of compatible memory
layout are emitted as well, making it possible to initialize and subsequently
read/update global variables values using simple and clear C syntax for
accessing fields. This skeleton majorly improves usability of
opening/loading/attaching of BPF object, as well as interacting with it
throughout the lifetime of loaded BPF object.
Generated skeleton struct has the following structure:
struct <object-name> {
/* used by libbpf's skeleton API */
struct bpf_object_skeleton *skeleton;
/* bpf_object for libbpf APIs */
struct bpf_object *obj;
struct {
/* for every defined map in BPF object: */
struct bpf_map *<map-name>;
} maps;
struct {
/* for every program in BPF object: */
struct bpf_program *<program-name>;
} progs;
struct {
/* for every program in BPF object: */
struct bpf_link *<program-name>;
} links;
/* for every present global data section: */
struct <object-name>__<one of bss, data, or rodata> {
/* memory layout of corresponding data section,
* with every defined variable represented as a struct field
* with exactly the same type, but without const/volatile
* modifiers, e.g.:
*/
int *my_var_1;
...
} *<one of bss, data, or rodata>;
};
This provides great usability improvements:
- no need to look up maps and programs by name, instead just
my_obj->maps.my_map or my_obj->progs.my_prog would give necessary
bpf_map/bpf_program pointers, which user can pass to existing libbpf APIs;
- pre-defined places for bpf_links, which will be automatically populated for
program types that libbpf knows how to attach automatically (currently
tracepoints, kprobe/kretprobe, raw tracepoint and tracing programs). On
tearing down skeleton, all active bpf_links will be destroyed (meaning BPF
programs will be detached, if they are attached). For cases in which libbpf
doesn't know how to auto-attach BPF program, user can manually create link
after loading skeleton and they will be auto-detached on skeleton
destruction:
my_obj->links.my_fancy_prog = bpf_program__attach_cgroup_whatever(
my_obj->progs.my_fancy_prog, <whatever extra param);
- it's extremely easy and convenient to work with global data from userspace
now. Both for read-only and read/write variables, it's possible to
pre-initialize them before skeleton is loaded:
skel = my_obj__open(raw_embed_data);
my_obj->rodata->my_var = 123;
my_obj__load(skel); /* 123 will be initialization value for my_var */
After load, if kernel supports mmap() for BPF arrays, user can still read
(and write for .bss and .data) variables values, but at that point it will
be directly mmap()-ed to BPF array, backing global variables. This allows to
seamlessly exchange data with BPF side. From userspace program's POV, all
the pointers and memory contents stay the same, but mapped kernel memory
changes to point to created map.
If kernel doesn't yet support mmap() for BPF arrays, it's still possible to
use those data section structs to pre-initialize .bss, .data, and .rodata,
but after load their pointers will be reset to NULL, allowing user code to
gracefully handle this condition, if necessary.
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/20191214014341.3442258-14-andriin@fb.com
Jagadeesh Pagadala