bpf_program__title() is deprecated, switch to bpf_program__section_name() and
avoid compilation warnings.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-9-andriin@fb.com

The system for "Auto-detecting system features" located under
tools/build/ are (currently) used by perf, libbpf and bpftool. It can
contain stalled feature detection files, which are not cleaned up by
libbpf and bpftool on make clean (side-note: perf tool is correct).

Fix this by making the users invoke the make clean target.

Some details about the changes. The libbpf Makefile already had a
clean-config target (which seems to be copy-pasted from perf), but this
target was not "connected" (a make dependency) to clean target. Choose
not to rename target as someone might be using it. Did change the output
from "CLEAN config" to "CLEAN feature-detect", to make it more clear
what happens.

This is related to the complaint and troubleshooting in the following
link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/
Link: https://lore.kernel.org/bpf/159851841661.1072907.13770213104521805592.stgit@firesoul

The set symbol does not have the unique number suffix,
so we need to give it a special parsing function.

This was omitted in the first batch, because there was
no set support yet, so it slipped in the testing.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-3-jolsa@kernel.org

To make sure we don't crash on malformed symbols.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-2-jolsa@kernel.org

Similar to bpf_local_storage for sockets, add local storage for inodes.
The life-cycle of storage is managed with the life-cycle of the inode.
i.e. the storage is destroyed along with the owning inode.

The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the
security blob which are now stackable and can co-exist with other LSMs.
Signed-off-by: NKP Singh <kpsingh@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-6-kpsingh@chromium.org

The link query for bpf iterators is implemented.
Besides being shown to the user what bpf iterator
the link represents, the target_name is also used
to filter out what additional information should be
printed out, e.g., whether map_id should be shown or not.
The following is an example of bpf_iter link dump,
plain output or pretty output.

  $ bpftool link show
  11: iter  prog 59  target_name task
          pids test_progs(1749)
  34: iter  prog 173  target_name bpf_map_elem  map_id 127
          pids test_progs_1(1753)
  $ bpftool -p link show
  [{
          "id": 11,
          "type": "iter",
          "prog_id": 59,
          "target_name": "task",
          "pids": [{
                  "pid": 1749,
                  "comm": "test_progs"
              }
          ]
      },{
          "id": 34,
          "type": "iter",
          "prog_id": 173,
          "target_name": "bpf_map_elem",
          "map_id": 127,
          "pids": [{
                  "pid": 1753,
                  "comm": "test_progs_1"
              }
          ]
      }
  ]
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200821184420.574430-1-yhs@fb.com

The data of compressed section should be aligned to 4
(for 32bit) or 8 (for 64 bit) bytes.

The binutils ld sets sh_addralign to 1, which makes libelf
fail with misaligned section error during the update as
reported by Jesper:

   FAILED elf_update(WRITE): invalid section alignment

While waiting for ld fix, we can fix compressed sections
sh_addralign value manually.

Adding warning in -vv mode when the fix is triggered:

  $ ./tools/bpf/resolve_btfids/resolve_btfids -vv vmlinux
  ...
  section(36) .comment, size 44, link 0, flags 30, type=1
  section(37) .debug_aranges, size 45684, link 0, flags 800, type=1
   - fixing wrong alignment sh_addralign 16, expected 8
  section(38) .debug_info, size 129104957, link 0, flags 800, type=1
   - fixing wrong alignment sh_addralign 1, expected 8
  section(39) .debug_abbrev, size 1152583, link 0, flags 800, type=1
   - fixing wrong alignment sh_addralign 1, expected 8
  section(40) .debug_line, size 7374522, link 0, flags 800, type=1
   - fixing wrong alignment sh_addralign 1, expected 8
  section(41) .debug_frame, size 702463, link 0, flags 800, type=1
  section(42) .debug_str, size 1017571, link 0, flags 830, type=1
   - fixing wrong alignment sh_addralign 1, expected 8
  section(43) .debug_loc, size 3019453, link 0, flags 800, type=1
   - fixing wrong alignment sh_addralign 1, expected 8
  section(44) .debug_ranges, size 1744583, link 0, flags 800, type=1
   - fixing wrong alignment sh_addralign 16, expected 8
  section(45) .symtab, size 2955888, link 46, flags 0, type=2
  section(46) .strtab, size 2613072, link 0, flags 0, type=3
  ...
  update ok for vmlinux

Another workaround is to disable compressed debug info data
CONFIG_DEBUG_INFO_COMPRESSED kernel option.

Fixes: fbbb68de ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Reported-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NYonghong Song <yhs@fb.com>
Cc: Mark Wielaard <mjw@redhat.com>
Cc: Nick Clifton <nickc@redhat.com>
Link: https://lore.kernel.org/bpf/20200819092342.259004-1-jolsa@kernel.org

Most netlink-related functions were unique to bpftool usage, so I moved them
into net.c. Few functions are still used by both bpftool and libbpf itself
internally, so I've copy-pasted them (libbpf_nl_get_link,
libbpf_netlink_open). It's a bit of duplication of code, but better separation
of libbpf as a library with public API and bpftool, relying on unexposed
functions in libbpf.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200819013607.3607269-3-andriin@fb.com

When the error code is EAGAIN, the kernel signals the user
space should retry the read() operation for bpf iterators.
Let us do it.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200818222312.2181675-1-yhs@fb.com

The comment in the code describes this in good details. Generate such a memory
layout that would work both on 32-bit and 64-bit architectures for user-space.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-9-andriin@fb.com

Fix few compilation warnings in bpftool when compiling in 32-bit mode.
Abstract away u64 to pointer conversion into a helper function.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-2-andriin@fb.com

Seems like C++17 standard mode doesn't recognize typeof() anymore. This can
be tested by compiling test_cpp test with -std=c++17 or -std=c++1z options.
The use of typeof in skeleton generated code is unnecessary, all types are
well-known at the time of code generation, so remove all typeof()'s to make
skeleton code more future-proof when interacting with C++ compilers.

Fixes: 985ead41 ("bpftool: Add skeleton codegen command")
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200812025907.1371956-1-andriin@fb.com

int sets_patch(struct object *obj) doesn't have a 'return 0' at the end.

Fixes: fbbb68de ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200806155225.637202-1-sdf@google.com

Previous commit adjusted kernel uapi for map
element bpf iterator. This patch adjusted libbpf API
due to uapi change. bpftool and bpf_iter selftests
are also changed accordingly.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200805055058.1457623-1-yhs@fb.com

Instead of re-implementing generic BTF parsing logic, use libbpf's API.
Also add .gitignore for resolve_btfids's build artifacts.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200802013219.864880-4-andriin@fb.com

Use generic libbpf API to parse BTF data from file, instead of re-implementing
it in bpftool.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200802013219.864880-3-andriin@fb.com

In case of btf_id does not exist, a negative error code -ENOENT
should be returned.

Fixes: c93cc690 ("bpftool: add ability to dump BTF types")
Signed-off-by: NTianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NTobias Klauser <tklauser@distanz.ch>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200802111540.5384-1-tianjia.zhang@linux.alibaba.com

Add info on link detach sub-command to man page. Add detach to bash-completion
as well.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NSong Liu <songliubraving@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com.
Link: https://lore.kernel.org/bpf/20200731182830.286260-6-andriin@fb.com

Add ability to force-detach BPF link. Also add missing error message, if
specified link ID is wrong.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NSong Liu <songliubraving@fb.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200731182830.286260-5-andriin@fb.com

Assign "lsm" as a printed name for BPF_PROG_TYPE_LSM in bpftool, so that
it can use it when listing programs loaded on the system or when probing
features.
Signed-off-by: NQuentin Monnet <quentin@isovalent.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200724090618.16378-3-quentin@isovalent.com

For probing program and map types, bpftool loops on type values and uses
the relevant type name in prog_type_name[] or map_type_name[]. To ensure
the name exists, we exit from the loop if we go over the size of the
array.

However, this is not enough in the case where the arrays have "holes" in
them, program or map types for which they have no name, but not at the
end of the list. This is currently the case for BPF_PROG_TYPE_LSM, not
known to bpftool and which name is a null string. When probing for
features, bpftool attempts to strlen() that name and segfaults.

Let's fix it by skipping probes for "unknown" program and map types,
with an informational message giving the numeral value in that case.

Fixes: 93a3545d ("tools/bpftool: Add name mappings for SK_LOOKUP prog and attach type")
Reported-by: NPaul Chaignon <paul@cilium.io>
Signed-off-by: NQuentin Monnet <quentin@isovalent.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200724090618.16378-2-quentin@isovalent.com

The optional parameter "map MAP" can be added to "bpftool iter"
command to create a bpf iterator for map elements. For example,
  bpftool iter pin ./prog.o /sys/fs/bpf/p1 map id 333

For map element bpf iterator "map MAP" parameter is required.
Otherwise, bpf link creation will return an error.

Quentin Monnet kindly provided bash-completion implementation
for new "map MAP" option.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184119.590799-1-yhs@fb.com

Strip away DWARF info from .bpf.o files, before generating BPF skeletons.
This reduces bpftool binary size from 3.43MB to 2.58MB.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200722043804.2373298-1-andriin@fb.com

The bpftool sources include code to walk file trees, but use multiple
frameworks to do so: nftw and fts. While nftw conforms to POSIX/SUSv3 and
is widely available, fts is not conformant and less common, especially on
non-glibc systems. The inconsistent framework usage hampers maintenance
and portability of bpftool, in particular for embedded systems.

Standardize code usage by rewriting one fts-based function to use nftw and
clean up some related function warnings by extending use of "const char *"
arguments. This change helps in building bpftool against musl for OpenWrt.

Also fix an unsafe call to dirname() by duplicating the string to pass,
since some implementations may directly alter it. The same approach is
used in libbpf.c.
Signed-off-by: NTony Ambardar <Tony.Ambardar@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200721024817.13701-1-Tony.Ambardar@gmail.com

A handful of samples and selftests fail to build on s390, because
after commit 0ebeea8c ("bpf: Restrict bpf_probe_read{, str}()
only to archs where they work") bpf_probe_read is not available
anymore.

Fix by using bpf_probe_read_kernel.
Signed-off-by: NIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720114806.88823-1-iii@linux.ibm.com

Fix pass 0 to PTR_ERR, also dump more err info using
libbpf_strerror.

Fixes: 5dc7a8b2 ("bpftool, selftests/bpf: Embed object file inside skeleton")
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200717123059.29624-1-yuehaibing@huawei.com

Pulling header files directly out of the kernel sources for inclusion in
userspace programs is highly error prone, not least because it bypasses
the kbuild infrastructure entirely and so may end up referencing other
header files that have not been generated.

Subsequent patches will cause compiler.h to pull in the ungenerated
asm/rwonce.h file via filter.h, breaking the build for tools/bpf:

  | $ make -C tools/bpf
  | make: Entering directory '/linux/tools/bpf'
  |   CC       bpf_jit_disasm.o
  |   LINK     bpf_jit_disasm
  |   CC       bpf_dbg.o
  | In file included from /linux/include/uapi/linux/filter.h:9,
  |                  from /linux/tools/bpf/bpf_dbg.c:41:
  | /linux/include/linux/compiler.h:247:10: fatal error: asm/rwonce.h: No such file or directory
  |  #include <asm/rwonce.h>
  |           ^~~~~~~~~~~~~~
  | compilation terminated.
  | make: *** [Makefile:61: bpf_dbg.o] Error 1
  | make: Leaving directory '/linux/tools/bpf'

Take a copy of the installed version of linux/filter.h  (i.e. the one
created by the 'headers_install' target) into tools/include/uapi/linux/
and adjust the BPF tool Makefile to reference the local include
directories instead of those in the main source tree.

Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Suggested-by: NDaniel Borkmann <daniel@iogearbox.net>
Reported-by: NXiao Yang <ice_yangxiao@163.com>
Signed-off-by: NWill Deacon <will@kernel.org>

Make bpftool show human-friendly identifiers for newly introduced program
and attach type, BPF_PROG_TYPE_SK_LOOKUP and BPF_SK_LOOKUP, respectively.

Also, add the new prog type bash-completion, man page and help message.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200717103536.397595-14-jakub@cloudflare.com

Stephen and 0-DAY CI Kernel Test Service reported broken cross build
for arm (arm-linux-gnueabi-gcc (GCC) 9.3.0), with following output:

   /tmp/ccMS5uth.s: Assembler messages:
   /tmp/ccMS5uth.s:69: Error: unrecognized symbol type ""
   /tmp/ccMS5uth.s:82: Error: unrecognized symbol type ""

Having '@object' for .type  diretive is  wrong because '@' is comment
character for some architectures. Using STT_OBJECT instead that should
work everywhere.

Also using HOST* variables to build resolve_btfids so it's properly
build in crossbuilds (stolen from objtool's Makefile).
Reported-by: Nkernel test robot <lkp@intel.com>
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/bpf/20200714102534.299280-2-jolsa@kernel.org

Reliably remove all the type modifiers from read-only (.rodata) global
variable definitions, including cases of inner field const modifiers and
arrays of const values.

Also modify one of selftests to ensure that const volatile struct doesn't
prevent user-space from modifying .rodata variable.

Fixes: 985ead41 ("bpftool: Add skeleton codegen command")
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200713232409.3062144-3-andriin@fb.com

Don't emit warning that bpftool was built without PID iterator support. This
error garbles JSON output of otherwise perfectly valid show commands.
Reported-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200710232605.20918-1-andriin@fb.com

The resolve_btfids tool will be used during the vmlinux linking,
so it's necessary it's ready for it.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Tested-by: NAndrii Nakryiko <andriin@fb.com>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-3-jolsa@kernel.org

The resolve_btfids tool scans elf object for .BTF_ids section
and resolves its symbols with BTF ID values.

It will be used to during linking time to resolve arrays of BTF
ID values used in verifier, so these IDs do not need to be
resolved in runtime.

The expected layout of .BTF_ids section is described in main.c
header. Related kernel changes are coming in following changes.

Build issue reported by 0-DAY CI Kernel Test Service.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200711215329.41165-2-jolsa@kernel.org

emit_obj_refs_json needs to added the same as with emit_obj_refs_plain
to prevent segfaults, similar to Commit "8ae4121b bpf: Fix bpftool
without skeleton code enabled"). See the error below:

    # ./bpftool -p prog
    {
        "error": "bpftool built without PID iterator support"
    },[{
            "id": 2,
            "type": "cgroup_skb",
            "tag": "7be49e3934a125ba",
            "gpl_compatible": true,
            "loaded_at": 1594052789,
            "uid": 0,
            "bytes_xlated": 296,
            "jited": true,
            "bytes_jited": 203,
            "bytes_memlock": 4096,
            "map_ids": [2,3
    Segmentation fault (core dumped)

The same happens for ./bpftool -p map, as well as ./bpftool -j prog/map.

Fixes: d53dee3f ("tools/bpftool: Show info for processes holding BPF map/prog/link/btf FDs")
Signed-off-by: NLouis Peens <louis.peens@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NSimon Horman <simon.horman@netronome.com>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200708110827.7673-1-louis.peens@netronome.com

Support attaching to BPF_CGROUP_INET_SOCK_RELEASE and properly
display attach type upon prog dump.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200706230128.4073544-4-sdf@google.com

Fix segfault from bpftool by adding emit_obj_refs_plain when skeleton
code is disabled.

Tested by deleting BUILD_BPF_SKELS in Makefile. We found this doing
backports for Cilium when a testing image pulled in latest bpf-next
bpftool, but kept using an older clang-7.

  # ./bpftool prog show
  Error: bpftool built without PID iterator support
  3: cgroup_skb  tag 7be49e3934a125ba  gpl
          loaded_at 2020-07-01T08:01:29-0700  uid 0
  Segmentation fault

Fixes: d53dee3f ("tools/bpftool: Show info for processes holding BPF map/prog/link/btf FDs")
Reported-by: NJoe Stringer <joe@wand.net.nz>
Signed-off-by: NJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/159375071997.14984.17404504293832961401.stgit@john-XPS-13-9370

Turn off -Wnested-externs to avoid annoying warnings in BUILD_BUG_ON macro when
compiling bpftool:

In file included from /data/users/andriin/linux/tools/include/linux/build_bug.h:5,
                 from /data/users/andriin/linux/tools/include/linux/kernel.h:8,
                 from /data/users/andriin/linux/kernel/bpf/disasm.h:10,
                 from /data/users/andriin/linux/kernel/bpf/disasm.c:8:
/data/users/andriin/linux/kernel/bpf/disasm.c: In function ‘__func_get_name’:
/data/users/andriin/linux/tools/include/linux/compiler.h:37:38: warning: nested extern declaration of ‘__compiletime_assert_0’ [-Wnested-externs]
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
                                      ^~~~~~~~~~~~~~~~~~~~~
/data/users/andriin/linux/tools/include/linux/compiler.h:16:15: note: in definition of macro ‘__compiletime_assert’
   extern void prefix ## suffix(void) __compiletime_error(msg); \
               ^~~~~~
/data/users/andriin/linux/tools/include/linux/compiler.h:37:2: note: in expansion of macro ‘_compiletime_assert’
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
  ^~~~~~~~~~~~~~~~~~~
/data/users/andriin/linux/tools/include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                     ^~~~~~~~~~~~~~~~~~
/data/users/andriin/linux/tools/include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
  ^~~~~~~~~~~~~~~~
/data/users/andriin/linux/kernel/bpf/disasm.c:20:2: note: in expansion of macro ‘BUILD_BUG_ON’
  BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
  ^~~~~~~~~~~~
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200701212816.2072340-1-andriin@fb.com

In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h,
generated from available kernel, doesn't contain all the types necessary for
BPF program compilation. For such set up, the most maintainable way to deal
with this problem is to keep pre-generated (almost up-to-date) vmlinux.h
checked in and use it for compilation purposes. bpftool after that can deal
with kernel missing some of the features in runtime with no problems.

To that effect, allow to specify path to custom vmlinux.h to bpftool's
Makefile with VMLINUX_H variable.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200630004759.521530-1-andriin@fb.com

Define attach_type_name in common.c instead of main.h so it is only
defined once. This leads to a slight decrease in the binary size of
bpftool.

Before:

   text	   data	    bss	    dec	    hex	filename
 399024	  11168	1573160	1983352	 1e4378	bpftool

After:

   text	   data	    bss	    dec	    hex	filename
 398256	  10880	1573160	1982296	 1e3f58	bpftool
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200624143154.13145-1-tklauser@distanz.ch

Define prog_type_name in prog.c instead of main.h so it is only defined
once. This leads to a slight decrease in the binary size of bpftool.

Before:

   text	   data	    bss	    dec	    hex	filename
 401032	  11936	1573160	1986128	 1e4e50	bpftool

After:

   text	   data	    bss	    dec	    hex	filename
 399024	  11168	1573160	1983352	 1e4378	bpftool
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200624143124.12914-1-tklauser@distanz.ch