Commit Graph

386 Commits

Author SHA1 Message Date
Andrii Nakryiko 763ff0e7d9 libbpf: fix another GCC8 warning for strncpy
Similar issue was fixed in cdfc7f888c ("libbpf: fix GCC8 warning for
strncpy") already. This one was missed. Fixing now.

Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-16 10:34:31 -07:00
Andrii Nakryiko 36db2a94f1 libbpf: fix ptr to u64 conversion warning on 32-bit platforms
On 32-bit platforms compiler complains about conversion:

libbpf.c: In function ‘perf_event_open_probe’:
libbpf.c:4112:17: error: cast from pointer to integer of different
size [-Werror=pointer-to-int-cast]
  attr.config1 = (uint64_t)(void *)name; /* kprobe_func or uprobe_path */
                 ^

Reported-by: Matt Hart <matthew.hart@linaro.org>
Fixes: b265002747 ("libbpf: add kprobe/uprobe attach API")
Tested-by: Matt Hart <matthew.hart@linaro.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-12 14:51:03 +02:00
Andrii Nakryiko cd07a95f9b libbpf: add perf_buffer_ prefix to README
perf_buffer "object" is part of libbpf API now, add it to the list of
libbpf function prefixes.

Suggested-by: Daniel Borkman <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-08 15:35:43 +02:00
Andrii Nakryiko d7ff34d5fb libbpf: auto-set PERF_EVENT_ARRAY size to number of CPUs
For BPF_MAP_TYPE_PERF_EVENT_ARRAY typically correct size is number of
possible CPUs. This is impossible to specify at compilation time. This
change adds automatic setting of PERF_EVENT_ARRAY size to number of
system CPUs, unless non-zero size is specified explicitly. This allows
to adjust size for advanced specific cases, while providing convenient
and logical defaults.

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>
2019-07-08 15:35:43 +02:00
Andrii Nakryiko fb84b82246 libbpf: add perf buffer API
BPF_MAP_TYPE_PERF_EVENT_ARRAY map is often used to send data from BPF program
to user space for additional processing. libbpf already has very low-level API
to read single CPU perf buffer, bpf_perf_event_read_simple(), but it's hard to
use and requires a lot of code to set everything up. This patch adds
perf_buffer abstraction on top of it, abstracting setting up and polling
per-CPU logic into simple and convenient API, similar to what BCC provides.

perf_buffer__new() sets up per-CPU ring buffers and updates corresponding BPF
map entries. It accepts two user-provided callbacks: one for handling raw
samples and one for get notifications of lost samples due to buffer overflow.

perf_buffer__new_raw() is similar, but provides more control over how
perf events are set up (by accepting user-provided perf_event_attr), how
they are handled (perf_event_header pointer is passed directly to
user-provided callback), and on which CPUs ring buffers are created
(it's possible to provide a list of CPUs and corresponding map keys to
update). This API allows advanced users fuller control.

perf_buffer__poll() is used to fetch ring buffer data across all CPUs,
utilizing epoll instance.

perf_buffer__free() does corresponding clean up and unsets FDs from BPF map.

All APIs are not thread-safe. User should ensure proper locking/coordination if
used in multi-threaded set up.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-08 15:35:43 +02:00
Andrii Nakryiko ef99b02b23 libbpf: capture value in BTF type info for BTF-defined map defs
Change BTF-defined map definitions to capture compile-time integer
values as part of BTF type definition, to avoid split of key/value type
information and actual type/size/flags initialization for maps.

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>
2019-07-05 22:52:25 +02:00
Andrii Nakryiko 84bf5e1f4f libbpf: add raw tracepoint attach API
Add a wrapper utilizing bpf_link "infrastructure" to allow attaching BPF
programs to raw tracepoints.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-05 22:37:30 +02:00
Andrii Nakryiko f6de59c17f libbpf: add tracepoint attach API
Allow attaching BPF programs to kernel tracepoint BPF hooks specified by
category and name.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-05 22:37:30 +02:00
Andrii Nakryiko b265002747 libbpf: add kprobe/uprobe attach API
Add ability to attach to kernel and user probes and retprobes.
Implementation depends on perf event support for kprobes/uprobes.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-05 22:37:30 +02:00
Andrii Nakryiko 63f2f5ee85 libbpf: add ability to attach/detach BPF program to perf event
bpf_program__attach_perf_event allows to attach BPF program to existing
perf event hook, providing most generic and most low-level way to attach BPF
programs. It returns struct bpf_link, which should be passed to
bpf_link__destroy to detach and free resources, associated with a link.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-05 22:37:30 +02:00
Andrii Nakryiko 1c2e9efc26 libbpf: introduce concept of bpf_link
bpf_link is an abstraction of an association of a BPF program and one of
many possible BPF attachment points (hooks). This allows to have uniform
interface for detaching BPF programs regardless of the nature of link
and how it was created. Details of creation and setting up of a specific
bpf_link is handled by corresponding attachment methods
(bpf_program__attach_xxx) added in subsequent commits. Once successfully
created, bpf_link has to be eventually destroyed with
bpf_link__destroy(), at which point BPF program is disassociated from
a hook and all the relevant resources are freed.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-05 22:37:30 +02:00
Andrii Nakryiko d66f43666a libbpf: make libbpf_strerror_r agnostic to sign of error
It's often inconvenient to switch sign of error when passing it into
libbpf_strerror_r. It's better for it to handle that automatically.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-05 22:37:30 +02:00
Leo Yan 33bae185f7 bpf, libbpf, smatch: Fix potential NULL pointer dereference
Based on the following report from Smatch, fix the potential NULL
pointer dereference check:

  tools/lib/bpf/libbpf.c:3493
  bpf_prog_load_xattr() warn: variable dereferenced before check 'attr'
  (see line 3483)

  3479 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
  3480                         struct bpf_object **pobj, int *prog_fd)
  3481 {
  3482         struct bpf_object_open_attr open_attr = {
  3483                 .file           = attr->file,
  3484                 .prog_type      = attr->prog_type,
                                         ^^^^^^
  3485         };

At the head of function, it directly access 'attr' without checking
if it's NULL pointer. This patch moves the values assignment after
validating 'attr' and 'attr->file'.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-03 12:17:29 +02:00
Andrii Nakryiko cdfc7f888c libbpf: fix GCC8 warning for strncpy
GCC8 started emitting warning about using strncpy with number of bytes
exactly equal destination size, which is generally unsafe, as can lead
to non-zero terminated string being copied. Use IFNAMSIZ - 1 as number
of bytes to ensure name is always zero-terminated.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-03 11:52:45 +02:00
Stanislav Fomichev 4cdbfb59c4 libbpf: support sockopt hooks
Make libbpf aware of new sockopt hooks so it can derive prog type
and hook point from the section names.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-27 15:25:17 -07:00
Maxim Mikityanskiy 123e8da1d3 xsk: Change the default frame size to 4096 and allow controlling it
The typical XDP memory scheme is one packet per page. Change the AF_XDP
frame size in libbpf to 4096, which is the page size on x86, to allow
libbpf to be used with the drivers with the packet-per-page scheme.

Add a command line option -f to xdpsock to allow to specify a custom
frame size.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-27 22:53:26 +02:00
Maxim Mikityanskiy 2761ed4b6e libbpf: Support getsockopt XDP_OPTIONS
Query XDP_OPTIONS in libbpf to determine if the zero-copy mode is active
or not.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-27 22:53:26 +02:00
Ivan Khoronzhuk 950649791b libbpf: fix max() type mismatch for 32bit
It fixes build error for 32bit caused by type mismatch
size_t/unsigned long.

Fixes: bf82927125 ("libbpf: refactor map initialization")
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-26 14:41:20 +02:00
Colin Ian King 900de4ac49 libbpf: fix spelling mistake "conflictling" -> "conflicting"
There are several spelling mistakes in pr_warning messages. Fix these.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-24 18:18:30 -07:00
David S. Miller dca73a65a6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:

====================
pull-request: bpf-next 2019-06-19

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) new SO_REUSEPORT_DETACH_BPF setsocktopt, from Martin.

2) BTF based map definition, from Andrii.

3) support bpf_map_lookup_elem for xskmap, from Jonathan.

4) bounded loops and scalar precision logic in the verifier, from Alexei.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-20 00:06:27 -04:00
Andrii Nakryiko a324aae32f libbpf: constify getter APIs
Add const qualifiers to bpf_object/bpf_program/bpf_map arguments for
getter APIs. There is no need for them to not be const pointers.

Verified that

make -C tools/lib/bpf
make -C tools/testing/selftests/bpf
make -C tools/perf

all build without warnings.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-19 02:21:02 +02:00
David S. Miller 13091aa305 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Honestly all the conflicts were simple overlapping changes,
nothing really interesting to report.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-17 20:20:36 -07:00
Andrii Nakryiko abd29c9314 libbpf: allow specifying map definitions using BTF
This patch adds support for a new way to define BPF maps. It relies on
BTF to describe mandatory and optional attributes of a map, as well as
captures type information of key and value naturally. This eliminates
the need for BPF_ANNOTATE_KV_PAIR hack and ensures key/value sizes are
always in sync with the key/value type.

Relying on BTF, this approach allows for both forward and backward
compatibility w.r.t. extending supported map definition features. By
default, any unrecognized attributes are treated as an error, but it's
possible relax this using MAPS_RELAX_COMPAT flag. New attributes, added
in the future will need to be optional.

The outline of the new map definition (short, BTF-defined maps) is as follows:
1. All the maps should be defined in .maps ELF section. It's possible to
   have both "legacy" map definitions in `maps` sections and BTF-defined
   maps in .maps sections. Everything will still work transparently.
2. The map declaration and initialization is done through
   a global/static variable of a struct type with few mandatory and
   extra optional fields:
   - type field is mandatory and specified type of BPF map;
   - key/value fields are mandatory and capture key/value type/size information;
   - max_entries attribute is optional; if max_entries is not specified or
     initialized, it has to be provided in runtime through libbpf API
     before loading bpf_object;
   - map_flags is optional and if not defined, will be assumed to be 0.
3. Key/value fields should be **a pointer** to a type describing
   key/value. The pointee type is assumed (and will be recorded as such
   and used for size determination) to be a type describing key/value of
   the map. This is done to save excessive amounts of space allocated in
   corresponding ELF sections for key/value of big size.
4. As some maps disallow having BTF type ID associated with key/value,
   it's possible to specify key/value size explicitly without
   associating BTF type ID with it. Use key_size and value_size fields
   to do that (see example below).

Here's an example of simple ARRAY map defintion:

struct my_value { int x, y, z; };

struct {
	int type;
	int max_entries;
	int *key;
	struct my_value *value;
} btf_map SEC(".maps") = {
	.type = BPF_MAP_TYPE_ARRAY,
	.max_entries = 16,
};

This will define BPF ARRAY map 'btf_map' with 16 elements. The key will
be of type int and thus key size will be 4 bytes. The value is struct
my_value of size 12 bytes. This map can be used from C code exactly the
same as with existing maps defined through struct bpf_map_def.

Here's an example of STACKMAP definition (which currently disallows BTF type
IDs for key/value):

struct {
	__u32 type;
	__u32 max_entries;
	__u32 map_flags;
	__u32 key_size;
	__u32 value_size;
} stackmap SEC(".maps") = {
	.type = BPF_MAP_TYPE_STACK_TRACE,
	.max_entries = 128,
	.map_flags = BPF_F_STACK_BUILD_ID,
	.key_size = sizeof(__u32),
	.value_size = PERF_MAX_STACK_DEPTH * sizeof(struct bpf_stack_build_id),
};

This approach is naturally extended to support map-in-map, by making a value
field to be another struct that describes inner map. This feature is not
implemented yet. It's also possible to incrementally add features like pinning
with full backwards and forward compatibility. Support for static
initialization of BPF_MAP_TYPE_PROG_ARRAY using pointers to BPF programs
is also on the roadmap.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-18 00:10:41 +02:00
Andrii Nakryiko 063183bf04 libbpf: split initialization and loading of BTF
Libbpf does sanitization of BTF before loading it into kernel, if kernel
doesn't support some of newer BTF features. This removes some of the
important information from BTF (e.g., DATASEC and VAR description),
which will be used for map construction. This patch splits BTF
processing into initialization step, in which BTF is initialized from
ELF and all the original data is still preserved; and
sanitization/loading step, which ensures that BTF is safe to load into
kernel. This allows to use full BTF information to construct maps, while
still loading valid BTF into older kernels.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-18 00:10:41 +02:00
Andrii Nakryiko db48814bd2 libbpf: identify maps by section index in addition to offset
To support maps to be defined in multiple sections, it's important to
identify map not just by offset within its section, but section index as
well. This patch adds tracking of section index.

For global data, we record section index of corresponding
.data/.bss/.rodata ELF section for uniformity, and thus don't need
a special value of offset for those maps.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-18 00:10:40 +02:00
Andrii Nakryiko bf82927125 libbpf: refactor map initialization
User and global data maps initialization has gotten pretty complicated
and unnecessarily convoluted. This patch splits out the logic for global
data map and user-defined map initialization. It also removes the
restriction of pre-calculating how many maps will be initialized,
instead allowing to keep adding new maps as they are discovered, which
will be used later for BTF-defined map definitions.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-18 00:10:39 +02:00
Andrii Nakryiko 01b29d1dc9 libbpf: streamline ELF parsing error-handling
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>
2019-06-18 00:10:39 +02:00
Andrii Nakryiko 9c6660d040 libbpf: extract BTF loading logic
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>
2019-06-18 00:10:12 +02:00
Andrii Nakryiko d7fe74f940 libbpf: add common min/max macro to libbpf_internal.h
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>
2019-06-18 00:08:54 +02:00
Andrii Nakryiko e55d54f43d libbpf: fix check for presence of associated BTF for map creation
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: fba01a0689 ("libbpf: use negative fd to specify missing BTF")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 01:14:08 +02:00
Hechao Li 6446b31555 bpf: add a new API libbpf_num_possible_cpus()
Adding a new API libbpf_num_possible_cpus() that helps user with
per-CPU map operations.

Signed-off-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-11 10:36:02 +02:00
Jonathan Lemon 10a13bb40e libbpf: remove qidconf and better support external bpf programs.
Use the recent change to XSKMAP bpf_map_lookup_elem() to test if
there is a xsk present in the map instead of duplicating the work
with qidconf.

Fix things so callers using XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD
bypass any internal bpf maps, so xsk_socket__{create|delete} works
properly.

Clean up error handling path.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-10 23:31:26 -07:00
Daniel Borkmann 9bb59ac1f6 bpf, libbpf: enable recvmsg attach types
Another trivial patch to libbpf in order to enable identifying and
attaching programs to BPF_CGROUP_UDP{4,6}_RECVMSG by section name.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-06 16:53:12 -07:00
Michal Rostecki cfd4921049 libbpf: Return btf_fd for load_sk_storage_btf
Before this change, function load_sk_storage_btf expected that
libbpf__probe_raw_btf was returning a BTF descriptor, but in fact it was
returning an information about whether the probe was successful (0 or
1). load_sk_storage_btf was using that value as an argument of the close
function, which was resulting in closing stdout and thus terminating the
process which called that function.

That bug was visible in bpftool. `bpftool feature` subcommand was always
exiting too early (because of closed stdout) and it didn't display all
requested probes. `bpftool -j feature` or `bpftool -p feature` were not
returning a valid json object.

This change renames the libbpf__probe_raw_btf function to
libbpf__load_raw_btf, which now returns a BTF descriptor, as expected in
load_sk_storage_btf.

v2:
- Fix typo in the commit message.

v3:
- Simplify BTF descriptor handling in bpf_object__probe_btf_* functions.
- Rename libbpf__probe_raw_btf function to libbpf__load_raw_btf and
return a BTF descriptor.

v4:
- Fix typo in the commit message.

Fixes: d7c4b3980c ("libbpf: detect supported kernel BTF features and sanitize BTF")
Signed-off-by: Michal Rostecki <mrostecki@opensuse.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-31 17:03:39 -07:00
Andrii Nakryiko 399dc65e9c libbpf: reduce unnecessary line wrapping
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>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko 76e1022b96 libbpf: typo and formatting fixes
A bunch of typo and formatting fixes.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko 7e8c328c4e libbpf: simplify two pieces of logic
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>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko fba01a0689 libbpf: use negative fd to specify missing BTF
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>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko f102154d31 libbpf: fix error code returned on corrupted ELF
All of libbpf errors are negative, except this one. Fix it.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko c51829bb6e libbpf: check map name retrieved from ELF
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>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko 12ef5634a8 libbpf: simplify endianness check
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>
2019-05-30 01:23:35 +02:00
Andrii Nakryiko be5c5d4e9d libbpf: preserve errno before calling into user callback
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>
2019-05-30 01:23:34 +02:00
Andrii Nakryiko 8ca990ce0d libbpf: fix detection of corrupted BPF instructions section
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>
2019-05-30 01:23:34 +02:00
Quentin Monnet 501b125a29 libbpf: prevent overwriting of log_level in bpf_object__load_progs()
There are two functions in libbpf that support passing a log_level
parameter for the verifier for loading programs:
bpf_object__load_xattr() and bpf_prog_load_xattr(). Both accept an
attribute object containing the log_level, and apply it to the programs
to load.

It turns out that to effectively load the programs, the latter function
eventually relies on the former. This was not taken into account when
adding support for log_level in bpf_object__load_xattr(), and the
log_level passed to bpf_prog_load_xattr() later gets overwritten with a
zero value, thus disabling verifier logs for the program in all cases:

bpf_prog_load_xattr()             // prog->log_level = attr1->log_level;
-> bpf_object__load()             // attr2->log_level = 0;
   -> bpf_object__load_xattr()    // <pass prog and attr2>
      -> bpf_object__load_progs() // prog->log_level = attr2->log_level;

Fix this by OR-ing the log_level in bpf_object__load_progs(), instead of
overwriting it.

v2: Fix commit log description (confusion on function names in v1).

Fixes: 60276f9849 ("libbpf: add bpf_object__load_xattr() API function to pass log_level")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-29 19:36:55 +02:00
Quentin Monnet 60276f9849 libbpf: add bpf_object__load_xattr() API function to pass log_level
libbpf was recently made aware of the log_level attribute for programs,
used to specify the level of information expected to be dumped by the
verifier. Function bpf_prog_load_xattr() got support for this log_level
parameter.

But some applications using libbpf rely on another function to load
programs, bpf_object__load(), which does accept any parameter for log
level. Create an API function based on bpf_object__load(), but accepting
an "attr" object as a parameter. Then add a log_level field to that
object, so that applications calling the new bpf_object__load_xattr()
can pick the desired log level.

v3:
- Rewrite commit log.

v2:
- We are in a new cycle, bump libbpf extraversion number.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-28 11:03:26 +02:00
Hariprasad Kelam d98363b510 libbpf: fix warning that PTR_ERR_OR_ZERO can be used
Fix below warning reported by coccicheck:

/tools/lib/bpf/libbpf.c:3461:1-3: WARNING: PTR_ERR_OR_ZERO can be used

Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-28 10:56:05 +02:00
Jiong Wang 046561981b libbpf: add "prog_flags" to bpf_program/bpf_prog_load_attr/bpf_load_program_attr
libbpf doesn't allow passing "prog_flags" during bpf program load in a
couple of load related APIs, "bpf_load_program_xattr", "load_program" and
"bpf_prog_load_xattr".

It makes sense to allow passing "prog_flags" which is useful for
customizing program loading.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-24 18:58:37 -07:00
Andrii Nakryiko 351131b51c libbpf: add btf_dump API for BTF-to-C conversion
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>
2019-05-24 14:05:58 -07:00
Andrii Nakryiko 2fc3fc0bcd libbpf: switch btf_dedup() to hashmap for dedup table
Utilize libbpf's hashmap as a multimap fof dedup_table implementation.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-24 14:05:58 -07:00
Andrii Nakryiko e3b9242240 libbpf: add resizable non-thread safe internal hashmap
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>
2019-05-24 14:05:57 -07:00