Merge branch 'libbpf:master' into master

Update checked in vmlinux.h for 5.5 kernel tests.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

.github/actions/build-selftests/action.yml

@@ -18,9 +18,10 @@ runs:
   steps:
     - shell: bash
       run: |
-        echo "::group::Setup Env"
+        source $GITHUB_ACTION_PATH/../../../ci/vmtest/helpers.sh
+        foldable start "Setup Env"
         sudo apt-get install -y qemu-kvm zstd binutils-dev elfutils libcap-dev libelf-dev libdw-dev python3-docutils
-        echo "::endgroup::"
+        foldable end
     - shell: bash
       run: |
         export KERNEL=${{ inputs.kernel }}

.github/actions/vmtest/action.yml

@@ -41,24 +41,26 @@ runs:
     - name: Prepare to build BPF selftests
       shell: bash
       run: |
-        echo "::group::Prepare building selftest"
+        source $GITHUB_ACTION_PATH/../../../ci/vmtest/helpers.sh
+        foldable start "Prepare building selftest"
         cd .kernel
         cat tools/testing/selftests/bpf/config \
             tools/testing/selftests/bpf/config.${{ inputs.arch }} > .config
         make olddefconfig && make prepare
         cd -
-        echo "::endgroup::"
+        foldable end
     # 2. if kernel == LATEST, build kernel image from tree
     - name: Build kernel image
       if: ${{ inputs.kernel == 'LATEST' }}
       shell: bash
       run: |
-        echo "::group::Build Kernel Image"
+        source $GITHUB_ACTION_PATH/../../../ci/vmtest/helpers.sh
+        foldable start "Build Kernel Image"
         cd .kernel
         make -j $((4*$(nproc))) all > /dev/null
         cp vmlinux ${{ github.workspace }}
         cd -
-        echo "::endgroup::"
+        foldable end
     # else, just download prebuilt kernel image
     - name: Download prebuilt kernel
       if: ${{ inputs.kernel != 'LATEST' }}
@@ -76,14 +78,19 @@ runs:
     - name: prepare rootfs
       uses: libbpf/ci/prepare-rootfs@master
       with:
-        kernel: ${{ inputs.kernel }}
         project-name: 'libbpf'
         arch: ${{ inputs.arch }}
+        kernel: ${{ inputs.kernel }}
+        kernel-root: '.kernel'
         image-output: '/tmp/root.img'
     # 5. run selftest in QEMU
     - name: Run selftests
+      env:
+        KERNEL: ${{ inputs.kernel }}
+        REPO_ROOT: ${{ github.workspace }}
       uses: libbpf/ci/run-qemu@master
       with:
+        arch: ${{ inputs.arch }}
         img: '/tmp/root.img'
         vmlinuz: 'vmlinuz'
-        arch: ${{ inputs.arch }}
+        kernel-root: '.kernel'

.github/workflows/coverity.yml

@@ -15,12 +15,13 @@ jobs:
       - uses: ./.github/actions/setup
       - name: Run coverity
         run: |
-          echo ::group::Setup CI env
+          source "${GITHUB_WORKSPACE}"/ci/vmtest/helpers.sh
+          foldable start "Setup CI env"
           source /tmp/ci_setup
           export COVERITY_SCAN_NOTIFICATION_EMAIL="${AUTHOR_EMAIL}"
           export COVERITY_SCAN_BRANCH_PATTERN=${GITHUB_REF##refs/*/}
           export TRAVIS_BRANCH=${COVERITY_SCAN_BRANCH_PATTERN}
-          echo ::endgroup::
+          foldable end
           scripts/coverity.sh
         env:
           COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-14b20b784f59bdd95f6f1cfb112c9818bcec4d84
+60240bc26114543fcbfcd8a28466e67e77b20388

CHECKPOINT-COMMIT

@@ -1 +1 @@
-e34cfee65ec891a319ce79797dda18083af33a76
+87dbdc230d162bf9ee1ac77c8ade178b6b1e199e

README.md

@@ -1,4 +1,7 @@
-<img src="https://user-images.githubusercontent.com/508075/185997470-2f427d3d-f040-4eef-afc5-ae4f766615b2.png" width="40%" >
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="assets/libbpf-logo-sideways-darkbg.png" width="40%">
+  <img src="assets/libbpf-logo-sideways.png" width="40%">
+</picture>
 
 libbpf
 [![Github Actions Builds & Tests](https://github.com/libbpf/libbpf/actions/workflows/test.yml/badge.svg)](https://github.com/libbpf/libbpf/actions/workflows/test.yml)

ci/rootfs/s390x-self-hosted-builder/README.md

@@ -36,6 +36,7 @@ $ sudo systemctl daemon-reload
 $ sudo tee /etc/actions-runner-libbpf
 repo=<owner>/<name>
 access_token=<ghp_***>
+runner_name=<hostname>
 ```
 
 Access token should have the repo scope, consult

ci/rootfs/s390x-self-hosted-builder/actions-runner-libbpf.Dockerfile

@@ -24,7 +24,9 @@ RUN apt-get update && apt-get -y install \
         rsync \
         software-properties-common \
         sudo \
-        tree
+        tree \
+        iproute2 \
+        iputils-ping
 
 # amd64 dependencies.
 COPY --from=ld-prefix / /usr/x86_64-linux-gnu/
@@ -33,7 +35,7 @@ RUN ln -fs /etc/resolv.conf /usr/x86_64-linux-gnu/etc/
 ENV QEMU_LD_PREFIX=/usr/x86_64-linux-gnu
 
 # amd64 Github Actions Runner.
-ARG version=2.285.0
+ARG version=2.296.0
 RUN useradd -m actions-runner
 RUN echo "actions-runner ALL=(ALL) NOPASSWD: ALL" >>/etc/sudoers
 RUN echo "Defaults env_keep += \"DEBIAN_FRONTEND\"" >>/etc/sudoers

ci/rootfs/s390x-self-hosted-builder/fs/usr/bin/actions-runner

@@ -7,7 +7,7 @@
 #
 # - repo=<owner>/<name>
 # - access_token=<ghp_***>
-#
+# - runner_name=<hostname>
 
 set -e -u
 
@@ -34,6 +34,7 @@ registration_token=$(jq --raw-output .token "$token_file")
     --url "https://github.com/$repo" \
     --token "$registration_token" \
     --labels z15 \
+    --name "$runner_name" \
     --ephemeral
 
 # Run one job.

ci/vmtest/configs/DENYLIST-5.5.0

@@ -1,5 +1,5 @@
 # This file is not used and is there for historic purposes only.
-# See WHITELIST-5.5.0 instead.
+# See ALLOWLIST-5.5.0 instead.
 
 # PERMANENTLY DISABLED
 align			# verifier output format changed

ci/vmtest/configs/DENYLIST-latest

@@ -1,6 +0,0 @@
-# TEMPORARY
-get_stack_raw_tp    # spams with kernel warnings until next bpf -> bpf-next merge
-stacktrace_build_id_nmi
-stacktrace_build_id
-task_fd_query_rawtp
-varlen

ci/vmtest/configs/DENYLIST-latest.s390x

@@ -1,68 +1,6 @@
+# TEMPORARY until bpf-next -> bpf merge
+lru_bug                                  # prog 'printk': failed to auto-attach: -524
+
 # TEMPORARY
-atomics                                  # attach(add): actual -524 <= expected 0                                      (trampoline)
-bpf_iter_setsockopt                      # JIT does not support calling kernel function                                (kfunc)
-bloom_filter_map                         # failed to find kernel BTF type ID of '__x64_sys_getpgid': -3                (?)
-bpf_tcp_ca                               # JIT does not support calling kernel function                                (kfunc)
-bpf_loop                                 # attaches to __x64_sys_nanosleep
-bpf_mod_race                             # BPF trampoline
-bpf_nf                                   # JIT does not support calling kernel function
-core_read_macros                         # unknown func bpf_probe_read#4                                               (overlapping)
-d_path                                   # failed to auto-attach program 'prog_stat': -524                             (trampoline)
-dummy_st_ops                             # test_run unexpected error: -524 (errno 524)                                 (trampoline)
-fentry_fexit                             # fentry attach failed: -524                                                  (trampoline)
-fentry_test                              # fentry_first_attach unexpected error: -524                                  (trampoline)
-fexit_bpf2bpf                            # freplace_attach_trace unexpected error: -524                                (trampoline)
-fexit_sleep                              # fexit_skel_load fexit skeleton failed                                       (trampoline)
-fexit_stress                             # fexit attach failed prog 0 failed: -524                                     (trampoline)
-fexit_test                               # fexit_first_attach unexpected error: -524                                   (trampoline)
-get_func_args_test	                 # trampoline
-get_func_ip_test                         # get_func_ip_test__attach unexpected error: -524                             (trampoline)
-get_stack_raw_tp                         # user_stack corrupted user stack                                             (no backchain userspace)
-kfree_skb                                # attach fentry unexpected error: -524                                        (trampoline)
-kfunc_call                               # 'bpf_prog_active': not found in kernel BTF                                  (?)
-ksyms_module                             # test_ksyms_module__open_and_load unexpected error: -9                       (?)
-ksyms_module_libbpf                      # JIT does not support calling kernel function                                (kfunc)
-ksyms_module_lskel                       # test_ksyms_module_lskel__open_and_load unexpected error: -9                 (?)
-modify_return                            # modify_return attach failed: -524                                           (trampoline)
-module_attach                            # skel_attach skeleton attach failed: -524                                    (trampoline)
-mptcp
-kprobe_multi_test                        # relies on fentry
-netcnt                                   # failed to load BPF skeleton 'netcnt_prog': -7                               (?)
-probe_user                               # check_kprobe_res wrong kprobe res from probe read                           (?)
-recursion                                # skel_attach unexpected error: -524                                          (trampoline)
-ringbuf                                  # skel_load skeleton load failed                                              (?)
-sk_assign                                # Can't read on server: Invalid argument                                      (?)
-sk_lookup                                # endianness problem
-sk_storage_tracing                       # test_sk_storage_tracing__attach unexpected error: -524                      (trampoline)
-skc_to_unix_sock                         # could not attach BPF object unexpected error: -524                          (trampoline)
-socket_cookie                            # prog_attach unexpected error: -524                                          (trampoline)
-stacktrace_build_id                      # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2                   (?)
-tailcalls                                # tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls      (?)
-task_local_storage                       # failed to auto-attach program 'trace_exit_creds': -524                      (trampoline)
-test_bpffs                               # bpffs test  failed 255                                                      (iterator)
-test_bprm_opts                           # failed to auto-attach program 'secure_exec': -524                           (trampoline)
-test_ima                                 # failed to auto-attach program 'ima': -524                                   (trampoline)
-test_local_storage                       # failed to auto-attach program 'unlink_hook': -524                           (trampoline)
-test_lsm                                 # failed to find kernel BTF type ID of '__x64_sys_setdomainname': -3          (?)
-test_overhead                            # attach_fentry unexpected error: -524                                        (trampoline)
-test_profiler                            # unknown func bpf_probe_read_str#45                                          (overlapping)
-timer                                    # failed to auto-attach program 'test1': -524                                 (trampoline)
-timer_crash                              # trampoline
-timer_mim                                # failed to auto-attach program 'test1': -524                                 (trampoline)
-trace_ext                                # failed to auto-attach program 'test_pkt_md_access_new': -524                (trampoline)
-trace_printk                             # trace_printk__load unexpected error: -2 (errno 2)                           (?)
-trace_vprintk                            # trace_vprintk__open_and_load unexpected error: -9                           (?)
-trampoline_count                         # prog 'prog1': failed to attach: ERROR: strerror_r(-524)=22                  (trampoline)
-verif_stats                              # trace_vprintk__open_and_load unexpected error: -9                           (?)
-vmlinux                                  # failed to auto-attach program 'handle__fentry': -524                        (trampoline)
-xdp_adjust_tail                          # case-128 err 0 errno 28 retval 1 size 128 expect-size 3520                  (?)
-xdp_bonding                              # failed to auto-attach program 'trace_on_entry': -524                        (trampoline)
-xdp_bpf2bpf                              # failed to auto-attach program 'trace_on_entry': -524                        (trampoline)
-map_kptr                                 # failed to open_and_load program: -524 (trampoline)
-bpf_cookie                               # failed to open_and_load program: -524 (trampoline)
-xdp_do_redirect                          # prog_run_max_size unexpected error: -22 (errno 22)
-send_signal                              # intermittently fails to receive signal
-select_reuseport                         # intermittently fails on new s390x setup
-xdp_synproxy                             # JIT does not support calling kernel function                                (kfunc)
-unpriv_bpf_disabled                      # fentry
-lru_bug
+usdt/basic                               # failing verifier due to bounds check after LLVM update
+usdt/multispec                           # same as above

ci/vmtest/run_selftests.sh

@@ -28,7 +28,7 @@ test_progs() {
 	fi
 }
 
-test_progs_noalu() {
+test_progs_no_alu32() {
 	foldable start test_progs-no_alu32 "Testing test_progs-no_alu32"
 	./test_progs-no_alu32 ${DENYLIST:+-d$DENYLIST} ${ALLOWLIST:+-a$ALLOWLIST} && true
 	echo "test_progs-no_alu32:$?" >> "${STATUS_FILE}"
@@ -55,9 +55,20 @@ test_verifier() {
 
 foldable end vm_init
 
-configs_path=${PROJECT_NAME}/vmtest/configs
-DENYLIST=$(read_lists "$configs_path/DENYLIST-${KERNEL}" "$configs_path/DENYLIST-${KERNEL}.${ARCH}")
-ALLOWLIST=$(read_lists "$configs_path/ALLOWLIST-${KERNEL}" "$configs_path/ALLOWLIST-${KERNEL}.${ARCH}")
+configs_path=/${PROJECT_NAME}/selftests/bpf
+local_configs_path=${PROJECT_NAME}/vmtest/configs
+DENYLIST=$(read_lists \
+	"$configs_path/DENYLIST" \
+	"$configs_path/DENYLIST.${ARCH}" \
+	"$local_configs_path/DENYLIST-${KERNEL}" \
+	"$local_configs_path/DENYLIST-${KERNEL}.${ARCH}" \
+)
+ALLOWLIST=$(read_lists \
+	"$configs_path/ALLOWLIST" \
+	"$configs_path/ALLOWLIST.${ARCH}" \
+	"$local_configs_path/ALLOWLIST-${KERNEL}" \
+	"$local_configs_path/ALLOWLIST-${KERNEL}.${ARCH}" \
+)
 
 echo "DENYLIST: ${DENYLIST}"
 echo "ALLOWLIST: ${ALLOWLIST}"
@@ -66,7 +77,7 @@ cd ${PROJECT_NAME}/selftests/bpf
 
 if [ $# -eq 0 ]; then
 	test_progs
-	test_progs_noalu
+	test_progs_no_alu32
 	test_maps
 	test_verifier
 else

include/uapi/linux/bpf.h

@@ -87,10 +87,29 @@ struct bpf_cgroup_storage_key {
 	__u32	attach_type;		/* program attach type (enum bpf_attach_type) */
 };
 
+enum bpf_cgroup_iter_order {
+	BPF_CGROUP_ITER_ORDER_UNSPEC = 0,
+	BPF_CGROUP_ITER_SELF_ONLY,		/* process only a single object. */
+	BPF_CGROUP_ITER_DESCENDANTS_PRE,	/* walk descendants in pre-order. */
+	BPF_CGROUP_ITER_DESCENDANTS_POST,	/* walk descendants in post-order. */
+	BPF_CGROUP_ITER_ANCESTORS_UP,		/* walk ancestors upward. */
+};
+
 union bpf_iter_link_info {
 	struct {
 		__u32	map_fd;
 	} map;
+	struct {
+		enum bpf_cgroup_iter_order order;
+
+		/* At most one of cgroup_fd and cgroup_id can be non-zero. If
+		 * both are zero, the walk starts from the default cgroup v2
+		 * root. For walking v1 hierarchy, one should always explicitly
+		 * specify cgroup_fd.
+		 */
+		__u32	cgroup_fd;
+		__u64	cgroup_id;
+	} cgroup;
 };
 
 /* BPF syscall commands, see bpf(2) man-page for more details. */
@@ -909,6 +928,7 @@ enum bpf_map_type {
 	BPF_MAP_TYPE_INODE_STORAGE,
 	BPF_MAP_TYPE_TASK_STORAGE,
 	BPF_MAP_TYPE_BLOOM_FILTER,
+	BPF_MAP_TYPE_USER_RINGBUF,
 };
 
 /* Note that tracing related programs such as
@@ -1233,7 +1253,7 @@ enum {
 
 /* Query effective (directly attached + inherited from ancestor cgroups)
  * programs that will be executed for events within a cgroup.
- * attach_flags with this flag are returned only for directly attached programs.
+ * attach_flags with this flag are always returned 0.
  */
 #define BPF_F_QUERY_EFFECTIVE	(1U << 0)
 
@@ -1432,7 +1452,10 @@ union bpf_attr {
 		__u32		attach_flags;
 		__aligned_u64	prog_ids;
 		__u32		prog_cnt;
-		__aligned_u64	prog_attach_flags; /* output: per-program attach_flags */
+		/* output: per-program attach_flags.
+		 * not allowed to be set during effective query.
+		 */
+		__aligned_u64	prog_attach_flags;
 	} query;
 
 	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
@@ -4437,7 +4460,7 @@ union bpf_attr {
  *
  *		**-EEXIST** if the option already exists.
  *
- *		**-EFAULT** on failrue to parse the existing header options.
+ *		**-EFAULT** on failure to parse the existing header options.
  *
  *		**-EPERM** if the helper cannot be used under the current
  *		*skops*\ **->op**.
@@ -4646,7 +4669,7 @@ union bpf_attr {
  *		a *map* with *task* as the **key**.  From this
  *		perspective,  the usage is not much different from
  *		**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
- *		helper enforces the key must be an task_struct and the map must also
+ *		helper enforces the key must be a task_struct and the map must also
  *		be a **BPF_MAP_TYPE_TASK_STORAGE**.
  *
  *		Underneath, the value is stored locally at *task* instead of
@@ -4704,7 +4727,7 @@ union bpf_attr {
  *
  * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size)
  *	Description
- *		Returns the stored IMA hash of the *inode* (if it's avaialable).
+ *		Returns the stored IMA hash of the *inode* (if it's available).
  *		If the hash is larger than *size*, then only *size*
  *		bytes will be copied to *dst*
  *	Return
@@ -4728,12 +4751,12 @@ union bpf_attr {
  *
  *		The argument *len_diff* can be used for querying with a planned
  *		size change. This allows to check MTU prior to changing packet
- *		ctx. Providing an *len_diff* adjustment that is larger than the
+ *		ctx. Providing a *len_diff* adjustment that is larger than the
  *		actual packet size (resulting in negative packet size) will in
- *		principle not exceed the MTU, why it is not considered a
- *		failure.  Other BPF-helpers are needed for performing the
- *		planned size change, why the responsability for catch a negative
- *		packet size belong in those helpers.
+ *		principle not exceed the MTU, which is why it is not considered
+ *		a failure.  Other BPF helpers are needed for performing the
+ *		planned size change; therefore the responsibility for catching
+ *		a negative packet size belongs in those helpers.
  *
  *		Specifying *ifindex* zero means the MTU check is performed
  *		against the current net device.  This is practical if this isn't
@@ -4931,6 +4954,7 @@ union bpf_attr {
  * 		Get address of the traced function (for tracing and kprobe programs).
  * 	Return
  * 		Address of the traced function.
+ * 		0 for kprobes placed within the function (not at the entry).
  *
  * u64 bpf_get_attach_cookie(void *ctx)
  * 	Description
@@ -5060,12 +5084,12 @@ union bpf_attr {
  *
  * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
  *	Description
- *		Get **n**-th argument (zero based) of the traced function (for tracing programs)
+ *		Get **n**-th argument register (zero based) of the traced function (for tracing programs)
  *		returned in **value**.
  *
  *	Return
  *		0 on success.
- *		**-EINVAL** if n >= arguments count of traced function.
+ *		**-EINVAL** if n >= argument register count of traced function.
  *
  * long bpf_get_func_ret(void *ctx, u64 *value)
  *	Description
@@ -5078,24 +5102,37 @@ union bpf_attr {
  *
  * long bpf_get_func_arg_cnt(void *ctx)
  *	Description
- *		Get number of arguments of the traced function (for tracing programs).
+ *		Get number of registers of the traced function (for tracing programs) where
+ *		function arguments are stored in these registers.
  *
  *	Return
- *		The number of arguments of the traced function.
+ *		The number of argument registers of the traced function.
  *
  * int bpf_get_retval(void)
  *	Description
- *		Get the syscall's return value that will be returned to userspace.
+ *		Get the BPF program's return value that will be returned to the upper layers.
  *
- *		This helper is currently supported by cgroup programs only.
+ *		This helper is currently supported by cgroup programs and only by the hooks
+ *		where BPF program's return value is returned to the userspace via errno.
  *	Return
- *		The syscall's return value.
+ *		The BPF program's return value.
  *
  * int bpf_set_retval(int retval)
  *	Description
- *		Set the syscall's return value that will be returned to userspace.
+ *		Set the BPF program's return value that will be returned to the upper layers.
+ *
+ *		This helper is currently supported by cgroup programs and only by the hooks
+ *		where BPF program's return value is returned to the userspace via errno.
+ *
+ *		Note that there is the following corner case where the program exports an error
+ *		via bpf_set_retval but signals success via 'return 1':
+ *
+ *			bpf_set_retval(-EPERM);
+ *			return 1;
+ *
+ *		In this case, the BPF program's return value will use helper's -EPERM. This
+ *		still holds true for cgroup/bind{4,6} which supports extra 'return 3' success case.
  *
- *		This helper is currently supported by cgroup programs only.
  *	Return
  *		0 on success, or a negative error in case of failure.
  *
@@ -5355,6 +5392,43 @@ union bpf_attr {
  *	Return
  *		Current *ktime*.
  *
+ * long bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx, u64 flags)
+ *	Description
+ *		Drain samples from the specified user ring buffer, and invoke
+ *		the provided callback for each such sample:
+ *
+ *		long (\*callback_fn)(struct bpf_dynptr \*dynptr, void \*ctx);
+ *
+ *		If **callback_fn** returns 0, the helper will continue to try
+ *		and drain the next sample, up to a maximum of
+ *		BPF_MAX_USER_RINGBUF_SAMPLES samples. If the return value is 1,
+ *		the helper will skip the rest of the samples and return. Other
+ *		return values are not used now, and will be rejected by the
+ *		verifier.
+ *	Return
+ *		The number of drained samples if no error was encountered while
+ *		draining samples, or 0 if no samples were present in the ring
+ *		buffer. If a user-space producer was epoll-waiting on this map,
+ *		and at least one sample was drained, they will receive an event
+ *		notification notifying them of available space in the ring
+ *		buffer. If the BPF_RB_NO_WAKEUP flag is passed to this
+ *		function, no wakeup notification will be sent. If the
+ *		BPF_RB_FORCE_WAKEUP flag is passed, a wakeup notification will
+ *		be sent even if no sample was drained.
+ *
+ *		On failure, the returned value is one of the following:
+ *
+ *		**-EBUSY** if the ring buffer is contended, and another calling
+ *		context was concurrently draining the ring buffer.
+ *
+ *		**-EINVAL** if user-space is not properly tracking the ring
+ *		buffer due to the producer position not being aligned to 8
+ *		bytes, a sample not being aligned to 8 bytes, or the producer
+ *		position not matching the advertised length of a sample.
+ *
+ *		**-E2BIG** if user-space has tried to publish a sample which is
+ *		larger than the size of the ring buffer, or which cannot fit
+ *		within a struct bpf_dynptr.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5566,6 +5640,7 @@ union bpf_attr {
 	FN(tcp_raw_check_syncookie_ipv4),	\
 	FN(tcp_raw_check_syncookie_ipv6),	\
 	FN(ktime_get_tai_ns),		\
+	FN(user_ringbuf_drain),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
@@ -5628,6 +5703,11 @@ enum {
 	BPF_F_SEQ_NUMBER		= (1ULL << 3),
 };
 
+/* BPF_FUNC_skb_get_tunnel_key flags. */
+enum {
+	BPF_F_TUNINFO_FLAGS		= (1ULL << 4),
+};
+
 /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
  * BPF_FUNC_perf_event_read_value flags.
  */
@@ -5817,7 +5897,10 @@ struct bpf_tunnel_key {
 	};
 	__u8 tunnel_tos;
 	__u8 tunnel_ttl;
-	__u16 tunnel_ext;	/* Padding, future use. */
+	union {
+		__u16 tunnel_ext;	/* compat */
+		__be16 tunnel_flags;
+	};
 	__u32 tunnel_label;
 	union {
 		__u32 local_ipv4;
@@ -5861,6 +5944,11 @@ enum bpf_ret_code {
 	 *    represented by BPF_REDIRECT above).
 	 */
 	BPF_LWT_REROUTE = 128,
+	/* BPF_FLOW_DISSECTOR_CONTINUE: used by BPF_PROG_TYPE_FLOW_DISSECTOR
+	 *   to indicate that no custom dissection was performed, and
+	 *   fallback to standard dissector is requested.
+	 */
+	BPF_FLOW_DISSECTOR_CONTINUE = 129,
 };
 
 struct bpf_sock {
@@ -6159,11 +6247,22 @@ struct bpf_link_info {
 		struct {
 			__aligned_u64 target_name; /* in/out: target_name buffer ptr */
 			__u32 target_name_len;	   /* in/out: target_name buffer len */
+
+			/* If the iter specific field is 32 bits, it can be put
+			 * in the first or second union. Otherwise it should be
+			 * put in the second union.
+			 */
 			union {
 				struct {
 					__u32 map_id;
 				} map;
 			};
+			union {
+				struct {
+					__u64 cgroup_id;
+					__u32 order;
+				} cgroup;
+			};
 		} iter;
 		struct  {
 			__u32 netns_ino;

src/Makefile

@@ -9,7 +9,7 @@ else
 endif
 
 LIBBPF_MAJOR_VERSION := 1
-LIBBPF_MINOR_VERSION := 0
+LIBBPF_MINOR_VERSION := 1
 LIBBPF_PATCH_VERSION := 0
 LIBBPF_VERSION := $(LIBBPF_MAJOR_VERSION).$(LIBBPF_MINOR_VERSION).$(LIBBPF_PATCH_VERSION)
 LIBBPF_MAJMIN_VERSION := $(LIBBPF_MAJOR_VERSION).$(LIBBPF_MINOR_VERSION).0

src/bpf_helper_defs.h

@@ -3426,7 +3426,7 @@ static long (*bpf_load_hdr_opt)(struct bpf_sock_ops *skops, void *searchby_res,
  *
  * 	**-EEXIST** if the option already exists.
  *
- * 	**-EFAULT** on failrue to parse the existing header options.
+ * 	**-EFAULT** on failure to parse the existing header options.
  *
  * 	**-EPERM** if the helper cannot be used under the current
  * 	*skops*\ **->op**.
@@ -3686,7 +3686,7 @@ static long (*bpf_redirect_peer)(__u32 ifindex, __u64 flags) = (void *) 155;
  * 	a *map* with *task* as the **key**.  From this
  * 	perspective,  the usage is not much different from
  * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
- * 	helper enforces the key must be an task_struct and the map must also
+ * 	helper enforces the key must be a task_struct and the map must also
  * 	be a **BPF_MAP_TYPE_TASK_STORAGE**.
  *
  * 	Underneath, the value is stored locally at *task* instead of
@@ -3764,7 +3764,7 @@ static __u64 (*bpf_ktime_get_coarse_ns)(void) = (void *) 160;
 /*
  * bpf_ima_inode_hash
  *
- * 	Returns the stored IMA hash of the *inode* (if it's avaialable).
+ * 	Returns the stored IMA hash of the *inode* (if it's available).
  * 	If the hash is larger than *size*, then only *size*
  * 	bytes will be copied to *dst*
  *
@@ -3796,12 +3796,12 @@ static struct socket *(*bpf_sock_from_file)(struct file *file) = (void *) 162;
  *
  * 	The argument *len_diff* can be used for querying with a planned
  * 	size change. This allows to check MTU prior to changing packet
- * 	ctx. Providing an *len_diff* adjustment that is larger than the
+ * 	ctx. Providing a *len_diff* adjustment that is larger than the
  * 	actual packet size (resulting in negative packet size) will in
- * 	principle not exceed the MTU, why it is not considered a
- * 	failure.  Other BPF-helpers are needed for performing the
- * 	planned size change, why the responsability for catch a negative
- * 	packet size belong in those helpers.
+ * 	principle not exceed the MTU, which is why it is not considered
+ * 	a failure.  Other BPF helpers are needed for performing the
+ * 	planned size change; therefore the responsibility for catching
+ * 	a negative packet size belongs in those helpers.
  *
  * 	Specifying *ifindex* zero means the MTU check is performed
  * 	against the current net device.  This is practical if this isn't
@@ -4040,6 +4040,7 @@ static long (*bpf_timer_cancel)(struct bpf_timer *timer) = (void *) 172;
  *
  * Returns
  * 	Address of the traced function.
+ * 	0 for kprobes placed within the function (not at the entry).
  */
 static __u64 (*bpf_get_func_ip)(void *ctx) = (void *) 173;
 
@@ -4208,13 +4209,13 @@ static long (*bpf_strncmp)(const char *s1, __u32 s1_sz, const char *s2) = (void
 /*
  * bpf_get_func_arg
  *
- * 	Get **n**-th argument (zero based) of the traced function (for tracing programs)
+ * 	Get **n**-th argument register (zero based) of the traced function (for tracing programs)
  * 	returned in **value**.
  *
  *
  * Returns
  * 	0 on success.
- * 	**-EINVAL** if n >= arguments count of traced function.
+ * 	**-EINVAL** if n >= argument register count of traced function.
  */
 static long (*bpf_get_func_arg)(void *ctx, __u32 n, __u64 *value) = (void *) 183;
 
@@ -4234,32 +4235,45 @@ static long (*bpf_get_func_ret)(void *ctx, __u64 *value) = (void *) 184;
 /*
  * bpf_get_func_arg_cnt
  *
- * 	Get number of arguments of the traced function (for tracing programs).
+ * 	Get number of registers of the traced function (for tracing programs) where
+ * 	function arguments are stored in these registers.
  *
  *
  * Returns
- * 	The number of arguments of the traced function.
+ * 	The number of argument registers of the traced function.
  */
 static long (*bpf_get_func_arg_cnt)(void *ctx) = (void *) 185;
 
 /*
  * bpf_get_retval
  *
- * 	Get the syscall's return value that will be returned to userspace.
+ * 	Get the BPF program's return value that will be returned to the upper layers.
  *
- * 	This helper is currently supported by cgroup programs only.
+ * 	This helper is currently supported by cgroup programs and only by the hooks
+ * 	where BPF program's return value is returned to the userspace via errno.
  *
  * Returns
- * 	The syscall's return value.
+ * 	The BPF program's return value.
  */
 static int (*bpf_get_retval)(void) = (void *) 186;
 
 /*
  * bpf_set_retval
  *
- * 	Set the syscall's return value that will be returned to userspace.
+ * 	Set the BPF program's return value that will be returned to the upper layers.
+ *
+ * 	This helper is currently supported by cgroup programs and only by the hooks
+ * 	where BPF program's return value is returned to the userspace via errno.
+ *
+ * 	Note that there is the following corner case where the program exports an error
+ * 	via bpf_set_retval but signals success via 'return 1':
+ *
+ * 		bpf_set_retval(-EPERM);
+ * 		return 1;
+ *
+ * 	In this case, the BPF program's return value will use helper's -EPERM. This
+ * 	still holds true for cgroup/bind{4,6} which supports extra 'return 3' success case.
  *
- * 	This helper is currently supported by cgroup programs only.
  *
  * Returns
  * 	0 on success, or a negative error in case of failure.
@@ -4606,4 +4620,46 @@ static long (*bpf_tcp_raw_check_syncookie_ipv6)(struct ipv6hdr *iph, struct tcph
  */
 static __u64 (*bpf_ktime_get_tai_ns)(void) = (void *) 208;
 
+/*
+ * bpf_user_ringbuf_drain
+ *
+ * 	Drain samples from the specified user ring buffer, and invoke
+ * 	the provided callback for each such sample:
+ *
+ * 	long (\*callback_fn)(struct bpf_dynptr \*dynptr, void \*ctx);
+ *
+ * 	If **callback_fn** returns 0, the helper will continue to try
+ * 	and drain the next sample, up to a maximum of
+ * 	BPF_MAX_USER_RINGBUF_SAMPLES samples. If the return value is 1,
+ * 	the helper will skip the rest of the samples and return. Other
+ * 	return values are not used now, and will be rejected by the
+ * 	verifier.
+ *
+ * Returns
+ * 	The number of drained samples if no error was encountered while
+ * 	draining samples, or 0 if no samples were present in the ring
+ * 	buffer. If a user-space producer was epoll-waiting on this map,
+ * 	and at least one sample was drained, they will receive an event
+ * 	notification notifying them of available space in the ring
+ * 	buffer. If the BPF_RB_NO_WAKEUP flag is passed to this
+ * 	function, no wakeup notification will be sent. If the
+ * 	BPF_RB_FORCE_WAKEUP flag is passed, a wakeup notification will
+ * 	be sent even if no sample was drained.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EBUSY** if the ring buffer is contended, and another calling
+ * 	context was concurrently draining the ring buffer.
+ *
+ * 	**-EINVAL** if user-space is not properly tracking the ring
+ * 	buffer due to the producer position not being aligned to 8
+ * 	bytes, a sample not being aligned to 8 bytes, or the producer
+ * 	position not matching the advertised length of a sample.
+ *
+ * 	**-E2BIG** if user-space has tried to publish a sample which is
+ * 	larger than the size of the ring buffer, or which cannot fit
+ * 	within a struct bpf_dynptr.
+ */
+static long (*bpf_user_ringbuf_drain)(void *map, void *callback_fn, void *ctx, __u64 flags) = (void *) 209;
+
 

src/bpf_helpers.h

@@ -160,18 +160,6 @@ bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
 }
 #endif
 
-/*
- * Helper structure used by eBPF C program
- * to describe BPF map attributes to libbpf loader
- */
-struct bpf_map_def {
-	unsigned int type;
-	unsigned int key_size;
-	unsigned int value_size;
-	unsigned int max_entries;
-	unsigned int map_flags;
-} __attribute__((deprecated("use BTF-defined maps in .maps section")));
-
 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,
 	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */

src/bpf_tracing.h

@@ -438,6 +438,113 @@ typeof(name(0)) name(unsigned long long *ctx)				    \
 static __always_inline typeof(name(0))					    \
 ____##name(unsigned long long *ctx, ##args)
 
+#ifndef ___bpf_nth2
+#define ___bpf_nth2(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13,	\
+		    _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N
+#endif
+#ifndef ___bpf_narg2
+#define ___bpf_narg2(...)	\
+	___bpf_nth2(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7,	\
+		    6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0)
+#endif
+
+#define ___bpf_treg_cnt(t) \
+	__builtin_choose_expr(sizeof(t) == 1, 1,	\
+	__builtin_choose_expr(sizeof(t) == 2, 1,	\
+	__builtin_choose_expr(sizeof(t) == 4, 1,	\
+	__builtin_choose_expr(sizeof(t) == 8, 1,	\
+	__builtin_choose_expr(sizeof(t) == 16, 2,	\
+			      (void)0)))))
+
+#define ___bpf_reg_cnt0()		(0)
+#define ___bpf_reg_cnt1(t, x)		(___bpf_reg_cnt0() + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt2(t, x, args...)	(___bpf_reg_cnt1(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt3(t, x, args...)	(___bpf_reg_cnt2(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt4(t, x, args...)	(___bpf_reg_cnt3(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt5(t, x, args...)	(___bpf_reg_cnt4(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt6(t, x, args...)	(___bpf_reg_cnt5(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt7(t, x, args...)	(___bpf_reg_cnt6(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt8(t, x, args...)	(___bpf_reg_cnt7(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt9(t, x, args...)	(___bpf_reg_cnt8(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt10(t, x, args...)	(___bpf_reg_cnt9(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt11(t, x, args...)	(___bpf_reg_cnt10(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt12(t, x, args...)	(___bpf_reg_cnt11(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt(args...)	 ___bpf_apply(___bpf_reg_cnt, ___bpf_narg2(args))(args)
+
+#define ___bpf_union_arg(t, x, n) \
+	__builtin_choose_expr(sizeof(t) == 1, ({ union { __u8 z[1]; t x; } ___t = { .z = {ctx[n]}}; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 2, ({ union { __u16 z[1]; t x; } ___t = { .z = {ctx[n]} }; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 4, ({ union { __u32 z[1]; t x; } ___t = { .z = {ctx[n]} }; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 8, ({ union { __u64 z[1]; t x; } ___t = {.z = {ctx[n]} }; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 16, ({ union { __u64 z[2]; t x; } ___t = {.z = {ctx[n], ctx[n + 1]} }; ___t.x; }), \
+			      (void)0)))))
+
+#define ___bpf_ctx_arg0(n, args...)
+#define ___bpf_ctx_arg1(n, t, x)		, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt1(t, x))
+#define ___bpf_ctx_arg2(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt2(t, x, args)) ___bpf_ctx_arg1(n, args)
+#define ___bpf_ctx_arg3(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt3(t, x, args)) ___bpf_ctx_arg2(n, args)
+#define ___bpf_ctx_arg4(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt4(t, x, args)) ___bpf_ctx_arg3(n, args)
+#define ___bpf_ctx_arg5(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt5(t, x, args)) ___bpf_ctx_arg4(n, args)
+#define ___bpf_ctx_arg6(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt6(t, x, args)) ___bpf_ctx_arg5(n, args)
+#define ___bpf_ctx_arg7(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt7(t, x, args)) ___bpf_ctx_arg6(n, args)
+#define ___bpf_ctx_arg8(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt8(t, x, args)) ___bpf_ctx_arg7(n, args)
+#define ___bpf_ctx_arg9(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt9(t, x, args)) ___bpf_ctx_arg8(n, args)
+#define ___bpf_ctx_arg10(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt10(t, x, args)) ___bpf_ctx_arg9(n, args)
+#define ___bpf_ctx_arg11(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt11(t, x, args)) ___bpf_ctx_arg10(n, args)
+#define ___bpf_ctx_arg12(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt12(t, x, args)) ___bpf_ctx_arg11(n, args)
+#define ___bpf_ctx_arg(args...)	___bpf_apply(___bpf_ctx_arg, ___bpf_narg2(args))(___bpf_reg_cnt(args), args)
+
+#define ___bpf_ctx_decl0()
+#define ___bpf_ctx_decl1(t, x)			, t x
+#define ___bpf_ctx_decl2(t, x, args...)		, t x ___bpf_ctx_decl1(args)
+#define ___bpf_ctx_decl3(t, x, args...)		, t x ___bpf_ctx_decl2(args)
+#define ___bpf_ctx_decl4(t, x, args...)		, t x ___bpf_ctx_decl3(args)
+#define ___bpf_ctx_decl5(t, x, args...)		, t x ___bpf_ctx_decl4(args)
+#define ___bpf_ctx_decl6(t, x, args...)		, t x ___bpf_ctx_decl5(args)
+#define ___bpf_ctx_decl7(t, x, args...)		, t x ___bpf_ctx_decl6(args)
+#define ___bpf_ctx_decl8(t, x, args...)		, t x ___bpf_ctx_decl7(args)
+#define ___bpf_ctx_decl9(t, x, args...)		, t x ___bpf_ctx_decl8(args)
+#define ___bpf_ctx_decl10(t, x, args...)	, t x ___bpf_ctx_decl9(args)
+#define ___bpf_ctx_decl11(t, x, args...)	, t x ___bpf_ctx_decl10(args)
+#define ___bpf_ctx_decl12(t, x, args...)	, t x ___bpf_ctx_decl11(args)
+#define ___bpf_ctx_decl(args...)	___bpf_apply(___bpf_ctx_decl, ___bpf_narg2(args))(args)
+
+/*
+ * BPF_PROG2 is an enhanced version of BPF_PROG in order to handle struct
+ * arguments. Since each struct argument might take one or two u64 values
+ * in the trampoline stack, argument type size is needed to place proper number
+ * of u64 values for each argument. Therefore, BPF_PROG2 has different
+ * syntax from BPF_PROG. For example, for the following BPF_PROG syntax:
+ *
+ *   int BPF_PROG(test2, int a, int b) { ... }
+ *
+ * the corresponding BPF_PROG2 syntax is:
+ *
+ *   int BPF_PROG2(test2, int, a, int, b) { ... }
+ *
+ * where type and the corresponding argument name are separated by comma.
+ *
+ * Use BPF_PROG2 macro if one of the arguments might be a struct/union larger
+ * than 8 bytes:
+ *
+ *   int BPF_PROG2(test_struct_arg, struct bpf_testmod_struct_arg_1, a, int, b,
+ *		   int, c, int, d, struct bpf_testmod_struct_arg_2, e, int, ret)
+ *   {
+ *        // access a, b, c, d, e, and ret directly
+ *        ...
+ *   }
+ */
+#define BPF_PROG2(name, args...)						\
+name(unsigned long long *ctx);							\
+static __always_inline typeof(name(0))						\
+____##name(unsigned long long *ctx ___bpf_ctx_decl(args));			\
+typeof(name(0)) name(unsigned long long *ctx)					\
+{										\
+	return ____##name(ctx ___bpf_ctx_arg(args));				\
+}										\
+static __always_inline typeof(name(0))						\
+____##name(unsigned long long *ctx ___bpf_ctx_decl(args))
+
 struct pt_regs;
 
 #define ___bpf_kprobe_args0()           ctx

src/btf.c

@@ -4642,20 +4642,17 @@ static int btf_dedup_remap_types(struct btf_dedup *d)
  */
 struct btf *btf__load_vmlinux_btf(void)
 {
-	struct {
-		const char *path_fmt;
-		bool raw_btf;
-	} locations[] = {
+	const char *locations[] = {
 		/* try canonical vmlinux BTF through sysfs first */
-		{ "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
-		/* fall back to trying to find vmlinux ELF on disk otherwise */
-		{ "/boot/vmlinux-%1$s" },
-		{ "/lib/modules/%1$s/vmlinux-%1$s" },
-		{ "/lib/modules/%1$s/build/vmlinux" },
-		{ "/usr/lib/modules/%1$s/kernel/vmlinux" },
-		{ "/usr/lib/debug/boot/vmlinux-%1$s" },
-		{ "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
-		{ "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
+		"/sys/kernel/btf/vmlinux",
+		/* fall back to trying to find vmlinux on disk otherwise */
+		"/boot/vmlinux-%1$s",
+		"/lib/modules/%1$s/vmlinux-%1$s",
+		"/lib/modules/%1$s/build/vmlinux",
+		"/usr/lib/modules/%1$s/kernel/vmlinux",
+		"/usr/lib/debug/boot/vmlinux-%1$s",
+		"/usr/lib/debug/boot/vmlinux-%1$s.debug",
+		"/usr/lib/debug/lib/modules/%1$s/vmlinux",
 	};
 	char path[PATH_MAX + 1];
 	struct utsname buf;
@@ -4665,15 +4662,12 @@ struct btf *btf__load_vmlinux_btf(void)
 	uname(&buf);
 
 	for (i = 0; i < ARRAY_SIZE(locations); i++) {
-		snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
+		snprintf(path, PATH_MAX, locations[i], buf.release);
 
-		if (access(path, R_OK))
+		if (faccessat(AT_FDCWD, path, R_OK, AT_EACCESS))
 			continue;
 
-		if (locations[i].raw_btf)
-			btf = btf__parse_raw(path);
-		else
-			btf = btf__parse_elf(path, NULL);
+		btf = btf__parse(path, NULL);
 		err = libbpf_get_error(btf);
 		pr_debug("loading kernel BTF '%s': %d\n", path, err);
 		if (err)

src/btf.h

@@ -486,6 +486,8 @@ static inline struct btf_enum *btf_enum(const struct btf_type *t)
 	return (struct btf_enum *)(t + 1);
 }
 
+struct btf_enum64;
+
 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
 {
 	return (struct btf_enum64 *)(t + 1);
@@ -493,7 +495,28 @@ static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
 
 static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
 {
-	return ((__u64)e->val_hi32 << 32) | e->val_lo32;
+	/* struct btf_enum64 is introduced in Linux 6.0, which is very
+	 * bleeding-edge. Here we are avoiding relying on struct btf_enum64
+	 * definition coming from kernel UAPI headers to support wider range
+	 * of system-wide kernel headers.
+	 *
+	 * Given this header can be also included from C++ applications, that
+	 * further restricts C tricks we can use (like using compatible
+	 * anonymous struct). So just treat struct btf_enum64 as
+	 * a three-element array of u32 and access second (lo32) and third
+	 * (hi32) elements directly.
+	 *
+	 * For reference, here is a struct btf_enum64 definition:
+	 *
+	 * const struct btf_enum64 {
+	 *	__u32	name_off;
+	 *	__u32	val_lo32;
+	 *	__u32	val_hi32;
+	 * };
+	 */
+	const __u32 *e64 = (const __u32 *)e;
+
+	return ((__u64)e64[2] << 32) | e64[1];
 }
 
 static inline struct btf_member *btf_members(const struct btf_type *t)

src/btf_dump.c

@@ -2385,7 +2385,7 @@ int btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
 	d->typed_dump->indent_lvl = OPTS_GET(opts, indent_level, 0);
 
 	/* default indent string is a tab */
-	if (!opts->indent_str)
+	if (!OPTS_GET(opts, indent_str, NULL))
 		d->typed_dump->indent_str[0] = '\t';
 	else
 		libbpf_strlcpy(d->typed_dump->indent_str, opts->indent_str,

src/libbpf.c

@@ -163,6 +163,7 @@ static const char * const map_type_name[] = {
 	[BPF_MAP_TYPE_INODE_STORAGE]		= "inode_storage",
 	[BPF_MAP_TYPE_TASK_STORAGE]		= "task_storage",
 	[BPF_MAP_TYPE_BLOOM_FILTER]		= "bloom_filter",
+	[BPF_MAP_TYPE_USER_RINGBUF]             = "user_ringbuf",
 };
 
 static const char * const prog_type_name[] = {
@@ -883,7 +884,7 @@ __u32 get_kernel_version(void)
 	__u32 major, minor, patch;
 	struct utsname info;
 
-	if (access(ubuntu_kver_file, R_OK) == 0) {
+	if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) == 0) {
 		FILE *f;
 
 		f = fopen(ubuntu_kver_file, "r");
@@ -2096,19 +2097,30 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf,
 	return true;
 }
 
+static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name)
+{
+	int len;
+
+	len = snprintf(buf, buf_sz, "%s/%s", path, name);
+	if (len < 0)
+		return -EINVAL;
+	if (len >= buf_sz)
+		return -ENAMETOOLONG;
+
+	return 0;
+}
+
 static int build_map_pin_path(struct bpf_map *map, const char *path)
 {
 	char buf[PATH_MAX];
-	int len;
+	int err;
 
 	if (!path)
 		path = "/sys/fs/bpf";
 
-	len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
-	if (len < 0)
-		return -EINVAL;
-	else if (len >= PATH_MAX)
-		return -ENAMETOOLONG;
+	err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map));
+	if (err)
+		return err;
 
 	return bpf_map__set_pin_path(map, buf);
 }
@@ -2372,6 +2384,12 @@ static size_t adjust_ringbuf_sz(size_t sz)
 	return sz;
 }
 
+static bool map_is_ringbuf(const struct bpf_map *map)
+{
+	return map->def.type == BPF_MAP_TYPE_RINGBUF ||
+	       map->def.type == BPF_MAP_TYPE_USER_RINGBUF;
+}
+
 static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def)
 {
 	map->def.type = def->map_type;
@@ -2386,7 +2404,7 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def
 	map->btf_value_type_id = def->value_type_id;
 
 	/* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */
-	if (map->def.type == BPF_MAP_TYPE_RINGBUF)
+	if (map_is_ringbuf(map))
 		map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries);
 
 	if (def->parts & MAP_DEF_MAP_TYPE)
@@ -4369,7 +4387,7 @@ int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries)
 	map->def.max_entries = max_entries;
 
 	/* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */
-	if (map->def.type == BPF_MAP_TYPE_RINGBUF)
+	if (map_is_ringbuf(map))
 		map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries);
 
 	return 0;
@@ -7961,17 +7979,9 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
 			continue;
 
 		if (path) {
-			int len;
-
-			len = snprintf(buf, PATH_MAX, "%s/%s", path,
-				       bpf_map__name(map));
-			if (len < 0) {
-				err = -EINVAL;
+			err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map));
+			if (err)
 				goto err_unpin_maps;
-			} else if (len >= PATH_MAX) {
-				err = -ENAMETOOLONG;
-				goto err_unpin_maps;
-			}
 			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
@@ -8009,14 +8019,9 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 		char buf[PATH_MAX];
 
 		if (path) {
-			int len;
-
-			len = snprintf(buf, PATH_MAX, "%s/%s", path,
-				       bpf_map__name(map));
-			if (len < 0)
-				return libbpf_err(-EINVAL);
-			else if (len >= PATH_MAX)
-				return libbpf_err(-ENAMETOOLONG);
+			err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map));
+			if (err)
+				return libbpf_err(err);
 			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
@@ -8034,6 +8039,7 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 {
 	struct bpf_program *prog;
+	char buf[PATH_MAX];
 	int err;
 
 	if (!obj)
@@ -8045,17 +8051,9 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 	}
 
 	bpf_object__for_each_program(prog, obj) {
-		char buf[PATH_MAX];
-		int len;
-
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0) {
-			err = -EINVAL;
+		err = pathname_concat(buf, sizeof(buf), path, prog->name);
+		if (err)
 			goto err_unpin_programs;
-		} else if (len >= PATH_MAX) {
-			err = -ENAMETOOLONG;
-			goto err_unpin_programs;
-		}
 
 		err = bpf_program__pin(prog, buf);
 		if (err)
@@ -8066,13 +8064,7 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 
 err_unpin_programs:
 	while ((prog = bpf_object__prev_program(obj, prog))) {
-		char buf[PATH_MAX];
-		int len;
-
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0)
-			continue;
-		else if (len >= PATH_MAX)
+		if (pathname_concat(buf, sizeof(buf), path, prog->name))
 			continue;
 
 		bpf_program__unpin(prog, buf);
@@ -8091,13 +8083,10 @@ int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
 
 	bpf_object__for_each_program(prog, obj) {
 		char buf[PATH_MAX];
-		int len;
 
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0)
-			return libbpf_err(-EINVAL);
-		else if (len >= PATH_MAX)
-			return libbpf_err(-ENAMETOOLONG);
+		err = pathname_concat(buf, sizeof(buf), path, prog->name);
+		if (err)
+			return libbpf_err(err);
 
 		err = bpf_program__unpin(prog, buf);
 		if (err)
@@ -9084,11 +9073,15 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac
 	int err = 0;
 
 	/* BPF program's BTF ID */
-	if (attach_prog_fd) {
+	if (prog->type == BPF_PROG_TYPE_EXT || attach_prog_fd) {
+		if (!attach_prog_fd) {
+			pr_warn("prog '%s': attach program FD is not set\n", prog->name);
+			return -EINVAL;
+		}
 		err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd);
 		if (err < 0) {
-			pr_warn("failed to find BPF program (FD %d) BTF ID for '%s': %d\n",
-				 attach_prog_fd, attach_name, err);
+			pr_warn("prog '%s': failed to find BPF program (FD %d) BTF ID for '%s': %d\n",
+				 prog->name, attach_prog_fd, attach_name, err);
 			return err;
 		}
 		*btf_obj_fd = 0;
@@ -9105,7 +9098,8 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac
 		err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id);
 	}
 	if (err) {
-		pr_warn("failed to find kernel BTF type ID of '%s': %d\n", attach_name, err);
+		pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n",
+			prog->name, attach_name, err);
 		return err;
 	}
 	return 0;
@@ -9910,7 +9904,7 @@ static bool use_debugfs(void)
 	static int has_debugfs = -1;
 
 	if (has_debugfs < 0)
-		has_debugfs = access(DEBUGFS, F_OK) == 0;
+		has_debugfs = faccessat(AT_FDCWD, DEBUGFS, F_OK, AT_EACCESS) == 0;
 
 	return has_debugfs == 1;
 }
@@ -10727,7 +10721,7 @@ static int resolve_full_path(const char *file, char *result, size_t result_sz)
 				continue;
 			snprintf(result, result_sz, "%.*s/%s", seg_len, s, file);
 			/* ensure it has required permissions */
-			if (access(result, perm) < 0)
+			if (faccessat(AT_FDCWD, result, perm, AT_EACCESS) < 0)
 				continue;
 			pr_debug("resolved '%s' to '%s'\n", file, result);
 			return 0;

src/libbpf.h

@@ -118,7 +118,9 @@ struct bpf_object_open_opts {
 	 * auto-pinned to that path on load; defaults to "/sys/fs/bpf".
 	 */
 	const char *pin_root_path;
-	long :0;
+
+	__u32 :32; /* stub out now removed attach_prog_fd */
+
 	/* Additional kernel config content that augments and overrides
 	 * system Kconfig for CONFIG_xxx externs.
 	 */
@@ -1011,6 +1013,7 @@ LIBBPF_API int bpf_tc_query(const struct bpf_tc_hook *hook,
 
 /* Ring buffer APIs */
 struct ring_buffer;
+struct user_ring_buffer;
 
 typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size);
 
@@ -1030,6 +1033,112 @@ LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
 LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
 LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
 
+struct user_ring_buffer_opts {
+	size_t sz; /* size of this struct, for forward/backward compatibility */
+};
+
+#define user_ring_buffer_opts__last_field sz
+
+/* @brief **user_ring_buffer__new()** creates a new instance of a user ring
+ * buffer.
+ *
+ * @param map_fd A file descriptor to a BPF_MAP_TYPE_USER_RINGBUF map.
+ * @param opts Options for how the ring buffer should be created.
+ * @return A user ring buffer on success; NULL and errno being set on a
+ * failure.
+ */
+LIBBPF_API struct user_ring_buffer *
+user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts);
+
+/* @brief **user_ring_buffer__reserve()** reserves a pointer to a sample in the
+ * user ring buffer.
+ * @param rb A pointer to a user ring buffer.
+ * @param size The size of the sample, in bytes.
+ * @return A pointer to an 8-byte aligned reserved region of the user ring
+ * buffer; NULL, and errno being set if a sample could not be reserved.
+ *
+ * This function is *not* thread safe, and callers must synchronize accessing
+ * this function if there are multiple producers.  If a size is requested that
+ * is larger than the size of the entire ring buffer, errno will be set to
+ * E2BIG and NULL is returned. If the ring buffer could accommodate the size,
+ * but currently does not have enough space, errno is set to ENOSPC and NULL is
+ * returned.
+ *
+ * After initializing the sample, callers must invoke
+ * **user_ring_buffer__submit()** to post the sample to the kernel. Otherwise,
+ * the sample must be freed with **user_ring_buffer__discard()**.
+ */
+LIBBPF_API void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
+
+/* @brief **user_ring_buffer__reserve_blocking()** reserves a record in the
+ * ring buffer, possibly blocking for up to @timeout_ms until a sample becomes
+ * available.
+ * @param rb The user ring buffer.
+ * @param size The size of the sample, in bytes.
+ * @param timeout_ms The amount of time, in milliseconds, for which the caller
+ * should block when waiting for a sample. -1 causes the caller to block
+ * indefinitely.
+ * @return A pointer to an 8-byte aligned reserved region of the user ring
+ * buffer; NULL, and errno being set if a sample could not be reserved.
+ *
+ * This function is *not* thread safe, and callers must synchronize
+ * accessing this function if there are multiple producers
+ *
+ * If **timeout_ms** is -1, the function will block indefinitely until a sample
+ * becomes available. Otherwise, **timeout_ms** must be non-negative, or errno
+ * is set to EINVAL, and NULL is returned. If **timeout_ms** is 0, no blocking
+ * will occur and the function will return immediately after attempting to
+ * reserve a sample.
+ *
+ * If **size** is larger than the size of the entire ring buffer, errno is set
+ * to E2BIG and NULL is returned. If the ring buffer could accommodate
+ * **size**, but currently does not have enough space, the caller will block
+ * until at most **timeout_ms** has elapsed. If insufficient space is available
+ * at that time, errno is set to ENOSPC, and NULL is returned.
+ *
+ * The kernel guarantees that it will wake up this thread to check if
+ * sufficient space is available in the ring buffer at least once per
+ * invocation of the **bpf_ringbuf_drain()** helper function, provided that at
+ * least one sample is consumed, and the BPF program did not invoke the
+ * function with BPF_RB_NO_WAKEUP. A wakeup may occur sooner than that, but the
+ * kernel does not guarantee this. If the helper function is invoked with
+ * BPF_RB_FORCE_WAKEUP, a wakeup event will be sent even if no sample is
+ * consumed.
+ *
+ * When a sample of size **size** is found within **timeout_ms**, a pointer to
+ * the sample is returned. After initializing the sample, callers must invoke
+ * **user_ring_buffer__submit()** to post the sample to the ring buffer.
+ * Otherwise, the sample must be freed with **user_ring_buffer__discard()**.
+ */
+LIBBPF_API void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
+						    __u32 size,
+						    int timeout_ms);
+
+/* @brief **user_ring_buffer__submit()** submits a previously reserved sample
+ * into the ring buffer.
+ * @param rb The user ring buffer.
+ * @param sample A reserved sample.
+ *
+ * It is not necessary to synchronize amongst multiple producers when invoking
+ * this function.
+ */
+LIBBPF_API void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
+
+/* @brief **user_ring_buffer__discard()** discards a previously reserved sample.
+ * @param rb The user ring buffer.
+ * @param sample A reserved sample.
+ *
+ * It is not necessary to synchronize amongst multiple producers when invoking
+ * this function.
+ */
+LIBBPF_API void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample);
+
+/* @brief **user_ring_buffer__free()** frees a ring buffer that was previously
+ * created with **user_ring_buffer__new()**.
+ * @param rb The user ring buffer being freed.
+ */
+LIBBPF_API void user_ring_buffer__free(struct user_ring_buffer *rb);
+
 /* Perf buffer APIs */
 struct perf_buffer;
 

src/libbpf.map

@@ -368,3 +368,13 @@ LIBBPF_1.0.0 {
 		libbpf_bpf_prog_type_str;
 		perf_buffer__buffer;
 };
+
+LIBBPF_1.1.0 {
+	global:
+		user_ring_buffer__discard;
+		user_ring_buffer__free;
+		user_ring_buffer__new;
+		user_ring_buffer__reserve;
+		user_ring_buffer__reserve_blocking;
+		user_ring_buffer__submit;
+} LIBBPF_1.0.0;

src/libbpf_probes.c

@@ -231,6 +231,7 @@ static int probe_map_create(enum bpf_map_type map_type)
 			return btf_fd;
 		break;
 	case BPF_MAP_TYPE_RINGBUF:
+	case BPF_MAP_TYPE_USER_RINGBUF:
 		key_size = 0;
 		value_size = 0;
 		max_entries = 4096;

src/libbpf_version.h

@@ -4,6 +4,6 @@
 #define __LIBBPF_VERSION_H
 
 #define LIBBPF_MAJOR_VERSION 1
-#define LIBBPF_MINOR_VERSION 0
+#define LIBBPF_MINOR_VERSION 1
 
 #endif /* __LIBBPF_VERSION_H */

src/ringbuf.c

@@ -16,6 +16,7 @@
 #include <asm/barrier.h>
 #include <sys/mman.h>
 #include <sys/epoll.h>
+#include <time.h>
 
 #include "libbpf.h"
 #include "libbpf_internal.h"
@@ -39,6 +40,23 @@ struct ring_buffer {
 	int ring_cnt;
 };
 
+struct user_ring_buffer {
+	struct epoll_event event;
+	unsigned long *consumer_pos;
+	unsigned long *producer_pos;
+	void *data;
+	unsigned long mask;
+	size_t page_size;
+	int map_fd;
+	int epoll_fd;
+};
+
+/* 8-byte ring buffer header structure */
+struct ringbuf_hdr {
+	__u32 len;
+	__u32 pad;
+};
+
 static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r)
 {
 	if (r->consumer_pos) {
@@ -300,3 +318,256 @@ int ring_buffer__epoll_fd(const struct ring_buffer *rb)
 {
 	return rb->epoll_fd;
 }
+
+static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
+{
+	if (rb->consumer_pos) {
+		munmap(rb->consumer_pos, rb->page_size);
+		rb->consumer_pos = NULL;
+	}
+	if (rb->producer_pos) {
+		munmap(rb->producer_pos, rb->page_size + 2 * (rb->mask + 1));
+		rb->producer_pos = NULL;
+	}
+}
+
+void user_ring_buffer__free(struct user_ring_buffer *rb)
+{
+	if (!rb)
+		return;
+
+	user_ringbuf_unmap_ring(rb);
+
+	if (rb->epoll_fd >= 0)
+		close(rb->epoll_fd);
+
+	free(rb);
+}
+
+static int user_ringbuf_map(struct user_ring_buffer *rb, int map_fd)
+{
+	struct bpf_map_info info;
+	__u32 len = sizeof(info);
+	void *tmp;
+	struct epoll_event *rb_epoll;
+	int err;
+
+	memset(&info, 0, sizeof(info));
+
+	err = bpf_obj_get_info_by_fd(map_fd, &info, &len);
+	if (err) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to get map info for fd=%d: %d\n", map_fd, err);
+		return err;
+	}
+
+	if (info.type != BPF_MAP_TYPE_USER_RINGBUF) {
+		pr_warn("user ringbuf: map fd=%d is not BPF_MAP_TYPE_USER_RINGBUF\n", map_fd);
+		return -EINVAL;
+	}
+
+	rb->map_fd = map_fd;
+	rb->mask = info.max_entries - 1;
+
+	/* Map read-only consumer page */
+	tmp = mmap(NULL, rb->page_size, PROT_READ, MAP_SHARED, map_fd, 0);
+	if (tmp == MAP_FAILED) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to mmap consumer page for map fd=%d: %d\n",
+			map_fd, err);
+		return err;
+	}
+	rb->consumer_pos = tmp;
+
+	/* Map read-write the producer page and data pages. We map the data
+	 * region as twice the total size of the ring buffer to allow the
+	 * simple reading and writing of samples that wrap around the end of
+	 * the buffer.  See the kernel implementation for details.
+	 */
+	tmp = mmap(NULL, rb->page_size + 2 * info.max_entries,
+		   PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, rb->page_size);
+	if (tmp == MAP_FAILED) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to mmap data pages for map fd=%d: %d\n",
+			map_fd, err);
+		return err;
+	}
+
+	rb->producer_pos = tmp;
+	rb->data = tmp + rb->page_size;
+
+	rb_epoll = &rb->event;
+	rb_epoll->events = EPOLLOUT;
+	if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, rb_epoll) < 0) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to epoll add map fd=%d: %d\n", map_fd, err);
+		return err;
+	}
+
+	return 0;
+}
+
+struct user_ring_buffer *
+user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts)
+{
+	struct user_ring_buffer *rb;
+	int err;
+
+	if (!OPTS_VALID(opts, user_ring_buffer_opts))
+		return errno = EINVAL, NULL;
+
+	rb = calloc(1, sizeof(*rb));
+	if (!rb)
+		return errno = ENOMEM, NULL;
+
+	rb->page_size = getpagesize();
+
+	rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+	if (rb->epoll_fd < 0) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to create epoll instance: %d\n", err);
+		goto err_out;
+	}
+
+	err = user_ringbuf_map(rb, map_fd);
+	if (err)
+		goto err_out;
+
+	return rb;
+
+err_out:
+	user_ring_buffer__free(rb);
+	return errno = -err, NULL;
+}
+
+static void user_ringbuf_commit(struct user_ring_buffer *rb, void *sample, bool discard)
+{
+	__u32 new_len;
+	struct ringbuf_hdr *hdr;
+	uintptr_t hdr_offset;
+
+	hdr_offset = rb->mask + 1 + (sample - rb->data) - BPF_RINGBUF_HDR_SZ;
+	hdr = rb->data + (hdr_offset & rb->mask);
+
+	new_len = hdr->len & ~BPF_RINGBUF_BUSY_BIT;
+	if (discard)
+		new_len |= BPF_RINGBUF_DISCARD_BIT;
+
+	/* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in
+	 * the kernel.
+	 */
+	__atomic_exchange_n(&hdr->len, new_len, __ATOMIC_ACQ_REL);
+}
+
+void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample)
+{
+	user_ringbuf_commit(rb, sample, true);
+}
+
+void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample)
+{
+	user_ringbuf_commit(rb, sample, false);
+}
+
+void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size)
+{
+	__u32 avail_size, total_size, max_size;
+	/* 64-bit to avoid overflow in case of extreme application behavior */
+	__u64 cons_pos, prod_pos;
+	struct ringbuf_hdr *hdr;
+
+	/* Synchronizes with smp_store_release() in __bpf_user_ringbuf_peek() in
+	 * the kernel.
+	 */
+	cons_pos = smp_load_acquire(rb->consumer_pos);
+	/* Synchronizes with smp_store_release() in user_ringbuf_commit() */
+	prod_pos = smp_load_acquire(rb->producer_pos);
+
+	max_size = rb->mask + 1;
+	avail_size = max_size - (prod_pos - cons_pos);
+	/* Round up total size to a multiple of 8. */
+	total_size = (size + BPF_RINGBUF_HDR_SZ + 7) / 8 * 8;
+
+	if (total_size > max_size)
+		return errno = E2BIG, NULL;
+
+	if (avail_size < total_size)
+		return errno = ENOSPC, NULL;
+
+	hdr = rb->data + (prod_pos & rb->mask);
+	hdr->len = size | BPF_RINGBUF_BUSY_BIT;
+	hdr->pad = 0;
+
+	/* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in
+	 * the kernel.
+	 */
+	smp_store_release(rb->producer_pos, prod_pos + total_size);
+
+	return (void *)rb->data + ((prod_pos + BPF_RINGBUF_HDR_SZ) & rb->mask);
+}
+
+static __u64 ns_elapsed_timespec(const struct timespec *start, const struct timespec *end)
+{
+	__u64 start_ns, end_ns, ns_per_s = 1000000000;
+
+	start_ns = (__u64)start->tv_sec * ns_per_s + start->tv_nsec;
+	end_ns = (__u64)end->tv_sec * ns_per_s + end->tv_nsec;
+
+	return end_ns - start_ns;
+}
+
+void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms)
+{
+	void *sample;
+	int err, ms_remaining = timeout_ms;
+	struct timespec start;
+
+	if (timeout_ms < 0 && timeout_ms != -1)
+		return errno = EINVAL, NULL;
+
+	if (timeout_ms != -1) {
+		err = clock_gettime(CLOCK_MONOTONIC, &start);
+		if (err)
+			return NULL;
+	}
+
+	do {
+		int cnt, ms_elapsed;
+		struct timespec curr;
+		__u64 ns_per_ms = 1000000;
+
+		sample = user_ring_buffer__reserve(rb, size);
+		if (sample)
+			return sample;
+		else if (errno != ENOSPC)
+			return NULL;
+
+		/* The kernel guarantees at least one event notification
+		 * delivery whenever at least one sample is drained from the
+		 * ring buffer in an invocation to bpf_ringbuf_drain(). Other
+		 * additional events may be delivered at any time, but only one
+		 * event is guaranteed per bpf_ringbuf_drain() invocation,
+		 * provided that a sample is drained, and the BPF program did
+		 * not pass BPF_RB_NO_WAKEUP to bpf_ringbuf_drain(). If
+		 * BPF_RB_FORCE_WAKEUP is passed to bpf_ringbuf_drain(), a
+		 * wakeup event will be delivered even if no samples are
+		 * drained.
+		 */
+		cnt = epoll_wait(rb->epoll_fd, &rb->event, 1, ms_remaining);
+		if (cnt < 0)
+			return NULL;
+
+		if (timeout_ms == -1)
+			continue;
+
+		err = clock_gettime(CLOCK_MONOTONIC, &curr);
+		if (err)
+			return NULL;
+
+		ms_elapsed = ns_elapsed_timespec(&start, &curr) / ns_per_ms;
+		ms_remaining = timeout_ms - ms_elapsed;
+	} while (ms_remaining > 0);
+
+	/* Try one more time to reserve a sample after the specified timeout has elapsed. */
+	return user_ring_buffer__reserve(rb, size);
+}

src/skel_internal.h

@@ -251,6 +251,29 @@ static inline int skel_map_update_elem(int fd, const void *key,
 	return skel_sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, attr_sz);
 }
 
+static inline int skel_map_delete_elem(int fd, const void *key)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = (long)key;
+
+	return skel_sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
+}
+
+static inline int skel_map_get_fd_by_id(__u32 id)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_id = id;
+
+	return skel_sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz);
+}
+
 static inline int skel_raw_tracepoint_open(const char *name, int prog_fd)
 {
 	const size_t attr_sz = offsetofend(union bpf_attr, raw_tracepoint.prog_fd);

src/usdt.c

@@ -282,7 +282,7 @@ struct usdt_manager *usdt_manager_new(struct bpf_object *obj)
 	 * If this is not supported, USDTs with semaphores will not be supported.
 	 * Added in: a6ca88b241d5 ("trace_uprobe: support reference counter in fd-based uprobe")
 	 */
-	man->has_sema_refcnt = access(ref_ctr_sysfs_path, F_OK) == 0;
+	man->has_sema_refcnt = faccessat(AT_FDCWD, ref_ctr_sysfs_path, F_OK, AT_EACCESS) == 0;
 
 	return man;
 }