C Coding Style - eBPF

[geyslan]

When it comes to a Go project, this theme seems irrelevant, since the language tooling almost forces its idioms and formatting. However, KubeArmor has, at its heart, eBPF code programmed in C.

On the other hand, a code in C, to be read and accepted by the compiler, doesn't need to follow any idioms, formatting, much less style. It just needs to be syntactically correct [1].

Such freedom can be the birthplace of chaos.

Since KubeArmor's C code base is growing rapidly, I start this discussion by bringing some references, with the purpose of defining and adopting a coding style for the C language that can be practical, that can avoid errors and that it can maintain hygienic our work flow.

As a base reference, I propose a mix of the style used in the Linux Kernel [2] and the style used by the FreeBSD Kernel [3].

Because of the aforementioned freedom, both styles set a lot of rules in order to keep the house in order. So, there are many instructions to be memorized and followed.

To avoid the hassle of constantly worrying about formatting, which can get us off the rails, I suggest using the clang-format tool [4] that can import a list of predefined rules, automatically formatting the code for us.

[1] - https://www.ioccc.org/2020/carlini/prog.c
[2] - https://www.kernel.org/doc/html/latest/process/coding-style.html
[3] - https://www.freebsd.org/cgi/man.cgi?query=style&sektion=9
[4] - https://clang.llvm.org/docs/ClangFormat.html

Further reading:

Kroah-Hartman, Greg, Documentation/CodingStyle and Beyond, https://landley.net/kdocs/ols/2002/ols2002-pages-250-259.pdf

[geyslan]

These are two already merged files using the proposed .clang-format with mixing rules:

https://raw.githubusercontent.com/kubearmor/KubeArmor/event-auditor/KubeArmor/BPF/ka_ea_process.bpf.c

https://raw.githubusercontent.com/kubearmor/KubeArmor/event-auditor/KubeArmor/BPF/common.bpf.h

Of course we can discuss the rules as nothing is defined yet.

.clang-format

# SPDX-License-Identifier: GPL-2.0
#
# clang-format configuration file. Intended for clang-format >= 4.
#
# For more information, see:
#
#   Documentation/process/clang-format.rst
#   https://clang.llvm.org/docs/ClangFormat.html
#   https://clang.llvm.org/docs/ClangFormatStyleOptions.html
#

#
# Based on:
# https://github.com/torvalds/linux/blob/ec681c53f8d2d0ee362ff67f5b98dd8263c15002/.clang-format
#

---
AccessModifierOffset: -4
AlignAfterOpenBracket: Align
#AlignArrayOfStructures: Right # Unknown to clang-format-12.0.1
AlignConsecutiveAssignments: AcrossComments
AlignConsecutiveDeclarations: AcrossComments
AlignConsecutiveMacros: AcrossComments
AlignEscapedNewlines: Left # Unknown to clang-format-4.0
AlignOperands: true
AlignTrailingComments: true
AllowAllParametersOfDeclarationOnNextLine: false
AllowShortBlocksOnASingleLine: false
AllowShortCaseLabelsOnASingleLine: false
AllowShortFunctionsOnASingleLine: None
AllowShortIfStatementsOnASingleLine: false
AllowShortLoopsOnASingleLine: false
AlwaysBreakAfterDefinitionReturnType: None
AlwaysBreakAfterReturnType: TopLevelDefinitions
AlwaysBreakBeforeMultilineStrings: false
AlwaysBreakTemplateDeclarations: false
BinPackArguments: true
BinPackParameters: true
BraceWrapping:
  AfterClass: false
  AfterControlStatement: false
  AfterEnum: false
  AfterFunction: true
  AfterNamespace: true
  AfterObjCDeclaration: false
  AfterStruct: false
  AfterUnion: false
  #AfterExternBlock: false # Unknown to clang-format-5.0
  BeforeCatch: false
  BeforeElse: false
  IndentBraces: false
  #SplitEmptyFunction: true # Unknown to clang-format-4.0
  #SplitEmptyRecord: true # Unknown to clang-format-4.0
  #SplitEmptyNamespace: true # Unknown to clang-format-4.0
BreakBeforeBinaryOperators: None
BreakBeforeBraces: Custom
#BreakBeforeInheritanceComma: false # Unknown to clang-format-4.0
BreakBeforeTernaryOperators: false
BreakConstructorInitializersBeforeComma: false
#BreakConstructorInitializers: BeforeComma # Unknown to clang-format-4.0
BreakAfterJavaFieldAnnotations: false
BreakStringLiterals: false
ColumnLimit: 80
CommentPragmas: '^ IWYU pragma:'
#CompactNamespaces: false # Unknown to clang-format-4.0
ConstructorInitializerAllOnOneLineOrOnePerLine: false
ConstructorInitializerIndentWidth: 8
ContinuationIndentWidth: 8
Cpp11BracedListStyle: false
DerivePointerAlignment: false
DisableFormat: false
ExperimentalAutoDetectBinPacking: false
#FixNamespaceComments: false # Unknown to clang-format-4.0

# Taken from:
#   git grep -h '^#define [^[:space:]]*for_each[^[:space:]]*(' include/ \
#   | sed "s,^#define \([^[:space:]]*for_each[^[:space:]]*\)(.*$,  - '\1'," \
#   | sort | uniq
ForEachMacros:
  - 'apei_estatus_for_each_section'
  - 'ata_for_each_dev'
  - 'ata_for_each_link'
  - '__ata_qc_for_each'
  - 'ata_qc_for_each'
  - 'ata_qc_for_each_raw'
  - 'ata_qc_for_each_with_internal'
  - 'ax25_for_each'
  - 'ax25_uid_for_each'
  - '__bio_for_each_bvec'
  - 'bio_for_each_bvec'
  - 'bio_for_each_bvec_all'
  - 'bio_for_each_integrity_vec'
  - '__bio_for_each_segment'
  - 'bio_for_each_segment'
  - 'bio_for_each_segment_all'
  - 'bio_list_for_each'
  - 'bip_for_each_vec'
  - 'bitmap_for_each_clear_region'
  - 'bitmap_for_each_set_region'
  - 'blkg_for_each_descendant_post'
  - 'blkg_for_each_descendant_pre'
  - 'blk_queue_for_each_rl'
  - 'bond_for_each_slave'
  - 'bond_for_each_slave_rcu'
  - 'bpf_for_each_spilled_reg'
  - 'btree_for_each_safe128'
  - 'btree_for_each_safe32'
  - 'btree_for_each_safe64'
  - 'btree_for_each_safel'
  - 'card_for_each_dev'
  - 'cgroup_taskset_for_each'
  - 'cgroup_taskset_for_each_leader'
  - 'cpufreq_for_each_entry'
  - 'cpufreq_for_each_entry_idx'
  - 'cpufreq_for_each_valid_entry'
  - 'cpufreq_for_each_valid_entry_idx'
  - 'css_for_each_child'
  - 'css_for_each_descendant_post'
  - 'css_for_each_descendant_pre'
  - 'device_for_each_child_node'
  - 'displayid_iter_for_each'
  - 'dma_fence_chain_for_each'
  - 'do_for_each_ftrace_op'
  - 'drm_atomic_crtc_for_each_plane'
  - 'drm_atomic_crtc_state_for_each_plane'
  - 'drm_atomic_crtc_state_for_each_plane_state'
  - 'drm_atomic_for_each_plane_damage'
  - 'drm_client_for_each_connector_iter'
  - 'drm_client_for_each_modeset'
  - 'drm_connector_for_each_possible_encoder'
  - 'drm_for_each_bridge_in_chain'
  - 'drm_for_each_connector_iter'
  - 'drm_for_each_crtc'
  - 'drm_for_each_crtc_reverse'
  - 'drm_for_each_encoder'
  - 'drm_for_each_encoder_mask'
  - 'drm_for_each_fb'
  - 'drm_for_each_legacy_plane'
  - 'drm_for_each_plane'
  - 'drm_for_each_plane_mask'
  - 'drm_for_each_privobj'
  - 'drm_mm_for_each_hole'
  - 'drm_mm_for_each_node'
  - 'drm_mm_for_each_node_in_range'
  - 'drm_mm_for_each_node_safe'
  - 'flow_action_for_each'
  - 'for_each_acpi_dev_match'
  - 'for_each_active_dev_scope'
  - 'for_each_active_drhd_unit'
  - 'for_each_active_iommu'
  - 'for_each_aggr_pgid'
  - 'for_each_available_child_of_node'
  - 'for_each_bio'
  - 'for_each_board_func_rsrc'
  - 'for_each_bvec'
  - 'for_each_card_auxs'
  - 'for_each_card_auxs_safe'
  - 'for_each_card_components'
  - 'for_each_card_dapms'
  - 'for_each_card_pre_auxs'
  - 'for_each_card_prelinks'
  - 'for_each_card_rtds'
  - 'for_each_card_rtds_safe'
  - 'for_each_card_widgets'
  - 'for_each_card_widgets_safe'
  - 'for_each_cgroup_storage_type'
  - 'for_each_child_of_node'
  - 'for_each_clear_bit'
  - 'for_each_clear_bit_from'
  - 'for_each_cmsghdr'
  - 'for_each_compatible_node'
  - 'for_each_component_dais'
  - 'for_each_component_dais_safe'
  - 'for_each_comp_order'
  - 'for_each_console'
  - 'for_each_cpu'
  - 'for_each_cpu_and'
  - 'for_each_cpu_not'
  - 'for_each_cpu_wrap'
  - 'for_each_dapm_widgets'
  - 'for_each_dev_addr'
  - 'for_each_dev_scope'
  - 'for_each_dma_cap_mask'
  - 'for_each_dpcm_be'
  - 'for_each_dpcm_be_rollback'
  - 'for_each_dpcm_be_safe'
  - 'for_each_dpcm_fe'
  - 'for_each_drhd_unit'
  - 'for_each_dss_dev'
  - 'for_each_dtpm_table'
  - 'for_each_efi_memory_desc'
  - 'for_each_efi_memory_desc_in_map'
  - 'for_each_element'
  - 'for_each_element_extid'
  - 'for_each_element_id'
  - 'for_each_endpoint_of_node'
  - 'for_each_evictable_lru'
  - 'for_each_fib6_node_rt_rcu'
  - 'for_each_fib6_walker_rt'
  - 'for_each_free_mem_pfn_range_in_zone'
  - 'for_each_free_mem_pfn_range_in_zone_from'
  - 'for_each_free_mem_range'
  - 'for_each_free_mem_range_reverse'
  - 'for_each_func_rsrc'
  - 'for_each_hstate'
  - 'for_each_if'
  - 'for_each_iommu'
  - 'for_each_ip_tunnel_rcu'
  - 'for_each_irq_nr'
  - 'for_each_link_codecs'
  - 'for_each_link_cpus'
  - 'for_each_link_platforms'
  - 'for_each_lru'
  - 'for_each_matching_node'
  - 'for_each_matching_node_and_match'
  - 'for_each_member'
  - 'for_each_memcg_cache_index'
  - 'for_each_mem_pfn_range'
  - '__for_each_mem_range'
  - 'for_each_mem_range'
  - '__for_each_mem_range_rev'
  - 'for_each_mem_range_rev'
  - 'for_each_mem_region'
  - 'for_each_migratetype_order'
  - 'for_each_msi_entry'
  - 'for_each_msi_entry_safe'
  - 'for_each_msi_vector'
  - 'for_each_net'
  - 'for_each_net_continue_reverse'
  - 'for_each_netdev'
  - 'for_each_netdev_continue'
  - 'for_each_netdev_continue_rcu'
  - 'for_each_netdev_continue_reverse'
  - 'for_each_netdev_feature'
  - 'for_each_netdev_in_bond_rcu'
  - 'for_each_netdev_rcu'
  - 'for_each_netdev_reverse'
  - 'for_each_netdev_safe'
  - 'for_each_net_rcu'
  - 'for_each_new_connector_in_state'
  - 'for_each_new_crtc_in_state'
  - 'for_each_new_mst_mgr_in_state'
  - 'for_each_new_plane_in_state'
  - 'for_each_new_private_obj_in_state'
  - 'for_each_node'
  - 'for_each_node_by_name'
  - 'for_each_node_by_type'
  - 'for_each_node_mask'
  - 'for_each_node_state'
  - 'for_each_node_with_cpus'
  - 'for_each_node_with_property'
  - 'for_each_nonreserved_multicast_dest_pgid'
  - 'for_each_of_allnodes'
  - 'for_each_of_allnodes_from'
  - 'for_each_of_cpu_node'
  - 'for_each_of_pci_range'
  - 'for_each_old_connector_in_state'
  - 'for_each_old_crtc_in_state'
  - 'for_each_old_mst_mgr_in_state'
  - 'for_each_oldnew_connector_in_state'
  - 'for_each_oldnew_crtc_in_state'
  - 'for_each_oldnew_mst_mgr_in_state'
  - 'for_each_oldnew_plane_in_state'
  - 'for_each_oldnew_plane_in_state_reverse'
  - 'for_each_oldnew_private_obj_in_state'
  - 'for_each_old_plane_in_state'
  - 'for_each_old_private_obj_in_state'
  - 'for_each_online_cpu'
  - 'for_each_online_node'
  - 'for_each_online_pgdat'
  - 'for_each_pci_bridge'
  - 'for_each_pci_dev'
  - 'for_each_pci_msi_entry'
  - 'for_each_pcm_streams'
  - 'for_each_physmem_range'
  - 'for_each_populated_zone'
  - 'for_each_possible_cpu'
  - 'for_each_present_cpu'
  - 'for_each_prime_number'
  - 'for_each_prime_number_from'
  - 'for_each_process'
  - 'for_each_process_thread'
  - 'for_each_prop_codec_conf'
  - 'for_each_prop_dai_codec'
  - 'for_each_prop_dai_cpu'
  - 'for_each_prop_dlc_codecs'
  - 'for_each_prop_dlc_cpus'
  - 'for_each_prop_dlc_platforms'
  - 'for_each_property_of_node'
  - 'for_each_registered_fb'
  - 'for_each_requested_gpio'
  - 'for_each_requested_gpio_in_range'
  - 'for_each_reserved_mem_range'
  - 'for_each_reserved_mem_region'
  - 'for_each_rtd_codec_dais'
  - 'for_each_rtd_components'
  - 'for_each_rtd_cpu_dais'
  - 'for_each_rtd_dais'
  - 'for_each_set_bit'
  - 'for_each_set_bit_from'
  - 'for_each_set_clump8'
  - 'for_each_sg'
  - 'for_each_sg_dma_page'
  - 'for_each_sg_page'
  - 'for_each_sgtable_dma_page'
  - 'for_each_sgtable_dma_sg'
  - 'for_each_sgtable_page'
  - 'for_each_sgtable_sg'
  - 'for_each_sibling_event'
  - 'for_each_subelement'
  - 'for_each_subelement_extid'
  - 'for_each_subelement_id'
  - '__for_each_thread'
  - 'for_each_thread'
  - 'for_each_unicast_dest_pgid'
  - 'for_each_vsi'
  - 'for_each_wakeup_source'
  - 'for_each_zone'
  - 'for_each_zone_zonelist'
  - 'for_each_zone_zonelist_nodemask'
  - 'fwnode_for_each_available_child_node'
  - 'fwnode_for_each_child_node'
  - 'fwnode_graph_for_each_endpoint'
  - 'gadget_for_each_ep'
  - 'genradix_for_each'
  - 'genradix_for_each_from'
  - 'hash_for_each'
  - 'hash_for_each_possible'
  - 'hash_for_each_possible_rcu'
  - 'hash_for_each_possible_rcu_notrace'
  - 'hash_for_each_possible_safe'
  - 'hash_for_each_rcu'
  - 'hash_for_each_safe'
  - 'hctx_for_each_ctx'
  - 'hlist_bl_for_each_entry'
  - 'hlist_bl_for_each_entry_rcu'
  - 'hlist_bl_for_each_entry_safe'
  - 'hlist_for_each'
  - 'hlist_for_each_entry'
  - 'hlist_for_each_entry_continue'
  - 'hlist_for_each_entry_continue_rcu'
  - 'hlist_for_each_entry_continue_rcu_bh'
  - 'hlist_for_each_entry_from'
  - 'hlist_for_each_entry_from_rcu'
  - 'hlist_for_each_entry_rcu'
  - 'hlist_for_each_entry_rcu_bh'
  - 'hlist_for_each_entry_rcu_notrace'
  - 'hlist_for_each_entry_safe'
  - 'hlist_for_each_entry_srcu'
  - '__hlist_for_each_rcu'
  - 'hlist_for_each_safe'
  - 'hlist_nulls_for_each_entry'
  - 'hlist_nulls_for_each_entry_from'
  - 'hlist_nulls_for_each_entry_rcu'
  - 'hlist_nulls_for_each_entry_safe'
  - 'i3c_bus_for_each_i2cdev'
  - 'i3c_bus_for_each_i3cdev'
  - 'ide_host_for_each_port'
  - 'ide_port_for_each_dev'
  - 'ide_port_for_each_present_dev'
  - 'idr_for_each_entry'
  - 'idr_for_each_entry_continue'
  - 'idr_for_each_entry_continue_ul'
  - 'idr_for_each_entry_ul'
  - 'in_dev_for_each_ifa_rcu'
  - 'in_dev_for_each_ifa_rtnl'
  - 'inet_bind_bucket_for_each'
  - 'inet_lhash2_for_each_icsk_rcu'
  - 'key_for_each'
  - 'key_for_each_safe'
  - 'klp_for_each_func'
  - 'klp_for_each_func_safe'
  - 'klp_for_each_func_static'
  - 'klp_for_each_object'
  - 'klp_for_each_object_safe'
  - 'klp_for_each_object_static'
  - 'kunit_suite_for_each_test_case'
  - 'kvm_for_each_memslot'
  - 'kvm_for_each_vcpu'
  - 'list_for_each'
  - 'list_for_each_codec'
  - 'list_for_each_codec_safe'
  - 'list_for_each_continue'
  - 'list_for_each_entry'
  - 'list_for_each_entry_continue'
  - 'list_for_each_entry_continue_rcu'
  - 'list_for_each_entry_continue_reverse'
  - 'list_for_each_entry_from'
  - 'list_for_each_entry_from_rcu'
  - 'list_for_each_entry_from_reverse'
  - 'list_for_each_entry_lockless'
  - 'list_for_each_entry_rcu'
  - 'list_for_each_entry_reverse'
  - 'list_for_each_entry_safe'
  - 'list_for_each_entry_safe_continue'
  - 'list_for_each_entry_safe_from'
  - 'list_for_each_entry_safe_reverse'
  - 'list_for_each_entry_srcu'
  - 'list_for_each_prev'
  - 'list_for_each_prev_safe'
  - 'list_for_each_safe'
  - 'llist_for_each'
  - 'llist_for_each_entry'
  - 'llist_for_each_entry_safe'
  - 'llist_for_each_safe'
  - 'mci_for_each_dimm'
  - 'media_device_for_each_entity'
  - 'media_device_for_each_intf'
  - 'media_device_for_each_link'
  - 'media_device_for_each_pad'
  - 'nanddev_io_for_each_page'
  - 'netdev_for_each_lower_dev'
  - 'netdev_for_each_lower_private'
  - 'netdev_for_each_lower_private_rcu'
  - 'netdev_for_each_mc_addr'
  - 'netdev_for_each_uc_addr'
  - 'netdev_for_each_upper_dev_rcu'
  - 'netdev_hw_addr_list_for_each'
  - 'nft_rule_for_each_expr'
  - 'nla_for_each_attr'
  - 'nla_for_each_nested'
  - 'nlmsg_for_each_attr'
  - 'nlmsg_for_each_msg'
  - 'nr_neigh_for_each'
  - 'nr_neigh_for_each_safe'
  - 'nr_node_for_each'
  - 'nr_node_for_each_safe'
  - 'of_for_each_phandle'
  - 'of_property_for_each_string'
  - 'of_property_for_each_u32'
  - 'pci_bus_for_each_resource'
  - 'pcl_for_each_chunk'
  - 'pcl_for_each_segment'
  - 'pcm_for_each_format'
  - 'ping_portaddr_for_each_entry'
  - 'plist_for_each'
  - 'plist_for_each_continue'
  - 'plist_for_each_entry'
  - 'plist_for_each_entry_continue'
  - 'plist_for_each_entry_safe'
  - 'plist_for_each_safe'
  - 'pnp_for_each_card'
  - 'pnp_for_each_dev'
  - 'protocol_for_each_card'
  - 'protocol_for_each_dev'
  - 'queue_for_each_hw_ctx'
  - 'radix_tree_for_each_slot'
  - 'radix_tree_for_each_tagged'
  - 'rb_for_each'
  - 'rbtree_postorder_for_each_entry_safe'
  - 'rdma_for_each_block'
  - 'rdma_for_each_port'
  - 'rdma_umem_for_each_dma_block'
  - 'resource_list_for_each_entry'
  - 'resource_list_for_each_entry_safe'
  - 'rhl_for_each_entry_rcu'
  - 'rhl_for_each_rcu'
  - 'rht_for_each'
  - 'rht_for_each_entry'
  - 'rht_for_each_entry_from'
  - 'rht_for_each_entry_rcu'
  - 'rht_for_each_entry_rcu_from'
  - 'rht_for_each_entry_safe'
  - 'rht_for_each_from'
  - 'rht_for_each_rcu'
  - 'rht_for_each_rcu_from'
  - '__rq_for_each_bio'
  - 'rq_for_each_bvec'
  - 'rq_for_each_segment'
  - 'scsi_for_each_prot_sg'
  - 'scsi_for_each_sg'
  - 'sctp_for_each_hentry'
  - 'sctp_skb_for_each'
  - 'shdma_for_each_chan'
  - '__shost_for_each_device'
  - 'shost_for_each_device'
  - 'sk_for_each'
  - 'sk_for_each_bound'
  - 'sk_for_each_entry_offset_rcu'
  - 'sk_for_each_from'
  - 'sk_for_each_rcu'
  - 'sk_for_each_safe'
  - 'sk_nulls_for_each'
  - 'sk_nulls_for_each_from'
  - 'sk_nulls_for_each_rcu'
  - 'snd_array_for_each'
  - 'snd_pcm_group_for_each_entry'
  - 'snd_soc_dapm_widget_for_each_path'
  - 'snd_soc_dapm_widget_for_each_path_safe'
  - 'snd_soc_dapm_widget_for_each_sink_path'
  - 'snd_soc_dapm_widget_for_each_source_path'
  - 'tb_property_for_each'
  - 'tcf_exts_for_each_action'
  - 'udp_portaddr_for_each_entry'
  - 'udp_portaddr_for_each_entry_rcu'
  - 'usb_hub_for_each_child'
  - 'v4l2_device_for_each_subdev'
  - 'v4l2_m2m_for_each_dst_buf'
  - 'v4l2_m2m_for_each_dst_buf_safe'
  - 'v4l2_m2m_for_each_src_buf'
  - 'v4l2_m2m_for_each_src_buf_safe'
  - 'virtio_device_for_each_vq'
  - 'while_for_each_ftrace_op'
  - 'xa_for_each'
  - 'xa_for_each_marked'
  - 'xa_for_each_range'
  - 'xa_for_each_start'
  - 'xas_for_each'
  - 'xas_for_each_conflict'
  - 'xas_for_each_marked'
  - 'xbc_array_for_each_value'
  - 'xbc_for_each_key_value'
  - 'xbc_node_for_each_array_value'
  - 'xbc_node_for_each_child'
  - 'xbc_node_for_each_key_value'
  - 'zorro_for_each_dev'

#IncludeBlocks: Preserve # Unknown to clang-format-5.0
IncludeCategories:
  - Regex: '.*'
    Priority: 1
IncludeIsMainRegex: '(Test)?$'
IndentCaseLabels: false
#IndentPPDirectives: None # Unknown to clang-format-5.0
IndentWidth: 8
IndentWrappedFunctionNames: false
JavaScriptQuotes: Leave
JavaScriptWrapImports: true
KeepEmptyLinesAtTheStartOfBlocks: false
MacroBlockBegin: ''
MacroBlockEnd: ''
MaxEmptyLinesToKeep: 1
NamespaceIndentation: None
#ObjCBinPackProtocolList: Auto # Unknown to clang-format-5.0
ObjCBlockIndentWidth: 8
ObjCSpaceAfterProperty: true
ObjCSpaceBeforeProtocolList: true

# Taken from git's rules
#PenaltyBreakAssignment: 10 # Unknown to clang-format-4.0
PenaltyBreakBeforeFirstCallParameter: 30
PenaltyBreakComment: 10
PenaltyBreakFirstLessLess: 0
PenaltyBreakString: 10
PenaltyExcessCharacter: 100
PenaltyReturnTypeOnItsOwnLine: 60

PointerAlignment: Right
ReflowComments: true
SortIncludes: false
#SortUsingDeclarations: false # Unknown to clang-format-4.0
SpaceAfterCStyleCast: true
SpaceAfterTemplateKeyword: true
SpaceBeforeAssignmentOperators: true
#SpaceBeforeCtorInitializerColon: true # Unknown to clang-format-5.0
#SpaceBeforeInheritanceColon: true # Unknown to clang-format-5.0
SpaceBeforeParens: ControlStatements
#SpaceBeforeRangeBasedForLoopColon: true # Unknown to clang-format-5.0
SpaceInEmptyParentheses: false
SpacesBeforeTrailingComments: 1
SpacesInAngles: false
SpacesInContainerLiterals: false
SpacesInCStyleCastParentheses: false
SpacesInParentheses: false
SpacesInSquareBrackets: false
Standard: Cpp03
TabWidth: 8
UseTab: Always
...

[weirdwiz]

I think the style should also account for very wordy bpf_probe_read(). Or introduce a macro that does the job.

[geyslan]

@weirdwiz do you mean like this?

This macro is already being automatically formatted by the proposed .clang-format to:

[weirdwiz]

Yes, I think the best way is to avoid directly invoking these functions from our own helper function. Makes it very easy to read it.
Because sometimes, to lower the umax_value we need to do some bitwise operation inside the parameters.

[geyslan]

By "avoid directly invoking these functions" do you mean wrapping them (through interfaces)? Could you provide an example?