Add posix I/O writer

CMakeLists.txt

@@ -102,6 +102,7 @@ find_package(StdFilesystem REQUIRED)
 find_package(Sensors)
 find_package(Veosinfo)
 find_package(PkgConfig)
+find_package(BpfObject)
 
 if(PkgConfig_FOUND)
     pkg_check_modules(Audit audit)
@@ -122,6 +123,9 @@ CMAKE_DEPENDENT_OPTION(USE_LIBAUDIT "Use libaudit for syscall name resolution" O
 add_feature_info("USE_LIBAUDIT" USE_LIBAUDIT "Use libaudit for syscall name resolution.")
 CMAKE_DEPENDENT_OPTION(USE_VEOSINFO "Use libveosinfo to sample NEC SX-Aurora Tsubasa cards." ON "Veosinfo_FOUND" OFF)
 add_feature_info("USE_VEOSINFO" USE_VEOSINFO "Use libveosinfo to sample NEC SX-Aurora  Tsubasa cards.")
+CMAKE_DEPENDENT_OPTION(USE_BPF "Use BPF for filename lookup" ON BpfObject_FOUND OFF)
+add_feature_info("USE_BPF" USE_BPF "Use BPF for filename lookup")
+
 # system configuration checks
 CHECK_INCLUDE_FILES(linux/hw_breakpoint.h HAVE_HW_BREAKPOINT_H)
 CHECK_STRUCT_HAS_MEMBER("struct perf_event_attr" clockid linux/perf_event.h HAVE_PERF_EVENT_ATTR_CLOCKID)
@@ -349,6 +353,18 @@ target_include_directories(lo2s PRIVATE
     ${CMAKE_CURRENT_BINARY_DIR}/include
 )
 
+
+if (USE_BPF)
+    if (BpfObject_FOUND)
+        target_compile_definitions(lo2s PUBLIC HAVE_BPF)
+        bpf_object(open src/perf/posix_io/open.bpf.c)
+        add_dependencies(lo2s open_skel)
+        target_link_libraries(lo2s PRIVATE open_skel)
+    else()
+        message(SEND_ERROR "BPF not found but requested.")
+    endif()
+endif()
+
 add_subdirectory(man)
 
 message(STATUS "Linux kernel version: ${LINUX_VERSION}")

cmake/FindBpfObject.cmake

@@ -0,0 +1,189 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+#[=======================================================================[.rst:
+FindBpfObject
+--------
+
+Find BpfObject
+
+This module finds if all the dependencies for eBPF Compile-Once-Run-Everywhere
+programs are available and where all the components are located.
+
+The caller may set the following variables to disable automatic
+search/processing for the associated component:
+
+  ``BPFOBJECT_BPFTOOL_EXE``
+    Path to ``bpftool`` binary
+
+  ``BPFOBJECT_CLANG_EXE``
+    Path to ``clang`` binary
+
+  ``LIBBPF_INCLUDE_DIRS``
+    Path to ``libbpf`` development headers
+
+  ``LIBBPF_LIBRARIES``
+    Path to `libbpf` library
+
+  ``BPFOBJECT_VMLINUX_H``
+    Path to ``vmlinux.h`` generated by ``bpftool``. If unset, this module will
+    attempt to automatically generate a copy.
+
+This module sets the following result variables:
+
+::
+
+  BpfObject_FOUND             = TRUE if all components are found
+
+
+This module also provides the ``bpf_object()`` macro. This macro generates a
+cmake interface library for the BPF object's generated skeleton as well
+as the associated dependencies.
+
+.. code-block:: cmake
+
+  bpf_object(<name> <source>)
+
+Given an abstract ``<name>`` for a BPF object and the associated ``<source>``
+file, generates an interface library target, ``<name>_skel``, that may be
+linked against by other cmake targets.
+
+Example Usage:
+
+::
+
+  find_package(BpfObject REQUIRED)
+  bpf_object(myobject myobject.bpf.c)
+  add_executable(myapp myapp.c)
+  target_link_libraries(myapp myobject_skel)
+
+#]=======================================================================]
+
+if(NOT BPFOBJECT_BPFTOOL_EXE)
+  find_program(BPFOBJECT_BPFTOOL_EXE NAMES bpftool DOC "Path to bpftool executable")
+endif()
+
+if(NOT BPFOBJECT_CLANG_EXE)
+  find_program(BPFOBJECT_CLANG_EXE NAMES clang DOC "Path to clang executable")
+
+  execute_process(COMMAND ${BPFOBJECT_CLANG_EXE} --version
+    OUTPUT_VARIABLE CLANG_version_output
+    ERROR_VARIABLE CLANG_version_error
+    RESULT_VARIABLE CLANG_version_result
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+  # Check that clang is new enough
+  if(${CLANG_version_result} EQUAL 0)
+    if("${CLANG_version_output}" MATCHES "clang version ([^\n]+)\n")
+      # Transform X.Y.Z into X;Y;Z which can then be interpreted as a list
+      set(CLANG_VERSION "${CMAKE_MATCH_1}")
+      string(REPLACE "." ";" CLANG_VERSION_LIST ${CLANG_VERSION})
+      list(GET CLANG_VERSION_LIST 0 CLANG_VERSION_MAJOR)
+
+      # Anything older than clang 10 doesn't really work
+      string(COMPARE LESS ${CLANG_VERSION_MAJOR} 10 CLANG_VERSION_MAJOR_LT10)
+      if(${CLANG_VERSION_MAJOR_LT10})
+        message(FATAL_ERROR "clang ${CLANG_VERSION} is too old for BPF CO-RE")
+      endif()
+
+      message(STATUS "Found clang version: ${CLANG_VERSION}")
+    else()
+      message(FATAL_ERROR "Failed to parse clang version string: ${CLANG_version_output}")
+    endif()
+  else()
+    message(FATAL_ERROR "Command \"${BPFOBJECT_CLANG_EXE} --version\" failed with output:\n${CLANG_version_error}")
+  endif()
+endif()
+
+if(NOT LIBBPF_INCLUDE_DIRS OR NOT LIBBPF_LIBRARIES)
+  find_package(LibBpf)
+endif()
+
+if(BPFOBJECT_VMLINUX_H)
+  get_filename_component(GENERATED_VMLINUX_DIR ${BPFOBJECT_VMLINUX_H} DIRECTORY)
+elseif(BPFOBJECT_BPFTOOL_EXE)
+  # Generate vmlinux.h
+  set(GENERATED_VMLINUX_DIR ${CMAKE_CURRENT_BINARY_DIR}/include/lo2s)
+  set(BPFOBJECT_VMLINUX_H "${GENERATED_VMLINUX_DIR}/vmlinux.h")
+
+file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/include/lo2s")
+  execute_process(COMMAND ${BPFOBJECT_BPFTOOL_EXE} btf dump file /sys/kernel/btf/vmlinux format c
+    OUTPUT_FILE ${BPFOBJECT_VMLINUX_H}
+    ERROR_VARIABLE VMLINUX_error
+    RESULT_VARIABLE VMLINUX_result)
+  if(${VMLINUX_result} EQUAL 0)
+    set(VMLINUX ${BPFOBJECT_VMLINUX_H})
+  else()
+    message(FATAL_ERROR "Failed to dump vmlinux.h from BTF: ${VMLINUX_error}")
+  endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(BpfObject
+  REQUIRED_VARS
+    BPFOBJECT_BPFTOOL_EXE
+    BPFOBJECT_CLANG_EXE
+    LIBBPF_INCLUDE_DIRS
+    LIBBPF_LIBRARIES
+    GENERATED_VMLINUX_DIR)
+
+# Get clang bpf system includes
+execute_process(
+  COMMAND bash -c "${BPFOBJECT_CLANG_EXE} -v -E - < /dev/null 2>&1 |
+          sed -n '/<...> search starts here:/,/End of search list./{ s| \\(/.*\\)|-idirafter \\1|p }'"
+  OUTPUT_VARIABLE CLANG_SYSTEM_INCLUDES_output
+  ERROR_VARIABLE CLANG_SYSTEM_INCLUDES_error
+  RESULT_VARIABLE CLANG_SYSTEM_INCLUDES_result
+  OUTPUT_STRIP_TRAILING_WHITESPACE)
+if(${CLANG_SYSTEM_INCLUDES_result} EQUAL 0)
+  separate_arguments(CLANG_SYSTEM_INCLUDES UNIX_COMMAND ${CLANG_SYSTEM_INCLUDES_output})
+  message(STATUS "BPF system include flags: ${CLANG_SYSTEM_INCLUDES}")
+else()
+  message(FATAL_ERROR "Failed to determine BPF system includes: ${CLANG_SYSTEM_INCLUDES_error}")
+endif()
+
+# Get target arch
+execute_process(COMMAND uname -m
+  COMMAND sed -e "s/x86_64/x86/" -e "s/aarch64/arm64/" -e "s/ppc64le/powerpc/" -e "s/mips.*/mips/"
+  OUTPUT_VARIABLE ARCH_output
+  ERROR_VARIABLE ARCH_error
+  RESULT_VARIABLE ARCH_result
+  OUTPUT_STRIP_TRAILING_WHITESPACE)
+if(${ARCH_result} EQUAL 0)
+  set(ARCH ${ARCH_output})
+  message(STATUS "BPF target arch: ${ARCH}")
+else()
+  message(FATAL_ERROR "Failed to determine target architecture: ${ARCH_error}")
+endif()
+
+# Public macro
+macro(bpf_object name input)
+  set(BPF_C_FILE ${CMAKE_CURRENT_SOURCE_DIR}/${input})
+  set(BPF_O_FILE ${CMAKE_CURRENT_BINARY_DIR}/${name}.bpf.o)
+  set(BPF_SKEL_FILE ${CMAKE_CURRENT_BINARY_DIR}/include/lo2s/${name}.skel.h)
+  message(STATUS ${CMAKE_CURRENT_BINARY_DIR})
+  set(OUTPUT_TARGET ${name}_skel)
+
+  # Build BPF object file
+  add_custom_command(OUTPUT ${BPF_O_FILE}
+    COMMAND ${BPFOBJECT_CLANG_EXE} -g -O2 -target bpf -D__TARGET_ARCH_${ARCH}
+    ${CLANG_SYSTEM_INCLUDES} -I${GENERATED_VMLINUX_DIR}
+    -I${CMAKE_SOURCE_DIR}/include
+            -isystem ${LIBBPF_INCLUDE_DIRS} -c ${BPF_C_FILE} -o ${BPF_O_FILE}
+    COMMAND_EXPAND_LISTS
+    VERBATIM
+    DEPENDS ${BPF_C_FILE}
+    COMMENT "[clang] Building BPF object: ${name}")
+
+  # Build BPF skeleton header
+  add_custom_command(OUTPUT ${BPF_SKEL_FILE}
+    COMMAND bash -c "${BPFOBJECT_BPFTOOL_EXE} gen skeleton ${BPF_O_FILE} > ${BPF_SKEL_FILE}"
+    VERBATIM
+    DEPENDS ${BPF_O_FILE}
+    COMMENT "[skel]  Building BPF skeleton: ${name}")
+
+  add_library(${OUTPUT_TARGET} INTERFACE)
+  target_sources(${OUTPUT_TARGET} INTERFACE ${BPF_SKEL_FILE})
+  target_include_directories(${OUTPUT_TARGET} INTERFACE ${CMAKE_CURRENT_BINARY_DIR})
+  target_include_directories(${OUTPUT_TARGET} SYSTEM INTERFACE ${LIBBPF_INCLUDE_DIRS})
+  target_link_libraries(${OUTPUT_TARGET} INTERFACE ${LIBBPF_LIBRARIES} -lelf -lz)
+endmacro()

cmake/FindLibBpf.cmake

@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+find_path(LIBBPF_INCLUDE_DIRS
+  NAMES
+    bpf/bpf.h
+    bpf/btf.h
+    bpf/libbpf.h
+  PATHS
+    /usr/include
+    /usr/local/include
+    /opt/local/include
+    /sw/include
+    ENV CPATH)
+
+find_library(LIBBPF_LIBRARIES
+  NAMES
+    bpf
+  PATHS
+    /usr/lib
+    /usr/local/lib
+    /opt/local/lib
+    /sw/lib
+    ENV LIBRARY_PATH
+    ENV LD_LIBRARY_PATH)
+
+include (FindPackageHandleStandardArgs)
+
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(LibBpf "Please install the libbpf development package"
+  LIBBPF_LIBRARIES
+  LIBBPF_INCLUDE_DIRS)
+
+mark_as_advanced(LIBBPF_INCLUDE_DIRS LIBBPF_LIBRARIES)

include/lo2s/config.hpp

@@ -91,6 +91,8 @@ struct Config
     bool use_x86_energy;
     // block I/O
     bool use_block_io;
+    // posix I/O
+    bool use_posix_io;
     // syscalls
     bool use_syscalls = false;
     std::vector<int64_t> syscall_filter;

include/lo2s/measurement_scope.hpp

@@ -32,6 +32,7 @@ enum class MeasurementScopeType
     USERSPACE_METRIC,
     BIO,
     SYSCALL,
+    POSIX_IO,
     UNKNOWN
 };
 
@@ -73,6 +74,11 @@ struct MeasurementScope
         return { MeasurementScopeType::SYSCALL, s };
     }
 
+    static MeasurementScope posix_io(ExecutionScope s)
+    {
+        return { MeasurementScopeType::POSIX_IO, s };
+    }
+
     friend bool operator==(const MeasurementScope& lhs, const MeasurementScope& rhs)
     {
         return (lhs.scope == rhs.scope) && lhs.type == rhs.type;
@@ -103,6 +109,8 @@ struct MeasurementScope
             return fmt::format("block layer I/O events for {}", scope.name());
         case MeasurementScopeType::SYSCALL:
             return fmt::format("syscall events for {}", scope.name());
+        case MeasurementScopeType::POSIX_IO:
+            return fmt::format("POSIX I/O events for {}", scope.name());
         default:
             throw new std::runtime_error("Unknown ExecutionScopeType!");
         }

include/lo2s/monitor/poll_monitor.hpp

@@ -55,7 +55,7 @@ class PollMonitor : public ThreadedMonitor
 
     void add_fd(int fd);
 
-    virtual void monitor([[maybe_unused]] int fd){};
+    virtual void monitor([[maybe_unused]] int fd) {};
 
     struct pollfd& stop_pfd()
     {