Export functions necessary for ebpf-go port (microsoft#4116)

* Export ebpf_close_fd and ebpf_dup_fd Export functions used to manipulate fd_t. This makes the use of the UCRT _get_osfhandle an implementation detail which is abstracted away from users of ebpfapi.dll. This also makes it easier to use the API via run-time dynamic linking. * Allow attaching a link as an fd Add a function which returns the link as an fd when attaching a program. The existing functions are re-jigged to reduce code duplication. * Export functions to translate between GUID and enums Allow users to resolve libbpf style enums to Windows GUIDs and vice versa. * Fix up spelling mistakes Co-authored-by: Dave Thaler <dthaler1968@gmail.com> * Fix sorting of Source.def * Rename to ebpf_program_attach_fds * Add tests for ebpf_dup_fd and ebpf_close_fd * Rename link argument to link_handle * Document return value of ebpf_program_attach_fds Co-authored-by: Dave Thaler <dthaler1968@gmail.com> * Fix ebpf_get_attach_type use-after-free * Rename ebpf_dup_fd to ebpf_duplicate_fd * Rename to ebpf_program_attach_by_fds * Fix docstring of ebpf_get_ebpf_attach_type * Temporarily disable _wer_report::_terminate_hook --------- Co-authored-by: Dave Thaler <dthaler1968@gmail.com>
Alan-Jowett · Feb 13, 2025 · d8b9204 · d8b9204
1 parent c0bfd35
commit d8b9204
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Showing 14 changed files with 345 additions and 116 deletions.
diff --git a/ebpfapi/Source.def b/ebpfapi/Source.def
@@ -109,12 +109,18 @@ EXPORTS
     ebpf_api_close_handle
     ebpf_api_get_pinned_map_info
     ebpf_api_map_info_free
+    ebpf_close_fd
+    ebpf_duplicate_fd
     ebpf_enumerate_programs
     ebpf_enumerate_sections = ebpf_enumerate_programs
     ebpf_free_programs
     ebpf_free_sections = ebpf_free_programs
     ebpf_free_string
     ebpf_get_attach_type_name
+    ebpf_get_bpf_attach_type
+    ebpf_get_bpf_program_type
+    ebpf_get_ebpf_attach_type
+    ebpf_get_ebpf_program_type
     ebpf_get_next_pinned_object_path
     ebpf_get_next_pinned_program_path
     ebpf_get_program_info_from_verifier
@@ -127,6 +133,7 @@ EXPORTS
     ebpf_object_unpin
     ebpf_program_attach
     ebpf_program_attach_by_fd
+    ebpf_program_attach_by_fds
     ebpf_program_query_info
     ebpf_ring_buffer_map_write
     ebpf_store_delete_program_information
@@ -142,5 +149,5 @@ EXPORTS
     libbpf_num_possible_cpus
     libbpf_prog_type_by_name
     libbpf_strerror
+    ring_buffer__free
     ring_buffer__new
-    ring_buffer__free
diff --git a/include/ebpf_api.h b/include/ebpf_api.h
@@ -418,6 +418,22 @@ extern "C"
         size_t attach_parameters_size,
         _Outptr_ struct bpf_link** link) EBPF_NO_EXCEPT;
 
+    /**
+     * @brief Attach an eBPF program by program file descriptor and return
+     * the link as a file descriptor.
+     *
+     * @see ebpf_program_attach_by_fd
+     *
+     * @retval EBPF_SUCCESS The operation was successful.
+     */
+    _Must_inspect_result_ ebpf_result_t
+    ebpf_program_attach_by_fds(
+        fd_t program_fd,
+        _In_opt_ const ebpf_attach_type_t* attach_type,
+        _In_reads_bytes_opt_(attach_parameters_size) void* attach_parameters,
+        size_t attach_parameters_size,
+        _Out_ fd_t* link) EBPF_NO_EXCEPT;
+
     /**
      * @brief Detach an eBPF program from an attach point represented by
      *  the bpf_link structure.
@@ -473,6 +489,17 @@ extern "C"
     _Must_inspect_result_ ebpf_result_t
     ebpf_close_fd(fd_t fd) EBPF_NO_EXCEPT;
 
+    /**
+     * @brief Duplicate a file descriptor.
+     *
+     * @param [in] fd File descriptor to be duplicated.
+     * @param [out] dup Duplicated file descriptor.
+     *
+     * @retval EBPF_SUCCESS The operation was successful.
+     */
+    _Must_inspect_result_ ebpf_result_t
+    ebpf_duplicate_fd(fd_t fd, _Out_ fd_t* dup) EBPF_NO_EXCEPT;
+
     /**
      * @brief Get eBPF program type and expected attach type by name.
      *
@@ -599,6 +626,49 @@ extern "C"
     ebpf_ring_buffer_map_write(
         fd_t ring_buffer_map_fd, _In_reads_bytes_(data_length) const void* data, size_t data_length) EBPF_NO_EXCEPT;
 
+    /**
+     * @brief Get eBPF program type for the specified BPF program type.
+     *
+     * @param[in] program_type BPF program type.
+     *
+     * @returns Pointer to eBPF program type, or NULL if not found.
+     */
+    _Ret_maybenull_ const ebpf_program_type_t*
+    ebpf_get_ebpf_program_type(bpf_prog_type_t bpf_program_type) EBPF_NO_EXCEPT;
+
+    /**
+     * @brief Get eBPF attach type for the specified BPF attach type.
+     *
+     * @param[in] bpf_attach_type BPF attach type.
+     * @param[out] ebpf_attach_type eBPF attach type or GUID_NULL.
+     *
+     * @retval EBPF_SUCCESS The operation was successful.
+     * @retval EBPF_INVALID_ARGUMENT The attach type is unknown.
+     */
+    _Must_inspect_result_ ebpf_result_t
+    ebpf_get_ebpf_attach_type(bpf_attach_type_t bpf_attach_type, _Out_ ebpf_attach_type_t* ebpf_attach_type)
+        EBPF_NO_EXCEPT;
+
+    /**
+     * @brief Get BPF program type for the specified eBPF program type.
+     *
+     * @param[in] program_type eBPF program type GUID.
+     *
+     * @returns BPF program type, or BPF_PROG_TYPE_UNSPEC if not found.
+     */
+    bpf_prog_type_t
+    ebpf_get_bpf_program_type(_In_ const ebpf_program_type_t* program_type) EBPF_NO_EXCEPT;
+
+    /**
+     * @brief Get BPF attach type for the specified eBPF attach type.
+     *
+     * @param[in] attach_type eBPF attach type GUID.
+     *
+     * @returns BPF attach type, or BPF_ATTACH_TYPE_UNSPEC if not found.
+     */
+    bpf_attach_type_t
+    ebpf_get_bpf_attach_type(_In_ const ebpf_attach_type_t* ebpf_attach_type) EBPF_NO_EXCEPT;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libs/api/api_internal.h b/libs/api/api_internal.h
@@ -712,16 +712,6 @@ ebpf_program_load_bytes(
     _Out_ fd_t* program_fd) noexcept;
 #endif
 
-/**
- * @brief Get eBPF program type for the specified bpf program type.
- *
- * @param[in] program_type Bpf program type.
- *
- * @returns Pointer to eBPF program type, or NULL if not found.
- */
-_Ret_maybenull_ const ebpf_program_type_t*
-ebpf_get_ebpf_program_type(bpf_prog_type_t bpf_program_type) noexcept;
-
 /**
  * @brief Get eBPF attach type for the specified bpf attach type.
  *
@@ -732,26 +722,6 @@ ebpf_get_ebpf_program_type(bpf_prog_type_t bpf_program_type) noexcept;
 _Ret_maybenull_ const ebpf_attach_type_t*
 get_ebpf_attach_type(bpf_attach_type_t bpf_attach_type) noexcept;
 
-/**
- * @brief Get bpf program type for the specified eBPF program type.
- *
- * @param[in] program_type eBPF program type GUID.
- *
- * @returns Bpf program type, or BPF_PROG_TYPE_UNSPEC if not found.
- */
-bpf_prog_type_t
-get_bpf_program_type(_In_ const ebpf_program_type_t* program_type) noexcept;
-
-/**
- * @brief Get bpf attach type for the specified eBPF attach type.
- *
- * @param[in] attach_type eBPF attach type GUID.
- *
- * @returns Bpf attach type, or BPF_ATTACH_TYPE_UNSPEC if not found.
- */
-bpf_attach_type_t
-get_bpf_attach_type(_In_ const ebpf_attach_type_t* ebpf_attach_type) noexcept;
-
 /**
  * @brief Initialize the eBPF library's thread local storage.
  */