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Telegram/ThirdParty/dispatch/os/firehose_buffer_private.h

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+/*
+ * Copyright (c) 2015 Apple Inc. All rights reserved.
+ *
+ * @APPLE_APACHE_LICENSE_HEADER_START@
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @APPLE_APACHE_LICENSE_HEADER_END@
+ */
+
+#ifndef __FIREHOSE_BUFFER_PRIVATE__
+#define __FIREHOSE_BUFFER_PRIVATE__
+
+#if OS_FIREHOSE_SPI
+#ifdef KERNEL
+#include <stdint.h>
+#else
+#include <os/base.h>
+#include <os/availability.h>
+#include <os/base_private.h>
+#include <dispatch/dispatch.h>
+#endif
+
+#define OS_FIREHOSE_SPI_VERSION 20180226
+
+/*!
+ * @group Firehose SPI
+ * SPI intended for logd only
+ * Layout of structs is subject to change without notice
+ */
+
+#define FIREHOSE_BUFFER_LIBTRACE_HEADER_SIZE	2048ul
+#define FIREHOSE_BUFFER_KERNEL_MIN_CHUNK_COUNT	16
+#define FIREHOSE_BUFFER_KERNEL_MAX_CHUNK_COUNT	64
+
+typedef struct firehose_buffer_range_s {
+	uint16_t fbr_offset; // offset from the start of the buffer
+	uint16_t fbr_length;
+} *firehose_buffer_range_t;
+
+#ifdef KERNEL
+
+typedef struct firehose_chunk_s *firehose_chunk_t;
+
+// implemented by the kernel
+extern void __firehose_buffer_push_to_logd(firehose_buffer_t fb, bool for_io);
+extern void __firehose_critical_region_enter(void);
+extern void __firehose_critical_region_leave(void);
+extern void __firehose_allocate(vm_offset_t *addr, vm_size_t size);
+extern uint8_t __firehose_buffer_kernel_chunk_count;
+extern uint8_t __firehose_num_kernel_io_pages;
+
+#define FIREHOSE_BUFFER_KERNEL_DEFAULT_CHUNK_COUNT FIREHOSE_BUFFER_KERNEL_MIN_CHUNK_COUNT
+#define FIREHOSE_BUFFER_KERNEL_DEFAULT_IO_PAGES    8
+
+#define FIREHOSE_BUFFER_KERNEL_CHUNK_COUNT __firehose_buffer_kernel_chunk_count
+#define FIREHOSE_BUFFER_CHUNK_PREALLOCATED_COUNT (__firehose_buffer_kernel_chunk_count - 1) // the first chunk is the header
+
+// exported for the kernel
+firehose_tracepoint_t
+__firehose_buffer_tracepoint_reserve(uint64_t stamp, firehose_stream_t stream,
+		uint16_t pubsize, uint16_t privsize, uint8_t **privptr);
+
+void
+__firehose_buffer_tracepoint_flush(firehose_tracepoint_t vat,
+		firehose_tracepoint_id_u vatid);
+
+firehose_buffer_t
+__firehose_buffer_create(size_t *size);
+
+void
+__firehose_merge_updates(firehose_push_reply_t update);
+
+int
+__firehose_kernel_configuration_valid(uint8_t chunk_count, uint8_t io_pages);
+
+#else
+
+#define __firehose_critical_region_enter()
+#define __firehose_critical_region_leave()
+
+OS_EXPORT
+const uint32_t _firehose_spi_version;
+
+OS_ALWAYS_INLINE
+static inline const uint8_t *
+_firehose_tracepoint_reader_init(firehose_chunk_t fc, const uint8_t **endptr)
+{
+	const uint8_t *start = fc->fc_data;
+	const uint8_t *end = fc->fc_start + fc->fc_pos.fcp_next_entry_offs;
+
+	if (end > fc->fc_start + FIREHOSE_CHUNK_SIZE) {
+		end = start;
+	}
+	*endptr = end;
+	return start;
+}
+
+OS_ALWAYS_INLINE
+static inline firehose_tracepoint_t
+_firehose_tracepoint_reader_next(const uint8_t **ptr, const uint8_t *end)
+{
+	const uint16_t ft_size = offsetof(struct firehose_tracepoint_s, ft_data);
+	struct ft_unaligned_s {
+		struct firehose_tracepoint_s ft;
+	} __attribute__((packed, aligned(1))) *uft;
+
+	do {
+		uft = (struct ft_unaligned_s *)*ptr;
+		if (uft->ft.ft_data >= end) {
+			// reached the end
+			return NULL;
+		}
+		if (!uft->ft.ft_length) {
+			// tracepoint write didn't even start
+			return NULL;
+		}
+		if (uft->ft.ft_length > end - uft->ft.ft_data) {
+			// invalid length
+			return NULL;
+		}
+		*ptr += roundup(ft_size + uft->ft.ft_length, 8);
+		// test whether write of the tracepoint was finished
+	} while (os_unlikely(uft->ft.ft_id.ftid_value == 0));
+
+	return (firehose_tracepoint_t)uft;
+}
+
+#define firehose_tracepoint_foreach(ft, fbc) \
+		for (const uint8_t *end, *p = _firehose_tracepoint_reader_init(fbc, &end); \
+				((ft) = _firehose_tracepoint_reader_next(&p, end)); )
+
+OS_ALWAYS_INLINE
+static inline bool
+firehose_buffer_range_validate(firehose_chunk_t fc, firehose_tracepoint_t ft,
+		firehose_buffer_range_t range)
+{
+	if (range->fbr_offset + range->fbr_length > FIREHOSE_CHUNK_SIZE) {
+		return false;
+	}
+	if (fc->fc_start + range->fbr_offset < ft->ft_data + ft->ft_length) {
+		return false;
+	}
+	return true;
+}
+
+#endif // !KERNEL
+
+#endif // OS_FIREHOSE_SPI
+
+#endif // __FIREHOSE_BUFFER_PRIVATE__