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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This source set defines shared expectations for:
// 1. The packed-data format used to pass information from chrome.dll
// to chrome_elf.dll across restarts.
// 2. The APIs exported by chrome_elf.dll to share logs of module load attempts.
#ifndef CHROME_ELF_THIRD_PARTY_DLLS_LOGGING_API_H_
#define CHROME_ELF_THIRD_PARTY_DLLS_LOGGING_API_H_
#include <windows.h>
#include <stdint.h>
namespace third_party_dlls {
//------------------------------------------------------------------------------
// chrome_elf log API
//------------------------------------------------------------------------------
// Load-attempt log types.
enum LogType : uint8_t {
kBlocked,
kAllowed,
};
// Define a flat log entry for any attempted module load.
// The total size in bytes of a log entry is returned by GetLogEntrySize().
// - Note: If this is a |blocked| entry, |path_len| will be 0.
// (Full path not required for a blacklisted load attempt log.)
struct LogEntry {
LogType type;
uint8_t basename_hash[20];
uint8_t code_id_hash[20];
// Number of characters in |path| string, not including null terminator.
uint32_t path_len;
// UTF-8 full module path, null termination guaranteed.
char path[1];
};
static_assert(sizeof(LogEntry) == 52,
"Ensure expectations for padding and alignment are correct. "
"If this changes, double check GetLogEntrySize() calculation.");
// Returns the full size for a LogEntry, given the LogEntry.path_len.
// - Always use this function over manual calculation, as it handles padding
// and alignment.
// - This function will be built into the caller binary.
// - Example of how to use this function to iterate through a buffer returned
// from DrainLog():
//
// uint8_t* tracker = buffer;
// while (tracker < buffer + buffer_bytes_written) {
// LogEntry* entry = reinterpret_cast<LogEntry*>(tracker);
// // Do work.
// tracker += GetLogEntrySize(entry->path_len);
// }
uint32_t GetLogEntrySize(uint32_t path_len);
} // namespace third_party_dlls
// Exported API for calling from outside chrome_elf.dll.
// Drains the load attempt LogEntries into the provided buffer.
// - Returns the number of bytes written. See comments above for LogEntry
// details.
// - If provided, |log_remaining| receives the number of bytes remaining in the
// module log, that didn't fit in |buffer|.
// - |buffer_size| can be 0, in which case this simply queries the size of the
// module log.
extern "C" uint32_t DrainLog(uint8_t* buffer,
uint32_t buffer_size,
uint32_t* log_remaining);
// Exported API for calling from outside chrome_elf.dll.
// Register an event to be notified when load-attempt logs are available
// via DrainLog API.
// - Pass in a HANDLE to an event created via ::CreateEvent(), or nullptr to
// clear.
// - This function will duplicate |event_handle|, and call ::SetEvent() when any
// new load-attempt log is added.
extern "C" bool RegisterLogNotification(HANDLE event_handle);
#endif // CHROME_ELF_THIRD_PARTY_DLLS_LOGGING_API_H_