libc/async_safe/include/async_safe/log.h

/*
 * Copyright (C) 2010 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#pragma once

#include <sys/cdefs.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>

// This file is an alternative to <android/log.h>, but reuses
// `android_LogPriority` and should not have conflicting identifiers.
#include <android/log.h>

// These functions do not allocate memory to send data to the log.

__BEGIN_DECLS

// Formats a message to the log (priority 'fatal'), then aborts.
// Implemented as a macro so that async_safe_fatal isn't on the stack when we crash:
// we appear to go straight from the caller to abort, saving an uninteresting stack
// frame.
#define async_safe_fatal(...) \
  do { \
    async_safe_fatal_no_abort(__VA_ARGS__); \
    abort(); \
  } while (0) \


// These functions do return, so callers that want to abort, must do so themselves,
// or use the macro above.
void async_safe_fatal_no_abort(const char* fmt, ...) __printflike(1, 2);
void async_safe_fatal_va_list(const char* prefix, const char* fmt, va_list args);

//
// Formatting routines for the C library's internal debugging.
// Unlike the usual alternatives, these don't allocate, and they don't drag in all of stdio.
// These are async signal safe, so they can be called from signal handlers.
//

int async_safe_format_buffer(char* buf, size_t size, const char* fmt, ...) __printflike(3, 4);
int async_safe_format_buffer_va_list(char* buffer, size_t buffer_size, const char* format, va_list args);

int async_safe_format_fd(int fd, const char* format , ...) __printflike(2, 3);
int async_safe_format_fd_va_list(int fd, const char* format, va_list args);
int async_safe_format_log(int priority, const char* tag, const char* fmt, ...) __printflike(3, 4);
int async_safe_format_log_va_list(int priority, const char* tag, const char* fmt, va_list ap);
int async_safe_write_log(int priority, const char* tag, const char* msg);

__END_DECLS