From 43a123c1ae6613b3efeed291fa552ecd909d3acf Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:23:18 +0200 Subject: Adding upstream version 1.20.14. Signed-off-by: Daniel Baumann --- src/runtime/write_err_android.go | 162 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 162 insertions(+) create mode 100644 src/runtime/write_err_android.go (limited to 'src/runtime/write_err_android.go') diff --git a/src/runtime/write_err_android.go b/src/runtime/write_err_android.go new file mode 100644 index 0000000..a876900 --- /dev/null +++ b/src/runtime/write_err_android.go @@ -0,0 +1,162 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package runtime + +import "unsafe" + +var ( + writeHeader = []byte{6 /* ANDROID_LOG_ERROR */, 'G', 'o', 0} + writePath = []byte("/dev/log/main\x00") + writeLogd = []byte("/dev/socket/logdw\x00") + + // guarded by printlock/printunlock. + writeFD uintptr + writeBuf [1024]byte + writePos int +) + +// Prior to Android-L, logging was done through writes to /dev/log files implemented +// in kernel ring buffers. In Android-L, those /dev/log files are no longer +// accessible and logging is done through a centralized user-mode logger, logd. +// +// https://android.googlesource.com/platform/system/core/+/refs/tags/android-6.0.1_r78/liblog/logd_write.c +type loggerType int32 + +const ( + unknown loggerType = iota + legacy + logd + // TODO(hakim): logging for emulator? +) + +var logger loggerType + +func writeErr(b []byte) { + if logger == unknown { + // Use logd if /dev/socket/logdw is available. + if v := uintptr(access(&writeLogd[0], 0x02 /* W_OK */)); v == 0 { + logger = logd + initLogd() + } else { + logger = legacy + initLegacy() + } + } + + // Write to stderr for command-line programs. + write(2, unsafe.Pointer(&b[0]), int32(len(b))) + + // Log format: "
\x00\x00" + // + //
+ // In legacy mode: "". + // In logd mode: "" + // + // The entire log needs to be delivered in a single syscall (the NDK + // does this with writev). Each log is its own line, so we need to + // buffer writes until we see a newline. + var hlen int + switch logger { + case logd: + hlen = writeLogdHeader() + case legacy: + hlen = len(writeHeader) + } + + dst := writeBuf[hlen:] + for _, v := range b { + if v == 0 { // android logging won't print a zero byte + v = '0' + } + dst[writePos] = v + writePos++ + if v == '\n' || writePos == len(dst)-1 { + dst[writePos] = 0 + write(writeFD, unsafe.Pointer(&writeBuf[0]), int32(hlen+writePos)) + for i := range dst { + dst[i] = 0 + } + writePos = 0 + } + } +} + +func initLegacy() { + // In legacy mode, logs are written to /dev/log/main + writeFD = uintptr(open(&writePath[0], 0x1 /* O_WRONLY */, 0)) + if writeFD == 0 { + // It is hard to do anything here. Write to stderr just + // in case user has root on device and has run + // adb shell setprop log.redirect-stdio true + msg := []byte("runtime: cannot open /dev/log/main\x00") + write(2, unsafe.Pointer(&msg[0]), int32(len(msg))) + exit(2) + } + + // Prepopulate the invariant header part. + copy(writeBuf[:len(writeHeader)], writeHeader) +} + +// used in initLogdWrite but defined here to avoid heap allocation. +var logdAddr sockaddr_un + +func initLogd() { + // In logd mode, logs are sent to the logd via a unix domain socket. + logdAddr.family = _AF_UNIX + copy(logdAddr.path[:], writeLogd) + + // We are not using non-blocking I/O because writes taking this path + // are most likely triggered by panic, we cannot think of the advantage of + // non-blocking I/O for panic but see disadvantage (dropping panic message), + // and blocking I/O simplifies the code a lot. + fd := socket(_AF_UNIX, _SOCK_DGRAM|_O_CLOEXEC, 0) + if fd < 0 { + msg := []byte("runtime: cannot create a socket for logging\x00") + write(2, unsafe.Pointer(&msg[0]), int32(len(msg))) + exit(2) + } + + errno := connect(fd, unsafe.Pointer(&logdAddr), int32(unsafe.Sizeof(logdAddr))) + if errno < 0 { + msg := []byte("runtime: cannot connect to /dev/socket/logdw\x00") + write(2, unsafe.Pointer(&msg[0]), int32(len(msg))) + // TODO(hakim): or should we just close fd and hope for better luck next time? + exit(2) + } + writeFD = uintptr(fd) + + // Prepopulate invariant part of the header. + // The first 11 bytes will be populated later in writeLogdHeader. + copy(writeBuf[11:11+len(writeHeader)], writeHeader) +} + +// writeLogdHeader populates the header and returns the length of the payload. +func writeLogdHeader() int { + hdr := writeBuf[:11] + + // The first 11 bytes of the header corresponds to android_log_header_t + // as defined in system/core/include/private/android_logger.h + // hdr[0] log type id (unsigned char), defined in + // hdr[1:2] tid (uint16_t) + // hdr[3:11] log_time defined in + // hdr[3:7] sec unsigned uint32, little endian. + // hdr[7:11] nsec unsigned uint32, little endian. + hdr[0] = 0 // LOG_ID_MAIN + sec, nsec, _ := time_now() + packUint32(hdr[3:7], uint32(sec)) + packUint32(hdr[7:11], uint32(nsec)) + + // TODO(hakim): hdr[1:2] = gettid? + + return 11 + len(writeHeader) +} + +func packUint32(b []byte, v uint32) { + // little-endian. + b[0] = byte(v) + b[1] = byte(v >> 8) + b[2] = byte(v >> 16) + b[3] = byte(v >> 24) +} -- cgit v1.2.3