让adb logcat打印内核调试信息

让adb logcat打印内核调试信息
Wednesday, October 14th, 2009 | Author: admin | ? Edit ?


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文章出处：http://www.limodev.cn/blog
作者联系方式：李先静 <xianjimli at hotmail dot com>

在默认情况下，adb logcat只能显示应用程序的调试信息，我把logcat.cpp修改了一下，让它同时可以打印内核调试信息：

system/core/logcat/logcat.cpp

static void readLogLines(int logfd)
{
char buffer[256] = {0};
while (1) {
unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1] __attribute__((aligned(4)));
struct logger_entry *entry = (struct logger_entry *) buf;
int ret;

ret = read(logfd, entry, LOGGER_ENTRY_MAX_LEN);
if (ret < 0) {
if (errno == EINTR)
continue;
if (errno == EAGAIN)
break;
perror("logcat read");
exit(EXIT_FAILURE);
}
else if (!ret) {
fprintf(stderr, "read: Unexpected EOF!/n");
exit(EXIT_FAILURE);
}

/* NOTE: driver guarantees we read exactly one full entry */

entry->msg[entry->len] = '/0';

if (g_printBinary) {
printBinary(entry);
} else {
(void) processBuffer(entry);
}

/*读入内核调试信息*/
if((ret = klogctl(9, buffer, sizeof(buffer))) > 0) {
if((ret = klogctl(2, buffer, sizeof(buffer))) > 0) {
entry->tid = 0;
entry->pid = getpid();
/*priority*/
entry->msg[0] = ANDROID_LOG_INFO;
/*tag*/
strcpy(entry->msg+1, KERNEL_TAG);
/*message*/
strncpy(entry->msg+1+sizeof(KERNEL_TAG), buffer, ret);
entry->len = 1 + sizeof(KERNEL_TAG) + ret + 1;
entry->msg[entry->len] = '/0';
if (g_printBinary) {
printBinary(entry);
} else {
(void) processBuffer(entry);
}
}
}
}
}

这里没有把内核调试信息的级别转换成Androind的LOG级别，全部使用了ANDROID_LOG_INFO级别，进程ID用了当前的进程ID。对我们来说已经够用了，有需要的朋友可以继续完善。