让adb logcat打印内核调试信息

在默认情况下，adb logcat只能显示使用程序的调试信息，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: Unexp ected 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，全部运用了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，有须要的朋友可以继续完备。