crash_dump: during early boot, output to kmsg on userdebug.
am: 3e76ecaf80
Change-Id: I72baab899157ebc2e0379e0bd2a46d61c6f5ed8f
diff --git a/debuggerd/libdebuggerd/utility.cpp b/debuggerd/libdebuggerd/utility.cpp
index 22fde5e..7f450e6 100644
--- a/debuggerd/libdebuggerd/utility.cpp
+++ b/debuggerd/libdebuggerd/utility.cpp
@@ -22,16 +22,22 @@
#include <signal.h>
#include <string.h>
#include <sys/ptrace.h>
+#include <sys/uio.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <backtrace/Backtrace.h>
#include <log/log.h>
+using android::base::unique_fd;
+
// Whitelist output desired in the logcat output.
bool is_allowed_in_logcat(enum logtype ltype) {
if ((ltype == HEADER)
@@ -42,6 +48,19 @@
return false;
}
+static bool should_write_to_kmsg() {
+ // Write to kmsg if tombstoned isn't up, and we're able to do so.
+ if (!android::base::GetBoolProperty("ro.debuggable", false)) {
+ return false;
+ }
+
+ if (android::base::GetProperty("init.svc.tombstoned", "") == "running") {
+ return false;
+ }
+
+ return true;
+}
+
__attribute__((__weak__, visibility("default")))
void _LOG(log_t* log, enum logtype ltype, const char* fmt, ...) {
bool write_to_tombstone = (log->tfd != -1);
@@ -49,6 +68,7 @@
&& log->crashed_tid != -1
&& log->current_tid != -1
&& (log->crashed_tid == log->current_tid);
+ static bool write_to_kmsg = should_write_to_kmsg();
char buf[512];
va_list ap;
@@ -70,6 +90,30 @@
if (log->amfd_data != nullptr) {
*log->amfd_data += buf;
}
+
+ if (write_to_kmsg) {
+ unique_fd kmsg_fd(open("/dev/kmsg_debug", O_WRONLY | O_APPEND | O_CLOEXEC));
+ if (kmsg_fd.get() >= 0) {
+ // Our output might contain newlines which would otherwise be handled by the android logger.
+ // Split the lines up ourselves before sending to the kernel logger.
+ if (buf[len - 1] == '\n') {
+ buf[len - 1] = '\0';
+ }
+
+ std::vector<std::string> fragments = android::base::Split(buf, "\n");
+ for (const std::string& fragment : fragments) {
+ static constexpr char prefix[] = "<3>DEBUG: ";
+ struct iovec iov[3];
+ iov[0].iov_base = const_cast<char*>(prefix);
+ iov[0].iov_len = strlen(prefix);
+ iov[1].iov_base = const_cast<char*>(fragment.c_str());
+ iov[1].iov_len = fragment.length();
+ iov[2].iov_base = const_cast<char*>("\n");
+ iov[2].iov_len = 1;
+ TEMP_FAILURE_RETRY(writev(kmsg_fd.get(), iov, 3));
+ }
+ }
+ }
}
}
@@ -205,7 +249,7 @@
}
void read_with_default(const char* path, char* buf, size_t len, const char* default_value) {
- android::base::unique_fd fd(open(path, O_RDONLY));
+ unique_fd fd(open(path, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
int rc = TEMP_FAILURE_RETRY(read(fd.get(), buf, len - 1));
if (rc != -1) {
diff --git a/init/Android.mk b/init/Android.mk
index 2bf453d..3886ed5 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -9,12 +9,14 @@
-DALLOW_LOCAL_PROP_OVERRIDE=1 \
-DALLOW_PERMISSIVE_SELINUX=1 \
-DREBOOT_BOOTLOADER_ON_PANIC=1 \
+ -DWORLD_WRITABLE_KMSG=1 \
-DDUMP_ON_UMOUNT_FAILURE=1
else
init_options += \
-DALLOW_LOCAL_PROP_OVERRIDE=0 \
-DALLOW_PERMISSIVE_SELINUX=0 \
-DREBOOT_BOOTLOADER_ON_PANIC=0 \
+ -DWORLD_WRITABLE_KMSG=0 \
-DDUMP_ON_UMOUNT_FAILURE=0
endif
diff --git a/init/init.cpp b/init/init.cpp
index 4cd2e2b..f340bc2 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -933,6 +933,9 @@
LOG(INFO) << "Running restorecon...";
selinux_android_restorecon("/dev", 0);
selinux_android_restorecon("/dev/kmsg", 0);
+ if constexpr (WORLD_WRITABLE_KMSG) {
+ selinux_android_restorecon("/dev/kmsg_debug", 0);
+ }
selinux_android_restorecon("/dev/socket", 0);
selinux_android_restorecon("/dev/random", 0);
selinux_android_restorecon("/dev/urandom", 0);
@@ -1036,7 +1039,13 @@
setgroups(arraysize(groups), groups);
mount("sysfs", "/sys", "sysfs", 0, NULL);
mount("selinuxfs", "/sys/fs/selinux", "selinuxfs", 0, NULL);
+
mknod("/dev/kmsg", S_IFCHR | 0600, makedev(1, 11));
+
+ if constexpr (WORLD_WRITABLE_KMSG) {
+ mknod("/dev/kmsg_debug", S_IFCHR | 0622, makedev(1, 11));
+ }
+
mknod("/dev/random", S_IFCHR | 0666, makedev(1, 8));
mknod("/dev/urandom", S_IFCHR | 0666, makedev(1, 9));