commit f93b4006e0b1afdf304b39d13f96d9766ec14a30
author Tom Cherry <tomcherry@google.com> Wed Jun 03 09:23:49 2020 -0700
committer Tom Cherry <tomcherry@google.com> Wed Jun 03 16:29:48 2020 -0700
tree 9f5a7eba41c964b28ccb3f549451b0c5cd36e76f
parent 671f39fdf2f4938306aa78c9d12ab28088f73947

logd: use libbase logging

We can use libbase logging to output to the kernel log instead of the
'prdebug' function, so use that instead.

Bonus #1: we can now use CHECK().
Bonus #2: logging unit tests automatically output to stderr.
Bonus #3: We see dependent library's logs instead of losing them to
the void.

Test: logging unit tests
Test: logs show appropriately in dmesg / stderr
Test: CHECK() works
Change-Id: I92f8056b4820dc4998996cf46460568085299700

logd/main.cpp

diff --git a/logd/main.cpp b/logd/main.cpp
index c2b5a1d..773ffb8 100644
--- a/logd/main.cpp
+++ b/logd/main.cpp
@@ -36,7 +36,9 @@
 
 #include <memory>
 
+#include <android-base/logging.h>
 #include <android-base/macros.h>
+#include <android-base/stringprintf.h>
 #include <cutils/android_get_control_file.h>
 #include <cutils/sockets.h>
 #include <log/event_tag_map.h>
@@ -70,19 +72,18 @@
     sched_param param = {};
 
     if (set_sched_policy(0, SP_BACKGROUND) < 0) {
-        android::prdebug("failed to set background scheduling policy");
+        PLOG(ERROR) << "failed to set background scheduling policy";
         return -1;
     }
 
     if (sched_setscheduler((pid_t)0, SCHED_BATCH, &param) < 0) {
-        android::prdebug("failed to set batch scheduler");
+        PLOG(ERROR) << "failed to set batch scheduler";
         return -1;
     }
 
-    if (!__android_logger_property_get_bool("ro.debuggable",
-                                            BOOL_DEFAULT_FALSE) &&
+    if (!__android_logger_property_get_bool("ro.debuggable", BOOL_DEFAULT_FALSE) &&
         prctl(PR_SET_DUMPABLE, 0) == -1) {
-        android::prdebug("failed to clear PR_SET_DUMPABLE");
+        PLOG(ERROR) << "failed to clear PR_SET_DUMPABLE";
         return -1;
     }
 
@@ -105,40 +106,13 @@
         return -1;
     }
     if (cap_set_proc(caps.get()) < 0) {
-        android::prdebug("failed to set CAP_SYSLOG or CAP_AUDIT_CONTROL (%d)", errno);
+        PLOG(ERROR) << "failed to set CAP_SYSLOG or CAP_AUDIT_CONTROL";
         return -1;
     }
 
     return 0;
 }
 
-static int fdDmesg = -1;
-void android::prdebug(const char* fmt, ...) {
-    if (fdDmesg < 0) {
-        return;
-    }
-
-    static const char message[] = {
-        KMSG_PRIORITY(LOG_DEBUG), 'l', 'o', 'g', 'd', ':', ' '
-    };
-    char buffer[256];
-    memcpy(buffer, message, sizeof(message));
-
-    va_list ap;
-    va_start(ap, fmt);
-    int n = vsnprintf(buffer + sizeof(message),
-                      sizeof(buffer) - sizeof(message), fmt, ap);
-    va_end(ap);
-    if (n > 0) {
-        buffer[sizeof(buffer) - 1] = '\0';
-        if (!strchr(buffer, '\n')) {
-            buffer[sizeof(buffer) - 2] = '\0';
-            strlcat(buffer, "\n", sizeof(buffer));
-        }
-        write(fdDmesg, buffer, strlen(buffer));
-    }
-}
-
 char* android::uidToName(uid_t u) {
     struct Userdata {
         uid_t uid;
@@ -246,8 +220,20 @@
         return issueReinit();
     }
 
+    android::base::InitLogging(
+            argv, [](android::base::LogId log_id, android::base::LogSeverity severity,
+                     const char* tag, const char* file, unsigned int line, const char* message) {
+                if (tag && strcmp(tag, "logd") != 0) {
+                    auto prefixed_message = android::base::StringPrintf("%s: %s", tag, message);
+                    android::base::KernelLogger(log_id, severity, "logd", file, line,
+                                                prefixed_message.c_str());
+                } else {
+                    android::base::KernelLogger(log_id, severity, "logd", file, line, message);
+                }
+            });
+
     static const char dev_kmsg[] = "/dev/kmsg";
-    fdDmesg = android_get_control_file(dev_kmsg);
+    int fdDmesg = android_get_control_file(dev_kmsg);
     if (fdDmesg < 0) {
         fdDmesg = TEMP_FAILURE_RETRY(open(dev_kmsg, O_WRONLY | O_CLOEXEC));
     }
@@ -263,7 +249,7 @@
             fdPmesg = TEMP_FAILURE_RETRY(
                 open(proc_kmsg, O_RDONLY | O_NDELAY | O_CLOEXEC));
         }
-        if (fdPmesg < 0) android::prdebug("Failed to open %s\n", proc_kmsg);
+        if (fdPmesg < 0) PLOG(ERROR) << "Failed to open " << proc_kmsg;
     }
 
     bool auditd = __android_logger_property_get_bool("ro.logd.auditd", BOOL_DEFAULT_TRUE);