From 7a87d0597476c4d87b71d46b8b8af756dc736cb3 Mon Sep 17 00:00:00 2001
From: Dan Albert <danalbert@google.com>
Date: Fri, 3 Apr 2015 11:28:46 -0700
Subject: [PATCH] Cleanup base/logging.

Some of this code was unused, most didn't need to be exposed, and we
can just use basename(3).

Also use a better default program name than "unknown".

Change-Id: I62d990f64e4fd0c16aa4b7e907dd06e4f26ddcdd
---
 base/include/base/logging.h | 12 ---------
 base/logging.cpp            | 54 ++++++++++++++++++-------------------
 2 files changed, 26 insertions(+), 40 deletions(-)

diff --git a/base/include/base/logging.h b/base/include/base/logging.h
index 19c1b647b..230adb8b0 100644
--- a/base/include/base/logging.h
+++ b/base/include/base/logging.h
@@ -79,18 +79,6 @@ extern void InitLogging(char* argv[]);
 // Replace the current logger.
 extern void SetLogger(LogFunction&& logger);
 
-// Returns the command line used to invoke the current tool or nullptr if
-// InitLogging hasn't been performed.
-extern const char* GetCmdLine();
-
-// The command used to start the program, such as "/system/bin/dalvikvm". If
-// InitLogging hasn't been performed then just returns "unknown"
-extern const char* ProgramInvocationName();
-
-// A short version of the command used to start the program, such as "dalvikvm".
-// If InitLogging hasn't been performed then just returns "unknown"
-extern const char* ProgramInvocationShortName();
-
 // Logs a message to logcat on Android otherwise to stderr. If the severity is
 // FATAL it also causes an abort. For example:
 //
diff --git a/base/logging.cpp b/base/logging.cpp
index a36ac5f78..0142b7078 100644
--- a/base/logging.cpp
+++ b/base/logging.cpp
@@ -16,6 +16,15 @@
 
 #include "base/logging.h"
 
+#include <libgen.h>
+
+// For getprogname(3) or program_invocation_short_name.
+#if defined(__ANDROID__) || defined(__APPLE__)
+#include <stdlib.h>
+#elif defined(__GLIBC__)
+#include <errno.h>
+#endif
+
 #include <iostream>
 #include <limits>
 #include <mutex>
@@ -47,25 +56,22 @@ static LogFunction gLogger = LogdLogger();
 static LogFunction gLogger = StderrLogger;
 #endif
 
+static bool gInitialized = false;
 static LogSeverity gMinimumLogSeverity = INFO;
-static std::unique_ptr<std::string> gCmdLine;
 static std::unique_ptr<std::string> gProgramInvocationName;
-static std::unique_ptr<std::string> gProgramInvocationShortName;
 
-const char* GetCmdLine() {
-  return (gCmdLine.get() != nullptr) ? gCmdLine->c_str() : nullptr;
+#if defined(__GLIBC__)
+static const char* getprogname() {
+  return program_invocation_short_name;
 }
+#endif
 
-const char* ProgramInvocationName() {
-  return (gProgramInvocationName.get() != nullptr)
-             ? gProgramInvocationName->c_str()
-             : "unknown";
-}
+static const char* ProgramInvocationName() {
+  if (gProgramInvocationName == nullptr) {
+    gProgramInvocationName.reset(new std::string(getprogname()));
+  }
 
-const char* ProgramInvocationShortName() {
-  return (gProgramInvocationShortName.get() != nullptr)
-             ? gProgramInvocationShortName->c_str()
-             : "unknown";
+  return gProgramInvocationName->c_str();
 }
 
 void StderrLogger(LogId, LogSeverity severity, const char*, const char* file,
@@ -73,7 +79,7 @@ void StderrLogger(LogId, LogSeverity severity, const char*, const char* file,
   static const char* log_characters = "VDIWEF";
   CHECK_EQ(strlen(log_characters), FATAL + 1U);
   char severity_char = log_characters[severity];
-  fprintf(stderr, "%s %c %5d %5d %s:%u] %s\n", ProgramInvocationShortName(),
+  fprintf(stderr, "%s %c %5d %5d %s:%u] %s\n", ProgramInvocationName(),
           severity_char, getpid(), gettid(), file, line, message);
 }
 
@@ -121,27 +127,19 @@ void InitLogging(char* argv[], LogFunction&& logger) {
 }
 
 void InitLogging(char* argv[]) {
-  if (gCmdLine.get() != nullptr) {
+  if (gInitialized) {
     return;
   }
 
+  gInitialized = true;
+
   // Stash the command line for later use. We can use /proc/self/cmdline on
   // Linux to recover this, but we don't have that luxury on the Mac, and there
   // are a couple of argv[0] variants that are commonly used.
   if (argv != nullptr) {
-    gCmdLine.reset(new std::string(argv[0]));
-    for (size_t i = 1; argv[i] != nullptr; ++i) {
-      gCmdLine->append(" ");
-      gCmdLine->append(argv[i]);
-    }
-    gProgramInvocationName.reset(new std::string(argv[0]));
-    const char* last_slash = strrchr(argv[0], '/');
-    gProgramInvocationShortName.reset(
-        new std::string((last_slash != nullptr) ? last_slash + 1 : argv[0]));
-  } else {
-    // TODO: fall back to /proc/self/cmdline when argv is NULL on Linux.
-    gCmdLine.reset(new std::string("<unset>"));
+    gProgramInvocationName.reset(new std::string(basename(argv[0])));
   }
+
   const char* tags = getenv("ANDROID_LOG_TAGS");
   if (tags == nullptr) {
     return;
@@ -288,7 +286,7 @@ std::ostream& LogMessage::stream() {
 
 void LogMessage::LogLine(const char* file, unsigned int line, LogId id,
                          LogSeverity severity, const char* message) {
-  const char* tag = ProgramInvocationShortName();
+  const char* tag = ProgramInvocationName();
   std::lock_guard<std::mutex> lock(logging_lock);
   gLogger(id, severity, tag, file, line, message);
 }