Merge "Add StdioLogger for command-line tools."

base/include/android-base/logging.h

@@ -100,8 +100,17 @@ using LogFunction = std::function<void(LogId, LogSeverity, const char*, const ch
                                        unsigned int, const char*)>;
 using AbortFunction = std::function<void(const char*)>;
 
+// Loggers for use with InitLogging/SetLogger.
+
+// Log to the kernel log (dmesg).
 void KernelLogger(LogId, LogSeverity, const char*, const char*, unsigned int, const char*);
+// Log to stderr in the full logcat format (with pid/tid/time/tag details).
 void StderrLogger(LogId, LogSeverity, const char*, const char*, unsigned int, const char*);
+// Log just the message to stdout/stderr (without pid/tid/time/tag details).
+// The choice of stdout versus stderr is based on the severity.
+// Errors are also prefixed by the program name (as with err(3)/error(3)).
+// Useful for replacing printf(3)/perror(3)/err(3)/error(3) in command-line tools.
+void StdioLogger(LogId, LogSeverity, const char*, const char*, unsigned int, const char*);
 
 void DefaultAborter(const char* abort_message);
 

base/include/android-base/test_utils.h

@@ -58,21 +58,33 @@ class TemporaryDir {
   DISALLOW_COPY_AND_ASSIGN(TemporaryDir);
 };
 
-class CapturedStderr {
+class CapturedStdFd {
  public:
-  CapturedStderr();
-  ~CapturedStderr();
+  CapturedStdFd(int std_fd);
+  ~CapturedStdFd();
 
   int fd() const;
+  std::string str();
 
  private:
-  void init();
-  void reset();
+  void Init();
+  void Reset();
 
   TemporaryFile temp_file_;
-  int old_stderr_;
+  int std_fd_;
+  int old_fd_;
 
-  DISALLOW_COPY_AND_ASSIGN(CapturedStderr);
+  DISALLOW_COPY_AND_ASSIGN(CapturedStdFd);
+};
+
+class CapturedStderr : public CapturedStdFd {
+ public:
+  CapturedStderr() : CapturedStdFd(STDERR_FILENO) {}
+};
+
+class CapturedStdout : public CapturedStdFd {
+ public:
+  CapturedStdout() : CapturedStdFd(STDOUT_FILENO) {}
 };
 
 #define ASSERT_MATCH(str, pattern)                                             \

base/logging.cpp

@@ -212,6 +212,16 @@ void StderrLogger(LogId, LogSeverity severity, const char* tag, const char* file
           timestamp, getpid(), GetThreadId(), file, line, message);
 }
 
+void StdioLogger(LogId, LogSeverity severity, const char* /*tag*/, const char* /*file*/,
+                 unsigned int /*line*/, const char* message) {
+  if (severity >= WARNING) {
+    fflush(stdout);
+    fprintf(stderr, "%s: %s\n", getprogname(), message);
+  } else {
+    fprintf(stdout, "%s\n", message);
+  }
+}
+
 void DefaultAborter(const char* abort_message) {
 #ifdef __ANDROID__
   android_set_abort_message(abort_message);

base/logging_test.cpp

@@ -206,11 +206,9 @@ static std::string make_log_pattern(android::base::LogSeverity severity,
 }
 #endif
 
-static void CheckMessage(const CapturedStderr& cap, android::base::LogSeverity severity,
+static void CheckMessage(CapturedStderr& cap, android::base::LogSeverity severity,
                          const char* expected, const char* expected_tag = nullptr) {
-  std::string output;
-  ASSERT_EQ(0, lseek(cap.fd(), 0, SEEK_SET));
-  android::base::ReadFdToString(cap.fd(), &output);
+  std::string output = cap.str();
 
   // We can't usefully check the output of any of these on Windows because we
   // don't have std::regex, but we can at least make sure we printed at least as
@@ -623,3 +621,23 @@ TEST(logging, SetDefaultTag) {
   }
   CheckMessage(cap, android::base::LogSeverity::INFO, expected_msg, expected_tag);
 }
+
+TEST(logging, StdioLogger) {
+  std::string err_str;
+  std::string out_str;
+  {
+    CapturedStderr cap_err;
+    CapturedStdout cap_out;
+    android::base::SetLogger(android::base::StdioLogger);
+    LOG(INFO) << "out";
+    LOG(ERROR) << "err";
+    err_str = cap_err.str();
+    out_str = cap_out.str();
+  }
+
+  // For INFO we expect just the literal "out\n".
+  ASSERT_EQ("out\n", out_str) << out_str;
+  // Whereas ERROR logging includes the program name.
+  ASSERT_EQ(android::base::Basename(android::base::GetExecutablePath()) + ": err\n", err_str)
+      << err_str;
+}

base/test_utils.cpp

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-#include "android-base/logging.h"
 #include "android-base/test_utils.h"
 
 #include <fcntl.h>
@@ -33,6 +32,9 @@
 
 #include <string>
 
+#include <android-base/file.h>
+#include <android-base/logging.h>
+
 #ifdef _WIN32
 int mkstemp(char* template_name) {
   if (_mktemp(template_name) == nullptr) {
@@ -123,31 +125,38 @@ bool TemporaryDir::init(const std::string& tmp_dir) {
   return (mkdtemp(path) != nullptr);
 }
 
-CapturedStderr::CapturedStderr() : old_stderr_(-1) {
-  init();
+CapturedStdFd::CapturedStdFd(int std_fd) : std_fd_(std_fd), old_fd_(-1) {
+  Init();
 }
 
-CapturedStderr::~CapturedStderr() {
-  reset();
+CapturedStdFd::~CapturedStdFd() {
+  Reset();
 }
 
-int CapturedStderr::fd() const {
+int CapturedStdFd::fd() const {
   return temp_file_.fd;
 }
 
-void CapturedStderr::init() {
+std::string CapturedStdFd::str() {
+  std::string result;
+  CHECK_EQ(0, TEMP_FAILURE_RETRY(lseek(fd(), 0, SEEK_SET)));
+  android::base::ReadFdToString(fd(), &result);
+  return result;
+}
+
+void CapturedStdFd::Init() {
 #if defined(_WIN32)
   // On Windows, stderr is often buffered, so make sure it is unbuffered so
   // that we can immediately read back what was written to stderr.
-  CHECK_EQ(0, setvbuf(stderr, NULL, _IONBF, 0));
+  if (std_fd_ == STDERR_FILENO) CHECK_EQ(0, setvbuf(stderr, NULL, _IONBF, 0));
 #endif
-  old_stderr_ = dup(STDERR_FILENO);
-  CHECK_NE(-1, old_stderr_);
-  CHECK_NE(-1, dup2(fd(), STDERR_FILENO));
+  old_fd_ = dup(std_fd_);
+  CHECK_NE(-1, old_fd_);
+  CHECK_NE(-1, dup2(fd(), std_fd_));
 }
 
-void CapturedStderr::reset() {
-  CHECK_NE(-1, dup2(old_stderr_, STDERR_FILENO));
-  CHECK_EQ(0, close(old_stderr_));
+void CapturedStdFd::Reset() {
+  CHECK_NE(-1, dup2(old_fd_, std_fd_));
+  CHECK_EQ(0, close(old_fd_));
   // Note: cannot restore prior setvbuf() setting.
 }

init/host_init_parser.cpp

@@ -48,7 +48,7 @@ static Result<Success> do_stub(const BuiltinArguments& args) {
 #include "generated_stub_builtin_function_map.h"
 
 int main(int argc, char** argv) {
-    android::base::InitLogging(argv, &android::base::StderrLogger);
+    android::base::InitLogging(argv, &android::base::StdioLogger);
     if (argc != 2) {
         LOG(ERROR) << "Usage: " << argv[0] << " <init file to parse>";
         return -1;