[XRay] Encapsulate all FD log related logic into a class

This abstracts away the file descriptor related logic which makes it
easier to port XRay to platform that don't use file descriptors or
file system for writing the log data, such as Fuchsia.

Differential Revision: https://reviews.llvm.org/D52161

llvm-svn: 344578

1 files changed, 20 insertions, 46 deletions

diff --git a/compiler-rt/lib/xray/xray_utils.cc b/compiler-rt/lib/xray/xray_utils.cc
index 5753354a412..22c0dfa70a6 100644
--- a/compiler-rt/lib/xray/xray_utils.cc
+++ b/compiler-rt/lib/xray/xray_utils.cc
@@ -12,7 +12,9 @@
 //===----------------------------------------------------------------------===//
 #include "xray_utils.h"
 
+#include "sanitizer_common/sanitizer_allocator_internal.h"
 #include "sanitizer_common/sanitizer_common.h"
+#include "xray_allocator.h"
 #include "xray_defs.h"
 #include "xray_flags.h"
 #include <cstdio>
@@ -31,7 +33,11 @@ void printToStdErr(const char *Buffer) XRAY_NEVER_INSTRUMENT {
   fprintf(stderr, "%s", Buffer);
 }
 
-void retryingWriteAll(int Fd, const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
+LogWriter::~LogWriter() {
+  internal_close(Fd);
+}
+
+void LogWriter::WriteAll(const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
   if (Begin == End)
     return;
   auto TotalBytes = std::distance(Begin, End);
@@ -49,50 +55,11 @@ void retryingWriteAll(int Fd, const char *Begin, const char *End) XRAY_NEVER_INS
   }
 }
 
-std::pair<ssize_t, bool> retryingReadSome(int Fd, char *Begin,
-                                          char *End) XRAY_NEVER_INSTRUMENT {
-  auto BytesToRead = std::distance(Begin, End);
-  ssize_t BytesRead;
-  ssize_t TotalBytesRead = 0;
-  while (BytesToRead && (BytesRead = read(Fd, Begin, BytesToRead))) {
-    if (BytesRead == -1) {
-      if (errno == EINTR)
-        continue;
-      Report("Read error; errno = %d\n", errno);
-      return std::make_pair(TotalBytesRead, false);
-    }
-
-    TotalBytesRead += BytesRead;
-    BytesToRead -= BytesRead;
-    Begin += BytesRead;
-  }
-  return std::make_pair(TotalBytesRead, true);
+void LogWriter::Flush() XRAY_NEVER_INSTRUMENT {
+  fsync(Fd);
 }
 
-bool readValueFromFile(const char *Filename,
-                       long long *Value) XRAY_NEVER_INSTRUMENT {
-  int Fd = open(Filename, O_RDONLY | O_CLOEXEC);
-  if (Fd == -1)
-    return false;
-  static constexpr size_t BufSize = 256;
-  char Line[BufSize] = {};
-  ssize_t BytesRead;
-  bool Success;
-  std::tie(BytesRead, Success) = retryingReadSome(Fd, Line, Line + BufSize);
-  if (!Success)
-    return false;
-  close(Fd);
-  const char *End = nullptr;
-  long long Tmp = internal_simple_strtoll(Line, &End, 10);
-  bool Result = false;
-  if (Line[0] != '\0' && (*End == '\n' || *End == '\0')) {
-    *Value = Tmp;
-    Result = true;
-  }
-  return Result;
-}
-
-int getLogFD() XRAY_NEVER_INSTRUMENT {
+LogWriter *LogWriter::Open() XRAY_NEVER_INSTRUMENT {
   // Open a temporary file once for the log.
   char TmpFilename[256] = {};
   char TmpWildcardPattern[] = "XXXXXX";
@@ -108,18 +75,25 @@ int getLogFD() XRAY_NEVER_INSTRUMENT {
       flags()->xray_logfile_base, Progname, TmpWildcardPattern);
   if (NeededLength > int(sizeof(TmpFilename))) {
     Report("XRay log file name too long (%d): %s\n", NeededLength, TmpFilename);
-    return -1;
+    return nullptr;
   }
   int Fd = mkstemp(TmpFilename);
   if (Fd == -1) {
     Report("XRay: Failed opening temporary file '%s'; not logging events.\n",
            TmpFilename);
-    return -1;
+    return nullptr;
   }
   if (Verbosity())
     Report("XRay: Log file in '%s'\n", TmpFilename);
 
-  return Fd;
+  LogWriter *LW = allocate<LogWriter>();
+  new (LW) LogWriter(Fd);
+  return LW;
+}
+
+void LogWriter::Close(LogWriter *LW) {
+  LW->~LogWriter();
+  deallocate(LW);
 }
 
 } // namespace __xray