cleanup code, check errno usage

encfs/RawFileIO.cpp

@@ -90,6 +90,8 @@ Interface RawFileIO::interface() const { return RawFileIO_iface; }
     This works around the problem described in
    https://github.com/vgough/encfs/issues/181
     Without this, "umask 0777 ; echo foo > bar" fails.
+
+    Sets errno when -1 is returned.
 */
 static int open_readonly_workaround(const char *path, int flags) {
   int fd = -1;
@@ -118,13 +120,12 @@ int RawFileIO::open(int flags) {
   bool requestWrite = (((flags & O_RDWR) != 0) || ((flags & O_WRONLY) != 0));
   VLOG(1) << "open call, requestWrite = " << requestWrite;
 
-  int result = 0;
-
   // if we have a descriptor and it is writable, or we don't need writable..
   if ((fd >= 0) && (canWrite || !requestWrite)) {
     VLOG(1) << "using existing file descriptor";
-    result = fd;  // success
-  } else {
+    return fd;  // success
+  }
+
   int finalFlags = requestWrite ? O_RDWR : O_RDONLY;
 
 #if defined(O_LARGEFILE)
@@ -135,8 +136,11 @@ int RawFileIO::open(int flags) {
 #warning O_LARGEFILE not supported
 #endif
 
+  int eno;
   int newFd = ::open(name.c_str(), finalFlags);
-    int eno = errno;
+  if (newFd < 0) {
+    eno = errno;
+  }
 
   VLOG(1) << "open file with flags " << finalFlags << ", result = " << newFd;
 
@@ -146,7 +150,11 @@ int RawFileIO::open(int flags) {
     eno = errno;
   }
 
-    if (newFd >= 0) {
+  if (newFd < 0) {
+    RLOG(DEBUG) << "::open error: " << strerror(eno);
+    return -eno;
+  }
+
   if (oldfd >= 0) {
     RLOG(ERROR) << "leaking FD?: oldfd = " << oldfd << ", fd = " << fd
                 << ", newfd = " << newFd;
@@ -156,14 +164,9 @@ int RawFileIO::open(int flags) {
   // now.
   canWrite = requestWrite;
   oldfd = fd;
-      result = fd = newFd;
-    } else {
-      result = -eno;
-      RLOG(DEBUG) << "::open error: " << strerror(eno);
-    }
-  }
+  fd = newFd;
 
-  return result;
+  return fd;
 }
 
 int RawFileIO::getAttr(struct stat *stbuf) const {
@@ -206,8 +209,6 @@ ssize_t RawFileIO::read(const IORequest &req) const {
 
   if (readSize < 0) {
     int eno = errno;
-    errno = 0;  // just to be sure error seen in integration tests really comes
-                // from the function rc.
     RLOG(WARNING) << "read failed at offset " << req.offset << " for "
                   << req.dataLen << " bytes: " << strerror(eno);
     return -eno;

encfs/main.cpp

@@ -532,10 +532,9 @@ void *encfs_init(fuse_conn_info *conn) {
     int res =
         pthread_create(&ctx->monitorThread, nullptr, idleMonitor, (void *)ctx);
     if (res != 0) {
-      int eno = errno;
       RLOG(ERROR) << "error starting idle monitor thread, "
                      "res = "
-                  << res << ", " << strerror(eno);
+                  << res << ", " << strerror(res);
     }
   }