Fix cases of overwriting errno

Summary:AsyncSocket has a few cases where
we might overwrite errno, with another function
call that is done during use.

For example withAddr could cause an EBADF if the fd
was bad.

This fixes these cases by copying errno, before doing
anything else

Reviewed By: afrind

Differential Revision: D3101932

fb-gh-sync-id: 73d4810314c90cb987936a0a3a9dc977af07243a
fbshipit-source-id: 73d4810314c90cb987936a0a3a9dc977af07243a

folly/io/async/AsyncSocket.cpp

@@ -298,9 +298,11 @@ void AsyncSocket::setShutdownSocketSet(ShutdownSocketSet* newSS) {
 void AsyncSocket::setCloseOnExec() {
   int rv = fcntl(fd_, F_SETFD, FD_CLOEXEC);
   if (rv != 0) {
-    throw AsyncSocketException(AsyncSocketException::INTERNAL_ERROR,
-                               withAddr("failed to set close-on-exec flag"),
-                               errno);
+    auto errnoCopy = errno;
+    throw AsyncSocketException(
+        AsyncSocketException::INTERNAL_ERROR,
+        withAddr("failed to set close-on-exec flag"),
+        errnoCopy);
   }
 }
 
@@ -338,8 +340,11 @@ void AsyncSocket::connect(ConnectCallback* callback,
     // implementations the PF_foo and AF_foo constants are identical.
     fd_ = socket(address.getFamily(), SOCK_STREAM, 0);
     if (fd_ < 0) {
-      throw AsyncSocketException(AsyncSocketException::INTERNAL_ERROR,
-                                withAddr("failed to create socket"), errno);
+      auto errnoCopy = errno;
+      throw AsyncSocketException(
+          AsyncSocketException::INTERNAL_ERROR,
+          withAddr("failed to create socket"),
+          errnoCopy);
     }
     if (shutdownSocketSet_) {
       shutdownSocketSet_->add(fd_);
@@ -351,25 +356,30 @@ void AsyncSocket::connect(ConnectCallback* callback,
     // Put the socket in non-blocking mode
     int flags = fcntl(fd_, F_GETFL, 0);
     if (flags == -1) {
-      throw AsyncSocketException(AsyncSocketException::INTERNAL_ERROR,
-                                withAddr("failed to get socket flags"), errno);
+      auto errnoCopy = errno;
+      throw AsyncSocketException(
+          AsyncSocketException::INTERNAL_ERROR,
+          withAddr("failed to get socket flags"),
+          errnoCopy);
     }
     int rv = fcntl(fd_, F_SETFL, flags | O_NONBLOCK);
     if (rv == -1) {
+      auto errnoCopy = errno;
       throw AsyncSocketException(
           AsyncSocketException::INTERNAL_ERROR,
           withAddr("failed to put socket in non-blocking mode"),
-          errno);
+          errnoCopy);
     }
 
 #if !defined(MSG_NOSIGNAL) && defined(F_SETNOSIGPIPE)
     // iOS and OS X don't support MSG_NOSIGNAL; set F_SETNOSIGPIPE instead
     rv = fcntl(fd_, F_SETNOSIGPIPE, 1);
     if (rv == -1) {
+      auto errnoCopy = errno;
       throw AsyncSocketException(
           AsyncSocketException::INTERNAL_ERROR,
           "failed to enable F_SETNOSIGPIPE on socket",
-          errno);
+          errnoCopy);
     }
 #endif
 
@@ -387,21 +397,23 @@ void AsyncSocket::connect(ConnectCallback* callback,
     if (bindAddr != anyAddress()) {
       int one = 1;
       if (::setsockopt(fd_, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) {
+        auto errnoCopy = errno;
         doClose();
         throw AsyncSocketException(
-          AsyncSocketException::NOT_OPEN,
-          "failed to setsockopt prior to bind on " + bindAddr.describe(),
-          errno);
+            AsyncSocketException::NOT_OPEN,
+            "failed to setsockopt prior to bind on " + bindAddr.describe(),
+            errnoCopy);
       }
 
       bindAddr.getAddress(&addrStorage);
 
       if (::bind(fd_, saddr, bindAddr.getActualSize()) != 0) {
+        auto errnoCopy = errno;
         doClose();
-        throw AsyncSocketException(AsyncSocketException::NOT_OPEN,
-                                  "failed to bind to async socket: " +
-                                  bindAddr.describe(),
-                                  errno);
+        throw AsyncSocketException(
+            AsyncSocketException::NOT_OPEN,
+            "failed to bind to async socket: " + bindAddr.describe(),
+            errnoCopy);
       }
     }
 
@@ -409,9 +421,11 @@ void AsyncSocket::connect(ConnectCallback* callback,
     for (const auto& opt: options) {
       int rv = opt.first.apply(fd_, opt.second);
       if (rv != 0) {
-        throw AsyncSocketException(AsyncSocketException::INTERNAL_ERROR,
-                                  withAddr("failed to set socket option"),
-                                  errno);
+        auto errnoCopy = errno;
+        throw AsyncSocketException(
+            AsyncSocketException::INTERNAL_ERROR,
+            withAddr("failed to set socket option"),
+            errnoCopy);
       }
     }
 
@@ -420,7 +434,8 @@ void AsyncSocket::connect(ConnectCallback* callback,
 
     rv = ::connect(fd_, saddr, address.getActualSize());
     if (rv < 0) {
-      if (errno == EINPROGRESS) {
+      auto errnoCopy = errno;
+      if (errnoCopy == EINPROGRESS) {
         // Connection in progress.
         if (timeout > 0) {
           // Start a timer in case the connection takes too long.
@@ -441,8 +456,10 @@ void AsyncSocket::connect(ConnectCallback* callback,
         }
         return;
       } else {
-        throw AsyncSocketException(AsyncSocketException::NOT_OPEN,
-                                  "connect failed (immediately)", errno);
+        throw AsyncSocketException(
+            AsyncSocketException::NOT_OPEN,
+            "connect failed (immediately)",
+            errnoCopy);
       }
     }
 
@@ -679,8 +696,11 @@ void AsyncSocket::writeImpl(WriteCallback* callback, const iovec* vec,
       bytesWritten = performWrite(vec, count, flags,
                                   &countWritten, &partialWritten);
       if (bytesWritten < 0) {
-        AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
-                               withAddr("writev failed"), errno);
+        auto errnoCopy = errno;
+        AsyncSocketException ex(
+            AsyncSocketException::INTERNAL_ERROR,
+            withAddr("writev failed"),
+            errnoCopy);
         return failWrite(__func__, callback, 0, ex);
       } else if (countWritten == count) {
         // We successfully wrote everything.
@@ -1355,8 +1375,11 @@ void AsyncSocket::handleRead() noexcept {
         return;
     } else if (bytesRead == READ_ERROR) {
       readErr_ = READ_ERROR;
-      AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
-                             withAddr("recv() failed"), errno);
+      auto errnoCopy = errno;
+      AsyncSocketException ex(
+          AsyncSocketException::INTERNAL_ERROR,
+          withAddr("recv() failed"),
+          errnoCopy);
       return failRead(__func__, ex);
     } else {
       assert(bytesRead == READ_EOF);
@@ -1416,8 +1439,11 @@ void AsyncSocket::handleWrite() noexcept {
   EventBase* originalEventBase = eventBase_;
   while (writeReqHead_ != nullptr && eventBase_ == originalEventBase) {
     if (!writeReqHead_->performWrite()) {
-      AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
-                             withAddr("writev() failed"), errno);
+      auto errnoCopy = errno;
+      AsyncSocketException ex(
+          AsyncSocketException::INTERNAL_ERROR,
+          withAddr("writev() failed"),
+          errnoCopy);
       return failWrite(__func__, ex);
     } else if (writeReqHead_->isComplete()) {
       // We finished this request
@@ -1591,9 +1617,11 @@ void AsyncSocket::handleConnect() noexcept {
   socklen_t len = sizeof(error);
   int rv = getsockopt(fd_, SOL_SOCKET, SO_ERROR, &error, &len);
   if (rv != 0) {
-    AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
-                           withAddr("error calling getsockopt() after connect"),
-                           errno);
+    auto errnoCopy = errno;
+    AsyncSocketException ex(
+        AsyncSocketException::INTERNAL_ERROR,
+        withAddr("error calling getsockopt() after connect"),
+        errnoCopy);
     VLOG(4) << "AsyncSocket::handleConnect(this=" << this << ", fd="
                << fd_ << " host=" << addr_.describe()
                << ") exception:" << ex.what();