From a177846044441ac24a461e27e29a41bf8070873b Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Tue, 31 Oct 2023 17:40:59 -0700
Subject: [PATCH] Better logging in recv_fds

---
 native/src/core/socket.cpp | 40 +++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/native/src/core/socket.cpp b/native/src/core/socket.cpp
index 57f70553b..a499b10a7 100644
--- a/native/src/core/socket.cpp
+++ b/native/src/core/socket.cpp
@@ -73,13 +73,27 @@ static void *recv_fds(int sockfd, char *cmsgbuf, size_t bufsz, int cnt) {
     };
 
     xrecvmsg(sockfd, &msg, MSG_WAITALL);
-    cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+    if (msg.msg_controllen != bufsz) {
+        LOGE("recv_fd: msg_flags = %d, msg_controllen(%zu) != %zu\n",
+             msg.msg_flags, msg.msg_controllen, bufsz);
+        return nullptr;
+    }
 
-    if (msg.msg_controllen != bufsz ||
-        cmsg == nullptr ||
-        cmsg->cmsg_len != CMSG_LEN(sizeof(int) * cnt) ||
-        cmsg->cmsg_level != SOL_SOCKET ||
-        cmsg->cmsg_type != SCM_RIGHTS) {
+    cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+    if (cmsg == nullptr) {
+        LOGE("recv_fd: cmsg == nullptr\n");
+        return nullptr;
+    }
+    if (cmsg->cmsg_len != CMSG_LEN(sizeof(int) * cnt)) {
+        LOGE("recv_fd: cmsg_len(%zu) != %zu\n", cmsg->cmsg_len, CMSG_LEN(sizeof(int) * cnt));
+        return nullptr;
+    }
+    if (cmsg->cmsg_level != SOL_SOCKET) {
+        LOGE("recv_fd: cmsg_level != SOL_SOCKET\n");
+        return nullptr;
+    }
+    if (cmsg->cmsg_type != SCM_RIGHTS) {
+        LOGE("recv_fd: cmsg_type != SCM_RIGHTS\n");
         return nullptr;
     }
 
@@ -92,8 +106,11 @@ vector<int> recv_fds(int sockfd) {
     // Peek fd count to allocate proper buffer
     int cnt;
     recv(sockfd, &cnt, sizeof(cnt), MSG_PEEK);
-    if (cnt == 0)
+    if (cnt == 0) {
+        // Consume data
+        recv(sockfd, &cnt, sizeof(cnt), MSG_WAITALL);
         return results;
+    }
 
     vector<char> cmsgbuf;
     cmsgbuf.resize(CMSG_SPACE(sizeof(int) * cnt));
@@ -109,6 +126,15 @@ vector<int> recv_fds(int sockfd) {
 }
 
 int recv_fd(int sockfd) {
+    // Peek fd count
+    int cnt;
+    recv(sockfd, &cnt, sizeof(cnt), MSG_PEEK);
+    if (cnt == 0) {
+        // Consume data
+        recv(sockfd, &cnt, sizeof(cnt), MSG_WAITALL);
+        return -1;
+    }
+
     char cmsgbuf[CMSG_SPACE(sizeof(int))];
 
     void *data = recv_fds(sockfd, cmsgbuf, sizeof(cmsgbuf), 1);