List:       libt2n-git
Subject:    C++ inter-process communication library branch, master, updated. v0.7-8-g6f59dcf
From:       libt2n-git () developer ! intra2net ! com
Date:       2022-03-16 8:13:12
Message-ID: 20220316081312.885692782B9 () developer ! intra2net ! com
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The branch, master has been updated
       via  6f59dcf596103d0bc69be841627cd9926faa4139 (commit)
      from  a63e08b83794273da3840e0b8bf15bf0085fe3c4 (commit)


- Log -----------------------------------------------------------------
commit 6f59dcf596103d0bc69be841627cd9926faa4139
Author: Thomas Jarosch <thomas.jarosch@intra2net.com>
Date:   Wed Mar 16 09:13:00 2022 +0100

    Replace socket_handler::fill_buffer() recursion with loop (#8389)
    
    The loop is more stack friendly and also limited to 32 iterations
    to prevent starvation of other connections.
    
    Remove bogus "try_again" logic: The flag was set in "nbytes < 0",
    but checked when "nbytes == 0" down below -> it probably never worked,
    at least not how it was designed to work.

-----------------------------------------------------------------------

Summary of changes:
 src/socket_handler.cpp |   72 ++++++++++++++++++++++++++----------------------
 1 files changed, 39 insertions(+), 33 deletions(-)

diff --git a/src/socket_handler.cpp b/src/socket_handler.cpp
index 13e5a45..0cc5036 100644
--- a/src/socket_handler.cpp
+++ b/src/socket_handler.cpp
@@ -236,49 +236,55 @@ bool socket_handler::fill_buffer(std::string& buffer, long long \
                usec_timeout, lo
 */
 bool socket_handler::fill_buffer(std::string& buffer)
 {
-    bool try_again=false;
-
     char socket_buffer[recv_buffer_size];
 
-    int nbytes = read (sock, socket_buffer, recv_buffer_size);
+    const int loop_max = 32;            /* limit is 32 * (default) 2048 bytes -> \
65536 bytes in one go */ +    int loop_count = 0;
 
-    if (nbytes < 0)
+    bool read_something = false;
+    while (loop_count < loop_max)
     {
-        if (errno == EAGAIN)
-            return false;                // no data was waiting
-        else if (errno == EINTR)
+        const int nbytes = read(sock, socket_buffer, recv_buffer_size);
+
+        if (nbytes < 0)
         {
-            // interrupted, try again
-            LOGSTREAM(debug,"EINTR received on read(), trying again");
-            try_again=true;
+            if (errno == EAGAIN)
+                return read_something;                // no (more) data was waiting
+            else if (errno == EINTR)
+            {
+                // interrupted, try again
+                LOGSTREAM(debug, "EINTR received on read(), trying again");
+            } else
+                EXCEPTIONSTREAM(error, t2n_transfer_error, "error reading from \
socket : " << strerror(errno));  }
-        else
-            EXCEPTIONSTREAM(error,t2n_transfer_error,"error reading from socket : " \
                << strerror(errno));
-    }
 
-    // End-of-file
-    if (nbytes == 0 && !try_again)
-    {
-        LOGSTREAM(debug,"0 bytes received on read(), closing connection");
-        close();
-        return false;
-    }
+        // End-of-file
+        if (nbytes == 0)
+        {
+            LOGSTREAM(debug, "0 bytes received on read(), closing connection");
+            close();
+            return read_something;
+        }
 
-    // Data read -> store it
-    if (nbytes > 0)
-    {
-        buffer.append(socket_buffer,nbytes);
-        LOGSTREAM(debug,nbytes << " bytes read");
-    }
+        // Data read -> store it
+        if (nbytes > 0)
+        {
+            buffer.append(socket_buffer, nbytes);
+            LOGSTREAM(debug, nbytes << " bytes read");
+            read_something = true;
+        }
 
-    // more data waiting -> recurse
-    if (data_waiting(0))
-        fill_buffer(buffer);
+        // more data waiting -> loop once more (up to loop_max)
+        if (data_waiting(0))
+        {
+            ++loop_count;
+        } else
+        {
+            break;
+        }
+    }
 
-    if (nbytes > 0)
-        return true;
-    else
-        return false;
+    return read_something;
 }
 
 /// writes raw data to the socket. Don't use directly, use the write() function \
provided by the 


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C++ inter-process communication library

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