sprintf deprecation error failing build on macOS

[ghmanoj]

Issue description

Build is failing in macOS 13.1

Environment

OS: macOS 13.1
Build Environment:
Apple clang version 14.0.0 (clang-1400.0.29.202)
Target: x86_64-apple-darwin22.2.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

• libzmq version (commit hash if unreleased): dfbfc59
• OS: macOS 13.1

Minimal test code / Steps to reproduce the issue

Run the following command after git clone:

1. ./autogen.sh
2. ./configure
3. make

What's the actual result? (include assertion message & call stack if applicable)

make[1]: Nothing to be done for `all'.
CXX src/libzmq_la-tcp_address.lo
src/tcp_address.cpp:132:12: error: 'sprintf' is deprecated: This function is provided for compatibility reasons only. Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead. [-Werror,-Wdeprecated-declarations]
pos += sprintf (pos, "%d", ntohs (port_));
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:188:1: note: 'sprintf' has been explicitly marked deprecated here
__deprecated_msg("This function is provided for compatibility reasons only. Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead.")
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/cdefs.h:215:48: note: expanded from macro '__deprecated_msg'
#define __deprecated_msg(_msg) attribute((deprecated(_msg)))
^
1 error generated.
make[1]: *** [src/libzmq_la-tcp_address.lo] Error 1
make: *** [all-recursive] Error 1

What's the expected result?

Build should pass

[ghmanoj]

The patch below fixes the build. It replaces the sprintf(...) with snprintf(...) but not sure this solution is optimal or not?

diff --git a/src/tcp_address.cpp b/src/tcp_address.cpp
index bdda66a2..fcce9c03 100644
--- a/src/tcp_address.cpp
+++ b/src/tcp_address.cpp
@@ -129,7 +129,8 @@ static std::string make_address_string (const char *hbuf_,
     pos += hbuf_len;
     memcpy (pos, ipv6_suffix_, sizeof ipv6_suffix_ - 1);
     pos += sizeof ipv6_suffix_ - 1;
-    pos += sprintf (pos, "%d", ntohs (port_));
+    pos += snprintf (pos, sizeof(pos), "%d", ntohs (port_));
+    
     return std::string (buf, pos - buf);
 }

diff --git a/src/udp_engine.cpp b/src/udp_engine.cpp
index d09bfe16..0b097f1f 100644
--- a/src/udp_engine.cpp
+++ b/src/udp_engine.cpp
@@ -368,7 +368,8 @@ void zmq::udp_engine_t::sockaddr_to_msg (zmq::msg_t *msg_,
 
     char port[6];
     const int port_len =
-      sprintf (port, "%d", static_cast<int> (ntohs (addr_->sin_port)));
+      snprintf (port, sizeof (port), "%d", static_cast<int> (ntohs (addr_->sin_port)));
+
     zmq_assert (port_len > 0);
 
     const size_t name_len = strlen (name);

diff --git a/tests/testutil.cpp b/tests/testutil.cpp
index 5306aff9..f9f1eb0c 100644
--- a/tests/testutil.cpp
+++ b/tests/testutil.cpp
@@ -518,7 +518,7 @@ fd_t bind_socket_resolve_port (const char *address_,
         addr_len = sizeof (struct sockaddr_storage);
         TEST_ASSERT_SUCCESS_RAW_ERRNO (
           getsockname (s_pre, (struct sockaddr *) &addr, &addr_len));
-        sprintf (my_endpoint_, "%s://%s:%u",
+        snprintf (my_endpoint_, sizeof(my_endpoint_), "%s://%s:%u",
                  protocol_ == IPPROTO_TCP   ? "tcp"
                  : protocol_ == IPPROTO_UDP ? "udp"
                  : protocol_ == IPPROTO_WSS ? "wss"

[nieder]

@ghmanoj If you surround the code with lines with three backticks `,
then the formatting will be easier to read.

So like

```diff
first line
-Code diff
+Code diff
bar
```

Looks like

 first line
-Code diff
+Code diff
 bar

[sphaero]

Seeing the same error on latest MacOS.

  CXX      src/libzmq_la-tcp_address.lo
src/tcp_address.cpp:132:12: error: 'sprintf' is deprecated: This function is provided for compatibility reasons only.  Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead. [-Werror,-Wdeprecated-declarations]
    pos += sprintf (pos, "%d", ntohs (port_));
           ^
/Applications/Xcode_14.2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:188:1: note: 'sprintf' has been explicitly marked deprecated here
__deprecated_msg("This function is provided for compatibility reasons only.  Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead.")
^
/Applications/Xcode_14.2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/cdefs.h:215:48: note: expanded from macro '__deprecated_msg'
        #define __deprecated_msg(_msg) __attribute__((__deprecated__(_msg)))
                                                      ^
1 error generated.

@ghmanoj can you send a pull request?