Problem: mkdtemp not available on all platforms

Solution: check for availability in autoconf and cmake, and if not
available fall back to random file name rather than random directory.

CMakeLists.txt

@@ -186,6 +186,10 @@ set (CMAKE_REQUIRED_INCLUDES sys/time.h)
 check_function_exists (gethrtime HAVE_GETHRTIME)
 set (CMAKE_REQUIRED_INCLUDES)
 
+set (CMAKE_REQUIRED_INCLUDES stdlib.h)
+check_function_exists (mkdtemp HAVE_MKDTEMP)
+set (CMAKE_REQUIRED_INCLUDES)
+
 add_definitions (-D_REENTRANT -D_THREAD_SAFE)
 add_definitions (-DZMQ_CUSTOM_PLATFORM_HPP)
 

builds/cmake/platform.hpp.in

@@ -12,6 +12,7 @@
 #cmakedefine HAVE_FORK
 #cmakedefine HAVE_CLOCK_GETTIME
 #cmakedefine HAVE_GETHRTIME
+#cmakedefine HAVE_MKDTEMP
 #cmakedefine ZMQ_HAVE_UIO
 
 #cmakedefine ZMQ_HAVE_EVENTFD

configure.ac

@@ -561,7 +561,7 @@ AC_LANG_POP([C++])
 
 # Checks for library functions.
 AC_TYPE_SIGNAL
-AC_CHECK_FUNCS(perror gettimeofday clock_gettime memset socket getifaddrs freeifaddrs fork posix_memalign)
+AC_CHECK_FUNCS(perror gettimeofday clock_gettime memset socket getifaddrs freeifaddrs fork posix_memalign mkdtemp)
 AC_CHECK_HEADERS([alloca.h])
 
 LIBZMQ_CHECK_SOCK_CLOEXEC([

src/ipc_listener.cpp

@@ -71,7 +71,8 @@ const char *zmq::ipc_listener_t::tmp_env_vars[] = {
   0  // Sentinel
 };
 
-int zmq::ipc_listener_t::create_wildcard_address(std::string& path_)
+int zmq::ipc_listener_t::create_wildcard_address(std::string& path_,
+        std::string& file_)
 {
     std::string tmp_path;
 
@@ -101,6 +102,7 @@ int zmq::ipc_listener_t::create_wildcard_address(std::string& path_)
     std::vector<char> buffer(tmp_path.length()+1);
     strcpy(buffer.data(), tmp_path.c_str());
 
+#ifdef HAVE_MKDTEMP
     // Create the directory.  POSIX requires that mkdtemp() creates the
     // directory with 0700 permissions, meaning the only possible race
     // with socket creation could be the same user.  However, since
@@ -112,6 +114,18 @@ int zmq::ipc_listener_t::create_wildcard_address(std::string& path_)
     }
 
     path_.assign(buffer.data());
+    file_.assign (path_ + "/socket");
+#else
+    // Silence -Wunused-parameter. #pragma and __attribute__((unused)) are not
+    // very portable unfortunately...
+    (void) path_;
+    int fd = mkstemp (buffer.data());
+    if (fd == -1)
+         return -1;
+    ::close (fd);
+
+    file_.assign (buffer.data());
+#endif
 
     return 0;
 }
@@ -201,15 +215,9 @@ int zmq::ipc_listener_t::set_address (const char *addr_)
 
     //  Allow wildcard file
     if (addr [0] == '*') {
-        std::string tmp_path;
-
-        if ( create_wildcard_address(tmp_path) < 0 ) {
+        if ( create_wildcard_address(tmp_socket_dirname, addr) < 0 ) {
             return -1;
         }
-
-        tmp_socket_dirname.assign(tmp_path);
-
-        addr.assign (tmp_path + "/socket");
     }
 
     //  Get rid of the file associated with the UNIX domain socket that

src/ipc_listener.hpp

@@ -74,7 +74,8 @@ namespace zmq
         int close ();
 
         // Create wildcard path address
-        static int create_wildcard_address(std::string& path_);
+        static int create_wildcard_address(std::string& path_,
+                std::string& file_);
 
         //  Filter new connections if the OS provides a mechanism to get
         //  the credentials of the peer process.  Called from accept().