Fix build on systems without HOST_NAME_MAX

Some operating systems such as FreeBSD don't define a HOST_NAME_MAX
macro. The portable approach to determine the real host name limit is
calling sysconf(_SC_HOST_NAME_MAX) so do that instead.

1 files changed, 9 insertions, 13 deletions

diff --git a/unix/x0vncserver/x0vncserver.cxx b/unix/x0vncserver/x0vncserver.cxx
index 89c9817e..29bc3d4c 100644
--- a/unix/x0vncserver/x0vncserver.cxx
+++ b/unix/x0vncserver/x0vncserver.cxx
@@ -71,29 +71,25 @@ BoolParameter localhostOnly("localhost",
 
 static const char* defaultDesktopName()
 {
-  static char* name = NULL;
-
-  char hostname[HOST_NAME_MAX + 1];
-  struct passwd* pwent;
-
-  size_t len;
-
-  delete [] name;
+  size_t host_max = sysconf(_SC_HOST_NAME_MAX);
+  if (host_max < 0)
+    return "";
 
-  if (gethostname(hostname, sizeof(hostname)) == -1)
+  std::vector<char> hostname(host_max + 1);
+  if (gethostname(hostname.data(), hostname.size()) == -1)
     return "";
 
-  pwent = getpwuid(getuid());
+  struct passwd* pwent = getpwuid(getuid());
   if (pwent == NULL)
     return "";
 
-  len = snprintf(NULL, 0, "%s@%s", pwent->pw_name, hostname);
+  size_t len = snprintf(NULL, 0, "%s@%s", pwent->pw_name, hostname.data());
   if (len < 0)
     return "";
 
-  name = new char[len + 1];
+  char* name = new char[len + 1];
 
-  snprintf(name, len + 1, "%s@%s", pwent->pw_name, hostname);
+  snprintf(name, len + 1, "%s@%s", pwent->pw_name, hostname.data());
 
   return name;
 }