Replace strdup() with M_StringDuplicate().

strdup() can theoretically fail and return NULL. This could lead to
a crash or undesirable behavior. Add M_StringDuplicate() which does
the same thing but exits with an error if a string cannot be
allocated.

This fixes #456. Thanks to Quasar for the suggestion.

3 files changed, 9 insertions, 8 deletions

diff --git a/src/setup/execute.c b/src/setup/execute.c
index 1fef6e44..bbb23c38 100644
--- a/src/setup/execute.c
+++ b/src/setup/execute.c
@@ -268,7 +268,7 @@ static char *GetFullExePath(const char *program)
 
     if (sep == NULL)
     {
-        result = strdup(program);
+        result = M_StringDuplicate(program);
     }
     else
     {
diff --git a/src/setup/multiplayer.c b/src/setup/multiplayer.c
index d833a495..f116ffb2 100644
--- a/src/setup/multiplayer.c
+++ b/src/setup/multiplayer.c
@@ -856,7 +856,7 @@ static void SelectQueryAddress(TXT_UNCAST_ARG(button),
     // Set address to connect to:
 
     free(connect_address);
-    connect_address = strdup(button->label);
+    connect_address = M_StringDuplicate(button->label);
 
     // Auto-choose IWAD if there is already a player connected.
 
@@ -1044,7 +1044,7 @@ void SetChatMacroDefaults(void)
     {
         if (chat_macros[i] == NULL)
         {
-            chat_macros[i] = strdup(defaults[i]);
+            chat_macros[i] = M_StringDuplicate(defaults[i]);
         }
     }
 }
@@ -1053,12 +1053,12 @@ void SetPlayerNameDefault(void)
 {
     if (net_player_name == NULL)
     {
-        net_player_name = strdup(getenv("USER"));
+        net_player_name = M_StringDuplicate(getenv("USER"));
     }
 
     if (net_player_name == NULL)
     {
-        net_player_name = strdup(getenv("USERNAME"));
+        net_player_name = M_StringDuplicate(getenv("USERNAME"));
     }
 
     // On Windows, environment variables are in OEM codepage
@@ -1073,7 +1073,7 @@ void SetPlayerNameDefault(void)
 
     if (net_player_name == NULL)
     {
-        net_player_name = strdup("player");
+        net_player_name = M_StringDuplicate("player");
     }
 }
 
diff --git a/src/setup/sound.c b/src/setup/sound.c
index 76fc0564..2b9bfcbb 100644
--- a/src/setup/sound.c
+++ b/src/setup/sound.c
@@ -20,6 +20,7 @@
 
 #include "textscreen.h"
 #include "m_config.h"
+#include "m_misc.h"
 
 #include "mode.h"
 #include "sound.h"
@@ -324,8 +325,8 @@ void BindSoundVariables(void)
         M_BindVariable("show_talk",       &show_talk);
     }
 
-    timidity_cfg_path = strdup("");
-    gus_patch_path = strdup("");
+    timidity_cfg_path = M_StringDuplicate("");
+    gus_patch_path = M_StringDuplicate("");
 
     // Default sound volumes - different games use different values.