Replace all snprintf() calls with M_snprintf().

The Windows API has an _snprintf function that is not the same as
Unix's snprintf(): if the string is truncated then no trailing NUL
character is appended. This makes the function unsafe. Define a
replacement/wrapper called M_snprintf that works the same but always
appends a trailing NUL, for safety on Windows and other OSes that
behave like this.

Do the same thing for vsnprintf(), and update HACKING to list
snprintf/vsnprintf as forbidden functions. This fixes #375;
thanks to Quasar for pointing out the different behavior of these
functions.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/strife/p_saveg.c b/src/strife/p_saveg.c
index 47fb7e8c..2f59c732 100644
--- a/src/strife/p_saveg.c
+++ b/src/strife/p_saveg.c
@@ -32,6 +32,7 @@
 #include "deh_main.h"
 #include "i_system.h"
 #include "z_zone.h"
+#include "m_misc.h"
 #include "p_local.h"
 #include "p_saveg.h"
 
@@ -80,7 +81,7 @@ char *P_SaveGameFile(int slot)
 
     DEH_snprintf(basename, 32, SAVEGAMENAME "%d.dsg", slot);
 
-    snprintf(filename, filename_size, "%s%s", savegamedir, basename);
+    M_snprintf(filename, filename_size, "%s%s", savegamedir, basename);
 
     return filename;
 }
@@ -1609,7 +1610,7 @@ void P_WriteSaveGameHeader(char *description)
     */
 
     memset (name,0,sizeof(name)); 
-    snprintf(name, sizeof(name), "ver %i", STRIFE_VERSION);
+    M_snprintf(name, sizeof(name), "ver %i", STRIFE_VERSION);
 
     for (i=0; i<VERSIONSIZE; ++i)
         saveg_write8(name[i]);
@@ -1649,7 +1650,7 @@ boolean P_ReadSaveGameHeader(void)
         read_vcheck[i] = saveg_read8();
 
     memset (vcheck,0,sizeof(vcheck));
-    snprintf(vcheck, sizeof(vcheck), "ver %i", STRIFE_VERSION);
+    M_snprintf(vcheck, sizeof(vcheck), "ver %i", STRIFE_VERSION);
     if (strcmp(read_vcheck, vcheck) != 0)
         return false;                       // bad version