X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/blobdiff_plain/dcbde23605bb045df116a1dd522d4ddb4d9288fa..5462f4596108c4309fb69b4e57aa1e59d7100908:/puttymem.h

diff --git a/puttymem.h b/puttymem.h
index ba4fd0ed..941aded3 100644
--- a/puttymem.h
+++ b/puttymem.h
@@ -5,20 +5,48 @@
 #ifndef PUTTY_PUTTYMEM_H
 #define PUTTY_PUTTYMEM_H
 
+#include <stddef.h>		       /* for size_t */
+#include <string.h>		       /* for memcpy() */
+
+
 /* #define MALLOC_LOG  do this if you suspect putty of leaking memory */
 #ifdef MALLOC_LOG
-#define smalloc(z) (mlog(__FILE__,__LINE__), safemalloc(z))
-#define srealloc(y,z) (mlog(__FILE__,__LINE__), saferealloc(y,z))
+#define smalloc(z) (mlog(__FILE__,__LINE__), safemalloc(z,1))
+#define snmalloc(z,s) (mlog(__FILE__,__LINE__), safemalloc(z,s))
+#define srealloc(y,z) (mlog(__FILE__,__LINE__), saferealloc(y,z,1))
+#define snrealloc(y,z,s) (mlog(__FILE__,__LINE__), saferealloc(y,z,s))
 #define sfree(z) (mlog(__FILE__,__LINE__), safefree(z))
 void mlog(char *, int);
 #else
-#define smalloc safemalloc
-#define srealloc saferealloc
+#define smalloc(z) safemalloc(z,1)
+#define snmalloc safemalloc
+#define srealloc(y,z) saferealloc(y,z,1)
+#define snrealloc saferealloc
 #define sfree safefree
 #endif
 
-void *safemalloc(size_t);
-void *saferealloc(void *, size_t);
+void *safemalloc(size_t, size_t);
+void *saferealloc(void *, size_t, size_t);
 void safefree(void *);
 
+/*
+ * Direct use of smalloc within the code should be avoided where
+ * possible, in favour of these type-casting macros which ensure
+ * you don't mistakenly allocate enough space for one sort of
+ * structure and assign it to a different sort of pointer.
+ *
+ * The nasty trick in sresize with sizeof arranges for the compiler,
+ * in passing, to type-check the expression ((type *)0 == (ptr)), i.e.
+ * to type-check that the input pointer is a pointer to the correct
+ * type. The construction sizeof(stuff) ? (b) : (b) looks like a
+ * violation of the first principle of safe macros, but in fact it's
+ * OK - although it _expands_ the macro parameter more than once, it
+ * only _evaluates_ it once, so it's still side-effect safe.
+ */
+#define snew(type) ((type *)snmalloc(1, sizeof(type)))
+#define snewn(n, type) ((type *)snmalloc((n), sizeof(type)))
+#define sresize(ptr, n, type)                                           \
+    ((type *)snrealloc(sizeof((type *)0 == (ptr)) ? (ptr) : (ptr),      \
+                       (n), sizeof(type)))
+
 #endif