New memory allocators that exit on OOM and handle multiplication overflow

Every place that does a regular malloc/calloc and aborts on failure
should use spice_malloc/spice_mallo0 instead, which is leaner and cleaner.

Allocations of dynamically sized arrays can use g_malloc_n or g_new etc
which correctly handle multiplication overflow if some of the arguments
are not trusted.

1 files changed, 82 insertions, 0 deletions

diff --git a/common/mem.h b/common/mem.h
new file mode 100644
index 0000000..f5fab20
--- /dev/null
+++ b/common/mem.h
@@ -0,0 +1,82 @@
+/* -*- Mode: C; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+   Copyright (C) 2010 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _H_MEM
+#define _H_MEM
+
+#include <stdlib.h>
+#include <spice/macros.h>
+
+char *spice_strdup(const char *str) SPICE_GNUC_MALLOC;
+void *spice_memdup(const void *mem, size_t n_bytes) SPICE_GNUC_MALLOC;
+void *spice_malloc(size_t n_bytes) SPICE_GNUC_MALLOC SPICE_GNUC_ALLOC_SIZE(1);
+void *spice_malloc0(size_t n_bytes) SPICE_GNUC_MALLOC SPICE_GNUC_ALLOC_SIZE(1);
+void *spice_realloc(void *mem, size_t n_bytes) SPICE_GNUC_WARN_UNUSED_RESULT;
+void *spice_malloc_n(size_t n_blocks, size_t n_block_bytes) SPICE_GNUC_MALLOC SPICE_GNUC_ALLOC_SIZE2(1,2);
+void *spice_malloc_n_m(size_t n_blocks, size_t n_block_bytes, size_t extra_size) SPICE_GNUC_MALLOC;
+void *spice_malloc0_n(size_t n_blocks, size_t n_block_bytes) SPICE_GNUC_MALLOC SPICE_GNUC_ALLOC_SIZE2(1,2);
+void *spice_realloc_n(void *mem, size_t n_blocks, size_t n_block_bytes) SPICE_GNUC_WARN_UNUSED_RESULT;
+
+/* Optimise: avoid the call to the (slower) _n function if we can
+ * determine at compile-time that no overflow happens.
+ */
+#if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
+#  define _SPICE_NEW(struct_type, n_structs, func)        \
+    (struct_type *) (__extension__ ({                     \
+        size_t __n = (size_t) (n_structs);                \
+        size_t __s = sizeof (struct_type);                \
+        void *__p;                                        \
+        if (__s == 1)                                     \
+            __p = spice_##func (__n);                     \
+        else if (__builtin_constant_p (__n) &&            \
+                 __n <= SIZE_MAX / __s)                   \
+            __p = spice_##func (__n * __s);               \
+        else                                              \
+            __p = spice_##func##_n (__n, __s);            \
+        __p;                                              \
+    }))
+#  define _SPICE_RENEW(struct_type, mem, n_structs, func) \
+    (struct_type *) (__extension__ ({                             \
+        size_t __n = (size_t) (n_structs);                \
+        size_t __s = sizeof (struct_type);                \
+        void *__p = (void *) (mem);                       \
+        if (__s == 1)                                     \
+            __p = spice_##func (__p, __n);                \
+        else if (__builtin_constant_p (__n) &&            \
+                 __n <= SIZE_MAX / __s)                   \
+            __p = spice_##func (__p, __n * __s);          \
+        else                                              \
+            __p = spice_##func##_n (__p, __n, __s);       \
+        __p;                                              \
+    }))
+#else
+
+/* Unoptimised version: always call the _n() function. */
+
+#define _SPICE_NEW(struct_type, n_structs, func)                        \
+    ((struct_type *) spice_##func##_n ((n_structs), sizeof (struct_type)))
+#define _SPICE_RENEW(struct_type, mem, n_structs, func)                 \
+    ((struct_type *) spice_##func##_n (mem, (n_structs), sizeof (struct_type)))
+
+#endif
+
+#define spice_new(struct_type, n_structs) _SPICE_NEW(struct_type, n_structs, malloc)
+#define spice_new0(struct_type, n_structs) _SPICE_NEW(struct_type, n_structs, malloc0)
+#define spice_renew(struct_type, mem, n_structs) _SPICE_RENEW(struct_type, mem, n_structs, realloc)
+
+#endif