1 files changed, 123 insertions, 0 deletions
diff --git a/src/basic/memory-util.h b/src/basic/memory-util.h
new file mode 100644
index 0000000..6e3280b
--- /dev/null
+++ b/src/basic/memory-util.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <inttypes.h>
+#include <malloc.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "alloc-util.h"
+#include "macro.h"
+
+size_t page_size(void) _pure_;
+#define PAGE_ALIGN(l) ALIGN_TO((l), page_size())
+#define PAGE_ALIGN_DOWN(l) ((l) & ~(page_size() - 1))
+#define PAGE_OFFSET(l) ((l) & (page_size() - 1))
+
+/* Normal memcpy() requires src to be nonnull. We do nothing if n is 0. */
+static inline void *memcpy_safe(void *dst, const void *src, size_t n) {
+        if (n == 0)
+                return dst;
+        assert(src);
+        return memcpy(dst, src, n);
+}
+
+/* Normal mempcpy() requires src to be nonnull. We do nothing if n is 0. */
+static inline void *mempcpy_safe(void *dst, const void *src, size_t n) {
+        if (n == 0)
+                return dst;
+        assert(src);
+        return mempcpy(dst, src, n);
+}
+
+/* Normal memcmp() requires s1 and s2 to be nonnull. We do nothing if n is 0. */
+static inline int memcmp_safe(const void *s1, const void *s2, size_t n) {
+        if (n == 0)
+                return 0;
+        assert(s1);
+        assert(s2);
+        return memcmp(s1, s2, n);
+}
+
+/* Compare s1 (length n1) with s2 (length n2) in lexicographic order. */
+static inline int memcmp_nn(const void *s1, size_t n1, const void *s2, size_t n2) {
+        return memcmp_safe(s1, s2, MIN(n1, n2))
+            ?: CMP(n1, n2);
+}
+
+#define memzero(x,l)                                            \
+        ({                                                      \
+                size_t _l_ = (l);                               \
+                if (_l_ > 0)                                    \
+                        memset(x, 0, _l_);                      \
+        })
+
+#define zero(x) (memzero(&(x), sizeof(x)))
+
+bool memeqbyte(uint8_t byte, const void *data, size_t length);
+
+#define memeqzero(data, length) memeqbyte(0x00, data, length)
+
+#define eqzero(x) memeqzero(x, sizeof(x))
+
+static inline void *mempset(void *s, int c, size_t n) {
+        memset(s, c, n);
+        return (uint8_t*)s + n;
+}
+
+/* Normal memmem() requires haystack to be nonnull, which is annoying for zero-length buffers */
+static inline void *memmem_safe(const void *haystack, size_t haystacklen, const void *needle, size_t needlelen) {
+
+        if (needlelen <= 0)
+                return (void*) haystack;
+
+        if (haystacklen < needlelen)
+                return NULL;
+
+        assert(haystack);
+        assert(needle);
+
+        return memmem(haystack, haystacklen, needle, needlelen);
+}
+
+static inline void *mempmem_safe(const void *haystack, size_t haystacklen, const void *needle, size_t needlelen) {
+        const uint8_t *p;
+
+        p = memmem_safe(haystack, haystacklen, needle, needlelen);
+        if (!p)
+                return NULL;
+
+        return (uint8_t*) p + needlelen;
+}
+
+#if HAVE_EXPLICIT_BZERO
+static inline void* explicit_bzero_safe(void *p, size_t l) {
+        if (l > 0)
+                explicit_bzero(p, l);
+
+        return p;
+}
+#else
+void *explicit_bzero_safe(void *p, size_t l);
+#endif
+
+static inline void* erase_and_free(void *p) {
+        size_t l;
+
+        if (!p)
+                return NULL;
+
+        l = MALLOC_SIZEOF_SAFE(p);
+        explicit_bzero_safe(p, l);
+        return mfree(p);
+}
+
+static inline void erase_and_freep(void *p) {
+        erase_and_free(*(void**) p);
+}
+
+/* Use with _cleanup_ to erase a single 'char' when leaving scope */
+static inline void erase_char(char *p) {
+        explicit_bzero_safe(p, sizeof(char));
+}