1 files changed, 108 insertions, 0 deletions
diff --git a/src/basic/alloc-util.c b/src/basic/alloc-util.c
new file mode 100644
index 0000000..6063943
--- /dev/null
+++ b/src/basic/alloc-util.c
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <malloc.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "alloc-util.h"
+#include "macro.h"
+#include "memory-util.h"
+
+void* memdup(const void *p, size_t l) {
+        void *ret;
+
+        assert(l == 0 || p);
+
+        ret = malloc(l ?: 1);
+        if (!ret)
+                return NULL;
+
+        return memcpy_safe(ret, p, l);
+}
+
+void* memdup_suffix0(const void *p, size_t l) {
+        void *ret;
+
+        assert(l == 0 || p);
+
+        /* The same as memdup() but place a safety NUL byte after the allocated memory */
+
+        if (_unlikely_(l == SIZE_MAX)) /* prevent overflow */
+                return NULL;
+
+        ret = malloc(l + 1);
+        if (!ret)
+                return NULL;
+
+        ((uint8_t*) ret)[l] = 0;
+        return memcpy_safe(ret, p, l);
+}
+
+void* greedy_realloc(
+                void **p,
+                size_t need,
+                size_t size) {
+
+        size_t a, newalloc;
+        void *q;
+
+        assert(p);
+
+        /* We use malloc_usable_size() for determining the current allocated size. On all systems we care
+         * about this should be safe to rely on. Should there ever arise the need to avoid relying on this we
+         * can instead locally fall back to realloc() on every call, rounded up to the next exponent of 2 or
+         * so. */
+
+        if (*p && (size == 0 || (MALLOC_SIZEOF_SAFE(*p) / size >= need)))
+                return *p;
+
+        if (_unlikely_(need > SIZE_MAX/2)) /* Overflow check */
+                return NULL;
+        newalloc = need * 2;
+
+        if (size_multiply_overflow(newalloc, size))
+                return NULL;
+        a = newalloc * size;
+
+        if (a < 64) /* Allocate at least 64 bytes */
+                a = 64;
+
+        q = realloc(*p, a);
+        if (!q)
+                return NULL;
+
+        return *p = q;
+}
+
+void* greedy_realloc0(
+                void **p,
+                size_t need,
+                size_t size) {
+
+        size_t before, after;
+        uint8_t *q;
+
+        assert(p);
+
+        before = MALLOC_SIZEOF_SAFE(*p); /* malloc_usable_size() will return 0 on NULL input, as per docs */
+
+        q = greedy_realloc(p, need, size);
+        if (!q)
+                return NULL;
+
+        after = MALLOC_SIZEOF_SAFE(q);
+
+        if (size == 0) /* avoid division by zero */
+                before = 0;
+        else
+                before = (before / size) * size; /* Round down */
+
+        if (after > before)
+                memzero(q + before, after - before);
+
+        return q;
+}
+
+void *expand_to_usable(void *ptr, size_t newsize _unused_) {
+        return ptr;
+}