libc: common: Add support for malloc stats

If malloc is enabled in common libc, add support for malloc stats using
the mallinfo API.

Signed-off-by: Chaitanya Tata <[email protected]>

Author: krish2718

lib/libc/common/source/stdlib/malloc.c

@@ -5,6 +5,7 @@
  */
 
 #include <stdlib.h>
+#include <malloc.h>
 #include <zephyr/kernel.h>
 #include <zephyr/init.h>
 #include <errno.h>
@@ -229,6 +230,38 @@ void free(void *ptr)
 	(void) sys_mutex_unlock(&z_malloc_heap_mutex);
 }
 
+#if __GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 33)
+struct mallinfo mallinfo(void)
+#else
+struct mallinfo2 mallinfo2(void)
+#endif /* __GLIBC__ < 2 && (__GLIBC__ == 2 && __GLIBC_MINOR__ < 33) */
+{
+#if __GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 33)
+	struct mallinfo info = { 0 };
+#else
+	struct mallinfo2 info = { 0 };
+#endif /* __GLIBC__ < 2 && (__GLIBC__ == 2 && __GLIBC_MINOR__ < 33) */
+#ifdef CONFIG_SYS_HEAP_RUNTIME_STATS
+	struct sys_memory_stats stats;
+	int ret = sys_heap_runtime_stats_get(&z_malloc_heap, &stats);
+
+	if (ret != 0) {
+		LOG_ERR("Failed to get heap stats");
+		return info;
+	}
+
+	info.arena = stats.free_bytes + stats.allocated_bytes;
+	info.fordblks = stats.free_bytes;
+	info.uordblks = stats.allocated_bytes;
+	info.usmblks = stats.max_allocated_bytes;
+#else
+	ARG_UNUSED(info);
+	LOG_ERR("CONFIG_SYS_HEAP_RUNTIME_STATS is not enabled");
+#endif
+
+	return info;
+}
+
 SYS_INIT(malloc_prepare, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
 #else /* No malloc arena */
 void *malloc(size_t size)
@@ -251,6 +284,15 @@ void *realloc(void *ptr, size_t size)
 	ARG_UNUSED(ptr);
 	return malloc(size);
 }
+
+struct mallinfo2 mallinfo2(void)
+{
+	struct mallinfo2 info = { 0 };
+
+	LOG_ERR("CONFIG_COMMON_LIBC_MALLOC_ARENA_SIZE is 0");
+
+	return info;
+}
 #endif /* else no malloc arena */
 
 #endif /* CONFIG_COMMON_LIBC_MALLOC */

lib/libc/minimal/include/malloc.h

@@ -0,0 +1,35 @@
+/* malloc.h */
+
+/*
+ * Copyright (c) 2023 - Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_LIB_LIBC_MINIMAL_INCLUDE_MALLOC_H_
+#define ZEPHYR_LIB_LIBC_MINIMAL_INCLUDE_MALLOC_H_
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct mallinfo2 {
+	size_t arena;    /* total space allocated from system */
+	size_t ordblks;  /* number of non-inuse chunks */
+	size_t smblks;   /* unused -- always zero */
+	size_t hblks;    /* number of mmapped regions */
+	size_t hblkhd;   /* total space in mmapped regions */
+	size_t usmblks;  /* unused -- always zero */
+	size_t fsmblks;  /* unused -- always zero */
+	size_t uordblks; /* total allocated space */
+	size_t fordblks; /* total non-inuse space */
+	size_t keepcost; /* top-most, releasable (via malloc_trim) space */
+};
+
+struct mallinfo2 mallinfo2(void);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* ZEPHYR_LIB_LIBC_MINIMAL_INCLUDE_MALLOC_H_ */