Update and restore malloc-simple. Slow as molasses, but trivially

simple and releases memory immediately when asked to do so.
 -Erik

libc/stdlib/malloc-simple/Makefile

@@ -0,0 +1,44 @@
+# Makefile for uClibc
+#
+# Copyright (C) 2000-2003 Erik Andersen <andersen@uclibc.org>
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU Library 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 Library General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Library General Public License
+# along with this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+# Derived in part from the Linux-8086 C library, the GNU C Library, and several
+# other sundry sources.  Files within this library are copyright by their
+# respective copyright holders.
+
+TOPDIR=../../../
+include $(TOPDIR)Rules.mak
+
+MSRC=alloc.c
+MOBJ=malloc.o realloc.o free.o calloc.o memalign.o
+OBJS=$(MOBJ)
+
+
+all: $(OBJS) $(LIBC)
+
+$(LIBC): ar-target
+
+ar-target: $(OBJS)
+	$(AR) $(ARFLAGS) $(LIBC) $(OBJS)
+
+$(MOBJ): $(MSRC)
+	$(CC) $(CFLAGS) -DL_$* $< -c -o $*.o
+	$(STRIPTOOL) -x -R .note -R .comment $*.o
+
+clean:
+	rm -f *.[oa] *~ core
+

libc/stdlib/malloc-simple/alloc.c

@@ -0,0 +1,189 @@
+/* alloc.c
+ *
+ * Written by Erik Andersen <andersee@debian.org>
+ * LGPLv2
+ *
+ * Parts of the memalign code were stolen from malloc-930716.
+ */
+
+#include <features.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+
+#ifdef L_malloc
+void *malloc(size_t size)
+{
+    void *result;
+
+    if (unlikely(size == 0)) {
+#if defined(__MALLOC_GLIBC_COMPAT__)
+	size++;
+#else
+	/* Some programs will call malloc (0).  Lets be strict and return NULL */
+	return 0;
+#endif
+    }
+
+#ifdef __UCLIBC_HAS_MMU__
+    result = mmap((void *) 0, size + sizeof(size_t), PROT_READ | PROT_WRITE,
+	    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+    if (result == MAP_FAILED)
+	return 0;
+    * (size_t *) result = size;
+    return(result + sizeof(size_t));
+#else
+    result = mmap((void *) 0, size, PROT_READ | PROT_WRITE,
+	    MAP_SHARED | MAP_ANONYMOUS, 0, 0);
+    if (result == MAP_FAILED)
+	return 0;
+    return(result);
+#endif
+}
+#endif
+
+#ifdef L_calloc
+void *calloc(size_t num, size_t size)
+{
+    void *ptr = malloc(num * size);
+    if (ptr)
+	memset(ptr, 0, num * size);
+    return ptr;
+}
+#endif
+
+#ifdef L_realloc
+void *realloc(void *ptr, size_t size)
+{
+    void *newptr = NULL;
+
+    if (!ptr)
+	return malloc(size);
+    if (!size) {
+	free(ptr);
+	return malloc(0);
+    }
+
+    newptr = malloc(size);
+    if (newptr) {
+	memcpy(newptr, ptr,
+#ifdef __UCLIBC_HAS_MMU__
+		*((size_t *) (ptr - sizeof(size_t)))
+#else
+		size
+#endif
+	      );
+	free(ptr);
+    }
+    return newptr;
+}
+#endif
+
+#ifdef L_free
+extern int weak_function __libc_free_aligned(void *ptr);
+void free(void *ptr)
+{
+    if (ptr == NULL)
+	return;
+    if (unlikely(__libc_free_aligned!=NULL)) {
+	if (__libc_free_aligned(ptr)) {
+	    return;
+	}
+    }
+#ifdef __UCLIBC_HAS_MMU__
+    ptr -= sizeof(size_t);
+    munmap(ptr, * (size_t *) ptr + sizeof(size_t));
+#else
+    munmap(ptr, 0);
+#endif
+}
+#endif
+
+#ifdef L_memalign
+#ifdef __UCLIBC_HAS_THREADS__
+#include <pthread.h>
+extern pthread_mutex_t __malloclock;
+# define LOCK	__pthread_mutex_lock(&__malloclock)
+# define UNLOCK	__pthread_mutex_unlock(&__malloclock);
+#else
+# define LOCK
+# define UNLOCK
+#endif
+
+/* List of blocks allocated with memalign or valloc */
+struct alignlist
+{
+    struct alignlist *next;
+    __ptr_t aligned;	/* The address that memaligned returned.  */
+    __ptr_t exact;	/* The address that malloc returned.  */
+};
+struct alignlist *_aligned_blocks;
+
+/* Return memory to the heap. */
+int __libc_free_aligned(void *ptr)
+{
+    struct alignlist *l;
+
+    if (ptr == NULL)
+	return 0;
+
+    LOCK;
+    for (l = _aligned_blocks; l != NULL; l = l->next) {
+	if (l->aligned == ptr) {
+	    /* Mark the block as free */
+	    l->aligned = NULL;
+	    ptr = l->exact;
+#ifdef __UCLIBC_HAS_MMU__
+	    ptr -= sizeof(size_t);
+	    munmap(ptr, * (size_t *) ptr + sizeof(size_t));
+#else
+	    munmap(ptr, 0);
+#endif
+	    return 1;
+	}
+    }
+    UNLOCK;
+    return 0;
+}
+void * memalign (size_t alignment, size_t size)
+{
+    void * result;
+    unsigned long int adj;
+
+    result = malloc (size + alignment - 1);
+    if (result == NULL)
+	return NULL;
+    adj = (unsigned long int) ((unsigned long int) ((char *) result -
+		(char *) NULL)) % alignment;
+    if (adj != 0)
+    {
+	struct alignlist *l;
+	LOCK;
+	for (l = _aligned_blocks; l != NULL; l = l->next)
+	    if (l->aligned == NULL)
+		/* This slot is free.  Use it.  */
+		break;
+	if (l == NULL)
+	{
+	    l = (struct alignlist *) malloc (sizeof (struct alignlist));
+	    if (l == NULL) {
+		free(result);
+		UNLOCK;
+		return NULL;
+	    }
+	    l->next = _aligned_blocks;
+	    _aligned_blocks = l;
+	}
+	l->exact = result;
+	result = l->aligned = (char *) result + alignment - adj;
+	UNLOCK;
+    }
+
+    return result;
+}
+#endif
+