add libpseudotalloc as super-simplistic talloc replacement

In tightly embedded builds (--enable-embedded), we want the ability to
replace talloc with a very simple heap allocator to avoid the complexity
of talloc without modifying all our code that assumes talloc.

This will break the hierarchical notion of the allocator, but
libosmo{core,gsm,coding,codec} don't rely on that anyway.

Change-Id: Ie341034076f242a813f081919dd09d845775ad35

3 files changed, 117 insertions, 0 deletions

diff --git a/src/pseudotalloc/Makefile.am b/src/pseudotalloc/Makefile.am
new file mode 100644
index 00000000..3c78bba8
--- /dev/null
+++ b/src/pseudotalloc/Makefile.am
@@ -0,0 +1,12 @@
+AM_CFLAGS = -Wall -I. $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)/include
+
+if ENABLE_PSEUDOTALLOC
+
+lib_LTLIBRARIES = libpseudotalloc.la
+
+libpseudotalloc_la_SOURCES = pseudotalloc.c
+libpseudotalloc_la_LDFLAGS = -no-undefined
+
+nobase_include_HEADERS = talloc.h
+
+endif
diff --git a/src/pseudotalloc/pseudotalloc.c b/src/pseudotalloc/pseudotalloc.c
new file mode 100644
index 00000000..fe7f1edc
--- /dev/null
+++ b/src/pseudotalloc/pseudotalloc.c
@@ -0,0 +1,63 @@
+/* overly simplistic talloc replacement for deeply embedded
+ * microcontrollers.  Obviously this has none of the properties of real
+ * talloc, it is particualrly not hierarchical at all */
+
+
+#include "talloc.h"
+#include <string.h>
+
+void *_talloc_zero(const void *ctx, size_t size, const char *name)
+{
+	void *p = pseudotalloc_malloc(size);
+	if (!p)
+		return NULL;
+	memset(p, 0, size);
+	return p;
+}
+
+int _talloc_free(void *ptr, const char *location)
+{
+	pseudotalloc_free(ptr);
+	return 0;
+}
+
+void *talloc_named_const(const void *context, size_t size, const char *name)
+{
+	return pseudotalloc_malloc(size);
+}
+
+void talloc_set_name_const(const void *ptr, const char *name)
+{
+}
+
+char *talloc_strdup(const void *context, const char *p)
+{
+	char *ptr;
+	size_t len;
+
+	if (!p)
+		return NULL;
+	len = strlen(p);
+
+	ptr = talloc_size(context, len+1);
+	if (!ptr)
+		return NULL;
+	memcpy(ptr, p, len+1);
+
+	return ptr;
+}
+
+void *talloc_pool(const void *context, size_t size)
+{
+	return (void *) context;
+}
+
+void *_talloc_array(const void *ctx, size_t el_size, unsigned count, const char *name)
+{
+	return talloc_size(ctx, el_size * count);
+}
+
+void *_talloc_zero_array(const void *ctx, size_t el_size, unsigned count, const char *name)
+{
+	return talloc_zero_size(ctx, el_size * count);
+}
diff --git a/src/pseudotalloc/talloc.h b/src/pseudotalloc/talloc.h
new file mode 100644
index 00000000..c7127deb
--- /dev/null
+++ b/src/pseudotalloc/talloc.h
@@ -0,0 +1,42 @@
+#pragma once
+
+/* overly simplistic talloc replacement for deeply embedded
+ * microcontrollers.  Obviously this has none of the properties of real
+ * talloc, it is particualrly not hierarchical at all */
+
+#include <stdlib.h>
+#include <stdarg.h>
+
+/* those two functions have to be provided by the user/environment */
+extern void *pseudotalloc_malloc(size_t size);
+extern void  pseudotalloc_free(void *ptr);
+
+typedef void TALLOC_CTX;
+
+#define __TALLOC_STRING_LINE1__(s)    #s
+#define __TALLOC_STRING_LINE2__(s)   __TALLOC_STRING_LINE1__(s)
+#define __TALLOC_STRING_LINE3__  __TALLOC_STRING_LINE2__(__LINE__)
+#define __location__ __FILE__ ":" __TALLOC_STRING_LINE3__
+
+#define talloc_zero(ctx, type) (type *)_talloc_zero(ctx, sizeof(type), #type)
+#define talloc_zero_size(ctx, size) _talloc_zero(ctx, size, __location__)
+void *_talloc_zero(const void *ctx, size_t size, const char *name);
+
+#define talloc_free(ctx) _talloc_free(ctx, __location__)
+int _talloc_free(void *ptr, const char *location);
+
+/* Unsupported! */
+#define talloc(ctx, type) (type *)talloc_named_const(ctx, sizeof(type), #type)
+#define talloc_size(ctx, size) talloc_named_const(ctx, size, __location__)
+void *talloc_named_const(const void *context, size_t size, const char *name);
+void talloc_set_name_const(const void *ptr, const char *name);
+char *talloc_strdup(const void *t, const char *p);
+void *talloc_pool(const void *context, size_t size);
+#define talloc_array(ctx, type, count) (type *)_talloc_array(ctx, sizeof(type), count, #type)
+void *_talloc_array(const void *ctx, size_t el_size, unsigned count, const char *name);
+#define talloc_zero_array(ctx, type, count) (type *)_talloc_zero_array(ctx, sizeof(type), count, #type)
+void *_talloc_zero_array(const void *ctx,
+			 size_t el_size,
+			 unsigned count,
+			 const char *name);
+