first public release of samba4 code

source/lib/talloc.c

@@ -0,0 +1,515 @@
+/* 
+   Samba Unix SMB/CIFS implementation.
+   Samba temporary memory allocation functions
+   Copyright (C) Andrew Tridgell 2000
+   Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU 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 General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/**
+   @defgroup talloc Simple memory allocator
+   @{
+   
+   This is a very simple temporary memory allocator. To use it do the following:
+
+   1) when you first want to allocate a pool of meomry use
+   talloc_init() and save the resulting context pointer somewhere
+
+   2) to allocate memory use talloc()
+
+   3) when _all_ of the memory allocated using this context is no longer needed
+   use talloc_destroy()
+
+   talloc does not zero the memory. It guarantees memory of a
+   TALLOC_ALIGN alignment
+
+   @sa talloc.h
+*/
+
+/**
+ * @todo We could allocate both the talloc_chunk structure, and the
+ * memory it contains all in one allocation, which might be a bit
+ * faster and perhaps use less memory overhead.
+ *
+ * That smells like a premature optimization, though.  -- mbp
+ **/
+
+/**
+ * If you want testing for memory corruption, link with dmalloc or use
+ * Insure++.  It doesn't seem useful to duplicate them here.
+ **/
+
+#include "includes.h"
+
+struct talloc_chunk {
+	struct talloc_chunk *next;
+	size_t size;
+	void *ptr;
+};
+
+
+struct talloc_ctx {
+	struct talloc_chunk *list;
+	off_t total_alloc_size;
+
+	/** The name recorded for this pool, if any.  Should describe
+	 * the purpose for which it was allocated.  The string is
+	 * allocated within the pool. **/
+	char *name;
+
+	/** Pointer to the next allocate talloc pool, so that we can
+	 * summarize all talloc memory usage. **/
+	struct talloc_ctx *next, *prev;
+};
+
+
+/**
+ * Start of linked list of all talloc pools.
+ *
+ * @todo We should turn the global list off when using Insure++,
+ * otherwise all the memory will be seen as still reachable.
+ **/
+static TALLOC_CTX *list_head;
+
+/**
+ * Add to the global list
+ **/
+static void talloc_enroll(TALLOC_CTX *t)
+{
+#if 0
+	/* disabled enrole/disenrole until we have __thread support */
+	MUTEX_LOCK_BY_ID(MUTEX_TALLOC);
+	DLIST_ADD(list_head, t);
+	MUTEX_UNLOCK_BY_ID(MUTEX_TALLOC);
+#endif
+}
+
+
+static void talloc_disenroll(TALLOC_CTX *t)
+{
+#if 0
+	/* disabled enrole/disenrole until we have __thread support */
+	MUTEX_LOCK_BY_ID(MUTEX_TALLOC);
+	DLIST_REMOVE(list_head, t);
+	MUTEX_UNLOCK_BY_ID(MUTEX_TALLOC);
+#endif
+}
+
+
+/** Create a new talloc context. **/
+static TALLOC_CTX *talloc_init_internal(void)
+{
+	TALLOC_CTX *t;
+
+	t = (TALLOC_CTX *)malloc(sizeof(TALLOC_CTX));
+	if (t) {
+		t->list = NULL;
+		t->total_alloc_size = 0;
+		t->name = NULL;
+		talloc_enroll(t);
+	}
+
+	return t;
+}
+
+
+
+/**
+ * Create a new talloc context, with a name specifying its purpose.
+ **/
+
+ TALLOC_CTX *talloc_init(char const *fmt, ...) 
+{
+	TALLOC_CTX *t;
+	va_list ap;
+
+	t = talloc_init_internal();
+	if (t && fmt) {
+		/*
+		 * t->name must not be talloced.
+		 * as destroying the pool would destroy it. JRA.
+		 */
+		t->name = NULL;
+		va_start(ap, fmt);
+		vasprintf(&t->name, fmt, ap);
+		va_end(ap);
+		if (!t->name) {
+			talloc_destroy(t);
+			t = NULL;
+		}
+	}
+	
+	return t;
+}
+
+
+/** Allocate a bit of memory from the specified pool **/
+void *talloc(TALLOC_CTX *t, size_t size)
+{
+	void *p;
+	struct talloc_chunk *tc;
+
+	if (!t || size == 0) return NULL;
+
+	p = malloc(size);
+	if (p) {
+		tc = malloc(sizeof(*tc));
+		if (tc) {
+			tc->ptr = p;
+			tc->size = size;
+			tc->next = t->list;
+			t->list = tc;
+			t->total_alloc_size += size;
+		}
+		else {
+			SAFE_FREE(p);
+		}
+	}
+	return p;
+}
+
+/** A talloc version of realloc */
+void *talloc_realloc(TALLOC_CTX *t, void *ptr, size_t size)
+{
+	struct talloc_chunk *tc;
+	void *new_ptr;
+
+	/* size zero is equivalent to free() */
+	if (!t || size == 0)
+		return NULL;
+
+	/* realloc(NULL) is equavalent to malloc() */
+	if (ptr == NULL)
+		return talloc(t, size);
+
+	for (tc=t->list; tc; tc=tc->next) {
+		if (tc->ptr == ptr) {
+			new_ptr = Realloc(ptr, size);
+			if (new_ptr) {
+				t->total_alloc_size += (size - tc->size);
+				tc->size = size;
+				tc->ptr = new_ptr;
+			}
+			return new_ptr;
+		}
+	}
+	return NULL;
+}
+
+/** Destroy all the memory allocated inside @p t, but not @p t
+ * itself. */
+void talloc_destroy_pool(TALLOC_CTX *t)
+{
+	struct talloc_chunk *c;
+	
+	if (!t)
+		return;
+
+	while (t->list) {
+		c = t->list->next;
+		SAFE_FREE(t->list->ptr);
+		SAFE_FREE(t->list);
+		t->list = c;
+	}
+
+	t->total_alloc_size = 0;
+}
+
+/** Destroy a whole pool including the context */
+void talloc_destroy(TALLOC_CTX *t)
+{
+	if (!t)
+		return;
+
+	talloc_destroy_pool(t);
+	talloc_disenroll(t);
+	SAFE_FREE(t->name);
+	SAFE_FREE(t);
+}
+
+/** Return the current total size of the pool. */
+size_t talloc_pool_size(TALLOC_CTX *t)
+{
+	return t->total_alloc_size;
+}
+
+const char *talloc_pool_name(TALLOC_CTX const *t)
+{
+	if (t) return t->name;
+
+	return NULL;
+}
+
+
+/** talloc and zero memory. */
+void *talloc_zero(TALLOC_CTX *t, size_t size)
+{
+	void *p = talloc(t, size);
+
+	if (p) {
+		memset(p, '\0', size);
+	}
+
+	return p;
+}
+
+
+/** memdup with a talloc. */
+void *talloc_memdup(TALLOC_CTX *t, const void *p, size_t size)
+{
+	void *newp = talloc(t,size);
+
+	if (newp) {
+		memcpy(newp, p, size);
+	}
+
+	return newp;
+}
+
+/** strdup with a talloc */
+char *talloc_strdup(TALLOC_CTX *t, const char *p)
+{
+	return talloc_memdup(t, p, strlen(p) + 1);
+}
+
+/** strndup with a talloc */
+char *talloc_strndup(TALLOC_CTX *t, const char *p, size_t n)
+{
+	size_t len = strnlen(p, n);
+	char *ret;
+
+	ret = talloc(t, len + 1);
+	if (!ret) { return NULL; }
+	memcpy(ret, p, len);
+	ret[len] = 0;
+	return ret;
+}
+
+/** strdup_w with a talloc */
+smb_ucs2_t *talloc_strdup_w(TALLOC_CTX *t, const smb_ucs2_t *p)
+{
+	if (p)
+		return talloc_memdup(t, p, (strlen_w(p) + 1) * sizeof(smb_ucs2_t));
+	return NULL;
+}
+
+/**
+ * Perform string formatting, and return a pointer to newly allocated
+ * memory holding the result, inside a memory pool.
+ **/
+ char *talloc_asprintf(TALLOC_CTX *t, const char *fmt, ...)
+{
+	va_list ap;
+	char *ret;
+
+	va_start(ap, fmt);
+	ret = talloc_vasprintf(t, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+
+ char *talloc_vasprintf(TALLOC_CTX *t, const char *fmt, va_list ap)
+{	
+	int len;
+	char *ret;
+	va_list ap2;
+	
+	VA_COPY(ap2, ap);
+
+	len = vsnprintf(NULL, 0, fmt, ap2);
+
+	ret = talloc(t, len+1);
+	if (ret) {
+		VA_COPY(ap2, ap);
+		vsnprintf(ret, len+1, fmt, ap2);
+	}
+
+	return ret;
+}
+
+
+/**
+ * Realloc @p s to append the formatted result of @p fmt and return @p
+ * s, which may have moved.  Good for gradually accumulating output
+ * into a string buffer.
+ **/
+ char *talloc_asprintf_append(TALLOC_CTX *t, char *s,
+			      const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	s = talloc_vasprintf_append(t, s, fmt, ap);
+	va_end(ap);
+	return s;
+}
+
+
+
+/**
+ * Realloc @p s to append the formatted result of @p fmt and @p ap,
+ * and return @p s, which may have moved.  Good for gradually
+ * accumulating output into a string buffer.
+ **/
+ char *talloc_vasprintf_append(TALLOC_CTX *t, char *s,
+			       const char *fmt, va_list ap)
+{	
+	int len, s_len;
+	va_list ap2;
+
+	VA_COPY(ap2, ap);
+
+	s_len = strlen(s);
+	len = vsnprintf(NULL, 0, fmt, ap2);
+
+	s = talloc_realloc(t, s, s_len + len+1);
+	if (!s) return NULL;
+
+	VA_COPY(ap2, ap);
+
+	vsnprintf(s+s_len, len+1, fmt, ap2);
+
+	return s;
+}
+
+
+/**
+ * Return a human-readable description of all talloc memory usage.
+ * The result is allocated from @p t.
+ **/
+char *talloc_describe_all(TALLOC_CTX *rt)
+{
+	int n_pools = 0, total_chunks = 0;
+	size_t total_bytes = 0;
+	TALLOC_CTX *it;
+	char *s;
+
+	if (!rt) return NULL;
+
+	s = talloc_asprintf(rt, "global talloc allocations in pid: %u\n",
+			    (unsigned) getpid());
+	s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
+				   "name", "chunks", "bytes");
+	s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
+				   "----------------------------------------",
+				   "--------",
+				   "--------");	
+	MUTEX_LOCK_BY_ID(MUTEX_TALLOC);
+	
+	for (it = list_head; it; it = it->next) {
+		size_t bytes;
+		int n_chunks;
+		fstring what;
+		
+		n_pools++;
+		
+		talloc_get_allocation(it, &bytes, &n_chunks);
+
+		if (it->name)
+			fstrcpy(what, it->name);
+		else
+			slprintf(what, sizeof(what), "@%p", it);
+		
+		s = talloc_asprintf_append(rt, s, "%-40s %8u %8u\n",
+					   what,
+					   (unsigned) n_chunks,
+					   (unsigned) bytes);
+		total_bytes += bytes;
+		total_chunks += n_chunks;
+	}
+
+	MUTEX_UNLOCK_BY_ID(MUTEX_TALLOC);
+
+	s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
+				   "----------------------------------------",
+				   "--------",
+				   "--------");	
+
+	s = talloc_asprintf_append(rt, s, "%-40s %8u %8u\n",
+				   "TOTAL",
+				   (unsigned) total_chunks, (unsigned) total_bytes);
+
+	return s;
+}
+
+
+
+/**
+ * Return an estimated memory usage for the specified pool.  This does
+ * not include memory used by the underlying malloc implementation.
+ **/
+void talloc_get_allocation(TALLOC_CTX *t,
+			   size_t *total_bytes,
+			   int *n_chunks)
+{
+	struct talloc_chunk *chunk;
+
+	if (t) {
+		*total_bytes = 0;
+		*n_chunks = 0;
+
+		for (chunk = t->list; chunk; chunk = chunk->next) {
+			n_chunks[0]++;
+			*total_bytes += chunk->size;
+		}
+	}
+}
+
+
+/* 
+   move a lump of memory from one talloc context to another
+   return the ptr on success, or NULL if it could not be found
+   in the old context or could not be transferred
+*/
+const void *talloc_steal(TALLOC_CTX *old_ctx, TALLOC_CTX *new_ctx, const void *ptr)
+{
+	struct talloc_chunk *tc, *tc2;
+
+	if (!ptr || !old_ctx->list) return NULL;
+
+	/* as a special case, see if its the first element in the
+	   list */
+	if (old_ctx->list->ptr == ptr) {
+		tc = old_ctx->list;
+		old_ctx->list = old_ctx->list->next;
+		tc->next = new_ctx->list;
+		new_ctx->list = tc;
+		old_ctx->total_alloc_size -= tc->size;
+		new_ctx->total_alloc_size += tc->size;
+		return ptr;
+	}
+
+	/* find it in the old context */
+	for (tc=old_ctx->list; tc->next; tc=tc->next) {
+		if (tc->next->ptr == ptr) break;
+	}
+
+	if (!tc->next) return NULL;
+
+	/* move it to the new context */
+	tc2 = tc->next;
+	tc->next = tc->next->next;
+	tc2->next = new_ctx->list;
+	new_ctx->list = tc2;
+	old_ctx->total_alloc_size -= tc2->size;
+	new_ctx->total_alloc_size += tc2->size;
+	
+	return ptr;
+}
+
+
+/** @} */