simple leak tracer, using libexecinfo

Makefile

@@ -0,0 +1,28 @@
+#	$OpenBSD$
+
+LIB=	leakmalloc
+SRCS=	leakmalloc.c
+HDRS=	leakmalloc.h
+#MAN=	leakmalloc.3
+NOMAN=1
+NOPIC=1
+NOPROFILE=1
+
+CDIAGFLAGS=	-Wall
+CDIAGFLAGS+=	-Werror
+CDIAGFLAGS+=	-Wstrict-prototypes
+CDIAGFLAGS+=	-Wmissing-prototypes
+CDIAGFLAGS+=	-Wmissing-declarations
+CDIAGFLAGS+=	-Wshadow
+CDIAGFLAGS+=	-Wpointer-arith
+CDIAGFLAGS+=	-Wcast-qual
+CDIAGFLAGS+=	-Wsign-compare
+CDIAGFLAGS+=	-Wcast-align
+CDIAGFLAGS+=	-Wbad-function-cast
+
+CPPFLAGS+= -I/usr/local/include
+DEBUG=-ggdb3
+COPTS=-O0
+INSTALL_STRIP=
+
+.include <bsd.lib.mk>

leakmalloc.c

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2012 Damien Miller <djm@mindrot.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/tree.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <err.h>
+
+#include <execinfo.h>
+
+#define LEAKMALLOC_NO_REDIRECT
+#include "leakmalloc.h"
+
+static int initialised;
+
+struct alloc {
+	RB_ENTRY(alloc) entry;
+	void *addr;
+	size_t len;
+	void *bt[BT_MAX_DEPTH];
+	int depth;
+};
+
+static int
+alloc_cmp(struct alloc *a, struct alloc *b)
+{
+	return (a->addr == b->addr) ? 0 : (a->addr < b->addr ? -1 : 1);
+}
+
+RB_HEAD(alloc_tree, alloc);
+RB_GENERATE_STATIC(alloc_tree, alloc, entry, alloc_cmp);
+static struct alloc_tree alloc_tree = RB_INITIALIZER(&alloc_tree);
+
+/* Called atexit to dump unfreed leak objects */
+static void
+dump_leaks(void)
+{
+	struct alloc *alloc;
+	int i;
+
+	RB_FOREACH(alloc, alloc_tree, &alloc_tree) {
+		printf("LEAK %p %zu TRACE", alloc->addr, alloc->len);
+		for (i = 0; i < alloc->depth; i++)
+			printf(" %p", alloc->bt[i]);
+		printf("\n");
+	}
+}
+
+void __record_leak(void *addr, size_t len, void *oaddr);
+void
+__record_leak(void *addr, size_t len, void *oaddr)
+{
+	struct alloc oalloc, *alloc;
+
+	if (!initialised) {
+		atexit(dump_leaks);
+		initialised = 1;
+	}
+
+	if (addr == NULL || addr == oaddr)
+		return;
+	if (oaddr == NULL) {
+		/*
+		 * malloc/calloc: allocate a leak object and fill in the
+		 * trace.
+		 */
+		if ((alloc = calloc(1, sizeof(*alloc))) == NULL)
+			errx(1, "%s: calloc failed", __func__);	
+		alloc->addr = addr;
+		alloc->len = len;
+		if ((alloc->depth = backtrace(alloc->bt, BT_MAX_DEPTH)) == -1)
+			errx(1, "%s: backtrace failed", __func__);
+		if (RB_INSERT(alloc_tree, &alloc_tree, alloc) != NULL)
+			errx(1, "%s: alloc for %p already exists",
+			    __func__, addr);
+	} else {
+		oalloc.addr = oaddr;
+		alloc = RB_FIND(alloc_tree, &alloc_tree, &oalloc);
+		if (addr == NULL) {
+			/*
+			 * free: delete the tracked leak.
+			 */
+			if (alloc == NULL)
+				return; /* Ignore untracked memory */
+			RB_REMOVE(alloc_tree, &alloc_tree, alloc);
+			free(alloc);
+		} else {
+			/*
+			 * realloc: update the original address so we can 
+			 * trace it when it is freed.
+			 */
+			if (alloc == NULL)
+				errx(1, "%s: original addr missing", __func__);
+			alloc->addr = addr;
+			alloc->len = len;
+		}
+	}
+}
+
+char *
+leak_strdup(const char *s)
+{
+	char *ret = strdup(s);
+
+	__record_leak(ret, ret == NULL ? 0 : strlen(ret), NULL);
+	return ret;
+}
+
+void *
+leak_malloc(size_t len)
+{
+	void *ret = malloc(len);
+
+	__record_leak(ret, len, NULL);
+	return ret;
+}
+
+void *
+leak_calloc(size_t nmemb, size_t size)
+{
+	void *ret = calloc(nmemb, size);
+
+	__record_leak(ret, nmemb * size, NULL);
+	return ret;
+}
+
+void *
+leak_realloc(void *s, size_t len)
+{
+	void *ret = realloc(s, len);
+	
+	__record_leak(ret, len, s);
+	return ret;
+}
+
+void
+leak_free(void *s)
+{
+	free(s);
+	__record_leak(NULL, 0, s);
+}
+

leakmalloc.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2012 Damien Miller <djm@mindrot.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _LEAKMALLOC_H
+#define _LEAKMALLOC_H
+
+#include <sys/types.h>
+
+char *leak_strdup(const char *s);
+void *leak_malloc(size_t len);
+void *leak_calloc(size_t nmemb, size_t size);
+void *leak_realloc(void *s, size_t len);
+void leak_free(void *s);
+
+#ifndef LEAKMALLOC_NO_REDIRECT
+#define malloc	leak_malloc
+#define strdup	leak_strdup
+#define calloc	leak_calloc
+#define realloc	leak_realloc
+#define free	leak_free
+#endif /* LEAKMALLOC_NO_REDIRECT */
+
+#endif /* _LEAKMALLOC_H */
+