libubacktrace: generic implementation based dwarf

Use the initial implementation for SH4 based on dwarf for all archs.
Indeed there are not obvious reason for which it should not work in general.

Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

1 files changed, 70 insertions, 5 deletions

diff --git a/libubacktrace/backtrace.c b/libubacktrace/backtrace.c
index 872180028..18b91b1bb 100644
--- a/libubacktrace/backtrace.c
+++ b/libubacktrace/backtrace.c
@@ -4,16 +4,81 @@
  * User application that wants to use backtrace needs to be
  * compiled with -fexceptions option and -rdynamic to get full
  * symbols printed.
-
- * Copyright (C) 2010 STMicroelectronics Ltd
+ *
+ * Copyright (C) 2009, 2010 STMicroelectronics Ltd.
+ *
+ * Author(s): Giuseppe Cavallaro <peppe.cavallaro@st.com>
+ * - Initial implementation for glibc
+ *
  * Author(s): Carmelo Amoroso <carmelo.amoroso@st.com>
+ * - Reworked for uClibc
+ *   - use dlsym/dlopen from libdl
+ *   - rewrite initialisation to not use libc_once
+ *   - make it available in static link too
  *
  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
  *
  */
-#error "Arch specific implementation must be provided to properly work"
-int backtrace (void **array, int size)
+
+#include <execinfo.h>
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <unwind.h>
+#include <assert.h>
+#include <stdio.h>
+
+struct trace_arg
 {
-	return -1;
+  void **array;
+  int cnt, size;
+};
+
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+
+static void backtrace_init (void)
+{
+	void *handle = dlopen ("libgcc_s.so.1", RTLD_LAZY);
+
+	if (handle == NULL
+		|| ((unwind_backtrace = dlsym (handle, "_Unwind_Backtrace")) == NULL)
+		|| ((unwind_getip = dlsym (handle, "_Unwind_GetIP")) == NULL)) {
+		printf("libgcc_s.so.1 must be installed for backtrace to work\n");
+		abort();
+	}
 }
 
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+	struct trace_arg *arg = a;
+
+	assert (unwind_getip != NULL);
+
+	/* We are first called with address in the __backtrace function. Skip it. */
+	if (arg->cnt != -1)
+		arg->array[arg->cnt] = (void *) unwind_getip (ctx);
+	if (++arg->cnt == arg->size)
+		return _URC_END_OF_STACK;
+	return _URC_NO_REASON;
+}
+
+/*
+ * Perform stack unwinding by using the _Unwind_Backtrace.
+ *
+ * User application that wants to use backtrace needs to be
+ * compiled with -fexceptions option and -rdynamic to get full
+ * symbols printed.
+ */
+int backtrace (void **array, int size)
+{
+	struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
+
+	if (unwind_backtrace == NULL)
+		backtrace_init();
+
+	if (size >= 1)
+		unwind_backtrace (backtrace_helper, &arg);
+
+	return arg.cnt != -1 ? arg.cnt : 0;
+}