1 files changed, 61 insertions, 0 deletions
diff --git a/save_backtrace.c b/save_backtrace.c
new file mode 100644
index 0000000..e366abf
--- /dev/null
+++ b/save_backtrace.c
@@ -0,0 +1,61 @@
+/* See LICENSE file for copyright and license details. */
+#include "internal.h"
+
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+
+
+struct partial {
+	uintptr_t rips[8];
+	struct partial *next;
+};
+
+
+int
+liberror_save_backtrace(struct liberror_error *error)
+{
+	struct liberror_backtrace *backtrace = NULL;
+	unw_word_t rip;
+	unw_cursor_t cursor;
+	unw_context_t context;
+	size_t i = 0;
+	struct partial *current, head;
+	int saved_errno = errno;
+	int ret = -1;
+
+	if (unw_getcontext(&context))
+		goto out;
+	if (unw_init_local(&cursor, &context))
+		goto out;
+
+	current = &head;
+
+	for (; unw_step(&cursor) > 0; i++) {
+		if (!(i & 7))
+			current = current->next = alloca(sizeof(*current));
+		if (unw_get_reg(&cursor, UNW_REG_IP, &rip))
+			goto out;
+		current->rips[i & 7] = (uintptr_t)rip;
+	}
+
+	backtrace = malloc(offsetof(struct liberror_backtrace, rips) + i * sizeof(*backtrace->rips));
+	if (!backtrace)
+		goto out;
+	backtrace->refcount = 1;
+
+	backtrace->n = i;
+	current = &head;
+	for (i = 0; i < backtrace->n; i++) {
+		if (!(i & 7))
+			current = current->next;
+		backtrace->rips[i] = current->rips[i & 7];
+	}
+
+	ret = 0;
+out:
+	if (error->backtrace && !--error->backtrace->refcount)
+		free(error->backtrace);
+	error->backtrace = backtrace;
+	errno = saved_errno;
+	return ret;
+}