Inital import

[l4.git] / l4 / pkg / l4util / lib / src / ARCH-x86 / backtrace.c

diff --git a/l4/pkg/l4util/lib/src/ARCH-x86/backtrace.c b/l4/pkg/l4util/lib/src/ARCH-x86/backtrace.c
new file mode 100644 (file)
index 0000000..095c5ab
--- /dev/null
+++ b/l4/pkg/l4util/lib/src/ARCH-x86/backtrace.c
@@ -0,0 +1,117 @@
+/*
+ * (c) 2008-2009 Technische Universität Dresden
+ * This file is part of TUD:OS and distributed under the terms of the
+ * GNU Lesser General Public License 2.1.
+ * Please see the COPYING-LGPL-2.1 file for details.
+ */
+#include <l4/util/backtrace.h>
+
+#include <unwind.h>
+#include <stdlib.h>
+
+#if defined NOT_FOR_L4 && defined __PIC__
+
+#include <dlfcn.h>
+
+static _Unwind_Reason_Code (*uw_bt) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*uw_getpc) (struct _Unwind_Context *);
+static _Unwind_Ptr (*uw_getcfa) (struct _Unwind_Context *);
+static _Unwind_Ptr (*uw_getgr) (struct _Unwind_Context *, int);
+
+static void
+init (void)
+{
+  void *handle = dlopen ("libgcc_s.so.1", 0);
+
+  if (handle == NULL)
+    return;
+
+  uw_bt     = dlsym (handle, "_Unwind_Backtrace");
+  uw_getpc  = dlsym (handle, "_Unwind_GetIP");
+  uw_getcfa = dlsym (handle, "_Unwind_GetCFA");
+  uw_getgr  = dlsym (handle, "_Unwind_GetGR");
+  if (uw_getpc == NULL || uw_getgr == NULL || uw_getcfa == NULL)
+    uw_bt = NULL;
+}
+#else
+
+#define uw_getgr _Unwind_GetGR
+#define uw_getpc _Unwind_GetIP
+#define uw_bt _Unwind_Backtrace
+#define uw_getcfa _Unwind_GetCFA
+
+#endif
+
+struct Bt_arg
+{
+  void **pc_array;
+  int  cnt, max;
+  void *last_frame;
+  void *last_sp;
+};
+
+
+static _Unwind_Reason_Code
+__bt_helper(struct _Unwind_Context *ctx, void *a)
+{
+  struct Bt_arg *arg = a;
+
+  /* Skip first function, it is l4util_backtrace ... */
+  if (arg->cnt != -1)
+    arg->pc_array[arg->cnt] = (void *)uw_getpc (ctx);
+  if (++arg->cnt == arg->max)
+    return _URC_END_OF_STACK;
+
+  /* IA32: %ebp is DWARF2 register 5 */
+  arg->last_sp    = (void *)uw_getcfa (ctx);
+  arg->last_frame = (void *)uw_getgr (ctx, 5);
+  return _URC_NO_REASON;
+}
+struct Frame
+{
+  struct Frame *fp;
+  void *ret;
+};
+
+
+int
+l4util_backtrace(void **pc_array, int max)
+{
+  struct Bt_arg arg = { .pc_array = pc_array, .max = max, .cnt = -1 };
+
+#if defined NOT_FOR_L4 && defined __PIC__
+  static int initialized = 0;
+  if (!initialized)
+    {
+      initialized = 1;
+      init();
+    }
+
+  if (uw_bt == NULL)
+    return 0;
+#endif
+
+  if (max >= 1)
+    uw_bt (__bt_helper, &arg);
+
+  if (arg.cnt > 1 && arg.pc_array[arg.cnt - 1] == (void*)0)
+    --arg.cnt;
+  else if (arg.cnt < max)
+    {
+      struct Frame *fp = (struct Frame *)arg.last_frame;
+
+      while (arg.cnt < max)
+        {
+          /* Check for out of range.  */
+          if ((void *)fp < arg.last_sp
+              /* || (void *) ebp > __libc_stack_end*/
+              || ((long)fp & 3))
+            break;
+
+          pc_array[arg.cnt++] = fp->ret;
+          fp = fp->fp;
+        }
+    }
+  return arg.cnt != -1 ? arg.cnt : 0;
+}
+