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-rw-r--r--debug/backtrace.c158
1 files changed, 101 insertions, 57 deletions
diff --git a/debug/backtrace.c b/debug/backtrace.c
index c01b9585c7..d423cc053a 100644
--- a/debug/backtrace.c
+++ b/debug/backtrace.c
@@ -1,7 +1,7 @@
-/* Return backtrace of current program state. Generic version.
- Copyright (C) 1998-2016 Free Software Foundation, Inc.
+/* Return backtrace of current program state.
+ Copyright (C) 2003-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
- Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
+ Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
@@ -17,74 +17,118 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#include <libc-lock.h>
+#include <dlfcn.h>
#include <execinfo.h>
-#include <signal.h>
-#include <frame.h>
-#include <sigcontextinfo.h>
-#include <ldsodefs.h>
-
-/* This implementation assumes a stack layout that matches the defaults
- used by gcc's `__builtin_frame_address' and `__builtin_return_address'
- (FP is the frame pointer register):
-
- +-----------------+ +-----------------+
- FP -> | previous FP --------> | previous FP ------>...
- | | | |
- | return address | | return address |
- +-----------------+ +-----------------+
-
- */
-
-/* Get some notion of the current stack. Need not be exactly the top
- of the stack, just something somewhere in the current frame. */
-#ifndef CURRENT_STACK_FRAME
-# define CURRENT_STACK_FRAME ({ char __csf; &__csf; })
-#endif
+#include <gnu/lib-names.h>
+#include <stdlib.h>
+#include <unwind.h>
-/* By default we assume that the stack grows downward. */
-#ifndef INNER_THAN
-# define INNER_THAN <
-#endif
+struct trace_arg
+{
+ void **array;
+ _Unwind_Word cfa;
+ int cnt;
+ int size;
+};
+
+#ifdef SHARED
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+static _Unwind_Word (*unwind_getcfa) (struct _Unwind_Context *);
+static void *libgcc_handle;
+
+
+/* Dummy version in case libgcc_s does not contain the real code. */
+static _Unwind_Word
+dummy_getcfa (struct _Unwind_Context *ctx __attribute__ ((unused)))
+{
+ return 0;
+}
-/* By default assume the `next' pointer in struct layout points to the
- next struct layout. */
-#ifndef ADVANCE_STACK_FRAME
-# define ADVANCE_STACK_FRAME(next) ((struct layout *) (next))
-#endif
-/* By default, the frame pointer is just what we get from gcc. */
-#ifndef FIRST_FRAME_POINTER
-# define FIRST_FRAME_POINTER __builtin_frame_address (0)
+static void
+init (void)
+{
+ libgcc_handle = __libc_dlopen (LIBGCC_S_SO);
+
+ if (libgcc_handle == NULL)
+ return;
+
+ unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
+ unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
+ if (unwind_getip == NULL)
+ unwind_backtrace = NULL;
+ unwind_getcfa = (__libc_dlsym (libgcc_handle, "_Unwind_GetCFA")
+ ?: dummy_getcfa);
+}
+#else
+# define unwind_backtrace _Unwind_Backtrace
+# define unwind_getip _Unwind_GetIP
+# define unwind_getcfa _Unwind_GetCFA
#endif
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+ struct trace_arg *arg = a;
+
+ /* We are first called with address in the __backtrace function.
+ Skip it. */
+ if (arg->cnt != -1)
+ {
+ arg->array[arg->cnt] = (void *) unwind_getip (ctx);
+
+ /* Check whether we make any progress. */
+ _Unwind_Word cfa = unwind_getcfa (ctx);
+
+ if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]
+ && cfa == arg->cfa)
+ return _URC_END_OF_STACK;
+ arg->cfa = cfa;
+ }
+ if (++arg->cnt == arg->size)
+ return _URC_END_OF_STACK;
+ return _URC_NO_REASON;
+}
+
int
__backtrace (void **array, int size)
{
- struct layout *current;
- void *top_frame;
- void *top_stack;
- int cnt = 0;
+ struct trace_arg arg = { .array = array, .cfa = 0, .size = size, .cnt = -1 };
- top_frame = FIRST_FRAME_POINTER;
- top_stack = CURRENT_STACK_FRAME;
+ if (size <= 0)
+ return 0;
- /* We skip the call to this function, it makes no sense to record it. */
- current = ((struct layout *) top_frame);
- while (cnt < size)
- {
- if ((void *) current INNER_THAN top_stack
- || !((void *) current INNER_THAN __libc_stack_end))
- /* This means the address is out of range. Note that for the
- toplevel we see a frame pointer with value NULL which clearly is
- out of range. */
- break;
+#ifdef SHARED
+ __libc_once_define (static, once);
- array[cnt++] = current->return_address;
+ __libc_once (once, init);
+ if (unwind_backtrace == NULL)
+ return 0;
+#endif
- current = ADVANCE_STACK_FRAME (current->next);
- }
+ unwind_backtrace (backtrace_helper, &arg);
- return cnt;
+ /* _Unwind_Backtrace seems to put NULL address above
+ _start. Fix it up here. */
+ if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
+ --arg.cnt;
+ return arg.cnt != -1 ? arg.cnt : 0;
}
weak_alias (__backtrace, backtrace)
libc_hidden_def (__backtrace)
+
+
+#ifdef SHARED
+/* Free all resources if necessary. */
+libc_freeres_fn (free_mem)
+{
+ unwind_backtrace = NULL;
+ if (libgcc_handle != NULL)
+ {
+ __libc_dlclose (libgcc_handle);
+ libgcc_handle = NULL;
+ }
+}
+#endif