/* Return backtrace of current program state.
- Copyright (C) 1998 Free Software Foundation, Inc.
+ Copyright (C) 1998-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Library General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Library General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If not,
- write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+#include <libc-lock.h>
+#include <dlfcn.h>
#include <execinfo.h>
+#include <stdlib.h>
+#include <unwind.h>
+struct trace_arg
+{
+ void **array;
+ int cnt, size;
+ void *lastebp, *lastesp;
+};
+
+#ifdef SHARED
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+static _Unwind_Ptr (*unwind_getcfa) (struct _Unwind_Context *);
+static _Unwind_Ptr (*unwind_getgr) (struct _Unwind_Context *, int);
+static void *libgcc_handle;
+
+static void
+init (void)
+{
+ libgcc_handle = __libc_dlopen ("libgcc_s.so.1");
+
+ if (libgcc_handle == NULL)
+ return;
+
+ unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
+ unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
+ unwind_getcfa = __libc_dlsym (libgcc_handle, "_Unwind_GetCFA");
+ unwind_getgr = __libc_dlsym (libgcc_handle, "_Unwind_GetGR");
+ if (unwind_getip == NULL || unwind_getgr == NULL || unwind_getcfa == NULL)
+ {
+ unwind_backtrace = NULL;
+ __libc_dlclose (libgcc_handle);
+ libgcc_handle = NULL;
+ }
+}
+#else
+# define unwind_backtrace _Unwind_Backtrace
+# define unwind_getip _Unwind_GetIP
+# define unwind_getcfa _Unwind_GetCFA
+# define unwind_getgr _Unwind_GetGR
+#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);
+ if (++arg->cnt == arg->size)
+ return _URC_END_OF_STACK;
+
+ /* %ebp is DWARF2 register 5 on IA-32. */
+ arg->lastebp = (void *) unwind_getgr (ctx, 5);
+ arg->lastesp = (void *) unwind_getcfa (ctx);
+ return _URC_NO_REASON;
+}
+
+
+/* This is a global variable set at program start time. It marks the
+ highest used stack address. */
+extern void *__libc_stack_end;
-/* This is the stack alyout we see with every stack frame.
+
+/* This is the stack layout we see with every stack frame
+ if not compiled without frame pointer.
+-----------------+ +-----------------+
%ebp -> | %ebp last frame--------> | %ebp last frame--->...
| | | |
| return address | | return address |
+-----------------+ +-----------------+
-*/
+
+ First try as far to get as far as possible using
+ _Unwind_Backtrace which handles -fomit-frame-pointer
+ as well, but requires .eh_frame info. Then fall back to
+ walking the stack manually. */
+
struct layout
{
- struct layout *next;
- void *return_address;
+ struct layout *ebp;
+ void *ret;
};
+
int
-__backtrace (array, size)
- void **array;
- int size;
+__backtrace (void **array, int size)
{
- /* We assume that all the code is generated with frame pointers set. */
- register void *ebp __asm__ ("ebp");
- struct layout *current;
- int cnt = 0;
-
- /* We skip the call to this function, it makes no sense to record it. */
- current = (struct layout *) ebp;
- while (cnt < size)
+ struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
+
+ if (size <= 0)
+ return 0;
+
+#ifdef SHARED
+ __libc_once_define (static, once);
+
+ __libc_once (once, init);
+ if (unwind_backtrace == NULL)
+ return 0;
+#endif
+
+ unwind_backtrace (backtrace_helper, &arg);
+
+ if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
+ --arg.cnt;
+ else if (arg.cnt < size)
{
- if (current == NULL)
- /* This means the toplevel is reached. */
- break;
+ struct layout *ebp = (struct layout *) arg.lastebp;
- array[cnt++] = current->return_address;
+ while (arg.cnt < size)
+ {
+ /* Check for out of range. */
+ if ((void *) ebp < arg.lastesp || (void *) ebp > __libc_stack_end
+ || ((long) ebp & 3))
+ break;
- current = current->next;
+ array[arg.cnt++] = ebp->ret;
+ ebp = ebp->ebp;
+ }
}
-
- return 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
projects / thirdparty / glibc.git / blobdiff