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- /*
- * Perform stack unwinding by using the _Unwind_Backtrace.
- *
- * User application that wants to use backtrace needs to be
- * compiled with -fasynchronous-unwind-tables option and -rdynamic to get full
- * symbols printed.
- *
- * 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.
- *
- */
- #include <libgcc_s.h>
- #include <execinfo.h>
- #include <dlfcn.h>
- #include <stdlib.h>
- #include <unwind.h>
- #include <assert.h>
- #include <stdio.h>
- struct trace_arg
- {
- void **array;
- int cnt, size;
- };
- #ifdef SHARED
- 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, RTLD_LAZY);
- if (handle == NULL
- || ((unwind_backtrace = dlsym (handle, "_Unwind_Backtrace")) == NULL)
- || ((unwind_getip = dlsym (handle, "_Unwind_GetIP")) == NULL)) {
- printf(LIBGCC_S_SO " must be installed for backtrace to work\n");
- abort();
- }
- }
- #else
- # define unwind_backtrace _Unwind_Backtrace
- # define unwind_getip _Unwind_GetIP
- #endif
- 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.
- *
- */
- int backtrace (void **array, int size)
- {
- struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
- #ifdef SHARED
- if (unwind_backtrace == NULL)
- backtrace_init();
- #endif
- if (size >= 1)
- unwind_backtrace (backtrace_helper, &arg);
- return arg.cnt != -1 ? arg.cnt : 0;
- }
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