diff options
Diffstat (limited to 'REORG.TODO/sysdeps/i386/backtrace.c')
| -rw-r--r-- | REORG.TODO/sysdeps/i386/backtrace.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/i386/backtrace.c b/REORG.TODO/sysdeps/i386/backtrace.c new file mode 100644 index 0000000000..ee8238d0ce --- /dev/null +++ b/REORG.TODO/sysdeps/i386/backtrace.c @@ -0,0 +1,163 @@ +/* Return backtrace of current program state. + Copyright (C) 1998-2017 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 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + 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 <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 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 *ebp; + void *ret; +}; + + +int +__backtrace (void **array, int 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) + { + struct layout *ebp = (struct layout *) arg.lastebp; + + while (arg.cnt < size) + { + /* Check for out of range. */ + if ((void *) ebp < arg.lastesp || (void *) ebp > __libc_stack_end + || ((long) ebp & 3)) + break; + + array[arg.cnt++] = ebp->ret; + ebp = ebp->ebp; + } + } + 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 |