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82 lines
2 KiB
C
82 lines
2 KiB
C
/* libunwind - a platform-independent unwind library
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Copyright (C) 2001-2002 Hewlett-Packard Co
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Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
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This file is part of libunwind.
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libunwind is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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libunwind is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details. */
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/* This shows how to use the unwind interface to modify any ancestor
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frame while still returning to the parent frame. */
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#include <signal.h>
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#include <stdio.h>
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#include <unwind.h>
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#define panic(args...) \
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{ fprintf (stderr, args); exit (-1); }
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static void
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sighandler (int signal)
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{
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unw_cursor_t cursor, cursor2;
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unw_word_t rp;
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unw_context_t uc;
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printf ("caught signal %d\n", signal);
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unw_getcontext(&uc);
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if (unw_init (&cursor, &uc) < 0)
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panic ("unw_init() failed!\n");
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/* get cursor for caller of sighandler: */
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if (unw_step (&cursor) < 0)
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panic ("unw_step() failed!\n");
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cursor2 = cursor;
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while (!unw_is_signal_frame (&cursor2))
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if (unw_step (&cursor2) < 0)
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panic ("failed to find signal frame!\n");
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if (unw_get_reg (&cursor2, UNW_REG_RP, &rp) < 0)
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panic ("failed to get IP!\n");
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/* skip faulting instruction (doesn't handle MLX template) */
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++rp;
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if (rp & 0x3 == 0x3)
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rp += 13;
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if (unw_set_reg (&cursor2, UNW_REG_RP, rp) < 0)
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panic ("failed to set IP!\n");
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unw_resume (&cursor); /* update context & return to caller of sighandler() */
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panic ("unexpected return from unw_resume()!\n");
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}
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static void
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doit (char *p)
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{
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int ch;
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ch = *p; /* trigger SIGSEGV */
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printf ("doit: finishing execution!\n");
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}
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int
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main (int argc, char **argv)
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{
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signal (SIGSEGV, sighandler);
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doit (0);
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}
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