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      1 /* libunwind - a platform-independent unwind library
      2    Copyright (C) 2014 The Android Open Source Project
      3 
      4 This file is part of libunwind.
      5 
      6 Permission is hereby granted, free of charge, to any person obtaining
      7 a copy of this software and associated documentation files (the
      8 "Software"), to deal in the Software without restriction, including
      9 without limitation the rights to use, copy, modify, merge, publish,
     10 distribute, sublicense, and/or sell copies of the Software, and to
     11 permit persons to whom the Software is furnished to do so, subject to
     12 the following conditions:
     13 
     14 The above copyright notice and this permission notice shall be
     15 included in all copies or substantial portions of the Software.
     16 
     17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     18 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     19 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     20 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     21 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     22 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     23 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
     24 
     25 #define UNW_LOCAL_ONLY
     26 #include <libunwind.h>
     27 #include "libunwind_i.h"
     28 
     29 /* Globals to hold the map data for local unwinds. */
     30 HIDDEN struct map_info *local_map_list = NULL;
     31 HIDDEN int local_map_list_refs = 0;
     32 HIDDEN lock_rdwr_var (local_rdwr_lock);
     33 
     34 PROTECTED void
     35 unw_map_local_cursor_get (unw_map_cursor_t *map_cursor)
     36 {
     37   intrmask_t saved_mask;
     38 
     39   /* This function can be called before any other unwind code, so make sure
     40      the lock has been initialized.  */
     41   map_local_init ();
     42 
     43   lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
     44   map_cursor->map_list = local_map_list;
     45   map_cursor->cur_map = local_map_list;
     46   lock_rdwr_release (&local_rdwr_lock, saved_mask);
     47 }
     48 
     49 PROTECTED int
     50 unw_map_local_cursor_valid (unw_map_cursor_t *map_cursor)
     51 {
     52   if (map_cursor->map_list == local_map_list)
     53     return 0;
     54   return -1;
     55 }
     56 
     57 PROTECTED int
     58 unw_map_local_create (void)
     59 {
     60   intrmask_t saved_mask;
     61   int ret_value = 0;
     62 
     63   /* This function can be called before any other unwind code, so make sure
     64      the lock has been initialized.  */
     65   map_local_init ();
     66 
     67   lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
     68   if (local_map_list_refs == 0)
     69     {
     70       local_map_list = map_create_list (getpid());
     71       if (local_map_list != NULL)
     72         local_map_list_refs = 1;
     73       else
     74         ret_value = -1;
     75     }
     76   else
     77     local_map_list_refs++;
     78   lock_rdwr_release (&local_rdwr_lock, saved_mask);
     79   return ret_value;
     80 }
     81 
     82 PROTECTED void
     83 unw_map_local_destroy (void)
     84 {
     85   intrmask_t saved_mask;
     86 
     87   /* This function can be called before any other unwind code, so make sure
     88      the lock has been initialized.  */
     89   map_local_init ();
     90 
     91   lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
     92   if (local_map_list != NULL && --local_map_list_refs == 0)
     93     {
     94       map_destroy_list (local_map_list);
     95       local_map_list = NULL;
     96     }
     97   lock_rdwr_release (&local_rdwr_lock, saved_mask);
     98 }
     99 
    100 PROTECTED int
    101 unw_map_local_cursor_get_next (unw_map_cursor_t *map_cursor, unw_map_t *unw_map)
    102 {
    103   struct map_info *map_info = map_cursor->cur_map;
    104   intrmask_t saved_mask;
    105   int ret = 1;
    106 
    107   if (map_info == NULL)
    108     return 0;
    109 
    110   /* This function can be called before any other unwind code, so make sure
    111      the lock has been initialized.  */
    112   map_local_init ();
    113 
    114   lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
    115   if (map_cursor->map_list != local_map_list)
    116     {
    117       map_cursor->map_list = local_map_list;
    118       ret = -UNW_EINVAL;
    119     }
    120   else
    121     {
    122       unw_map->start = map_info->start;
    123       unw_map->end = map_info->end;
    124       unw_map->flags = map_info->flags;
    125       if (map_info->path)
    126         unw_map->path = strdup (map_info->path);
    127       else
    128         unw_map->path = NULL;
    129 
    130       map_cursor->cur_map = map_info->next;
    131     }
    132   lock_rdwr_release (&local_rdwr_lock, saved_mask);
    133 
    134   return ret;
    135 }
    136