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1 /* libunwind - a platform-independent unwind library
2 
3 This file is part of libunwind.
4 
5 Permission is hereby granted, free of charge, to any person obtaining
6 a copy of this software and associated documentation files (the
7 "Software"), to deal in the Software without restriction, including
8 without limitation the rights to use, copy, modify, merge, publish,
9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12 
13 The above copyright notice and this permission notice shall be
14 included in all copies or substantial portions of the Software.
15 
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
23 
24 #include <elf.h>
25 
26 #include "_UCD_lib.h"
27 #include "_UCD_internal.h"
28 
29 static int
get_unwind_info(struct UCD_info * ui,unw_addr_space_t as,unw_word_t ip)30 get_unwind_info(struct UCD_info *ui, unw_addr_space_t as, unw_word_t ip)
31 {
32   unsigned long segbase, mapoff;
33 
34 #if UNW_TARGET_IA64 && defined(__linux)
35   if (!ui->edi.ktab.start_ip && _Uia64_get_kernel_table (&ui->edi.ktab) < 0)
36     return -UNW_ENOINFO;
37 
38   if (ui->edi.ktab.format != -1 && ip >= ui->edi.ktab.start_ip && ip < ui->edi.ktab.end_ip)
39     return 0;
40 #endif
41 
42   if ((ui->edi.di_cache.format != -1
43        && ip >= ui->edi.di_cache.start_ip && ip < ui->edi.di_cache.end_ip)
44 #if UNW_TARGET_ARM
45       || (ui->edi.di_debug.format != -1
46        && ip >= ui->edi.di_arm.start_ip && ip < ui->edi.di_arm.end_ip)
47 #endif
48       || (ui->edi.di_debug.format != -1
49        && ip >= ui->edi.di_debug.start_ip && ip < ui->edi.di_debug.end_ip))
50     return 0;
51 
52   invalidate_edi (&ui->edi);
53 
54   /* Used to be tdep_get_elf_image() in ptrace unwinding code */
55   coredump_phdr_t *phdr = _UCD_get_elf_image(ui, ip);
56   if (!phdr)
57     {
58       Debug(1, "returns error: _UCD_get_elf_image failed\n");
59       return -UNW_ENOINFO;
60     }
61   /* segbase: where it is mapped in virtual memory */
62   /* mapoff: offset in the file */
63   segbase = phdr->p_vaddr;
64   /*mapoff  = phdr->p_offset; WRONG! phdr->p_offset is the offset in COREDUMP file */
65   mapoff  = 0;
66 ///FIXME. text segment is USUALLY, not always, at offset 0 in the binary/.so file.
67 // ensure that at initialization.
68 
69   /* Here, SEGBASE is the starting-address of the (mmap'ped) segment
70      which covers the IP we're looking for.  */
71   if (tdep_find_unwind_table(&ui->edi, as, phdr->backing_filename, segbase, mapoff, ip) < 0)
72     {
73       Debug(1, "returns error: tdep_find_unwind_table failed\n");
74       return -UNW_ENOINFO;
75     }
76 
77   /* This can happen in corner cases where dynamically generated
78      code falls into the same page that contains the data-segment
79      and the page-offset of the code is within the first page of
80      the executable.  */
81   if (ui->edi.di_cache.format != -1
82       && (ip < ui->edi.di_cache.start_ip || ip >= ui->edi.di_cache.end_ip))
83      ui->edi.di_cache.format = -1;
84 
85   if (ui->edi.di_debug.format != -1
86       && (ip < ui->edi.di_debug.start_ip || ip >= ui->edi.di_debug.end_ip))
87      ui->edi.di_debug.format = -1;
88 
89   if (ui->edi.di_cache.format == -1
90 #if UNW_TARGET_ARM
91       && ui->edi.di_arm.format == -1
92 #endif
93       && ui->edi.di_debug.format == -1)
94   {
95     Debug(1, "returns error: all formats are -1\n");
96     return -UNW_ENOINFO;
97   }
98 
99   Debug(1, "returns success\n");
100   return 0;
101 }
102 
103 int
_UCD_find_proc_info(unw_addr_space_t as,unw_word_t ip,unw_proc_info_t * pi,int need_unwind_info,void * arg)104 _UCD_find_proc_info (unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
105 		     int need_unwind_info, void *arg)
106 {
107   struct UCD_info *ui = arg;
108 
109   Debug(1, "entering\n");
110 
111   int ret = -UNW_ENOINFO;
112 
113   if (get_unwind_info(ui, as, ip) < 0) {
114     Debug(1, "returns error: get_unwind_info failed\n");
115     return -UNW_ENOINFO;
116   }
117 
118 #if UNW_TARGET_IA64
119   if (ui->edi.ktab.format != -1)
120     {
121       /* The kernel unwind table resides in local memory, so we have
122 	 to use the local address space to search it.  Since
123 	 _UCD_put_unwind_info() has no easy way of detecting this
124 	 case, we simply make a copy of the unwind-info, so
125 	 _UCD_put_unwind_info() can always free() the unwind-info
126 	 without ill effects.  */
127       ret = tdep_search_unwind_table (unw_local_addr_space, ip, &ui->edi.ktab, pi,
128 				      need_unwind_info, arg);
129       if (ret >= 0)
130 	{
131 	  if (!need_unwind_info)
132 	    pi->unwind_info = NULL;
133 	  else
134 	    {
135 	      void *mem = malloc (pi->unwind_info_size);
136 
137 	      if (!mem)
138 		return -UNW_ENOMEM;
139 	      memcpy (mem, pi->unwind_info, pi->unwind_info_size);
140 	      pi->unwind_info = mem;
141 	    }
142 	}
143     }
144 #endif
145 
146   if (ret == -UNW_ENOINFO && ui->edi.di_cache.format != -1)
147     ret = tdep_search_unwind_table (as, ip, &ui->edi.di_cache,
148 				    pi, need_unwind_info, arg);
149 
150 #if UNW_TARGET_ARM
151   if (ret == -UNW_ENOINFO && ui->edi.di_arm.format != -1)
152     ret = tdep_search_unwind_table (as, ip, &ui->edi.di_arm, pi,
153                                     need_unwind_info, arg);
154 #endif
155 
156   if (ret == -UNW_ENOINFO && ui->edi.di_debug.format != -1)
157     ret = tdep_search_unwind_table (as, ip, &ui->edi.di_debug, pi,
158 				    need_unwind_info, arg);
159 
160   Debug(1, "returns %d\n", ret);
161 
162   return ret;
163 }
164