1 /* libunwind - a platform-independent unwind library 2 Copyright (C) 2003-2004 Hewlett-Packard Co 3 Contributed by David Mosberger-Tang <davidm (at) hpl.hp.com> 4 5 This file is part of libunwind. 6 7 Permission is hereby granted, free of charge, to any person obtaining 8 a copy of this software and associated documentation files (the 9 "Software"), to deal in the Software without restriction, including 10 without limitation the rights to use, copy, modify, merge, publish, 11 distribute, sublicense, and/or sell copies of the Software, and to 12 permit persons to whom the Software is furnished to do so, subject to 13 the following conditions: 14 15 The above copyright notice and this permission notice shall be 16 included in all copies or substantial portions of the Software. 17 18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 25 26 #include <fcntl.h> 27 #include <string.h> 28 #include <unistd.h> 29 30 #include <sys/mman.h> 31 32 #include "libunwind_i.h" 33 #include "dwarf-eh.h" 34 #include "dwarf_i.h" 35 36 /* ANDROID support update. */ 37 int 38 dwarf_find_unwind_table (struct elf_dyn_info *edi, struct elf_image *ei, 39 unw_addr_space_t as, char *path, 40 unw_word_t segbase, unw_word_t mapoff, unw_word_t ip) 41 /* End of ANDROID update. */ 42 { 43 Elf_W(Phdr) *phdr, *ptxt = NULL, *peh_hdr = NULL, *pdyn = NULL; 44 unw_word_t addr, eh_frame_start, fde_count, load_base; 45 unw_word_t max_load_addr = 0; 46 unw_word_t start_ip = (unw_word_t) -1; 47 unw_word_t end_ip = 0; 48 struct dwarf_eh_frame_hdr *hdr; 49 unw_proc_info_t pi; 50 unw_accessors_t *a; 51 Elf_W(Ehdr) *ehdr; 52 #if UNW_TARGET_ARM 53 const Elf_W(Phdr) *parm_exidx = NULL; 54 #endif 55 int i, ret, found = 0; 56 57 /* XXX: Much of this code is Linux/LSB-specific. */ 58 59 /* ANDROID support update. */ 60 if (!elf_w(valid_object) (ei)) 61 /* End of ANDROID update. */ 62 return -UNW_ENOINFO; 63 64 /* ANDROID support update. */ 65 ehdr = ei->image; 66 phdr = (Elf_W(Phdr) *) ((char *) ei->image + ehdr->e_phoff); 67 /* End of ANDROID update. */ 68 69 for (i = 0; i < ehdr->e_phnum; ++i) 70 { 71 switch (phdr[i].p_type) 72 { 73 case PT_LOAD: 74 if (phdr[i].p_vaddr < start_ip) 75 start_ip = phdr[i].p_vaddr; 76 77 if (phdr[i].p_vaddr + phdr[i].p_memsz > end_ip) 78 end_ip = phdr[i].p_vaddr + phdr[i].p_memsz; 79 80 if (phdr[i].p_offset == mapoff) 81 ptxt = phdr + i; 82 83 /* ANDROID support update. */ 84 if ((uintptr_t) ei->image + phdr->p_filesz > max_load_addr) 85 max_load_addr = (uintptr_t) ei->image + phdr->p_filesz; 86 break; 87 /* End of ANDROID update. */ 88 89 case PT_GNU_EH_FRAME: 90 peh_hdr = phdr + i; 91 break; 92 93 case PT_DYNAMIC: 94 pdyn = phdr + i; 95 break; 96 97 #if UNW_TARGET_ARM 98 case PT_ARM_EXIDX: 99 parm_exidx = phdr + i; 100 break; 101 #endif 102 103 default: 104 break; 105 } 106 } 107 108 if (!ptxt) 109 return 0; 110 111 load_base = segbase - ptxt->p_vaddr; 112 start_ip += load_base; 113 end_ip += load_base; 114 115 if (peh_hdr) 116 { 117 if (pdyn) 118 { 119 /* For dynamicly linked executables and shared libraries, 120 DT_PLTGOT is the value that data-relative addresses are 121 relative to for that object. We call this the "gp". */ 122 /* ANDROID support update. */ 123 Elf_W(Dyn) *dyn = (Elf_W(Dyn) *)(pdyn->p_offset 124 + (char *) ei->image); 125 /* End of ANDROID update. */ 126 for (; dyn->d_tag != DT_NULL; ++dyn) 127 if (dyn->d_tag == DT_PLTGOT) 128 { 129 /* Assume that _DYNAMIC is writable and GLIBC has 130 relocated it (true for x86 at least). */ 131 edi->di_cache.gp = dyn->d_un.d_ptr; 132 break; 133 } 134 } 135 else 136 /* Otherwise this is a static executable with no _DYNAMIC. Assume 137 that data-relative addresses are relative to 0, i.e., 138 absolute. */ 139 edi->di_cache.gp = 0; 140 141 /* ANDROID support update. */ 142 hdr = (struct dwarf_eh_frame_hdr *) (peh_hdr->p_offset 143 + (char *) ei->image); 144 /* End of ANDROID update. */ 145 if (hdr->version != DW_EH_VERSION) 146 { 147 Debug (1, "table `%s' has unexpected version %d\n", 148 path, hdr->version); 149 return -UNW_ENOINFO; 150 } 151 152 a = unw_get_accessors (unw_local_addr_space); 153 /* ANDROID support update. */ 154 addr = (unw_word_t) (uintptr_t) (hdr + 1); 155 /* End of ANDROID update. */ 156 157 /* Fill in a dummy proc_info structure. We just need to fill in 158 enough to ensure that dwarf_read_encoded_pointer() can do it's 159 job. Since we don't have a procedure-context at this point, all 160 we have to do is fill in the global-pointer. */ 161 memset (&pi, 0, sizeof (pi)); 162 pi.gp = edi->di_cache.gp; 163 164 /* (Optionally) read eh_frame_ptr: */ 165 if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a, 166 &addr, hdr->eh_frame_ptr_enc, &pi, 167 &eh_frame_start, NULL)) < 0) 168 return -UNW_ENOINFO; 169 170 /* (Optionally) read fde_count: */ 171 if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a, 172 &addr, hdr->fde_count_enc, &pi, 173 &fde_count, NULL)) < 0) 174 return -UNW_ENOINFO; 175 176 if (hdr->table_enc != (DW_EH_PE_datarel | DW_EH_PE_sdata4)) 177 { 178 #if 1 179 abort (); 180 #else 181 unw_word_t eh_frame_end; 182 183 /* If there is no search table or it has an unsupported 184 encoding, fall back on linear search. */ 185 if (hdr->table_enc == DW_EH_PE_omit) 186 Debug (4, "EH lacks search table; doing linear search\n"); 187 else 188 Debug (4, "EH table has encoding 0x%x; doing linear search\n", 189 hdr->table_enc); 190 191 eh_frame_end = max_load_addr; /* XXX can we do better? */ 192 193 if (hdr->fde_count_enc == DW_EH_PE_omit) 194 fde_count = ~0UL; 195 if (hdr->eh_frame_ptr_enc == DW_EH_PE_omit) 196 abort (); 197 198 return linear_search (unw_local_addr_space, ip, 199 eh_frame_start, eh_frame_end, fde_count, 200 pi, need_unwind_info, NULL); 201 #endif 202 } 203 204 edi->di_cache.start_ip = start_ip; 205 edi->di_cache.end_ip = end_ip; 206 edi->di_cache.format = UNW_INFO_FORMAT_REMOTE_TABLE; 207 edi->di_cache.u.rti.name_ptr = 0; 208 /* two 32-bit values (ip_offset/fde_offset) per table-entry: */ 209 edi->di_cache.u.rti.table_len = (fde_count * 8) / sizeof (unw_word_t); 210 /* ANDROID support update. */ 211 edi->di_cache.u.rti.table_data = ((load_base + peh_hdr->p_vaddr) 212 + (addr - (uintptr_t) ei->image 213 - peh_hdr->p_offset)); 214 /* End of ANDROID update. */ 215 216 /* For the binary-search table in the eh_frame_hdr, data-relative 217 means relative to the start of that section... */ 218 219 /* ANDROID support update. */ 220 edi->di_cache.u.rti.segbase = ((load_base + peh_hdr->p_vaddr) 221 + ((uintptr_t) hdr - (uintptr_t) ei->image 222 - peh_hdr->p_offset)); 223 /* End of ANDROID update. */ 224 found = 1; 225 } 226 227 #if UNW_TARGET_ARM 228 if (parm_exidx) 229 { 230 edi->di_arm.format = UNW_INFO_FORMAT_ARM_EXIDX; 231 edi->di_arm.start_ip = start_ip; 232 edi->di_arm.end_ip = end_ip; 233 edi->di_arm.u.rti.name_ptr = (unw_word_t) path; 234 edi->di_arm.u.rti.table_data = load_base + parm_exidx->p_vaddr; 235 edi->di_arm.u.rti.table_len = parm_exidx->p_memsz; 236 found = 1; 237 } 238 #endif 239 240 #ifdef CONFIG_DEBUG_FRAME 241 /* Try .debug_frame. */ 242 found = dwarf_find_debug_frame (found, &edi->di_debug, ip, load_base, path, 243 start_ip, end_ip); 244 #endif 245 246 return found; 247 } 248
