| /* libunwind - a platform-independent unwind library |
| Copyright (C) 2003-2004 Hewlett-Packard Co |
| Contributed by David Mosberger-Tang <davidm@hpl.hp.com> |
| |
| This file is part of libunwind. |
| |
| Permission is hereby granted, free of charge, to any person obtaining |
| a copy of this software and associated documentation files (the |
| "Software"), to deal in the Software without restriction, including |
| without limitation the rights to use, copy, modify, merge, publish, |
| distribute, sublicense, and/or sell copies of the Software, and to |
| permit persons to whom the Software is furnished to do so, subject to |
| the following conditions: |
| |
| The above copyright notice and this permission notice shall be |
| included in all copies or substantial portions of the Software. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
| LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
| OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
| WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ |
| |
| #include <fcntl.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include <sys/mman.h> |
| |
| #include "libunwind_i.h" |
| #include "dwarf-eh.h" |
| #include "dwarf_i.h" |
| |
| #define to_unw_word(p) ((unw_word_t) (uintptr_t) (p)) |
| |
| int |
| dwarf_find_unwind_table (struct elf_dyn_info *edi, unw_addr_space_t as, |
| char *path, unw_word_t segbase, unw_word_t mapoff, |
| unw_word_t ip) |
| { |
| Elf_W(Phdr) *phdr, *ptxt = NULL, *peh_hdr = NULL, *pdyn = NULL; |
| unw_word_t addr, eh_frame_start, fde_count, load_base; |
| unw_word_t max_load_addr = 0; |
| unw_word_t start_ip = to_unw_word (-1); |
| unw_word_t end_ip = 0; |
| struct dwarf_eh_frame_hdr *hdr; |
| unw_proc_info_t pi; |
| unw_accessors_t *a; |
| Elf_W(Ehdr) *ehdr; |
| #if UNW_TARGET_ARM |
| const Elf_W(Phdr) *parm_exidx = NULL; |
| #endif |
| int i, ret, found = 0; |
| |
| /* XXX: Much of this code is Linux/LSB-specific. */ |
| |
| if (!elf_w(valid_object) (&edi->ei)) |
| return -UNW_ENOINFO; |
| |
| ehdr = edi->ei.image; |
| phdr = (Elf_W(Phdr) *) ((char *) edi->ei.image + ehdr->e_phoff); |
| |
| for (i = 0; i < ehdr->e_phnum; ++i) |
| { |
| switch (phdr[i].p_type) |
| { |
| case PT_LOAD: |
| if (phdr[i].p_vaddr < start_ip) |
| start_ip = phdr[i].p_vaddr; |
| |
| if (phdr[i].p_vaddr + phdr[i].p_memsz > end_ip) |
| end_ip = phdr[i].p_vaddr + phdr[i].p_memsz; |
| |
| if (phdr[i].p_offset == mapoff) |
| ptxt = phdr + i; |
| if ((uintptr_t) edi->ei.image + phdr->p_filesz > max_load_addr) |
| max_load_addr = (uintptr_t) edi->ei.image + phdr->p_filesz; |
| break; |
| |
| case PT_GNU_EH_FRAME: |
| peh_hdr = phdr + i; |
| break; |
| |
| case PT_DYNAMIC: |
| pdyn = phdr + i; |
| break; |
| |
| #if UNW_TARGET_ARM |
| case PT_ARM_EXIDX: |
| parm_exidx = phdr + i; |
| break; |
| #endif |
| |
| default: |
| break; |
| } |
| } |
| |
| if (!ptxt) |
| return 0; |
| |
| load_base = segbase - ptxt->p_vaddr; |
| start_ip += load_base; |
| end_ip += load_base; |
| |
| if (peh_hdr) |
| { |
| if (pdyn) |
| { |
| /* For dynamicly linked executables and shared libraries, |
| DT_PLTGOT is the value that data-relative addresses are |
| relative to for that object. We call this the "gp". */ |
| Elf_W(Dyn) *dyn = (Elf_W(Dyn) *)(pdyn->p_offset |
| + (char *) edi->ei.image); |
| for (; dyn->d_tag != DT_NULL; ++dyn) |
| if (dyn->d_tag == DT_PLTGOT) |
| { |
| /* Assume that _DYNAMIC is writable and GLIBC has |
| relocated it (true for x86 at least). */ |
| edi->di_cache.gp = dyn->d_un.d_ptr; |
| break; |
| } |
| } |
| else |
| /* Otherwise this is a static executable with no _DYNAMIC. Assume |
| that data-relative addresses are relative to 0, i.e., |
| absolute. */ |
| edi->di_cache.gp = 0; |
| |
| hdr = (struct dwarf_eh_frame_hdr *) (peh_hdr->p_offset |
| + (char *) edi->ei.image); |
| if (hdr->version != DW_EH_VERSION) |
| { |
| Debug (1, "table `%s' has unexpected version %d\n", |
| path, hdr->version); |
| return -UNW_ENOINFO; |
| } |
| |
| a = unw_get_accessors_int (unw_local_addr_space); |
| addr = to_unw_word (&hdr->eh_frame); |
| |
| /* Fill in a dummy proc_info structure. We just need to fill in |
| enough to ensure that dwarf_read_encoded_pointer() can do it's |
| job. Since we don't have a procedure-context at this point, all |
| we have to do is fill in the global-pointer. */ |
| memset (&pi, 0, sizeof (pi)); |
| pi.gp = edi->di_cache.gp; |
| |
| /* (Optionally) read eh_frame_ptr: */ |
| if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a, |
| &addr, hdr->eh_frame_ptr_enc, &pi, |
| &eh_frame_start, NULL)) < 0) |
| return -UNW_ENOINFO; |
| |
| /* (Optionally) read fde_count: */ |
| if ((ret = dwarf_read_encoded_pointer (unw_local_addr_space, a, |
| &addr, hdr->fde_count_enc, &pi, |
| &fde_count, NULL)) < 0) |
| return -UNW_ENOINFO; |
| |
| if (hdr->table_enc != (DW_EH_PE_datarel | DW_EH_PE_sdata4)) |
| { |
| #if 1 |
| abort (); |
| #else |
| unw_word_t eh_frame_end; |
| |
| /* If there is no search table or it has an unsupported |
| encoding, fall back on linear search. */ |
| if (hdr->table_enc == DW_EH_PE_omit) |
| Debug (4, "EH lacks search table; doing linear search\n"); |
| else |
| Debug (4, "EH table has encoding 0x%x; doing linear search\n", |
| hdr->table_enc); |
| |
| eh_frame_end = max_load_addr; /* XXX can we do better? */ |
| |
| if (hdr->fde_count_enc == DW_EH_PE_omit) |
| fde_count = ~0UL; |
| if (hdr->eh_frame_ptr_enc == DW_EH_PE_omit) |
| abort (); |
| |
| return linear_search (unw_local_addr_space, ip, |
| eh_frame_start, eh_frame_end, fde_count, |
| pi, need_unwind_info, NULL); |
| #endif |
| } |
| |
| edi->di_cache.start_ip = start_ip; |
| edi->di_cache.end_ip = end_ip; |
| edi->di_cache.format = UNW_INFO_FORMAT_REMOTE_TABLE; |
| edi->di_cache.u.rti.name_ptr = 0; |
| /* two 32-bit values (ip_offset/fde_offset) per table-entry: */ |
| edi->di_cache.u.rti.table_len = (fde_count * 8) / sizeof (unw_word_t); |
| edi->di_cache.u.rti.table_data = ((load_base + peh_hdr->p_vaddr) |
| + (addr - to_unw_word (edi->ei.image) |
| - peh_hdr->p_offset)); |
| |
| /* For the binary-search table in the eh_frame_hdr, data-relative |
| means relative to the start of that section... */ |
| edi->di_cache.u.rti.segbase = ((load_base + peh_hdr->p_vaddr) |
| + (to_unw_word (hdr) - |
| to_unw_word (edi->ei.image) |
| - peh_hdr->p_offset)); |
| found = 1; |
| } |
| |
| #if UNW_TARGET_ARM |
| if (parm_exidx) |
| { |
| edi->di_arm.format = UNW_INFO_FORMAT_ARM_EXIDX; |
| edi->di_arm.start_ip = start_ip; |
| edi->di_arm.end_ip = end_ip; |
| edi->di_arm.u.rti.name_ptr = to_unw_word (path); |
| edi->di_arm.u.rti.table_data = load_base + parm_exidx->p_vaddr; |
| edi->di_arm.u.rti.table_len = parm_exidx->p_memsz; |
| found = 1; |
| } |
| #endif |
| |
| #ifdef CONFIG_DEBUG_FRAME |
| /* Try .debug_frame. */ |
| found = dwarf_find_debug_frame (found, &edi->di_debug, ip, load_base, path, |
| start_ip, end_ip); |
| #endif |
| |
| return found; |
| } |
