| /* 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" |
| |
| static bool get_dyn_gp(struct elf_image* ei, Elf_W(Off) dyn_phdr_offset, unw_word_t* gp) { |
| Elf_W(Phdr) phdr; |
| GET_PHDR_FIELD(ei, dyn_phdr_offset, &phdr, p_offset); |
| Elf_W(Dyn) dyn; |
| Elf_W(Off) dyn_offset = phdr.p_offset; |
| unw_word_t map_size = ei->u.memory.end - ei->u.memory.start; |
| while (dyn_offset + sizeof(dyn) < map_size) { |
| GET_DYN_FIELD(ei, dyn_offset, &dyn, d_tag); |
| if (dyn.d_tag == DT_NULL) { |
| break; |
| } |
| if (dyn.d_tag == DT_PLTGOT) { |
| // Assume that _DYNAMIC is writable and GLIBC has |
| // relocated it (true for x86 at least). |
| GET_DYN_FIELD(ei, dyn_offset, &dyn, d_un.d_ptr); |
| *gp = dyn.d_un.d_ptr; |
| return true; |
| } |
| dyn_offset += sizeof(dyn); |
| } |
| Debug(1, "DT_PLTGOT not found in dynamic header\n"); |
| return false; |
| } |
| |
| static bool get_eh_frame_info( |
| struct elf_image* ei, unw_word_t phdr_offset, unw_word_t load_base, unw_dyn_info_t* di_cache) { |
| Elf_W(Phdr) phdr; |
| GET_PHDR_FIELD(ei, phdr_offset, &phdr, p_offset); |
| unw_word_t hdr_offset = phdr.p_offset; |
| struct dwarf_eh_frame_hdr hdr; |
| // Read the entire hdr since we are going to use every value in the struct. |
| if (sizeof(hdr) != elf_w (memory_read) (ei, ei->u.memory.start + phdr.p_offset, |
| (uint8_t*) &hdr, sizeof(hdr), false)) { |
| Debug(1, "Failed to read dwarf_eh_frame_hdr from in memory elf image.\n"); |
| return false; |
| } |
| |
| if (hdr.version != DW_EH_VERSION) { |
| Debug (1, "table has unexpected version %d\n", hdr.version); |
| return false; |
| } |
| |
| // Fill in a dummy proc_info structure. We just need to fill in |
| // enough to ensure that dwarf_read_encoded_pointer() can do its |
| // job. Since we don't have a procedure-context at this point, all |
| // we have to do is fill in the global-pointer. |
| unw_proc_info_t pi; |
| memset (&pi, 0, sizeof (pi)); |
| pi.gp = di_cache->gp; |
| |
| unw_accessors_t* a = unw_get_accessors (ei->u.memory.as); |
| unw_word_t addr = (unw_word_t) (uintptr_t) (hdr_offset + sizeof(struct dwarf_eh_frame_hdr)); |
| addr += ei->u.memory.start; |
| |
| unw_word_t eh_frame_start; |
| if (dwarf_read_encoded_pointer (ei->u.memory.as, a, &addr, hdr.eh_frame_ptr_enc, &pi, |
| &eh_frame_start, ei->u.memory.as_arg) < 0) { |
| Debug(1, "Failed to read encoded frame start.\n"); |
| return false; |
| } |
| |
| unw_word_t fde_count; |
| if (dwarf_read_encoded_pointer (ei->u.memory.as, a, &addr, hdr.fde_count_enc, &pi, |
| &fde_count, ei->u.memory.as_arg) < 0) { |
| Debug(1, "Failed to read fde count.\n"); |
| return false; |
| } |
| |
| if (hdr.table_enc != (DW_EH_PE_datarel | DW_EH_PE_sdata4)) { |
| // Unsupported table format. |
| Debug(1, "Unsupported header table format %d\n", hdr.table_enc); |
| return false; |
| } |
| |
| di_cache->u.rti.name_ptr = 0; |
| // two 32-bit values (ip_offset/fde_offset) per table-entry: |
| di_cache->u.rti.table_len = (fde_count * 8) / sizeof (unw_word_t); |
| |
| GET_PHDR_FIELD(ei, phdr_offset, &phdr, p_vaddr); |
| GET_PHDR_FIELD(ei, phdr_offset, &phdr, p_offset); |
| di_cache->u.rti.table_data = |
| load_base + phdr.p_vaddr + addr - (uintptr_t) ei->u.memory.start - phdr.p_offset; |
| |
| // For the binary-search table in the eh_frame_hdr, data-relative |
| // means relative to the start of that section... |
| di_cache->u.rti.segbase = ((load_base + phdr.p_vaddr) + (hdr_offset - phdr.p_offset)); |
| |
| return true; |
| } |
| |
| static bool dwarf_find_unwind_table_memory ( |
| struct elf_dyn_info *edi, struct elf_image *ei, unw_addr_space_t as, char *path, |
| unw_word_t segbase, unw_word_t mapoff, unw_word_t ip) { |
| Elf_W(Ehdr) ehdr; |
| GET_EHDR_FIELD(ei, &ehdr, e_phoff, false); |
| GET_EHDR_FIELD(ei, &ehdr, e_phnum, false); |
| |
| Elf_W(Off) offset = ehdr.e_phoff; |
| Elf_W(Off) txt_phdr_offset = 0; |
| Elf_W(Addr) txt_pvaddr = 0; |
| Elf_W(Off) dyn_phdr_offset = 0; |
| #if UNW_TARGET_ARM |
| Elf_W(Off) arm_exidx_phdr_offset = 0; |
| #endif |
| int i; |
| unw_word_t start_ip = (unw_word_t) -1; |
| unw_word_t end_ip = 0; |
| Elf_W(Off) eh_frame_phdr_offset = 0; |
| for (i = 0; i < ehdr.e_phnum; ++i) { |
| Elf_W(Phdr) phdr; |
| GET_PHDR_FIELD(ei, offset, &phdr, p_type); |
| switch (phdr.p_type) { |
| case PT_LOAD: |
| GET_PHDR_FIELD(ei, offset, &phdr, p_vaddr); |
| if (phdr.p_vaddr < start_ip) { |
| start_ip = phdr.p_vaddr; |
| } |
| |
| GET_PHDR_FIELD(ei, offset, &phdr, p_memsz); |
| if (phdr.p_vaddr + phdr.p_memsz > end_ip) { |
| end_ip = phdr.p_vaddr + phdr.p_memsz; |
| } |
| |
| GET_PHDR_FIELD(ei, offset, &phdr, p_offset); |
| if (phdr.p_offset == mapoff) { |
| txt_phdr_offset = offset; |
| txt_pvaddr = phdr.p_vaddr; |
| } |
| break; |
| |
| case PT_GNU_EH_FRAME: |
| eh_frame_phdr_offset = offset; |
| break; |
| |
| case PT_DYNAMIC: |
| dyn_phdr_offset = offset; |
| break; |
| |
| #if UNW_TARGET_ARM |
| case PT_ARM_EXIDX: |
| arm_exidx_phdr_offset = offset; |
| break; |
| #endif |
| |
| default: |
| break; |
| } |
| offset += sizeof(phdr); |
| } |
| |
| if (txt_phdr_offset == 0) { |
| Debug(1, "PT_LOAD section not found.\n"); |
| return false; |
| } |
| |
| unw_word_t load_base = segbase - txt_pvaddr; |
| start_ip += load_base; |
| end_ip += load_base; |
| |
| bool found = false; |
| if (eh_frame_phdr_offset) { |
| // 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". |
| // 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; |
| if (dyn_phdr_offset) { |
| // Ignore failures, we'll attempt to keep going with a zero gp. |
| get_dyn_gp(ei, dyn_phdr_offset, &edi->di_cache.gp); |
| } |
| |
| found = get_eh_frame_info(ei, eh_frame_phdr_offset, load_base, &edi->di_cache); |
| if (found) { |
| edi->di_cache.start_ip = start_ip; |
| edi->di_cache.end_ip = end_ip; |
| edi->di_cache.format = UNW_INFO_FORMAT_REMOTE_TABLE; |
| } |
| } |
| |
| #if UNW_TARGET_ARM |
| // Verify that the map contains enough space for the arm unwind data. |
| if (arm_exidx_phdr_offset && |
| arm_exidx_phdr_offset + sizeof(Elf_W(Phdr)) < ei->u.memory.end - ei->u.memory.start) { |
| Elf_W(Phdr) phdr; |
| GET_PHDR_FIELD(ei, arm_exidx_phdr_offset, &phdr, p_vaddr); |
| GET_PHDR_FIELD(ei, arm_exidx_phdr_offset, &phdr, p_memsz); |
| edi->di_arm.u.rti.table_data = load_base + phdr.p_vaddr; |
| edi->di_arm.u.rti.table_len = phdr.p_memsz; |
| |
| 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 = (unw_word_t) path; |
| found = true; |
| } |
| #endif |
| |
| return found; |
| } |
| |
| int |
| dwarf_find_unwind_table (struct elf_dyn_info *edi, struct elf_image *ei, |
| 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; |
| #if 0 |
| // Not currently used. |
| unw_word_t max_load_addr = 0; |
| #endif |
| unw_word_t start_ip = (unw_word_t) -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 (!ei->valid) |
| return -UNW_ENOINFO; |
| |
| if (!ei->mapped) { |
| if (dwarf_find_unwind_table_memory (edi, ei, as, path, segbase, mapoff, ip)) { |
| return 1; |
| } |
| return -UNW_ENOINFO; |
| } |
| |
| /* ANDROID support update. */ |
| ehdr = ei->u.mapped.image; |
| phdr = (Elf_W(Phdr) *) ((char *) ei->u.mapped.image + ehdr->e_phoff); |
| /* End of ANDROID update. */ |
| |
| 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 0 |
| // Not currently used. |
| if ((uintptr_t) ei->u.mapped.image + phdr->p_filesz > max_load_addr) |
| max_load_addr = (uintptr_t) ei->u.mapped.image + phdr->p_filesz; |
| #endif |
| 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) |
| { |
| // 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". |
| // 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; |
| if (pdyn) { |
| Elf_W(Dyn) *dyn = (Elf_W(Dyn) *)(pdyn->p_offset + (char *) ei->u.mapped.image); |
| while ((char*) dyn - (char*) ei->u.mapped.image + sizeof(Elf_W(Dyn)) < ei->u.mapped.size |
| && dyn->d_tag != DT_NULL) { |
| 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; |
| } |
| dyn++; |
| } |
| } |
| |
| /* ANDROID support update. */ |
| hdr = (struct dwarf_eh_frame_hdr *) (peh_hdr->p_offset |
| + (char *) ei->u.mapped.image); |
| /* End of ANDROID update. */ |
| 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 (unw_local_addr_space); |
| /* ANDROID support update. */ |
| addr = (unw_word_t) (uintptr_t) (hdr + 1); |
| /* End of ANDROID update. */ |
| |
| /* Fill in a dummy proc_info structure. We just need to fill in |
| enough to ensure that dwarf_read_encoded_pointer() can do its |
| 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; |
| |
| 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; |
| |
| 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 |
| // Right now do nothing. |
| //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 |
| } |
| else |
| { |
| 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); |
| /* ANDROID support update. */ |
| edi->di_cache.u.rti.table_data = ((load_base + peh_hdr->p_vaddr) |
| + (addr - (uintptr_t) ei->u.mapped.image |
| - peh_hdr->p_offset)); |
| /* End of ANDROID update. */ |
| |
| /* For the binary-search table in the eh_frame_hdr, data-relative |
| means relative to the start of that section... */ |
| |
| /* ANDROID support update. */ |
| edi->di_cache.u.rti.segbase = ((load_base + peh_hdr->p_vaddr) |
| + ((uintptr_t) hdr - (uintptr_t) ei->u.mapped.image |
| - peh_hdr->p_offset)); |
| /* End of ANDROID update. */ |
| 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 = (unw_word_t) 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; |
| } |