| /* Report modules by examining dynamic linker data structures. |
| Copyright (C) 2008-2016 Red Hat, Inc. |
| Copyright (C) 2021 Mark J. Wielaard <[email protected]> |
| This file is part of elfutils. |
| |
| This file is free software; you can redistribute it and/or modify |
| it under the terms of either |
| |
| * the GNU Lesser General Public License as published by the Free |
| Software Foundation; either version 3 of the License, or (at |
| your option) any later version |
| |
| or |
| |
| * the GNU General Public License as published by the Free |
| Software Foundation; either version 2 of the License, or (at |
| your option) any later version |
| |
| or both in parallel, as here. |
| |
| elfutils is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received copies of the GNU General Public License and |
| the GNU Lesser General Public License along with this program. If |
| not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include <config.h> |
| #include "libdwflP.h" |
| #include "../libdw/memory-access.h" |
| #include "system.h" |
| |
| #include <fcntl.h> |
| |
| /* This element is always provided and always has a constant value. |
| This makes it an easy thing to scan for to discern the format. */ |
| #define PROBE_TYPE AT_PHENT |
| #define PROBE_VAL32 sizeof (Elf32_Phdr) |
| #define PROBE_VAL64 sizeof (Elf64_Phdr) |
| |
| |
| static inline bool |
| do_check64 (const char *a64, uint_fast8_t *elfdata) |
| { |
| /* The AUXV pointer might not even be naturally aligned for 64-bit |
| data, because note payloads in a core file are not aligned. */ |
| const char *typep = a64 + offsetof (Elf64_auxv_t, a_type); |
| uint64_t type = read_8ubyte_unaligned_noncvt (typep); |
| const char *valp = a64 + offsetof (Elf64_auxv_t, a_un.a_val); |
| uint64_t val = read_8ubyte_unaligned_noncvt (valp); |
| |
| if (type == BE64 (PROBE_TYPE) |
| && val == BE64 (PROBE_VAL64)) |
| { |
| *elfdata = ELFDATA2MSB; |
| return true; |
| } |
| |
| if (type == LE64 (PROBE_TYPE) |
| && val == LE64 (PROBE_VAL64)) |
| { |
| *elfdata = ELFDATA2LSB; |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static inline bool |
| do_check32 (const char *a32, uint_fast8_t *elfdata) |
| { |
| /* The AUXV pointer might not even be naturally aligned for 32-bit |
| data, because note payloads in a core file are not aligned. */ |
| const char *typep = a32 + offsetof (Elf32_auxv_t, a_type); |
| uint32_t type = read_4ubyte_unaligned_noncvt (typep); |
| const char *valp = a32 + offsetof (Elf32_auxv_t, a_un.a_val); |
| uint32_t val = read_4ubyte_unaligned_noncvt (valp); |
| |
| if (type == BE32 (PROBE_TYPE) |
| && val == BE32 (PROBE_VAL32)) |
| { |
| *elfdata = ELFDATA2MSB; |
| return true; |
| } |
| |
| if (type == LE32 (PROBE_TYPE) |
| && val == LE32 (PROBE_VAL32)) |
| { |
| *elfdata = ELFDATA2LSB; |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Examine an auxv data block and determine its format. |
| Return true iff we figured it out. */ |
| static bool |
| auxv_format_probe (const void *auxv, size_t size, |
| uint_fast8_t *elfclass, uint_fast8_t *elfdata) |
| { |
| for (size_t i = 0; i < size / sizeof (Elf64_auxv_t); ++i) |
| { |
| if (do_check64 (auxv + i * sizeof (Elf64_auxv_t), elfdata)) |
| { |
| *elfclass = ELFCLASS64; |
| return true; |
| } |
| |
| if (do_check32 (auxv + (i * 2) * sizeof (Elf32_auxv_t), elfdata) |
| || do_check32 (auxv + (i * 2 + 1) * sizeof (Elf32_auxv_t), elfdata)) |
| { |
| *elfclass = ELFCLASS32; |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* This is a Dwfl_Memory_Callback that wraps another memory callback. |
| If the underlying callback cannot fill the data, then this will |
| fall back to fetching data from module files. */ |
| |
| struct integrated_memory_callback |
| { |
| Dwfl_Memory_Callback *memory_callback; |
| void *memory_callback_arg; |
| void *buffer; |
| }; |
| |
| static bool |
| integrated_memory_callback (Dwfl *dwfl, int ndx, |
| void **buffer, size_t *buffer_available, |
| GElf_Addr vaddr, |
| size_t minread, |
| void *arg) |
| { |
| struct integrated_memory_callback *info = arg; |
| |
| if (ndx == -1) |
| { |
| /* Called for cleanup. */ |
| if (info->buffer != NULL) |
| { |
| /* The last probe buffer came from the underlying callback. |
| Let it do its cleanup. */ |
| assert (*buffer == info->buffer); /* XXX */ |
| *buffer = info->buffer; |
| info->buffer = NULL; |
| return (*info->memory_callback) (dwfl, ndx, buffer, buffer_available, |
| vaddr, minread, |
| info->memory_callback_arg); |
| } |
| *buffer = NULL; |
| *buffer_available = 0; |
| return false; |
| } |
| |
| if (*buffer != NULL) |
| /* For a final-read request, we only use the underlying callback. */ |
| return (*info->memory_callback) (dwfl, ndx, buffer, buffer_available, |
| vaddr, minread, info->memory_callback_arg); |
| |
| /* Let the underlying callback try to fill this request. */ |
| if ((*info->memory_callback) (dwfl, ndx, &info->buffer, buffer_available, |
| vaddr, minread, info->memory_callback_arg)) |
| { |
| *buffer = info->buffer; |
| return true; |
| } |
| |
| /* Now look for module text covering this address. */ |
| |
| Dwfl_Module *mod; |
| (void) INTUSE(dwfl_addrsegment) (dwfl, vaddr, &mod); |
| if (mod == NULL) |
| return false; |
| |
| Dwarf_Addr bias; |
| Elf_Scn *scn = INTUSE(dwfl_module_address_section) (mod, &vaddr, &bias); |
| if (unlikely (scn == NULL)) |
| { |
| #if 0 // XXX would have to handle ndx=-1 cleanup calls passed down. |
| /* If we have no sections we can try to fill it from the module file |
| based on its phdr mappings. */ |
| if (likely (mod->e_type != ET_REL) && mod->main.elf != NULL) |
| return INTUSE(dwfl_elf_phdr_memory_callback) |
| (dwfl, 0, buffer, buffer_available, |
| vaddr - mod->main.bias, minread, mod->main.elf); |
| #endif |
| return false; |
| } |
| |
| Elf_Data *data = elf_rawdata (scn, NULL); |
| if (unlikely (data == NULL)) |
| // XXX throw error? |
| return false; |
| |
| if (unlikely (data->d_size < vaddr)) |
| return false; |
| |
| /* Provide as much data as we have. */ |
| void *contents = data->d_buf + vaddr; |
| size_t avail = data->d_size - vaddr; |
| if (unlikely (avail < minread)) |
| return false; |
| |
| /* If probing for a string, make sure it's terminated. */ |
| if (minread == 0 && unlikely (memchr (contents, '\0', avail) == NULL)) |
| return false; |
| |
| /* We have it! */ |
| *buffer = contents; |
| *buffer_available = avail; |
| return true; |
| } |
| |
| static size_t |
| addrsize (uint_fast8_t elfclass) |
| { |
| return elfclass * 4; |
| } |
| |
| struct memory_closure |
| { |
| Dwfl *dwfl; |
| Dwfl_Memory_Callback *callback; |
| void *arg; |
| }; |
| |
| static inline int |
| release_buffer (struct memory_closure *closure, |
| void **buffer, size_t *buffer_available, int result) |
| { |
| if (*buffer != NULL) |
| (*closure->callback) (closure->dwfl, -1, buffer, buffer_available, 0, 0, |
| closure->arg); |
| |
| return result; |
| } |
| |
| static inline bool |
| read_addrs (struct memory_closure *closure, |
| uint_fast8_t elfclass, uint_fast8_t elfdata, |
| void **buffer, size_t *buffer_available, |
| GElf_Addr vaddr, GElf_Addr *read_vaddr, |
| size_t n, GElf_Addr *addrs /* [4] */) |
| { |
| size_t nb = n * addrsize (elfclass); /* Address words -> bytes to read. */ |
| Dwfl *dwfl = closure->dwfl; |
| |
| /* Read a new buffer if the old one doesn't cover these words. */ |
| if (*buffer == NULL |
| || vaddr < *read_vaddr |
| || nb > *buffer_available |
| || vaddr - (*read_vaddr) > *buffer_available - nb) |
| { |
| release_buffer (closure, buffer, buffer_available, 0); |
| |
| *read_vaddr = vaddr; |
| int segndx = INTUSE(dwfl_addrsegment) (dwfl, vaddr, NULL); |
| if (unlikely (segndx < 0) |
| || unlikely (! (*closure->callback) (dwfl, segndx, |
| buffer, buffer_available, |
| vaddr, nb, closure->arg))) |
| return true; |
| } |
| |
| unsigned char *addr = vaddr - (*read_vaddr) + (*buffer); |
| |
| if (elfclass == ELFCLASS32) |
| { |
| if (elfdata == ELFDATA2MSB) |
| for (size_t i = 0; i < n; ++i) |
| addrs[i] = BE32 (read_4ubyte_unaligned_noncvt (addr + i * 4)); |
| else |
| for (size_t i = 0; i < n; ++i) |
| addrs[i] = LE32 (read_4ubyte_unaligned_noncvt (addr + i * 4)); |
| } |
| else |
| { |
| if (elfdata == ELFDATA2MSB) |
| for (size_t i = 0; i < n; ++i) |
| addrs[i] = BE64 (read_8ubyte_unaligned_noncvt (addr + i * 8)); |
| else |
| for (size_t i = 0; i < n; ++i) |
| addrs[i] = LE64 (read_8ubyte_unaligned_noncvt (addr + i * 8)); |
| } |
| |
| return false; |
| } |
| |
| /* Report a module for each struct link_map in the linked list at r_map |
| in the struct r_debug at R_DEBUG_VADDR. For r_debug_info description |
| see dwfl_link_map_report in libdwflP.h. If R_DEBUG_INFO is not NULL then no |
| modules get added to DWFL, caller has to add them from filled in |
| R_DEBUG_INFO. |
| |
| For each link_map entry, if an existing module resides at its address, |
| this just modifies that module's name and suggested file name. If |
| no such module exists, this calls dwfl_report_elf on the l_name string. |
| |
| Returns the number of modules found, or -1 for errors. */ |
| |
| static int |
| report_r_debug (uint_fast8_t elfclass, uint_fast8_t elfdata, |
| Dwfl *dwfl, GElf_Addr r_debug_vaddr, |
| Dwfl_Memory_Callback *memory_callback, |
| void *memory_callback_arg, |
| struct r_debug_info *r_debug_info) |
| { |
| /* Skip r_version, to aligned r_map field. */ |
| GElf_Addr read_vaddr = r_debug_vaddr + addrsize (elfclass); |
| |
| void *buffer = NULL; |
| size_t buffer_available = 0; |
| GElf_Addr addrs[4]; |
| struct memory_closure memory_closure = { dwfl, memory_callback, |
| memory_callback_arg }; |
| if (unlikely (read_addrs (&memory_closure, elfclass, elfdata, |
| &buffer, &buffer_available, read_vaddr, &read_vaddr, |
| 1, addrs))) |
| return release_buffer (&memory_closure, &buffer, &buffer_available, -1); |
| |
| GElf_Addr next = addrs[0]; |
| |
| Dwfl_Module **lastmodp = &dwfl->modulelist; |
| int result = 0; |
| |
| /* There can't be more elements in the link_map list than there are |
| segments. DWFL->lookup_elts is probably twice that number, so it |
| is certainly above the upper bound. If we iterate too many times, |
| there must be a loop in the pointers due to link_map clobberation. */ |
| size_t iterations = 0; |
| while (next != 0 && ++iterations < dwfl->lookup_elts) |
| { |
| if (read_addrs (&memory_closure, elfclass, elfdata, |
| &buffer, &buffer_available, next, &read_vaddr, |
| 4, addrs)) |
| return release_buffer (&memory_closure, &buffer, &buffer_available, -1); |
| |
| /* Unused: l_addr is the difference between the address in memory |
| and the ELF file when the core was created. We need to |
| recalculate the difference below because the ELF file we use |
| might be differently pre-linked. */ |
| // GElf_Addr l_addr = addrs[0]; |
| GElf_Addr l_name = addrs[1]; |
| GElf_Addr l_ld = addrs[2]; |
| next = addrs[3]; |
| |
| /* If a clobbered or truncated memory image has no useful pointer, |
| just skip this element. */ |
| if (l_ld == 0) |
| continue; |
| |
| /* Fetch the string at the l_name address. */ |
| const char *name = NULL; |
| if (buffer != NULL |
| && read_vaddr <= l_name |
| && l_name + 1 - read_vaddr < buffer_available |
| && memchr (l_name - read_vaddr + buffer, '\0', |
| buffer_available - (l_name - read_vaddr)) != NULL) |
| name = l_name - read_vaddr + buffer; |
| else |
| { |
| release_buffer (&memory_closure, &buffer, &buffer_available, 0); |
| read_vaddr = l_name; |
| int segndx = INTUSE(dwfl_addrsegment) (dwfl, l_name, NULL); |
| if (likely (segndx >= 0) |
| && (*memory_callback) (dwfl, segndx, |
| &buffer, &buffer_available, |
| l_name, 0, memory_callback_arg)) |
| name = buffer; |
| } |
| |
| if (name != NULL && name[0] == '\0') |
| name = NULL; |
| |
| if (iterations == 1 |
| && dwfl->user_core != NULL |
| && dwfl->user_core->executable_for_core != NULL) |
| name = dwfl->user_core->executable_for_core; |
| |
| struct r_debug_info_module *r_debug_info_module = NULL; |
| if (r_debug_info != NULL) |
| { |
| /* Save link map information about valid shared library (or |
| executable) which has not been found on disk. */ |
| const char *name1 = name == NULL ? "" : name; |
| r_debug_info_module = malloc (sizeof (*r_debug_info_module) |
| + strlen (name1) + 1); |
| if (unlikely (r_debug_info_module == NULL)) |
| release_buffer (&memory_closure, &buffer, |
| &buffer_available, result); |
| r_debug_info_module->fd = -1; |
| r_debug_info_module->elf = NULL; |
| r_debug_info_module->l_ld = l_ld; |
| r_debug_info_module->start = 0; |
| r_debug_info_module->end = 0; |
| r_debug_info_module->disk_file_has_build_id = false; |
| strcpy (r_debug_info_module->name, name1); |
| r_debug_info_module->next = r_debug_info->module; |
| r_debug_info->module = r_debug_info_module; |
| } |
| |
| Dwfl_Module *mod = NULL; |
| if (name != NULL) |
| { |
| /* This code is mostly inlined dwfl_report_elf. */ |
| // XXX hook for sysroot |
| int fd = open (name, O_RDONLY); |
| if (fd >= 0) |
| { |
| Elf *elf; |
| Dwfl_Error error = __libdw_open_file (&fd, &elf, true, false); |
| GElf_Addr elf_dynamic_vaddr; |
| if (error == DWFL_E_NOERROR |
| && __libdwfl_dynamic_vaddr_get (elf, &elf_dynamic_vaddr)) |
| { |
| const void *build_id_bits; |
| GElf_Addr build_id_elfaddr; |
| int build_id_len; |
| bool valid = true; |
| |
| if (__libdwfl_find_elf_build_id (NULL, elf, &build_id_bits, |
| &build_id_elfaddr, |
| &build_id_len) > 0 |
| && build_id_elfaddr != 0) |
| { |
| if (r_debug_info_module != NULL) |
| r_debug_info_module->disk_file_has_build_id = true; |
| GElf_Addr build_id_vaddr = (build_id_elfaddr |
| - elf_dynamic_vaddr + l_ld); |
| |
| release_buffer (&memory_closure, &buffer, |
| &buffer_available, 0); |
| int segndx = INTUSE(dwfl_addrsegment) (dwfl, |
| build_id_vaddr, |
| NULL); |
| if (! (*memory_callback) (dwfl, segndx, |
| &buffer, &buffer_available, |
| build_id_vaddr, build_id_len, |
| memory_callback_arg)) |
| { |
| /* File has valid build-id which cannot be read from |
| memory. This happens for core files without bit 4 |
| (0x10) set in Linux /proc/PID/coredump_filter. */ |
| } |
| else |
| { |
| if (memcmp (build_id_bits, buffer, build_id_len) != 0) |
| /* File has valid build-id which does not match |
| the one in memory. */ |
| valid = false; |
| release_buffer (&memory_closure, &buffer, |
| &buffer_available, 0); |
| |
| } |
| } |
| |
| if (valid) |
| { |
| // It is like l_addr but it handles differently prelinked |
| // files at core dumping vs. core loading time. |
| GElf_Addr base = l_ld - elf_dynamic_vaddr; |
| if (r_debug_info_module == NULL) |
| { |
| // XXX hook for sysroot |
| mod = __libdwfl_report_elf (dwfl, basename (name), |
| name, fd, elf, base, |
| true, true); |
| if (mod != NULL) |
| { |
| elf = NULL; |
| fd = -1; |
| } |
| } |
| else if (__libdwfl_elf_address_range (elf, base, true, |
| true, NULL, NULL, |
| &r_debug_info_module->start, |
| &r_debug_info_module->end, |
| NULL, NULL)) |
| { |
| r_debug_info_module->elf = elf; |
| r_debug_info_module->fd = fd; |
| elf = NULL; |
| fd = -1; |
| } |
| } |
| if (elf != NULL) |
| elf_end (elf); |
| if (fd != -1) |
| close (fd); |
| } |
| } |
| } |
| |
| if (mod != NULL) |
| { |
| ++result; |
| |
| /* Move this module to the end of the list, so that we end |
| up with a list in the same order as the link_map chain. */ |
| if (mod->next != NULL) |
| { |
| if (*lastmodp != mod) |
| { |
| lastmodp = &dwfl->modulelist; |
| while (*lastmodp != mod) |
| lastmodp = &(*lastmodp)->next; |
| } |
| *lastmodp = mod->next; |
| mod->next = NULL; |
| while (*lastmodp != NULL) |
| lastmodp = &(*lastmodp)->next; |
| *lastmodp = mod; |
| } |
| |
| lastmodp = &mod->next; |
| } |
| } |
| |
| return release_buffer (&memory_closure, &buffer, &buffer_available, result); |
| } |
| |
| static GElf_Addr |
| consider_executable (Dwfl_Module *mod, GElf_Addr at_phdr, GElf_Addr at_entry, |
| uint_fast8_t *elfclass, uint_fast8_t *elfdata, |
| Dwfl_Memory_Callback *memory_callback, |
| void *memory_callback_arg) |
| { |
| GElf_Ehdr ehdr; |
| if (unlikely (gelf_getehdr (mod->main.elf, &ehdr) == NULL)) |
| return 0; |
| |
| if (at_entry != 0) |
| { |
| /* If we have an AT_ENTRY value, reject this executable if |
| its entry point address could not have supplied that. */ |
| |
| if (ehdr.e_entry == 0) |
| return 0; |
| |
| if (mod->e_type == ET_EXEC) |
| { |
| if (ehdr.e_entry != at_entry) |
| return 0; |
| } |
| else |
| { |
| /* It could be a PIE. */ |
| } |
| } |
| |
| // XXX this could be saved in the file cache: phdr vaddr, DT_DEBUG d_val vaddr |
| /* Find the vaddr of the DT_DEBUG's d_ptr. This is the memory |
| address where &r_debug was written at runtime. */ |
| GElf_Xword align = mod->dwfl->segment_align; |
| GElf_Addr d_val_vaddr = 0; |
| size_t phnum; |
| if (elf_getphdrnum (mod->main.elf, &phnum) != 0) |
| return 0; |
| |
| for (size_t i = 0; i < phnum; ++i) |
| { |
| GElf_Phdr phdr_mem; |
| GElf_Phdr *phdr = gelf_getphdr (mod->main.elf, i, &phdr_mem); |
| if (phdr == NULL) |
| break; |
| |
| if (phdr->p_align > 1 && (align == 0 || phdr->p_align < align)) |
| align = phdr->p_align; |
| |
| if (at_phdr != 0 |
| && phdr->p_type == PT_LOAD |
| && (phdr->p_offset & -align) == (ehdr.e_phoff & -align)) |
| { |
| /* This is the segment that would map the phdrs. |
| If we have an AT_PHDR value, reject this executable |
| if its phdr mapping could not have supplied that. */ |
| if (mod->e_type == ET_EXEC) |
| { |
| if (ehdr.e_phoff - phdr->p_offset + phdr->p_vaddr != at_phdr) |
| return 0; |
| } |
| else |
| { |
| /* It could be a PIE. If the AT_PHDR value and our |
| phdr address don't match modulo ALIGN, then this |
| could not have been the right PIE. */ |
| if (((ehdr.e_phoff - phdr->p_offset + phdr->p_vaddr) & -align) |
| != (at_phdr & -align)) |
| return 0; |
| |
| /* Calculate the bias applied to the PIE's p_vaddr values. */ |
| GElf_Addr bias = (at_phdr - (ehdr.e_phoff - phdr->p_offset |
| + phdr->p_vaddr)); |
| |
| /* Final sanity check: if we have an AT_ENTRY value, |
| reject this PIE unless its biased e_entry matches. */ |
| if (at_entry != 0 && at_entry != ehdr.e_entry + bias) |
| return 0; |
| |
| /* If we're changing the module's address range, |
| we've just invalidated the module lookup table. */ |
| GElf_Addr mod_bias = dwfl_adjusted_address (mod, 0); |
| if (bias != mod_bias) |
| { |
| mod->low_addr -= mod_bias; |
| mod->high_addr -= mod_bias; |
| mod->low_addr += bias; |
| mod->high_addr += bias; |
| |
| free (mod->dwfl->lookup_module); |
| mod->dwfl->lookup_module = NULL; |
| } |
| } |
| } |
| |
| if (phdr->p_type == PT_DYNAMIC) |
| { |
| Elf_Data *data = elf_getdata_rawchunk (mod->main.elf, phdr->p_offset, |
| phdr->p_filesz, ELF_T_DYN); |
| if (data == NULL) |
| continue; |
| const size_t entsize = gelf_fsize (mod->main.elf, |
| ELF_T_DYN, 1, EV_CURRENT); |
| const size_t n = data->d_size / entsize; |
| for (size_t j = 0; j < n; ++j) |
| { |
| GElf_Dyn dyn_mem; |
| GElf_Dyn *dyn = gelf_getdyn (data, j, &dyn_mem); |
| if (dyn != NULL && dyn->d_tag == DT_DEBUG) |
| { |
| d_val_vaddr = phdr->p_vaddr + entsize * j + entsize / 2; |
| break; |
| } |
| } |
| } |
| } |
| |
| if (d_val_vaddr != 0) |
| { |
| /* Now we have the final address from which to read &r_debug. */ |
| d_val_vaddr = dwfl_adjusted_address (mod, d_val_vaddr); |
| |
| void *buffer = NULL; |
| size_t buffer_available = addrsize (ehdr.e_ident[EI_CLASS]); |
| |
| int segndx = INTUSE(dwfl_addrsegment) (mod->dwfl, d_val_vaddr, NULL); |
| |
| if ((*memory_callback) (mod->dwfl, segndx, |
| &buffer, &buffer_available, |
| d_val_vaddr, buffer_available, |
| memory_callback_arg)) |
| { |
| const union |
| { |
| Elf32_Addr a32; |
| Elf64_Addr a64; |
| } *u = buffer; |
| |
| GElf_Addr vaddr; |
| if (ehdr.e_ident[EI_CLASS] == ELFCLASS32) |
| vaddr = (ehdr.e_ident[EI_DATA] == ELFDATA2MSB |
| ? BE32 (u->a32) : LE32 (u->a32)); |
| else |
| vaddr = (ehdr.e_ident[EI_DATA] == ELFDATA2MSB |
| ? BE64 (u->a64) : LE64 (u->a64)); |
| |
| (*memory_callback) (mod->dwfl, -1, &buffer, &buffer_available, 0, 0, |
| memory_callback_arg); |
| |
| if (*elfclass == ELFCLASSNONE) |
| *elfclass = ehdr.e_ident[EI_CLASS]; |
| else if (*elfclass != ehdr.e_ident[EI_CLASS]) |
| return 0; |
| |
| if (*elfdata == ELFDATANONE) |
| *elfdata = ehdr.e_ident[EI_DATA]; |
| else if (*elfdata != ehdr.e_ident[EI_DATA]) |
| return 0; |
| |
| return vaddr; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* Try to find an existing executable module with a DT_DEBUG. */ |
| static GElf_Addr |
| find_executable (Dwfl *dwfl, GElf_Addr at_phdr, GElf_Addr at_entry, |
| uint_fast8_t *elfclass, uint_fast8_t *elfdata, |
| Dwfl_Memory_Callback *memory_callback, |
| void *memory_callback_arg) |
| { |
| for (Dwfl_Module *mod = dwfl->modulelist; mod != NULL; mod = mod->next) |
| if (mod->main.elf != NULL) |
| { |
| GElf_Addr r_debug_vaddr = consider_executable (mod, at_phdr, at_entry, |
| elfclass, elfdata, |
| memory_callback, |
| memory_callback_arg); |
| if (r_debug_vaddr != 0) |
| return r_debug_vaddr; |
| } |
| |
| return 0; |
| } |
| |
| |
| int |
| dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size, |
| Dwfl_Memory_Callback *memory_callback, |
| void *memory_callback_arg, |
| struct r_debug_info *r_debug_info) |
| { |
| GElf_Addr r_debug_vaddr = 0; |
| |
| uint_fast8_t elfclass = ELFCLASSNONE; |
| uint_fast8_t elfdata = ELFDATANONE; |
| if (likely (auxv != NULL) |
| && likely (auxv_format_probe (auxv, auxv_size, &elfclass, &elfdata))) |
| { |
| GElf_Addr entry = 0; |
| GElf_Addr phdr = 0; |
| GElf_Xword phent = 0; |
| GElf_Xword phnum = 0; |
| |
| #define READ_AUXV32(ptr) read_4ubyte_unaligned_noncvt (ptr) |
| #define READ_AUXV64(ptr) read_8ubyte_unaligned_noncvt (ptr) |
| #define AUXV_SCAN(NN, BL) do \ |
| { \ |
| const Elf##NN##_auxv_t *av = auxv; \ |
| for (size_t i = 0; i < auxv_size / sizeof av[0]; ++i) \ |
| { \ |
| const char *typep = auxv + i * sizeof (Elf##NN##_auxv_t); \ |
| typep += offsetof (Elf##NN##_auxv_t, a_type); \ |
| uint##NN##_t type = READ_AUXV##NN (typep); \ |
| const char *valp = auxv + i * sizeof (Elf##NN##_auxv_t); \ |
| valp += offsetof (Elf##NN##_auxv_t, a_un.a_val); \ |
| uint##NN##_t val = BL##NN (READ_AUXV##NN (valp)); \ |
| if (type == BL##NN (AT_ENTRY)) \ |
| entry = val; \ |
| else if (type == BL##NN (AT_PHDR)) \ |
| phdr = val; \ |
| else if (type == BL##NN (AT_PHNUM)) \ |
| phnum = val; \ |
| else if (type == BL##NN (AT_PHENT)) \ |
| phent = val; \ |
| else if (type == BL##NN (AT_PAGESZ)) \ |
| { \ |
| if (val > 1 \ |
| && (dwfl->segment_align == 0 \ |
| || val < dwfl->segment_align)) \ |
| dwfl->segment_align = val; \ |
| } \ |
| } \ |
| } \ |
| while (0) |
| |
| if (elfclass == ELFCLASS32) |
| { |
| if (elfdata == ELFDATA2MSB) |
| AUXV_SCAN (32, BE); |
| else |
| AUXV_SCAN (32, LE); |
| } |
| else |
| { |
| if (elfdata == ELFDATA2MSB) |
| AUXV_SCAN (64, BE); |
| else |
| AUXV_SCAN (64, LE); |
| } |
| |
| /* If we found the phdr dimensions, search phdrs for PT_DYNAMIC. */ |
| GElf_Addr dyn_vaddr = 0; |
| GElf_Xword dyn_filesz = 0; |
| GElf_Addr dyn_bias = (GElf_Addr) -1; |
| |
| if (phdr != 0 && phnum != 0 |
| && ((elfclass == ELFCLASS32 && phent == sizeof (Elf32_Phdr)) |
| || (elfclass == ELFCLASS64 && phent == sizeof (Elf64_Phdr)))) |
| { |
| Dwfl_Module *phdr_mod; |
| int phdr_segndx = INTUSE(dwfl_addrsegment) (dwfl, phdr, &phdr_mod); |
| Elf_Data in = |
| { |
| .d_type = ELF_T_PHDR, |
| .d_version = EV_CURRENT, |
| .d_size = phnum * phent, |
| .d_buf = NULL |
| }; |
| bool in_ok = (*memory_callback) (dwfl, phdr_segndx, &in.d_buf, |
| &in.d_size, phdr, phnum * phent, |
| memory_callback_arg); |
| bool in_from_exec = false; |
| if (! in_ok |
| && dwfl->user_core != NULL |
| && dwfl->user_core->executable_for_core != NULL) |
| { |
| /* AUXV -> PHDR -> DYNAMIC |
| Both AUXV and DYNAMIC should be always present in a core file. |
| PHDR may be missing in core file, try to read it from |
| EXECUTABLE_FOR_CORE to find where DYNAMIC is located in the |
| core file. */ |
| |
| int fd = open (dwfl->user_core->executable_for_core, O_RDONLY); |
| Elf *elf; |
| Dwfl_Error error = DWFL_E_ERRNO; |
| if (fd != -1) |
| error = __libdw_open_file (&fd, &elf, true, false); |
| if (error != DWFL_E_NOERROR) |
| { |
| __libdwfl_seterrno (error); |
| return false; |
| } |
| GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem); |
| if (ehdr == NULL) |
| { |
| elf_end (elf); |
| close (fd); |
| __libdwfl_seterrno (DWFL_E_LIBELF); |
| return false; |
| } |
| size_t e_phnum; |
| if (elf_getphdrnum (elf, &e_phnum) != 0) |
| { |
| elf_end (elf); |
| close (fd); |
| __libdwfl_seterrno (DWFL_E_LIBELF); |
| return false; |
| } |
| if (e_phnum != phnum || ehdr->e_phentsize != phent) |
| { |
| elf_end (elf); |
| close (fd); |
| __libdwfl_seterrno (DWFL_E_BADELF); |
| return false; |
| } |
| off_t off = ehdr->e_phoff; |
| assert (in.d_buf == NULL); |
| /* Note this in the !in_ok path. That means memory_callback |
| failed. But the callback might still have reset the d_size |
| value (to zero). So explicitly set it here again. */ |
| if (unlikely (phnum > SIZE_MAX / phent)) |
| { |
| __libdwfl_seterrno (DWFL_E_NOMEM); |
| return false; |
| } |
| in.d_size = phnum * phent; |
| in.d_buf = malloc (in.d_size); |
| if (unlikely (in.d_buf == NULL)) |
| { |
| elf_end (elf); |
| close (fd); |
| __libdwfl_seterrno (DWFL_E_NOMEM); |
| return false; |
| } |
| ssize_t nread = pread_retry (fd, in.d_buf, in.d_size, off); |
| elf_end (elf); |
| close (fd); |
| if (nread != (ssize_t) in.d_size) |
| { |
| free (in.d_buf); |
| __libdwfl_seterrno (DWFL_E_ERRNO); |
| return false; |
| } |
| in_ok = true; |
| in_from_exec = true; |
| } |
| if (in_ok) |
| { |
| if (unlikely (phnum > SIZE_MAX / phent)) |
| { |
| __libdwfl_seterrno (DWFL_E_NOMEM); |
| return false; |
| } |
| size_t nbytes = phnum * phent; |
| /* We can only process as many bytes/phnum as there are |
| in in.d_size. The data might have been truncated. */ |
| if (nbytes > in.d_size) |
| { |
| nbytes = in.d_size; |
| phnum = nbytes / phent; |
| if (phnum == 0) |
| { |
| __libdwfl_seterrno (DWFL_E_BADELF); |
| return false; |
| } |
| } |
| void *buf = malloc (nbytes); |
| Elf32_Phdr (*p32)[phnum] = buf; |
| Elf64_Phdr (*p64)[phnum] = buf; |
| if (unlikely (buf == NULL)) |
| { |
| __libdwfl_seterrno (DWFL_E_NOMEM); |
| return false; |
| } |
| Elf_Data out = |
| { |
| .d_type = ELF_T_PHDR, |
| .d_version = EV_CURRENT, |
| .d_size = nbytes, |
| .d_buf = buf |
| }; |
| if (in.d_size > out.d_size) |
| { |
| in.d_size = out.d_size; |
| phnum = in.d_size / phent; |
| if (phnum == 0) |
| { |
| free (buf); |
| __libdwfl_seterrno (DWFL_E_BADELF); |
| return false; |
| } |
| } |
| bool is32 = (elfclass == ELFCLASS32); |
| size_t phdr_align = (is32 |
| ? __alignof__ (Elf32_Phdr) |
| : __alignof__ (Elf64_Phdr)); |
| if (!in_from_exec |
| && ((uintptr_t) in.d_buf & (phdr_align - 1)) != 0) |
| { |
| memcpy (out.d_buf, in.d_buf, in.d_size); |
| in.d_buf = out.d_buf; |
| } |
| if (likely ((elfclass == ELFCLASS32 |
| ? elf32_xlatetom : elf64_xlatetom) |
| (&out, &in, elfdata) != NULL)) |
| { |
| for (size_t i = 0; i < phnum; ++i) |
| { |
| GElf_Word type = (is32 |
| ? (*p32)[i].p_type |
| : (*p64)[i].p_type); |
| GElf_Addr vaddr = (is32 |
| ? (*p32)[i].p_vaddr |
| : (*p64)[i].p_vaddr); |
| GElf_Xword filesz = (is32 |
| ? (*p32)[i].p_filesz |
| : (*p64)[i].p_filesz); |
| |
| if (type == PT_PHDR) |
| { |
| if (dyn_bias == (GElf_Addr) -1 |
| /* Do a sanity check on the putative address. */ |
| && ((vaddr & (dwfl->segment_align - 1)) |
| == (phdr & (dwfl->segment_align - 1)))) |
| { |
| dyn_bias = phdr - vaddr; |
| if (dyn_vaddr != 0) |
| break; |
| } |
| |
| } |
| else if (type == PT_DYNAMIC) |
| { |
| dyn_vaddr = vaddr; |
| dyn_filesz = filesz; |
| if (dyn_bias != (GElf_Addr) -1) |
| break; |
| } |
| } |
| } |
| |
| if (in_from_exec) |
| free (in.d_buf); |
| else |
| (*memory_callback) (dwfl, -1, &in.d_buf, &in.d_size, 0, 0, |
| memory_callback_arg); |
| free (buf); |
| } |
| else |
| /* We could not read the executable's phdrs from the |
| memory image. If we have a presupplied executable, |
| we can still use the AT_PHDR and AT_ENTRY values to |
| verify it, and to adjust its bias if it's a PIE. |
| |
| If there was an ET_EXEC module presupplied that contains |
| the AT_PHDR address, then we only consider that one. |
| We'll either accept it if its phdr location and e_entry |
| make sense or reject it if they don't. If there is no |
| presupplied ET_EXEC, then look for a presupplied module, |
| which might be a PIE (ET_DYN) that needs its bias adjusted. */ |
| r_debug_vaddr = ((phdr_mod == NULL |
| || phdr_mod->main.elf == NULL |
| || phdr_mod->e_type != ET_EXEC) |
| ? find_executable (dwfl, phdr, entry, |
| &elfclass, &elfdata, |
| memory_callback, |
| memory_callback_arg) |
| : consider_executable (phdr_mod, phdr, entry, |
| &elfclass, &elfdata, |
| memory_callback, |
| memory_callback_arg)); |
| } |
| |
| /* If we found PT_DYNAMIC, search it for DT_DEBUG. */ |
| if (dyn_filesz != 0) |
| { |
| if (dyn_bias != (GElf_Addr) -1) |
| dyn_vaddr += dyn_bias; |
| |
| Elf_Data in = |
| { |
| .d_type = ELF_T_DYN, |
| .d_version = EV_CURRENT, |
| .d_size = dyn_filesz, |
| .d_buf = NULL |
| }; |
| int dyn_segndx = dwfl_addrsegment (dwfl, dyn_vaddr, NULL); |
| if ((*memory_callback) (dwfl, dyn_segndx, &in.d_buf, &in.d_size, |
| dyn_vaddr, dyn_filesz, memory_callback_arg)) |
| { |
| size_t entsize = (elfclass == ELFCLASS32 |
| ? sizeof (Elf32_Dyn) : sizeof (Elf64_Dyn)); |
| if (unlikely (dyn_filesz > SIZE_MAX / entsize)) |
| { |
| __libdwfl_seterrno (DWFL_E_NOMEM); |
| return false; |
| } |
| /* We can only process as many bytes as there are in |
| in.d_size. The data might have been truncated. */ |
| if (dyn_filesz > in.d_size) |
| dyn_filesz = in.d_size; |
| if (dyn_filesz / entsize == 0) |
| { |
| __libdwfl_seterrno (DWFL_E_BADELF); |
| return false; |
| } |
| void *buf = malloc (dyn_filesz); |
| if (unlikely (buf == NULL)) |
| { |
| __libdwfl_seterrno (DWFL_E_NOMEM); |
| return false; |
| } |
| Elf_Data out = |
| { |
| .d_type = ELF_T_DYN, |
| .d_version = EV_CURRENT, |
| .d_size = dyn_filesz, |
| .d_buf = buf |
| }; |
| if (in.d_size > out.d_size) |
| in.d_size = out.d_size; |
| size_t dyn_align = (elfclass == ELFCLASS32 |
| ? __alignof__ (Elf32_Dyn) |
| : __alignof__ (Elf64_Dyn)); |
| if (((uintptr_t) in.d_buf & (dyn_align - 1)) != 0) |
| { |
| memcpy (out.d_buf, in.d_buf, in.d_size); |
| in.d_buf = out.d_buf; |
| } |
| if (likely ((elfclass == ELFCLASS32 |
| ? elf32_xlatetom : elf64_xlatetom) |
| (&out, &in, elfdata) != NULL)) |
| { |
| /* We are looking for DT_DEBUG. */ |
| if (elfclass == ELFCLASS32) |
| { |
| Elf32_Dyn (*d32)[dyn_filesz / sizeof (Elf32_Dyn)] = buf; |
| size_t n = dyn_filesz / sizeof (Elf32_Dyn); |
| for (size_t i = 0; i < n; ++i) |
| if ((*d32)[i].d_tag == DT_DEBUG) |
| { |
| r_debug_vaddr = (*d32)[i].d_un.d_val; |
| break; |
| } |
| } |
| else |
| { |
| Elf64_Dyn (*d64)[dyn_filesz / sizeof (Elf64_Dyn)] = buf; |
| size_t n = dyn_filesz / sizeof (Elf64_Dyn); |
| for (size_t i = 0; i < n; ++i) |
| if ((*d64)[i].d_tag == DT_DEBUG) |
| { |
| r_debug_vaddr = (*d64)[i].d_un.d_val; |
| break; |
| } |
| } |
| } |
| |
| (*memory_callback) (dwfl, -1, &in.d_buf, &in.d_size, 0, 0, |
| memory_callback_arg); |
| free (buf); |
| } |
| } |
| } |
| else |
| /* We have to look for a presupplied executable file to determine |
| the vaddr of its dynamic section and DT_DEBUG therein. */ |
| r_debug_vaddr = find_executable (dwfl, 0, 0, &elfclass, &elfdata, |
| memory_callback, memory_callback_arg); |
| |
| if (r_debug_vaddr == 0) |
| return 0; |
| |
| /* For following pointers from struct link_map, we will use an |
| integrated memory access callback that can consult module text |
| elided from the core file. This is necessary when the l_name |
| pointer for the dynamic linker's own entry is a pointer into the |
| executable's .interp section. */ |
| struct integrated_memory_callback mcb = |
| { |
| .memory_callback = memory_callback, |
| .memory_callback_arg = memory_callback_arg |
| }; |
| |
| /* Now we can follow the dynamic linker's library list. */ |
| return report_r_debug (elfclass, elfdata, dwfl, r_debug_vaddr, |
| &integrated_memory_callback, &mcb, r_debug_info); |
| } |
| INTDEF (dwfl_link_map_report) |
