static Dwarf_CFI *
allocate_cfi (Elf *elf, GElf_Addr vaddr)
{
Dwarf_CFI *cfi = calloc (1, sizeof *cfi);
if (cfi == NULL)
{
__libdw_seterrno (DWARF_E_NOMEM);
return NULL;
}
cfi->e_ident = (unsigned char *) elf_getident (elf, NULL);
if (cfi->e_ident == NULL)
{
free (cfi);
__libdw_seterrno (DWARF_E_GETEHDR_ERROR);
return NULL;
}
if ((BYTE_ORDER == LITTLE_ENDIAN && cfi->e_ident[EI_DATA] == ELFDATA2MSB)
|| (BYTE_ORDER == BIG_ENDIAN && cfi->e_ident[EI_DATA] == ELFDATA2LSB))
cfi->other_byte_order = true;
cfi->frame_vaddr = vaddr;
cfi->textrel = 0; /* XXX ? */
cfi->datarel = 0; /* XXX ? */
return cfi;
}
static void
get_elf_pointer_size(Dwarf *dw)
{
Elf *elf;
char *elf_ident;
size_t elf_nident;
elf = dwarf_getelf(dw);
elf_ident = elf_getident(elf, &elf_nident);
assert(elf_ident != NULL && elf_nident > EI_CLASS);
switch ((uint8_t)elf_ident[EI_CLASS]) {
case ELFCLASS32:
pointer_size = 4;
break;
case ELFCLASS64:
pointer_size = 8;
break;
case ELFCLASSNONE:
default:
errx(EX_DATAERR, "Bogus ELF ident header, machine class=%u.\n",
(unsigned)elf_ident[EI_CLASS]);
}
}
void print_relocinfo (Dwarf_Debug dbg)
{
Elf *elf;
char *endr_ident;
int is_64bit;
int res;
int i;
for (i = 0; i < DW_SECTION_REL_DEBUG_NUM; i ++) {
sect_data[i].buf = 0;
sect_data[i].size = 0;
}
res = dwarf_get_elf(dbg,&elf, &err);
if(res != DW_DLV_OK) {
print_error(dbg, "dwarf_get_elf error",res, err);
}
if ((endr_ident = elf_getident(elf, NULL)) == NULL) {
print_error(dbg, "DW_ELF_GETIDENT_ERROR",res, err);
}
is_64bit = (endr_ident[EI_CLASS] == ELFCLASS64);
if (is_64bit) {
print_relocinfo_64(dbg, elf);
}
else {
print_relocinfo_32(dbg, elf);
}
}
/*
* get_elf_class - get the target executable elf class
* i.e. ELFCLASS64 or ELFCLASS32.
*/
static int
get_elf_class(char *filename)
{
int elfclass = -1;
int elffd = get_executable(filename);
Elf *elf;
size_t size;
char *ident;
GElf_Ehdr ehdr;
if (elffd < 0)
return (elfclass);
if (elf_version(EV_CURRENT) == EV_NONE) {
(void) close(elffd);
return (elfclass);
}
elf = elf_begin(elffd, ELF_C_READ, (Elf *) 0);
/*
* verify information in file header
*/
if (gelf_getehdr(elf, &ehdr) == (GElf_Ehdr *) 0) {
close(elffd);
return (elfclass);
}
ident = elf_getident(elf, &size);
if (ident[EI_CLASS] == ELFCLASS32)
elfclass = ELFCLASS32;
if (ident[EI_CLASS] == ELFCLASS64)
elfclass = ELFCLASS64;
close(elffd);
return (elfclass);
}
Dwarf_CFI *
dwarf_getcfi (Dwarf *dbg)
{
if (dbg == NULL)
return NULL;
if (dbg->cfi == NULL && dbg->sectiondata[IDX_debug_frame] != NULL)
{
Dwarf_CFI *cfi = libdw_typed_alloc (dbg, Dwarf_CFI);
cfi->dbg = dbg;
cfi->data = (Elf_Data_Scn *) dbg->sectiondata[IDX_debug_frame];
cfi->search_table = NULL;
cfi->search_table_vaddr = 0;
cfi->search_table_entries = 0;
cfi->search_table_encoding = DW_EH_PE_omit;
cfi->frame_vaddr = 0;
cfi->textrel = 0;
cfi->datarel = 0;
cfi->e_ident = (unsigned char *) elf_getident (dbg->elf, NULL);
cfi->other_byte_order = dbg->other_byte_order;
cfi->next_offset = 0;
cfi->cie_tree = cfi->fde_tree = cfi->expr_tree = NULL;
cfi->ebl = NULL;
dbg->cfi = cfi;
}
return dbg->cfi;
}
uint8_t *load_elf_file(char *elf_file_name, int *size)
{
uint8_t *buf = NULL;
char *id;
if (elf_version(EV_CURRENT) == EV_NONE)
return NULL;
int fd = open(elf_file_name, O_RDONLY , 0);
if (fd < 0) {
printf("Can't open %s\n", elf_file_name);
return NULL;
}
Elf *elf_object = elf_begin(fd , ELF_C_READ , NULL);
if (elf_object == NULL) {
printf("Problem while starting ELF parsing\n");
close(fd);
return NULL;
}
if (elf_kind(elf_object) != ELF_K_ELF) {
printf("%s is not an ELF file\n", elf_file_name);
elf_end(elf_object);
close(fd);
return NULL;
}
if (( id = elf_getident (elf_object , NULL )) == NULL )
printf("getident() failed : %s.",
elf_errmsg(-1));
if (id[EI_DATA] == ELFDATA2LSB)
big_endian = 0;
else if (id[EI_DATA] == ELFDATA2MSB)
big_endian = 1;
else {
printf("%s has unknown endianness '%d'\n", elf_file_name, id[EI_DATA]);
elf_end(elf_object);
close(fd);
return NULL;
}
buf = dump_program_data(elf_object, size);
if (buf == NULL)
buf = dump_section_data(elf_object, size);
elf_end(elf_object);
close(fd);
return buf;
}
static int read_ehdr(struct elf32_info *info, FILE *in)
{
/* Read and check the ELF header */
char *id;
rewind(in);
if (elf_version(EV_CURRENT) == EV_NONE) {
printc_err("elf32: elf_version failed");
return -1;
}
/* ELF_C_READ_MMAP* is not available in Mac OS X macports libelf @0.8.10_1 */
info->elf = elf_begin(fileno(in), ELF_C_READ, NULL);
if (info->elf == 0) {
printc_err("elf32: elf_begin failed");
return -1;
}
if (elf_kind(info->elf) != ELF_K_ELF) {
printc_err("elf32: elf_kind is not ELF_K_ELF");
return -1;
}
if (gelf_getehdr(info->elf, &info->file_ehdr) == 0) {
printc_err("elf32: couldn't get ELF header");
return -1;
}
if ((id = elf_getident(info->elf, NULL)) == 0) {
printc_err("elf32: couldn't getident");
return -1;
}
if (memcmp(id, elf32_id, sizeof(elf32_id))) {
printc_err("elf32: not an ELF32 file\n");
return -1;
}
return 0;
}
const char *
ebl_symbol_binding_name (Ebl *ebl, int binding, char *buf, size_t len)
{
const char *res;
res = ebl != NULL ? ebl->symbol_type_name (binding, buf, len) : NULL;
if (res == NULL)
{
static const char *stb_names[STB_NUM] =
{
"LOCAL", "GLOBAL", "WEAK"
};
/* Standard binding? */
if (binding < STB_NUM)
res = stb_names[binding];
else
{
char *ident;
if (binding >= STB_LOPROC && binding <= STB_HIPROC)
snprintf (buf, len, "LOPROC+%d", binding - STB_LOPROC);
else if (binding == STB_GNU_UNIQUE
&& (ident = elf_getident (ebl->elf, NULL)) != NULL
&& ident[EI_OSABI] == ELFOSABI_LINUX)
return "GNU_UNIQUE";
else if (binding >= STB_LOOS && binding <= STB_HIOS)
snprintf (buf, len, "LOOS+%d", binding - STB_LOOS);
else
snprintf (buf, len, gettext ("<unknown>: %d"), binding);
res = buf;
}
}
return res;
}
int
xlate_named_init_elf(Elf * elf, const char *section_name,
xlate_table_con * ret_tab_ptr)
{
int retstatus = XLATE_TB_STATUS_NO_ERROR;
xlate_table_con newtab = 0;
Elf_Scn *scn = 0;
int is64bit = 0;
char *ident;
size_t identsize;
Elf_Scn *xlscn = 0;
Elf64_Shdr *shdr64 = 0;
Elf32_Shdr *shdr32 = 0;
Elf32_Ehdr *ehdr32 = 0;
Elf64_Ehdr *ehdr64 = 0;
Elf_Data *xlatedata = 0;
int stringindex = 0;
char * sec_name;
if(elf_kind(elf) != ELF_K_ELF) {
return XLATE_TB_STATUS_NOT_ELF;
}
ident = elf_getident(elf,&identsize);
if(ident == 0 || identsize < EI_NIDENT) {
return XLATE_TB_STATUS_ELF_IDENT_BAD;
}
if(ident[EI_CLASS] == ELFCLASS64) {
is64bit = 1;
}
if(is64bit) {
ehdr64 = elf64_getehdr(elf);
if(ehdr64 == 0 ) {
return XLATE_TB_STATUS_ELF_EHDR_BAD;
}
stringindex = ehdr64->e_shstrndx;
} else {
ehdr32 = elf32_getehdr(elf);
if(ehdr32 == 0 ) {
return XLATE_TB_STATUS_ELF_EHDR_BAD;
}
stringindex = ehdr32->e_shstrndx;
}
for(scn = elf_nextscn(elf,scn);
scn != 0 && xlscn == 0
; scn = elf_nextscn(elf,scn)) {
if(is64bit) {
shdr64 = elf64_getshdr(scn);
if(shdr64 == 0) {
return XLATE_TB_STATUS_ELF_SHDR_BAD;
}
sec_name = elf_strptr(elf,stringindex,shdr64->sh_name);
if(sec_name == 0) {
return XLATE_TB_STATUS_ELF_STRPTR_BAD;
}
if(shdr64->sh_type != SHT_MIPS_XLATE &&
shdr64->sh_type != SHT_MIPS_XLATE_DEBUG &&
shdr64->sh_type != SHT_MIPS_XLATE_OLD ) {
continue;
}
if(!streq(section_name,sec_name)) {
continue;
}
xlscn = scn;
break;
} else {
shdr32 = elf32_getshdr(scn);
if(shdr32 == 0) {
return XLATE_TB_STATUS_ELF_SHDR_BAD;
}
sec_name = elf_strptr(elf,stringindex,shdr32->sh_name);
if(sec_name == 0) {
return XLATE_TB_STATUS_ELF_STRPTR_BAD;
}
if(shdr32->sh_type != SHT_MIPS_XLATE &&
shdr32->sh_type != SHT_MIPS_XLATE_DEBUG &&
shdr32->sh_type != SHT_MIPS_XLATE_OLD ) {
continue;
}
if(!streq(section_name,sec_name)) {
continue;
}
xlscn = scn;
break;
}
}
if(xlscn == 0) {
return XLATE_TB_STATUS_NO_XLATE;
}
xlatedata = elf_getdata(xlscn,NULL);
if(xlatedata == NULL || xlatedata->d_size == 0) {
return XLATE_TB_STATUS_NO_XLATE_DATA;
}
newtab = (xlate_table_con)malloc(sizeof(struct xlate_table_con_s));
if(newtab == NULL) {
return XLATE_TB_STATUS_ALLOC_FAIL;
}
bzero(newtab,sizeof(struct xlate_table_con_s));
newtab->xc_elf = elf;
newtab->xc_section_data = xlatedata->d_buf;
newtab->xc_data_size = xlatedata->d_size;
if(newtab->xc_data_size != xlatedata->d_size) {
/* we have a gigantic section and are compiled only 32 bit.
** we simply cannot handle and I don't think the
** mmap would have worked anyway so we cannot really
** get here.
*/
free(newtab);
return XLATE_TB_STATUS_SECTION_TOO_BIG;
}
retstatus = _xlate_fill_in_table_data(newtab,is64bit);
if(retstatus != XLATE_TB_STATUS_NO_ERROR) {
free(newtab);
return retstatus;
}
newtab->xc_valid_table = VALID_TABLE_MAGIC;
*ret_tab_ptr = newtab;
return retstatus;
}
/* dwarf_elf_object_access_internals_init() */
static int
dwarf_elf_object_access_internals_init(void* obj_in,
dwarf_elf_handle elf,
int* error)
{
dwarf_elf_object_access_internals_t*obj =
(dwarf_elf_object_access_internals_t*)obj_in;
char *ehdr_ident = 0;
Dwarf_Half machine = 0;
obj->elf = elf;
if ((ehdr_ident = elf_getident(elf, NULL)) == NULL) {
*error = DW_DLE_ELF_GETIDENT_ERROR;
return DW_DLV_ERROR;
}
obj->is_64bit = (ehdr_ident[EI_CLASS] == ELFCLASS64);
if (ehdr_ident[EI_DATA] == ELFDATA2LSB){
obj->endianness = DW_OBJECT_LSB;
} else if (ehdr_ident[EI_DATA] == ELFDATA2MSB){
obj->endianness = DW_OBJECT_MSB;
}
if (obj->is_64bit) {
#ifdef HAVE_ELF64_GETEHDR
obj->ehdr64 = elf64_getehdr(elf);
if (obj->ehdr64 == NULL) {
*error = DW_DLE_ELF_GETEHDR_ERROR;
return DW_DLV_ERROR;
}
obj->section_count = obj->ehdr64->e_shnum;
machine = obj->ehdr64->e_machine;
obj->machine = machine;
#else
*error = DW_DLE_NO_ELF64_SUPPORT;
return DW_DLV_ERROR;
#endif
} else {
obj->ehdr32 = elf32_getehdr(elf);
if (obj->ehdr32 == NULL) {
*error = DW_DLE_ELF_GETEHDR_ERROR;
return DW_DLV_ERROR;
}
obj->section_count = obj->ehdr32->e_shnum;
machine = obj->ehdr32->e_machine;
obj->machine = machine;
}
/* The following length_size is Not Too Significant. Only used
one calculation, and an approximate one at that. */
obj->length_size = obj->is_64bit ? 8 : 4;
obj->pointer_size = obj->is_64bit ? 8 : 4;
if (obj->is_64bit && machine != EM_MIPS) {
/* MIPS/IRIX makes pointer size and length size 8 for -64.
Other platforms make length 4 always. */
/* 4 here supports 32bit-offset dwarf2, as emitted by cygnus
tools, and the dwarfv2.1 64bit extension setting.
This is not the same as the size-of-an-offset, which
is 4 in 32bit dwarf and 8 in 64bit dwarf. */
obj->length_size = 4;
}
return DW_DLV_OK;
}
/* Load ELF 'filename', parse the .eh_frame contents, and for each entry in the
* second argument check whether its address is contained in the range of some
* Frame Description Entry. If it does, fill in the function range of the
* entry. In other words, try to assign start address and length of function
* corresponding to each backtrace entry. We'll need that for the disassembly.
*
* Fails quietly - we should still be able to use the build ids.
*
* I wonder if this is really better than parsing eu-readelf text output.
*/
static GHashTable *elf_iterate_fdes(const char *filename, GList *entries, Elf *e)
{
const unsigned char *e_ident;
Elf_Data *scn_data;
GElf_Shdr shdr;
GElf_Phdr phdr;
size_t phnum;
GHashTable *retval = NULL; /* NULL = error */
e_ident = (unsigned char *)elf_getident(e, NULL);
if (e_ident == NULL)
{
VERB1 log_elf_error("elf_getident", filename);
return NULL;
}
/* Look up the .eh_frame section */
if (!xelf_section_by_name(e, ".eh_frame", filename, &scn_data, &shdr))
{
VERB1 log("Section .eh_frame not found in %s", filename);
return NULL;
}
/* Get the address at which the executable segment is loaded. If the
* .eh_frame addresses are absolute, this is used to convert them to
* relative to the beginning of executable segment. We are looking for the
* first LOAD segment that is executable, I hope this is sufficient.
*/
if (elf_getphdrnum(e, &phnum) != 0)
{
VERB1 log_elf_error("elf_getphdrnum", filename);
return NULL;
}
uintptr_t exec_base;
int i;
for (i = 0; i < phnum; i++)
{
if (gelf_getphdr(e, i, &phdr) != &phdr)
{
VERB1 log_elf_error("gelf_getphdr", filename);
return NULL;
}
if (phdr.p_type == PT_LOAD && phdr.p_flags & PF_X)
{
exec_base = (uintptr_t)phdr.p_vaddr;
goto base_found;
}
}
VERB1 log("Can't determine executable base for '%s'", filename);
return NULL;
base_found:
VERB2 log("Executable base: %jx", (uintmax_t)exec_base);
/* We now have a handle to .eh_frame data. We'll use dwarf_next_cfi to
* iterate through all FDEs looking for those matching the addresses we
* have.
* Some info on .eh_frame can be found at http://www.airs.com/blog/archives/460
* and in DWARF documentation for .debug_frame. The initial_location and
* address_range decoding is 'inspired' by elfutils source.
* XXX: If this linear scan is too slow, we can do binary search on
* .eh_frame_hdr -- see http://www.airs.com/blog/archives/462
*/
int ret;
Dwarf_Off cfi_offset;
Dwarf_Off cfi_offset_next = 0;
Dwarf_CFI_Entry cfi;
struct cie_encoding {
Dwarf_Off cie_offset;
int ptr_len;
bool pcrel;
} *cie;
GList *cie_list = NULL;
/* Init hash table
* keys are pointers to integers which we allocate with malloc
* values stored directly */
GHashTable *hash = g_hash_table_new_full(g_int64_hash, g_int64_equal, free, NULL);
while(1)
{
cfi_offset = cfi_offset_next;
ret = dwarf_next_cfi(e_ident, scn_data, 1, cfi_offset, &cfi_offset_next, &cfi);
if (ret > 0)
{
/* We're at the end. */
break;
}
if (ret < 0)
{
/* Error. If cfi_offset_next was updated, we may skip the
* erroneous cfi. */
if (cfi_offset_next > cfi_offset)
{
continue;
}
VERB1 log("dwarf_next_cfi failed for %s: %s", filename, dwarf_errmsg(-1));
goto ret_free;
}
if (dwarf_cfi_cie_p(&cfi))
{
/* Current CFI is a CIE. We store its offset and FDE encoding
* attributes to be used when reading FDEs.
*/
/* Default FDE encoding (i.e. no R in augmentation string) is
* DW_EH_PE_absptr.
*/
cie = btp_mallocz(sizeof(*cie));
cie->cie_offset = cfi_offset;
cie->ptr_len = encoded_size(DW_EH_PE_absptr, e_ident);
/* Search the augmentation data for FDE pointer encoding.
* Unfortunately, 'P' can come before 'R' (which we are looking
* for), so we may have to parse the whole thing. See the
* abovementioned blog post for details.
*/
const char *aug = cfi.cie.augmentation;
const uint8_t *augdata = cfi.cie.augmentation_data;
bool skip_cie = 0;
if (*aug == 'z')
{
aug++;
}
while (*aug != '\0')
{
if(*aug == 'R')
{
cie->ptr_len = encoded_size(*augdata, e_ident);
if (cie->ptr_len != 4 && cie->ptr_len != 8)
{
VERB1 log("Unknown FDE encoding (CIE %jx) in %s",
(uintmax_t)cfi_offset, filename);
skip_cie = 1;
}
if ((*augdata & 0x70) == DW_EH_PE_pcrel)
{
cie->pcrel = 1;
}
break;
}
else if (*aug == 'L')
{
augdata++;
}
else if (*aug == 'P')
{
unsigned size = encoded_size(*augdata, e_ident);
if (size == 0)
{
VERB1 log("Unknown size for personality encoding in %s",
filename);
skip_cie = 1;
break;
}
augdata += (size + 1);
}
else
{
VERB1 log("Unknown augmentation char in %s", filename);
skip_cie = 1;
break;
}
aug++;
}
if (skip_cie)
{
free(cie);
continue;
}
cie_list = g_list_append(cie_list, cie);
}
else
{
/* Current CFI is an FDE.
*/
GList *it = cie_list;
cie = NULL;
/* Find the CIE data that we should have saved earlier. XXX: We can
* use hash table/tree to speed up the search, the number of CIEs
* should usally be very low though. */
while (it != NULL)
{
cie = it->data;
/* In .eh_frame, CIE_pointer is relative, but libdw converts it
* to absolute offset. */
if(cfi.fde.CIE_pointer == cie->cie_offset)
{
break; /* Found. */
}
it = g_list_next(it);
}
if (it == NULL)
{
VERB1 log("CIE not found for FDE %jx in %s",
(uintmax_t)cfi_offset, filename);
continue;
}
/* Read the two numbers we need and if they are PC-relative,
* compute the offset from VMA base
*/
uintptr_t initial_location = fde_read_address(cfi.fde.start, cie->ptr_len);
uintptr_t address_range = fde_read_address(cfi.fde.start+cie->ptr_len, cie->ptr_len);
if (cie->pcrel)
{
/* We need to determine how long is the 'length' (and
* consequently CIE id) field of this FDE -- it can be either 4
* or 12 bytes long. */
uintptr_t length = fde_read_address(scn_data->d_buf + cfi_offset, 4);
uintptr_t skip = (length == 0xffffffffUL ? 12 : 4);
uintptr_t mask = (cie->ptr_len == 4 ? 0xffffffffUL : 0xffffffffffffffffUL);
initial_location += (uintptr_t)shdr.sh_offset + (uintptr_t)cfi_offset + 2*skip;
initial_location &= mask;
}
else
{
/* Assuming that not pcrel means absolute address (what if the file is a library?).
* Convert to text-section-start-relative.
*/
initial_location -= exec_base;
}
/* Insert the pair into hash */
uintptr_t *key = addr_alloc(initial_location + exec_base);
g_hash_table_insert(hash, key, (gpointer)address_range);
VERB3 log("FDE start: 0x%jx length: %u", (uintmax_t)*key, (unsigned)address_range);
/* Iterate through the backtrace entries and check each address
* member whether it belongs into the range given by current FDE.
*/
for (it = entries; it != NULL; it = g_list_next(it))
{
struct backtrace_entry *entry = it->data;
if (initial_location <= entry->build_id_offset
&& entry->build_id_offset < initial_location + address_range)
{
/* Convert to before-relocation absolute addresses, disassembler uses those. */
entry->function_initial_loc = exec_base + initial_location;
entry->function_length = address_range;
/*TODO: remove the entry from the list to save a bit of time in next iteration?*/
}
}
}
}
retval = hash; /* success */
ret_free:
list_free_with_free(cie_list);
if (retval == NULL)
g_hash_table_destroy(hash);
return retval;
}
int
xlate_init_elf(Elf * elf, int open_debug_table,
xlate_table_con * ret_tab_ptr)
{
int res;
Elf32_Word wanttype;
Elf_Scn *scn = 0;
int is64bit = 0;
char *ident;
size_t identsize;
Elf64_Shdr *shdr64 = 0;
Elf32_Shdr *shdr32 = 0;
Elf32_Ehdr *ehdr32 = 0;
Elf64_Ehdr *ehdr64 = 0;
int stringindex = 0;
char * sec_name;
if(elf_kind(elf) != ELF_K_ELF) {
return XLATE_TB_STATUS_NOT_ELF;
}
ident = elf_getident(elf,&identsize);
if(open_debug_table == XLATE_OPEN_STD_TABLE) {
/* we take the first SHT_MIPS_XLATE*/
wanttype = SHT_MIPS_XLATE;
} else if(open_debug_table == XLATE_OPEN_DEBUG_TABLE) {
/* we take the first SHT_MIPS_XLATE_DEBUG */
wanttype = SHT_MIPS_XLATE_DEBUG;
} else {
return XLATE_TB_STATUS_NO_XLATE;
}
res = XLATE_TB_STATUS_NO_XLATE;
if(ident == 0 || identsize < EI_NIDENT) {
return XLATE_TB_STATUS_ELF_IDENT_BAD;
}
if(ident[EI_CLASS] == ELFCLASS64) {
is64bit = 1;
}
if(is64bit) {
ehdr64 = elf64_getehdr(elf);
if(ehdr64 == 0 ) {
return XLATE_TB_STATUS_ELF_EHDR_BAD;
}
stringindex = ehdr64->e_shstrndx;
} else {
ehdr32 = elf32_getehdr(elf);
if(ehdr32 == 0 ) {
return XLATE_TB_STATUS_ELF_EHDR_BAD;
}
stringindex = ehdr32->e_shstrndx;
}
for(scn = elf_nextscn(elf,scn);
scn != 0
; scn = elf_nextscn(elf,scn)) {
if(is64bit) {
shdr64 = elf64_getshdr(scn);
if(shdr64 == 0) {
return XLATE_TB_STATUS_ELF_SHDR_BAD;
}
sec_name = elf_strptr(elf,stringindex,shdr64->sh_name);
if(sec_name == 0) {
return XLATE_TB_STATUS_ELF_STRPTR_BAD;
}
if(shdr64->sh_type != wanttype) {
continue;
}
res = xlate_named_init_elf(elf,
sec_name,ret_tab_ptr);
return res;
} else {
shdr32 = elf32_getshdr(scn);
if(shdr32 == 0) {
return XLATE_TB_STATUS_ELF_SHDR_BAD;
}
sec_name = elf_strptr(elf,stringindex,shdr32->sh_name);
if(sec_name == 0) {
return XLATE_TB_STATUS_ELF_STRPTR_BAD;
}
if(shdr32->sh_type != wanttype) {
continue;
}
res = xlate_named_init_elf(elf,
sec_name,ret_tab_ptr);
return res;
}
}
return res;
}
/*
Given an Elf ptr, set up dbg with pointers
to all the Dwarf data sections.
Return NULL on error.
This function is also responsible for determining
whether the given object contains Dwarf information
or not. The test currently used is that it contains
either a .debug_info or a .debug_frame section. If
not, it returns DW_DLV_NO_ENTRY causing dwarf_init() also to
return DW_DLV_NO_ENTRY. Earlier, we had thought of using only
the presence/absence of .debug_info to test, but we
added .debug_frame since there could be stripped objects
that have only a .debug_frame section for exception
processing.
DW_DLV_NO_ENTRY or DW_DLV_OK or DW_DLV_ERROR
*/
static int
_dwarf_setup(Dwarf_Debug dbg, dwarf_elf_handle elf, Dwarf_Error * error)
{
#ifdef __SGI_FAST_LIBELF
Elf64_Ehdr ehdr;
Elf64_Shdr shdr;
enum elf_sgi_error_type sres;
unsigned char const* ehdr_ident;
#else
Elf32_Ehdr *ehdr32;
#ifdef HAVE_ELF64_GETEHDR
Elf64_Ehdr *ehdr64;
#endif
Elf32_Shdr *shdr32;
#ifdef HAVE_ELF64_GETSHDR
Elf64_Shdr *shdr64;
#endif
Elf_Scn *scn;
char *ehdr_ident;
#endif /* !defined(__SGI_FAST_LIBELF) */
Dwarf_Half machine;
char *scn_name;
int is_64bit;
int foundDwarf;
Dwarf_Unsigned section_size;
Dwarf_Unsigned section_count;
Dwarf_Half section_index;
foundDwarf = FALSE;
dbg->de_elf = elf;
dbg->de_assume_string_in_bounds = _dwarf_assume_string_bad;
#ifdef __SGI_FAST_LIBELF
sres = elf_sgi_ehdr(elf, &ehdr);
if (sres != ELF_SGI_ERROR_OK) {
DWARF_DBG_ERROR(dbg, _dwarf_error_code_from_elf_sgi_error_code(sres),
DW_DLV_ERROR);
}
ehdr_ident = ehdr.e_ident;
section_count = ehdr.e_shnum;
machine = ehdr.e_machine;
#else
if ((ehdr_ident = elf_getident(elf, NULL)) == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_GETIDENT_ERROR, DW_DLV_ERROR);
}
#endif
is_64bit = (ehdr_ident[EI_CLASS] == ELFCLASS64);
dbg->de_same_endian = 1;
dbg->de_copy_word = memcpy;
#ifdef WORDS_BIGENDIAN
dbg->de_big_endian_object = 1;
if (ehdr_ident[EI_DATA] == ELFDATA2LSB) {
dbg->de_same_endian = 0;
dbg->de_big_endian_object = 0;
dbg->de_copy_word = _dwarf_memcpy_swap_bytes;
}
#else /* little endian */
dbg->de_big_endian_object = 0;
if (ehdr_ident[EI_DATA] == ELFDATA2MSB) {
dbg->de_same_endian = 0;
dbg->de_big_endian_object = 1;
dbg->de_copy_word = _dwarf_memcpy_swap_bytes;
}
#endif /* !WORDS_BIGENDIAN */
/* The following de_length_size is Not Too Significant.
Only used one calculation, and an appoximate one at that. */
dbg->de_length_size = is_64bit ? 8 : 4;
dbg->de_pointer_size = is_64bit ? 8 : 4;
#ifdef __SGI_FAST_LIBELF
/* We've already loaded the ELF header, so there's nothing to do here */
#else
#ifdef HAVE_ELF64_GETEHDR
if (is_64bit) {
ehdr64 = elf64_getehdr(elf);
if (ehdr64 == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_GETEHDR_ERROR,
DW_DLV_ERROR);
}
section_count = ehdr64->e_shnum;
machine = ehdr64->e_machine;
} else
#endif
{
ehdr32 = elf32_getehdr(elf);
if (ehdr32 == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_GETEHDR_ERROR,
DW_DLV_ERROR);
}
section_count = ehdr32->e_shnum;
machine = ehdr32->e_machine;
}
#endif /* !defined(__SGI_FAST_LIBELF) */
if (is_64bit && machine != EM_MIPS) {
/* MIPS/IRIX makes pointer size and length size 8 for -64.
Other platforms make length 4 always. */
/* 4 here supports 32bit-offset dwarf2, as emitted by
cygnus tools, and the dwarfv2.1 64bit extension setting. */
dbg->de_length_size = 4;
}
/* We start at index 1 to skip the initial empty section. */
for (section_index = 1; section_index < section_count; ++section_index) {
#ifdef __SGI_FAST_LIBELF
sres = elf_sgi_shdr(elf, section_index, &shdr);
if (sres != ELF_SGI_ERROR_OK) {
DWARF_DBG_ERROR(dbg, _dwarf_error_code_from_elf_sgi_error_code(sres),
DW_DLV_ERROR);
}
section_size = shdr.sh_size;
sres = elf_sgi_string(elf, ehdr.e_shstrndx, shdr.sh_name, (char const** )&scn_name);
if (sres != ELF_SGI_ERROR_OK) {
DWARF_DBG_ERROR(dbg, _dwarf_error_code_from_elf_sgi_error_code(sres),
DW_DLV_ERROR);
}
#else /* !defined(__SGI_FAST_LIBELF) */
scn = elf_getscn(elf, section_index);
if (scn == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_MDE,
DW_DLV_ERROR);
}
#ifdef HAVE_ELF64_GETSHDR
if (is_64bit) {
shdr64 = elf64_getshdr(scn);
if (shdr64 == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_GETSHDR_ERROR,
DW_DLV_ERROR);
}
section_size = shdr64->sh_size;
if ((scn_name = elf_strptr(elf, ehdr64->e_shstrndx,
shdr64->sh_name))
== NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_STRPTR_ERROR,
DW_DLV_ERROR);
}
} else
#endif /* HAVE_ELF64_GETSHDR */
{
if ((shdr32 = elf32_getshdr(scn)) == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_GETSHDR_ERROR, 0);
}
section_size = shdr32->sh_size;
if ((scn_name = elf_strptr(elf, ehdr32->e_shstrndx,
shdr32->sh_name)) == NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_ELF_STRPTR_ERROR,
DW_DLV_ERROR);
}
}
#endif /* !defined(__SGI_FAST_LIBELF) */
if (strncmp(scn_name, ".debug_", 7)
&& strcmp(scn_name, ".eh_frame")
)
continue;
else if (strcmp(scn_name, ".debug_info") == 0) {
if (dbg->de_debug_info != NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_DEBUG_INFO_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* Know no reason to allow empty debug_info section */
DWARF_DBG_ERROR(dbg, DW_DLE_DEBUG_INFO_NULL,
DW_DLV_ERROR);
}
foundDwarf = TRUE;
dbg->de_debug_info_index = section_index;
dbg->de_debug_info_size = section_size;
}
else if (strcmp(scn_name, ".debug_abbrev") == 0) {
if (dbg->de_debug_abbrev != NULL) {
DWARF_DBG_ERROR(dbg, DW_DLE_DEBUG_ABBREV_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* Know no reason to allow empty debug_abbrev section */
DWARF_DBG_ERROR(dbg, DW_DLE_DEBUG_ABBREV_NULL,
DW_DLV_ERROR);
}
dbg->de_debug_abbrev_index = section_index;
dbg->de_debug_abbrev_size = section_size;
}
else if (strcmp(scn_name, ".debug_aranges") == 0) {
if (dbg->de_debug_aranges_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_ARANGES_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_aranges_index = section_index;
dbg->de_debug_aranges_size = section_size;
}
else if (strcmp(scn_name, ".debug_line") == 0) {
if (dbg->de_debug_line_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_LINE_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_line_index = section_index;
dbg->de_debug_line_size = section_size;
}
else if (strcmp(scn_name, ".debug_frame") == 0) {
if (dbg->de_debug_frame_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_FRAME_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_frame_index = section_index;
dbg->de_debug_frame_size = section_size;
foundDwarf = TRUE;
} else if (strcmp(scn_name, ".eh_frame") == 0) {
/* gnu egcs-1.1.2 data */
if (dbg->de_debug_frame_eh_gnu_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_FRAME_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_frame_eh_gnu_index = section_index;
dbg->de_debug_frame_size_eh_gnu = section_size;
foundDwarf = TRUE;
}
else if (strcmp(scn_name, ".debug_loc") == 0) {
if (dbg->de_debug_loc_index != 0) {
DWARF_DBG_ERROR(dbg, DW_DLE_DEBUG_LOC_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_loc_index = section_index;
dbg->de_debug_loc_size = section_size;
}
else if (strcmp(scn_name, ".debug_pubnames") == 0) {
if (dbg->de_debug_pubnames_index != 0) {
DWARF_DBG_ERROR(dbg, DW_DLE_DEBUG_PUBNAMES_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_pubnames_index = section_index;
dbg->de_debug_pubnames_size = section_size;
}
else if (strcmp(scn_name, ".debug_str") == 0) {
if (dbg->de_debug_str_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_STR_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_str_index = section_index;
dbg->de_debug_str_size = section_size;
}
else if (strcmp(scn_name, ".debug_funcnames") == 0) {
if (dbg->de_debug_funcnames_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_FUNCNAMES_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_funcnames_index = section_index;
dbg->de_debug_funcnames_size = section_size;
}
else if (strcmp(scn_name, ".debug_typenames") == 0) {
if (dbg->de_debug_typenames_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_TYPENAMES_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_typenames_index = section_index;
dbg->de_debug_typenames_size = section_size;
}
else if (strcmp(scn_name, ".debug_varnames") == 0) {
if (dbg->de_debug_varnames_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_VARNAMES_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_varnames_index = section_index;
dbg->de_debug_varnames_size = section_size;
}
else if (strcmp(scn_name, ".debug_weaknames") == 0) {
if (dbg->de_debug_weaknames_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_WEAKNAMES_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_weaknames_index = section_index;
dbg->de_debug_weaknames_size = section_size;
} else if (strcmp(scn_name, ".debug_macinfo") == 0) {
if (dbg->de_debug_macinfo_index != 0) {
DWARF_DBG_ERROR(dbg,
DW_DLE_DEBUG_MACINFO_DUPLICATE,
DW_DLV_ERROR);
}
if (section_size == 0) {
/* a zero size section is just empty. Ok, no error */
continue;
}
dbg->de_debug_macinfo_index = section_index;
dbg->de_debug_macinfo_size = section_size;
}
}
if (foundDwarf) {
return DW_DLV_OK;
}
return (DW_DLV_NO_ENTRY);
}
struct sr_elf_fde *
sr_elf_get_eh_frame(const char *filename,
char **error_message)
{
#ifdef WITH_ELFUTILS
/* Open the input file. */
int fd = open(filename, O_RDONLY);
if (fd < 0)
{
*error_message = sr_asprintf("Failed to open file %s: %s",
filename,
strerror(errno));
return NULL;
}
/* Initialize libelf on the opened file. */
Elf *elf = elf_begin(fd, ELF_C_READ, NULL);
if (!elf)
{
*error_message = sr_asprintf("Failed to run elf_begin on file %s: %s",
filename,
elf_errmsg(-1));
close(fd);
return NULL;
}
unsigned char *e_ident = (unsigned char *)elf_getident(elf, NULL);
if (!e_ident)
{
*error_message = sr_asprintf("elf_getident failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
/* Look up the .eh_frame section */
GElf_Shdr shdr;
Elf_Data *section_data;
char *find_section_error_message;
if (!find_elf_section_by_name(elf,
".eh_frame",
§ion_data,
&shdr,
&find_section_error_message))
{
*error_message = sr_asprintf("Failed to find .eh_frame section for %s: %s",
filename,
find_section_error_message);
free(find_section_error_message);
elf_end(elf);
close(fd);
return NULL;
}
/* Get the address at which the executable segment is loaded. If
* the .eh_frame addresses are absolute, this is used to convert
* them to relative to the beginning of executable segment. We
* are looking for the first LOAD segment that is executable, I
* hope this is sufficient.
*/
size_t phnum;
if (elf_getphdrnum(elf, &phnum) != 0)
{
*error_message = sr_asprintf("elf_getphdrnum failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
uint64_t exec_base = -1;
int i;
for (i = 0; i < phnum; i++)
{
GElf_Phdr phdr;
if (gelf_getphdr(elf, i, &phdr) != &phdr)
{
*error_message = sr_asprintf("gelf_getphdr failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
if (phdr.p_type == PT_LOAD && phdr.p_flags & PF_X)
{
exec_base = phdr.p_vaddr;
break;
}
}
if (-1 == exec_base)
{
*error_message = sr_asprintf("Can't determine executable base for %s",
filename);
elf_end(elf);
close(fd);
return NULL;
}
/* We now have a handle to .eh_frame data. We'll use
* dwarf_next_cfi to iterate through all FDEs looking for those
* matching the addresses we have.
*
* Some info on .eh_frame can be found at
* http://www.airs.com/blog/archives/460 and in DWARF
* documentation for .debug_frame. The initial_location and
* address_range decoding is 'inspired' by elfutils source.
*
* @todo If this linear scan is too slow, we can do binary search
* on .eh_frame_hdr -- see http://www.airs.com/blog/archives/462
*/
struct sr_elf_fde *result = NULL, *last = NULL;
struct cie *cie_list = NULL, *cie_list_last = NULL;
Dwarf_Off cfi_offset_next = 0;
while (true)
{
Dwarf_CFI_Entry cfi;
Dwarf_Off cfi_offset = cfi_offset_next;
int ret = dwarf_next_cfi(e_ident,
section_data,
1,
cfi_offset,
&cfi_offset_next,
&cfi);
if (ret > 0)
{
/* We're at the end. */
break;
}
if (ret < 0)
{
/* Error. If cfi_offset_next was updated, we may skip the
* erroneous cfi. */
if (cfi_offset_next > cfi_offset)
continue;
*error_message = sr_asprintf("dwarf_next_cfi failed for %s: %s",
filename,
dwarf_errmsg(-1));
cie_free(cie_list);
sr_elf_eh_frame_free(result);
elf_end(elf);
close(fd);
return NULL;
}
if (dwarf_cfi_cie_p(&cfi))
{
/* Current CFI is a CIE. We store its offset and FDE encoding
* attributes to be used when reading FDEs.
*/
/* Default FDE encoding (i.e. no R in augmentation string) is
* DW_EH_PE_absptr.
*/
char *cie_error_message;
struct cie *cie = read_cie(&cfi,
cfi_offset,
e_ident,
&cie_error_message);
if (!cie)
{
*error_message = sr_asprintf("CIE reading failed for %s: %s",
filename,
cie_error_message);
free(cie_error_message);
cie_free(cie_list);
sr_elf_eh_frame_free(result);
elf_end(elf);
close(fd);
return NULL;
}
/* Append the newly parsed CIE to our list of CIEs. */
if (cie_list)
{
cie_list_last->next = cie;
cie_list_last = cie;
}
else
cie_list = cie_list_last = cie;
}
else
{
/* Current CFI is an FDE.
*/
struct cie *cie = cie_list;
/* Find the CIE data that we should have saved earlier. */
while (cie)
{
/* In .eh_frame, CIE_pointer is relative, but libdw converts it
* to absolute offset. */
if (cfi.fde.CIE_pointer == cie->cie_offset)
break; /* Found. */
cie = cie->next;
}
if (!cie)
{
*error_message = sr_asprintf("CIE not found for FDE %jx in %s",
(uintmax_t)cfi_offset,
filename);
cie_free(cie_list);
sr_elf_eh_frame_free(result);
elf_end(elf);
close(fd);
return NULL;
}
/* Read the two numbers we need and if they are PC-relative,
* compute the offset from VMA base
*/
uint64_t initial_location = fde_read_address(cfi.fde.start,
cie->ptr_len);
uint64_t address_range = fde_read_address(cfi.fde.start + cie->ptr_len,
cie->ptr_len);
if (cie->pcrel)
{
/* We need to determine how long is the 'length' (and
* consequently CIE id) field of this FDE -- it can be
* either 4 or 12 bytes long. */
uint64_t length = fde_read_address(section_data->d_buf + cfi_offset, 4);
uint64_t skip = (length == 0xffffffffUL ? 12 : 4);
uint64_t mask = (cie->ptr_len == 4 ? 0xffffffffUL : 0xffffffffffffffffUL);
initial_location += shdr.sh_offset + cfi_offset + 2 * skip;
initial_location &= mask;
}
else
{
/* Assuming that not pcrel means absolute address
* (what if the file is a library?). Convert to
* text-section-start-relative.
*/
initial_location -= exec_base;
}
struct sr_elf_fde *fde = sr_malloc(sizeof(struct sr_elf_fde));
fde->exec_base = exec_base;
fde->start_address = initial_location;
fde->length = address_range;
fde->next = NULL;
/* Append the newly parsed Frame Description Entry to our
* list of FDEs.
*/
if (result)
{
last->next = fde;
last = fde;
}
else
result = last = fde;
}
}
cie_free(cie_list);
elf_end(elf);
close(fd);
return result;
#else /* WITH_ELFUTILS */
*error_message = sr_asprintf("satyr compiled without elfutils");
return NULL;
#endif /* WITH_ELFUTILS */
}
int init(char* fname)
{
char *id, bytes[5];
if (elf_version (EV_CURRENT) == EV_NONE) {
errx (EXIT_FAILURE, " ELF library initialization "
" failed : %s", elf_errmsg (-1));
return -1;
}
int fd;
if ((fd = open (fname, O_RDONLY, 0)) < 0) {
err (EXIT_FAILURE, " open \"%s\" failed ", fname);
return -1;
}
g.fd = fd;
Elf *e;
if ((e = elf_begin (fd, ELF_C_READ, NULL)) == NULL) {
errx (EXIT_FAILURE, " elf_begin () failed : %s.",
elf_errmsg (-1));
return -1;
}
if (elf_kind (e) != ELF_K_ELF) {
errx (EXIT_FAILURE, " \"%s\" is not an ELF object .",
fname);
return -1;
}
g.e = e;
GElf_Ehdr ehdr;
if (gelf_getehdr (e, &ehdr) == NULL) {
errx (EXIT_FAILURE, " getehdr () failed : %s.",
elf_errmsg (-1));
return -1;
}
g.ehdr = ehdr;
int i;
if ((i = gelf_getclass (e)) == ELFCLASSNONE) {
errx (EXIT_FAILURE, " getclass () failed : %s.",
elf_errmsg (-1));
return -1;
}
if ((id = elf_getident (e, NULL)) == NULL) {
errx (EXIT_FAILURE, " getident () failed : %s.",
elf_errmsg (-1));
return -1;
}
size_t n;
if (elf_getshdrnum (e, &n) != 0) {
errx (EXIT_FAILURE, " getshdrnum () failed : %s.",
elf_errmsg (-1));
return -1;
}
g.shdrnum = n;
if (elf_getshdrstrndx (e, &n) != 0) {
errx (EXIT_FAILURE, " getshdrstrndx () failed : %s.",
elf_errmsg (-1));
return -1;
}
g.shstrndx = n;
if (elf_getphdrnum (e, &n) != 0) {
errx (EXIT_FAILURE, " getphdrnum () failed : %s.",
elf_errmsg (-1));
return -1;
}
g.phdrnum = n;
init_scns();
init_phdrs();
return 0;
}
static const value_t *
elf_get_ehdr(const value_t *this_fn, parser_state_t *state,
const char *filename, int binfd,
Elf *e, GElf_Ehdr *ehdr, void *arg)
{
int eclass = gelf_getclass(e);
char *id = elf_getident(e, NULL);
dir_t *einfo = dir_id_new();
dir_t *edir = dir_id_new();
size_t n;
if (eclass == ELFCLASS32)
dir_string_set(einfo, "class", value_int_new(32));
else if (eclass == ELFCLASS64)
dir_string_set(einfo, "class", value_int_new(64));
else {
dir_string_set(einfo, "class", &value_null);
if (eclass != ELFCLASSNONE)
parser_report(state, "ELF file has unknown class %d - %s\n",
eclass, elf_errmsg(-1));
}
if (id == NULL)
parser_report(state, "ELF file has unknown identity - %s\n",
elf_errmsg(-1));
else
dir_string_set(einfo, "id",
value_string_new(id, EI_NIDENT));
dir_string_set(einfo, "ehdr", dir_value(edir));
dir_string_set(edir,"type" , value_int_new(ehdr->e_type));
dir_string_set(edir,"machine", value_int_new(ehdr->e_machine));
dir_string_set(edir,"version", value_int_new(ehdr->e_version));
dir_string_set(edir,"entry" , value_int_new(ehdr->e_entry));
dir_string_set(edir,"phoff" , value_int_new(ehdr->e_phoff));
dir_string_set(edir,"shoff" , value_int_new(ehdr->e_shoff));
dir_string_set(edir,"flags" , value_int_new(ehdr->e_flags));
dir_string_set(edir,"ehsize" , value_int_new(ehdr->e_ehsize));
dir_string_set(edir,"phentsize",
value_int_new(ehdr->e_phentsize));
dir_string_set(edir,"shentsize",
value_int_new(ehdr->e_shentsize));
if (elf_getphdrnum(e, &n) != 0)
parser_report(state,"ELF file has unknown number of segments - %s\n",
elf_errmsg(-1));
else
dir_string_set(einfo, "progsects", value_int_new(n));
if (elf_getshdrnum(e, &n) != 0)
parser_report(state, "%s: ELF file has unknown number of sections - %s\n",
elf_errmsg(-1));
else
dir_string_set(einfo, "sections", value_int_new(n));
if (elf_getshdrstrndx(e, &n) != 0)
parser_report(state, "%s: ELF file has no section names - %s\n",
elf_errmsg(-1));
else
dir_string_set(einfo, "shdrstrndx", value_int_new(n));
return dir_value(einfo);
}
/* If the main file might have been prelinked, then we need to
discover the correct synchronization address between the main and
debug files. Because of prelink's section juggling, we cannot rely
on the address_sync computed from PT_LOAD segments (see open_elf).
We will attempt to discover a synchronization address based on the
section headers instead. But finding a section address that is
safe to use requires identifying which sections are SHT_PROGBITS.
We can do that in the main file, but in the debug file all the
allocated sections have been transformed into SHT_NOBITS so we have
lost the means to match them up correctly.
The only method left to us is to decode the .gnu.prelink_undo
section in the prelinked main file. This shows what the sections
looked like before prelink juggled them--when they still had a
direct correspondence to the debug file. */
static Dwfl_Error
find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
{
/* The magic section is only identified by name. */
size_t shstrndx;
if (elf_getshdrstrndx (mod->main.elf, &shstrndx) < 0)
return DWFL_E_LIBELF;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if (unlikely (shdr == NULL))
return DWFL_E_LIBELF;
if (shdr->sh_type == SHT_PROGBITS
&& !(shdr->sh_flags & SHF_ALLOC)
&& shdr->sh_name != 0)
{
const char *secname = elf_strptr (mod->main.elf, shstrndx,
shdr->sh_name);
if (unlikely (secname == NULL))
return DWFL_E_LIBELF;
if (!strcmp (secname, ".gnu.prelink_undo"))
break;
}
}
if (scn == NULL)
/* There was no .gnu.prelink_undo section. */
return DWFL_E_NOERROR;
Elf_Data *undodata = elf_rawdata (scn, NULL);
if (unlikely (undodata == NULL))
return DWFL_E_LIBELF;
/* Decode the section. It consists of the original ehdr, phdrs,
and shdrs (but omits section 0). */
union
{
Elf32_Ehdr e32;
Elf64_Ehdr e64;
} ehdr;
Elf_Data dst =
{
.d_buf = &ehdr,
.d_size = sizeof ehdr,
.d_type = ELF_T_EHDR,
.d_version = EV_CURRENT
};
Elf_Data src = *undodata;
src.d_size = gelf_fsize (mod->main.elf, ELF_T_EHDR, 1, EV_CURRENT);
src.d_type = ELF_T_EHDR;
if (unlikely (gelf_xlatetom (mod->main.elf, &dst, &src,
elf_getident (mod->main.elf, NULL)[EI_DATA])
== NULL))
return DWFL_E_LIBELF;
size_t shentsize = gelf_fsize (mod->main.elf, ELF_T_SHDR, 1, EV_CURRENT);
size_t phentsize = gelf_fsize (mod->main.elf, ELF_T_PHDR, 1, EV_CURRENT);
uint_fast16_t phnum;
uint_fast16_t shnum;
if (ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32)
{
if (ehdr.e32.e_shentsize != shentsize
|| ehdr.e32.e_phentsize != phentsize)
return DWFL_E_BAD_PRELINK;
phnum = ehdr.e32.e_phnum;
shnum = ehdr.e32.e_shnum;
}
else
{
if (ehdr.e64.e_shentsize != shentsize
|| ehdr.e64.e_phentsize != phentsize)
return DWFL_E_BAD_PRELINK;
phnum = ehdr.e64.e_phnum;
shnum = ehdr.e64.e_shnum;
}
/* Since prelink does not store the zeroth section header in the undo
section, it cannot support SHN_XINDEX encoding. */
if (unlikely (shnum >= SHN_LORESERVE)
|| unlikely (undodata->d_size != (src.d_size
+ phnum * phentsize
+ (shnum - 1) * shentsize)))
return DWFL_E_BAD_PRELINK;
/* We look at the allocated SHT_PROGBITS (or SHT_NOBITS) sections. (Most
every file will have some SHT_PROGBITS sections, but it's possible to
have one with nothing but .bss, i.e. SHT_NOBITS.) The special sections
that can be moved around have different sh_type values--except for
.interp, the section that became the PT_INTERP segment. So we exclude
the SHT_PROGBITS section whose address matches the PT_INTERP p_vaddr.
For this reason, we must examine the phdrs first to find PT_INTERP. */
GElf_Addr main_interp = 0;
{
size_t main_phnum;
if (unlikely (elf_getphdrnum (mod->main.elf, &main_phnum)))
return DWFL_E_LIBELF;
for (size_t i = 0; i < main_phnum; ++i)
{
GElf_Phdr phdr;
if (unlikely (gelf_getphdr (mod->main.elf, i, &phdr) == NULL))
return DWFL_E_LIBELF;
if (phdr.p_type == PT_INTERP)
{
main_interp = phdr.p_vaddr;
break;
}
}
}
src.d_buf += src.d_size;
src.d_type = ELF_T_PHDR;
src.d_size = phnum * phentsize;
GElf_Addr undo_interp = 0;
bool class32 = ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32;
{
size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
if (unlikely (phnum > SIZE_MAX / phdr_size))
return DWFL_E_NOMEM;
const size_t phdrs_bytes = phnum * phdr_size;
void *phdrs = malloc (phdrs_bytes);
if (unlikely (phdrs == NULL))
return DWFL_E_NOMEM;
dst.d_buf = phdrs;
dst.d_size = phdrs_bytes;
if (unlikely (gelf_xlatetom (mod->main.elf, &dst, &src,
ehdr.e32.e_ident[EI_DATA]) == NULL))
{
free (phdrs);
return DWFL_E_LIBELF;
}
if (class32)
{
Elf32_Phdr (*p32)[phnum] = phdrs;
for (uint_fast16_t i = 0; i < phnum; ++i)
if ((*p32)[i].p_type == PT_INTERP)
{
undo_interp = (*p32)[i].p_vaddr;
break;
}
}
else
{
Elf64_Phdr (*p64)[phnum] = phdrs;
for (uint_fast16_t i = 0; i < phnum; ++i)
if ((*p64)[i].p_type == PT_INTERP)
{
undo_interp = (*p64)[i].p_vaddr;
break;
}
}
free (phdrs);
}
if (unlikely ((main_interp == 0) != (undo_interp == 0)))
return DWFL_E_BAD_PRELINK;
src.d_buf += src.d_size;
src.d_type = ELF_T_SHDR;
src.d_size = gelf_fsize (mod->main.elf, ELF_T_SHDR, shnum - 1, EV_CURRENT);
size_t shdr_size = class32 ? sizeof (Elf32_Shdr) : sizeof (Elf64_Shdr);
if (unlikely (shnum - 1 > SIZE_MAX / shdr_size))
return DWFL_E_NOMEM;
const size_t shdrs_bytes = (shnum - 1) * shdr_size;
void *shdrs = malloc (shdrs_bytes);
if (unlikely (shdrs == NULL))
return DWFL_E_NOMEM;
dst.d_buf = shdrs;
dst.d_size = shdrs_bytes;
if (unlikely (gelf_xlatetom (mod->main.elf, &dst, &src,
ehdr.e32.e_ident[EI_DATA]) == NULL))
{
free (shdrs);
return DWFL_E_LIBELF;
}
/* Now we can look at the original section headers of the main file
before it was prelinked. First we'll apply our method to the main
file sections as they are after prelinking, to calculate the
synchronization address of the main file. Then we'll apply that
same method to the saved section headers, to calculate the matching
synchronization address of the debug file.
The method is to consider SHF_ALLOC sections that are either
SHT_PROGBITS or SHT_NOBITS, excluding the section whose sh_addr
matches the PT_INTERP p_vaddr. The special sections that can be
moved by prelink have other types, except for .interp (which
becomes PT_INTERP). The "real" sections cannot move as such, but
.bss can be split into .dynbss and .bss, with the total memory
image remaining the same but being spread across the two sections.
So we consider the highest section end, which still matches up. */
GElf_Addr highest;
inline void consider_shdr (GElf_Addr interp,
GElf_Word sh_type,
GElf_Xword sh_flags,
GElf_Addr sh_addr,
GElf_Xword sh_size)
{
if ((sh_flags & SHF_ALLOC)
&& ((sh_type == SHT_PROGBITS && sh_addr != interp)
|| sh_type == SHT_NOBITS))
{
const GElf_Addr sh_end = sh_addr + sh_size;
if (sh_end > highest)
highest = sh_end;
}
}
highest = 0;
scn = NULL;
while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
{
GElf_Shdr sh_mem;
GElf_Shdr *sh = gelf_getshdr (scn, &sh_mem);
if (unlikely (sh == NULL))
{
free (shdrs);
return DWFL_E_LIBELF;
}
consider_shdr (main_interp, sh->sh_type, sh->sh_flags,
sh->sh_addr, sh->sh_size);
}
if (highest > mod->main.vaddr)
{
mod->main.address_sync = highest;
highest = 0;
if (class32)
{
Elf32_Shdr (*s32)[shnum - 1] = shdrs;
for (size_t i = 0; i < shnum - 1; ++i)
consider_shdr (undo_interp, (*s32)[i].sh_type,
(*s32)[i].sh_flags, (*s32)[i].sh_addr,
(*s32)[i].sh_size);
}
else
{
Elf64_Shdr (*s64)[shnum - 1] = shdrs;
for (size_t i = 0; i < shnum - 1; ++i)
consider_shdr (undo_interp, (*s64)[i].sh_type,
(*s64)[i].sh_flags, (*s64)[i].sh_addr,
(*s64)[i].sh_size);
}
if (highest > file->vaddr)
file->address_sync = highest;
else
{
free (shdrs);
return DWFL_E_BAD_PRELINK;
}
}
free (shdrs);
return DWFL_E_NOERROR;
}
/* Find the separate debuginfo file for this module and open libelf on it.
When we return success, MOD->debug is set up. */
static Dwfl_Error
find_debuginfo (Dwfl_Module *mod)
{
if (mod->debug.elf != NULL)
return DWFL_E_NOERROR;
GElf_Word debuglink_crc = 0;
const char *debuglink_file;
debuglink_file = INTUSE(dwelf_elf_gnu_debuglink) (mod->main.elf,
&debuglink_crc);
mod->debug.fd = (*mod->dwfl->callbacks->find_debuginfo) (MODCB_ARGS (mod),
mod->main.name,
debuglink_file,
debuglink_crc,
&mod->debug.name);
Dwfl_Error result = open_elf (mod, &mod->debug);
if (result == DWFL_E_NOERROR && mod->debug.address_sync != 0)
result = find_prelink_address_sync (mod, &mod->debug);
return result;
}
/* Try to find the alternative debug link for the given DWARF and set
it if found. Only called when mod->dw is already setup but still
might need an alternative (dwz multi) debug file. filename is either
the main or debug name from which the Dwarf was created. */
static void
find_debug_altlink (Dwfl_Module *mod, const char *filename)
{
assert (mod->dw != NULL);
const char *altname;
const void *build_id;
ssize_t build_id_len = INTUSE(dwelf_dwarf_gnu_debugaltlink) (mod->dw,
&altname,
&build_id);
if (build_id_len > 0)
{
/* We could store altfile in the module, but don't really need it. */
char *altfile = NULL;
mod->alt_fd = (*mod->dwfl->callbacks->find_debuginfo) (MODCB_ARGS (mod),
filename,
altname,
0,
&altfile);
/* The (internal) callbacks might just set mod->alt_elf directly
because they open the Elf anyway for sanity checking.
Otherwise open either the given file name or use the fd
returned. */
Dwfl_Error error = open_elf_file (&mod->alt_elf, &mod->alt_fd,
&altfile);
if (error == DWFL_E_NOERROR)
{
mod->alt = INTUSE(dwarf_begin_elf) (mod->alt_elf,
DWARF_C_READ, NULL);
if (mod->alt == NULL)
{
elf_end (mod->alt_elf);
mod->alt_elf = NULL;
close (mod->alt_fd);
mod->alt_fd = -1;
}
else
dwarf_setalt (mod->dw, mod->alt);
}
free (altfile); /* See above, we don't really need it. */
}
}
/* Search an ELF file for a ".gnu_debuglink" section. */
static const char *
find_debuglink (Elf *elf, GElf_Word *crc)
{
size_t shstrndx;
if (elf_getshdrstrndx (elf, &shstrndx) < 0)
return NULL;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (elf, scn)) != NULL)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if (shdr == NULL)
return NULL;
const char *name = elf_strptr (elf, shstrndx, shdr->sh_name);
if (name == NULL)
return NULL;
if (!strcmp (name, ".gnu_debuglink"))
break;
}
if (scn == NULL)
return NULL;
/* Found the .gnu_debuglink section. Extract its contents. */
Elf_Data *rawdata = elf_rawdata (scn, NULL);
if (rawdata == NULL)
return NULL;
Elf_Data crcdata =
{
.d_type = ELF_T_WORD,
.d_buf = crc,
.d_size = sizeof *crc,
.d_version = EV_CURRENT,
};
Elf_Data conv =
{
.d_type = ELF_T_WORD,
.d_buf = rawdata->d_buf + rawdata->d_size - sizeof *crc,
.d_size = sizeof *crc,
.d_version = EV_CURRENT,
};
GElf_Ehdr ehdr_mem;
GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
if (ehdr == NULL)
return NULL;
Elf_Data *d = gelf_xlatetom (elf, &crcdata, &conv, ehdr->e_ident[EI_DATA]);
if (d == NULL)
return NULL;
assert (d == &crcdata);
return rawdata->d_buf;
}
/* If the main file might have been prelinked, then we need to
discover the correct synchronization address between the main and
debug files. Because of prelink's section juggling, we cannot rely
on the address_sync computed from PT_LOAD segments (see open_elf).
We will attempt to discover a synchronization address based on the
section headers instead. But finding a section address that is
safe to use requires identifying which sections are SHT_PROGBITS.
We can do that in the main file, but in the debug file all the
allocated sections have been transformed into SHT_NOBITS so we have
lost the means to match them up correctly.
The only method left to us is to decode the .gnu.prelink_undo
section in the prelinked main file. This shows what the sections
looked like before prelink juggled them--when they still had a
direct correspondence to the debug file. */
static Dwfl_Error
find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
{
/* The magic section is only identified by name. */
size_t shstrndx;
if (elf_getshdrstrndx (mod->main.elf, &shstrndx) < 0)
return DWFL_E_LIBELF;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if (unlikely (shdr == NULL))
return DWFL_E_LIBELF;
if (shdr->sh_type == SHT_PROGBITS
&& !(shdr->sh_flags & SHF_ALLOC)
&& shdr->sh_name != 0)
{
const char *secname = elf_strptr (mod->main.elf, shstrndx,
shdr->sh_name);
if (unlikely (secname == NULL))
return DWFL_E_LIBELF;
if (!strcmp (secname, ".gnu.prelink_undo"))
break;
}
}
if (scn == NULL)
/* There was no .gnu.prelink_undo section. */
return DWFL_E_NOERROR;
Elf_Data *undodata = elf_rawdata (scn, NULL);
if (unlikely (undodata == NULL))
return DWFL_E_LIBELF;
/* Decode the section. It consists of the original ehdr, phdrs,
and shdrs (but omits section 0). */
union
{
Elf32_Ehdr e32;
Elf64_Ehdr e64;
} ehdr;
Elf_Data dst =
{
.d_buf = &ehdr,
.d_size = sizeof ehdr,
.d_type = ELF_T_EHDR,
.d_version = EV_CURRENT
};
Elf_Data src = *undodata;
src.d_size = gelf_fsize (mod->main.elf, ELF_T_EHDR, 1, EV_CURRENT);
src.d_type = ELF_T_EHDR;
if (unlikely (gelf_xlatetom (mod->main.elf, &dst, &src,
elf_getident (mod->main.elf, NULL)[EI_DATA])
== NULL))
return DWFL_E_LIBELF;
size_t shentsize = gelf_fsize (mod->main.elf, ELF_T_SHDR, 1, EV_CURRENT);
size_t phentsize = gelf_fsize (mod->main.elf, ELF_T_PHDR, 1, EV_CURRENT);
uint_fast16_t phnum;
uint_fast16_t shnum;
if (ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32)
{
if (ehdr.e32.e_shentsize != shentsize
|| ehdr.e32.e_phentsize != phentsize)
return DWFL_E_BAD_PRELINK;
phnum = ehdr.e32.e_phnum;
shnum = ehdr.e32.e_shnum;
}
else
{
if (ehdr.e64.e_shentsize != shentsize
|| ehdr.e64.e_phentsize != phentsize)
return DWFL_E_BAD_PRELINK;
phnum = ehdr.e64.e_phnum;
shnum = ehdr.e64.e_shnum;
}
/* Since prelink does not store the zeroth section header in the undo
section, it cannot support SHN_XINDEX encoding. */
if (unlikely (shnum >= SHN_LORESERVE)
|| unlikely (undodata->d_size != (src.d_size
+ phnum * phentsize
+ (shnum - 1) * shentsize)))
return DWFL_E_BAD_PRELINK;
/* We look at the allocated SHT_PROGBITS (or SHT_NOBITS) sections. (Most
every file will have some SHT_PROGBITS sections, but it's possible to
have one with nothing but .bss, i.e. SHT_NOBITS.) The special sections
that can be moved around have different sh_type values--except for
.interp, the section that became the PT_INTERP segment. So we exclude
the SHT_PROGBITS section whose address matches the PT_INTERP p_vaddr.
For this reason, we must examine the phdrs first to find PT_INTERP. */
GElf_Addr main_interp = 0;
{
size_t main_phnum;
if (unlikely (elf_getphdrnum (mod->main.elf, &main_phnum)))
return DWFL_E_LIBELF;
for (size_t i = 0; i < main_phnum; ++i)
{
GElf_Phdr phdr;
if (unlikely (gelf_getphdr (mod->main.elf, i, &phdr) == NULL))
return DWFL_E_LIBELF;
if (phdr.p_type == PT_INTERP)
{
main_interp = phdr.p_vaddr;
break;
}
}
}
src.d_buf += src.d_size;
src.d_type = ELF_T_PHDR;
src.d_size = phnum * phentsize;
GElf_Addr undo_interp = 0;
{
union
{
Elf32_Phdr p32[phnum];
Elf64_Phdr p64[phnum];
} phdr;
dst.d_buf = &phdr;
dst.d_size = sizeof phdr;
if (unlikely (gelf_xlatetom (mod->main.elf, &dst, &src,
ehdr.e32.e_ident[EI_DATA]) == NULL))
return DWFL_E_LIBELF;
if (ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32)
{
for (uint_fast16_t i = 0; i < phnum; ++i)
if (phdr.p32[i].p_type == PT_INTERP)
{
undo_interp = phdr.p32[i].p_vaddr;
break;
}
}
else
{
for (uint_fast16_t i = 0; i < phnum; ++i)
if (phdr.p64[i].p_type == PT_INTERP)
{
undo_interp = phdr.p64[i].p_vaddr;
break;
}
}
}
if (unlikely ((main_interp == 0) != (undo_interp == 0)))
return DWFL_E_BAD_PRELINK;
src.d_buf += src.d_size;
src.d_type = ELF_T_SHDR;
src.d_size = gelf_fsize (mod->main.elf, ELF_T_SHDR, shnum - 1, EV_CURRENT);
union
{
Elf32_Shdr s32[shnum - 1];
Elf64_Shdr s64[shnum - 1];
} shdr;
dst.d_buf = &shdr;
dst.d_size = sizeof shdr;
if (unlikely (gelf_xlatetom (mod->main.elf, &dst, &src,
ehdr.e32.e_ident[EI_DATA]) == NULL))
return DWFL_E_LIBELF;
/* Now we can look at the original section headers of the main file
before it was prelinked. First we'll apply our method to the main
file sections as they are after prelinking, to calculate the
synchronization address of the main file. Then we'll apply that
same method to the saved section headers, to calculate the matching
synchronization address of the debug file.
The method is to consider SHF_ALLOC sections that are either
SHT_PROGBITS or SHT_NOBITS, excluding the section whose sh_addr
matches the PT_INTERP p_vaddr. The special sections that can be
moved by prelink have other types, except for .interp (which
becomes PT_INTERP). The "real" sections cannot move as such, but
.bss can be split into .dynbss and .bss, with the total memory
image remaining the same but being spread across the two sections.
So we consider the highest section end, which still matches up. */
GElf_Addr highest;
inline void consider_shdr (GElf_Addr interp,
GElf_Word sh_type,
GElf_Xword sh_flags,
GElf_Addr sh_addr,
GElf_Xword sh_size)
{
if ((sh_flags & SHF_ALLOC)
&& ((sh_type == SHT_PROGBITS && sh_addr != interp)
|| sh_type == SHT_NOBITS))
{
const GElf_Addr sh_end = sh_addr + sh_size;
if (sh_end > highest)
highest = sh_end;
}
}
highest = 0;
scn = NULL;
while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
{
GElf_Shdr sh_mem;
GElf_Shdr *sh = gelf_getshdr (scn, &sh_mem);
if (unlikely (sh == NULL))
return DWFL_E_LIBELF;
consider_shdr (main_interp, sh->sh_type, sh->sh_flags,
sh->sh_addr, sh->sh_size);
}
if (highest > mod->main.vaddr)
{
mod->main.address_sync = highest;
highest = 0;
if (ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32)
for (size_t i = 0; i < shnum - 1; ++i)
consider_shdr (undo_interp, shdr.s32[i].sh_type, shdr.s32[i].sh_flags,
shdr.s32[i].sh_addr, shdr.s32[i].sh_size);
else
for (size_t i = 0; i < shnum - 1; ++i)
consider_shdr (undo_interp, shdr.s64[i].sh_type, shdr.s64[i].sh_flags,
shdr.s64[i].sh_addr, shdr.s64[i].sh_size);
if (highest > file->vaddr)
file->address_sync = highest;
else
return DWFL_E_BAD_PRELINK;
}
return DWFL_E_NOERROR;
}
/* Find the separate debuginfo file for this module and open libelf on it.
When we return success, MOD->debug is set up. */
static Dwfl_Error
find_debuginfo (Dwfl_Module *mod)
{
if (mod->debug.elf != NULL)
return DWFL_E_NOERROR;
GElf_Word debuglink_crc = 0;
const char *debuglink_file = find_debuglink (mod->main.elf, &debuglink_crc);
mod->debug.fd = (*mod->dwfl->callbacks->find_debuginfo) (MODCB_ARGS (mod),
mod->main.name,
debuglink_file,
debuglink_crc,
&mod->debug.name);
Dwfl_Error result = open_elf (mod, &mod->debug);
if (result == DWFL_E_NOERROR && mod->debug.address_sync != 0)
result = find_prelink_address_sync (mod, &mod->debug);
return result;
}
/* Try to find a symbol table in FILE.
Returns DWFL_E_NOERROR if a proper one is found.
Returns DWFL_E_NO_SYMTAB if not, but still sets results for SHT_DYNSYM. */
static Dwfl_Error
load_symtab (struct dwfl_file *file, struct dwfl_file **symfile,
Elf_Scn **symscn, Elf_Scn **xndxscn,
size_t *syments, int *first_global, GElf_Word *strshndx)
{
bool symtab = false;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (file->elf, scn)) != NULL)
{
GElf_Shdr shdr_mem, *shdr = gelf_getshdr (scn, &shdr_mem);
if (shdr != NULL)
switch (shdr->sh_type)
{
case SHT_SYMTAB:
symtab = true;
*symscn = scn;
*symfile = file;
*strshndx = shdr->sh_link;
*syments = shdr->sh_size / shdr->sh_entsize;
*first_global = shdr->sh_info;
if (*xndxscn != NULL)
return DWFL_E_NOERROR;
break;
case SHT_DYNSYM:
if (symtab)
break;
/* Use this if need be, but keep looking for SHT_SYMTAB. */
*symscn = scn;
*symfile = file;
*strshndx = shdr->sh_link;
*syments = shdr->sh_size / shdr->sh_entsize;
*first_global = shdr->sh_info;
break;
case SHT_SYMTAB_SHNDX:
*xndxscn = scn;
if (symtab)
return DWFL_E_NOERROR;
break;
default:
break;
}
}
if (symtab)
/* We found one, though no SHT_SYMTAB_SHNDX to go with it. */
return DWFL_E_NOERROR;
/* We found no SHT_SYMTAB, so any SHT_SYMTAB_SHNDX was bogus.
We might have found an SHT_DYNSYM and set *SYMSCN et al though. */
*xndxscn = NULL;
return DWFL_E_NO_SYMTAB;
}
/* Translate addresses into file offsets.
OFFS[*] start out zero and remain zero if unresolved. */
static void
find_offsets (Elf *elf, size_t phnum, size_t n,
GElf_Addr addrs[n], GElf_Off offs[n])
{
size_t unsolved = n;
for (size_t i = 0; i < phnum; ++i)
{
GElf_Phdr phdr_mem;
GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
if (phdr != NULL && phdr->p_type == PT_LOAD && phdr->p_memsz > 0)
for (size_t j = 0; j < n; ++j)
if (offs[j] == 0
&& addrs[j] >= phdr->p_vaddr
&& addrs[j] - phdr->p_vaddr < phdr->p_filesz)
{
offs[j] = addrs[j] - phdr->p_vaddr + phdr->p_offset;
if (--unsolved == 0)
break;
}
}
}
/**
* Load an abs file into DSP memory and get a reference to the entry point.
* The entry point can only e considered valid if loading succeeds. You can later
* use the obtained entry point to start program execution.
*
* Make sure you have set up any abs filters you need BEFORE calling this function.
*
* For a reasonable set of default flags use ABSLOAD_FLAG_DEFAULT. This should be
* good for 99% of cases.
*
* Normally, you can only load code when the core is not running (cold or idle).
* However, in some weird cases you may want to override this check. This can be
* done via ABSLOAD_FLAG_FORCE. Just don't shoot yourself in the knee.
*
* @param h device handle
* @param path file path
* @param ep a pointer to uint32_t, will be used to store entry point if loading succeeds.
* @param flags one or more ABSLOAD_FLAG_*
* @return
*/
int easynmc_load_abs(struct easynmc_handle *h, const char *path, uint32_t* ep, int flags)
{
int i;
char *id;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf *elf;
int fd;
Elf_Scn *scn = NULL;
const char *state = easynmc_state_name(easynmc_core_state(h));
if (!(flags & ABSLOAD_FLAG_FORCE))
if ((easynmc_core_state(h) == EASYNMC_CORE_RUNNING) ||
(easynmc_core_state(h) == EASYNMC_CORE_KILLABLE) ||
(easynmc_core_state(h) == EASYNMC_CORE_INVALID))
{
err("ERROR: Attempt to load abs when core is '%s'\n", state);
err("ERROR: Will not do that unless --force'd\n");
return 1;
}
FILE* rfd = fopen(path, "rb");
if (NULL==rfd) {
perror("fopen");
return -1;
}
if ((fd = open(path, O_RDONLY)) == -1) {
perror("open");
goto errfclose;
}
if(elf_version(EV_CURRENT) == EV_NONE)
{
err("WARNING: Elf Library is out of date!\n");
}
if ((elf = elf_begin(fd, ELF_C_READ , NULL)) == NULL) {
err("elf_begin() failed: %s.",
elf_errmsg(-1));
goto errclose;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
err( "getehdr() failed: %s.",
elf_errmsg(-1));
goto errclose;
}
if ((i = gelf_getclass(elf)) == ELFCLASSNONE) {
err( "getclass() failed: %s.",
elf_errmsg(-1));
goto errclose;
}
dbg("ELF Looks like a %d-bit ELF object\n",
i == ELFCLASS32 ? 32 : 64);
if ((id = elf_getident(elf, NULL)) == NULL) {
err( "getident() failed: %s.",
elf_errmsg(-1));
goto errclose;
}
dbg("ELF Machine id: 0x%x\n", ehdr.e_machine);
*ep = ehdr.e_entry;
elf = elf_begin(fd, ELF_C_READ , NULL);
h->argoffset = 0;
while((scn = elf_nextscn(elf, scn)) != 0)
{
char* why_skip = NULL;
gelf_getshdr(scn, &shdr);
char* name = elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name);
int addr = shdr.sh_addr << 2;
if (shdr.sh_size == 0) /* Skip empty sections */
why_skip = "(empty section)";
if (0==strcmp(name,".memBankMap")) {
why_skip = "(not needed)";
}
if (0==strcmp(name,".shstrtab")) {
why_skip = "(not needed)";
}
if (shdr.sh_type == SHT_NOBITS) {
why_skip = "(nobits)";
memset(&h->imem[addr], 0x0, shdr.sh_size);
}
if (0==strcmp(name,".bss")) {
why_skip = "(cleansing)";
memset(&h->imem[addr], 0x0, shdr.sh_size);
}
dbg("%s section %s %s %ld bytes @ 0x%x\n",
why_skip ? "Skipping" : "Uploading",
name,
why_skip ? why_skip : "",
(unsigned long) shdr.sh_size,
addr );
size_t ret;
if (!why_skip) {
ret = fseek(rfd, shdr.sh_offset, SEEK_SET);
if (ret !=0 ) {
err("Seek failed, bad elf\n");
goto errclose;
}
dbg("read to %d size %ld\n", addr, (unsigned long) shdr.sh_size);
ret = fread(&h->imem[addr], 1, shdr.sh_size, rfd);
if (ret != shdr.sh_size ) {
err("Ooops, failed to read all data: want %ld got %zd\n",
(unsigned long) shdr.sh_size, ret);
perror("fread");
goto errclose;
}
}
/* Now call the section filter chain */
struct easynmc_section_filter *f = h->sfilters;
int handled = 0;
while (!handled && f) {
dbg("Aplying section filter %s\n", f->name);
handled = f->handle_section(h, name, rfd, shdr);
f = f->next;
}
}
close(fd);
fclose(rfd);
dbg("Elvish loading done!\n");
return 0;
errclose:
close(fd);
errfclose:
fclose(rfd);
return -1;
}
internal_function
__libdwfl_getsym (Dwfl_Module *mod, int ndx, GElf_Sym *sym, GElf_Addr *addr,
GElf_Word *shndxp, Elf **elfp, Dwarf_Addr *biasp,
bool *resolved, bool adjust_st_value)
{
if (unlikely (mod == NULL))
return NULL;
if (unlikely (mod->symdata == NULL))
{
int result = INTUSE(dwfl_module_getsymtab) (mod);
if (result < 0)
return NULL;
}
/* All local symbols should come before all global symbols. If we
have an auxiliary table make sure all the main locals come first,
then all aux locals, then all main globals and finally all aux globals.
And skip the auxiliary table zero undefined entry. */
GElf_Word shndx;
int tndx = ndx;
int skip_aux_zero = (mod->syments > 0 && mod->aux_syments > 0) ? 1 : 0;
Elf *elf;
Elf_Data *symdata;
Elf_Data *symxndxdata;
Elf_Data *symstrdata;
if (mod->aux_symdata == NULL
|| ndx < mod->first_global)
{
/* main symbol table (locals). */
tndx = ndx;
elf = mod->symfile->elf;
symdata = mod->symdata;
symxndxdata = mod->symxndxdata;
symstrdata = mod->symstrdata;
}
else if (ndx < mod->first_global + mod->aux_first_global - skip_aux_zero)
{
/* aux symbol table (locals). */
tndx = ndx - mod->first_global + skip_aux_zero;
elf = mod->aux_sym.elf;
symdata = mod->aux_symdata;
symxndxdata = mod->aux_symxndxdata;
symstrdata = mod->aux_symstrdata;
}
else if ((size_t) ndx < mod->syments + mod->aux_first_global - skip_aux_zero)
{
/* main symbol table (globals). */
tndx = ndx - mod->aux_first_global + skip_aux_zero;
elf = mod->symfile->elf;
symdata = mod->symdata;
symxndxdata = mod->symxndxdata;
symstrdata = mod->symstrdata;
}
else
{
/* aux symbol table (globals). */
tndx = ndx - mod->syments + skip_aux_zero;
elf = mod->aux_sym.elf;
symdata = mod->aux_symdata;
symxndxdata = mod->aux_symxndxdata;
symstrdata = mod->aux_symstrdata;
}
sym = gelf_getsymshndx (symdata, symxndxdata, tndx, sym, &shndx);
if (unlikely (sym == NULL))
{
__libdwfl_seterrno (DWFL_E_LIBELF);
return NULL;
}
if (sym->st_shndx != SHN_XINDEX)
shndx = sym->st_shndx;
/* Figure out whether this symbol points into an SHF_ALLOC section. */
bool alloc = true;
if ((shndxp != NULL || mod->e_type != ET_REL)
&& (sym->st_shndx == SHN_XINDEX
|| (sym->st_shndx < SHN_LORESERVE && sym->st_shndx != SHN_UNDEF)))
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (elf_getscn (elf, shndx), &shdr_mem);
alloc = unlikely (shdr == NULL) || (shdr->sh_flags & SHF_ALLOC);
}
/* In case of an value in an allocated section the main Elf Ebl
might know where the real value is (e.g. for function
descriptors). */
char *ident;
GElf_Addr st_value = sym->st_value & ebl_func_addr_mask (mod->ebl);
*resolved = false;
if (! adjust_st_value && mod->e_type != ET_REL && alloc
&& (GELF_ST_TYPE (sym->st_info) == STT_FUNC
|| (GELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
&& (ident = elf_getident (elf, NULL)) != NULL
&& ident[EI_OSABI] == ELFOSABI_LINUX)))
{
if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR))
{
if (elf != mod->main.elf)
{
st_value = dwfl_adjusted_st_value (mod, elf, st_value);
st_value = dwfl_deadjust_st_value (mod, mod->main.elf, st_value);
}
*resolved = ebl_resolve_sym_value (mod->ebl, &st_value);
if (! *resolved)
st_value = sym->st_value;
}
}
if (shndxp != NULL)
/* Yield -1 in case of a non-SHF_ALLOC section. */
*shndxp = alloc ? shndx : (GElf_Word) -1;
switch (sym->st_shndx)
{
case SHN_ABS: /* XXX sometimes should use bias?? */
case SHN_UNDEF:
case SHN_COMMON:
break;
default:
if (mod->e_type == ET_REL)
{
/* In an ET_REL file, the symbol table values are relative
to the section, not to the module's load base. */
size_t symshstrndx = SHN_UNDEF;
Dwfl_Error result = __libdwfl_relocate_value (mod, elf,
&symshstrndx,
shndx, &st_value);
if (unlikely (result != DWFL_E_NOERROR))
{
__libdwfl_seterrno (result);
return NULL;
}
}
else if (alloc)
/* Apply the bias to the symbol value. */
st_value = dwfl_adjusted_st_value (mod,
*resolved ? mod->main.elf : elf,
st_value);
break;
}
if (adjust_st_value)
sym->st_value = st_value;
if (addr != NULL)
*addr = st_value;
if (unlikely (sym->st_name >= symstrdata->d_size))
{
__libdwfl_seterrno (DWFL_E_BADSTROFF);
return NULL;
}
if (elfp)
*elfp = elf;
if (biasp)
*biasp = dwfl_adjusted_st_value (mod, elf, 0);
return (const char *) symstrdata->d_buf + sym->st_name;
}
