int find_symbol(char *fn, struct lsym *lsym, unsigned long baseaddr)
{
struct lsym *ls;
int num = 0;
for (ls = lsym; ls->name; ls++)
num++;
elf_version(EV_CURRENT);
int fd = open(fn, O_RDONLY);
if (fd < 0)
return -1;
long ret = -1;
Elf *elf = elf_begin(fd, ELF_C_READ, NULL);
if (elf == NULL)
goto out;
GElf_Ehdr header;
if (!gelf_getehdr(elf, &header))
goto out_elf;
Elf_Scn *section = NULL;
int found = 0;
while (found < num && (section = elf_nextscn(elf, section)) != 0) {
GElf_Shdr shdr, *sh;
sh = gelf_getshdr(section, &shdr);
if (sh->sh_type == SHT_SYMTAB || sh->sh_type == SHT_DYNSYM) {
Elf_Data *data = elf_getdata(section, NULL);
GElf_Sym *sym, symbol;
int j;
unsigned numsym = sh->sh_size / sh->sh_entsize;
for (j = 0; j < numsym; j++) {
sym = gelf_getsymshndx(data, NULL, j, &symbol, NULL);
char *symname = elf_strptr(elf, shdr.sh_link, sym->st_name);
for (ls = lsym; ls->name; ls++) {
if (!strcmp(symname, ls->name)) {
Elf_Scn *oscn = elf_getscn(elf, sym->st_shndx);
GElf_Shdr oshdr, *osh;
osh = gelf_getshdr(oscn, &oshdr);
ls->addr = (sym->st_value - osh->sh_addr) + osh->sh_offset + baseaddr;
found++;
if (found == num)
break;
}
}
}
}
}
if (found == num)
ret = 0;
out_elf:
elf_end(elf);
out:
close(fd);
return ret;
}
std::string get_embedded_repo() {
GElf_Shdr shdr;
size_t shstrndx;
char *name;
Elf_Scn *scn;
if (elf_version(EV_CURRENT) == EV_NONE) return "";
int fd = open("/proc/self/exe", O_RDONLY, 0);
if (fd < 0) return "";
Elf* e = elf_begin(fd, ELF_C_READ, nullptr);
if (!e ||
elf_kind(e) != ELF_K_ELF ||
!elf_getshstrndx(e, &shstrndx)) {
return "";
}
scn = nullptr;
while ((scn = elf_nextscn(e, scn)) != nullptr) {
if (gelf_getshdr(scn, &shdr) != &shdr ||
!(name = elf_strptr(e, shstrndx , shdr.sh_name))) {
return "";
}
if (!strcmp("repo", name)) {
GElf_Shdr ghdr;
if (gelf_getshdr(scn, &ghdr) != &ghdr) return "";
char buf[512];
sprintf(buf, "/proc/self/exe:%lu:%lu", ghdr.sh_offset, ghdr.sh_size);
sqlite3_embedded_initialize(nullptr, true);
return buf;
}
}
return "";
}
Elf_Scn *elf_utils_new_scn_with_name(Elf *e, const char *scn_name)
{
Elf_Scn *scn;
GElf_Shdr shdr;
size_t shstrndx, index, namelen;
Elf_Data *shstrdata;
void *ptr;
ELF_ASSERT(elf_getshdrstrndx(e, &shstrndx) == 0);
ELF_ASSERT(scn = elf_getscn(e, shstrndx));
ELF_ASSERT(shstrdata = elf_getdata(scn, NULL));
namelen = strlen(scn_name) + 1;
ELF_ASSERT(gelf_getshdr(scn, &shdr));
if (!elf_utils_shift_contents(e, shdr.sh_offset + shdr.sh_size, namelen))
goto failure;
ASSERT(ptr = realloc(shstrdata->d_buf, shstrdata->d_size + namelen));
index = shstrdata->d_size;
strcpy(ptr+index, scn_name);
shstrdata->d_buf = ptr;
shstrdata->d_size += namelen;
shdr.sh_size += namelen;
ELF_ASSERT(gelf_update_shdr(scn, &shdr));
ELF_ASSERT(scn = elf_newscn(e));
ELF_ASSERT(gelf_getshdr(scn, &shdr));
shdr.sh_name = index;
ELF_ASSERT(gelf_update_shdr(scn, &shdr));
return scn;
failure:
return NULL;
}
static int init_scns()
{
Elf* e = g.e;
size_t shstrndx = g.shstrndx;
size_t shdrnum = g.shdrnum;
int i = 0;
GElf_Shdr shdr;
Elf_Scn** buf = (Elf_Scn**)malloc(shdrnum * sizeof(Elf_Scn*));
GElf_Shdr* buf2 = (GElf_Shdr*)malloc(shdrnum * sizeof(GElf_Shdr));
if (buf == NULL) {
errx (EXIT_FAILURE , "malloc failed");
return -1;
}
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL && i < shdrnum) {
if (gelf_getshdr (scn , & shdr ) != & shdr) {
errx ( EXIT_FAILURE , " getshdr () failed : %s.",
elf_errmsg ( -1));
free(buf);
return -1;
}
buf[i] = scn;
buf2[i] = shdr;
i++;
}
if (i < shdrnum) {
/* the .shstrtab section*/
/* size_t shstrndx; */
/* if (elf_getshdrstrndx (e, &shstrndx) != 0) */
/* errx (EXIT_FAILURE, " getshdrstrndx () failed : %s.", */
/* elf_errmsg (-1)); */
if ((scn = elf_getscn (e, shstrndx)) == NULL )
errx ( EXIT_FAILURE , " getscn () failed : %s.",
elf_errmsg ( -1));
if (gelf_getshdr(scn , &shdr) != & shdr )
errx ( EXIT_FAILURE , " getshdr ( shstrndx ) failed : %s.",
elf_errmsg ( -1));
buf[i] = scn;
buf2[i] = shdr;
}
// printf("[D] No. of sections:%d\n", i-1);
g.scns = buf;
g.shdrs = buf2;
return 0;
}
int ELF_build_symtbl(PROC_SYMTBL* symtbl){
uint32_t sym_num;
Elf32_Sym * sym;
int strtab_index = 0;
scn = NULL;
data = NULL;
while((scn = elf_nextscn(e, scn)) != NULL){
if(gelf_getshdr(scn, &shdr) != &shdr){
fprintf(stderr, "getshdr() failed.\n");
exit(1);
}
strtab_index ++;
char* name = elf_strptr(e, ehdr.e_shstrndx, shdr.sh_name);
if(strcmp(name, ".strtab")==0)
break;
}
scn = NULL;
while((scn = elf_nextscn(e, scn)) != NULL){
if(gelf_getshdr(scn, &shdr) != &shdr){
fprintf(stderr, "getshdr() failed.\n");
exit(1);
}
char* name = elf_strptr(e, ehdr.e_shstrndx, shdr.sh_name);
if(strcmp(name, ".symtab")==0){
data = elf_getdata(scn, data);
sym_num = data->d_size/sizeof(Elf32_Sym);
symtbl->sym_num = sym_num;
// initial symtbl->name
symtbl->name = malloc(sizeof(char*) * sym_num);
int i;
for(i=0; i<sym_num; i++)
(symtbl->name)[i] = malloc(sizeof(char) * 100);
// initial symtbl addr
symtbl->addr = malloc(sizeof(uint32_t) * sym_num);
// initial symtbl st_info
symtbl->st_info = malloc(sizeof(unsigned char) * sym_num);
sym = (Elf32_Sym*)data->d_buf;
for(i=0; i<sym_num; i++){
name = elf_strptr(e, strtab_index, sym[i].st_name);
strcpy(symtbl->name[i], name);
symtbl->addr[i] = sym[i].st_value;
symtbl->st_info[i] = sym[i].st_info;
}
}
}
return 1;
}
static void handle_dynamic_section(elf_info_s *elf, Elf_Scn *scn, GElf_Shdr shdr)
{
Elf_Data *data;
GElf_Addr replt_addr;
size_t replt_count;
/* get data of .dynamic */
data = elf_getdata(scn, NULL);
/* iterate through .dynamic */
for (size_t i = 0; i < shdr.sh_size / shdr.sh_entsize; ++i) {
GElf_Dyn dyn;
// get entries i
gelf_getdyn(data, i, &dyn);
// if replt
if (dyn.d_tag == DT_JMPREL)
replt_addr = dyn.d_un.d_ptr;
// if replt_size
if (dyn.d_tag == DT_PLTRELSZ)
replt_count = dyn.d_un.d_val;
}
LOG(INFO, "Section relplt at 0x%lx (%zu)", replt_addr, replt_count);
for (size_t i = 1; i < elf->hdr.e_shnum; ++i) {
Elf_Scn *scn;
GElf_Shdr shdr;
scn = elf_getscn(elf->elf, i);
gelf_getshdr(scn, &shdr);
if (shdr.sh_addr == replt_addr && shdr.sh_size == replt_count) {
elf->replt = elf_getdata(scn, NULL);
elf->replt_count = shdr.sh_size / shdr.sh_entsize;
break;
}
}
}
static elf_info_s *elf_symbols(int fd)
{
/* Open Elf */
elf_version(EV_CURRENT);
elf_info_s *elf = calloc(1, sizeof (elf_info_s));
elf->elf = elf_begin(fd, ELF_C_READ, NULL);
gelf_getehdr(elf->elf, &elf->hdr);
/* Iterate through the sections */
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn(elf->elf, scn)) != 0) {
GElf_Shdr shdr;
const char *name;
/* get section header */
gelf_getshdr(scn, &shdr);
/* get section name */
name = elf_strptr(elf->elf, elf->hdr.e_shstrndx, shdr.sh_name);
//LOG(INFO, "Iter on %s", name);
if (shdr.sh_type == SHT_DYNSYM)
handle_dynsym_section(elf, scn, shdr);
else if (shdr.sh_type == SHT_DYNAMIC)
handle_dynamic_section(elf, scn, shdr);
else if ((shdr.sh_type == SHT_PROGBITS || shdr.sh_type == SHT_NOBITS)
&& !strcmp(name, ".plt"))
handle_plt_section(elf, shdr);
else if (!strcmp(name, ".got.plt"))
handle_gotplt_section(elf, shdr);
}
return elf;
}
/* Below code adapted from libelf tutorial example */
static u32 extract_functions_internal (const char *str, func_entry *func_list) {
Elf *e;
Elf_Kind ek;
Elf_Scn *scn;
Elf_Data *edata;
u32 fd, i, symbol_count;
GElf_Sym sym;
GElf_Shdr shdr;
u32 func_count = 0;
if(elf_version(EV_CURRENT) == EV_NONE) {
printf("Error initializing ELF: %s\n", elf_errmsg(-1));
return -1;
}
if ((fd = open(str, O_RDONLY, 0)) < 0) {
printf("Unable to open %s\n", str);
return -1;
}
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
printf("elf_begin failed: %s\n", elf_errmsg(-1));
}
ek = elf_kind(e);
if(ek != ELF_K_ELF) {
printf("not an ELF object");
} else {
scn = NULL;
edata = NULL;
while((scn = elf_nextscn(e, scn)) != NULL) {
gelf_getshdr(scn, &shdr);
if(shdr.sh_type == SHT_SYMTAB) {
edata = elf_getdata(scn, edata);
symbol_count = shdr.sh_size / shdr.sh_entsize;
for(i = 0; i < symbol_count; i++) {
gelf_getsym(edata, i, &sym);
if(ELF32_ST_TYPE(sym.st_info) != STT_FUNC) {
check_for_end_marker(elf_strptr(e, shdr.sh_link, sym.st_name), sym.st_value);
continue;
}
if(sym.st_size == 0) continue;
func_list[func_count].offset = sym.st_value;
func_list[func_count++].func_name = strdup(elf_strptr(e, shdr.sh_link, sym.st_name));
if(func_count >= MAXFNS) {
printf("Func limit (%"PRId32") reached, please increase MAXFNS & rebuild\n", MAXFNS);
raise(SIGABRT);
}
// printf("%08x %08x\t%s\n", sym.st_value, sym.st_size, elf_strptr(e, shdr.sh_link, sym.st_name));
}
}
}
}
elf_end(e);
close(fd);
return func_count;
}
/* Check if Symbol
Table
exists */
static _Bool check_symbol_table(void)
{
Elf_Scn *section = 0;
int number = 0;
while ((section = elf_nextscn(elf, section)) != 0) {
char *name = 0;
if (gelf_getshdr (section, &symtab_shdr) != 0) {
if (symtab_shdr.sh_type == SHT_SYMTAB) {
/* Change SHT_SYMTAB to SHT_DYNSYM
* to access the dynamic symbol table
*/
printf("Found Symbol Table\n");
symtab_section = section;
/* You can use the function given below to pri nt
* out the symbol table
* print_symbols(elf, section, shdr);
*/
return TRUE;
}
}
}
/* no symtab */
printf("No symbol table found.\n");
return FALSE;
}
int
findelfsecidx(Elf *elf, const char *file, const char *tofind)
{
Elf_Scn *scn = NULL;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
if (gelf_getehdr(elf, &ehdr) == NULL)
elfterminate(file, "Couldn't read ehdr");
while ((scn = elf_nextscn(elf, scn)) != NULL) {
char *name;
if (gelf_getshdr(scn, &shdr) == NULL) {
elfterminate(file,
"Couldn't read header for section %d",
elf_ndxscn(scn));
}
if ((name = elf_strptr(elf, ehdr.e_shstrndx,
(size_t)shdr.sh_name)) == NULL) {
elfterminate(file,
"Couldn't get name for section %d",
elf_ndxscn(scn));
}
if (strcmp(name, tofind) == 0)
return (elf_ndxscn(scn));
}
return (-1);
}
int
find_injected_secaddr(elf_data_t *elf, inject_data_t *inject)
{
Elf_Scn *scn;
GElf_Shdr shdr;
uint64_t max_inject_addr = 0;
char* s;
size_t shstrndx;
if(elf_getshdrstrndx(elf->e, &shstrndx) < 0) {
return -1;
}
scn = NULL;
while((scn = elf_nextscn(elf->e, scn))) {
if(!gelf_getshdr(scn, &shdr)) {
return -1;
}
s = elf_strptr(elf->e, shstrndx, shdr.sh_name);
if(!s) {
return -1;
}
if(!strcmp(s, DYNINST_NAME))
fprintf(finfo,"dyninst end=%lx\n",shdr.sh_addr + shdr.sh_size);
if (shdr.sh_addr + shdr.sh_offset > max_inject_addr)
max_inject_addr = shdr.sh_addr + shdr.sh_size;
}
inject->secaddr = max_inject_addr + inject->len + 0x4000;
return 0;
}
int
elf_getphnum(Elf *elf, size_t *phnum)
{
GElf_Ehdr ehdr;
Elf_Scn *scn;
GElf_Shdr shdr0;
if (gelf_getehdr(elf, &ehdr) == NULL)
return (0);
if (ehdr.e_phnum != PN_XNUM) {
*phnum = ehdr.e_phnum;
return (1);
}
if ((scn = elf_getscn(elf, 0)) == NULL ||
gelf_getshdr(scn, &shdr0) == NULL)
return (0);
if (shdr0.sh_info == 0)
*phnum = ehdr.e_phnum;
else
*phnum = shdr0.sh_info;
return (1);
}
Elf_Scn *elf_utils_new_scn_with_data(Elf *e, const char *scn_name, void *buf, int len)
{
Elf_Scn *scn;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf_Data *data;
int offset;
scn = elf_utils_new_scn_with_name(e, scn_name);
if (scn == NULL)
goto failure;
ELF_ASSERT(gelf_getehdr(e, &ehdr));
offset = ehdr.e_shoff;
if (!elf_utils_shift_contents(e, offset, len))
goto failure;
ELF_ASSERT(gelf_getshdr(scn, &shdr));
shdr.sh_offset = offset;
shdr.sh_size = len;
shdr.sh_addralign = 1;
ELF_ASSERT(gelf_update_shdr(scn, &shdr));
ELF_ASSERT(data = elf_newdata(scn));
data->d_buf = buf;
data->d_type = ELF_T_BYTE;
data->d_version = EV_CURRENT;
data->d_size = len;
data->d_off = 0;
data->d_align = 1;
return scn;
failure:
return NULL;
}
/**
* @brief Search a single, particular ELF symbol table for a named symbol
*
* @param elf The open ELF object
* @param symtab The ELF symbol table section
* @param name The symbol name to find
*
* @returns The address to which the symbol points, 0 otherwise.
*/
static GElf_Addr elf_scn_getsymaddr_byname(Elf *elf, Elf_Scn *symtab,
const char * name) {
GElf_Shdr shdr;
Elf_Data *data;
uint32_t syms, i;
GElf_Sym sym;
if (gelf_getshdr(symtab, &shdr) == NULL || shdr.sh_type != SHT_SYMTAB) {
return 0;
}
data = elf_getdata(symtab, NULL);
if (data == NULL) {
return 0;
}
syms = shdr.sh_size / shdr.sh_entsize;
for(i=0; i<syms; i++) {
gelf_getsym(data, i, &sym);
if (strcmp(elf_strptr(elf, shdr.sh_link, sym.st_name), name) == 0) {
return sym.st_value;
}
}
return 0;
}
/**
* @brief Search an elf for a named section
*
* @param elf The open elf object
* @param name The section name to find
*
* @returns A pointer to the section if successful, NULL otherwise.
*/
static Elf_Scn * elf_getscn_byname(Elf *elf, const char * name) {
Elf_Scn *scn = NULL;
size_t shstrndx;
GElf_Shdr shdr;
char *section_name;
if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
fprintf(stderr, "elf_getshdrstrndx() failed: %s\n", elf_errmsg(-1));
} else {
/**
* Iterate over the sections in the ELF descriptor to get the indices
* of the .text and .data descriptors
*/
while ((scn = elf_nextscn(elf, scn)) != NULL) {
if (gelf_getshdr(scn, &shdr) != &shdr) {
fprintf(stderr, "getshdr() failed: %s\n",
elf_errmsg(-1));
} else {
section_name = elf_strptr(elf, shstrndx, shdr.sh_name);
if (section_name == NULL) {
fprintf(stderr, "elf_strptr() failed: %s\n",
elf_errmsg(-1));
} else if (strcmp(section_name, name) == 0) {
break;
}
}
}
}
return scn;
}
static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
GElf_Shdr *shp, const char *name,
size_t *idx)
{
Elf_Scn *sec = NULL;
size_t cnt = 1;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
return NULL;
while ((sec = elf_nextscn(elf, sec)) != NULL) {
char *str;
gelf_getshdr(sec, shp);
str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
if (!strcmp(name, str)) {
if (idx)
*idx = cnt;
break;
}
++cnt;
}
return sec;
}
int
rewrite_section_name(elf_data_t *elf, inject_data_t *inject, char **err)
{
Elf_Scn *scn;
GElf_Shdr shdr;
char *s;
size_t shstrndx, stroff, strbase;
if(strlen(inject->secname) > strlen(ABITAG_NAME)) {
(*err) = "section name too long";
return -1;
}
if(elf_getshdrstrndx(elf->e, &shstrndx) < 0) {
(*err) = "failed to get string table section index";
return -1;
}
stroff = 0;
strbase = 0;
scn = NULL;
while((scn = elf_nextscn(elf->e, scn))) {
if(!gelf_getshdr(scn, &shdr)) {
(*err) = "failed to get section header";
return -1;
}
s = elf_strptr(elf->e, shstrndx, shdr.sh_name);
if(!s) {
(*err) = "failed to get section name";
return -1;
}
if(!strcmp(s, ABITAG_NAME)) {
stroff = shdr.sh_name; /* offset into shstrtab */
} else if(!strcmp(s, SHSTRTAB_NAME)) {
strbase = shdr.sh_offset; /* offset to start of shstrtab */
}
}
if(stroff == 0) {
(*err) = "cannot find shstrtab entry for injected section";
return -1;
} else if(strbase == 0) {
(*err) = "cannot find shstrtab";
return -1;
}
inject->shstroff = strbase + stroff;
verbose("renaming rewritten section to \"%s\"", inject->secname);
verbose("writing section string table to file");
if(write_secname(elf, inject, err) < 0) {
return -1;
}
return 0;
}
/* 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:
if (shdr->sh_entsize == 0)
break;
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. */
if (shdr->sh_entsize == 0)
break;
*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;
}
bool
addr_in_section (Elf *elf, GElf_Word shndx, GElf_Addr addr)
{
GElf_Shdr shdr;
Elf_Scn *scn = elf_getscn (elf, shndx);
gelf_getshdr (scn, &shdr);
return addr >= shdr.sh_addr && addr < shdr.sh_addr + shdr.sh_size;
}
/**
* Finds a section by its name in an ELF file.
* @param elf
* A libelf handle representing the file.
* @param section_name
* Name of section to be found.
* @param data_dest
* Save the resulting elf data pointer here. Cannot be NULL.
* @param shdr_dest
* Save the section header here. Cannot be NULL.
* @param error_message
* Will be filled by an error message if the function fails (returns
* zero). Caller is responsible for calling free() on the string
* pointer. If function succeeds, the pointer is not touched by the
* function.
* @returns
* Zero on error, index of the section on success.
*/
static unsigned
find_elf_section_by_name(Elf *elf,
const char *section_name,
Elf_Data **data_dest,
GElf_Shdr *shdr_dest,
char **error_message)
{
/* Find the string table index */
size_t shdr_string_index;
if (0 != elf_getshdrstrndx(elf, &shdr_string_index))
{
*error_message = sr_asprintf("elf_getshdrstrndx failed");
return 0;
}
unsigned section_index = 0;
Elf_Scn *section = NULL;
while ((section = elf_nextscn(elf, section)) != NULL)
{
/* Starting index is 1. */
++section_index;
GElf_Shdr shdr;
if (gelf_getshdr(section, &shdr) != &shdr)
{
*error_message = sr_asprintf("gelf_getshdr failed");
return 0;
}
const char *current_section_name = elf_strptr(elf,
shdr_string_index,
shdr.sh_name);
if (!current_section_name)
{
*error_message = sr_asprintf("elf_strptr failed");
return 0;
}
if (0 == strcmp(current_section_name, section_name))
{
/* We found the right section! Save the data. */
*data_dest = elf_getdata(section, NULL);
if (!*data_dest)
{
*error_message = sr_asprintf("elf_getdata failed");
return 0;
}
/* Save the section header. */
*shdr_dest = shdr;
return section_index;
}
}
*error_message = sr_asprintf("Section %s not found", section_name);
return 0;
}
static void
find_section_base(const char *exe, Elf *e, const char *section)
{
Dwarf_Addr off;
Elf_Scn *scn;
GElf_Ehdr eh;
GElf_Shdr sh;
size_t shstrndx;
int elferr;
const char *name;
if (gelf_getehdr(e, &eh) != &eh) {
warnx("gelf_getehdr failed: %s", elf_errmsg(-1));
return;
}
if (!elf_getshstrndx(e, &shstrndx)) {
warnx("elf_getshstrndx failed: %s", elf_errmsg(-1));
return;
}
(void) elf_errno();
off = 0;
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
if (gelf_getshdr(scn, &sh) == NULL) {
warnx("gelf_getshdr failed: %s", elf_errmsg(-1));
continue;
}
if ((name = elf_strptr(e, shstrndx, sh.sh_name)) == NULL)
goto next;
if (!strcmp(section, name)) {
if (eh.e_type == ET_EXEC || eh.e_type == ET_DYN) {
/*
* For executables, section base is the virtual
* address of the specified section.
*/
section_base = sh.sh_addr;
} else if (eh.e_type == ET_REL) {
/*
* For relocatables, section base is the
* relative offset of the specified section
* to the start of the first section.
*/
section_base = off;
} else
warnx("unknown e_type %u", eh.e_type);
return;
}
next:
off += sh.sh_size;
}
elferr = elf_errno();
if (elferr != 0)
warnx("elf_nextscn failed: %s", elf_errmsg(elferr));
errx(EXIT_FAILURE, "%s: cannot find section %s", exe, section);
}
const char *get_scn_name(vita_elf_t *ve, Elf_Scn *scn)
{
size_t shstrndx;
GElf_Shdr shdr;
elf_getshdrstrndx(ve->elf, &shstrndx);
gelf_getshdr(scn, &shdr);
return elf_strptr(ve->elf, shstrndx, shdr.sh_name);
}
/*
* @param e elf handle
* @param name name of section to be found
* @param filename filename for logging messages
* @param dest save the resulting elf data pointer here (can be NULL)
* @param shdr_dest save the section header here (can be NULL)
* @returns zero on error, index of the section on success
*/
static unsigned xelf_section_by_name(Elf *e, const char *name, const char *filename, Elf_Data **dest, GElf_Shdr *shdr_dest)
{
Elf_Scn *scn = NULL;
GElf_Shdr shdr;
unsigned section_index = 0;
size_t shstrndx;
/* Find the string table index */
if (elf_getshdrstrndx(e, &shstrndx) != 0)
{
VERB1 log_elf_error("elf_getshdrstrndx", filename);
return 0;
}
while ((scn = elf_nextscn(e, scn)) != NULL)
{
section_index++; /* starting index is 1 */
if (gelf_getshdr(scn, &shdr) != &shdr)
{
VERB1 log_elf_error("gelf_getshdr", filename);
continue;
}
const char *scnname = elf_strptr(e, shstrndx, shdr.sh_name);
if (scnname == NULL)
{
VERB1 log_elf_error("elf_strptr", filename);
continue;
}
if (strcmp(scnname, name) == 0)
{
/* Found, save data */
if (dest)
{
*dest = elf_getdata(scn, NULL);
if (*dest == NULL)
{
VERB1 log_elf_error("elf_getdata", filename);
break;
}
}
/* save shdr */
if (shdr_dest)
{
*shdr_dest = shdr;
}
return section_index;
}
}
VERB1 log("Section %s not found in %s\n", name, filename);
return 0;
}
static void
check_section (Dwarf *result, GElf_Ehdr *ehdr, Elf_Scn *scn, bool inscngrp)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr;
/* Get the section header data. */
shdr = gelf_getshdr (scn, &shdr_mem);
if (shdr == NULL)
/* This should never happen. If it does something is
wrong in the libelf library. */
abort ();
/* Make sure the section is part of a section group only iff we
really need it. If we are looking for the global (= non-section
group debug info) we have to ignore all the info in section
groups. If we are looking into a section group we cannot look at
a section which isn't part of the section group. */
if (! inscngrp && (shdr->sh_flags & SHF_GROUP) != 0)
/* Ignore the section. */
return;
/* We recognize the DWARF section by their names. This is not very
safe and stable but the best we can do. */
const char *scnname = elf_strptr (result->elf, ehdr->e_shstrndx,
shdr->sh_name);
if (scnname == NULL)
{
/* The section name must be valid. Otherwise is the ELF file
invalid. */
__libdw_seterrno (DWARF_E_INVALID_ELF);
free (result);
return;
}
/* Recognize the various sections. Most names start with .debug_. */
size_t cnt;
for (cnt = 0; cnt < ndwarf_scnnames; ++cnt)
if (strcmp (scnname, dwarf_scnnames[cnt]) == 0)
{
/* Found it. Remember where the data is. */
if (unlikely (result->sectiondata[cnt] != NULL))
/* A section appears twice. That's bad. We ignore the section. */
break;
/* Get the section data. */
Elf_Data *data = elf_getdata (scn, NULL);
if (data != NULL && data->d_size != 0)
/* Yep, there is actually data available. */
result->sectiondata[cnt] = data;
break;
}
}
static void update_dyn_cache(ElfCreator *ctor)
{
ctor->dynscn = get_scn_by_type(ctor, SHT_DYNAMIC);
if (ctor->dynscn == NULL)
return;
ctor->dynshdr = gelf_getshdr(ctor->dynscn, &ctor->dynshdr_mem);
ctor->dyndata = elf_getdata(ctor->dynscn, NULL);
}
int
internal_function
__libdwfl_find_build_id (Dwfl_Module *mod, bool set, Elf *elf)
{
size_t shstrndx = SHN_UNDEF;
int result = 0;
Elf_Scn *scn = elf_nextscn (elf, NULL);
if (scn == NULL)
{
/* No sections, have to look for phdrs. */
GElf_Ehdr ehdr_mem;
GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
size_t phnum;
if (unlikely (ehdr == NULL)
|| unlikely (elf_getphdrnum (elf, &phnum) != 0))
{
__libdwfl_seterrno (DWFL_E_LIBELF);
return -1;
}
for (size_t i = 0; result == 0 && i < phnum; ++i)
{
GElf_Phdr phdr_mem;
GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
if (likely (phdr != NULL) && phdr->p_type == PT_NOTE)
result = check_notes (mod, set,
elf_getdata_rawchunk (elf,
phdr->p_offset,
phdr->p_filesz,
ELF_T_NHDR),
phdr->p_vaddr + mod->main.bias);
}
}
else
do
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE)
{
/* Determine the right sh_addr in this module. */
GElf_Addr vaddr = 0;
if (!(shdr->sh_flags & SHF_ALLOC))
vaddr = NO_VADDR;
else if (mod->e_type != ET_REL)
vaddr = shdr->sh_addr + mod->main.bias;
else if (__libdwfl_relocate_value (mod, elf, &shstrndx,
elf_ndxscn (scn), &vaddr))
vaddr = NO_VADDR;
result = check_notes (mod, set, elf_getdata (scn, NULL), vaddr);
}
}
while (result == 0 && (scn = elf_nextscn (elf, scn)) != NULL);
return result;
}
static void
set_flag(char *ifile, ulong_t flval)
{
Elf *elf;
Elf_Scn *scn;
Elf_Data *data;
GElf_Shdr shdr;
GElf_Dyn dyn;
int fd, secidx, nent, i;
(void) elf_version(EV_CURRENT);
if ((fd = open(ifile, O_RDWR)) < 0)
die("Can't open %s", ifile);
if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL)
elfdie("Can't start ELF for %s", ifile);
if ((secidx = findelfsecidx(elf, ".dynamic")) == -1)
die("Can't find .dynamic section in %s\n", ifile);
if ((scn = elf_getscn(elf, secidx)) == NULL)
elfdie("elf_getscn (%d)", secidx);
if (gelf_getshdr(scn, &shdr) == NULL)
elfdie("gelf_shdr");
if ((data = elf_getdata(scn, NULL)) == NULL)
elfdie("elf_getdata");
nent = shdr.sh_size / shdr.sh_entsize;
for (i = 0; i < nent; i++) {
if (gelf_getdyn(data, i, &dyn) == NULL)
elfdie("gelf_getdyn");
if (dyn.d_tag == DT_FLAGS_1) {
dyn.d_un.d_val |= (Elf64_Xword)flval;
if (gelf_update_dyn(data, i, &dyn) == 0)
elfdie("gelf_update_dyn");
break;
}
}
if (i == nent) {
die("%s's .dynamic section doesn't have a DT_FLAGS_1 "
"field\n", ifile);
}
if (elf_update(elf, ELF_C_WRITE) == -1)
elfdie("Couldn't update %s with changes", ifile);
(void) elf_end(elf);
(void) close(fd);
}
uint8_t *dump_section_data(Elf *elf_object, int *size)
{
uint8_t *buffer = NULL;
Elf_Data *data = NULL;
size_t shdr_num;
size_t max_saddr = 0;
GElf_Shdr shdr;
size_t shstrndx;
char *name = NULL;
*size = 0;
int ret = elf_getshdrnum(elf_object, &shdr_num);
if (ret) {
printf("Problem during ELF parsing\n");
return NULL;
}
if (shdr_num == 0)
return NULL;
Elf_Scn *cur_section = NULL;
ret = elf_getshdrstrndx(elf_object, &shstrndx);
if (ret)
printf("No string table found\n");
while ((cur_section = elf_nextscn(elf_object, cur_section)) != NULL ) {
if (gelf_getshdr(cur_section, &shdr) != &shdr) {
printf("Problem during ELF parsing\n");
return NULL;
}
if ((shdr.sh_type == SHT_PROGBITS) && (shdr.sh_flags & SHF_ALLOC) && shdr.sh_size != 0) {
name = elf_strptr(elf_object, shstrndx , shdr.sh_name);
printf("Loading section %s, size 0x%08X lma 0x%08X\n",
name ? name : "??", (unsigned int)shdr.sh_size, (unsigned int)shdr.sh_addr);
if (shdr.sh_addr + shdr.sh_size >= max_saddr) {
max_saddr = shdr.sh_addr + shdr.sh_size;
buffer = realloc(buffer, max_saddr);
}
data = elf_getdata(cur_section, data);
if (data != NULL)
memcpy(buffer + shdr.sh_addr, data->d_buf, data->d_size);
else {
printf("Couldn't load section data chunk\n");
return NULL;
}
}
}
*size = max_saddr;
return buffer;
}
static const char *
elf_section_name (Elf *elf, GElf_Word shndx)
{
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf_Scn *scn = elf_getscn (elf, shndx);
gelf_getshdr (scn, &shdr);
gelf_getehdr (elf, &ehdr);
return elf_strptr (elf, ehdr.e_shstrndx, shdr.sh_name);
}
/*
* Print the symbol table. This function does not print the contents
* of the symbol table but sets up the parameters and then calls
* print_symtab to print the symbols. This function does not assume
* that there is only one section of type SYMTAB. Input is an opened
* ELF file, a pointer to the ELF header, and the filename.
*/
static void
get_symtab(Elf *elf_file, char *filename)
{
Elf_Scn *scn, *scnfd;
Elf_Data *data;
GElf_Word symtabtype;
size_t shstrndx;
if (elf_getshdrstrndx(elf_file, &shstrndx) == -1) {
(void) fprintf(stderr, gettext(
"%s: %s: cannot get e_shstrndx\n"),
prog_name, filename);
return;
}
/* get section header string table */
scnfd = get_scnfd(elf_file, shstrndx, SHT_STRTAB);
if (scnfd == NULL) {
(void) fprintf(stderr, gettext(
"%s: %s: cannot get string table\n"),
prog_name, filename);
return;
}
data = elf_getdata(scnfd, NULL);
if (data->d_size == 0) {
(void) fprintf(stderr, gettext(
"%s: %s: no data in string table\n"),
prog_name, filename);
return;
}
if (D_flag)
symtabtype = SHT_DYNSYM;
else if (L_flag)
symtabtype = SHT_SUNW_LDYNSYM;
else
symtabtype = SHT_SYMTAB;
scn = 0;
while ((scn = elf_nextscn(elf_file, scn)) != 0) {
GElf_Shdr shdr;
if (gelf_getshdr(scn, &shdr) == NULL) {
(void) fprintf(stderr, "%s: %s: %s:\n",
prog_name, filename, elf_errmsg(-1));
return;
}
if (shdr.sh_type == symtabtype) {
print_symtab(elf_file, shstrndx, scn,
&shdr, filename);
}
} /* end while */
}
