int elf_utils_shift_contents(Elf *e, int start_offset, int shift_amount)
{
GElf_Ehdr ehdr;
Elf_Scn *scn;
GElf_Shdr shdr;
size_t segment_count = 0, segndx;
GElf_Phdr phdr;
int bottom_section_offset = 0;
ELF_ASSERT(gelf_getehdr(e, &ehdr));
if (ehdr.e_shoff >= start_offset) {
ehdr.e_shoff += shift_amount;
ELF_ASSERT(gelf_update_ehdr(e, &ehdr));
}
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
ELF_ASSERT(gelf_getshdr(scn, &shdr));
if (shdr.sh_offset >= start_offset) {
shdr.sh_offset += shift_amount;
ELF_ASSERT(gelf_update_shdr(scn, &shdr));
}
if (shdr.sh_offset + shdr.sh_size > bottom_section_offset) {
bottom_section_offset = shdr.sh_offset + shdr.sh_size;
}
}
if (bottom_section_offset > ehdr.e_shoff) {
ELF_ASSERT(gelf_getehdr(e, &ehdr));
ehdr.e_shoff = bottom_section_offset;
ELF_ASSERT(gelf_update_ehdr(e, &ehdr));
}
/* A bug in libelf means that getphdrnum will report failure in a new file.
* However, it will still set segment_count, so we'll use it. */
ELF_ASSERT((elf_getphdrnum(e, &segment_count), segment_count > 0));
for (segndx = 0; segndx < segment_count; segndx++) {
ELF_ASSERT(gelf_getphdr(e, segndx, &phdr));
if (phdr.p_offset >= start_offset) {
phdr.p_offset += shift_amount;
ELF_ASSERT(gelf_update_phdr(e, segndx, &phdr));
}
}
return 1;
failure:
return 0;
}
ElfCreator *elfcreator_begin(char *path, Elf *elf) {
ElfCreator *ctor = NULL;
GElf_Ehdr ehdr_mem, *ehdr;
GElf_Half machine;
if (!(ctor = calloc(1, sizeof(*ctor))))
return NULL;
clear(ctor, 0);
ctor->path = path;
ctor->oldelf = elf;
ehdr = gelf_getehdr(elf, &ehdr_mem);
machine = ehdr->e_machine;
if ((ctor->fd = open(path, O_RDWR|O_CREAT|O_TRUNC, 0755)) < 0) {
err:
clear(ctor, 1);
free(ctor);
return NULL;
}
if (!(ctor->elf = elf_begin(ctor->fd, ELF_C_WRITE_MMAP, elf)))
goto err;
gelf_newehdr(ctor->elf, gelf_getclass(elf));
gelf_update_ehdr(ctor->elf, ehdr);
if (!(ctor->ehdr = gelf_getehdr(ctor->elf, &ctor->ehdr_mem)))
goto err;
return ctor;
}
static AsmCtx_t *
prepare_binary_output (AsmCtx_t *result, int machine, int klass, int data)
{
GElf_Ehdr *ehdr;
GElf_Ehdr ehdr_mem;
/* Create the ELF descriptor for the file. */
result->out.elf = elf_begin (result->fd, ELF_C_WRITE_MMAP, NULL);
if (result->out.elf == NULL)
{
err_libelf:
unlink (result->tmp_fname);
close (result->fd);
free (result);
__libasm_seterrno (ASM_E_LIBELF);
return NULL;
}
/* Create the ELF header for the output file. */
if (gelf_newehdr (result->out.elf, klass) == 0)
goto err_libelf;
ehdr = gelf_getehdr (result->out.elf, &ehdr_mem);
/* If this failed we are in trouble. */
assert (ehdr != NULL);
/* We create an object file. */
ehdr->e_type = ET_REL;
/* Set the ELF version. */
ehdr->e_version = EV_CURRENT;
/* Use the machine value the user provided. */
ehdr->e_machine = machine;
/* Same for the class and endianness. */
ehdr->e_ident[EI_CLASS] = klass;
ehdr->e_ident[EI_DATA] = data;
memcpy (&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG);
/* Write the ELF header information back. */
(void) gelf_update_ehdr (result->out.elf, ehdr);
/* No section so far. */
result->section_list = NULL;
/* Initialize the hash table. */
asm_symbol_tab_init (&result->symbol_tab, 67);
result->nsymbol_tab = 0;
/* And the string tables. */
result->section_strtab = ebl_strtabinit (true);
result->symbol_strtab = ebl_strtabinit (true);
/* We have no section groups so far. */
result->groups = NULL;
result->ngroups = 0;
return result;
}
int elf_utils_copy(Elf *dest, Elf *source)
{
GElf_Ehdr ehdr;
Elf_Scn *dst_scn, *src_scn;
GElf_Shdr shdr;
Elf_Data *dst_data, *src_data;
size_t segment_count, segndx;
GElf_Phdr phdr;
ELF_ASSERT(elf_flagelf(dest, ELF_C_SET, ELF_F_LAYOUT));
ELF_ASSERT(gelf_getehdr(source, &ehdr));
ELF_ASSERT(gelf_newehdr(dest, gelf_getclass(source)));
ELF_ASSERT(gelf_update_ehdr(dest, &ehdr));
src_scn = NULL;
while ((src_scn = elf_nextscn(source, src_scn)) != NULL) {
ELF_ASSERT(gelf_getshdr(src_scn, &shdr));
ELF_ASSERT(dst_scn = elf_newscn(dest));
ELF_ASSERT(gelf_update_shdr(dst_scn, &shdr));
src_data = NULL;
while ((src_data = elf_getdata(src_scn, src_data)) != NULL) {
ELF_ASSERT(dst_data = elf_newdata(dst_scn));
memcpy(dst_data, src_data, sizeof(Elf_Data));
}
}
ELF_ASSERT(elf_getphdrnum(source, &segment_count) == 0);
ELF_ASSERT(gelf_newphdr(dest, segment_count));
for (segndx = 0; segndx < segment_count; segndx++) {
ELF_ASSERT(gelf_getphdr(source, segndx, &phdr));
ELF_ASSERT(gelf_update_phdr(dest, segndx, &phdr));
}
return 1;
failure:
return 0;
}
int
write_ehdr(elf_data_t *elf, char **err)
{
off_t off;
size_t n, ehdr_size;
void *ehdr_buf;
if(!gelf_update_ehdr(elf->e, &elf->ehdr)) {
(*err) = "failed to update executable header";
return -1;
}
if(elf->bits == 32) {
ehdr_buf = elf32_getehdr(elf->e);
ehdr_size = sizeof(Elf32_Ehdr);
} else {
ehdr_buf = elf64_getehdr(elf->e);
ehdr_size = sizeof(Elf64_Ehdr);
}
if(!ehdr_buf) {
(*err) = "failed to get executable header";
return -1;
}
off = lseek(elf->fd, 0, SEEK_SET);
if(off < 0) {
(*err) = "lseek failed";
return -1;
}
n = write(elf->fd, ehdr_buf, ehdr_size);
if(n != ehdr_size) {
(*err) = "write failed";
return -1;
}
return 0;
}
static int
build_file(Elf *src_elf, GElf_Ehdr *src_ehdr, Cmd_Info *cmd_info)
{
Elf_Scn *src_scn;
Elf_Scn *dst_scn;
int new_sh_name = 0; /* to hold the offset for the new */
/* section's name */
Elf *dst_elf = 0;
Elf_Data *elf_data;
Elf_Data *data;
int64_t scn_no, x;
size_t no_of_symbols = 0;
section_info_table *info;
unsigned int c = 0;
int fdtmp;
GElf_Shdr src_shdr;
GElf_Shdr dst_shdr;
GElf_Ehdr dst_ehdr;
GElf_Off new_offset = 0, r;
size_t shnum, shstrndx;
if (elf_getshnum(src_elf, &shnum) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
if (elf_getshstrndx(src_elf, &shstrndx) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
if ((fdtmp = open(elftmpfile, O_RDWR |
O_TRUNC | O_CREAT, (mode_t)0666)) == -1) {
error_message(OPEN_TEMP_ERROR,
SYSTEM_ERROR, strerror(errno),
prog, elftmpfile);
return (FAILURE);
}
if ((dst_elf = elf_begin(fdtmp, ELF_C_WRITE, (Elf *) 0)) == NULL) {
error_message(READ_ERROR,
LIBelf_ERROR, elf_errmsg(-1),
prog, elftmpfile);
(void) close(fdtmp);
return (FAILURE);
}
if (gelf_newehdr(dst_elf, gelf_getclass(src_elf)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
/* initialize dst_ehdr */
(void) gelf_getehdr(dst_elf, &dst_ehdr);
dst_ehdr = *src_ehdr;
/*
* flush the changes to the ehdr so the
* ident array is filled in.
*/
(void) gelf_update_ehdr(dst_elf, &dst_ehdr);
if (src_ehdr->e_phnum != 0) {
(void) elf_flagelf(dst_elf, ELF_C_SET, ELF_F_LAYOUT);
if (gelf_newphdr(dst_elf, src_ehdr->e_phnum) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
for (x = 0; x < src_ehdr->e_phnum; ++x) {
GElf_Phdr dst;
GElf_Phdr src;
/* LINTED */
(void) gelf_getphdr(src_elf, (int)x, &src);
/* LINTED */
(void) gelf_getphdr(dst_elf, (int)x, &dst);
(void) memcpy(&dst, &src, sizeof (GElf_Phdr));
/* LINTED */
(void) gelf_update_phdr(dst_elf, (int)x, &dst);
}
x = location(dst_ehdr.e_phoff, 0, src_elf);
if (x == AFTER)
new_offset = (GElf_Off)src_ehdr->e_ehsize;
}
scn_no = 1;
while ((src_scn = sec_table[scn_no].scn) != (Elf_Scn *) -1) {
info = &sec_table[scn_no];
/* If section should be copied to new file NOW */
if ((info->secno != (GElf_Word)DELETED) &&
info->secno <= scn_no) {
if ((dst_scn = elf_newscn(dst_elf)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
(void) gelf_getshdr(dst_scn, &dst_shdr);
(void) gelf_getshdr(info->scn, &src_shdr);
(void) memcpy(&dst_shdr, &src_shdr, sizeof (GElf_Shdr));
/*
* Update link and info fields
* The sh_link field may have special values so
* check them first.
*/
if ((src_shdr.sh_link >= shnum) ||
(src_shdr.sh_link == 0))
dst_shdr.sh_link = src_shdr.sh_link;
else if ((int)sec_table[src_shdr.sh_link].secno < 0)
dst_shdr.sh_link = 0;
else
dst_shdr.sh_link =
sec_table[src_shdr.sh_link].secno;
if ((src_shdr.sh_type == SHT_REL) ||
(src_shdr.sh_type == SHT_RELA)) {
if ((src_shdr.sh_info >= shnum) ||
((int)sec_table[src_shdr.
sh_info].secno < 0))
dst_shdr.sh_info = 0;
else
dst_shdr.sh_info =
sec_table[src_shdr.sh_info].secno;
}
data = sec_table[scn_no].data;
if ((elf_data = elf_newdata(dst_scn)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
*elf_data = *data;
/* SHT_{DYNSYM, SYMTAB} might need some change */
if (((src_shdr.sh_type == SHT_SYMTAB) ||
(src_shdr.sh_type == SHT_DYNSYM)) &&
src_shdr.sh_entsize != 0 &&
(cmd_info->no_of_delete != 0 ||
cmd_info->no_of_nulled != 0)) {
char *new_sym;
no_of_symbols = src_shdr.sh_size /
src_shdr.sh_entsize;
new_sym = malloc(no_of_symbols *
src_shdr.sh_entsize);
if (new_sym == NULL) {
error_message(MALLOC_ERROR,
PLAIN_ERROR, (char *)0, prog);
mcs_exit(FAILURE);
}
/* CSTYLED */
elf_data->d_buf = (void *) new_sym;
for (c = 0; c < no_of_symbols; c++) {
GElf_Sym csym;
(void) gelf_getsym(data, c, &csym);
if ((csym.st_shndx < SHN_LORESERVE) &&
(csym.st_shndx != SHN_UNDEF)) {
section_info_table *i;
i = &sec_table[csym.st_shndx];
if (((int)i->secno !=
DELETED) &&
((int)i->secno != NULLED))
csym.st_shndx =
i->secno;
else {
if (src_shdr.sh_type ==
SHT_SYMTAB)
/*
* The section which
* this * symbol relates
* to is removed.
* There is no way to
* specify this fact,
* just change the shndx
* to 1.
*/
csym.st_shndx = 1;
else {
/*
* If this is in a
* .dynsym, NULL it out.
*/
csym.st_shndx = 0;
csym.st_name = 0;
csym.st_value = 0;
csym.st_size = 0;
csym.st_info = 0;
csym.st_other = 0;
csym.st_shndx = 0;
}
}
}
(void) gelf_update_sym(elf_data, c,
&csym);
}
}
/* update SHT_SYMTAB_SHNDX */
if ((src_shdr.sh_type == SHT_SYMTAB_SHNDX) &&
(src_shdr.sh_entsize != 0) &&
((cmd_info->no_of_delete != 0) ||
(cmd_info->no_of_nulled != 0))) {
GElf_Word *oldshndx;
GElf_Word *newshndx;
uint_t entcnt;
entcnt = src_shdr.sh_size /
src_shdr.sh_entsize;
oldshndx = data->d_buf;
newshndx = malloc(entcnt *
src_shdr.sh_entsize);
if (newshndx == NULL) {
error_message(MALLOC_ERROR,
PLAIN_ERROR, (char *)0, prog);
mcs_exit(FAILURE);
}
elf_data->d_buf = (void *)newshndx;
for (c = 0; c < entcnt; c++) {
if (oldshndx[c] != SHN_UNDEF) {
section_info_table *i;
i = &sec_table[oldshndx[c]];
if (((int)i->secno !=
DELETED) &&
((int)i->secno != NULLED))
newshndx[c] = i->secno;
else
newshndx[c] =
oldshndx[c];
} else
newshndx[c] =
oldshndx[c];
}
}
/*
* If the section is to be updated,
* do so.
*/
if (ISCANDIDATE(info->flags)) {
if ((GET_LOC(info->flags) == PRIOR) &&
(((int)info->secno == NULLED) ||
((int)info->secno == EXPANDED) ||
((int)info->secno == SHRUNK))) {
/*
* The section is updated,
* but the position is not too
* good. Need to NULL this out.
*/
dst_shdr.sh_name = 0;
dst_shdr.sh_type = SHT_PROGBITS;
if ((int)info->secno != NULLED) {
(cmd_info->no_of_moved)++;
SET_MOVING(info->flags);
}
} else {
/*
* The section is positioned AFTER,
* or there are no segments.
* It is safe to update this section.
*/
data = sec_table[scn_no].mdata;
*elf_data = *data;
dst_shdr.sh_size = elf_data->d_size;
}
}
/* add new section name to shstrtab? */
else if (!Sect_exists &&
(new_sec_string != NULL) &&
(scn_no == shstrndx) &&
(dst_shdr.sh_type == SHT_STRTAB) &&
((src_ehdr->e_phnum == 0) ||
((x = scn_location(dst_scn, dst_elf)) != IN) ||
(x != PRIOR))) {
size_t sect_len;
sect_len = strlen(SECT_NAME);
if ((elf_data->d_buf =
malloc((dst_shdr.sh_size +
sect_len + 1))) == NULL) {
error_message(MALLOC_ERROR,
PLAIN_ERROR, (char *)0, prog);
mcs_exit(FAILURE);
}
/* put original data plus new data in section */
(void) memcpy(elf_data->d_buf,
data->d_buf, data->d_size);
(void) memcpy(&((char *)elf_data->d_buf)
[data->d_size],
SECT_NAME,
sect_len + 1);
/* LINTED */
new_sh_name = (int)dst_shdr.sh_size;
dst_shdr.sh_size += sect_len + 1;
elf_data->d_size += sect_len + 1;
}
/*
* Compute offsets.
*/
if (src_ehdr->e_phnum != 0) {
/*
* Compute section offset.
*/
if (off_table[scn_no] == 0) {
if (dst_shdr.sh_addralign != 0) {
r = new_offset %
dst_shdr.sh_addralign;
if (r)
new_offset +=
dst_shdr.sh_addralign - r;
}
dst_shdr.sh_offset = new_offset;
elf_data->d_off = 0;
} else {
if (nobits_table[scn_no] == 0)
new_offset = off_table[scn_no];
}
if (nobits_table[scn_no] == 0)
new_offset += dst_shdr.sh_size;
}
}
(void) gelf_update_shdr(dst_scn, &dst_shdr); /* flush changes */
scn_no++;
}
/*
* This is the real new section.
*/
if (!Sect_exists && new_sec_string != NULL) {
size_t string_size;
string_size = strlen(new_sec_string) + 1;
if ((dst_scn = elf_newscn(dst_elf)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
(void) gelf_getshdr(dst_scn, &dst_shdr);
dst_shdr.sh_name = new_sh_name;
dst_shdr.sh_type = SHT_PROGBITS;
dst_shdr.sh_flags = 0;
dst_shdr.sh_addr = 0;
if (src_ehdr->e_phnum != NULL)
dst_shdr.sh_offset = new_offset;
else
dst_shdr.sh_offset = 0;
dst_shdr.sh_size = string_size + 1;
dst_shdr.sh_link = 0;
dst_shdr.sh_info = 0;
dst_shdr.sh_addralign = 1;
dst_shdr.sh_entsize = 0;
(void) gelf_update_shdr(dst_scn, &dst_shdr); /* flush changes */
if ((elf_data = elf_newdata(dst_scn)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
elf_data->d_size = string_size + 1;
if ((elf_data->d_buf = (char *)
calloc(1, string_size + 1)) == NULL) {
error_message(MALLOC_ERROR,
PLAIN_ERROR, (char *)0,
prog);
mcs_exit(FAILURE);
}
(void) memcpy(&((char *)elf_data->d_buf)[1],
new_sec_string, string_size);
elf_data->d_align = 1;
new_offset += string_size + 1;
}
/*
* If there are sections which needed to be moved,
* then do it here.
*/
if (cmd_info->no_of_moved != 0) {
int cnt;
info = &sec_table[0];
for (cnt = 0; cnt < shnum; cnt++, info++) {
if ((GET_MOVING(info->flags)) == 0)
continue;
if ((src_scn = elf_getscn(src_elf, info->osecno)) ==
NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
if (gelf_getshdr(src_scn, &src_shdr) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
if ((dst_scn = elf_newscn(dst_elf)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
if (gelf_getshdr(dst_scn, &dst_shdr) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
dst_shdr = src_shdr;
data = info->mdata;
dst_shdr.sh_offset = new_offset; /* UPDATE fields */
dst_shdr.sh_size = data->d_size;
if ((shnum >= src_shdr.sh_link) ||
(src_shdr.sh_link == 0))
dst_shdr.sh_link = src_shdr.sh_link;
else
dst_shdr.sh_link =
sec_table[src_shdr.sh_link].osecno;
if ((shnum >= src_shdr.sh_info) ||
(src_shdr.sh_info == 0))
dst_shdr.sh_info = src_shdr.sh_info;
else
dst_shdr.sh_info =
sec_table[src_shdr.sh_info].osecno;
(void) gelf_update_shdr(dst_scn, &dst_shdr);
if ((elf_data = elf_newdata(dst_scn)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
(void) memcpy(elf_data, data, sizeof (Elf_Data));
new_offset += data->d_size;
}
}
/*
* In the event that the position of the sting table has changed,
* as a result of deleted sections, update the ehdr->e_shstrndx.
*/
if ((shstrndx > 0) && (shnum > 0) &&
(sec_table[shstrndx].secno < shnum)) {
if (sec_table[shstrndx].secno < SHN_LORESERVE) {
dst_ehdr.e_shstrndx =
sec_table[dst_ehdr.e_shstrndx].secno;
} else {
Elf_Scn *_scn;
GElf_Shdr shdr0;
/*
* If shstrndx requires 'Extended ELF Sections'
* then it is stored in shdr[0].sh_link
*/
dst_ehdr.e_shstrndx = SHN_XINDEX;
if ((_scn = elf_getscn(dst_elf, 0)) == NULL) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
(void) gelf_getshdr(_scn, &shdr0);
shdr0.sh_link = sec_table[shstrndx].secno;
(void) gelf_update_shdr(_scn, &shdr0);
}
}
if (src_ehdr->e_phnum != 0) {
size_t align = gelf_fsize(dst_elf, ELF_T_ADDR, 1, EV_CURRENT);
/* UPDATE location of program header table */
if (location(dst_ehdr.e_phoff, 0, dst_elf) == AFTER) {
r = new_offset % align;
if (r)
new_offset += align - r;
dst_ehdr.e_phoff = new_offset;
new_offset += dst_ehdr.e_phnum
* dst_ehdr.e_phentsize;
}
/* UPDATE location of section header table */
if ((location(dst_ehdr.e_shoff, 0, src_elf) == AFTER) ||
((location(dst_ehdr.e_shoff, 0, src_elf) == PRIOR) &&
(!Sect_exists && new_sec_string != NULL))) {
r = new_offset % align;
if (r)
new_offset += align - r;
dst_ehdr.e_shoff = new_offset;
}
free(b_e_seg_table);
/*
* The NOTE segment is the one segment whos
* sections might get moved by mcs processing.
* Make sure that the NOTE segments offset points
* to the .note section.
*/
if ((notesegndx != -1) && (notesctndx != -1) &&
(sec_table[notesctndx].secno)) {
Elf_Scn * notescn;
GElf_Shdr nshdr;
notescn = elf_getscn(dst_elf,
sec_table[notesctndx].secno);
(void) gelf_getshdr(notescn, &nshdr);
if (gelf_getclass(dst_elf) == ELFCLASS32) {
Elf32_Phdr * ph = elf32_getphdr(dst_elf) +
notesegndx;
/* LINTED */
ph->p_offset = (Elf32_Off)nshdr.sh_offset;
} else {
Elf64_Phdr * ph = elf64_getphdr(dst_elf) +
notesegndx;
ph->p_offset = (Elf64_Off)nshdr.sh_offset;
}
}
}
/* copy ehdr changes back into real ehdr */
(void) gelf_update_ehdr(dst_elf, &dst_ehdr);
if (elf_update(dst_elf, ELF_C_WRITE) < 0) {
error_message(LIBELF_ERROR,
LIBelf_ERROR, elf_errmsg(-1), prog);
return (FAILURE);
}
(void) elf_end(dst_elf);
(void) close(fdtmp);
return (SUCCESS);
}
static int
ctf_write_elf(ctf_file_t *fp, Elf *src, Elf *dst, int flags)
{
GElf_Ehdr sehdr, dehdr;
Elf_Scn *sscn, *dscn;
Elf_Data *sdata, *ddata;
GElf_Shdr shdr;
int symtab_idx = -1;
off_t new_offset = 0;
off_t ctfnameoff = 0;
int compress = (flags & CTF_ELFWRITE_F_COMPRESS);
int *secxlate = NULL;
int srcidx, dstidx, pad, i;
int curnmoff = 0;
int changing = 0;
int ret;
size_t nshdr, nphdr, strndx;
void *strdatabuf = NULL, *symdatabuf = NULL;
size_t strdatasz = 0, symdatasz = 0;
void *cdata = NULL;
size_t elfsize, asize;
if ((flags & ~(CTF_ELFWRITE_F_COMPRESS)) != 0) {
ret = ctf_set_errno(fp, EINVAL);
goto out;
}
if (gelf_newehdr(dst, gelf_getclass(src)) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (gelf_getehdr(src, &sehdr) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
(void) memcpy(&dehdr, &sehdr, sizeof (GElf_Ehdr));
if (gelf_update_ehdr(dst, &dehdr) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
/*
* Use libelf to get the number of sections and the string section to
* deal with ELF files that may have a large number of sections. We just
* always use this to make our live easier.
*/
if (elf_getphdrnum(src, &nphdr) != 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (elf_getshdrnum(src, &nshdr) != 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (elf_getshdrstrndx(src, &strndx) != 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
/*
* Neither the existing debug sections nor the SUNW_ctf sections (new or
* existing) are SHF_ALLOC'd, so they won't be in areas referenced by
* program headers. As such, we can just blindly copy the program
* headers from the existing file to the new file.
*/
if (nphdr != 0) {
(void) elf_flagelf(dst, ELF_C_SET, ELF_F_LAYOUT);
if (gelf_newphdr(dst, nphdr) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
for (i = 0; i < nphdr; i++) {
GElf_Phdr phdr;
if (gelf_getphdr(src, i, &phdr) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (gelf_update_phdr(dst, i, &phdr) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
}
}
secxlate = ctf_alloc(sizeof (int) * nshdr);
for (srcidx = dstidx = 0; srcidx < nshdr; srcidx++) {
Elf_Scn *scn = elf_getscn(src, srcidx);
GElf_Shdr shdr;
char *sname;
if (gelf_getshdr(scn, &shdr) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
sname = elf_strptr(src, strndx, shdr.sh_name);
if (sname == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (strcmp(sname, CTF_ELF_SCN_NAME) == 0) {
secxlate[srcidx] = -1;
} else {
secxlate[srcidx] = dstidx++;
curnmoff += strlen(sname) + 1;
}
new_offset = (off_t)dehdr.e_phoff;
}
for (srcidx = 1; srcidx < nshdr; srcidx++) {
char *sname;
sscn = elf_getscn(src, srcidx);
if (gelf_getshdr(sscn, &shdr) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (secxlate[srcidx] == -1) {
changing = 1;
continue;
}
dscn = elf_newscn(dst);
if (dscn == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
/*
* If this file has program headers, we need to explicitly lay
* out sections. If none of the sections prior to this one have
* been removed, then we can just use the existing location. If
* one or more sections have been changed, then we need to
* adjust this one to avoid holes.
*/
if (changing && nphdr != 0) {
pad = new_offset % shdr.sh_addralign;
if (pad != 0)
new_offset += shdr.sh_addralign - pad;
shdr.sh_offset = new_offset;
}
shdr.sh_link = secxlate[shdr.sh_link];
if (shdr.sh_type == SHT_REL || shdr.sh_type == SHT_RELA)
shdr.sh_info = secxlate[shdr.sh_info];
sname = elf_strptr(src, strndx, shdr.sh_name);
if (sname == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if ((sdata = elf_getdata(sscn, NULL)) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if ((ddata = elf_newdata(dscn)) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
bcopy(sdata, ddata, sizeof (Elf_Data));
if (srcidx == strndx) {
char seclen = strlen(CTF_ELF_SCN_NAME);
strdatasz = ddata->d_size + shdr.sh_size +
seclen + 1;
ddata->d_buf = strdatabuf = ctf_alloc(strdatasz);
if (ddata->d_buf == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size);
(void) strcpy((caddr_t)ddata->d_buf + shdr.sh_size,
CTF_ELF_SCN_NAME);
ctfnameoff = (off_t)shdr.sh_size;
shdr.sh_size += seclen + 1;
ddata->d_size += seclen + 1;
if (nphdr != 0)
changing = 1;
}
if (shdr.sh_type == SHT_SYMTAB && shdr.sh_entsize != 0) {
int nsym = shdr.sh_size / shdr.sh_entsize;
symtab_idx = secxlate[srcidx];
symdatasz = shdr.sh_size;
ddata->d_buf = symdatabuf = ctf_alloc(symdatasz);
if (ddata->d_buf == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
(void) bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size);
for (i = 0; i < nsym; i++) {
GElf_Sym sym;
short newscn;
(void) gelf_getsym(ddata, i, &sym);
if (sym.st_shndx >= SHN_LORESERVE)
continue;
if ((newscn = secxlate[sym.st_shndx]) !=
sym.st_shndx) {
sym.st_shndx =
(newscn == -1 ? 1 : newscn);
if (gelf_update_sym(ddata, i, &sym) ==
0) {
ret = ctf_set_errno(fp,
ECTF_ELF);
goto out;
}
}
}
}
if (gelf_update_shdr(dscn, &shdr) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
new_offset = (off_t)shdr.sh_offset;
if (shdr.sh_type != SHT_NOBITS)
new_offset += shdr.sh_size;
}
if (symtab_idx == -1) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
/* Add the ctf section */
if ((dscn = elf_newscn(dst)) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (gelf_getshdr(dscn, &shdr) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
shdr.sh_name = ctfnameoff;
shdr.sh_type = SHT_PROGBITS;
shdr.sh_size = fp->ctf_size;
shdr.sh_link = symtab_idx;
shdr.sh_addralign = 4;
if (changing && nphdr != 0) {
pad = new_offset % shdr.sh_addralign;
if (pad)
new_offset += shdr.sh_addralign - pad;
shdr.sh_offset = new_offset;
new_offset += shdr.sh_size;
}
if ((ddata = elf_newdata(dscn)) == NULL) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (compress != 0) {
int err;
if (ctf_zopen(&err) == NULL) {
ret = ctf_set_errno(fp, err);
goto out;
}
if ((err = ctf_compress(fp, &cdata, &asize, &elfsize)) != 0) {
ret = ctf_set_errno(fp, err);
goto out;
}
ddata->d_buf = cdata;
ddata->d_size = elfsize;
} else {
ddata->d_buf = (void *)fp->ctf_base;
ddata->d_size = fp->ctf_size;
}
ddata->d_align = shdr.sh_addralign;
if (gelf_update_shdr(dscn, &shdr) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
/* update the section header location */
if (nphdr != 0) {
size_t align = gelf_fsize(dst, ELF_T_ADDR, 1, EV_CURRENT);
size_t r = new_offset % align;
if (r)
new_offset += align - r;
dehdr.e_shoff = new_offset;
}
/* commit to disk */
if (sehdr.e_shstrndx == SHN_XINDEX)
dehdr.e_shstrndx = SHN_XINDEX;
else
dehdr.e_shstrndx = secxlate[sehdr.e_shstrndx];
if (gelf_update_ehdr(dst, &dehdr) == 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
if (elf_update(dst, ELF_C_WRITE) < 0) {
ret = ctf_set_errno(fp, ECTF_ELF);
goto out;
}
ret = 0;
out:
if (strdatabuf != NULL)
ctf_free(strdatabuf, strdatasz);
if (symdatabuf != NULL)
ctf_free(symdatabuf, symdatasz);
if (cdata != NULL)
ctf_data_free(cdata, fp->ctf_size);
if (secxlate != NULL)
ctf_free(secxlate, sizeof (int) * nshdr);
return (ret);
}
int
main (int argc, char *argv[])
{
if (argc < 3)
error (EXIT_FAILURE, 0, "usage: %s FROMNAME TONAME", argv[0]);
elf_version (EV_CURRENT);
int infd = open (argv[1], O_RDONLY);
if (infd == -1)
error (EXIT_FAILURE, errno, "cannot open input file '%s'", argv[1]);
Elf *inelf = elf_begin (infd, ELF_C_READ, NULL);
if (inelf == NULL)
error (EXIT_FAILURE, 0, "problems opening '%s' as ELF file: %s",
argv[1], elf_errmsg (-1));
int outfd = creat (argv[2], 0666);
if (outfd == -1)
error (EXIT_FAILURE, errno, "cannot open output file '%s'", argv[2]);
Elf *outelf = elf_begin (outfd, ELF_C_WRITE, NULL);
if (outelf == NULL)
error (EXIT_FAILURE, 0, "problems opening '%s' as ELF file: %s",
argv[2], elf_errmsg (-1));
gelf_newehdr (outelf, gelf_getclass (inelf));
GElf_Ehdr ehdr_mem;
GElf_Ehdr *ehdr;
gelf_update_ehdr (outelf, (ehdr = gelf_getehdr (inelf, &ehdr_mem)));
if (ehdr->e_phnum > 0)
{
int cnt;
if (gelf_newphdr (outelf, ehdr->e_phnum) == 0)
error (EXIT_FAILURE, 0, "cannot create program header: %s",
elf_errmsg (-1));
for (cnt = 0; cnt < ehdr->e_phnum; ++cnt)
{
GElf_Phdr phdr_mem;
gelf_update_phdr (outelf, cnt, gelf_getphdr (inelf, cnt, &phdr_mem));
}
}
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (inelf, scn)) != NULL)
{
Elf_Scn *newscn = elf_newscn (outelf);
GElf_Shdr shdr_mem;
gelf_update_shdr (newscn, gelf_getshdr (scn, &shdr_mem));
*elf_newdata (newscn) = *elf_getdata (scn, NULL);
}
elf_flagelf (outelf, ELF_C_SET, ELF_F_LAYOUT);
if (elf_update (outelf, ELF_C_WRITE) == -1)
error (EXIT_FAILURE, 0, "elf_update failed: %s", elf_errmsg (-1));
close (outfd);
return 0;
}
int main(int argc, const char *argv[]) {
ssize_t bytes_written; // only used to silence compiler warnings
if (argc < 2)
errx(EX_USAGE, "Usage: PatchEntry <binary>");
if (elf_version(EV_CURRENT) == EV_NONE)
errx(EX_SOFTWARE, "Invalid ELF version: %s", elf_errmsg(-1));
int fd = open(argv[1], O_RDWR);
if (fd == -1)
err(EX_NOINPUT, "open() failed");
Elf *e;
e = elf_begin(fd, ELF_C_RDWR, NULL);
if (e == nullptr)
errx(EX_SOFTWARE, "Failed to read from ELF file: %s", elf_errmsg(-1));
if (elf_kind(e) != ELF_K_ELF)
errx(EX_SOFTWARE, "File is not an ELF object");
// Read the ELF header to find the entry point
// FIXME: check the class/architecture, make sure it's the same as ours
GElf_Ehdr elf_hdr;
if (gelf_getehdr(e, &elf_hdr) == NULL)
errx(EX_SOFTWARE, "Failed to read ELF header: %s", elf_errmsg(-1));
auto dt_init = FindDynamicInit(e);
auto dt_init_ofs = 0;
if (dt_init) {
dt_init_ofs = dt_init->info.second.sh_offset +
dt_init->data->d_off +
dt_init->index * sizeof(Elf_Dyn) +
offsetof(Elf_Dyn, d_un);
}
auto pit_sym = FindSymbol(e, kProgramInfoTableName);
auto pit_info = FindSectionDataByAddr(e, pit_sym.st_value);
auto pit_ofs = std::get<0>(pit_info).second.sh_offset + // Section file offset
std::get<1>(pit_info)->d_off + // Elf_Data offset
std::get<2>(pit_info); // Offset relative to Elf_Data
#if 1
if (dt_init)
printf("Old ELF entry:%p DT_INIT:%p@%x PIT:%p@%lx\n",
(void*) elf_hdr.e_entry,
(void*) dt_init->dyn_section.d_un.d_ptr,
dt_init_ofs,
(void*) pit_sym.st_value,
pit_ofs);
else
printf("Old ELF entry:%p DT_INIT:NULL PIT:%p@%lx\n",
(void*) elf_hdr.e_entry,
(void*) pit_sym.st_value,
pit_ofs);
#endif
// Replace the ProgramInfoTable values
auto pit_data = std::get<1>(pit_info);
auto orig_pit = reinterpret_cast<TrapProgramInfoTable*>(
reinterpret_cast<uint8_t*>(pit_data->d_buf) + std::get<2>(pit_info));
TrapProgramInfoTable pit = *orig_pit; // Need to copy it here, since elf_end releases it
if (pit.num_sections != 0)
errx(EX_USAGE, "Binary already contains full ProgramInfoTable structure");
if (dt_init)
pit.orig_dt_init = dt_init->dyn_section.d_un.d_ptr;
else
pit.orig_dt_init = 0;
pit.orig_entry = elf_hdr.e_entry;
// Find executable sections in the binary (.text/.plt/others)
// then copy them over to the PIT
pit.num_sections = TRAP_NUM_SECTIONS;
for (size_t i = 0; i < TRAP_NUM_SECTIONS; i++) {
auto sec_info = FindSectionByName(e, kExecSections[i][0]);
if (sec_info.first != nullptr) {
pit.sections[i].start = sec_info.second.sh_addr;
pit.sections[i].size = sec_info.second.sh_size;
}
auto trap_sec_info = FindSectionByName(e, kExecSections[i][1]);
if (trap_sec_info.first != nullptr) {
pit.sections[i].trap = trap_sec_info.second.sh_addr;
pit.sections[i].trap_size = trap_sec_info.second.sh_size;
}
}
// Set the new entry point addresses
auto entry_trampoline_sym = FindSymbol(e, kEntryTrampolineName);
auto init_trampoline_sym = FindSymbol(e, kInitTrampolineName);
elf_hdr.e_entry = entry_trampoline_sym.st_value;
auto new_dt_init = static_cast<ArchPointer>(init_trampoline_sym.st_value);
// Find export trampolines
auto xptramp_info = FindSectionByName(e, ".xptramp");
DynamicSymbolMap dyn_sym_map;
ExportTrampolineVector xptramp_vec;
size_t xptramp_shndx = 0;
if (xptramp_info.first != nullptr) {
pit.xptramp_start = xptramp_info.second.sh_addr;
pit.xptramp_size = xptramp_info.second.sh_size;
dyn_sym_map = FindDynamicSymbols(e);
xptramp_vec = FindExportTrampolines(e, xptramp_info);
xptramp_shndx = elf_ndxscn(xptramp_info.first);
}
// Update the ELF header, then write it out
// There's some pretty ugly behavior from libelf here:
// if we let it handle the layout, it mis-aligns the data sections
// It also doesn't seem to update the contents correctly,
// so we do that manually
elf_flagelf(e, ELF_C_SET, ELF_F_LAYOUT);
gelf_update_ehdr(e, &elf_hdr);
if (elf_update(e, ELF_C_WRITE) <= 0)
errx(EX_SOFTWARE, "Couldn't update ELF file: %s", elf_errmsg(-1));
elf_end(e);
// FIXME: libelf shenanigans force us to
// write data out to the file manually
// 1) DT_INIT inside .dynamic
if (dt_init) {
printf("writing new DT_INIT: 0x%lu\n", new_dt_init);
lseek(fd, dt_init_ofs, SEEK_SET);
bytes_written = write(fd, &new_dt_init, sizeof(new_dt_init));
}
// 2) The ProgramInfoTable
lseek(fd, pit_ofs, SEEK_SET);
bytes_written = write(fd, &pit, sizeof(pit));
// 3) Exported symbols
WriteExportSymbols(fd, xptramp_info, xptramp_vec, xptramp_shndx, dyn_sym_map);
close(fd);
return 0;
}
int
main(int argc, char **argv)
{
GElf_Ehdr ehdr;
Elf *elf;
Elf_Kind kind;
int type = ELFOSABI_NONE;
int retval = 0;
int ch, change = 0, verbose = 0, force = 0, listed = 0;
if (elf_version(EV_CURRENT) == EV_NONE)
errx(EXIT_FAILURE, "elf_version error");
while ((ch = getopt_long(argc, argv, "Vf:hlt:v", brandelf_longopts,
NULL)) != -1)
switch (ch) {
case 'f':
if (change)
errx(EXIT_FAILURE, "ERROR: the -f option is "
"incompatible with the -t option.");
force = 1;
type = atoi(optarg);
if (errno == ERANGE || type < 0 || type > 255) {
warnx("ERROR: invalid argument to option "
"-f: %s", optarg);
usage();
}
break;
case 'h':
usage();
break;
case 'l':
printelftypes();
listed = 1;
break;
case 'v':
verbose = 1;
break;
case 't':
if (force)
errx(EXIT_FAILURE, "the -t option is "
"incompatible with the -f option.");
if ((type = elftype(optarg)) == -1) {
warnx("ERROR: invalid ELF type '%s'", optarg);
usage();
}
change = 1;
break;
case 'V':
printversion();
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (!argc) {
if (listed)
exit(0);
else {
warnx("no file(s) specified");
usage();
}
}
while (argc) {
int fd;
elf = NULL;
if ((fd = open(argv[0], (change || force) ? O_RDWR :
O_RDONLY, 0)) < 0) {
warn("error opening file %s", argv[0]);
retval = 1;
goto fail;
}
if ((elf = elf_begin(fd, (change || force) ? ELF_C_RDWR :
ELF_C_READ, NULL)) == NULL) {
warnx("elf_begin failed: %s", elf_errmsg(-1));
retval = 1;
goto fail;
}
if ((kind = elf_kind(elf)) != ELF_K_ELF) {
if (kind == ELF_K_AR)
warnx("file '%s' is an archive.", argv[0]);
else
warnx("file '%s' is not an ELF file.",
argv[0]);
retval = 1;
goto fail;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
warnx("gelf_getehdr: %s", elf_errmsg(-1));
retval = 1;
goto fail;
}
if (!change && !force) {
fprintf(stdout,
"File '%s' is of brand '%s' (%u).\n",
argv[0], iselftype(ehdr.e_ident[EI_OSABI]),
ehdr.e_ident[EI_OSABI]);
if (!iselftype(type)) {
warnx("ELF ABI Brand '%u' is unknown",
type);
printelftypes();
}
} else {
/*
* Keep the existing layout of the ELF object.
*/
if (elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT) == 0) {
warnx("elf_flagelf failed: %s",
elf_errmsg(-1));
retval = 1;
goto fail;
}
/*
* Update the ABI type.
*/
ehdr.e_ident[EI_OSABI] = type;
if (gelf_update_ehdr(elf, &ehdr) == 0) {
warnx("gelf_update_ehdr error: %s",
elf_errmsg(-1));
retval = 1;
goto fail;
}
/*
* Write back changes.
*/
if (elf_update(elf, ELF_C_WRITE) == -1) {
warnx("elf_update error: %s", elf_errmsg(-1));
retval = 1;
goto fail;
}
}
fail:
if (elf)
elf_end(elf);
if (fd >= 0 && close(fd) == -1) {
warnx("%s: close error", argv[0]);
retval = 1;
}
argc--;
argv++;
}
return (retval);
}
