int
write_phdr(elf_data_t *elf, inject_data_t *inject, char **err)
{
off_t off;
size_t n, phdr_size;
Elf32_Phdr *phdr_list32;
Elf64_Phdr *phdr_list64;
void *phdr_buf;
if(!gelf_update_phdr(elf->e, inject->pidx, &inject->phdr)) {
(*err) = "failed to update program header";
return -1;
}
if(elf->bits == 32) {
phdr_list32 = elf32_getphdr(elf->e);
if(!phdr_list32) {
phdr_buf = NULL;
} else {
phdr_buf = &phdr_list32[inject->pidx];
phdr_size = sizeof(Elf32_Phdr);
}
} else {
phdr_list64 = elf64_getphdr(elf->e);
if(!phdr_list64) {
phdr_buf = NULL;
} else {
phdr_buf = &phdr_list64[inject->pidx];
phdr_size = sizeof(Elf64_Phdr);
}
}
if(!phdr_buf) {
(*err) = "failed to get program header";
return -1;
}
off = lseek(elf->fd, elf->ehdr.e_phoff + inject->pidx*elf->ehdr.e_phentsize, SEEK_SET);
if(off < 0) {
(*err) = "lseek failed";
return -1;
}
n = write(elf->fd, phdr_buf, phdr_size);
if(n != phdr_size) {
(*err) = "write failed";
return -1;
}
return 0;
}
/* load_kernel loads an ELF file as a kernel. */
uintptr_t
load_kernel(char *filename)
{
Elf64_Ehdr *ehdr;
Elf *elf;
size_t phnum = 0;
Elf64_Phdr *hdrs;
int fd;
elf_version(EV_CURRENT);
fd = open(filename, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "Can't open %s: %r\n", filename);
return 0;
}
elf = elf_begin(fd, ELF_C_READ, NULL);
if (elf == NULL) {
fprintf(stderr, "%s: cannot read %s ELF file.\n", __func__, filename);
close(fd);
return 0;
}
ehdr = elf64_getehdr(elf);
if (ehdr == NULL) {
fprintf(stderr, "%s: cannot get exec header of %s.\n",
__func__, filename);
goto fail;
}
fprintf(stderr, "%s ELF entry point is %p\n", filename,
(void *)ehdr->e_entry);
if (elf_getphdrnum(elf, &phnum) < 0) {
fprintf(stderr, "%s: cannot get program header num of %s.\n",
__func__, filename);
goto fail;
}
fprintf(stderr, "%s has %p program headers\n", filename, phnum);
hdrs = elf64_getphdr(elf);
if (hdrs == NULL) {
fprintf(stderr, "%s: cannot get program headers of %s.\n",
__func__, filename);
goto fail;
}
for (int i = 0; i < phnum; i++) {
size_t tot;
Elf64_Phdr *h = &hdrs[i];
uintptr_t pa;
fprintf(stderr,
"%d: type 0x%lx flags 0x%lx offset 0x%lx vaddr 0x%lx paddr 0x%lx size 0x%lx memsz 0x%lx align 0x%lx\n",
i,
h->p_type, /* Segment type */
h->p_flags, /* Segment flags */
h->p_offset, /* Segment file offset */
h->p_vaddr, /* Segment virtual address */
h->p_paddr, /* Segment physical address */
h->p_filesz, /* Segment size in file */
h->p_memsz, /* Segment size in memory */
h->p_align /* Segment alignment */);
if (h->p_type != PT_LOAD)
continue;
if ((h->p_flags & (PF_R | PF_W | PF_X)) == 0)
continue;
pa = h->p_paddr;
fprintf(stderr,
"Read header %d @offset %p to %p (elf PA is %p) %d bytes:",
i, h->p_offset, pa, h->p_paddr, h->p_filesz);
tot = 0;
while (tot < h->p_filesz) {
int amt = pread(fd, (void *)(pa + tot), h->p_filesz - tot,
h->p_offset + tot);
if (amt < 1)
break;
tot += amt;
}
fprintf(stderr, "read a total of %d bytes\n", tot);
if (tot < h->p_filesz) {
fprintf(stderr, "%s: got %d bytes, wanted %d bytes\n",
filename, tot, h->p_filesz);
goto fail;
}
}
close(fd);
elf_end(elf);
return ehdr->e_entry;
fail:
close(fd);
elf_end(elf);
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);
}
