int
ELFNAMEEND(check)(int fd, const char *fn)
{
Elf_Ehdr eh;
struct stat sb;
unsigned char data;
/*
* Check the header to maek sure it's an ELF file (of the
* appropriate size).
*/
if (fstat(fd, &sb) == -1)
return 0;
if (sb.st_size < (off_t)(sizeof eh))
return 0;
if (read(fd, &eh, sizeof eh) != sizeof eh)
return 0;
if (IS_ELF(eh) == 0 || eh.e_ident[EI_CLASS] != ELFCLASS)
return 0;
data = eh.e_ident[EI_DATA];
switch (xe16toh(eh.e_machine)) {
case EM_386: break;
case EM_ALPHA: break;
#ifndef EM_AARCH64
#define EM_AARCH64 183
#endif
case EM_AARCH64: break;
case EM_ARM: break;
case EM_MIPS: break;
case /* EM_MIPS_RS3_LE */ EM_MIPS_RS4_BE: break;
case EM_PPC: break;
case EM_PPC64: break;
#ifndef EM_RISCV
#define EM_RISCV 243
#endif
case EM_RISCV: break;
case EM_SPARCV9: break;
case EM_X86_64: break;
/* ELFDEFNNAME(MACHDEP_ID_CASES) */
default:
return 0;
}
return 1;
}
/*
* This function 'hides' (some of) ELF executable file's symbols.
* It hides them by renaming them to "_$$hide$$ <filename> <symbolname>".
* Symbols in the global keep list, or which are marked as being undefined,
* are left alone.
*
* An old version of this code shuffled various tables around, turning
* global symbols to be hidden into local symbols. That lost on the
* mips, because CALL16 relocs must reference global symbols, and, if
* those symbols were being hidden, they were no longer global.
*
* The new renaming behaviour doesn't take global symbols out of the
* namespace. However, it's ... unlikely that there will ever be
* any collisions in practice because of the new method.
*/
int
ELFNAMEEND(hide)(int fd, const char *fn)
{
Elf_Ehdr ehdr;
struct shlayout *layoutp = NULL;
Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr, *shstrtabshdr;
Elf_Shdr shdrshdr;
Elf_Sym *symtabp = NULL;
char *shstrtabp = NULL, *strtabp = NULL;
Elf_Size nsyms, ewi;
Elf_Off off;
ssize_t shdrsize;
int rv, i, weird, l, m, r, strtabidx;
size_t nstrtab_size, nstrtab_nextoff, fn_size, size;
char *nstrtabp = NULL;
unsigned char data;
const char *weirdreason = NULL;
void *buf;
Elf_Half shnum;
rv = 0;
if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr)
goto bad;
data = ehdr.e_ident[EI_DATA];
shnum = xe16toh(ehdr.e_shnum);
shdrsize = shnum * xe16toh(ehdr.e_shentsize);
if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL)
goto bad;
if (xreadatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) !=
shdrsize)
goto bad;
symtabshdr = strtabshdr = shstrtabshdr = NULL;
weird = 0;
for (i = 0; i < shnum; i++) {
switch (xe32toh(shdrp[i].sh_type)) {
case SHT_SYMTAB:
if (symtabshdr != NULL) {
weird = 1;
weirdreason = "multiple symbol tables";
}
symtabshdr = &shdrp[i];
strtabshdr = &shdrp[xe32toh(shdrp[i].sh_link)];
break;
case SHT_STRTAB:
if (i == xe16toh(ehdr.e_shstrndx))
shstrtabshdr = &shdrp[i];
break;
}
}
if (symtabshdr == NULL)
goto out;
if (strtabshdr == NULL) {
weird = 1;
weirdreason = "string table does not exist";
}
if (shstrtabshdr == NULL) {
weird = 1;
weirdreason = "section header string table does not exist";
}
if (weirdreason == NULL)
weirdreason = "unsupported";
if (weird) {
fprintf(stderr, "%s: weird executable (%s)\n", fn, weirdreason);
goto bad;
}
/*
* sort section layout table by offset
*/
layoutp = xmalloc((shnum + 1) * sizeof(struct shlayout),
fn, "layout table");
if (layoutp == NULL)
goto bad;
/* add a pseudo entry to represent the section header table */
shdrshdr.sh_offset = ehdr.e_shoff;
shdrshdr.sh_size = htoxew(shdrsize);
shdrshdr.sh_addralign = htoxew(ELFSIZE / 8);
layoutp[shnum].shdr = &shdrshdr;
/* insert and sort normal section headers */
for (i = shnum; i-- != 0;) {
l = i + 1;
r = shnum;
while (l <= r) {
m = ( l + r) / 2;
if (xewtoh(shdrp[i].sh_offset) >
xewtoh(layoutp[m].shdr->sh_offset))
l = m + 1;
else
r = m - 1;
}
if (r != i) {
memmove(&layoutp[i], &layoutp[i + 1],
sizeof(struct shlayout) * (r - i));
}
layoutp[r].shdr = &shdrp[i];
layoutp[r].bufp = NULL;
}
++shnum;
/*
* load up everything we need
*/
/* load section string table for debug use */
if ((size = xewtoh(shstrtabshdr->sh_size)) == 0)
goto bad;
if ((shstrtabp = xmalloc(size, fn, "section string table")) == NULL)
goto bad;
if ((size_t)xreadatoff(fd, shstrtabp, xewtoh(shstrtabshdr->sh_offset),
size, fn) != size)
goto bad;
if (shstrtabp[size - 1] != '\0')
goto bad;
/* we need symtab, strtab, and everything behind strtab */
strtabidx = INT_MAX;
for (i = 0; i < shnum; i++) {
if (layoutp[i].shdr == &shdrshdr) {
/* not load section header again */
layoutp[i].bufp = shdrp;
continue;
}
if (layoutp[i].shdr == shstrtabshdr) {
/* not load section string table again */
layoutp[i].bufp = shstrtabp;
continue;
}
if (layoutp[i].shdr == strtabshdr)
strtabidx = i;
if (layoutp[i].shdr == symtabshdr || i >= strtabidx) {
off = xewtoh(layoutp[i].shdr->sh_offset);
if ((size = xewtoh(layoutp[i].shdr->sh_size)) == 0)
goto bad;
layoutp[i].bufp = xmalloc(size, fn,
shstrtabp + xewtoh(layoutp[i].shdr->sh_name));
if (layoutp[i].bufp == NULL)
goto bad;
if ((size_t)xreadatoff(fd, layoutp[i].bufp, off, size, fn) !=
size)
goto bad;
/* set symbol table and string table */
if (layoutp[i].shdr == symtabshdr) {
symtabp = layoutp[i].bufp;
} else if (layoutp[i].shdr == strtabshdr) {
strtabp = layoutp[i].bufp;
if (strtabp[size - 1] != '\0')
goto bad;
}
}
}
nstrtab_size = 256;
nstrtabp = xmalloc(nstrtab_size, fn, "new string table");
if (nstrtabp == NULL)
goto bad;
nstrtab_nextoff = 0;
fn_size = strlen(fn);
/* Prepare data structures for symbol movement. */
nsyms = xewtoh(symtabshdr->sh_size) / xewtoh(symtabshdr->sh_entsize);
/* move symbols, making them local */
for (ewi = 0; ewi < nsyms; ewi++) {
Elf_Sym *sp = &symtabp[ewi];
const char *symname = strtabp + xe32toh(sp->st_name);
size_t newent_len;
/*
* make sure there's size for the next entry, even if it's
* as large as it can be.
*
* "_$$hide$$ <filename> <symname><NUL>" ->
* 9 + 3 + sizes of fn and sym name
*/
while ((nstrtab_size - nstrtab_nextoff) <
strlen(symname) + fn_size + 12) {
nstrtab_size *= 2;
nstrtabp = xrealloc(nstrtabp, nstrtab_size, fn,
"new string table");
if (nstrtabp == NULL)
goto bad;
}
sp->st_name = htowew(nstrtab_nextoff);
/* if it's a keeper or is undefined, don't rename it. */
if (in_keep_list(symname) ||
(xe16toh(sp->st_shndx) == SHN_UNDEF)) {
newent_len = sprintf(nstrtabp + nstrtab_nextoff,
"%s", symname) + 1;
} else {
newent_len = sprintf(nstrtabp + nstrtab_nextoff,
"_$$hide$$ %s %s", fn, symname) + 1;
}
nstrtab_nextoff += newent_len;
}
strtabshdr->sh_size = htoxew(nstrtab_nextoff);
/*
* update section header table in ascending order of offset
*/
for (i = strtabidx + 1; i < shnum; i++) {
Elf_Off off, align;
off = xewtoh(layoutp[i - 1].shdr->sh_offset) +
xewtoh(layoutp[i - 1].shdr->sh_size);
align = xewtoh(layoutp[i].shdr->sh_addralign);
off = (off + (align - 1)) & ~(align - 1);
layoutp[i].shdr->sh_offset = htoxew(off);
}
/*
* write data to the file in descending order of offset
*/
for (i = shnum; i-- != 0;) {
if (layoutp[i].shdr == strtabshdr) {
/* new string table */
buf = nstrtabp;
} else
buf = layoutp[i].bufp;
if (layoutp[i].shdr == &shdrshdr ||
layoutp[i].shdr == symtabshdr || i >= strtabidx) {
if (buf == NULL)
goto bad;
/*
* update the offset of section header table in elf
* header if needed.
*/
if (layoutp[i].shdr == &shdrshdr &&
ehdr.e_shoff != shdrshdr.sh_offset) {
ehdr.e_shoff = shdrshdr.sh_offset;
off = offsetof(Elf_Ehdr, e_shoff);
size = sizeof(Elf_Off);
if ((size_t)xwriteatoff(fd, &ehdr.e_shoff, off, size,
fn) != size)
goto bad;
}
off = xewtoh(layoutp[i].shdr->sh_offset);
size = xewtoh(layoutp[i].shdr->sh_size);
if ((size_t)xwriteatoff(fd, buf, off, size, fn) != size)
goto bad;
}
}
out:
if (layoutp != NULL) {
for (i = 0; i < shnum; i++) {
if (layoutp[i].bufp != NULL)
free(layoutp[i].bufp);
}
free(layoutp);
}
free(nstrtabp);
return (rv);
bad:
rv = 1;
goto out;
}
/*
* elf to a.out converter for freebsd/sparc64 bootblocks.
*/
int
main(int ac, char **av)
{
Elf64_Half phentsize;
Elf64_Half machine;
Elf64_Half phnum;
Elf64_Xword filesz;
Elf64_Xword memsz;
Elf64_Addr entry;
Elf64_Off offset;
Elf64_Off phoff;
Elf64_Word type;
unsigned char data;
struct stat sb;
struct exec a;
Elf64_Phdr *p;
Elf64_Ehdr *e;
void *v;
int efd;
int fd;
int c;
int i;
fd = STDIN_FILENO;
while ((c = getopt(ac, av, "o:")) != -1)
switch (c) {
case 'o':
if ((fd = open(optarg, O_CREAT|O_RDWR, 0644)) < 0)
err(1, "%s", optarg);
break;
case '?':
default:
usage();
}
ac -= optind;
av += optind;
if (ac == 0)
usage();
if ((efd = open(*av, O_RDONLY)) < 0 || fstat(efd, &sb) < 0)
err(1, NULL);
v = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, efd, 0);
if ((e = v) == MAP_FAILED)
err(1, NULL);
if (!IS_ELF(*e))
errx(1, "not an elf file");
if (e->e_ident[EI_CLASS] != ELFCLASS64)
errx(1, "wrong class");
data = e->e_ident[EI_DATA];
if (data != ELFDATA2MSB && data != ELFDATA2LSB)
errx(1, "wrong data format");
if (e->e_ident[EI_VERSION] != EV_CURRENT)
errx(1, "wrong elf version");
machine = xe16toh(e->e_machine);
if (machine != EM_SPARCV9 && machine != EM_ALPHA)
errx(1, "wrong machine type");
phentsize = xe16toh(e->e_phentsize);
if (phentsize != sizeof(*p))
errx(1, "phdr size mismatch");
entry = xe64toh(e->e_entry);
phoff = xe64toh(e->e_phoff);
phnum = xe16toh(e->e_phnum);
p = (Elf64_Phdr *)((char *)e + phoff);
bzero(&a, sizeof(a));
for (i = 0; i < phnum; i++) {
type = xe32toh(p[i].p_type);
switch (type) {
case PT_LOAD:
if (a.a_magic != 0)
errx(1, "too many loadable segments");
filesz = xe64toh(p[i].p_filesz);
memsz = xe64toh(p[i].p_memsz);
offset = xe64toh(p[i].p_offset);
a.a_magic = htoxe32(A_MAGIC);
a.a_text = htoxe32(filesz);
a.a_bss = htoxe32(memsz - filesz);
a.a_entry = htoxe32(entry);
if (write(fd, &a, sizeof(a)) != sizeof(a) ||
write(fd, (char *)e + offset, filesz) != (ssize_t)filesz)
err(1, NULL);
break;
default:
break;
}
}
return (0);
}
