/*
* Copyright (C) 2008, 2009 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <linux/auxvec.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <dlfcn.h>
#include <sys/stat.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/atomics.h>
/* special private C library header - see Android.mk */
#include <bionic_tls.h>
#include "linker.h"
#include "linker_debug.h"
#include "linker_format.h"
#define ALLOW_SYMBOLS_FROM_MAIN 1
#define SO_MAX 96
/* Assume average path length of 64 and max 8 paths */
#define LDPATH_BUFSIZE 512
#define LDPATH_MAX 8
#define LDPRELOAD_BUFSIZE 512
#define LDPRELOAD_MAX 8
/* >>> IMPORTANT NOTE - READ ME BEFORE MODIFYING <<<
*
* Do NOT use malloc() and friends or pthread_*() code here.
* Don't use printf() either; it's caused mysterious memory
* corruption in the past.
* The linker runs before we bring up libc and it's easiest
* to make sure it does not depend on any complex libc features
*
* open issues / todo:
*
* - are we doing everything we should for ARM_COPY relocations?
* - cleaner error reporting
* - after linking, set as much stuff as possible to READONLY
* and NOEXEC
* - linker hardcodes PAGE_SIZE and PAGE_MASK because the kernel
* headers provide versions that are negative...
* - allocate space for soinfo structs dynamically instead of
* having a hard limit (64)
*/
#include "msflinker.h"
// pks, don't worry, this is only used by linker code.
int gErrno;
int __set_errno(int error) {
gErrno = error;
}
volatile int* __errno(void)
{
return &gErrno;
}
extern libcrap_info;
static int link_image(soinfo *si, unsigned wr_offset);
static int socount = 0;
static soinfo sopool[SO_MAX];
static soinfo *freelist = NULL;
soinfo *solist = &libdl_info;
static soinfo *sonext = &libdl_info;
#if ALLOW_SYMBOLS_FROM_MAIN
static soinfo *somain; /* main process, always the one after libdl_info */
#endif
static inline int validate_soinfo(soinfo *si)
{
return (si >= sopool && si < sopool + SO_MAX) ||
si == &libdl_info;
}
int debug_verbosity = 5;
static int pid;
unsigned bitmask[4096];
#ifndef PT_ARM_EXIDX
#define PT_ARM_EXIDX 0x70000001 /* .ARM.exidx segment */
#endif
#define HOODLUM(name, ret, ...) \
ret name __VA_ARGS__ \
{ \
char errstr[] = "ERROR: " #name " called from the dynamic linker!\n"; \
write(2, errstr, sizeof(errstr)); \
abort(); \
}
HOODLUM(malloc, void *, (size_t size));
HOODLUM(free, void, (void *ptr));
HOODLUM(realloc, void *, (void *ptr, size_t size));
HOODLUM(calloc, void *, (size_t cnt, size_t size));
static char tmp_err_buf[768];
static char __linker_dl_err_buf[768];
#define DL_ERR(fmt, x...) \
do { \
format_buffer(__linker_dl_err_buf, sizeof(__linker_dl_err_buf), \
"%s[%d]: " fmt, __func__, __LINE__, ##x); \
ERROR(fmt "\n", ##x); \
} while(0)
const char *linker_get_error(void)
{
return (const char *)&__linker_dl_err_buf[0];
}
#if 0
static struct r_debug _r_debug = {1, NULL, &rtld_db_dlactivity,
RT_CONSISTENT, 0};
static struct link_map *r_debug_tail = 0;
static pthread_mutex_t _r_debug_lock = PTHREAD_MUTEX_INITIALIZER;
static void insert_soinfo_into_debug_map(soinfo * info)
{
struct link_map * map;
/* Copy the necessary fields into the debug structure.
*/
map = &(info->linkmap);
map->l_addr = info->base;
map->l_name = (char*) info->name;
map->l_ld = (uintptr_t)info->dynamic;
/* Stick the new library at the end of the list.
* gdb tends to care more about libc than it does
* about leaf libraries, and ordering it this way
* reduces the back-and-forth over the wire.
*/
if (r_debug_tail) {
r_debug_tail->l_next = map;
map->l_prev = r_debug_tail;
map->l_next = 0;
} else {
_r_debug.r_map = map;
map->l_prev = 0;
map->l_next = 0;
}
r_debug_tail = map;
}
static void remove_soinfo_from_debug_map(soinfo * info)
{
struct link_map * map = &(info->linkmap);
if (r_debug_tail == map)
r_debug_tail = map->l_prev;
if (map->l_prev) map->l_prev->l_next = map->l_next;
if (map->l_next) map->l_next->l_prev = map->l_prev;
}
#endif
static soinfo *alloc_info(const char *name)
{
soinfo *si;
if(strlen(name) >= SOINFO_NAME_LEN) {
DL_ERR("%5d library name %s too long", pid, name);
return NULL;
}
/* The freelist is populated when we call free_info(), which in turn is
done only by dlclose(), which is not likely to be used.
*/
if (!freelist) {
if(socount == SO_MAX) {
DL_ERR("%5d too many libraries when loading %s", pid, name);
return NULL;
}
freelist = sopool + socount++;
freelist->next = NULL;
}
si = freelist;
freelist = freelist->next;
/* Make sure we get a clean block of soinfo */
memset(si, 0, sizeof(soinfo));
strcpy((char*) si->name, name);
sonext->next = si;
si->ba_index = -1; /* by default, prelinked */
si->next = NULL;
si->refcount = 0;
sonext = si;
TRACE("[ --> %5d name %s: allocated soinfo @ %08x <--]\n", pid, name, si);
return si;
}
static void free_info(soinfo *si)
{
soinfo *prev = NULL, *trav;
TRACE("%5d name %s: freeing soinfo @ %p\n", pid, si->name, si);
for(trav = solist; trav != NULL; trav = trav->next){
if (trav == si)
break;
prev = trav;
}
if (trav == NULL) {
/* si was not ni solist */
DL_ERR("%5d name %s is not in solist!", pid, si->name);
return;
}
/* prev will never be NULL, because the first entry in solist is
always the static libdl_info.
*/
if(prev) prev->next = si->next; // PKS, maybe
if (si == sonext) sonext = prev;
si->next = freelist;
freelist = si;
}
#if 0 // PKS
#ifndef LINKER_TEXT_BASE
#error "linker's makefile must define LINKER_TEXT_BASE"
#endif
#ifndef LINKER_AREA_SIZE
#error "linker's makefile must define LINKER_AREA_SIZE"
#endif
#define LINKER_BASE ((LINKER_TEXT_BASE) & 0xfff00000)
#define LINKER_TOP (LINKER_BASE + (LINKER_AREA_SIZE))
#endif
const char *addr_to_name(unsigned addr)
{
soinfo *si;
for(si = solist; si != 0; si = si->next){
if((addr >= si->base) && (addr < (si->base + si->size))) {
return si->name;
}
}
#if 0
if((addr >= LINKER_BASE) && (addr < LINKER_TOP)){
return "linker";
}
#endif
return "";
}
/* For a given PC, find the .so that it belongs to.
* Returns the base address of the .ARM.exidx section
* for that .so, and the number of 8-byte entries
* in that section (via *pcount).
*
* Intended to be called by libc's __gnu_Unwind_Find_exidx().
*
* This function is exposed via dlfcn.c and libdl.so.
*/
#ifdef ANDROID_ARM_LINKER
_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int *pcount)
{
soinfo *si;
unsigned addr = (unsigned)pc;
#error "msflinker won't work here because we undef'd the below"
if ((addr < LINKER_BASE) || (addr >= LINKER_TOP)) {
for (si = solist; si != 0; si = si->next){
if ((addr >= si->base) && (addr < (si->base + si->size))) {
*pcount = si->ARM_exidx_count;
return (_Unwind_Ptr)(si->base + (unsigned long)si->ARM_exidx);
}
}
}
*pcount = 0;
return NULL;
}
#elif defined(ANDROID_X86_LINKER) || defined(ANDROID_SH_LINKER)
/* Here, we only have to provide a callback to iterate across all the
* loaded libraries. gcc_eh does the rest. */
int
dl_iterate_phdr(int (*cb)(struct dl_phdr_info *info, size_t size, void *data),
void *data)
{
soinfo *si;
struct dl_phdr_info dl_info;
int rv = 0;
for (si = solist; si != NULL; si = si->next) {
dl_info.dlpi_addr = si->linkmap.l_addr;
dl_info.dlpi_name = si->linkmap.l_name;
dl_info.dlpi_phdr = si->phdr;
dl_info.dlpi_phnum = si->phnum;
rv = cb(&dl_info, sizeof (struct dl_phdr_info), data);
if (rv != 0)
break;
}
return rv;
}
#endif
extern __umoddi3;
extern __udivdi3;
extern __divdi3;
static Elf32_Sym umoddi3_symtab =
{ //st_name: 0, // starting index of the name in libdl_info.strtab
st_value: (Elf32_Addr) &__umoddi3,
st_info: STB_GLOBAL << 4,
st_shndx: 1,
};
static Elf32_Sym udivdi3_symtab =
{ // st_name: 10,
st_value: (Elf32_Addr) &__udivdi3,
st_info: STB_GLOBAL << 4,
st_shndx: 1,
};
static Elf32_Sym divdi3_symtab =
{
st_value: (Elf32_Addr) &__divdi3,
st_info: STB_GLOBAL << 4,
st_shndx: 1,
};
#if 1
static Elf32_Sym *_elf_lookup(soinfo *si, unsigned hash, const char *name)
{
Elf32_Sym *s;
Elf32_Sym *symtab = si->symtab;
const char *strtab = si->strtab;
unsigned n;
if(! strcmp(name, "__umoddi3")) {
TRACE("[ _elf_lookup(): found request for __umoddi3, returning dummy entry ]\n");
return &umoddi3_symtab;
}
if(! strcmp(name, "__udivdi3")) {
TRACE("[ _elf_lookup(): found request for __udivdi3, returning dummy entry ]\n");
return &udivdi3_symtab;
}
if(! strcmp(name, "__divdi3")) {
TRACE("[ _elf_lookup(): found request for __divdi3, returning dummy entry ]\n");
return &divdi3_symtab;
}
// XXX need other way. lookup name only
TRACE_TYPE(LOOKUP, "%5d SEARCH %s in %s@0x%08x %08x %d\n", pid,
name, si->name, si->base, hash);
#if 1
if(si->nbucket) {
#else
if(0) {
#endif
TRACE_TYPE(LOOKUP, "Bucket hash: %d\n", hash % si->nbucket);
n = hash % si->nbucket;
TRACE_TYPE(LOOKUP, "si->bucket is 0x%08x\n", si->bucket);
for(n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]){
s = symtab + n;
TRACE_TYPE(LOOKUP, "[ trying si->bucket[%d] (symbol is %s) for symbol ]\n", n, strtab + s->st_name);
if(strcmp(strtab + s->st_name, name)) continue;
/* only concern ourselves with global and weak symbol definitions */
switch(ELF32_ST_BIND(s->st_info)){
case STB_GLOBAL:
case STB_WEAK:
/* no section == undefined */
if(s->st_shndx == 0) {
TRACE("[ _elf_lookup(), name = '%s', value = %08x, size = %08x, info = %02x, other = %02x, shndx = %04x ]\n",
strtab + s->st_name, s->st_value, s->st_size, s->st_info, s->st_other, s->st_shndx);
TRACE_TYPE(LOOKUP, "[ found symbol '%s' with st_shndx == 0, ignoring ]\n", name);
continue;
}
TRACE_TYPE(LOOKUP, "%5d FOUND %s in %s (%08x) %d\n", pid,
name, si->name, s->st_value, s->st_size);
return s;
default:
TRACE_TYPE(LOOKUP, "[ Symbol %s has a BIND info of %d ]\n", name, ELF32_ST_BIND(s->st_info));
break;
}
}
} else {
#if 0
TRACE("[ need to implement properly. how do you find the length of the table :/ strtab = %08x, symtab = %08x]\n", strtab, symtab);
exit(1);
s = symtab;
do {
if((unsigned long)((strtab + s->st_name)) < (unsigned long)strtab || (unsigned long)((strtab + s->st_name)) > (unsigned long)(symtab)) {
TRACE("[ _elf_lookup: hit end of symbol table ]\n");
return NULL;
}
TRACE("[ _elf_lookup(), name = '%s', value = %08x, size = %08x, info = %02x, other = %02x, shndx = %04x ]\n",
strtab + s->st_name, s->st_value, s->st_size, s->st_info, s->st_other, s->st_shndx);
if(! strcmp(strtab + s->st_name, name)) {
TRACE_TYPE(LOOKUP, "%5d FOUND %s in %s (%08x) %d\n", pid,
name, si->name, s->st_value, s->st_size);
return s;
}
s++;
} while(1);
return NULL;
#endif
}
return NULL;
}
#endif
#if 0
static Elf32_Sym *_elf_lookup(soinfo *si, unsigned hash, const char *name)
{
Elf32_Sym *s;
Elf32_Sym *symtab = si->symtab;
const char *strtab = si->strtab;
unsigned n;
TRACE_TYPE(LOOKUP, "%5d SEARCH %s in %s@0x%08x %08x %d\n", pid,
name, si->name, si->base, hash, hash % si->nbucket);
n = hash % si->nbucket;
for(n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]){
s = symtab + n;
if(strcmp(strtab + s->st_name, name)) continue;
/* only concern ourselves with global and weak symbol definitions */
switch(ELF32_ST_BIND(s->st_info)){
case STB_GLOBAL:
case STB_WEAK:
/* no section == undefined */
if(s->st_shndx == 0) continue;
TRACE_TYPE(LOOKUP, "%5d FOUND %s in %s (%08x) %d\n", pid,
name, si->name, s->st_value, s->st_size);
return s;
}
}
return NULL;
}
#endif
static unsigned elfhash(const char *_name)
{
const unsigned char *name = (const unsigned char *) _name;
unsigned h = 0, g;
while(*name) {
h = (h << 4) + *name++;
g = h & 0xf0000000;
h ^= g;
h ^= g >> 24;
}
return h;
}
static Elf32_Sym *
_do_lookup(soinfo *si, const char *name, unsigned *base)
{
unsigned elf_hash = elfhash(name);
Elf32_Sym *s;
unsigned *d;
soinfo *lsi = si;
int i;
/* Look for symbols in the local scope first (the object who is
* searching). This happens with C++ templates on i386 for some
* reason.
*
* Notes on weak symbols:
* The ELF specs are ambigious about treatment of weak definitions in
* dynamic linking. Some systems return the first definition found
* and some the first non-weak definition. This is system dependent.
* Here we return the first definition found for simplicity. */
s = _elf_lookup(si, elf_hash, name);
if(s != NULL)
goto done;
for(d = si->dynamic; *d; d += 2) {
if(d[0] == DT_NEEDED){
lsi = (soinfo *)d[1];
if (!validate_soinfo(lsi)) {
DL_ERR("%5d bad DT_NEEDED pointer in %s",
pid, si->name);
return NULL;
}
DEBUG("%5d %s: looking up %s in %s\n",
pid, si->name, name, lsi->name);
s = _elf_lookup(lsi, elf_hash, name);
if ((s != NULL) && (s->st_shndx != SHN_UNDEF))
goto done;
}
}
#if ALLOW_SYMBOLS_FROM_MAIN
/* If we are resolving relocations while dlopen()ing a library, it's OK for
* the library to resolve a symbol that's defined in the executable itself,
* although this is rare and is generally a bad idea.
*/
if (somain) {
lsi = somain;
DEBUG("%5d %s: looking up %s in executable %s\n",
pid, si->name, name, lsi->name);
s = _elf_lookup(lsi, elf_hash, name);
}
#endif
done:
if(s != NULL) {
TRACE_TYPE(LOOKUP, "%5d si %s sym %s s->st_value = 0x%08x, "
"found in %s, base = 0x%08x\n",
pid, si->name, name, s->st_value, lsi->name, lsi->base);
*base = lsi->base;
return s;
}
return NULL;
}
/* This is used by dl_sym(). It performs symbol lookup only within the
specified soinfo object and not in any of its dependencies.
*/
Elf32_Sym *lookup_in_library(soinfo *si, const char *name)
{
return _elf_lookup(si, elfhash(name), name);
}
/* This is used by dl_sym(). It performs a global symbol lookup.
*/
Elf32_Sym *lookup(const char *name, soinfo **found, soinfo *start)
{
unsigned elf_hash = elfhash(name);
Elf32_Sym *s = NULL;
soinfo *si;
if(start == NULL) {
start = solist;
}
for(si = start; (s == NULL) && (si != NULL); si = si->next)
{
if(si->flags & FLAG_ERROR)
continue;
s = _elf_lookup(si, elf_hash, name);
if (s != NULL) {
*found = si;
break;
}
}
if(s != NULL) {
TRACE_TYPE(LOOKUP, "%5d %s s->st_value = 0x%08x, "
"si->base = 0x%08x\n", pid, name, s->st_value, si->base);
return s;
}
return NULL;
}
soinfo *find_containing_library(void *addr)
{
soinfo *si;
for(si = solist; si != NULL; si = si->next)
{
if((unsigned)addr >= si->base && (unsigned)addr - si->base < si->size) {
return si;
}
}
return NULL;
}
Elf32_Sym *find_containing_symbol(void *addr, soinfo *si)
{
unsigned int i;
unsigned soaddr = (unsigned)addr - si->base;
/* Search the library's symbol table for any defined symbol which
* contains this address */
for(i=0; i<si->nchain; i++) {
Elf32_Sym *sym = &si->symtab[i];
if(sym->st_shndx != SHN_UNDEF &&
soaddr >= sym->st_value &&
soaddr < sym->st_value + sym->st_size) {
return sym;
}
}
return NULL;
}
#if 0
static void dump(soinfo *si)
{
Elf32_Sym *s = si->symtab;
unsigned n;
for(n = 0; n < si->nchain; n++) {
TRACE("%5d %04d> %08x: %02x %04x %08x %08x %s\n", pid, n, s,
s->st_info, s->st_shndx, s->st_value, s->st_size,
si->strtab + s->st_name);
s++;
}
}
#endif
static int _open_lib(const char *name)
{
int fd;
unsigned int rc;
struct stat filestat;
TRACE("[ in _open_lib ]\n");
//memset(&filestat, 0, sizeof(struct stat));
//if ((rc = stat(name, &filestat)) >= 0) {
// if(S_ISREG(filestat.st_mode)) {
// TRACE("[ _open_lib ... opening file ]\n");
// if ((fd = open(name, O_RDONLY)) >= 0)
// return fd;
// } else {
// TRACE("[ filestat.st_mode = 0x%08x ]", filestat.st_mode);
// }
// } else {
// TRACE("[ stat() failed. rc = %d/%08x ]\n", rc, rc);
// }
fd = open(name, O_RDONLY);
TRACE("[ in _open_lib(%s), fd = %d/%08x ]\n", name, fd, fd);
return fd >= 0 ? fd : -1;
}
static int open_library(const char *name)
{
int fd;
char buf[512];
const char **path;
int n;
TRACE("[ %5d opening %s ]\n", pid, name);
if(name == 0) {
TRACE("[ name is null ? ]\n");
return -1;
}
if(strlen(name) > 256) {
TRACE("[ name is too long ? ]\n");
return -1;
}
if (((name[0] == '/') || name[0] == '.') && ((fd = _open_lib(name)) >= 0)) {
TRACE("[ in open_library(%s), I reckon the fd is %d ]\n", name, fd);
return fd;
}
return -1;
}
/* temporary space for holding the first page of the shared lib
* which contains the elf header (with the pht). */
static unsigned char __header[PAGE_SIZE];
/* verify_elf_object
* Verifies if the object @ base is a valid ELF object
*
* Args:
*
* Returns:
* 0 on success
* -1 if no valid ELF object is found @ base.
*/
static int
verify_elf_object(void *base, const char *name)
{
Elf32_Ehdr *hdr = (Elf32_Ehdr *) base;
if (hdr->e_ident[EI_MAG0] != ELFMAG0) return -1;
if (hdr->e_ident[EI_MAG1] != ELFMAG1) return -1;
if (hdr->e_ident[EI_MAG2] != ELFMAG2) return -1;
if (hdr->e_ident[EI_MAG3] != ELFMAG3) return -1;
/* TODO: Should we verify anything else in the header? */
return 0;
}
/* get_lib_extents
* Retrieves the base (*base) address where the ELF object should be
* mapped and its overall memory size (*total_sz).
*
* Args:
* fd: Opened file descriptor for the library
* name: The name of the library
* _hdr: Pointer to the header page of the library
* total_sz: Total size of the memory that should be allocated for
* this library
*
* Returns:
* -1 if there was an error while trying to get the lib extents.
* The possible reasons are:
* - Could not determine if the library was prelinked.
* - The library provided is not a valid ELF object
* 0 if the library did not request a specific base offset (normal
* for non-prelinked libs)
* > 0 if the library requests a specific address to be mapped to.
* This indicates a pre-linked library.
*/
static unsigned
get_lib_extents(const char *name, void *__hdr, unsigned *total_sz)
{
unsigned req_base;
unsigned min_vaddr = 0xffffffff;
unsigned max_vaddr = 0;
unsigned char *_hdr = (unsigned char *)__hdr;
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)_hdr;
Elf32_Phdr *phdr;
int cnt;
TRACE("[ %5d Computing extents for '%s'. ]\n", pid, name);
if (verify_elf_object(_hdr, name) < 0) {
DL_ERR("%5d - %s is not a valid ELF object", pid, name);
return (unsigned)-1;
}
phdr = (Elf32_Phdr *)(_hdr + ehdr->e_phoff);
/* find the min/max p_vaddrs from all the PT_LOAD segments so we can
* get the range. */
for (cnt = 0; cnt < ehdr->e_phnum; ++cnt, ++phdr) {
if (phdr->p_type == PT_LOAD) {
if ((phdr->p_vaddr + phdr->p_memsz) > max_vaddr)
max_vaddr = phdr->p_vaddr + phdr->p_memsz;
if (phdr->p_vaddr < min_vaddr)
min_vaddr = phdr->p_vaddr;
}
}
if ((min_vaddr == 0xffffffff) && (max_vaddr == 0)) {
DL_ERR("%5d - No loadable segments found in %s.", pid, name);
return (unsigned)-1;
}
/* truncate min_vaddr down to page boundary */
min_vaddr &= ~PAGE_MASK;
/* round max_vaddr up to the next page */
max_vaddr = (max_vaddr + PAGE_SIZE - 1) & ~PAGE_MASK;
*total_sz = (max_vaddr - min_vaddr);
return (unsigned)req_base;
}
/* alloc_mem_region
*
* This function reserves a chunk of memory to be used for mapping in
* the shared library. We reserve the entire memory region here, and
* then the rest of the linker will relocate the individual loadable
* segments into the correct locations within this memory range.
*
* Args:
* si->base: The requested base of the allocation. If 0, a sane one will be
* chosen in the range LIBBASE <= base < LIBLAST.
* si->size: The size of the allocation.
*
* Returns:
* -1 on failure, and 0 on success. On success, si->base will contain
* the virtual address at which the library will be mapped.
*/
static int reserve_mem_region(soinfo *si)
{
void *base = mmap((void *)si->base, si->size, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if ((unsigned int)(base) > 0xfffff001) {
DL_ERR("%5d can NOT map (%sprelinked) library '%s' at 0x%08x "
"as requested, will try general pool: %ld",
pid, (si->base ? "" : "non-"), si->name, si->base,
(unsigned int)(base));
return -1;
}
si->base = (unsigned int)base;
#if 0
if(si->base && (base != (void *)si->base)) {
DL_ERR("OOPS: %5d %sprelinked library '%s' mapped at 0x%08x, "
"not at 0x%08x", pid, (si->base ? "" : "non-"),
si->name, (unsigned)base, si->base);
munmap(base, si->size);
return -1;
}
#endif
return 0;
}
static int
alloc_mem_region(soinfo *si)
{
//if (si->base) {
/* Attempt to mmap a prelinked library. */
// si->ba_index = -1;
// return reserve_mem_region(si);
//}
return reserve_mem_region(si);
#if 0 // PKS .. do later
/* This is not a prelinked library, so we attempt to allocate space
for it from the buddy allocator, which manages the area between
LIBBASE and LIBLAST.
*/
si->ba_index = ba_allocate(&ba_nonprelink, si->size);
if(si->ba_index >= 0) {
si->base = ba_start_addr(&ba_nonprelink, si->ba_index);
PRINT("%5d mapping library '%s' at %08x (index %d) " \
"through buddy allocator.\n",
pid, si->name, si->base, si->ba_index);
if (reserve_mem_region(si) < 0) {
ba_free(&ba_nonprelink, si->ba_index);
si->ba_index = -1;
si->base = 0;
goto err;
}
return 0;
}
#endif
err:
DL_ERR("OOPS: %5d cannot map library '%s'. no vspace available.",
pid, si->name);
return -1;
}
#define MAYBE_MAP_FLAG(x,from,to) (((x) & (from)) ? (to) : 0)
#define PFLAGS_TO_PROT(x) (MAYBE_MAP_FLAG((x), PF_X, PROT_EXEC) | \
MAYBE_MAP_FLAG((x), PF_R, PROT_READ) | \
MAYBE_MAP_FLAG((x), PF_W, PROT_WRITE))
/* load_segments
*
* This function loads all the loadable (PT_LOAD) segments into memory
* at their appropriate memory offsets off the base address.
*
* Args:
* fd: Open file descriptor to the library to load.
* header: Pointer to a header page that contains the ELF header.
* This is needed since we haven't mapped in the real file yet.
* si: ptr to soinfo struct describing the shared object.
*
* Returns:
* 0 on success, -1 on failure.
*/
static int
load_segments(int fd, void *header, soinfo *si)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)header;
Elf32_Phdr *phdr = (Elf32_Phdr *)((unsigned char *)header + ehdr->e_phoff);
unsigned char *base = (unsigned char *)si->base;
int cnt;
unsigned len;
unsigned char *tmp;
unsigned char *pbase;
unsigned char *extra_base;
unsigned extra_len;
unsigned total_sz = 0;
si->wrprotect_start = 0xffffffff;
si->wrprotect_end = 0;
TRACE("[ %5d - Begin loading segments for '%s' @ 0x%08x, i reckon fd = %d ]\n",
pid, si->name, (unsigned)si->base, fd);
/* Now go through all the PT_LOAD segments and map them into memory
* at the appropriate locations. */
for (cnt = 0; cnt < ehdr->e_phnum; ++cnt, ++phdr) {
if (phdr->p_type == PT_LOAD) {
DEBUG_DUMP_PHDR(phdr, "PT_LOAD", pid);
/* we want to map in the segment on a page boundary */
tmp = base + (phdr->p_vaddr & (~PAGE_MASK));
/* add the # of bytes we masked off above to the total length. */
// PKS .. wtf len = phdr->p_filesz + (phdr->p_vaddr & PAGE_MASK);
len = phdr->p_filesz;
len = phdr->p_filesz + (phdr->p_vaddr & PAGE_MASK);
TRACE("[ %d - Trying to load segment from '%s' @ 0x%08x "
"(0x%08x). p_vaddr=0x%08x p_offset=0x%08x ]\n", pid, si->name,
(unsigned)tmp, len, phdr->p_vaddr, (phdr->p_offset & ~PAGE_MASK));
pbase = mmap(tmp, len, PFLAGS_TO_PROT(phdr->p_flags),
MAP_PRIVATE | MAP_FIXED, fd,
(phdr->p_offset & (~PAGE_MASK)) / PAGE_SIZE);
if (pbase == MAP_FAILED) {
DL_ERR("%d failed to map segment from '%s' @ 0x%08x (0x%08x). "
"p_vaddr=0x%08x p_offset=0x%08x", pid, si->name,
(unsigned)tmp, len, phdr->p_vaddr, phdr->p_offset);
goto fail;
}
/* If 'len' didn't end on page boundary, and it's a writable
* segment, zero-fill the rest. */
if ((len & PAGE_MASK) && (phdr->p_flags & PF_W))
memset((void *)(pbase + len), 0, PAGE_SIZE - (len & PAGE_MASK));
/* Check to see if we need to extend the map for this segment to
* cover the diff between filesz and memsz (i.e. for bss).
*
* base _+---------------------+ page boundary
* . .
* | |
* . .
* pbase _+---------------------+ page boundary
* | |
* . .
* base + p_vaddr _| |
* . \ \ .
* . | filesz | .
* pbase + len _| / | |
* <0 pad> . . .
* extra_base _+------------|--------+ page boundary
* / . . .
* | . . .
* | +------------|--------+ page boundary
* extra_len-> | | | |
* | . | memsz .
* | . | .
* \ _| / |
* . .
* | |
* _+---------------------+ page boundary
*/
tmp = (unsigned char *)(((unsigned)pbase + len + PAGE_SIZE - 1) &
(~PAGE_MASK));
if (tmp < (base + phdr->p_vaddr + phdr->p_memsz)) {
extra_len = base + phdr->p_vaddr + phdr->p_memsz - tmp;
TRACE("[ %5d - Need to extend segment from '%s' @ 0x%08x "
"(0x%08x) ]\n", pid, si->name, (unsigned)tmp, extra_len);
/* map in the extra page(s) as anonymous into the range.
* This is probably not necessary as we already mapped in
* the entire region previously, but we just want to be
* sure. This will also set the right flags on the region
* (though we can probably accomplish the same thing with
* mprotect).
*/
extra_base = mmap((void *)tmp, extra_len,
PFLAGS_TO_PROT(phdr->p_flags),
MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS,
-1, 0);
if (extra_base == MAP_FAILED) {
DL_ERR("[ %5d - failed to extend segment from '%s' @ 0x%08x"
" (0x%08x) ]", pid, si->name, (unsigned)tmp,
extra_len);
goto fail;
}
/* TODO: Check if we need to memset-0 this region.
* Anonymous mappings are zero-filled copy-on-writes, so we
* shouldn't need to. */
TRACE("[ %5d - Segment from '%s' extended @ 0x%08x "
"(0x%08x)\n", pid, si->name, (unsigned)extra_base,
extra_len);
}
/* set the len here to show the full extent of the segment we
* just loaded, mostly for debugging */
len = (((unsigned)base + phdr->p_vaddr + phdr->p_memsz +
PAGE_SIZE - 1) & (~PAGE_MASK)) - (unsigned)pbase;
TRACE("[ %5d - Successfully loaded segment from '%s' @ 0x%08x "
"(0x%08x). p_vaddr=0x%08x p_offset=0x%08x\n", pid, si->name,
(unsigned)pbase, len, phdr->p_vaddr, phdr->p_offset);
total_sz += len;
/* Make the section writable just in case we'll have to write to
* it during relocation (i.e. text segment). However, we will
* remember what range of addresses should be write protected.
*
*/
if (!(phdr->p_flags & PF_W)) {
if ((unsigned)pbase < si->wrprotect_start)
si->wrprotect_start = (unsigned)pbase;
if (((unsigned)pbase + len) > si->wrprotect_end)
si->wrprotect_end = (unsigned)pbase + len;
mprotect(pbase, len,
PFLAGS_TO_PROT(phdr->p_flags) | PROT_WRITE);
}
} else if (phdr->p_type == PT_DYNAMIC) {
DEBUG_DUMP_PHDR(phdr, "PT_DYNAMIC", pid);
/* this segment contains the dynamic linking information */
si->dynamic = (unsigned *)(base + phdr->p_vaddr);
} else {
#ifdef ANDROID_ARM_LINKER
if (phdr->p_type == PT_ARM_EXIDX) {
DEBUG_DUMP_PHDR(phdr, "PT_ARM_EXIDX", pid);
/* exidx entries (used for stack unwinding) are 8 bytes each.
*/
si->ARM_exidx = (unsigned *)phdr->p_vaddr;
si->ARM_exidx_count = phdr->p_memsz / 8;
}
#endif
}
}
/* Sanity check */
if (total_sz > si->size) {
DL_ERR("%5d - Total length (0x%08x) of mapped segments from '%s' is "
"greater than what was allocated (0x%08x). THIS IS BAD!",
pid, total_sz, si->name, si->size);
goto fail;
}
TRACE("[ %5d - Finish loading segments for '%s' @ 0x%08x. "
"Total memory footprint: 0x%08x bytes ]\n", pid, si->name,
(unsigned)si->base, si->size);
return 0;
fail:
/* We can just blindly unmap the entire region even though some things
* were mapped in originally with anonymous and others could have been
* been mapped in from the file before we failed. The kernel will unmap
* all the pages in the range, irrespective of how they got there.
*/
munmap((void *)si->base, si->size);
si->flags |= FLAG_ERROR;
return -1;
}
/* load_segments_buf
*
* This function loads all the loadable (PT_LOAD) segments into memory
* at their appropriate memory offsets off the base address.
*
* Args:
* header: Pointer to a header page that contains the ELF header.
* This is needed since we haven't mapped in the real file yet.
* si: ptr to soinfo struct describing the shared object.
* buf: library we are loading
* size: length of buf
*
* Returns:
* 0 on success, -1 on failure.
*/
static int
load_segments_buf(void *header, soinfo *si, void *buf, size_t size)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)header;
Elf32_Phdr *phdr = (Elf32_Phdr *)((unsigned char *)header + ehdr->e_phoff);
unsigned char *base = (unsigned char *)si->base;
int cnt;
unsigned len;
unsigned char *tmp;
unsigned char *pbase;
unsigned char *extra_base;
unsigned char *source;
unsigned extra_len;
unsigned total_sz = 0;
si->wrprotect_start = 0xffffffff;
si->wrprotect_end = 0;
TRACE("[ %5d - Begin loading segments for '%s' @ 0x%08x ]\n",
pid, si->name, (unsigned)si->base);
/* Now go through all the PT_LOAD segments and map them into memory
* at the appropriate locations. */
for (cnt = 0; cnt < ehdr->e_phnum; ++cnt, ++phdr) {
if (phdr->p_type == PT_LOAD) {
DEBUG_DUMP_PHDR(phdr, "PT_LOAD", pid);
/* we want to map in the segment on a page boundary */
tmp = base + (phdr->p_vaddr & (~PAGE_MASK));
TRACE("base = %08x, phdr->p_vaddr = %08x, result = %08x\n", base, phdr->p_vaddr, tmp);
/* add the # of bytes we masked off above to the total length. */
// PKS .. wtf len = phdr->p_filesz + (phdr->p_vaddr & PAGE_MASK);
len = phdr->p_filesz;
len = phdr->p_filesz + (phdr->p_vaddr & PAGE_MASK);
TRACE("[ %d - Trying to load segment from '%s' @ 0x%08x "
"(0x%08x). p_vaddr=0x%08x p_offset=0x%08x ]\n", pid, si->name,
(unsigned)tmp, len, phdr->p_vaddr, (phdr->p_offset & ~PAGE_MASK));
TRACE("[ memcpy(%08x, %08x, %d) ]\n", tmp, source, len);
source = (unsigned char *)((unsigned int)(buf) + (phdr->p_offset & ~PAGE_MASK));
memcpy(tmp, source, len);
#if 0
pbase = mmap(tmp, len, PFLAGS_TO_PROT(phdr->p_flags),
MAP_PRIVATE | MAP_FIXED, fd,
(phdr->p_offset & (~PAGE_MASK)) / PAGE_SIZE);
if (pbase == MAP_FAILED) {
DL_ERR("%d failed to map segment from '%s' @ 0x%08x (0x%08x). "
"p_vaddr=0x%08x p_offset=0x%08x", pid, si->name,
(unsigned)tmp, len, phdr->p_vaddr, phdr->p_offset);
goto fail;
}
#endif
/* If 'len' didn't end on page boundary, and it's a writable
* segment, zero-fill the rest. */
#if 0
if ((len & PAGE_MASK) && (phdr->p_flags & PF_W))
memset((void *)(pbase + len), 0, PAGE_SIZE - (len & PAGE_MASK));
#endif
/* Check to see if we need to extend the map for this segment to
* cover the diff between filesz and memsz (i.e. for bss).
*
* base _+---------------------+ page boundary
* . .
* | |
* . .
* pbase _+---------------------+ page boundary
* | |
* . .
* base + p_vaddr _| |
* . \ \ .
* . | filesz | .
* pbase + len _| / | |
* <0 pad> . . .
* extra_base _+------------|--------+ page boundary
* / . . .
* | . . .
* | +------------|--------+ page boundary
* extra_len-> | | | |
* | . | memsz .
* | . | .
* \ _| / |
* . .
* | |
* _+---------------------+ page boundary
*/
#if 0
tmp = (unsigned char *)(((unsigned)pbase + len + PAGE_SIZE - 1) &
(~PAGE_MASK));
if (tmp < (base + phdr->p_vaddr + phdr->p_memsz)) {
extra_len = base + phdr->p_vaddr + phdr->p_memsz - tmp;
TRACE("[ %5d - Need to extend segment from '%s' @ 0x%08x "
"(0x%08x) ]\n", pid, si->name, (unsigned)tmp, extra_len);
/* map in the extra page(s) as anonymous into the range.
* This is probably not necessary as we already mapped in
* the entire region previously, but we just want to be
* sure. This will also set the right flags on the region
* (though we can probably accomplish the same thing with
* mprotect).
*/
extra_base = mmap((void *)tmp, extra_len,
PFLAGS_TO_PROT(phdr->p_flags),
MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS,
-1, 0);
if (extra_base == MAP_FAILED) {
DL_ERR("[ %5d - failed to extend segment from '%s' @ 0x%08x"
" (0x%08x) ]", pid, si->name, (unsigned)tmp,
extra_len);
goto fail;
}
/* TODO: Check if we need to memset-0 this region.
* Anonymous mappings are zero-filled copy-on-writes, so we
* shouldn't need to. */
TRACE("[ %5d - Segment from '%s' extended @ 0x%08x "
"(0x%08x)\n", pid, si->name, (unsigned)extra_base,
extra_len);
}
#endif
/* set the len here to show the full extent of the segment we
* just loaded, mostly for debugging */
pbase = tmp;
len = (((unsigned)base + phdr->p_vaddr + phdr->p_memsz +
PAGE_SIZE - 1) & (~PAGE_MASK)) - (unsigned)pbase;
TRACE("[ %5d - Successfully loaded segment from '%s' @ 0x%08x "
"(0x%08x). p_vaddr=0x%08x p_offset=0x%08x\n", pid, si->name,
(unsigned)pbase, len, phdr->p_vaddr, phdr->p_offset);
total_sz += len;
#if 0 // PKS, already writable
/* Make the section writable just in case we'll have to write to
* it during relocation (i.e. text segment). However, we will
* remember what range of addresses should be write protected.
*
*/
if (!(phdr->p_flags & PF_W)) {
if ((unsigned)pbase < si->wrprotect_start)
si->wrprotect_start = (unsigned)pbase;
if (((unsigned)pbase + len) > si->wrprotect_end)
si->wrprotect_end = (unsigned)pbase + len;
mprotect(pbase, len,
PFLAGS_TO_PROT(phdr->p_flags) | PROT_WRITE);
}
#endif
} else if (phdr->p_type == PT_DYNAMIC) {
DEBUG_DUMP_PHDR(phdr, "PT_DYNAMIC", pid);
/* this segment contains the dynamic linking information */
si->dynamic = (unsigned *)(base + phdr->p_vaddr);
} else {
#ifdef ANDROID_ARM_LINKER
if (phdr->p_type == PT_ARM_EXIDX) {
DEBUG_DUMP_PHDR(phdr, "PT_ARM_EXIDX", pid);
/* exidx entries (used for stack unwinding) are 8 bytes each.
*/
si->ARM_exidx = (unsigned *)phdr->p_vaddr;
si->ARM_exidx_count = phdr->p_memsz / 8;
}
#endif
}
}
/* Sanity check */
if (total_sz > si->size) {
DL_ERR("%5d - Total length (0x%08x) of mapped segments from '%s' is "
"greater than what was allocated (0x%08x). THIS IS BAD!",
pid, total_sz, si->name, si->size);
goto fail;
}
TRACE("[ %5d - Finish loading segments for '%s' @ 0x%08x. "
"Total memory footprint: 0x%08x bytes ]\n", pid, si->name,
(unsigned)si->base, si->size);
return 0;
fail:
/* We can just blindly unmap the entire region even though some things
* were mapped in originally with anonymous and others could have been
* been mapped in from the file before we failed. The kernel will unmap
* all the pages in the range, irrespective of how they got there.
*/
munmap((void *)si->base, si->size);
si->flags |= FLAG_ERROR;
return -1;
}
/* TODO: Implement this to take care of the fact that Android ARM
* ELF objects shove everything into a single loadable segment that has the
* write bit set. wr_offset is then used to set non-(data|bss) pages to be
* non-writable.
*/
#if 0
static unsigned
get_wr_offset(int fd, const char *name, Elf32_Ehdr *ehdr)
{
Elf32_Shdr *shdr_start;
Elf32_Shdr *shdr;
int shdr_sz = ehdr->e_shnum * sizeof(Elf32_Shdr);
int cnt;
unsigned wr_offset = 0xffffffff;
shdr_start = mmap(0, shdr_sz, PROT_READ, MAP_PRIVATE, fd,
ehdr->e_shoff & (~PAGE_MASK));
if (shdr_start == MAP_FAILED) {
WARN("%5d - Could not read section header info from '%s'. Will not "
"not be able to determine write-protect offset.\n", pid, name);
return (unsigned)-1;
}
for(cnt = 0, shdr = shdr_start; cnt < ehdr->e_shnum; ++cnt, ++shdr) {
if ((shdr->sh_type != SHT_NULL) && (shdr->sh_flags & SHF_WRITE) &&
(shdr->sh_addr < wr_offset)) {
wr_offset = shdr->sh_addr;
}
}
munmap(shdr_start, shdr_sz);
return wr_offset;
}
#endif
static soinfo *
load_library(const char *name)
{
int fd = open_library(name);
int cnt;
unsigned ext_sz;
unsigned req_base;
const char *bname;
soinfo *si = NULL;
Elf32_Ehdr *hdr;
if(fd == -1) {
DL_ERR("Library '%s' not found", name);
return NULL;
}
/* We have to read the ELF header to figure out what to do with this image
*/
if (lseek(fd, 0, SEEK_SET) < 0) {
DL_ERR("lseek() failed!");
goto fail;
}
if ((cnt = read(fd, &__header[0], PAGE_SIZE)) < 0) {
DL_ERR("read() failed!");
goto fail;
}
/* Parse the ELF header and get the size of the memory footprint for
* the library */
req_base = get_lib_extents(name, &__header[0], &ext_sz);
if (req_base == (unsigned)-1)
goto fail;
TRACE("[ %5d - '%s' (%s) wants base=0x%08x sz=0x%08x ]\n", pid, name,
(req_base ? "prelinked" : "not pre-linked"), req_base, ext_sz);
/* Now configure the soinfo struct where we'll store all of our data
* for the ELF object. If the loading fails, we waste the entry, but
* same thing would happen if we failed during linking. Configuring the
* soinfo struct here is a lot more convenient.
*/
si = alloc_info(name);
if (si == NULL)
goto fail;
TRACE("[ load_library, after alloc_info, si->name is %s, and name is %s ]\n", si->name, name);
/* Carve out a chunk of memory where we will map in the individual
* segments */
si->base = req_base;
si->size = ext_sz;
si->flags = 0;
si->entry = 0;
si->dynamic = (unsigned *)-1;
if (alloc_mem_region(si) < 0)
goto fail;
TRACE("[ %5d allocated memory for %s @ %p (0x%08x) ]\n",
pid, name, (void *)si->base, (unsigned) ext_sz);
/* Now actually load the library's segments into right places in memory */
if (load_segments(fd, &__header[0], si) < 0) {
#if 0 // PKS .. don't need yet
if (si->ba_index >= 0) {
ba_free(&ba_nonprelink, si->ba_index);
si->ba_index = -1;
}
goto fail;
#endif
INFO("i am a fuckface and this failed\n");
goto fail;
}
/* this might not be right. Technically, we don't even need this info
* once we go through 'load_segments'. */
hdr = (Elf32_Ehdr *)si->base;
si->phdr = (Elf32_Phdr *)((unsigned char *)(si->base) + hdr->e_phoff);
si->phnum = hdr->e_phnum;
INFO("[ in load_library, hdr = %08x, base = %08x, phdr = %08x, phnum = %d, e_phoff = %04x ]\n", hdr, si->base, si->phdr, si->phnum, hdr->e_phoff);
/**/
close(fd);
return si;
fail:
if (si) free_info(si);
close(fd);
return NULL;
}
static soinfo *
load_library_buf(const char *name, void *buf, size_t len)
{
int cnt;
unsigned ext_sz;
unsigned req_base;
const char *bname;
soinfo *si = NULL;
Elf32_Ehdr *hdr;
memcpy(__header, buf, PAGE_SIZE);
/* Parse the ELF header and get the size of the memory footprint for
* the library */
req_base = get_lib_extents(name, &__header[0], &ext_sz);
if (req_base == (unsigned)-1)
goto fail;
TRACE("[ %5d - '%s' (%s) wants base=0x%08x sz=0x%08x ]\n", pid, name,
(req_base ? "prelinked" : "not pre-linked"), req_base, ext_sz);
/* Now configure the soinfo struct where we'll store all of our data
* for the ELF object. If the loading fails, we waste the entry, but
* same thing would happen if we failed during linking. Configuring the
* soinfo struct here is a lot more convenient.
*/
si = alloc_info(name);
if (si == NULL)
goto fail;
TRACE("[ load_library_buf, after alloc_info, si->name is %s, and name is %s ]\n", si->name, name);
/* Carve out a chunk of memory where we will map in the individual
* segments */
si->base = req_base;
si->size = ext_sz;
si->flags = 0;
si->entry = 0;
si->dynamic = (unsigned *)-1;
if (alloc_mem_region(si) < 0)
goto fail;
TRACE("[ %5d allocated memory for %s @ %p (0x%08x) ]\n",
pid, name, (void *)si->base, (unsigned) ext_sz);
/* Now actually load the library's segments into right places in memory */
if (load_segments_buf(&__header[0], si, buf, len) < 0) {
#if 0 // PKS .. don't need yet
if (si->ba_index >= 0) {
ba_free(&ba_nonprelink, si->ba_index);
si->ba_index = -1;
}
goto fail;
#endif
INFO("i am a fuckface and this failed\n");
goto fail;
}
/* this might not be right. Technically, we don't even need this info
* once we go through 'load_segments'. */
hdr = (Elf32_Ehdr *)si->base;
si->phdr = (Elf32_Phdr *)((unsigned char *)(si->base) + hdr->e_phoff);
si->phnum = hdr->e_phnum;
INFO("[ in load_library_buf, hdr = %08x, base = %08x, phdr = %08x, phnum = %d, e_phoff = %04x ]\n", hdr, si->base, si->phdr, si->phnum, hdr->e_phoff);
/**/
return si;
fail:
if (si) free_info(si);
return NULL;
}
static soinfo *
init_library(soinfo *si)
{
unsigned wr_offset = 0xffffffff;
/* At this point we know that whatever is loaded @ base is a valid ELF
* shared library whose segments are properly mapped in. */
TRACE("[ %5d init_library base=0x%08x sz=0x%08x name='%s') ]\n",
pid, si->base, si->size, si->name);
if (si->base < LIBBASE || si->base >= LIBLAST)
si->flags |= FLAG_PRELINKED;
if(link_image(si, wr_offset)) {
/* We failed to link. However, we can only restore libbase
** if no additional libraries have moved it since we updated it.
*/
munmap((void *)si->base, si->size);
return NULL;
}
return si;
}
soinfo *find_library(const char *name)
{
soinfo *si;
//const char *bname = strrchr(name, '/');
//bname = bname ? bname + 1 : name;
const char *bname = name;
for(si = solist; si != 0; si = si->next){
if(!strcmp(bname, si->name)) {
if(si->flags & FLAG_ERROR) {
DL_ERR("%5d '%s' failed to load previously", pid, bname);
return NULL;
}
if(si->flags & FLAG_LINKED) return si;
DL_ERR("OOPS: %5d recursive link to '%s'", pid, si->name);
return NULL;
}
}
TRACE("[ %5d '%s' has not been loaded yet. Locating...]\n", pid, name);
si = load_library(name);
if(si == NULL)
return NULL;
return init_library(si);
}
soinfo *find_library_buf(const char *name, void *buf, size_t size)
{
soinfo *si;
for(si = solist; si != 0; si = si->next) {
if(!strcmp(name, si->name)) {
if(si->flags & FLAG_ERROR) return NULL;
if(si->flags & FLAG_LINKED) return si;
return NULL;
}
}
TRACE("[ %5d '%s' has not been loaded yet. Loading...]\n", pid, name);
si = load_library_buf(name, buf, size);
if(si == NULL)
return NULL;
return init_library(si);
}
/* TODO:
* notify gdb of unload
* for non-prelinked libraries, find a way to decrement libbase
*/
static void call_destructors(soinfo *si);
unsigned unload_library(soinfo *si)
{
unsigned *d;
if (si->refcount == 1) {
TRACE("%5d unloading '%s'\n", pid, si->name);
call_destructors(si);
for(d = si->dynamic; *d; d += 2) {
if(d[0] == DT_NEEDED){
soinfo *lsi = (soinfo *)d[1];
d[1] = 0;
if (validate_soinfo(lsi)) {
TRACE("%5d %s needs to unload %s\n", pid,
si->name, lsi->name);
unload_library(lsi);
}
else
DL_ERR("%5d %s: could not unload dependent library",
pid, si->name);
}
}
munmap((char *)si->base, si->size);
#if 0 // PKS don't need yet
if (si->ba_index >= 0) {
PRINT("%5d releasing library '%s' address space at %08x "\
"through buddy allocator.\n",
pid, si->name, si->base);
ba_free(&ba_nonprelink, si->ba_index);
}
#endif
free_info(si);
si->refcount = 0; // PKS, use after free? ;P
}
else {
si->refcount--;
PRINT("%5d not unloading '%s', decrementing refcount to %d\n",
pid, si->name, si->refcount);
}
return si->refcount;
}
/* TODO: don't use unsigned for addrs below. It works, but is not
* ideal. They should probably be either uint32_t, Elf32_Addr, or unsigned
* long.
*/
static int reloc_library(soinfo *si, Elf32_Rel *rel, unsigned count)
{
Elf32_Sym *symtab = si->symtab;
const char *strtab = si->strtab;
Elf32_Sym *s;
unsigned base;
Elf32_Rel *start = rel;
unsigned idx;
for (idx = 0; idx < count; ++idx) {
unsigned type = ELF32_R_TYPE(rel->r_info);
unsigned sym = ELF32_R_SYM(rel->r_info);
unsigned reloc = (unsigned)(rel->r_offset + si->base);
unsigned sym_addr = 0;
char *sym_name = NULL;
DEBUG("%5d Processing '%s' relocation at index %d via reloc_library\n", pid,
si->name, idx);
if(sym != 0) {
sym_name = (char *)(strtab + symtab[sym].st_name);
s = _do_lookup(si, sym_name, &base);
if(s == NULL) {
/* We only allow an undefined symbol if this is a weak
reference.. */
s = &symtab[sym];
if (ELF32_ST_BIND(s->st_info) != STB_WEAK) {
DL_ERR("%5d cannot locate '%s'...\n", pid, sym_name);
return -1;
}
/* IHI0044C AAELF 4.5.1.1:
Libraries are not searched to resolve weak references.
It is not an error for a weak reference to remain
unsatisfied.
During linking, the value of an undefined weak reference is:
- Zero if the relocation type is absolute
- The address of the place if the relocation is pc-relative
- The address of nominial base address if the relocation
type is base-relative.
*/
switch (type) {
#if defined(ANDROID_ARM_LINKER)
case R_ARM_JUMP_SLOT:
case R_ARM_GLOB_DAT:
case R_ARM_ABS32:
case R_ARM_RELATIVE: /* Don't care. */
case R_ARM_NONE: /* Don't care. */
#elif defined(ANDROID_X86_LINKER)
case R_386_JUMP_SLOT:
case R_386_GLOB_DAT:
case R_386_32:
case R_386_RELATIVE: /* Dont' care. */
#endif /* ANDROID_*_LINKER */
/* sym_addr was initialized to be zero above or relocation
code below does not care about value of sym_addr.
No need to do anything. */
break;
#if defined(ANDROID_X86_LINKER)
case R_386_PC32:
sym_addr = reloc;
break;
#endif /* ANDROID_X86_LINKER */
#if defined(ANDROID_ARM_LINKER)
case R_ARM_COPY:
/* Fall through. Can't really copy if weak symbol is
not found in run-time. */
#endif /* ANDROID_ARM_LINKER */
default:
DL_ERR("%5d unknown weak reloc type %d @ %p (%d)\n",
pid, type, rel, (int) (rel - start));
return -1;
}
} else {
/* We got a definition. */
#if 0
if((base == 0) && (si->base != 0)){
/* linking from libraries to main image is bad */
DL_ERR("%5d cannot locate '%s'...",
pid, strtab + symtab[sym].st_name);
return -1;
}
#endif
sym_addr = (unsigned)(s->st_value + base);
}
} else {
s = NULL;
}
/* TODO: This is ugly. Split up the relocations by arch into
* different files.
*/
switch(type){
#if defined(ANDROID_ARM_LINKER)
case R_ARM_JUMP_SLOT:
MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO JMP_SLOT %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) = sym_addr;
break;
case R_ARM_GLOB_DAT:
MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO GLOB_DAT %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) = sym_addr;
break;
case R_ARM_ABS32:
MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO ABS %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) += sym_addr;
break;
case R_ARM_REL32:
MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO REL32 %08x <- %08x - %08x %s\n", pid,
reloc, sym_addr, rel->r_offset, sym_name);
*((unsigned*)reloc) += sym_addr - rel->r_offset;
break;
#elif defined(ANDROID_X86_LINKER)
case R_386_JUMP_SLOT:
// MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO JMP_SLOT %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) = sym_addr;
break;
case R_386_GLOB_DAT:
// MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO GLOB_DAT %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) = sym_addr;
break;
#endif /* ANDROID_*_LINKER */
#if defined(ANDROID_ARM_LINKER)
case R_ARM_RELATIVE:
#elif defined(ANDROID_X86_LINKER)
case R_386_RELATIVE:
#endif /* ANDROID_*_LINKER */
// MARK(rel->r_offset);
if(sym){
DL_ERR("%5d odd RELATIVE form...", pid);
return -1;
}
TRACE_TYPE(RELO, "%5d RELO RELATIVE %08x <- +%08x\n", pid,
reloc, si->base);
*((unsigned*)reloc) += si->base;
break;
#if defined(ANDROID_X86_LINKER)
case R_386_32:
// MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO R_386_32 %08x <- +%08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned *)reloc) += (unsigned)sym_addr;
break;
case R_386_PC32:
// MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO R_386_PC32 %08x <- "
"+%08x (%08x - %08x) %s\n", pid, reloc,
(sym_addr - reloc), sym_addr, reloc, sym_name);
*((unsigned *)reloc) += (unsigned)(sym_addr - reloc);
break;
#endif /* ANDROID_X86_LINKER */
#ifdef ANDROID_ARM_LINKER
case R_ARM_COPY:
MARK(rel->r_offset);
TRACE_TYPE(RELO, "%5d RELO %08x <- %d @ %08x %s\n", pid,
reloc, s->st_size, sym_addr, sym_name);
memcpy((void*)reloc, (void*)sym_addr, s->st_size);
break;
case R_ARM_NONE:
break;
#endif /* ANDROID_ARM_LINKER */
default:
DL_ERR("%5d unknown reloc type %d @ %p (%d)",
pid, type, rel, (int) (rel - start));
return -1;
}
rel++;
}
return 0;
}
#if defined(ANDROID_SH_LINKER)
static int reloc_library_a(soinfo *si, Elf32_Rela *rela, unsigned count)
{
Elf32_Sym *symtab = si->symtab;
const char *strtab = si->strtab;
Elf32_Sym *s;
unsigned base;
Elf32_Rela *start = rela;
unsigned idx;
for (idx = 0; idx < count; ++idx) {
unsigned type = ELF32_R_TYPE(rela->r_info);
unsigned sym = ELF32_R_SYM(rela->r_info);
unsigned reloc = (unsigned)(rela->r_offset + si->base);
unsigned sym_addr = 0;
char *sym_name = NULL;
DEBUG("%5d Processing '%s' relocation at index %d via reloc_library_a\n", pid,
si->name, idx);
if(sym != 0) {
sym_name = (char *)(strtab + symtab[sym].st_name);
s = _do_lookup(si, sym_name, &base);
if(s == 0) {
DL_ERR("%5d cannot locate '%s'...", pid, sym_name);
return -1;
}
#if 0
if((base == 0) && (si->base != 0)){
/* linking from libraries to main image is bad */
DL_ERR("%5d cannot locate '%s'...",
pid, strtab + symtab[sym].st_name);
return -1;
}
#endif
if ((s->st_shndx == SHN_UNDEF) && (s->st_value != 0)) {
DL_ERR("%5d In '%s', shndx=%d && value=0x%08x. We do not "
"handle this yet", pid, si->name, s->st_shndx,
s->st_value);
return -1;
}
sym_addr = (unsigned)(s->st_value + base);
COUNT_RELOC(RELOC_SYMBOL);
} else {
s = 0;
}
/* TODO: This is ugly. Split up the relocations by arch into
* different files.
*/
switch(type){
case R_SH_JUMP_SLOT:
COUNT_RELOC(RELOC_ABSOLUTE);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "%5d RELO JMP_SLOT %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) = sym_addr;
break;
case R_SH_GLOB_DAT:
COUNT_RELOC(RELOC_ABSOLUTE);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "%5d RELO GLOB_DAT %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) = sym_addr;
break;
case R_SH_DIR32:
COUNT_RELOC(RELOC_ABSOLUTE);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "%5d RELO DIR32 %08x <- %08x %s\n", pid,
reloc, sym_addr, sym_name);
*((unsigned*)reloc) += sym_addr;
break;
case R_SH_RELATIVE:
COUNT_RELOC(RELOC_RELATIVE);
MARK(rela->r_offset);
if(sym){
DL_ERR("%5d odd RELATIVE form...", pid);
return -1;
}
TRACE_TYPE(RELO, "%5d RELO RELATIVE %08x <- +%08x\n", pid,
reloc, si->base);
*((unsigned*)reloc) += si->base;
break;
default:
DL_ERR("%5d unknown reloc type %d @ %p (%d)",
pid, type, rela, (int) (rela - start));
return -1;
}
rela++;
}
return 0;
}
#endif /* ANDROID_SH_LINKER */
/* Please read the "Initialization and Termination functions" functions.
* of the linker design note in bionic/linker/README.TXT to understand
* what the following code is doing.
*
* The important things to remember are:
*
* DT_PREINIT_ARRAY must be called first for executables, and should
* not appear in shared libraries.
*
* DT_INIT should be called before DT_INIT_ARRAY if both are present
*
* DT_FINI should be called after DT_FINI_ARRAY if both are present
*
* DT_FINI_ARRAY must be parsed in reverse order.
*/
static void call_array(unsigned *ctor, int count, int reverse)
{
int n, inc = 1;
if (reverse) {
ctor += (count-1);
inc = -1;
}
for(n = count; n > 0; n--) {
TRACE("[ %5d Looking at %s *0x%08x == 0x%08x ]\n", pid,
reverse ? "dtor" : "ctor",
(unsigned)ctor, (unsigned)*ctor);
void (*func)() = (void (*)()) *ctor;
ctor += inc;
if(((int) func == 0) || ((int) func == -1)) continue;
TRACE("[ %5d Calling func @ 0x%08x ]\n", pid, (unsigned)func);
func();
}
}
static void call_constructors(soinfo *si)
{
TRACE("[ call_constructors ]\n");
if (si->flags & FLAG_EXE) {
TRACE("[ %5d Calling preinit_array @ 0x%08x [%d] for '%s' ]\n",
pid, (unsigned)si->preinit_array, si->preinit_array_count,
si->name);
call_array(si->preinit_array, si->preinit_array_count, 0);
TRACE("[ %5d Done calling preinit_array for '%s' ]\n", pid, si->name);
} else {
if (si->preinit_array) {
DL_ERR("%5d Shared library '%s' has a preinit_array table @ 0x%08x."
" This is INVALID.", pid, si->name,
(unsigned)si->preinit_array);
}
}
if (si->init_func) {
TRACE("[ %5d Calling init_func @ 0x%08x for '%s' ]\n", pid,
(unsigned)si->init_func, si->name);
si->init_func();
TRACE("[ %5d Done calling init_func for '%s' ]\n", pid, si->name);
}
if (si->init_array) {
TRACE("[ %5d Calling init_array @ 0x%08x [%d] for '%s' ]\n", pid,
(unsigned)si->init_array, si->init_array_count, si->name);
call_array(si->init_array, si->init_array_count, 0);
TRACE("[ %5d Done calling init_array for '%s' ]\n", pid, si->name);
}
}
static void call_destructors(soinfo *si)
{
if (si->fini_array) {
TRACE("[ %5d Calling fini_array @ 0x%08x [%d] for '%s' ]\n", pid,
(unsigned)si->fini_array, si->fini_array_count, si->name);
call_array(si->fini_array, si->fini_array_count, 1);
TRACE("[ %5d Done calling fini_array for '%s' ]\n", pid, si->name);
}
if (si->fini_func) {
TRACE("[ %5d Calling fini_func @ 0x%08x for '%s' ]\n", pid,
(unsigned)si->fini_func, si->name);
si->fini_func();
TRACE("[ %5d Done calling fini_func for '%s' ]\n", pid, si->name);
}
}
#ifndef DT_GNU_HASH
#define DT_GNU_HASH 0x6ffffef5
#endif
static int link_image(soinfo *si, unsigned wr_offset)
{
unsigned *d;
Elf32_Phdr *phdr = si->phdr;
int phnum = si->phnum;
INFO("[ %5d linking %s ]\n", pid, si->name);
DEBUG("[ %5d si->base = 0x%08x si->flags = 0x%08x ]\n", pid,
si->base, si->flags);
INFO("[ si->phnum = %d, si->phdr = 0x%08x\n", si->phnum, si->phdr);
si->flags |= FLAG_EXE; // PKS, just for now
if (si->flags & FLAG_EXE) {
/* Locate the needed program segments (DYNAMIC/ARM_EXIDX) for
* linkage info if this is the executable. If this was a
* dynamic lib, that would have been done at load time.
*
* TODO: It's unfortunate that small pieces of this are
* repeated from the load_library routine. Refactor this just
* slightly to reuse these bits.
*/
si->size = 0;
for(; phnum > 0; --phnum, ++phdr) {
INFO("[ at phdr %08x, we have p_type of %d, oh and si->base is %08x]\n", phdr, phdr->p_type, si->base);
#ifdef ANDROID_ARM_LINKER
if(phdr->p_type == PT_ARM_EXIDX) {
/* exidx entries (used for stack unwinding) are 8 bytes each.
*/
si->ARM_exidx = (unsigned *)phdr->p_vaddr;
si->ARM_exidx_count = phdr->p_memsz / 8;
}
#endif
if (phdr->p_type == PT_LOAD) {
/* For the executable, we use the si->size field only in
dl_unwind_find_exidx(), so the meaning of si->size
is not the size of the executable; it is the last
virtual address of the loadable part of the executable;
since si->base == 0 for an executable, we use the
range [0, si->size) to determine whether a PC value
falls within the executable section. Of course, if
a value is below phdr->p_vaddr, it's not in the
executable section, but a) we shouldn't be asking for
such a value anyway, and b) if we have to provide
an EXIDX for such a value, then the executable's
EXIDX is probably the better choice.
*/
DEBUG_DUMP_PHDR(phdr, "PT_LOAD", pid);
if (phdr->p_vaddr + phdr->p_memsz > si->size)
si->size = phdr->p_vaddr + phdr->p_memsz;
/* try to remember what range of addresses should be write
* protected */
if (!(phdr->p_flags & PF_W)) {
unsigned _end;
if (phdr->p_vaddr < si->wrprotect_start)
si->wrprotect_start = phdr->p_vaddr;
_end = (((phdr->p_vaddr + phdr->p_memsz + PAGE_SIZE - 1) &
(~PAGE_MASK)));
if (_end > si->wrprotect_end)
si->wrprotect_end = _end;
}
} else if (phdr->p_type == PT_DYNAMIC) {
if (si->dynamic != (unsigned *)-1 && si->dynamic != (unsigned *)(si->base + phdr->p_vaddr)) {
DL_ERR("%5d multiple PT_DYNAMIC segments found in '%s'. "
"Segment at 0x%08x, previously one found at 0x%08x",
pid, si->name, si->base + phdr->p_vaddr,
(unsigned)si->dynamic);
goto fail;
}
DEBUG_DUMP_PHDR(phdr, "PT_DYNAMIC", pid);
si->dynamic = (unsigned *) (si->base + phdr->p_vaddr);
}
}
}
if (si->dynamic == (unsigned *)-1) {
DL_ERR("%5d missing PT_DYNAMIC?!", pid);
goto fail;
}
DEBUG("[ %5d dynamic = %08x ]\n", pid, si->dynamic);
DEBUG("[ looping over dynamic header ]\n");
/* si->dynamic is an array of Elf32_Dyn structs that look like this:
*
* typedef struct dynamic{
* Elf32_Sword d_tag;
* union{
* Elf32_Sword d_val;
* Elf32_Addr d_ptr;
* } d_un;
* } Elf32_Dyn;
*
* It's easier to deal with them as a two-element array of (unsigned *)'s,
* where d[0] is d_tag and d[1] is d_val or d_ptr.
*
* -egypt
*/
/* extract useful information from dynamic section */
for(d = si->dynamic; *d; d++){
DEBUG("[ %5d d = %p, d[0] = 0x%08x d[1] = 0x%08x ]\n", pid, d, d[0], d[1]);
switch(*d++){
case DT_HASH:
si->nbucket = ((unsigned *) (si->base + *d))[0];
si->nchain = ((unsigned *) (si->base + *d))[1];
si->bucket = (unsigned *) (si->base + *d + 8);
si->chain = (unsigned *) (si->base + *d + 8 + si->nbucket * 4);
break;
case DT_STRTAB:
si->strtab = (const char *) (si->base + *d);
break;
case DT_SYMTAB:
si->symtab = (Elf32_Sym *) (si->base + *d);
break;
#if !defined(ANDROID_SH_LINKER)
case DT_PLTREL:
if(*d != DT_REL) {
DL_ERR("DT_RELA not supported");
goto fail;
}
break;
#endif
#ifdef ANDROID_SH_LINKER
case DT_JMPREL:
si->plt_rela = (Elf32_Rela*) (si->base + *d);
break;
case DT_PLTRELSZ:
si->plt_rela_count = *d / sizeof(Elf32_Rela);
break;
#else
case DT_JMPREL:
si->plt_rel = (Elf32_Rel*) (si->base + *d);
break;
case DT_PLTRELSZ:
si->plt_rel_count = *d / 8;
break;
#endif
case DT_REL:
si->rel = (Elf32_Rel*) (si->base + *d);
break;
case DT_RELSZ:
si->rel_count = *d / 8;
break;
#ifdef ANDROID_SH_LINKER
case DT_RELASZ:
si->rela_count = *d / sizeof(Elf32_Rela);
break;
#endif
case DT_PLTGOT:
/* Save this in case we decide to do lazy binding. We don't yet. */
si->plt_got = (unsigned *)(si->base + *d);
break;
case DT_DEBUG:
// Set the DT_DEBUG entry to the addres of _r_debug for GDB
// *d = (int) &_r_debug;
// PKS, we don't support this.
break;
#ifdef ANDROID_SH_LINKER
case DT_RELA:
si->rela = (Elf32_Rela *) (si->base + *d);
break;
#else
case DT_RELA:
DL_ERR("%5d DT_RELA not supported", pid);
goto fail;
#endif
case DT_INIT:
si->init_func = (void (*)(void))(si->base + *d);
DEBUG("%5d %s constructors (init func) found at %p\n",
pid, si->name, si->init_func);
break;
case DT_FINI:
si->fini_func = (void (*)(void))(si->base + *d);
DEBUG("%5d %s destructors (fini func) found at %p\n",
pid, si->name, si->fini_func);
break;
case DT_INIT_ARRAY:
si->init_array = (unsigned *)(si->base + *d);
DEBUG("%5d %s constructors (init_array) found at %p\n",
pid, si->name, si->init_array);
break;
case DT_INIT_ARRAYSZ:
si->init_array_count = ((unsigned)*d) / sizeof(Elf32_Addr);
break;
case DT_FINI_ARRAY:
si->fini_array = (unsigned *)(si->base + *d);
DEBUG("%5d %s destructors (fini_array) found at %p\n",
pid, si->name, si->fini_array);
break;
case DT_FINI_ARRAYSZ:
si->fini_array_count = ((unsigned)*d) / sizeof(Elf32_Addr);
break;
case DT_PREINIT_ARRAY:
si->preinit_array = (unsigned *)(si->base + *d);
DEBUG("%5d %s constructors (preinit_array) found at %p\n",
pid, si->name, si->preinit_array);
break;
case DT_PREINIT_ARRAYSZ:
si->preinit_array_count = ((unsigned)*d) / sizeof(Elf32_Addr);
break;
case DT_TEXTREL:
/* TODO: make use of this. */
/* this means that we might have to write into where the text
* segment was loaded during relocation... Do something with
* it.
*/
DEBUG("%5d Text segment should be writable during relocation.\n",
pid);
break;
case DT_GNU_HASH:
/// PKS .. implement properly ?
break;
// default:
// DEBUG("[ unhandled DT_ header. this will probably break parsing ]\n");
// exit(0);
// break;
}
}
DEBUG("%5d si->base = 0x%08x, si->strtab = %p, si->symtab = %p\n",
pid, si->base, si->strtab, si->symtab);
if((si->strtab == 0) || (si->symtab == 0)) {
DL_ERR("%5d missing essential tables.. strtab = %08x, symtab = %08x", pid, si->strtab, si->symtab);
goto fail;
}
#if 0 // PKS, don't support ldpreload cra
/* if this is the main executable, then load all of the preloads now */
if(si->flags & FLAG_EXE) {
int i;
memset(preloads, 0, sizeof(preloads));
for(i = 0; ldpreload_names[i] != NULL; i++) {
soinfo *lsi = find_library(ldpreload_names[i]);
if(lsi == 0) {
strlcpy(tmp_err_buf, linker_get_error(), sizeof(tmp_err_buf));
DL_ERR("%5d could not load needed library '%s' for '%s' (%s)",
pid, ldpreload_names[i], si->name, tmp_err_buf);
goto fail;
}
lsi->refcount++;
preloads[i] = lsi;
}
}
#endif
for(d = si->dynamic; *d; d += 2) {
if(d[0] == DT_NEEDED){
DEBUG("%5d %s needs %s\n", pid, si->name, si->strtab + d[1]);
soinfo *lsi = find_library(si->strtab + d[1]);
if(lsi == 0) {
strcpy(tmp_err_buf, linker_get_error()); // PKS , sizeof(tmp_err_buf));
DL_ERR("%5d could not load needed library '%s' for '%s' (%s)",
pid, si->strtab + d[1], si->name, tmp_err_buf);
goto fail;
}
/* Save the soinfo of the loaded DT_NEEDED library in the payload
of the DT_NEEDED entry itself, so that we can retrieve the
soinfo directly later from the dynamic segment. This is a hack,
but it allows us to map from DT_NEEDED to soinfo efficiently
later on when we resolve relocations, trying to look up a symgol
with dlsym().
*/
d[1] = (unsigned)lsi;
lsi->refcount++;
}
}
if(si->plt_rel) {
DEBUG("[ %5d relocating %s plt ]\n", pid, si->name );
if(reloc_library(si, si->plt_rel, si->plt_rel_count))
goto fail;
}
if(si->rel) {
DEBUG("[ %5d relocating %s ]\n", pid, si->name );
if(reloc_library(si, si->rel, si->rel_count))
goto fail;
}
#ifdef ANDROID_SH_LINKER
if(si->plt_rela) {
DEBUG("[ %5d relocating %s plt ]\n", pid, si->name );
if(reloc_library_a(si, si->plt_rela, si->plt_rela_count))
goto fail;
}
if(si->rela) {
DEBUG("[ %5d relocating %s ]\n", pid, si->name );
if(reloc_library_a(si, si->rela, si->rela_count))
goto fail;
}
#endif /* ANDROID_SH_LINKER */
si->flags |= FLAG_LINKED;
DEBUG("[ %5d finished linking %s ]\n", pid, si->name);
#if 0
/* This is the way that the old dynamic linker did protection of
* non-writable areas. It would scan section headers and find where
* .text ended (rather where .data/.bss began) and assume that this is
* the upper range of the non-writable area. This is too coarse,
* and is kept here for reference until we fully move away from single
* segment elf objects. See the code in get_wr_offset (also #if'd 0)
* that made this possible.
*/
if(wr_offset < 0xffffffff){
mprotect((void*) si->base, wr_offset, PROT_READ | PROT_EXEC);
}
#else
/* TODO: Verify that this does the right thing in all cases, as it
* presently probably does not. It is possible that an ELF image will
* come with multiple read-only segments. What we ought to do is scan
* the program headers again and mprotect all the read-only segments.
* To prevent re-scanning the program header, we would have to build a
* list of loadable segments in si, and then scan that instead. */
if (si->wrprotect_start != 0xffffffff && si->wrprotect_end != 0) {
mprotect((void *)si->wrprotect_start,
si->wrprotect_end - si->wrprotect_start,
PROT_READ | PROT_EXEC);
}
#endif
/* If this is a SET?ID program, dup /dev/null to opened stdin,
stdout and stderr to close a security hole described in:
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-02:23.stdio.asc
*/
#if 0 // PKS, no.
if (getuid() != geteuid() || getgid() != getegid())
nullify_closed_stdio ();
#endif
call_constructors(si);
return 0;
fail:
DL_ERR("failed to link %s\n", si->name);
si->flags |= FLAG_ERROR;
return -1;
}