void *RemapPage(void * va){
kern_return_t kr;
mach_vm_address_t target_addr=0;
mach_vm_address_t source_addr;
vm_prot_t prot_cur = VM_PROT_READ | VM_PROT_WRITE;
vm_prot_t prot_max = VM_PROT_READ | VM_PROT_WRITE;
source_addr = (mach_vm_address_t) va;
kr = mach_vm_remap (mach_task_self(),
&target_addr,
PageSize,
0,
TRUE,
mach_task_self(),
source_addr,
FALSE,
&prot_cur,
&prot_max,
VM_INHERIT_SHARE);
if (kr != KERN_SUCCESS) {
printf(" mremap error: %d \n", kr);
printf(" no of pages used %d %d %d\n", AddressSpaceUsage1, AddressSpaceUsage2, AddressSpaceUsage2+AddressSpaceUsage1);
abort();
}
va = (void *) target_addr;
return va;
#ifdef FILESTATISTIC
logusage();
#endif
#ifdef STATISTIC
AddressSpaceUsage2++;
#endif
}
static int get_foreign_image_export(mach_port_t task, uint64_t hdr_addr,
void **linkedit_p, size_t *linkedit_size_p,
void **export_p, size_t *export_size_p,
cpu_type_t *cputype_p, char **error) {
mach_vm_offset_t hdr_buf = 0;
mach_vm_size_t hdr_buf_size;
int ret;
vm_prot_t cur, max;
hdr_buf_size = PAGE_SIZE;
kern_return_t kr = mach_vm_remap(mach_task_self(), &hdr_buf, hdr_buf_size, 0,
VM_FLAGS_ANYWHERE, task, hdr_addr,
/*copy*/ true, &cur, &max, VM_INHERIT_NONE);
if (kr) {
asprintf(error, "mach_vm_remap(libdyld header): kr=%d", kr);
return SUBSTITUTE_ERR_MISC;
}
struct mach_header *mh = (void *) hdr_buf;
if (mh->magic != MH_MAGIC && mh->magic != MH_MAGIC_64) {
asprintf(error, "bad magic in libdyld mach_header");
ret = SUBSTITUTE_ERR_MISC;
goto fail;
}
*cputype_p = mh->cputype;
size_t mh_size = mh->magic == MH_MAGIC_64 ? sizeof(struct mach_header_64)
: sizeof(struct mach_header);
if (mh->sizeofcmds < mh_size || mh->sizeofcmds > 128*1024)
goto badmach;
size_t total_size = mh_size + mh->sizeofcmds;
if (total_size > hdr_buf_size) {
vm_deallocate(mach_task_self(), (vm_offset_t) hdr_buf,
(vm_size_t) hdr_buf_size);
hdr_buf_size = total_size;
hdr_buf = 0;
kr = mach_vm_remap(mach_task_self(), &hdr_buf, hdr_buf_size, 0,
VM_FLAGS_ANYWHERE, task, hdr_addr, /*copy*/ true,
&cur, &max, VM_INHERIT_NONE);
if (kr) {
asprintf(error, "mach_vm_remap(libdyld header) #2: kr=%d", kr);
ret = SUBSTITUTE_ERR_MISC;
goto fail;
}
mh = (void *) hdr_buf;
}
struct load_command *lc = (void *) mh + mh_size;
uint32_t export_off = 0, export_size = 0;
uint64_t slide = 0;
for (uint32_t i = 0; i < mh->ncmds; i++, lc = (void *) lc + lc->cmdsize) {
size_t remaining = total_size - ((void *) lc - (void *) mh);
if (remaining < sizeof(*lc) || remaining < lc->cmdsize)
goto badmach;
if (lc->cmd == LC_DYLD_INFO || lc->cmd == LC_DYLD_INFO_ONLY) {
struct dyld_info_command *dc = (void *) lc;
if (lc->cmdsize < sizeof(*dc))
goto badmach;
export_off = dc->export_off;
export_size = dc->export_size;
} else if (lc->cmd == LC_SEGMENT) {
struct segment_command *sc = (void *) lc;
if (lc->cmdsize < sizeof(*sc))
goto badmach;
if (sc->fileoff == 0)
slide = hdr_addr - sc->vmaddr;
} else if (lc->cmd == LC_SEGMENT_64) {
struct segment_command_64 *sc = (void *) lc;
if (lc->cmdsize < sizeof(*sc))
goto badmach;
if (sc->fileoff == 0)
slide = hdr_addr - sc->vmaddr;
}
}
if (export_off == 0) {
asprintf(error, "no LC_DYLD_INFO in libdyld header");
ret = SUBSTITUTE_ERR_MISC;
goto fail;
}
lc = (void *) mh + mh_size;
uint64_t export_segoff, vmaddr, fileoff, filesize;
for (uint32_t i = 0; i < mh->ncmds; i++, lc = (void *) lc + lc->cmdsize) {
if (lc->cmd == LC_SEGMENT) {
struct segment_command *sc = (void *) lc;
vmaddr = sc->vmaddr;
fileoff = sc->fileoff;
filesize = sc->filesize;
} else if (lc->cmd == LC_SEGMENT_64) {
struct segment_command_64 *sc = (void *) lc;
vmaddr = sc->vmaddr;
fileoff = sc->fileoff;
filesize = sc->filesize;
} else {
continue;
}
export_segoff = (uint64_t) export_off - fileoff;
if (export_segoff < filesize) {
if (export_size > filesize - export_segoff)
goto badmach;
break;
}
}
uint64_t linkedit_addr = vmaddr + slide;
mach_vm_address_t linkedit_buf = 0;
kr = mach_vm_remap(mach_task_self(), &linkedit_buf, filesize, 0,
VM_FLAGS_ANYWHERE, task, linkedit_addr, /*copy*/ true,
&cur, &max, VM_INHERIT_NONE);
if (kr) {
asprintf(error, "mach_vm_remap(libdyld linkedit): kr=%d", kr);
ret = SUBSTITUTE_ERR_MISC;
goto fail;
}
*linkedit_p = (void *) linkedit_buf;
*linkedit_size_p = (size_t) filesize;
*export_p = (void *) linkedit_buf + export_segoff;
*export_size_p = export_size;
ret = SUBSTITUTE_OK;
goto fail;
badmach:
asprintf(error, "bad Mach-O data in libdyld header");
ret = SUBSTITUTE_ERR_MISC;
goto fail;
fail:
vm_deallocate(mach_task_self(), (vm_offset_t) hdr_buf,
(vm_size_t) hdr_buf_size);
return ret;
}
