int NaClVmmapChangeProt(struct NaClVmmap *self,
uintptr_t page_num,
size_t npages,
int prot) {
size_t i;
size_t nvalid;
uintptr_t new_region_end_page = page_num + npages;
/*
* NaClVmmapCheckExistingMapping should be always called before
* NaClVmmapChangeProt proceeds to ensure that valid mapping exists
* as modifications cannot be rolled back.
*/
if (!NaClVmmapCheckExistingMapping(self, page_num, npages, prot)) {
return 0;
}
NaClLog(2,
("NaClVmmapChangeProt(0x%08"NACL_PRIxPTR", 0x%"NACL_PRIxPTR
", 0x%"NACL_PRIxS", 0x%x)\n"),
(uintptr_t) self, page_num, npages, prot);
NaClVmmapMakeSorted(self);
/*
* This loop & interval boundary tests closely follow those in
* NaClVmmapUpdate. When updating those, do not forget to update them
* at both places where appropriate.
* TODO(phosek): use better data structure which will support intervals
*/
for (i = 0, nvalid = self->nvalid; i < nvalid && npages > 0; i++) {
struct NaClVmmapEntry *ent = self->vmentry[i];
uintptr_t ent_end_page = ent->page_num + ent->npages;
nacl_off64_t additional_offset =
(new_region_end_page - ent->page_num) << NACL_PAGESHIFT;
if (ent->page_num < page_num && new_region_end_page < ent_end_page) {
/* Split existing mapping into two parts */
NaClVmmapAdd(self,
new_region_end_page,
ent_end_page - new_region_end_page,
ent->prot,
ent->flags,
ent->desc,
ent->offset + additional_offset,
ent->file_size);
ent->npages = page_num - ent->page_num;
/* Add the new mapping into the middle. */
NaClVmmapAdd(self,
page_num,
npages,
prot,
ent->flags,
ent->desc,
ent->offset + (page_num - ent->page_num),
ent->file_size);
break;
} else if (ent->page_num < page_num && page_num < ent_end_page) {
/* New mapping overlaps end of existing mapping. */
ent->npages = page_num - ent->page_num;
/* Add the overlapping part of the mapping. */
NaClVmmapAdd(self,
page_num,
ent_end_page - page_num,
prot,
ent->flags,
ent->desc,
ent->offset + (page_num - ent->page_num),
ent->file_size);
/* The remaining part (if any) will be added in other iteration. */
page_num = ent_end_page;
npages = new_region_end_page - ent_end_page;
} else if (ent->page_num < new_region_end_page &&
new_region_end_page < ent_end_page) {
/* New mapping overlaps start of existing mapping, split it. */
NaClVmmapAdd(self,
page_num,
npages,
prot,
ent->flags,
ent->desc,
ent->offset,
ent->file_size);
ent->page_num = new_region_end_page;
ent->npages = ent_end_page - new_region_end_page;
ent->offset += additional_offset;
break;
} else if (page_num <= ent->page_num &&
ent_end_page <= new_region_end_page) {
/* New mapping covers all of the existing mapping. */
page_num = ent_end_page;
npages = new_region_end_page - ent_end_page;
ent->prot = prot;
} else {
/* No overlap */
assert(new_region_end_page <= ent->page_num || ent_end_page <= page_num);
}
}
return 1;
}
/*
* Update the virtual memory map. Deletion is handled by a remove
* flag, since a NULL nmop just means that the memory is backed by the
* system paging file.
*/
void NaClVmmapUpdate(struct NaClVmmap *self,
uintptr_t page_num,
size_t npages,
int prot,
struct NaClMemObj *nmop,
int remove) {
/* update existing entries or create new entry as needed */
size_t i;
uintptr_t new_region_end_page = page_num + npages;
NaClLog(2,
("NaClVmmapUpdate(0x%08"NACL_PRIxPTR", "
"0x%"NACL_PRIxPTR", 0x%"NACL_PRIxS", "
"0x%x, 0x%08"NACL_PRIxPTR", %d)\n"),
(uintptr_t) self, page_num, npages, prot, (uintptr_t) nmop,
remove);
NaClVmmapMakeSorted(self);
CHECK(npages > 0);
for (i = 0; i < self->nvalid; i++) {
struct NaClVmmapEntry *ent = self->vmentry[i];
uintptr_t ent_end_page = ent->page_num + ent->npages;
nacl_off64_t additional_offset =
(new_region_end_page - ent->page_num) << NACL_PAGESHIFT;
if (ent->page_num < page_num && new_region_end_page < ent_end_page) {
/*
* Split existing mapping into two parts, with new mapping in
* the middle.
*/
if (!NaClVmmapAdd(self,
new_region_end_page,
ent_end_page - new_region_end_page,
ent->prot,
NaClMemObjSplit(ent->nmop, additional_offset))) {
NaClLog(LOG_FATAL, "NaClVmmapUpdate: could not split entry\n");
}
ent->npages = page_num - ent->page_num;
break;
} else if (ent->page_num < page_num && page_num < ent_end_page) {
/* New mapping overlaps end of existing mapping. */
ent->npages = page_num - ent->page_num;
} else if (ent->page_num < new_region_end_page &&
new_region_end_page < ent_end_page) {
/* New mapping overlaps start of existing mapping. */
NaClMemObjIncOffset(ent->nmop, additional_offset);
ent->page_num = new_region_end_page;
ent->npages = ent_end_page - new_region_end_page;
break;
} else if (page_num <= ent->page_num &&
ent_end_page <= new_region_end_page) {
/* New mapping covers all of the existing mapping. */
ent->removed = 1;
} else {
/* No overlap */
assert(new_region_end_page <= ent->page_num || ent_end_page <= page_num);
}
}
if (!remove) {
if (!NaClVmmapAdd(self, page_num, npages, prot, nmop)) {
NaClLog(LOG_FATAL, "NaClVmmapUpdate: could not add entry\n");
}
}
NaClVmmapRemoveMarked(self);
}
/*
* Update the virtual memory map. Deletion is handled by a remove
* flag, since a NULL desc just means that the memory is backed by the
* system paging file.
*/
static void NaClVmmapUpdate(struct NaClVmmap *self,
uintptr_t page_num,
size_t npages,
int prot,
int flags,
int remove,
struct NaClDesc *desc,
nacl_off64_t offset,
nacl_off64_t file_size) {
/* update existing entries or create new entry as needed */
size_t i;
uintptr_t new_region_end_page = page_num + npages;
NaClLog(2,
("NaClVmmapUpdate(0x%08"NACL_PRIxPTR", 0x%"NACL_PRIxPTR", "
"0x%"NACL_PRIxS", 0x%x, 0x%x, %d, 0x%"NACL_PRIxPTR", "
"0x%"NACL_PRIx64")\n"),
(uintptr_t) self, page_num, npages, prot, flags,
remove, (uintptr_t) desc, offset);
NaClVmmapMakeSorted(self);
CHECK(npages > 0);
for (i = 0; i < self->nvalid; i++) {
struct NaClVmmapEntry *ent = self->vmentry[i];
uintptr_t ent_end_page = ent->page_num + ent->npages;
nacl_off64_t additional_offset =
(new_region_end_page - ent->page_num) << NACL_PAGESHIFT;
if (ent->page_num < page_num && new_region_end_page < ent_end_page) {
/*
* Split existing mapping into two parts, with new mapping in
* the middle.
*/
NaClVmmapAdd(self,
new_region_end_page,
ent_end_page - new_region_end_page,
ent->prot,
ent->flags,
ent->desc,
ent->offset + additional_offset,
ent->file_size);
ent->npages = page_num - ent->page_num;
break;
} else if (ent->page_num < page_num && page_num < ent_end_page) {
/* New mapping overlaps end of existing mapping. */
ent->npages = page_num - ent->page_num;
} else if (ent->page_num < new_region_end_page &&
new_region_end_page < ent_end_page) {
/* New mapping overlaps start of existing mapping. */
ent->page_num = new_region_end_page;
ent->npages = ent_end_page - new_region_end_page;
ent->offset += additional_offset;
break;
} else if (page_num <= ent->page_num &&
ent_end_page <= new_region_end_page) {
/* New mapping covers all of the existing mapping. */
ent->removed = 1;
} else {
/* No overlap */
assert(new_region_end_page <= ent->page_num || ent_end_page <= page_num);
}
}
if (!remove) {
NaClVmmapAdd(self, page_num, npages, prot, flags, desc, offset, file_size);
}
NaClVmmapRemoveMarked(self);
}