vmutils 
cross platform virtual memory utilities library.
small example
// address can be unsinged integer or pointer
const auto region = vmu::query(address);
if(region && region.protection().accessible()) {
const auto new_flags = vmu::access::read_write_exec;
vmu::protection_guard guard(address, new_flags);
// do something
} // protection will be restored on scope exitquick reference
basic_region<Address>
Provides information about a memory region. Can be obtained using query or query_region.
| function | return type | explanation |
|---|---|---|
| begin | Address | beginning of region |
| end | Address | one past the end of region |
| size | uint big enough to store Address | size of region |
| protection | protection_t | the protection of page |
| guarded | bool | whether the region is guarded |
| shared | bool | whether the region is shared |
| operator bool | bool | whether the region is used |
protection_t
Wrapper class around protection flags.
| function | return type |
|---|---|
| accessible | bool |
| readable | bool |
| writable | bool |
| executable | bool |
| native | native_protection_t |
| to_flags | access |
access enumeration
- read
- write
- exec
- read_write
- read_exec
- write_exec
- read_write_exec
region query functions
Arguments in [] are not required - overloaded functions are present.
basic_region<RegionAddress> query([native_handle_t], Address, [std::error_code&])
Returns information about a region that the given address is in.
std::vector<basic_region<RegionAddress>> query_range([native_handle_t], Address, Address, [std::error_code&])
Returns information about regions that the given range of addresses are in.
The default for RegionAddress is std::uintptr_t or if the first function argument is of type
native_handle_t - std::uint64_t.
region protection
protection_guard
RAII based memory region protection and query class that protects a region of memory and restores it upon destruction.
If adopt_protection_t tag type is given constructor performs no actions and destructor sets the given protection instead.
In critical code it is recommended to manually call restore or define VMU_HANDLE_PG_DESTRUCTOR_FAILURE
macro that will handle errors in destructor, because by default on error memory regions is left unrestored.
constructor overloads:
protection_guard(Address, protection_t)protection_guard(Address, Address, protection_t)protection_guard(Range, protection_t)protection_guard(Address, protection_t, adopt_protection_t)protection_guard(Address, Address, protection_t, adopt_protection_t)protection_guard(Range, protection_t, adopt_protection_t)
| function | explanation |
|---|---|
| restore([std::error_code&]) | restores protection to its original state |
| release | "releases" protection so it does not get restored on object destruction |
void protect(Address, protection_t, [std::error_code&])
Changes protection of a single page that the address is in.
void protect(Address, Address, protection_t, [std::error_code&])
Changes protections of pages that range of addresses are in.
Address types
In library addresses are 32bit or 64bit unsigned integers or pointers. Conversions are applied automatically. By default every address that can cause an overflow / underflow is checked and an std::overflow_error is thrown if the target address type cannot represent the source address type.
An example of this would be if you called vmu::query<std::uint32_t>(std::numeric_limits<std::uint32_t>::max() * 2)
it's pretty obvious that this regions end will definetly overflow the requested 32 bit integer.