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/*
* OS and machine specific utility functions
* (C) 2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/os_utils.h>
#include <botan/exceptn.h>
#include <botan/mem_ops.h>
//TODO: defined(BOTAN_TARGET_OS_TYPE_IS_POSIX)
#if defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <unistd.h>
#endif
namespace Botan {
namespace OS {
size_t get_memory_locking_limit()
{
#if defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
/*
* Linux defaults to only 64 KiB of mlockable memory per process
* (too small) but BSDs offer a small fraction of total RAM (more
* than we need). Bound the total mlock size to 512 KiB which is
* enough to run the entire test suite without spilling to non-mlock
* memory (and thus presumably also enough for many useful
* programs), but small enough that we should not cause problems
* even if many processes are mlocking on the same machine.
*/
size_t mlock_requested = BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB;
/*
* Allow override via env variable
*/
if(const char* env = ::getenv("BOTAN_MLOCK_POOL_SIZE"))
{
try
{
const size_t user_req = std::stoul(env, nullptr);
mlock_requested = std::min(user_req, mlock_requested);
}
catch(std::exception&) { /* ignore it */ }
}
if(mlock_requested > 0)
{
struct ::rlimit limits;
::getrlimit(RLIMIT_MEMLOCK, &limits);
if(limits.rlim_cur < limits.rlim_max)
{
limits.rlim_cur = limits.rlim_max;
::setrlimit(RLIMIT_MEMLOCK, &limits);
::getrlimit(RLIMIT_MEMLOCK, &limits);
}
return std::min<size_t>(limits.rlim_cur, mlock_requested * 1024);
}
#endif
return 0;
}
void* allocate_locked_pages(size_t length)
{
#if defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
#if !defined(MAP_NOCORE)
#define MAP_NOCORE 0
#endif
#if !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON
#endif
void* ptr = ::mmap(nullptr,
length,
PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_SHARED | MAP_NOCORE,
/*fd*/-1,
/*offset*/0);
if(ptr == MAP_FAILED)
{
return nullptr;
}
#if defined(MADV_DONTDUMP)
::madvise(ptr, length, MADV_DONTDUMP);
#endif
if(::mlock(ptr, length) != 0)
{
::munmap(ptr, length);
return nullptr; // failed to lock
}
::memset(ptr, 0, length);
return ptr;
#else
return nullptr; /* not implemented */
#endif
}
void free_locked_pages(void* ptr, size_t length)
{
if(ptr == nullptr || length == 0)
return;
#if defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
zero_mem(ptr, length);
::munlock(ptr, length);
::munmap(ptr, length);
#else
// Invalid argument because no way this pointer was allocated by us
throw Invalid_Argument("Invalid ptr to free_locked_pages");
#endif
}
}
}
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