diff options
| -rw-r--r-- | doc/relnotes/1_11_14.rst | 9 | ||||
| -rw-r--r-- | src/lib/alloc/locking_allocator/locking_allocator.cpp | 36 |
2 files changed, 36 insertions, 9 deletions
diff --git a/doc/relnotes/1_11_14.rst b/doc/relnotes/1_11_14.rst index 600f6dae1..f3a2527ad 100644 --- a/doc/relnotes/1_11_14.rst +++ b/doc/relnotes/1_11_14.rst @@ -7,3 +7,12 @@ Version 1.11.14, Not Yet Released finalized is not yet enabled by the default policy, and the ciphersuite numbers used are in the experimental range and may conflict with other uses. + +* The memory allocator available on Unix systems which uses mmap and + mlock to lock a pool of memory now checks an environment variable + BOTAN_MLOCK_POOL_SIZE. If this is set to a smaller value then the + library would originally have allocated the user specified size is + used. You can also set it to zero to disable the pool entirely. + Previously the allocator would consume all available mlocked memory, + this allows botan to coexist with an application which wants to + mlock memory of its own. diff --git a/src/lib/alloc/locking_allocator/locking_allocator.cpp b/src/lib/alloc/locking_allocator/locking_allocator.cpp index 643868c76..4a3dd3c4c 100644 --- a/src/lib/alloc/locking_allocator/locking_allocator.cpp +++ b/src/lib/alloc/locking_allocator/locking_allocator.cpp @@ -23,6 +23,21 @@ namespace { */ const size_t ALIGNMENT_MULTIPLE = 2; +size_t reset_mlock_limit(size_t max_req) + { + 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, max_req); + } + size_t mlock_limit() { /* @@ -34,19 +49,22 @@ size_t mlock_limit() * programs), but small enough that we should not cause problems * even if many processes are mlocking on the same machine. */ - const size_t MLOCK_UPPER_BOUND = 512*1024; - - struct rlimit limits; - ::getrlimit(RLIMIT_MEMLOCK, &limits); + size_t mlock_requested = 512; - if(limits.rlim_cur < limits.rlim_max) + /* + * Allow override via env variable + */ + if(const char* env = ::getenv("BOTAN_MLOCK_POOL_SIZE")) { - limits.rlim_cur = limits.rlim_max; - ::setrlimit(RLIMIT_MEMLOCK, &limits); - ::getrlimit(RLIMIT_MEMLOCK, &limits); + try + { + const size_t user_req = std::stoul(env, nullptr); + mlock_requested = std::min(user_req, mlock_requested); + } + catch(std::exception&) { /* ignore it */ } } - return std::min<size_t>(limits.rlim_cur, MLOCK_UPPER_BOUND); + return reset_mlock_limit(mlock_requested*1024); } bool ptr_in_pool(const void* pool_ptr, size_t poolsize, |