diff options
Diffstat (limited to 'src/lib/malloc/map_anon.h')
| -rw-r--r-- | src/lib/malloc/map_anon.h | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/src/lib/malloc/map_anon.h b/src/lib/malloc/map_anon.h index 395145bd71..6c02cd6c16 100644 --- a/src/lib/malloc/map_anon.h +++ b/src/lib/malloc/map_anon.h @@ -31,11 +31,41 @@ */ #define ANONMAP_NOINHERIT (1u<<1) -void *tor_mmap_anonymous(size_t sz, unsigned flags); -void tor_munmap_anonymous(void *mapping, size_t sz); +typedef enum { + /** Possible value for inherit_result_out: the memory will be kept + * by any child process. */ + INHERIT_RES_KEEP=0, + /** Possible value for inherit_result_out: the memory will be dropped in the + * child process. Attempting to access it will likely cause a segfault. */ + INHERIT_RES_DROP, + /** Possible value for inherit_result_out: the memory will be cleared in + * the child process. */ + INHERIT_RES_ZERO +} inherit_res_t; -#ifdef TOR_UNIT_TESTS -unsigned get_last_anon_map_noinherit(void); +/* Here we define the NOINHERIT_CAN_FAIL macro if and only if + * it's possible that ANONMAP_NOINHERIT might yield inheritable memory. + */ +#ifdef _WIN32 +/* Windows can't fork, so NOINHERIT is never needed. */ +#elif defined(HAVE_MINHERIT) +/* minherit() will always have a working MAP_INHERIT_NONE or MAP_INHERIT_ZERO. + * NOINHERIT should always work. + */ +#elif defined(HAVE_MADVISE) +/* madvise() sometimes has neither MADV_DONTFORK and MADV_WIPEONFORK. + * We need to be ready for the possibility it failed. + * + * (Linux added DONTFORK in 2.6.16 and WIPEONFORK in 4.14. If we someday + * require 2.6.16 or later, we can assume that DONTFORK will work.) + */ +#define NOINHERIT_CAN_FAIL +#else +#define NOINHERIT_CAN_FAIL #endif +void *tor_mmap_anonymous(size_t sz, unsigned flags, + inherit_res_t *inherit_result_out); +void tor_munmap_anonymous(void *mapping, size_t sz); + #endif /* !defined(TOR_MAP_ANON_H) */ |