diff options
Diffstat (limited to 'src/fundamental/memory-util-fundamental.h')
| -rw-r--r-- | src/fundamental/memory-util-fundamental.h | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/src/fundamental/memory-util-fundamental.h b/src/fundamental/memory-util-fundamental.h index 67621fdb42..78e2dbec59 100644 --- a/src/fundamental/memory-util-fundamental.h +++ b/src/fundamental/memory-util-fundamental.h @@ -29,6 +29,8 @@ static inline void *explicit_bzero_safe(void *p, size_t l) { #endif struct VarEraser { + /* NB: This is a pointer to memory to erase in case of CLEANUP_ERASE(). Pointer to pointer to memory + * to erase in case of CLEANUP_ERASE_PTR() */ void *p; size_t size; }; @@ -38,5 +40,27 @@ static inline void erase_var(struct VarEraser *e) { } /* Mark var to be erased when leaving scope. */ -#define CLEANUP_ERASE(var) \ - _cleanup_(erase_var) _unused_ struct VarEraser CONCATENATE(_eraser_, UNIQ) = { .p = &var, .size = sizeof(var) } +#define CLEANUP_ERASE(var) \ + _cleanup_(erase_var) _unused_ struct VarEraser CONCATENATE(_eraser_, UNIQ) = { \ + .p = &(var), \ + .size = sizeof(var), \ + } + +static inline void erase_varp(struct VarEraser *e) { + + /* Very similar to erase_var(), but assumes `p` is a pointer to a pointer whose memory shall be destructed. */ + if (!e->p) + return; + + explicit_bzero_safe(*(void**) e->p, e->size); +} + +/* Mark pointer so that memory pointed to is erased when leaving scope. Note: this takes a pointer to the + * specified pointer, instead of just a copy of it. This is to allow callers to invalidate the pointer after + * use, if they like, disabling our automatic erasure (for example because they succeeded with whatever they + * wanted to do and now intend to return the allocated buffer to their caller without it being erased). */ +#define CLEANUP_ERASE_PTR(ptr, sz) \ + _cleanup_(erase_varp) _unused_ struct VarEraser CONCATENATE(_eraser_, UNIQ) = { \ + .p = (ptr), \ + .size = (sz), \ + } |