pub unsafe fn read_str(name: &[u8]) -> Result<&'static [u8]>Expand description
Uses the null-terminated string name as key to the MALLCTL NAMESPACE and
reads its value.
ยงSafety
This function is unsafe because if the key does not return a pointer to a null-terminated string the behavior is undefined.
For example, a key for a u64 value can be used to read a pointer on 64-bit
platform, where this pointer will point to the address denoted by the u64s
representation. Also, a key to a *mut extent_hooks_t will return a pointer
that will not point to a null-terminated string.
This function needs to compute the length of the string by looking for the
null-terminator: \0. This requires reading the memory behind the pointer.
If the pointer is invalid (e.g. because it was converted from a u64 that
does not represent a valid address), reading the string to look for \0
will dereference a non-dereferenceable pointer, which is undefined behavior.
If the pointer is valid but it does not point to a null-terminated string,
looking for \0 will read garbage and might end up reading out-of-bounds,
which is undefined behavior.