On Wed, 2010-06-16 at 20:25 -0400, Jacob Thompson wrote: > On Wed, 16 Jun 2010, Richard Matthew McCutchen wrote: > > So evidently the kernel prevents executables from being overwritten > > while in use, but there is no analogous feature for shared libraries. [...]
> POSIX might have something to say about this. POSIX documents the ETXTBSY behavior for executables as optional and doesn't mention ETXTBSY for shared libraries nor MAP_DENYWRITE at all. My understanding is that implementations are generally allowed to have additional error cases within reason, so I don't see anything in POSIX that would favor implementing ETXTBSY for shared libraries or not. > Maybe there are some legitimate reasons for writing to an open shared > library, such as strip --strip-debug on the C library as a contrived > example? I don't buy it. The glibc web site (http://www.gnu.org/software/libc/resources.html) says that installing over a live system (presumably they mean without using a package manager) is a bad idea. -- Matt
