mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-29 00:01:12 +00:00
27cb2bb93d
MAP_FIXED is defined to silently replace any existing mappings at the address range being mapped over. This, however, is a dangerous, and only rarely desired behavior. Various Unix systems provide replacements or additions to MAP_FIXED: * SerenityOS and Linux provide MAP_FIXED_NOREPLACE. If the address space already contains a mapping in the requested range, Linux returns EEXIST. SerenityOS returns ENOMEM, however that is a bug, as the MAP_FIXED_NOREPLACE implementation is intended to be compatible with Linux. * FreeBSD provides the MAP_EXCL flag that has to be used in combination with MAP_FIXED. It returns EINVAL if the requested range already contains existing mappings. This is directly analogous to the O_EXCL flag in the open () call. * DragonFly BSD, NetBSD, and OpenBSD provide MAP_TRYFIXED, but with different semantics. DragonFly BSD returns ENOMEM if the requested range already contains existing mappings. NetBSD does not return an error, but instead creates the mapping at a different address if the requested range contains mappings. OpenBSD behaves the same, but also notes that this is the default behavior even without MAP_TRYFIXED (which is the case on the Hurd too). Since the Hurd leans closer to the BSD side, add MAP_EXCL as the primary API to request the behavior of not replacing existing mappings. Declare MAP_FIXED_NOREPLACE and MAP_TRYFIXED as aliases of (MAP_FIXED|MAP_EXCL), so any existing software that checks for either of those macros will pick them up automatically. For compatibility with Linux, return EEXIST if a mapping already exists. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> Message-Id: <20230625231751.404120-5-bugaevc@gmail.com> |
||
|---|---|---|
| .. | ||
| htl | ||
| hurd | ||
| i386 | ||
| include | ||
| sys | ||
| x86 | ||
| x86_64 | ||
| _strerror.c | ||
| adjtime.c | ||
| clock_gettime.c | ||
| clock_nanosleep.c | ||
| configure | ||
| configure.ac | ||
| getloadavg.c | ||
| getpagesize.c | ||
| getsysstats.c | ||
| libc-lock.h | ||
| libmachuser.abilist | ||
| mach_rpc.h | ||
| Makefile | ||
| mprotect.c | ||
| msync.c | ||
| munmap.c | ||
| pagecopy.h | ||
| readonly-area.c | ||
| sched_yield.c | ||
| sleep.c | ||
| strerror_l.c | ||
| Subdirs | ||
| sysdep.h | ||
| thread_state.h | ||
| usleep.c | ||
| xpg-strerror.c | ||