If posix_fallocate is available, use it instead of ftruncate. Unlike
ftruncate, when posix_fallocate succeeds, it guarantees that you cannot
run out of disk space, when later writing to the mmap()'ed file.
With posix_fallocate, if os_create_anonymous_file() succeeds, the
program cannot get a SIGBUS later from accessing this file via mmap. If
there is insufficient disk space, the function fails and errno is set to
ENOSPC.
This is useful on systems, that limit the available buffer space by
having XDG_RUNTIME_DIR on a small tmpfs.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
AC_USE_SYSTEM_EXTENSIONS enables _XOPEN_SOURCE, _GNU_SOURCE and similar
macros to expose the largest extent of functionality supported by the
underlying system. This is required since these macros are often
limiting rather than merely additive, e.g. _XOPEN_SOURCE will actually
on some systems hide declarations which are not part of the X/Open spec.
Since this goes into config.h rather than the command line, ensure all
source is consistently including config.h before anything else,
including system libraries. This doesn't need to be guarded by a
HAVE_CONFIG_H ifdef, which was only ever a hangover from the X.Org
modular transition.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
[pq: rebased and converted more files]
We had duplicated code in many places, using hardcoded paths for
temporary files into more than one path. Some cases did not bother with
O_CLOEXEC, and all hardcoded paths that might not exist.
Add an OS helper function for creating a unique anonymous file with
close-on-exec semantics. The helper uses $XDG_RUNTIME_DIR as the
directory for a file.
This patch unifies the buffer file creation in both Weston and the
clients.
As simple clients are better not linking to libshared, as it would
require e.g. Cairo, they pull the OS compatibility code directly.
Android does not have mkostemp(), so a configure test is added for it,
and a fallback used if it is not available.
Changes in v2:
remove all the alternate possible directory definitions and use
XDG_RUNTIME_DIR only, and fail is it is not set.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
Pekka Paalanen