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* etc/NEWS: Document this.
* nt/inc/unistd.h (O_NOFOLLOW): New macro.
* src/filelock.c: Include <c-ctype.h>.
(MAX_LFINFO): New top-level constant.
(lock_info_type): Remove members pid, boot_time.  Add members at,
dot, colon.  Change user member to be the entire buffer, not a
pointer.  This allows us to handle the case where a foreign
pid or boot time exceeds the local range.  All uses changed.
(LINKS_MIGHT_NOT_WORK): New constant.
(FREE_LOCK_INFO): Remove, as the pieces no longer need freeing.
(defined_WINDOWSNT): Remove.
(MAKE_LOCK_NAME, file_in_lock_file_name):
Always use .#FILE (not .#-FILE) for the file lock,
even if it is a regular file.
(rename_lock_file): New function.
(create_lock_file): Use it.
(create_lock_file, read_lock_data):
Prefer a symbolic link for the lock file, falling back on a
regular file if symlinks don't work.  Do not try to create
symlinks on MS-Windows, due to security hassles.  Stick with
POSIXish functions (open, read, write, close, fchmod, readlink, symlink,
link, rename, unlink, mkstemp) when creating locks, as a GNUish
host may be using a Windowsish file system, and cannot use
MS-Windows-only system calls.  Fall back on mktemp if mkstemp
doesn't work.  Don't fail merely because of a symlink-contents
length limit in the current file system; fall back on regular
files.  Increase the symlink contents length limit to 8 KiB, this
should be big enough for any real use and doesn't crunch the
stack.
(create_lock_file, lock_file_1, read_lock_data):
Simplify allocation of lock file buffers now that they fit in 8 KiB.
(lock_file_1): Return error number, not bool.  All callers changed.
(ELOOP): New macro, if not already defined.
(read_lock_data): Return size of lock file contents, not Lisp object.
All callers changed.  Handle a race condition if some other process
replaces a regular-file lock with a symlink lock or vice versa,
while we're trying to read the lock.
(current_lock_owner): Parse contents more carefully, to help avoid
confusing a regular-file lock with some other application's use
of the file.  Check for lock file contents being too long, or
not parsing correctly.
(current_lock_owner, lock_file):
Allow foreign pid and boot times that exceed the local range.
(current_lock_owner, lock_if_free, lock_file):
Simplify allocation of lock file contents.
* src/w32.c (sys_rename_replace): New function, containing most of
the contents of the old sys_rename.
(sys_rename): Use it.
(fchmod): New dummy function.
* src/w32.h (sys_rename_replace, fchmod): New decls.

Fixes: debbugs:13807

On my host, this speeds up directory-files-and-attributes by a
factor of 3, when applied to Emacs's src directory.
These functions are standardized by POSIX and are common these
days; fall back on a (slower) gnulib implementation if the host
is too old to supply them.
* .bzrignore: Add lib/dirent.h.
* lib/Makefile.am (libgnu_a_SOURCES): Add openat-die.c, save-cwd.c.
* lib/careadlinkat.c, lib/careadlinkat.h: Merge from gnulib,
incorporating: 2013-01-29 careadlinkat: do not provide careadlinkatcwd.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/dirent.in.h, lib/fdopendir.c, lib/fstatat.c, lib/openat-priv.h:
* lib/openat-proc.c, lib/openat.h, m4/dirent_h.m4, m4/fdopendir.m4:
* m4/fstatat.m4: New files, from gnulib.
* lib/openat-die.c, lib/save-cwd.c, lib/save-cwd.h: New files.
These last three are specific to Emacs and are not copied from gnulib.
They are simpler than the gnulib versions and are tuned for Emacs.
* admin/merge-gnulib (GNULIB_MODULES): Add fdopendir, fstatat, readlinkat.
(GNULIB_TOOL_FLAGS): Do not avoid at-internal, openat-h.
Avoid dup, open, opendir.
* nt/inc/sys/stat.h (fstatat):
* nt/inc/unistd.h (readlinkat): New decls.
* src/conf_post.h (GNULIB_SUPPORT_ONLY_AT_FDCWD): Remove.
* src/dired.c: Include <fcntl.h>.
(open_directory): New function, which uses open and fdopendir
rather than opendir.  DOS_NT platforms still use opendir, though.
(directory_files_internal, file_name_completion): Use it.
(file_attributes): New function, with most of the old Ffile_attributes.
(directory_files_internal, Ffile_attributes): Use it.
(file_attributes, file_name_completion_stat): First arg is now fd,
not dir name.  All uses changed.  Use fstatat rather than lstat +
stat.
(file_attributes): Use emacs_readlinkat rather than Ffile_symlink_p.
* src/fileio.c: Include <allocator.h>, <careadlinkat.h>.
(emacs_readlinkat): New function, with much of the old
Ffile_symlink_p, but with an fd argument for speed.
It uses readlinkat rather than careadlinkatcwd, so that it
need not assume the working directory.
(Ffile_symlink_p): Use it.
* src/filelock.c (current_lock_owner): Use emacs_readlinkat
rather than emacs_readlink.
* src/lisp.h (emacs_readlinkat): New decl.
(READLINK_BUFSIZE, emacs_readlink): Remove.
* src/sysdep.c: Do not include <allocator.h>, <careadlinkat.h>.
(emacs_norealloc_allocator, emacs_readlink): Remove.
This stuff is moved to fileio.c.
* src/w32.c (fstatat, readlinkat): New functions.
(careadlinkat): Don't check that fd == AT_FDCWD.
(careadlinkatcwd): Remove; no longer needed.

Fixes: debbugs:13539

 nt/inc/unistd.h (O_IGNORE_CTTY): Define, as it is unconditionally
 used in term.c.

 nt/inc/unistd.h (unsetenv): Provide a prototype.

 nt/inc/unistd.h: Don't include fcntl.h and don't define O_RDWR.

Fixes: debbugs:12881

* admin/CPP-DEFINES (O_RDONLY, O_RDWR, HAVE_FCNTL_H): Remove.
* admin/merge-gnulib (GNULIB_MODULES): Add fcntl-h.
* configure.ac: Do not check for fcntl.h.
* lib/gnulib.mk: Regenerate.
* lib-src/movemail.c, lib-src/update-game-score.c: Assume <fcntl.h> exists.
* nt/inc/sys/socket.h (O_NONBLOCK): Rename from O_NDELAY, since the
POSIX name for this flag is O_NONBLOCK.  All uses changed.
* nt/inc/unistd.h (O_RDWR, O_NOCTTY): New macros.  Like AT_FDCWD etc.
these really should be moved to a replacement <fcntl.h> if and
when that gets implemented.  In the meantime, include <fcntl.h>
to make sure we don't override its definitions.
* src/callproc.c (relocate_fd): Assume F_DUPFD.
* src/emacs.c, src/term.c (O_RDWR): Remove.
* src/keyboard.c (tty_read_avail_input): Use O_NONBLOCK rather than
O_NDELAY, since O_NONBLOCK is the standard name for this flag.
* src/nsterm.m: Assume <fcntl.h> exists.
* src/process.c (NON_BLOCKING_CONNECT, allocate_pty, create_process)
(create_pty, Fmake_network_process, server_accept_connection)
(wait_reading_process_output, init_process_emacs):
Assume O_NONBLOCK.
(wait_reading_process_output): Put in a special case for WINDOWSNT
to mimick the older behavior where it had O_NDELAY but not O_NONBLOCK.
It's not clear this is needed, but it's a more-conservative change.
(create_process): Assume FD_CLOEXEC.
(create_process, create_pty): Assume O_NOCTTY.
* src/sysdep.c (init_sys_modes, reset_sys_modes): Assume F_SETFL.
(reset_sys_modes): Use O_NONBLOCK rather than O_NDELAY.
Omit if not DOS_NT, since F_GETFL is not defined there.
(serial_open): Assume O_NONBLOCK and O_NOCTTY.
* src/term.c: Include <fcntl.h>, for flags like O_NOCTTY.
(O_NOCTTY): Remove.
(init_tty): Assume O_IGNORE_CTTY is defined to 0 on platforms that
lack it, since gnulib guarantees this.
* src/w32.c (fcntl): Test for O_NONBLOCK rather than O_NDELAY.

Fixes: debbugs:12881

 nt/inc/unistd.h (faccessat): Add prototype.
 (AT_FDCWD, AT_EACCESS, AT_SYMLINK_NOFOLLOW): New macros; the first
 2 moved from ms-w32.h.
 nt/inc/ms-w32.h (AT_FDCWD, AT_EACCESS, faccessat): Remove macros.

 src/w32.c (faccessat): Rename from sys_faccessat.  (No need to use a
 different name, as the MS runtime does not have such a function,
 and probably never will.)  All callers changed.  Ignore DIRFD
 value if PATH is an absolute file name, to match Posix spec
 better.  If AT_SYMLINK_NOFOLLOW is set in FLAGS, don't resolve
 symlinks.

Fixes: debbugs:12632

 nt/inc/unistd.h (tcgetpgrp, setsid): Provide prototypes.

 src/w32proc.c (getpgrp, setpgid): New functions.

 nt/inc/unistd.h (setpgid, getpgrp): Provide prototypes.
 nt/config.nt (GETPGRP_VOID): Define to 1.

Do not try to redefine the 'abort' function.  Instead, redo
the code so that it calls 'emacs_abort' rather than 'abort'.
This removes the need for the NO_ABORT configure-time macro
and makes it easier to change the abort code to do a backtrace.
* configure.ac (NO_ABRT): Remove.
* admin/CPP-DEFINES (NO_ABORT): Remove.
* nt/inc/ms-w32.h (w32_abort) [HAVE_NTGUI]: Remove.
* src/.gdbinit: Just stop at emacs_abort, not at w32_abort or abort.
* src/emacs.c (abort) [!DOS_NT && !NO_ABORT]:
Remove; sysdep.c's emacs_abort now takes its place.
* src/lisp.h (emacs_abort): New decl.  All calls from Emacs code to
'abort' changed to use 'emacs_abort'.
* src/msdos.c (dos_abort) [defined abort]: Remove; not used.
(abort) [!defined abort]: Rename to ...
(emacs_abort): ... new name.
* src/sysdep.c (emacs_abort) [!HAVE_NTGUI]: New function, taking
the place of the old 'abort' in emacs.c.
* src/w32.c, src/w32fns.c (abort): Do not #undef.
* src/w32.c (emacs_abort): Rename from w32_abort.

 src/w32.c (symlink, readlink): New stub functions.
 nt/inc/unistd.h (readlink, symlink): Declare prototypes.