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8654f9d7d6
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
65 lines
2.5 KiB
C
65 lines
2.5 KiB
C
/* Internals for openat-like functions.
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Copyright (C) 2005-2006, 2009-2013 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* written by Jim Meyering */
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#ifndef _GL_HEADER_OPENAT_PRIV
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#define _GL_HEADER_OPENAT_PRIV
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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/* Maximum number of bytes that it is safe to allocate as a single
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array on the stack, and that is known as a compile-time constant.
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The assumption is that we'll touch the array very quickly, or a
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temporary very near the array, provoking an out-of-memory trap. On
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some operating systems, there is only one guard page for the stack,
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and a page size can be as small as 4096 bytes. Subtract 64 in the
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hope that this will let the compiler touch a nearby temporary and
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provoke a trap. */
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#define SAFER_ALLOCA_MAX (4096 - 64)
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#define SAFER_ALLOCA(m) ((m) < SAFER_ALLOCA_MAX ? (m) : SAFER_ALLOCA_MAX)
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#if defined PATH_MAX
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# define OPENAT_BUFFER_SIZE SAFER_ALLOCA (PATH_MAX)
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#elif defined _XOPEN_PATH_MAX
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# define OPENAT_BUFFER_SIZE SAFER_ALLOCA (_XOPEN_PATH_MAX)
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#else
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# define OPENAT_BUFFER_SIZE SAFER_ALLOCA (1024)
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#endif
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char *openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file);
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/* Trying to access a BUILD_PROC_NAME file will fail on systems without
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/proc support, and even on systems *with* ProcFS support. Return
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nonzero if the failure may be legitimate, e.g., because /proc is not
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readable, or the particular .../fd/N directory is not present. */
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#define EXPECTED_ERRNO(Errno) \
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((Errno) == ENOTDIR || (Errno) == ENOENT \
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|| (Errno) == EPERM || (Errno) == EACCES \
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|| (Errno) == ENOSYS /* Solaris 8 */ \
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|| (Errno) == EOPNOTSUPP /* FreeBSD */)
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/* Wrapper function shared among linkat and renameat. */
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int at_func2 (int fd1, char const *file1,
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int fd2, char const *file2,
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int (*func) (char const *file1, char const *file2));
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#endif /* _GL_HEADER_OPENAT_PRIV */
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