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| author | Paul Eggert <eggert@cs.ucla.edu> | 2020-12-24 11:38:48 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2020-12-24 12:06:48 -0800 |
| commit | f58714504e607a7c9d631073a356b2cd3cbf96c7 (patch) | |
| tree | c1f6d14c4920f4effa37ba1f1595dc717a0e91f0 /m4 | |
| parent | 6c98a29696b591c9a357183fac657f5547b6118a (diff) | |
| download | gnulib-f58714504e607a7c9d631073a356b2cd3cbf96c7.tar.gz | |
canonicalize: prefer faccessat to stat
A proper faccessat doesn't have the EOVERFLOW problem, and can be
more efficient as it needn't gather data from the filesystem to
fill in struct stat. So use stat only if faccessat is absent,
or when checking for symlink loops in canonicalize.c.
* lib/canonicalize-lgpl.c, lib/canonicalize.c:
Include fcntl.h, for AT_EACCESS.
(FACCESSAT_NEVER_EOVERFLOWS): Default to false.
(file_accessible): New function, based on faccessat but with
a fallback to stat and with an EOVERFLOW workaround.
(dir_check): Use it.
(dir_suffix): New static constant.
* lib/canonicalize-lgpl.c (FACCESSAT_NEVER_EOVERFLOWS) [_LIBC]:
Use __ASSUME_FACCESSAT2 to set FACCESSAT_NEVER_EOVERFLOWS
(__faccessat) [!_LIBC]: Define.
(realpath_stk): Use dir_suffix now.
* lib/canonicalize.c (canonicalize_filename_mode_stk):
If logical, don't check each component's existence; just check
at the end, as that's enough.
* m4/canonicalize.m4 (gl_FUNC_CANONICALIZE_FILENAME_MODE)
(gl_CANONICALIZE_LGPL_SEPARATE):
Require gl_FUNC_FACCESSAT_EOVERFLOW,
gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, and check for faccessat.
(gl_CANONICALIZE_LGPL_SEPARATE): Do not check for readlink,
as the code does not use HAVE_READLINK.
* modules/canonicalize, modules/canonicalize-lgpl (Files):
Add m4/faccessat.m4, m4/lstat.m4.
(Depends-on): Add fcntl-lh.
Diffstat (limited to 'm4')
| -rw-r--r-- | m4/canonicalize.m4 | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/m4/canonicalize.m4 b/m4/canonicalize.m4 index 14ea3e12fa..c8da4dfcb6 100644 --- a/m4/canonicalize.m4 +++ b/m4/canonicalize.m4 @@ -1,4 +1,4 @@ -# canonicalize.m4 serial 33 +# canonicalize.m4 serial 34 dnl Copyright (C) 2003-2007, 2009-2020 Free Software Foundation, Inc. @@ -11,7 +11,9 @@ dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_FUNC_CANONICALIZE_FILENAME_MODE], [ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) - AC_CHECK_FUNCS_ONCE([canonicalize_file_name]) + AC_REQUIRE([gl_FUNC_FACCESSAT_EOVERFLOW]) + AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK]) + AC_CHECK_FUNCS_ONCE([canonicalize_file_name faccessat]) AC_REQUIRE([gl_DOUBLE_SLASH_ROOT]) AC_REQUIRE([gl_FUNC_REALPATH_WORKS]) if test $ac_cv_func_canonicalize_file_name = no; then @@ -56,7 +58,9 @@ AC_DEFUN([gl_CANONICALIZE_LGPL], AC_DEFUN([gl_CANONICALIZE_LGPL_SEPARATE], [ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) - AC_CHECK_FUNCS_ONCE([canonicalize_file_name readlink]) + AC_REQUIRE([gl_FUNC_FACCESSAT_EOVERFLOW]) + AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK]) + AC_CHECK_FUNCS_ONCE([canonicalize_file_name faccessat]) dnl On native Windows, we use _getcwd(), regardless whether getcwd() is dnl available through the linker option '-loldnames'. |