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Diffstat (limited to 'm4/lstat.m4')
-rw-r--r-- | m4/lstat.m4 | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/m4/lstat.m4 b/m4/lstat.m4 new file mode 100644 index 00000000..b83858bd --- /dev/null +++ b/m4/lstat.m4 @@ -0,0 +1,70 @@ +# serial 24 + +# Copyright (C) 1997-2001, 2003-2012 Free Software Foundation, Inc. +# +# This file is free software; the Free Software Foundation +# gives unlimited permission to copy and/or distribute it, +# with or without modifications, as long as this notice is preserved. + +dnl From Jim Meyering. + +AC_DEFUN([gl_FUNC_LSTAT], +[ + AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS]) + dnl If lstat does not exist, the replacement <sys/stat.h> does + dnl "#define lstat stat", and lstat.c is a no-op. + AC_CHECK_FUNCS_ONCE([lstat]) + if test $ac_cv_func_lstat = yes; then + AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK]) + if test $gl_cv_func_lstat_dereferences_slashed_symlink = no; then + REPLACE_LSTAT=1 + fi + else + HAVE_LSTAT=0 + fi +]) + +# Prerequisites of lib/lstat.c. +AC_DEFUN([gl_PREREQ_LSTAT], +[ + AC_REQUIRE([AC_C_INLINE]) + : +]) + +AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK], +[ + dnl We don't use AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK any more, because it + dnl is no longer maintained in Autoconf and because it invokes AC_LIBOBJ. + AC_CACHE_CHECK([whether lstat correctly handles trailing slash], + [gl_cv_func_lstat_dereferences_slashed_symlink], + [rm -f conftest.sym conftest.file + echo >conftest.file + if test "$as_ln_s" = "ln -s" && ln -s conftest.file conftest.sym; then + AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [AC_INCLUDES_DEFAULT], + [[struct stat sbuf; + /* Linux will dereference the symlink and fail, as required by + POSIX. That is better in the sense that it means we will not + have to compile and use the lstat wrapper. */ + return lstat ("conftest.sym/", &sbuf) == 0; + ]])], + [gl_cv_func_lstat_dereferences_slashed_symlink=yes], + [gl_cv_func_lstat_dereferences_slashed_symlink=no], + [# When cross-compiling, be pessimistic so we will end up using the + # replacement version of lstat that checks for trailing slashes and + # calls lstat a second time when necessary. + gl_cv_func_lstat_dereferences_slashed_symlink=no + ]) + else + # If the 'ln -s' command failed, then we probably don't even + # have an lstat function. + gl_cv_func_lstat_dereferences_slashed_symlink=no + fi + rm -f conftest.sym conftest.file + ]) + test $gl_cv_func_lstat_dereferences_slashed_symlink = yes && + AC_DEFINE_UNQUOTED([LSTAT_FOLLOWS_SLASHED_SYMLINK], [1], + [Define to 1 if 'lstat' dereferences a symlink specified + with a trailing slash.]) +]) |