diff options
Diffstat (limited to 'm4/fchownat.m4')
| -rw-r--r-- | m4/fchownat.m4 | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/m4/fchownat.m4 b/m4/fchownat.m4 new file mode 100644 index 0000000..3d20d53 --- /dev/null +++ b/m4/fchownat.m4 @@ -0,0 +1,111 @@ +# fchownat.m4 serial 7 +dnl Copyright (C) 2004-2022 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +# Written by Jim Meyering. + +# If we have the fchownat function, and it has the bug (in glibc-2.4) +# that it dereferences symlinks even with AT_SYMLINK_NOFOLLOW, then +# use the replacement function. +# Also if the fchownat function, like chown, has the trailing slash bug, +# use the replacement function. +# Also use the replacement function if fchownat is simply not available. +AC_DEFUN([gl_FUNC_FCHOWNAT], +[ + AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + AC_REQUIRE([gl_FUNC_CHOWN]) + AC_CHECK_FUNC([fchownat], + [gl_FUNC_FCHOWNAT_DEREF_BUG( + [REPLACE_FCHOWNAT=1 + AC_DEFINE([FCHOWNAT_NOFOLLOW_BUG], [1], + [Define to 1 if your platform has fchownat, but it cannot + perform lchown tasks.]) + ]) + gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG( + [REPLACE_FCHOWNAT=1 + AC_DEFINE([FCHOWNAT_EMPTY_FILENAME_BUG], [1], + [Define to 1 if your platform has fchownat, but it does + not reject an empty file name.]) + ]) + if test $REPLACE_CHOWN = 1; then + REPLACE_FCHOWNAT=1 + fi], + [HAVE_FCHOWNAT=0]) +]) + +# gl_FUNC_FCHOWNAT_DEREF_BUG([ACTION-IF-BUGGY[, ACTION-IF-NOT_BUGGY]]) +AC_DEFUN([gl_FUNC_FCHOWNAT_DEREF_BUG], +[ + dnl Persuade glibc's <unistd.h> to declare fchownat(). + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + + AC_CACHE_CHECK([whether fchownat works with AT_SYMLINK_NOFOLLOW], + [gl_cv_func_fchownat_nofollow_works], + [ + gl_dangle=conftest.dangle + # Remove any remnants of a previous test. + rm -f $gl_dangle + # Arrange for deletion of the temporary file this test creates. + ac_clean_files="$ac_clean_files $gl_dangle" + ln -s conftest.no-such $gl_dangle + AC_RUN_IFELSE( + [AC_LANG_SOURCE( + [[ +#include <fcntl.h> +#include <unistd.h> +/* Android 4.3 declares fchownat() in <sys/stat.h> instead. */ +#include <sys/stat.h> +#include <stdlib.h> +#include <errno.h> +#include <sys/types.h> +int +main () +{ + return (fchownat (AT_FDCWD, "$gl_dangle", (uid_t)(-1), getgid (), + AT_SYMLINK_NOFOLLOW) != 0 + && errno == ENOENT); +} + ]])], + [gl_cv_func_fchownat_nofollow_works=yes], + [gl_cv_func_fchownat_nofollow_works=no], + [gl_cv_func_fchownat_nofollow_works="$gl_cross_guess_normal"]) + ]) + AS_IF([test "$gl_cv_func_fchownat_nofollow_works" != yes], [$1], [$2]) +]) + +# gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG([ACTION-IF-BUGGY[, ACTION-IF-NOT_BUGGY]]) +AC_DEFUN([gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG], +[ + dnl Persuade glibc's <unistd.h> to declare fchownat(). + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + + AC_CACHE_CHECK([whether fchownat works with an empty file name], + [gl_cv_func_fchownat_empty_filename_works], + [AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include <unistd.h> + #include <fcntl.h> + /* Android 4.3 declares fchownat() in <sys/stat.h> instead. */ + #include <sys/stat.h> + ]GL_MDA_DEFINES], + [[int fd; + int ret; + if (mkdir ("conftestdir", 0700) < 0) + return 2; + fd = open ("conftestdir", O_RDONLY); + if (fd < 0) + return 3; + ret = fchownat (fd, "", (uid_t)(-1), (gid_t)(-1), 0); + close (fd); + rmdir ("conftestdir"); + return ret == 0; + ]])], + [gl_cv_func_fchownat_empty_filename_works=yes], + [gl_cv_func_fchownat_empty_filename_works=no], + [gl_cv_func_fchownat_empty_filename_works="$gl_cross_guess_normal"]) + ]) + AS_IF([test "$gl_cv_func_fchownat_empty_filename_works" != yes], [$1], [$2]) +]) |