summaryrefslogtreecommitdiffstats
path: root/gl/m4/chown.m4
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--gl/m4/chown.m4218
1 files changed, 218 insertions, 0 deletions
diff --git a/gl/m4/chown.m4 b/gl/m4/chown.m4
new file mode 100644
index 0000000..56dda0a
--- /dev/null
+++ b/gl/m4/chown.m4
@@ -0,0 +1,218 @@
+# serial 35
+# Determine whether we need the chown wrapper.
+
+dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2022 Free Software
+dnl 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.
+
+# chown should accept arguments of -1 for uid and gid, and it should
+# dereference symlinks. If it doesn't, arrange to use the replacement
+# function.
+
+# From Jim Meyering.
+
+# This is taken from the following Autoconf patch:
+# https://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=7fbb553727ed7e0e689a17594b58559ecf3ea6e9
+AC_DEFUN([AC_FUNC_CHOWN],
+[
+ AC_REQUIRE([AC_TYPE_UID_T])dnl
+ AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+ AC_CHECK_HEADERS([unistd.h])
+ AC_CACHE_CHECK([for working chown],
+ [ac_cv_func_chown_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [AC_INCLUDES_DEFAULT
+ [#include <fcntl.h>
+ ]GL_MDA_DEFINES],
+ [[
+ char *f = "conftest.chown";
+ struct stat before, after;
+
+ if (creat (f, 0600) < 0)
+ return 1;
+ if (stat (f, &before) < 0)
+ return 1;
+ if (chown (f, (uid_t) -1, (gid_t) -1) == -1)
+ return 1;
+ if (stat (f, &after) < 0)
+ return 1;
+ return ! (before.st_uid == after.st_uid && before.st_gid == after.st_gid);
+ ]])
+ ],
+ [ac_cv_func_chown_works=yes],
+ [ac_cv_func_chown_works=no],
+ [case "$host_os" in # ((
+ # Guess yes on Linux systems.
+ linux-* | linux) ac_cv_func_chown_works="guessing yes" ;;
+ # Guess yes on glibc systems.
+ *-gnu* | gnu*) ac_cv_func_chown_works="guessing yes" ;;
+ # Guess no on native Windows.
+ mingw*) ac_cv_func_chown_works="guessing no" ;;
+ # If we don't know, obey --enable-cross-guesses.
+ *) ac_cv_func_chown_works="$gl_cross_guess_normal" ;;
+ esac
+ ])
+ rm -f conftest.chown
+ ])
+ case "$ac_cv_func_chown_works" in
+ *yes)
+ AC_DEFINE([HAVE_CHOWN], [1],
+ [Define to 1 if your system has a working `chown' function.])
+ ;;
+ esac
+])# AC_FUNC_CHOWN
+
+AC_DEFUN_ONCE([gl_FUNC_CHOWN],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ AC_REQUIRE([AC_TYPE_UID_T])
+ AC_REQUIRE([AC_FUNC_CHOWN])
+ AC_REQUIRE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CHECK_FUNCS_ONCE([chown fchown])
+
+ dnl mingw lacks chown altogether.
+ if test $ac_cv_func_chown = no; then
+ HAVE_CHOWN=0
+ else
+ dnl Some old systems treated chown like lchown.
+ case "$gl_cv_func_chown_follows_symlink" in
+ *yes) ;;
+ *) REPLACE_CHOWN=1 ;;
+ esac
+
+ dnl Some old systems tried to use uid/gid -1 literally.
+ case "$ac_cv_func_chown_works" in
+ *no)
+ AC_DEFINE([CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE], [1],
+ [Define if chown is not POSIX compliant regarding IDs of -1.])
+ REPLACE_CHOWN=1
+ ;;
+ esac
+
+ dnl Solaris 9 ignores trailing slash.
+ dnl FreeBSD 7.2 mishandles trailing slash on symlinks.
+ dnl Likewise for AIX 7.1.
+ AC_CACHE_CHECK([whether chown honors trailing slash],
+ [gl_cv_func_chown_slash_works],
+ [touch conftest.file && rm -f conftest.link
+ AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+]GL_MDA_DEFINES],
+ [[if (symlink ("conftest.file", "conftest.link")) return 1;
+ if (chown ("conftest.link/", getuid (), getgid ()) == 0) return 2;
+ ]])],
+ [gl_cv_func_chown_slash_works=yes],
+ [gl_cv_func_chown_slash_works=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_chown_slash_works="guessing yes" ;;
+ # Guess yes on musl systems.
+ *-musl*) gl_cv_func_chown_slash_works="guessing yes" ;;
+ # If we don't know, obey --enable-cross-guesses.
+ *) gl_cv_func_chown_slash_works="$gl_cross_guess_normal" ;;
+ esac
+ ])
+ rm -f conftest.link conftest.file])
+ case "$gl_cv_func_chown_slash_works" in
+ *yes) ;;
+ *)
+ AC_DEFINE([CHOWN_TRAILING_SLASH_BUG], [1],
+ [Define to 1 if chown mishandles trailing slash.])
+ REPLACE_CHOWN=1
+ ;;
+ esac
+
+ dnl OpenBSD fails to update ctime if ownership does not change.
+ AC_CACHE_CHECK([whether chown always updates ctime],
+ [gl_cv_func_chown_ctime_works],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+]GL_MDA_DEFINES],
+ [[struct stat st1, st2;
+ if (close (creat ("conftest.file", 0600))) return 1;
+ if (stat ("conftest.file", &st1)) return 2;
+ sleep (1);
+ if (chown ("conftest.file", st1.st_uid, st1.st_gid)) return 3;
+ if (stat ("conftest.file", &st2)) return 4;
+ if (st2.st_ctime <= st1.st_ctime) return 5;
+ ]])],
+ [gl_cv_func_chown_ctime_works=yes],
+ [gl_cv_func_chown_ctime_works=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_chown_ctime_works="guessing yes" ;;
+ # Guess yes on musl systems.
+ *-musl*) gl_cv_func_chown_ctime_works="guessing yes" ;;
+ # If we don't know, obey --enable-cross-guesses.
+ *) gl_cv_func_chown_ctime_works="$gl_cross_guess_normal" ;;
+ esac
+ ])
+ rm -f conftest.file])
+ case "$gl_cv_func_chown_ctime_works" in
+ *yes) ;;
+ *)
+ AC_DEFINE([CHOWN_CHANGE_TIME_BUG], [1], [Define to 1 if chown fails
+ to change ctime when at least one argument was not -1.])
+ REPLACE_CHOWN=1
+ ;;
+ esac
+ fi
+])
+
+# Determine whether chown follows symlinks (it should).
+AC_DEFUN_ONCE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
+[
+ AC_CACHE_CHECK(
+ [whether chown dereferences symlinks],
+ [gl_cv_func_chown_follows_symlink],
+ [
+ AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+]GL_MDA_DEFINES[
+ int
+ main ()
+ {
+ int result = 0;
+ char const *dangling_symlink = "conftest.dangle";
+
+ unlink (dangling_symlink);
+ if (symlink ("conftest.no-such", dangling_symlink))
+ abort ();
+
+ /* Exit successfully on a conforming system,
+ i.e., where chown must fail with ENOENT. */
+ if (chown (dangling_symlink, getuid (), getgid ()) == 0)
+ result |= 1;
+ if (errno != ENOENT)
+ result |= 2;
+ return result;
+ }
+ ]])],
+ [gl_cv_func_chown_follows_symlink=yes],
+ [gl_cv_func_chown_follows_symlink=no],
+ [gl_cv_func_chown_follows_symlink="guessing yes"]
+ )
+ ]
+ )
+
+ case "$gl_cv_func_chown_follows_symlink" in
+ *yes) ;;
+ *)
+ AC_DEFINE([CHOWN_MODIFIES_SYMLINK], [1],
+ [Define if chown modifies symlinks.])
+ ;;
+ esac
+])