unpack: keep conf_files replaced with symlinks, unpack as .new-pkgver

include/xbps_api_impl.h

@@ -115,7 +115,7 @@ int HIDDEN xbps_cb_message(struct xbps_handle *, xbps_dictionary_t, const char *
 int HIDDEN xbps_entry_is_a_conf_file(xbps_dictionary_t, const char *);
 int HIDDEN xbps_entry_install_conf_file(struct xbps_handle *, xbps_dictionary_t,
 		xbps_dictionary_t, struct archive_entry *, const char *,
-		const char *);
+		const char *, bool);
 int HIDDEN xbps_repository_find_deps(struct xbps_handle *, xbps_array_t,
 		xbps_dictionary_t);
 xbps_dictionary_t HIDDEN xbps_find_virtualpkg_in_conf(struct xbps_handle *,

lib/package_config_files.c

@@ -63,7 +63,8 @@ xbps_entry_install_conf_file(struct xbps_handle *xhp,
 			     xbps_dictionary_t pkg_filesd,
 			     struct archive_entry *entry,
 			     const char *entry_pname,
-			     const char *pkgver)
+			     const char *pkgver,
+			     bool symlink)
 {
 	xbps_object_t obj, obj2;
 	xbps_object_iterator_t iter, iter2;
@@ -87,9 +88,10 @@ xbps_entry_install_conf_file(struct xbps_handle *xhp,
 	xbps_dbg_printf(xhp, "%s: processing conf_file %s\n",
 	    pkgver, entry_pname);
 
-	if (pkg_filesd == NULL) {
+	if (pkg_filesd == NULL || symlink) {
 		/*
-		 * File exists on disk but it's not managed by the same package.
+		 * 1. File exists on disk but it's not managed by the same package.
+		 * 2. File exists on disk as symlink.
 		 * Install it as file.new-<version>.
 		 */
 		version = xbps_pkg_version(pkgver);

lib/package_unpack.c

@@ -87,7 +87,7 @@ unpack_archive(struct xbps_handle *xhp,
 	const char *file, *entry_pname, *transact, *binpkg_pkgver;
 	char *pkgname, *buf;
 	int ar_rv, rv, error, entry_type, flags;
-	bool preserve, update, file_exists;
+	bool preserve, update, file_exists, keep_conf_file;
 	bool skip_extract, force, xucd_stats;
 	uid_t euid;
 
@@ -287,7 +287,7 @@ unpack_archive(struct xbps_handle *xhp,
 		 * doesn't match, in that case overwrite the file.
 		 * Otherwise skip extracting it.
 		 */
-		skip_extract = file_exists = false;
+		skip_extract = file_exists = keep_conf_file = false;
 		if (lstat(entry_pname, &st) == 0)
 			file_exists = true;
 		/*
@@ -303,32 +303,41 @@ unpack_archive(struct xbps_handle *xhp,
 			    "it's preserved.\n", pkgver, entry_pname);
 			continue;
 		}
+
+		/*
+		 * Check if current entry is a configuration file,
+		 * that should be kept.
+		 */
+		if (!force && (entry_type == AE_IFREG)) {
+			buf = strchr(entry_pname, '.') + 1;
+			assert(buf != NULL);
+			keep_conf_file = xbps_entry_is_a_conf_file(binpkg_filesd, buf);
+		}
+
 		/*
 		 * If file to be extracted does not match the file type of
-		 * file currently stored on disk, remove file on disk.
+		 * file currently stored on disk and is not a conf file
+		 * that should be kept, remove file on disk.
 		 */
-		if (file_exists &&
+		if (file_exists && !keep_conf_file &&
 		    ((entry_statp->st_mode & S_IFMT) != (st.st_mode & S_IFMT)))
 			(void)remove(entry_pname);
 
 		if (!force && (entry_type == AE_IFREG)) {
-			buf = strchr(entry_pname, '.') + 1;
-			assert(buf != NULL);
-			if (file_exists && S_ISREG(st.st_mode)) {
+			if (file_exists && (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode))) {
 				/*
-				 * Handle configuration files. Check if current
-				 * entry is a configuration file and take action
-				 * if required. Skip packages that don't have
-				 * "conf_files" array on its XBPS_PKGPROPS
+				 * Handle configuration files.
+				 * Skip packages that don't have "conf_files"
+				 * array on its XBPS_PKGPROPS
 				 * dictionary.
 				 */
-				if (xbps_entry_is_a_conf_file(binpkg_filesd, buf)) {
+				if (keep_conf_file) {
 					if (xhp->unpack_cb != NULL)
 						xucd.entry_is_conf = true;
 
 					rv = xbps_entry_install_conf_file(xhp,
 					    binpkg_filesd, pkg_filesd, entry,
-					    entry_pname, pkgver);
+					    entry_pname, pkgver, S_ISLNK(st.st_mode));
 					if (rv == -1) {
 						/* error */
 						goto out;

tests/xbps/libxbps/shell/conf_files_test.sh

@@ -165,9 +165,70 @@ tc4_body() {
 	atf_check_equal $rval 0
 }
 
+# 5th test: configuration file replaced with symlink on disk, modified on upgrade.
+#	result: install new file as "<conf_file>.new-<version>".
+atf_test_case tc5
+
+tc5_head() {
+	atf_set "descr" "Tests for configuration file handling: on-disk replaced with symlink, upgrade modified"
+}
+
+tc5_body() {
+	mkdir repo
+	cd repo
+	mkdir pkg_a
+	echo "fooblah" > pkg_a/cf1.conf
+	chmod 644 pkg_a/cf1.conf
+	xbps-create -A noarch -n a-0.1_1 -s "pkg a" --config-files "/cf1.conf" pkg_a
+	atf_check_equal $? 0
+	rm -rf pkg_a
+	xbps-rindex -d -a $PWD/*.xbps
+	atf_check_equal $? 0
+	xbps-install -C null.conf -r rootdir --repository=$PWD -yvd a
+	atf_check_equal $? 0
+
+	mv rootdir/cf1.conf rootdir/foobar.conf
+	ln -sf foobar.conf rootdir/cf1.conf
+	sed -e 's,fooblah,blahfoo,' -i rootdir/foobar.conf
+	chmod 644 rootdir/foobar.conf
+
+	mkdir pkg_a
+	echo "bazbar" > pkg_a/cf1.conf
+	chmod 644 pkg_a/cf1.conf
+	xbps-create -A noarch -n a-0.2_1 -s "pkg a" --config-files "/cf1.conf" pkg_a
+	atf_check_equal $? 0
+
+	xbps-rindex -d -a $PWD/*.xbps
+	atf_check_equal $? 0
+	rm -rf pkg_a
+
+	xbps-install -C null.conf -r rootdir --repository=$PWD -yuvd
+	atf_check_equal $? 0
+
+	ls -lsa rootdir
+	test -h rootdir/cf1.conf
+	atf_check_equal $? 0
+
+	result="$(cat rootdir/cf1.conf)"
+	rval=1
+	if [ "${result}" = "blahfoo" ]; then
+		rval=0
+	fi
+
+	echo "result: ${result}"
+	echo "expected: blahfoo"
+	atf_check_equal $rval 0
+	rval=1
+	if [ -s rootdir/cf1.conf.new-0.2_1 ]; then
+		rval=0
+	fi
+	atf_check_equal $rval 0
+}
+
 atf_init_test_cases() {
 	atf_add_test_case tc1
 	atf_add_test_case tc2
 	atf_add_test_case tc3
 	atf_add_test_case tc4
+	atf_add_test_case tc5
 }