ostree: move admindir to /etc/alternatives.admindir

`ostree container commit` wipes /var and thereby erases the data in
/var/lib/alternatives; the directory used to store configs/symlinks of
alternatives.

/var is not a good place for storing such configs since it won't receive
updates on bootc images either.  We need to move to another location.

Hence, use /etc/alternatives.admindir when running on an ostree-based
system unless /var/lib/alternatives is already present; a user may have
worked around the problem.  This way we enable alternatives to work on
ostree-based systems without breaking backwards compat.

Fixes: #9
Signed-off-by: Valentin Rothberg <[email protected]>

Makefile

@@ -55,7 +55,6 @@ install:
 	[ -d $(DESTDIR)/$(SBINDIR) ] || mkdir -p $(DESTDIR)/$(SBINDIR)
 	[ -d $(DESTDIR)/$(MANDIR) ] || mkdir -p $(DESTDIR)/$(MANDIR)
 	[ -d $(DESTDIR)/$(MANDIR)/man8 ] || mkdir -p $(DESTDIR)/$(MANDIR)/man8
-	[ -d $(DESTDIR)/$(ALTDIR) ] || mkdir -p -m 755 $(DESTDIR)/$(ALTDIR)
 	[ -d $(DESTDIR)/$(ALTDATADIR) ] || mkdir -p -m 755 $(DESTDIR)/$(ALTDATADIR)
 	[ -d $(DESTDIR)/$(SYSTEMDUTILDIR) ] || mkdir -p -m 755 $(DESTDIR)/$(SYSTEMDUTILDIR)
 

alternatives.8

@@ -214,6 +214,7 @@ A directory, by default
 containing
 .BR alternatives '
 state information.
+/etc/alternatives.admindir on OSTree-based systems.
 .TP
 link group
 A set of related symlinks, intended to be updated as a group.
@@ -416,6 +417,7 @@ option.
 .TP
 .I /var/lib/alternatives/
 The default administration directory.
+/etc/alternatives.admindir on OSTree-based systems.
 Can be overridden by the
 .B --admindir
 option.

alternatives.c

@@ -1290,6 +1290,33 @@ static int listServices(const char *altDir, const char *stateDir, int flags) {
     return 0;
 }
 
+int dirExists(const char *path) {
+    struct stat sb;
+
+    if (stat(path, &sb)) { 
+        if (errno == ENOENT) {
+            return 0;
+        }
+    }
+
+    if (!S_ISDIR(sb.st_mode) || access(path, F_OK)) {
+        fprintf(stderr, _("admindir %s invalid\n"), path);
+        exit(2);
+    }
+
+    return 1;
+}
+
+int canUseAlternativeAdminDirUnderOSTree() {
+    if (dirExists("/var/lib/alternatives")) { return 0; }
+
+    if (fileExists("/run/ostree-booted") || isLink("/ostree")) {
+        return 1;
+    }
+
+    return 0;
+}
+
 int main(int argc, const char **argv) {
     const char **nextArg;
     char *end;
@@ -1300,18 +1327,19 @@ int main(int argc, const char **argv) {
     struct alternative newAlt = {-1, {NULL, NULL, NULL}, NULL, NULL, 0, NULL};
     int flags = 0;
     char *altDir = "/etc/alternatives";
-    char *stateDir = "/var/lib/alternatives";
+    char *stateDir= NULL;
     struct stat sb;
     struct linkSet newSet = {NULL, NULL, NULL};
 
+
     setlocale(LC_ALL, "");
     bindtextdomain("chkconfig", "/usr/share/locale");
     textdomain("chkconfig");
 
     if (!argv[1])
         return usage(2);
 
-    nextArg = argv + 1;
+    nextArg = argv + 1= NULL;
     while (*nextArg) {
         if (!strcmp(*nextArg, "--install")) {
             if (mode != MODE_UNKNOWN && mode != MODE_FOLLOWER)
@@ -1428,6 +1456,19 @@ int main(int argc, const char **argv) {
         exit(2);
     }
 
+    if ((stateDir == NULL)) { 
+        if (canUseAlternativeAdminDirUnderOSTree()) {
+            stateDir = "/etc/alternatives.admindir";
+         } else {
+             stateDir = "/var/lib/alternatives";
+         }
+
+        if ((dirExists(stateDir) == 0) && (mkdir(stateDir, 0755) == -1)) {
+            fprintf(stderr, _("creating admindir: %s\n"), strerror(errno));
+            exit(2);
+        }
+    }
+
     if (stat(stateDir, &sb) || !S_ISDIR(sb.st_mode) || access(stateDir, F_OK)) {
         fprintf(stderr, _("admindir %s invalid\n"), stateDir);
         exit(2);

chkconfig.spec

@@ -19,7 +19,7 @@ Provides: /sbin/chkconfig
 %description
 Chkconfig is a basic system utility.  It updates and queries runlevel
 information for system services.  Chkconfig manipulates the numerous
-symbolic links in /etc/rc.d, to relieve system administrators of some 
+symbolic links in /etc/rc.d, to relieve system administrators of some
 of the drudgery of manually editing the symbolic links.
 
 %package -n ntsysv
@@ -93,11 +93,12 @@ mkdir -p $RPM_BUILD_ROOT/etc/chkconfig.d
 %files -n alternatives
 %license COPYING
 %dir /etc/alternatives
+%ghost /etc/alternatives.admindir
+%ghost /var/lib/alternatives
 %{_sbindir}/update-alternatives
 %{_sbindir}/alternatives
 %{_mandir}/*/update-alternatives*
 %{_mandir}/*/alternatives*
-%dir /var/lib/alternatives
 
 %changelog
 * Fri Jun 21 2024 Jan Macku <[email protected]> - 1.28-1

po/chkconfig.pot

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2024-07-26 11:46+0200\n"
+"POT-Creation-Date: 2024-07-31 14:15+0200\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <[email protected]>\n"
@@ -562,22 +562,27 @@ msgstr ""
 msgid "failed to remove %s: %s\n"
 msgstr ""
 
-#: ../alternatives.c:1365
+#: ../alternatives.c:1303 ../alternatives.c:1473
+#, c-format
+msgid "admindir %s invalid\n"
+msgstr ""
+
+#: ../alternatives.c:1391
 #, c-format
 msgid "--family can't contain the symbol '@'\n"
 msgstr ""
 
-#: ../alternatives.c:1427
+#: ../alternatives.c:1455
 #, c-format
 msgid "altdir %s invalid\n"
 msgstr ""
 
-#: ../alternatives.c:1432
+#: ../alternatives.c:1467
 #, c-format
-msgid "admindir %s invalid\n"
+msgid "creating admindir: %s\n"
 msgstr ""
 
-#: ../alternatives.c:1442
+#: ../alternatives.c:1483
 #, c-format
 msgid "alternatives version %s\n"
 msgstr ""