From 97ca450966fb11273868a49cefa8d575bc34a13f Mon Sep 17 00:00:00 2001
From: Joachim Wiberg <troglobit@gmail.com>
Date: Mon, 27 Feb 2023 23:00:54 +0100
Subject: [PATCH] Add support for static services in /lib/finit/system/*.conf

Slowly migrating away from hard-coded services in plugins.  This way
it's possible for the user to both inspect and override as needed.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
---
 configure.ac |  5 +++++
 src/conf.c   | 25 +++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 14907fa2..6de02767 100644
--- a/configure.ac
+++ b/configure.ac
@@ -14,6 +14,7 @@ AC_CONFIG_FILES([Makefile
 	man/Makefile
 	plugins/Makefile
 	src/Makefile
+	system/Makefile
 	tmpfiles.d/Makefile
 	test/test.env test/Makefile
 	test/lib/Makefile test/src/Makefile])
@@ -289,6 +290,10 @@ AC_EXPAND_DIR(finit_tmpfiles, "$pkglibdir/tmpfiles.d")
 AC_SUBST(finit_tmpfiles)
 AC_DEFINE_UNQUOTED(FINIT_TMPFILES, "$finit_tmpfiles", [Finit tmpfiles.d/ .conf path])
 
+AC_EXPAND_DIR(system_path, "$pkglibdir/system")
+AC_SUBST(system_path)
+AC_DEFINE_UNQUOTED(FINIT_SYSPATH, "$system_path", [Static services, previously generated at runtime by plugins])
+
 AC_EXPAND_DIR(rescue_conf, "$pkglibdir/rescue.conf")
 AC_DEFINE_UNQUOTED(RESCUE_CONF, "$rescue_conf", [Finit rescue mode .conf])
 AC_EXPAND_DIR(sample_conf, "$pkglibdir/sample.conf")
diff --git a/src/conf.c b/src/conf.c
index a8ce00f4..7ed855f4 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -941,9 +941,17 @@ int conf_reload(void)
 			      rlim2str(i), lim2str(&global_rlimit[i]));
 	}
 
-	/* Next, read all *.conf in /etc/finit.d/ */
+	/*
+	 * Next, read all *.conf in /lib/finit/system and /etc/finit.d/
+	 * The system files were previously created at runtime by plugins
+	 * but are now regular files that can be overridden by files in
+	 * /etc/finit.d -- similar to how tmfiles.d(5) work.  E.g., add
+	 * an override .conf, or an ignore by symlinking to /dev/null
+	 */
 	snprintf(path, sizeof(path), "%s/*.conf", finit_rcsd);
 	glob(path, 0, NULL, &gl);
+	snprintf(path, sizeof(path), "%s/*.conf", FINIT_SYSPATH);
+	glob(path, GLOB_APPEND, NULL, &gl);
 	snprintf(path, sizeof(path), "%s/enabled/*.conf", finit_rcsd);
 	glob(path, GLOB_APPEND, NULL, &gl);
 
@@ -951,7 +959,20 @@ int conf_reload(void)
 		char *path = gl.gl_pathv[i];
 		char *rp = NULL;
 		struct stat st;
-		size_t len;
+		size_t j, len;
+
+		/* check for FINIT_SYSPATH overrides */
+		for (j = i + 1; j < gl.gl_pathc; j++) {
+			if (strncmp(path, FINIT_SYSPATH, strlen(FINIT_SYSPATH)))
+				continue;
+			if (strcmp(basename(path), basename(gl.gl_pathv[j])))
+				continue;
+			path = NULL; /* replacement later in list, skip this */
+			break;
+		}
+
+		if (!path)
+			continue; /* skip, override exists */
 
 		/* Check that it's an actual file ... beyond any symlinks */
 		if (lstat(path, &st)) {