From 0eebf94c0d6d53d2199163a4c81232591b65da3c Mon Sep 17 00:00:00 2001
From: "Anna (navi) Figueiredo Gomes" <navi@vlhl.dev>
Date: Fri, 19 Jul 2024 15:41:44 +0200
Subject: librc-depend.c: dynamically generate services for multiplexed
 services.

when generating back references, attempt to instantiate missing
services.

Signed-off-by: Anna (navi) Figueiredo Gomes <navi@vlhl.dev>
---
 src/librc/librc-depend.c | 66 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 53 insertions(+), 13 deletions(-)

(limited to 'src/librc')

diff --git a/src/librc/librc-depend.c b/src/librc/librc-depend.c
index cb38f190..4f72f2df 100644
--- a/src/librc/librc-depend.c
+++ b/src/librc/librc-depend.c
@@ -833,7 +833,7 @@ filter_sys(RC_DEPTREE *deptree, const char *sys)
 }
 
 static bool
-deptree_generate(RC_DEPTREE *deptree, RC_STRINGLIST **config)
+deptree_generate(const char *target, RC_DEPTREE *deptree, RC_STRINGLIST **config)
 {
 	FILE *fp;
 	RC_DEPTREE *providers;
@@ -854,10 +854,21 @@ deptree_generate(RC_DEPTREE *deptree, RC_STRINGLIST **config)
 	if (uname(&uts) == 0)
 		setenv("RC_UNAME", uts.sysname, 1);
 	/* Phase 1 - source all init scripts and print dependencies */
-	if (!(fp = popen(GENDEP, "r")))
+
+	if (target) {
+		char *cmd;
+		xasprintf(&cmd, GENDEP " %s", target);
+		fp = popen(cmd, "r");
+		free(cmd);
+	} else {
+		fp = popen(GENDEP, "r");
+	}
+
+	if (!fp)
 		return false;
 
-	*config = rc_stringlist_new();
+	if (config)
+		*config = rc_stringlist_new();
 
 	while ((size = getline(&line, &len, fp)) != -1) {
 		line[size - 1] = '\0';
@@ -895,7 +906,8 @@ deptree_generate(RC_DEPTREE *deptree, RC_STRINGLIST **config)
 				continue;
 
 			if (strcmp(type, "config") == 0) {
-				rc_stringlist_addu(*config, depend);
+				if (config)
+					rc_stringlist_addu(*config, depend);
 				continue;
 			}
 
@@ -928,9 +940,9 @@ deptree_generate(RC_DEPTREE *deptree, RC_STRINGLIST **config)
 			}
 			/* If we're after something, remove us from the before list */
 			if (strcmp(type, "iafter") == 0 ||
-			    strcmp(type, "ineed") == 0 ||
-			    strcmp(type, "iwant") == 0 ||
-			    strcmp(type, "iuse") == 0) {
+					strcmp(type, "ineed") == 0 ||
+					strcmp(type, "iwant") == 0 ||
+					strcmp(type, "iuse") == 0) {
 				if ((dt = get_deptype(depinfo, "ibefore")))
 					rc_stringlist_delete(dt->services, depend);
 			}
@@ -964,15 +976,42 @@ deptree_generate(RC_DEPTREE *deptree, RC_STRINGLIST **config)
 	return true;
 }
 
+static RC_DEPINFO *
+make_dylink_depinfo(RC_DEPTREE *deptree, const char *service)
+{
+	RC_DEPINFO *di = NULL;
+	char *target_file = NULL;
+	char *base = rc_service_base(service);
+	if (!base)
+		return NULL;
+	target_file = rc_service_dylink(base, service);
+	if (!target_file)
+		goto out;
+	/* TODO: integrate configuration checking for dynamic services */
+	if (!deptree_generate(target_file, deptree, NULL))
+		goto out;
+
+	di = get_depinfo(deptree, service);
+
+out:
+	free(base);
+	free(target_file);
+	return di;
+}
+
 /* This is a 7 phase operation
    Phase 1 is a shell script which loads each init script and config in turn
-   and echos their dependency info to stdout
-   Phase 2 takes that and populates a depinfo object with that data
+   and echos their dependency info to stdout and populates a depinfo object
+   with that data
+   Phase 2 filters services for system compatibility (i.e. keyword -container)
    Phase 3 adds any provided services to the depinfo object
-   Phase 4 scans that depinfo object and puts in backlinks
+
+   Phase 4 scans that depinfo object and puts in backlinks, and dynamically
+   links services on the <base>.<service> format that are missing.
    Phase 5 removes broken before dependencies
    Phase 6 looks for duplicate services indicating a real and virtual service
    with the same names
+
    Phase 7 saves the depinfo object to disk
    */
 bool
@@ -992,12 +1031,13 @@ rc_deptree_update(void)
 
 	deptree = xmalloc(sizeof(*deptree));
 	TAILQ_INIT(deptree);
-	if (!deptree_generate(deptree, &config)) {
+	/* Phases 1..3 - generate intial deptree */
+	if (!deptree_generate(NULL, deptree, &config)) {
 		free(deptree);
 		return false;
 	}
 
-	/* Phase 4 - backreference our depends */
+	/* Phase 4 - backreference our depends and dylink services */
 	TAILQ_FOREACH(depinfo, deptree, entries) {
 		for (size_t i = 0; deppairs[i].depend; i++) {
 			deptype = get_deptype(depinfo, deppairs[i].depend);
@@ -1005,7 +1045,7 @@ rc_deptree_update(void)
 				continue;
 			TAILQ_FOREACH(s, deptype->services, entries) {
 				di = get_depinfo(deptree, s->value);
-				if (!di) {
+				if (!di && !(di = make_dylink_depinfo(deptree, s->value))) {
 					if (strcmp(deptype->type, "ineed") == 0) {
 						fprintf(stderr, "Service '%s' needs non existent service '%s'\n",
 							 depinfo->service, s->value);
-- 
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