Adding user service support fails: No such file or directory

[brandon-arnold]

Hi all. I'm on Artix Linux, but the documentation for OpenRC in Gentoo's Wiki has been pretty solid so far.

I'm trying to get the experimental user services going. Generally I can get it going if I copy-paste /etc/init.d/user to /etc/init.d/user_brandon, and run sudo rc-update add user_brandon manually. Notice the underscore in my filename.

This filename isn't kosher with the documentation and doesn't start as-is on boot. I'm pretty sure I could just edit the script to make it work, but I want to do it the way the documentation (and OpenRC) is designed.

The recommended approach is making a symlink from, e.g., /etc/init.d/user.brandon -> /etc/init.d/user, with a dot . in the filename. But:

sudo ln -s /etc/init.d/user /etc/init.d/user.brandon
sudo rc-update add user.brandon
 * rc-update: failed to add service `user.brandon' to runlevel `default': No such file or directory

Can anyone say why?

[navi-desu]

i see what is happening, user.brandon is started via pam

there's a check against adding dynamically multiplexed services to a runlevel, which would be fine here since the service exists in /etc as well

but the service-to-path resolution code checks for started services first, and thus it's getting the path to the service in /run, not good

i'll come up with a patch... for now as a workaround, you may manually symlink ln -s /etc/init.d/user.brandon /etc/runlevels/default

[brandon-arnold]

i'll come up with a patch... for now as a workaround, you may manually symlink ln -s /etc/init.d/user.brandon /etc/runlevels/default

Works great, for now, and glad to hear of a patch. Thank you, @navi-desu

[martinetd]

As discussed in #895 I've had a quick look as well and could reproduce, but I'm not sure I can come up with something better than what @navi-desu called "not pretty" -- basically, add a private variant of rc_service_resolve that takes a flag in argument to ignore running services:

diff --git a/src/librc/librc.c b/src/librc/librc.c
index 70016324518b..a7091431686c 100644
--- a/src/librc/librc.c
+++ b/src/librc/librc.c
@@ -731,9 +731,8 @@ safe_readlink(int targetfd, const char *path, char **buf, size_t bufsiz)
 	}
 }
 
-/* Resolve a service name to its full path */
-char *
-rc_service_resolve(const char *service)
+static char *
+_rc_service_resolve(const char *service, bool check_running)
 {
 	char *buffer;
 	struct stat buf;
@@ -744,13 +743,15 @@ rc_service_resolve(const char *service)
 	if (service[0] == '/')
 		return xstrdup(service);
 
-	/* First check started services */
-	if (fstatat(rc_dirfd(RC_DIR_STARTED), service, &buf, AT_SYMLINK_NOFOLLOW) == 0 && S_ISLNK(buf.st_mode))
-		if (safe_readlink(rc_dirfd(RC_DIR_STARTED), service, &buffer, buf.st_size + 1) >= 0)
-			return buffer;
-	if (fstatat(rc_dirfd(RC_DIR_INACTIVE), service, &buf, AT_SYMLINK_NOFOLLOW) == 0 && S_ISLNK(buf.st_mode))
-		if (safe_readlink(rc_dirfd(RC_DIR_INACTIVE), service, &buffer, buf.st_size + 1) >= 0)
-			return buffer;
+	if (check_running) {
+		/* First check started services */
+		if (fstatat(rc_dirfd(RC_DIR_STARTED), service, &buf, AT_SYMLINK_NOFOLLOW) == 0 && S_ISLNK(buf.st_mode))
+			if (safe_readlink(rc_dirfd(RC_DIR_STARTED), service, &buffer, buf.st_size + 1) >= 0)
+				return buffer;
+		if (fstatat(rc_dirfd(RC_DIR_INACTIVE), service, &buf, AT_SYMLINK_NOFOLLOW) == 0 && S_ISLNK(buf.st_mode))
+			if (safe_readlink(rc_dirfd(RC_DIR_INACTIVE), service, &buffer, buf.st_size + 1) >= 0)
+				return buffer;
+	}
 
 	for (const char * const *dirs = rc_scriptdirs(); *dirs; dirs++) {
 		char *file = NULL;
@@ -763,6 +764,13 @@ rc_service_resolve(const char *service)
 	return NULL;
 }
 
+/* Resolve a service name to its full path */
+char *
+rc_service_resolve(const char *service)
+{
+	return _rc_service_resolve(service, true);
+}
+
 bool
 rc_service_exists(const char *service)
 {
@@ -1190,7 +1198,7 @@ rc_service_add(const char *runlevel, const char *service)
 		return false;
 	}
 
-	i = init = rc_service_resolve(service);
+	i = init = _rc_service_resolve(service, false);
 
 	/* We need to ensure that only things in /etc/init.d are added
 	* to the boot runlevel -- not applicable for user services. */
@@ -1212,7 +1220,7 @@ rc_service_add(const char *runlevel, const char *service)
 	}
 
 	/* We shouldn't add any temporary script to a runlevel */
-	if (strncmp(i, rc_svcdir(), strlen(rc_svcdir())) == 0) {
+	if (!i || strncmp(i, rc_svcdir(), strlen(rc_svcdir())) == 0) {
 		errno = ENOENT;
 		retval = false;
 		goto out;

(the last check for i because _rc_service_resolve() can now return NULL when it found a running service previously)

I guess it's not too horrible, what do you think?

(On the other hand, I'm not sure that warrants a backport to the stable branch? Well, I guess it'd help if we want to promote user services)

[navi-desu]

that's the same solution i wasn't a big fan of ~w~

i'll release .6 later today without a fix for this yet, and probably fix it in the next minor release

[martinetd]

that's the same solution i wasn't a big fan of w

Figures :)

i'll release .6 later today without a fix for this yet, and probably fix it in the next minor release

Thank you, I've seen the release! I've opened a MR for alpine master and will backport it to 3.22 after it gets merged (likely tomorrow-ish)