From e2d699c92944c6251f9de161c9e3ae93d915c4e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Thu, 17 Mar 2022 15:50:16 +0100
Subject: [PATCH] shared/install: split UNIT_FILE_SYMLINK into two states

The two states are distinguished, but are treated everywhere identically,
so there is no difference in behaviour except for slighlty different log
output.

(cherry picked from commit 48ed75adabef3427767038fa155e55b3b0d48f35)

Related: #2082131
---
 src/basic/unit-file.c |  6 ++++--
 src/shared/install.c  | 14 +++++++++-----
 src/shared/install.h  |  3 ++-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/basic/unit-file.c b/src/basic/unit-file.c
index 2474648ceb..7c1ae515e1 100644
--- a/src/basic/unit-file.c
+++ b/src/basic/unit-file.c
@@ -282,7 +282,9 @@ int unit_file_resolve_symlink(
          *
          * If resolve_destination_target is true, an absolute path will be returned.
          * If not, an absolute path is returned for linked unit files, and a relative
-         * path otherwise. */
+         * path otherwise.
+         *
+         * Returns an error, false if this is an alias, true if it's a linked unit file. */
 
         assert(filename);
         assert(ret_destination);
@@ -364,7 +366,7 @@ int unit_file_resolve_symlink(
         }
 
         *ret_destination = TAKE_PTR(dst);
-        return 0;
+        return !tail;  /* true if linked unit file */
 }
 
 int unit_file_build_name_map(
diff --git a/src/shared/install.c b/src/shared/install.c
index f911d527df..b33f7d4bc1 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -93,8 +93,9 @@ void unit_file_presets_freep(UnitFilePresets *p) {
 
 static const char *const unit_file_type_table[_UNIT_FILE_TYPE_MAX] = {
         [UNIT_FILE_TYPE_REGULAR] = "regular",
-        [UNIT_FILE_TYPE_SYMLINK] = "symlink",
-        [UNIT_FILE_TYPE_MASKED] = "masked",
+        [UNIT_FILE_TYPE_LINKED]  = "linked",
+        [UNIT_FILE_TYPE_ALIAS]   = "alias",
+        [UNIT_FILE_TYPE_MASKED]  = "masked",
 };
 
 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(unit_file_type, UnitFileType);
@@ -1404,14 +1405,17 @@ static int unit_file_load_or_readlink(
                                       true, &info->symlink_target);
         if (r < 0)
                 return r;
+        bool outside_search_path = r > 0;
 
         r = null_or_empty_path_with_root(info->symlink_target, lp->root_dir);
         if (r < 0 && r != -ENOENT)
                 return log_debug_errno(r, "Failed to stat %s: %m", info->symlink_target);
         if (r > 0)
                 info->type = UNIT_FILE_TYPE_MASKED;
+        else if (outside_search_path)
+                info->type = UNIT_FILE_TYPE_LINKED;
         else
-                info->type = UNIT_FILE_TYPE_SYMLINK;
+                info->type = UNIT_FILE_TYPE_ALIAS;
 
         return 0;
 }
@@ -1550,7 +1554,7 @@ static int install_info_follow(
         assert(ctx);
         assert(info);
 
-        if (info->type != UNIT_FILE_TYPE_SYMLINK)
+        if (!IN_SET(info->type, UNIT_FILE_TYPE_ALIAS, UNIT_FILE_TYPE_LINKED))
                 return -EINVAL;
         if (!info->symlink_target)
                 return -EINVAL;
@@ -1591,7 +1595,7 @@ static int install_info_traverse(
                 return r;
 
         i = start;
-        while (i->type == UNIT_FILE_TYPE_SYMLINK) {
+        while (IN_SET(i->type, UNIT_FILE_TYPE_ALIAS, UNIT_FILE_TYPE_LINKED)) {
                 /* Follow the symlink */
 
                 if (++k > UNIT_FILE_FOLLOW_SYMLINK_MAX)
diff --git a/src/shared/install.h b/src/shared/install.h
index dba6987406..95427537f2 100644
--- a/src/shared/install.h
+++ b/src/shared/install.h
@@ -70,7 +70,8 @@ struct UnitFileList {
 
 enum UnitFileType {
         UNIT_FILE_TYPE_REGULAR,
-        UNIT_FILE_TYPE_SYMLINK,
+        UNIT_FILE_TYPE_LINKED,
+        UNIT_FILE_TYPE_ALIAS,
         UNIT_FILE_TYPE_MASKED,
         _UNIT_FILE_TYPE_MAX,
         _UNIT_FILE_TYPE_INVALID = -EINVAL,