From 6c9c51e5e2fcc2bf91d739f6d31ae475e6772af6 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sun, 23 Sep 2018 16:17:03 +0900
Subject: [PATCH] fs-util: make symlink_idempotent() optionally create relative
 link

---
 src/basic/fs-util.c        | 17 ++++++++++++++++-
 src/basic/fs-util.h        |  2 +-
 src/core/execute.c         | 14 ++------------
 src/core/socket.c          |  4 ++--
 src/nspawn/nspawn-cgroup.c |  4 ++--
 5 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index 09fcc32..1fa76bd 100644
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -346,12 +346,27 @@ int touch(const char *path) {
         return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
 }
 
-int symlink_idempotent(const char *from, const char *to) {
+int symlink_idempotent(const char *from, const char *to, bool make_relative) {
+        _cleanup_free_ char *relpath = NULL;
         int r;
 
         assert(from);
         assert(to);
 
+        if (make_relative) {
+                _cleanup_free_ char *parent = NULL;
+
+                parent = dirname_malloc(to);
+                if (!parent)
+                        return -ENOMEM;
+
+                r = path_make_relative(parent, from, &relpath);
+                if (r < 0)
+                        return r;
+
+                from = relpath;
+        }
+
         if (symlink(from, to) < 0) {
                 _cleanup_free_ char *p = NULL;
 
diff --git a/src/basic/fs-util.h b/src/basic/fs-util.h
index 4b65625..bc753d5 100644
--- a/src/basic/fs-util.h
+++ b/src/basic/fs-util.h
@@ -37,7 +37,7 @@ int fd_warn_permissions(const char *path, int fd);
 int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode);
 int touch(const char *path);
 
-int symlink_idempotent(const char *from, const char *to);
+int symlink_idempotent(const char *from, const char *to, bool make_relative);
 
 int symlink_atomic(const char *from, const char *to);
 int mknod_atomic(const char *path, mode_t mode, dev_t dev);
diff --git a/src/core/execute.c b/src/core/execute.c
index 35dd389..77e3ce8 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -2027,7 +2027,7 @@ static int setup_exec_directory(
 
                 if (context->dynamic_user &&
                     !IN_SET(type, EXEC_DIRECTORY_RUNTIME, EXEC_DIRECTORY_CONFIGURATION)) {
-                        _cleanup_free_ char *private_root = NULL, *relative = NULL, *parent = NULL;
+                        _cleanup_free_ char *private_root = NULL;
 
                         /* So, here's one extra complication when dealing with DynamicUser=1 units. In that case we
                          * want to avoid leaving a directory around fully accessible that is owned by a dynamic user
@@ -2092,18 +2092,8 @@ static int setup_exec_directory(
                                         goto fail;
                         }
 
-                        parent = dirname_malloc(p);
-                        if (!parent) {
-                                r = -ENOMEM;
-                                goto fail;
-                        }
-
-                        r = path_make_relative(parent, pp, &relative);
-                        if (r < 0)
-                                goto fail;
-
                         /* And link it up from the original place */
-                        r = symlink_idempotent(relative, p);
+                        r = symlink_idempotent(pp, p, true);
                         if (r < 0)
                                 goto fail;
 
diff --git a/src/core/socket.c b/src/core/socket.c
index 8775bc8..aac80f3 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1313,7 +1313,7 @@ static int socket_symlink(Socket *s) {
         STRV_FOREACH(i, s->symlinks) {
                 (void) mkdir_parents_label(*i, s->directory_mode);
 
-                r = symlink_idempotent(p, *i);
+                r = symlink_idempotent(p, *i, false);
 
                 if (r == -EEXIST && s->remove_on_stop) {
                         /* If there's already something where we want to create the symlink, and the destructive
@@ -1321,7 +1321,7 @@ static int socket_symlink(Socket *s) {
                          * again. */
 
                         if (unlink(*i) >= 0)
-                                r = symlink_idempotent(p, *i);
+                                r = symlink_idempotent(p, *i, false);
                 }
 
                 if (r < 0)
diff --git a/src/nspawn/nspawn-cgroup.c b/src/nspawn/nspawn-cgroup.c
index 4a3cd29..f7ec077 100644
--- a/src/nspawn/nspawn-cgroup.c
+++ b/src/nspawn/nspawn-cgroup.c
@@ -373,7 +373,7 @@ static int mount_legacy_cgns_supported(
                         if (!target)
                                 return log_oom();
 
-                        r = symlink_idempotent(controller, target);
+                        r = symlink_idempotent(controller, target, false);
                         if (r == -EINVAL)
                                 return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m");
                         if (r < 0)
@@ -482,7 +482,7 @@ static int mount_legacy_cgns_unsupported(
                         if (r < 0)
                                 return r;
 
-                        r = symlink_idempotent(combined, target);
+                        r = symlink_idempotent(combined, target, false);
                         if (r == -EINVAL)
                                 return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m");
                         if (r < 0)
-- 
2.7.4