From 2f8c48b6059b9d22ff40bc260bfb1939419b4e84 Mon Sep 17 00:00:00 2001
From: Anita Zhang <the.anitazha@gmail.com>
Date: Wed, 11 Dec 2019 21:15:42 -0800
Subject: [PATCH] core,journal: export user units' InvocationID and use as
 _SYSTEMD_INVOCATION_ID

Write a user unit's invocation ID to /run/user/<uid>/systemd/units/ similar
to how a system unit's invocation ID is written to /run/systemd/units/.

This lets the journal read and add a user unit's invocation ID to the
_SYSTEMD_INVOCATION_ID field of logs instead of the user manager's
invocation ID.

Fixes #12474
---
 src/core/manager.c             | 13 +++++++--
 src/core/unit.c                | 53 ++++++++++++++++++++++++++--------
 src/journal/journald-context.c | 18 +++++++++---
 3 files changed, 66 insertions(+), 18 deletions(-)

diff --git a/src/core/manager.c b/src/core/manager.c
index 13a6b49a8f2..171ff04631e 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -881,8 +881,17 @@ int manager_new(UnitFileScope scope, ManagerTestRunFlags test_run_flags, Manager
                         return r;
         }
 
-        if (MANAGER_IS_SYSTEM(m) && test_run_flags == 0) {
-                r = mkdir_label("/run/systemd/units", 0755);
+        if (test_run_flags == 0) {
+                if (MANAGER_IS_SYSTEM(m))
+                        r = mkdir_label("/run/systemd/units", 0755);
+                else {
+                        _cleanup_free_ char *units_path = NULL;
+                        r = xdg_user_runtime_dir(&units_path, "/systemd/units");
+                        if (r < 0)
+                                return r;
+                        r = mkdir_p_label(units_path, 0755);
+                }
+
                 if (r < 0 && r != -EEXIST)
                         return r;
         }
diff --git a/src/core/unit.c b/src/core/unit.c
index c406bb7ab29..03b4b57273a 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -5373,8 +5373,32 @@ void unit_remove_dependencies(Unit *u, UnitDependencyMask mask) {
         }
 }
 
+static int unit_get_invocation_path(Unit *u, char **ret) {
+        char *p;
+        int r;
+
+        assert(u);
+        assert(ret);
+
+        if (MANAGER_IS_SYSTEM(u->manager))
+                p = strjoin("/run/systemd/units/invocation:", u->id);
+        else {
+                _cleanup_free_ char *user_path = NULL;
+                r = xdg_user_runtime_dir(&user_path, "/systemd/units/invocation:");
+                if (r < 0)
+                        return r;
+                p = strjoin(user_path, u->id);
+        }
+
+        if (!p)
+                return -ENOMEM;
+
+        *ret = p;
+        return 0;
+}
+
 static int unit_export_invocation_id(Unit *u) {
-        const char *p;
+        _cleanup_free_ char *p = NULL;
         int r;
 
         assert(u);
@@ -5385,7 +5409,10 @@ static int unit_export_invocation_id(Unit *u) {
         if (sd_id128_is_null(u->invocation_id))
                 return 0;
 
-        p = strjoina("/run/systemd/units/invocation:", u->id);
+        r = unit_get_invocation_path(u, &p);
+        if (r < 0)
+                return log_unit_debug_errno(u, r, "Failed to get invocation path: %m");
+
         r = symlink_atomic(u->invocation_id_string, p);
         if (r < 0)
                 return log_unit_debug_errno(u, r, "Failed to create invocation ID symlink %s: %m", p);
@@ -5538,9 +5565,6 @@ void unit_export_state_files(Unit *u) {
         if (!u->id)
                 return;
 
-        if (!MANAGER_IS_SYSTEM(u->manager))
-                return;
-
         if (MANAGER_IS_TEST_RUN(u->manager))
                 return;
 
@@ -5559,6 +5583,9 @@ void unit_export_state_files(Unit *u) {
 
         (void) unit_export_invocation_id(u);
 
+        if (!MANAGER_IS_SYSTEM(u->manager))
+                return;
+
         c = unit_get_exec_context(u);
         if (c) {
                 (void) unit_export_log_level_max(u, c);
@@ -5576,18 +5603,20 @@ void unit_unlink_state_files(Unit *u) {
         if (!u->id)
                 return;
 
-        if (!MANAGER_IS_SYSTEM(u->manager))
-                return;
-
         /* Undoes the effect of unit_export_state() */
 
         if (u->exported_invocation_id) {
-                p = strjoina("/run/systemd/units/invocation:", u->id);
-                (void) unlink(p);
-
-                u->exported_invocation_id = false;
+                _cleanup_free_ char *invocation_path = NULL;
+                int r = unit_get_invocation_path(u, &invocation_path);
+                if (r >= 0) {
+                        (void) unlink(invocation_path);
+                        u->exported_invocation_id = false;
+                }
         }
 
+        if (!MANAGER_IS_SYSTEM(u->manager))
+                return;
+
         if (u->exported_log_level_max) {
                 p = strjoina("/run/systemd/units/log-level-max:", u->id);
                 (void) unlink(p);
diff --git a/src/journal/journald-context.c b/src/journal/journald-context.c
index 342ed062d46..cd4cfbee48c 100644
--- a/src/journal/journald-context.c
+++ b/src/journal/journald-context.c
@@ -325,19 +325,29 @@ static int client_context_read_invocation_id(
                 Server *s,
                 ClientContext *c) {
 
-        _cleanup_free_ char *value = NULL;
-        const char *p;
+        _cleanup_free_ char *p = NULL, *value = NULL;
         int r;
 
         assert(s);
         assert(c);
 
-        /* Read the invocation ID of a unit off a unit. PID 1 stores it in a per-unit symlink in /run/systemd/units/ */
+        /* Read the invocation ID of a unit off a unit.
+         * PID 1 stores it in a per-unit symlink in /run/systemd/units/
+         * User managers store it in a per-unit symlink under /run/user/<uid>/systemd/units/ */
 
         if (!c->unit)
                 return 0;
 
-        p = strjoina("/run/systemd/units/invocation:", c->unit);
+        if (c->user_unit) {
+                r = asprintf(&p, "/run/user/" UID_FMT "/systemd/units/invocation:%s", c->owner_uid, c->user_unit);
+                if (r < 0)
+                        return r;
+        } else {
+                p = strjoin("/run/systemd/units/invocation:", c->unit);
+                if (!p)
+                        return -ENOMEM;
+        }
+
         r = readlink_malloc(p, &value);
         if (r < 0)
                 return r;