Merge pull request #23309 from DaanDeMeyer/log-context

basic: Add log context

22 files changed, 528 insertions, 96 deletions

diff --git a/docs/ENVIRONMENT.md b/docs/ENVIRONMENT.md
index ef0141e1a6..30ef1e7e42 100644
--- a/docs/ENVIRONMENT.md
+++ b/docs/ENVIRONMENT.md
@@ -114,6 +114,9 @@ All tools:
   for example in `systemd-nspawn`, will be logged to the audit log, if the
   kernel supports this.
 
+* `$SYSTEMD_ENABLE_LOG_CONTEXT` — if set, extra fields will always be logged to
+the journal instead of only when logging in debug mode.
+
 `systemctl`:
 
 * `$SYSTEMCTL_FORCE_BUS=1` — if set, do not connect to PID 1's private D-Bus
diff --git a/src/basic/list.h b/src/basic/list.h
index ca30039690..ffc8bd8304 100644
--- a/src/basic/list.h
+++ b/src/basic/list.h
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "macro.h"
-
 /* The head of the linked list. Use this in the structure that shall
  * contain the head of the linked list */
 #define LIST_HEAD(t,name)                                               \
@@ -28,26 +26,27 @@
 
 /* Prepend an item to the list */
 #define LIST_PREPEND(name,head,item)                                    \
-        do {                                                            \
+        ({                                                              \
                 typeof(*(head)) **_head = &(head), *_item = (item);     \
                 assert(_item);                                          \
                 if ((_item->name##_next = *_head))                      \
                         _item->name##_next->name##_prev = _item;        \
                 _item->name##_prev = NULL;                              \
                 *_head = _item;                                         \
-        } while (false)
+                _item;                                                  \
+        })
 
 /* Append an item to the list */
 #define LIST_APPEND(name,head,item)                                     \
-        do {                                                            \
+        ({                                                              \
                 typeof(*(head)) **_hhead = &(head), *_tail;             \
-                LIST_FIND_TAIL(name, *_hhead, _tail);                   \
+                _tail = LIST_FIND_TAIL(name, *_hhead);                  \
                 LIST_INSERT_AFTER(name, *_hhead, _tail, item);          \
-        } while (false)
+        })
 
 /* Remove an item from the list */
 #define LIST_REMOVE(name,head,item)                                     \
-        do {                                                            \
+        ({                                                            \
                 typeof(*(head)) **_head = &(head), *_item = (item);     \
                 assert(_item);                                          \
                 if (_item->name##_next)                                 \
@@ -59,37 +58,30 @@
                         *_head = _item->name##_next;                    \
                 }                                                       \
                 _item->name##_next = _item->name##_prev = NULL;         \
-        } while (false)
+                _item;                                                  \
+        })
 
 /* Find the head of the list */
-#define LIST_FIND_HEAD(name,item,head)                                  \
-        do {                                                            \
+#define LIST_FIND_HEAD(name,item)                                       \
+        ({                                                              \
                 typeof(*(item)) *_item = (item);                        \
-                if (!_item)                                             \
-                        (head) = NULL;                                  \
-                else {                                                  \
-                        while (_item->name##_prev)                      \
-                                _item = _item->name##_prev;             \
-                        (head) = _item;                                 \
-                }                                                       \
-        } while (false)
+                while (_item && _item->name##_prev)                     \
+                        _item = _item->name##_prev;                     \
+                _item;                                                  \
+        })
 
 /* Find the tail of the list */
-#define LIST_FIND_TAIL(name,item,tail)                                  \
-        do {                                                            \
+#define LIST_FIND_TAIL(name,item)                                       \
+        ({                                                              \
                 typeof(*(item)) *_item = (item);                        \
-                if (!_item)                                             \
-                        (tail) = NULL;                                  \
-                else {                                                  \
-                        while (_item->name##_next)                      \
-                                _item = _item->name##_next;             \
-                        (tail) = _item;                                 \
-                }                                                       \
-        } while (false)
+                while (_item && _item->name##_next)                     \
+                        _item = _item->name##_next;                     \
+                _item;                                                  \
+        })
 
 /* Insert an item after another one (a = where, b = what) */
 #define LIST_INSERT_AFTER(name,head,a,b)                                \
-        do {                                                            \
+        ({                                                              \
                 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
                 assert(_b);                                             \
                 if (!_a) {                                              \
@@ -103,11 +95,12 @@
                         _b->name##_prev = _a;                           \
                         _a->name##_next = _b;                           \
                 }                                                       \
-        } while (false)
+                _b;                                                     \
+        })
 
 /* Insert an item before another one (a = where, b = what) */
 #define LIST_INSERT_BEFORE(name,head,a,b)                               \
-        do {                                                            \
+        ({                                                              \
                 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
                 assert(_b);                                             \
                 if (!_a) {                                              \
@@ -131,7 +124,8 @@
                         _b->name##_next = _a;                           \
                         _a->name##_prev = _b;                           \
                 }                                                       \
-        } while (false)
+                _b;                                                     \
+        })
 
 #define LIST_JUST_US(name,item)                                         \
         (!(item)->name##_prev && !(item)->name##_next)
@@ -172,18 +166,19 @@
 
 /* Join two lists tail to head: a->b, c->d to a->b->c->d and de-initialise second list */
 #define LIST_JOIN(name,a,b)                                             \
-        do {                                                            \
+        ({                                                              \
                 assert(b);                                              \
                 if (!(a))                                               \
                         (a) = (b);                                      \
                 else {                                                  \
                         typeof(*(a)) *_head = (b), *_tail;              \
-                        LIST_FIND_TAIL(name, (a), _tail);               \
+                        _tail = LIST_FIND_TAIL(name, (a));              \
                         _tail->name##_next = _head;                     \
                         _head->name##_prev = _tail;                     \
                 }                                                       \
                 (b) = NULL;                                             \
-        } while (false)
+                a;                                                      \
+        })
 
 #define LIST_POP(name, a)                                               \
         ({                                                              \
@@ -193,3 +188,7 @@
                         LIST_REMOVE(name, *_a, _p);                     \
                 _p;                                                     \
         })
+
+/* Now include "macro.h", because we want our definition of assert() which the macros above use. We include
+ * it down here instead of up top, since macro.h pulls in log.h which in turn needs our own definitions. */
+#include "macro.h"
diff --git a/src/basic/log.c b/src/basic/log.c
index 282130345f..fc5793139e 100644
--- a/src/basic/log.c
+++ b/src/basic/log.c
@@ -17,6 +17,7 @@
 
 #include "alloc-util.h"
 #include "argv-util.h"
+#include "env-util.h"
 #include "errno-util.h"
 #include "fd-util.h"
 #include "format-util.h"
@@ -33,12 +34,14 @@
 #include "stdio-util.h"
 #include "string-table.h"
 #include "string-util.h"
+#include "strv.h"
 #include "syslog-util.h"
 #include "terminal-util.h"
 #include "time-util.h"
 #include "utf8.h"
 
 #define SNDBUF_SIZE (8*1024*1024)
+#define IOVEC_MAX 128U
 
 static log_syntax_callback_t log_syntax_callback = NULL;
 static void *log_syntax_callback_userdata = NULL;
@@ -68,6 +71,17 @@ static bool prohibit_ipc = false;
  * use here. */
 static char *log_abort_msg = NULL;
 
+typedef struct LogContext {
+        /* Depending on which destructor is used (log_context_free() or log_context_detach()) the memory
+         * referenced by this is freed or not */
+        char **fields;
+        bool owned;
+        LIST_FIELDS(struct LogContext, ll);
+} LogContext;
+
+static thread_local LIST_HEAD(LogContext, _log_context) = NULL;
+static thread_local size_t _log_context_num_fields = 0;
+
 #if LOG_MESSAGE_VERIFICATION || defined(__COVERITY__)
 bool _log_message_dummy = false; /* Always false */
 #endif
@@ -589,6 +603,20 @@ static int log_do_header(
         return 0;
 }
 
+static void log_do_context(struct iovec *iovec, size_t iovec_len, size_t *n) {
+        assert(iovec);
+        assert(n);
+
+        LIST_FOREACH(ll, c, _log_context)
+                STRV_FOREACH(s, c->fields) {
+                        if (*n + 2 >= iovec_len)
+                                return;
+
+                        iovec[(*n)++] = IOVEC_MAKE_STRING(*s);
+                        iovec[(*n)++] = IOVEC_MAKE_STRING("\n");
+                }
+}
+
 static int write_to_journal(
                 int level,
                 int error,
@@ -602,21 +630,27 @@ static int write_to_journal(
                 const char *buffer) {
 
         char header[LINE_MAX];
+        size_t n = 0, iovec_len;
+        struct iovec *iovec;
 
         if (journal_fd < 0)
                 return 0;
 
+        iovec_len = MIN(4 + _log_context_num_fields * 2, IOVEC_MAX);
+        iovec = newa(struct iovec, iovec_len);
+
         log_do_header(header, sizeof(header), level, error, file, line, func, object_field, object, extra_field, extra);
 
-        struct iovec iovec[4] = {
-                IOVEC_MAKE_STRING(header),
-                IOVEC_MAKE_STRING("MESSAGE="),
-                IOVEC_MAKE_STRING(buffer),
-                IOVEC_MAKE_STRING("\n"),
-        };
+        iovec[n++] = IOVEC_MAKE_STRING(header);
+        iovec[n++] = IOVEC_MAKE_STRING("MESSAGE=");
+        iovec[n++] = IOVEC_MAKE_STRING(buffer);
+        iovec[n++] = IOVEC_MAKE_STRING("\n");
+
+        log_do_context(iovec, iovec_len, &n);
+
         const struct msghdr msghdr = {
                 .msg_iov = iovec,
-                .msg_iovlen = ELEMENTSOF(iovec),
+                .msg_iovlen = n,
         };
 
         if (sendmsg(journal_fd, &msghdr, MSG_NOSIGNAL) < 0)
@@ -948,21 +982,27 @@ int log_struct_internal(
 
                 if (journal_fd >= 0) {
                         char header[LINE_MAX];
-                        struct iovec iovec[17];
-                        size_t n = 0;
+                        struct iovec *iovec;
+                        size_t n = 0, m, iovec_len;
                         int r;
                         bool fallback = false;
 
+                        iovec_len = MIN(17 + _log_context_num_fields * 2, IOVEC_MAX);
+                        iovec = newa(struct iovec, iovec_len);
+
                         /* If the journal is available do structured logging.
                          * Do not report the errno if it is synthetic. */
                         log_do_header(header, sizeof(header), level, error, file, line, func, NULL, NULL, NULL, NULL);
                         iovec[n++] = IOVEC_MAKE_STRING(header);
 
                         va_start(ap, format);
-                        r = log_format_iovec(iovec, ELEMENTSOF(iovec), &n, true, error, format, ap);
+                        r = log_format_iovec(iovec, iovec_len, &n, true, error, format, ap);
+                        m = n;
                         if (r < 0)
                                 fallback = true;
                         else {
+                                log_do_context(iovec, iovec_len, &n);
+
                                 const struct msghdr msghdr = {
                                         .msg_iov = iovec,
                                         .msg_iovlen = n,
@@ -972,7 +1012,7 @@ int log_struct_internal(
                         }
 
                         va_end(ap);
-                        for (size_t i = 1; i < n; i += 2)
+                        for (size_t i = 1; i < m; i += 2)
                                 free(iovec[i].iov_base);
 
                         if (!fallback) {
@@ -1041,18 +1081,25 @@ int log_struct_iovec_internal(
             journal_fd >= 0) {
 
                 char header[LINE_MAX];
+                struct iovec *iovec;
+                size_t n = 0, iovec_len;
+
+                iovec_len = MIN(1 + n_input_iovec * 2 + _log_context_num_fields * 2, IOVEC_MAX);
+                iovec = newa(struct iovec, iovec_len);
+
                 log_do_header(header, sizeof(header), level, error, file, line, func, NULL, NULL, NULL, NULL);
 
-                struct iovec iovec[1 + n_input_iovec*2];
-                iovec[0] = IOVEC_MAKE_STRING(header);
+                iovec[n++] = IOVEC_MAKE_STRING(header);
                 for (size_t i = 0; i < n_input_iovec; i++) {
-                        iovec[1+i*2] = input_iovec[i];
-                        iovec[1+i*2+1] = IOVEC_MAKE_STRING("\n");
+                        iovec[n++] = input_iovec[i];
+                        iovec[n++] = IOVEC_MAKE_STRING("\n");
                 }
 
+                log_do_context(iovec, iovec_len, &n);
+
                 const struct msghdr msghdr = {
                         .msg_iov = iovec,
-                        .msg_iovlen = 1 + n_input_iovec*2,
+                        .msg_iovlen = n,
                 };
 
                 if (sendmsg(journal_fd, &msghdr, MSG_NOSIGNAL) >= 0)
@@ -1477,3 +1524,88 @@ void log_setup(void) {
         if (log_on_console() && show_color < 0)
                 log_show_color(true);
 }
+
+static int saved_log_context_enabled = -1;
+
+bool log_context_enabled(void) {
+        int r;
+
+        if (log_get_max_level() == LOG_DEBUG)
+                return true;
+
+        if (saved_log_context_enabled >= 0)
+                return saved_log_context_enabled;
+
+        r = getenv_bool_secure("SYSTEMD_ENABLE_LOG_CONTEXT");
+        if (r < 0 && r != -ENXIO)
+                log_debug_errno(r, "Failed to parse $SYSTEMD_ENABLE_LOG_CONTEXT, ignoring: %m");
+
+        saved_log_context_enabled = r > 0;
+
+        return saved_log_context_enabled;
+}
+
+LogContext* log_context_attach(LogContext *c) {
+        assert(c);
+
+        _log_context_num_fields += strv_length(c->fields);
+
+        return LIST_PREPEND(ll, _log_context, c);
+}
+
+LogContext* log_context_detach(LogContext *c) {
+        if (!c)
+                return NULL;
+
+        assert(_log_context_num_fields >= strv_length(c->fields));
+        _log_context_num_fields -= strv_length(c->fields);
+
+        LIST_REMOVE(ll, _log_context, c);
+        return NULL;
+}
+
+LogContext* log_context_new(char **fields, bool owned) {
+        LogContext *c = new(LogContext, 1);
+        if (!c)
+                return NULL;
+
+        *c = (LogContext) {
+                .fields = fields,
+                .owned = owned,
+        };
+
+        return log_context_attach(c);
+}
+
+LogContext* log_context_free(LogContext *c) {
+        if (!c)
+                return NULL;
+
+        log_context_detach(c);
+
+        if (c->owned)
+                strv_free(c->fields);
+
+        return mfree(c);
+}
+
+LogContext* log_context_new_consume(char **fields) {
+        LogContext *c = log_context_new(fields, /*owned=*/ true);
+        if (!c)
+                strv_free(fields);
+
+        return c;
+}
+
+size_t log_context_num_contexts(void) {
+        size_t n = 0;
+
+        LIST_FOREACH(ll, c, _log_context)
+                n++;
+
+        return n;
+}
+
+size_t log_context_num_fields(void) {
+        return _log_context_num_fields;
+}
diff --git a/src/basic/log.h b/src/basic/log.h
index 2b1ac5f8c6..fcb8fcfb69 100644
--- a/src/basic/log.h
+++ b/src/basic/log.h
@@ -7,8 +7,10 @@
 #include <string.h>
 #include <syslog.h>
 
+#include "list.h"
 #include "macro.h"
 #include "ratelimit.h"
+#include "stdio-util.h"
 
 /* Some structures we reference but don't want to pull in headers for */
 struct iovec;
@@ -420,3 +422,83 @@ typedef struct LogRateLimit {
 #define log_ratelimit_warning_errno(error, ...)   log_ratelimit_full_errno(LOG_WARNING, error, __VA_ARGS__)
 #define log_ratelimit_error_errno(error, ...)     log_ratelimit_full_errno(LOG_ERR,     error, __VA_ARGS__)
 #define log_ratelimit_emergency_errno(error, ...) log_ratelimit_full_errno(log_emergency_level(), error, __VA_ARGS__)
+
+/*
+ * The log context allows attaching extra metadata to log messages written to the journal via log.h. We keep
+ * track of a thread local log context onto which we can push extra metadata fields that should be logged.
+ *
+ * LOG_CONTEXT_PUSH() will add the provided field to the log context and will remove it again when the
+ * current block ends. LOG_CONTEXT_PUSH_STRV() will do the same but for all fields in the given strv.
+ * LOG_CONTEXT_PUSHF() is like LOG_CONTEXT_PUSH() but takes a format string and arguments.
+ *
+ * Using the macros is as simple as putting them anywhere inside a block to add a field to all following log
+ * messages logged from inside that block.
+ *
+ * void myfunction(...) {
+ *         ...
+ *
+ *         LOG_CONTEXT_PUSHF("MYMETADATA=%s", "abc");
+ *
+ *         // Every journal message logged will now have the MYMETADATA=abc
+ *         // field included.
+ * }
+ *
+ * One special case to note is async code, where we use callbacks that are invoked to continue processing
+ * when some event occurs. For async code, there's usually an associated "userdata" struct containing all the
+ * information associated with the async operation. In this "userdata" struct, we can store a log context
+ * allocated with log_context_new() and freed with log_context_free(). We can then add and remove fields to
+ * the `fields` member of the log context object and all those fields will be logged along with each log
+ * message.
+ */
+
+typedef struct LogContext LogContext;
+
+bool log_context_enabled(void);
+
+LogContext* log_context_attach(LogContext *c);
+LogContext* log_context_detach(LogContext *c);
+
+LogContext* log_context_new(char **fields, bool owned);
+LogContext* log_context_free(LogContext *c);
+
+/* Same as log_context_new(), but frees the given fields strv on failure. */
+LogContext* log_context_new_consume(char **fields);
+
+/* Returns the number of attached log context objects. */
+size_t log_context_num_contexts(void);
+/* Returns the number of fields in all attached log contexts. */
+size_t log_context_num_fields(void);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(LogContext*, log_context_detach);
+DEFINE_TRIVIAL_CLEANUP_FUNC(LogContext*, log_context_free);
+
+#define LOG_CONTEXT_PUSH(...) \
+        LOG_CONTEXT_PUSH_STRV(STRV_MAKE(__VA_ARGS__))
+
+#define LOG_CONTEXT_PUSHF(...) \
+        LOG_CONTEXT_PUSH(snprintf_ok((char[LINE_MAX]) {}, LINE_MAX, __VA_ARGS__))
+
+#define _LOG_CONTEXT_PUSH_STRV(strv, c) \
+        _unused_ _cleanup_(log_context_freep) LogContext *c = log_context_new(strv, /*owned=*/ false);
+
+#define LOG_CONTEXT_PUSH_STRV(strv) \
+        _LOG_CONTEXT_PUSH_STRV(strv, UNIQ_T(c, UNIQ))
+
+/* LOG_CONTEXT_CONSUME_STR()/LOG_CONTEXT_CONSUME_STRV() are identical to
+ * LOG_CONTEXT_PUSH_STR()/LOG_CONTEXT_PUSH_STRV() except they take ownership of the given str/strv argument.
+ */
+
+#define _LOG_CONTEXT_CONSUME_STR(s, c, strv) \
+        _unused_ _cleanup_strv_free_ strv = strv_new(s);                                                \
+        if (!strv)                                                                                      \
+                free(s);                                                                                \
+        _unused_ _cleanup_(log_context_freep) LogContext *c = log_context_new_consume(TAKE_PTR(strv))
+
+#define LOG_CONTEXT_CONSUME_STR(s) \
+        _LOG_CONTEXT_CONSUME_STR(s, UNIQ_T(c, UNIQ), UNIQ_T(sv, UNIQ))
+
+#define _LOG_CONTEXT_CONSUME_STRV(strv, c) \
+        _unused_ _cleanup_(log_context_freep) LogContext *c = log_context_new_consume(strv);
+
+#define LOG_CONTEXT_CONSUME_STRV(strv) \
+        _LOG_CONTEXT_CONSUME_STRV(strv, UNIQ_T(c, UNIQ))
diff --git a/src/basic/stdio-util.h b/src/basic/stdio-util.h
index f647f125ac..4e93ac90c9 100644
--- a/src/basic/stdio-util.h
+++ b/src/basic/stdio-util.h
@@ -7,15 +7,20 @@
 #include <sys/types.h>
 
 #include "macro.h"
-#include "memory-util.h"
 
-#define snprintf_ok(buf, len, fmt, ...)                                 \
-        ({                                                              \
-                char *_buf = (buf);                                     \
-                size_t _len = (len);                                    \
-                int _snpf = snprintf(_buf, _len, (fmt), ##__VA_ARGS__); \
-                _snpf >= 0 && (size_t) _snpf < _len ? _buf : NULL;      \
-        })
+_printf_(3, 4)
+static inline char *snprintf_ok(char *buf, size_t len, const char *format, ...) {
+        va_list ap;
+        int r;
+
+        va_start(ap, format);
+        DISABLE_WARNING_FORMAT_NONLITERAL;
+        r = vsnprintf(buf, len, format, ap);
+        REENABLE_WARNING;
+        va_end(ap);
+
+        return r >= 0 && (size_t) r < len ? buf : NULL;
+}
 
 #define xsprintf(buf, fmt, ...) \
         assert_message_se(snprintf_ok(buf, ELEMENTSOF(buf), fmt, ##__VA_ARGS__), "xsprintf: " #buf "[] must be big enough")
@@ -26,7 +31,7 @@ do {                                                                    \
         size_t _i, _k;                                                  \
         /* See https://github.com/google/sanitizers/issues/992 */       \
         if (HAS_FEATURE_MEMORY_SANITIZER)                               \
-                zero(_argtypes);                                        \
+                memset(_argtypes, 0, sizeof(_argtypes));                \
         _k = parse_printf_format((format), ELEMENTSOF(_argtypes), _argtypes); \
         assert(_k < ELEMENTSOF(_argtypes));                             \
         for (_i = 0; _i < _k; _i++) {                                   \
diff --git a/src/basic/strv.c b/src/basic/strv.c
index 74e87046cc..2b7a61d442 100644
--- a/src/basic/strv.c
+++ b/src/basic/strv.c
@@ -789,6 +789,22 @@ rollback:
         return -ENOMEM;
 }
 
+int strv_extend_assignment(char ***l, const char *lhs, const char *rhs) {
+        char *j;
+
+        assert(l);
+        assert(lhs);
+
+        if (!rhs) /* value is optional, in which case we suppress the field */
+                return 0;
+
+        j = strjoin(lhs, "=", rhs);
+        if (!j)
+                return -ENOMEM;
+
+        return strv_consume(l, j);
+}
+
 int fputstrv(FILE *f, char * const *l, const char *separator, bool *space) {
         bool b = false;
         int r;
diff --git a/src/basic/strv.h b/src/basic/strv.h
index f82c76589d..1f8da85fcc 100644
--- a/src/basic/strv.h
+++ b/src/basic/strv.h
@@ -241,6 +241,8 @@ char** strv_skip(char **l, size_t n);
 
 int strv_extend_n(char ***l, const char *value, size_t n);
 
+int strv_extend_assignment(char ***l, const char *lhs, const char *rhs);
+
 int fputstrv(FILE *f, char * const *l, const char *separator, bool *space);
 
 #define strv_free_and_replace(a, b)             \
diff --git a/src/core/execute.c b/src/core/execute.c
index f5d57a63b5..ac3f096b0d 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -6650,7 +6650,7 @@ void exec_command_append_list(ExecCommand **l, ExecCommand *e) {
 
         if (*l) {
                 /* It's kind of important, that we keep the order here */
-                LIST_FIND_TAIL(command, *l, end);
+                end = LIST_FIND_TAIL(command, *l);
                 LIST_INSERT_AFTER(command, *l, end, e);
         } else
               *l = e;
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 6c55bc5187..0ed2d1b31d 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -680,7 +680,7 @@ int config_parse_socket_listen(
         p->n_auxiliary_fds = 0;
         p->socket = s;
 
-        LIST_FIND_TAIL(port, s->ports, tail);
+        tail = LIST_FIND_TAIL(port, s->ports);
         LIST_INSERT_AFTER(port, s->ports, tail, p);
 
         p = NULL;
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 07168f660b..9719f97c02 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -4667,3 +4667,26 @@ _public_ int sd_bus_message_sensitive(sd_bus_message *m) {
         m->sensitive = true;
         return 0;
 }
+
+char** bus_message_make_log_fields(sd_bus_message *m) {
+        _cleanup_strv_free_ char **strv = NULL;
+
+        assert(m);
+
+        (void) strv_extend_assignment(&strv, "DBUS_MESSAGE_TYPE", bus_message_type_to_string(m->header->type));
+        (void) strv_extend_assignment(&strv, "DBUS_SENDER", sd_bus_message_get_sender(m));
+        (void) strv_extend_assignment(&strv, "DBUS_DESTINATION", sd_bus_message_get_destination(m));
+        (void) strv_extend_assignment(&strv, "DBUS_PATH", sd_bus_message_get_path(m));
+        (void) strv_extend_assignment(&strv, "DBUS_INTERFACE", sd_bus_message_get_interface(m));
+        (void) strv_extend_assignment(&strv, "DBUS_MEMBER", sd_bus_message_get_member(m));
+
+        (void) strv_extendf(&strv, "DBUS_MESSAGE_COOKIE=%" PRIu64, BUS_MESSAGE_COOKIE(m));
+        if (m->reply_cookie != 0)
+                (void) strv_extendf(&strv, "DBUS_MESSAGE_REPLY_COOKIE=%" PRIu64, m->reply_cookie);
+
+        (void) strv_extend_assignment(&strv, "DBUS_SIGNATURE", m->root_container.signature);
+        (void) strv_extend_assignment(&strv, "DBUS_ERROR_NAME", m->error.name);
+        (void) strv_extend_assignment(&strv, "DBUS_ERROR_MESSAGE", m->error.message);
+
+        return TAKE_PTR(strv);
+}
diff --git a/src/libsystemd/sd-bus/bus-message.h b/src/libsystemd/sd-bus/bus-message.h
index 0439fbd45a..76f0d853d3 100644
--- a/src/libsystemd/sd-bus/bus-message.h
+++ b/src/libsystemd/sd-bus/bus-message.h
@@ -187,3 +187,5 @@ void bus_message_set_sender_local(sd_bus *bus, sd_bus_message *m);
 
 sd_bus_message* bus_message_ref_queued(sd_bus_message *m, sd_bus *bus);
 sd_bus_message* bus_message_unref_queued(sd_bus_message *m, sd_bus *bus);
+
+char** bus_message_make_log_fields(sd_bus_message *m);
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index d85dcc52c1..10796e25c7 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -2928,6 +2928,7 @@ static int process_fd_check(sd_bus *bus, sd_bus_message *m) {
 }
 
 static int process_message(sd_bus *bus, sd_bus_message *m) {
+        _unused_ _cleanup_(log_context_freep) LogContext *c = NULL;
         int r;
 
         assert(bus);
@@ -2936,6 +2937,9 @@ static int process_message(sd_bus *bus, sd_bus_message *m) {
         bus->current_message = m;
         bus->iteration_counter++;
 
+        if (log_context_enabled())
+                c = log_context_new_consume(bus_message_make_log_fields(m));
+
         log_debug_bus_message(m);
 
         r = process_hello(bus, m);
diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
index 049b3aa97f..0d2eea5f59 100644
--- a/src/libsystemd/sd-device/device-monitor.c
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -242,11 +242,15 @@ _public_ int sd_device_monitor_stop(sd_device_monitor *m) {
 
 static int device_monitor_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
         _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        _unused_ _cleanup_(log_context_freep) LogContext *c = NULL;
         sd_device_monitor *m = ASSERT_PTR(userdata);
 
         if (device_monitor_receive_device(m, &device) <= 0)
                 return 0;
 
+        if (log_context_enabled())
+                c = log_context_new_consume(device_make_log_fields(device));
+
         if (m->callback)
                 return m->callback(m, device, m->userdata);
 
diff --git a/src/libsystemd/sd-device/device-util.c b/src/libsystemd/sd-device/device-util.c
index 56acec67f6..47c5d98896 100644
--- a/src/libsystemd/sd-device/device-util.c
+++ b/src/libsystemd/sd-device/device-util.c
@@ -5,6 +5,7 @@
 #include "devnum-util.h"
 #include "fd-util.h"
 #include "string-util.h"
+#include "strv.h"
 
 int devname_from_devnum(mode_t mode, dev_t devnum, char **ret) {
         _cleanup_(sd_device_unrefp) sd_device *dev = NULL;
@@ -63,3 +64,78 @@ int device_open_from_devnum(mode_t mode, dev_t devnum, int flags, char **ret) {
 
         return TAKE_FD(fd);
 }
+
+static int add_string_field(
+                sd_device *device,
+                const char *field,
+                int (*func)(sd_device *dev, const char **s),
+                char ***strv) {
+
+        const char *s;
+        int r;
+
+        assert(device);
+        assert(field);
+        assert(func);
+        assert(strv);
+
+        r = func(device, &s);
+        if (r < 0 && r != -ENOENT)
+                log_device_debug_errno(device, r, "Failed to get device \"%s\" property, ignoring: %m", field);
+        if (r >= 0)
+                (void) strv_extend_assignment(strv, field, s);
+
+        return 0;
+}
+
+char** device_make_log_fields(sd_device *device) {
+        _cleanup_strv_free_ char **strv = NULL;
+        dev_t devnum;
+        int ifindex;
+        sd_device_action_t action;
+        uint64_t seqnum, diskseq;
+        int r;
+
+        assert(device);
+
+        (void) add_string_field(device, "SYSPATH", sd_device_get_syspath, &strv);
+        (void) add_string_field(device, "SUBSYSTEM", sd_device_get_subsystem, &strv);
+        (void) add_string_field(device, "DEVTYPE", sd_device_get_devtype, &strv);
+        (void) add_string_field(device, "DRIVER", sd_device_get_driver, &strv);
+        (void) add_string_field(device, "DEVPATH", sd_device_get_devpath, &strv);
+        (void) add_string_field(device, "DEVNAME", sd_device_get_devname, &strv);
+        (void) add_string_field(device, "SYSNAME", sd_device_get_sysname, &strv);
+        (void) add_string_field(device, "SYSNUM", sd_device_get_sysnum, &strv);
+
+        r = sd_device_get_devnum(device, &devnum);
+        if (r < 0 && r != -ENOENT)
+                log_device_debug_errno(device, r, "Failed to get device \"DEVNUM\" property, ignoring: %m");
+        if (r >= 0)
+                (void) strv_extendf(&strv, "DEVNUM="DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(devnum));
+
+        r = sd_device_get_ifindex(device, &ifindex);
+        if (r < 0 && r != -ENOENT)
+                log_device_debug_errno(device, r, "Failed to get device \"IFINDEX\" property, ignoring: %m");
+        if (r >= 0)
+                (void) strv_extendf(&strv, "IFINDEX=%i", ifindex);
+
+        r = sd_device_get_action(device, &action);
+        if (r < 0 && r != -ENOENT)
+                log_device_debug_errno(device, r, "Failed to get device \"ACTION\" property, ignoring: %m");
+        if (r >= 0)
+                (void) strv_extendf(&strv, "ACTION=%s", device_action_to_string(action));
+
+        r = sd_device_get_seqnum(device, &seqnum);
+        if (r < 0 && r != -ENOENT)
+                log_device_debug_errno(device, r, "Failed to get device \"SEQNUM\" property, ignoring: %m");
+        if (r >= 0)
+                (void) strv_extendf(&strv, "SEQNUM=%"PRIu64, seqnum);
+
+        r = sd_device_get_diskseq(device, &diskseq);
+        if (r < 0 && r != -ENOENT)
+                log_device_debug_errno(device, r, "Failed to get device \"DISKSEQ\" property, ignoring: %m");
+        if (r >= 0)
+                (void) strv_extendf(&strv, "DISKSEQ=%"PRIu64, diskseq);
+
+        return TAKE_PTR(strv);
+}
diff --git a/src/libsystemd/sd-device/device-util.h b/src/libsystemd/sd-device/device-util.h
index f139e114a8..a1b5e91edf 100644
--- a/src/libsystemd/sd-device/device-util.h
+++ b/src/libsystemd/sd-device/device-util.h
@@ -99,3 +99,5 @@ static inline int devname_from_stat_rdev(const struct stat *st, char **ret) {
         return devname_from_devnum(st->st_mode, st->st_rdev, ret);
 }
 int device_open_from_devnum(mode_t mode, dev_t devnum, int flags, char **ret);
+
+char** device_make_log_fields(sd_device *device);
diff --git a/src/resolve/resolved-dns-search-domain.c b/src/resolve/resolved-dns-search-domain.c
index 647c0bd1f9..a11b21350a 100644
--- a/src/resolve/resolved-dns-search-domain.c
+++ b/src/resolve/resolved-dns-search-domain.c
@@ -123,13 +123,13 @@ void dns_search_domain_move_back_and_unmark(DnsSearchDomain *d) {
 
         case DNS_SEARCH_DOMAIN_LINK:
                 assert(d->link);
-                LIST_FIND_TAIL(domains, d, tail);
+                tail = LIST_FIND_TAIL(domains, d);
                 LIST_REMOVE(domains, d->link->search_domains, d);
                 LIST_INSERT_AFTER(domains, d->link->search_domains, tail, d);
                 break;
 
         case DNS_SEARCH_DOMAIN_SYSTEM:
-                LIST_FIND_TAIL(domains, d, tail);
+                tail = LIST_FIND_TAIL(domains, d);
                 LIST_REMOVE(domains, d->manager->search_domains, d);
                 LIST_INSERT_AFTER(domains, d->manager->search_domains, tail, d);
                 break;
diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c
index 8ff513fa33..342a90abcb 100644
--- a/src/resolve/resolved-dns-server.c
+++ b/src/resolve/resolved-dns-server.c
@@ -195,19 +195,19 @@ void dns_server_move_back_and_unmark(DnsServer *s) {
 
         case DNS_SERVER_LINK:
                 assert(s->link);
-                LIST_FIND_TAIL(servers, s, tail);
+                tail = LIST_FIND_TAIL(servers, s);
                 LIST_REMOVE(servers, s->link->dns_servers, s);
                 LIST_INSERT_AFTER(servers, s->link->dns_servers, tail, s);
                 break;
 
         case DNS_SERVER_SYSTEM:
-                LIST_FIND_TAIL(servers, s, tail);
+                tail = LIST_FIND_TAIL(servers, s);
                 LIST_REMOVE(servers, s->manager->dns_servers, s);
                 LIST_INSERT_AFTER(servers, s->manager->dns_servers, tail, s);
                 break;
 
         case DNS_SERVER_FALLBACK:
-                LIST_FIND_TAIL(servers, s, tail);
+                tail = LIST_FIND_TAIL(servers, s);
                 LIST_REMOVE(servers, s->manager->fallback_dns_servers, s);
                 LIST_INSERT_AFTER(servers, s->manager->fallback_dns_servers, tail, s);
                 break;
diff --git a/src/systemctl/systemctl-show.c b/src/systemctl/systemctl-show.c
index db489a671e..3f88d1a2cc 100644
--- a/src/systemctl/systemctl-show.c
+++ b/src/systemctl/systemctl-show.c
@@ -954,7 +954,7 @@ static int map_exec(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_e
         if (!info)
                 return -ENOMEM;
 
-        LIST_FIND_TAIL(exec_status_info_list, i->exec_status_info_list, last);
+        last = LIST_FIND_TAIL(exec_status_info_list, i->exec_status_info_list);
 
         while ((r = exec_status_info_deserialize(m, info, is_ex_prop)) > 0) {
 
diff --git a/src/test/test-list.c b/src/test/test-list.c
index ea45f5b95c..307c1bf936 100644
--- a/src/test/test-list.c
+++ b/src/test/test-list.c
@@ -19,7 +19,7 @@ int main(int argc, const char *argv[]) {
         for (i = 0; i < ELEMENTSOF(items); i++) {
                 LIST_INIT(item_list, &items[i]);
                 assert_se(LIST_JUST_US(item_list, &items[i]));
-                LIST_PREPEND(item_list, head, &items[i]);
+                assert_se(LIST_PREPEND(item_list, head, &items[i]) == &items[i]);
         }
 
         i = 0;
@@ -55,14 +55,13 @@ int main(int argc, const char *argv[]) {
         assert_se(items[2].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        list_item *cursor;
-        LIST_FIND_HEAD(item_list, &items[0], cursor);
+        list_item *cursor = LIST_FIND_HEAD(item_list, &items[0]);
         assert_se(cursor == &items[3]);
 
-        LIST_FIND_TAIL(item_list, &items[3], cursor);
+        cursor = LIST_FIND_TAIL(item_list, &items[3]);
         assert_se(cursor == &items[0]);
 
-        LIST_REMOVE(item_list, head, &items[1]);
+        assert_se(LIST_REMOVE(item_list, head, &items[1]) == &items[1]);
         assert_se(LIST_JUST_US(item_list, &items[1]));
 
         assert_se(items[0].item_list_next == NULL);
@@ -73,7 +72,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[2].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_INSERT_AFTER(item_list, head, &items[3], &items[1]);
+        assert_se(LIST_INSERT_AFTER(item_list, head, &items[3], &items[1]) == &items[1]);
         assert_se(items[0].item_list_next == NULL);
         assert_se(items[2].item_list_next == &items[0]);
         assert_se(items[1].item_list_next == &items[2]);
@@ -84,7 +83,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[1].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_REMOVE(item_list, head, &items[1]);
+        assert_se(LIST_REMOVE(item_list, head, &items[1]) == &items[1]);
         assert_se(LIST_JUST_US(item_list, &items[1]));
 
         assert_se(items[0].item_list_next == NULL);
@@ -95,7 +94,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[2].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_INSERT_BEFORE(item_list, head, &items[2], &items[1]);
+        assert_se(LIST_INSERT_BEFORE(item_list, head, &items[2], &items[1]) == &items[1]);
         assert_se(items[0].item_list_next == NULL);
         assert_se(items[2].item_list_next == &items[0]);
         assert_se(items[1].item_list_next == &items[2]);
@@ -106,7 +105,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[1].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_REMOVE(item_list, head, &items[0]);
+        assert_se(LIST_REMOVE(item_list, head, &items[0]) == &items[0]);
         assert_se(LIST_JUST_US(item_list, &items[0]));
 
         assert_se(items[2].item_list_next == NULL);
@@ -117,7 +116,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[1].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_INSERT_BEFORE(item_list, head, &items[3], &items[0]);
+        assert_se(LIST_INSERT_BEFORE(item_list, head, &items[3], &items[0]) == &items[0]);
         assert_se(items[2].item_list_next == NULL);
         assert_se(items[1].item_list_next == &items[2]);
         assert_se(items[3].item_list_next == &items[1]);
@@ -129,7 +128,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[0].item_list_prev == NULL);
         assert_se(head == &items[0]);
 
-        LIST_REMOVE(item_list, head, &items[0]);
+        assert_se(LIST_REMOVE(item_list, head, &items[0]) == &items[0]);
         assert_se(LIST_JUST_US(item_list, &items[0]));
 
         assert_se(items[2].item_list_next == NULL);
@@ -140,7 +139,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[1].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_INSERT_BEFORE(item_list, head, NULL, &items[0]);
+        assert_se(LIST_INSERT_BEFORE(item_list, head, NULL, &items[0]) == &items[0]);
         assert_se(items[0].item_list_next == NULL);
         assert_se(items[2].item_list_next == &items[0]);
         assert_se(items[1].item_list_next == &items[2]);
@@ -151,7 +150,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[1].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_REMOVE(item_list, head, &items[0]);
+        assert_se(LIST_REMOVE(item_list, head, &items[0]) == &items[0]);
         assert_se(LIST_JUST_US(item_list, &items[0]));
 
         assert_se(items[2].item_list_next == NULL);
@@ -162,7 +161,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[1].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_REMOVE(item_list, head, &items[1]);
+        assert_se(LIST_REMOVE(item_list, head, &items[1]) == &items[1]);
         assert_se(LIST_JUST_US(item_list, &items[1]));
 
         assert_se(items[2].item_list_next == NULL);
@@ -171,18 +170,18 @@ int main(int argc, const char *argv[]) {
         assert_se(items[2].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_REMOVE(item_list, head, &items[2]);
+        assert_se(LIST_REMOVE(item_list, head, &items[2]) == &items[2]);
         assert_se(LIST_JUST_US(item_list, &items[2]));
         assert_se(LIST_JUST_US(item_list, head));
 
-        LIST_REMOVE(item_list, head, &items[3]);
+        assert_se(LIST_REMOVE(item_list, head, &items[3]) == &items[3]);
         assert_se(LIST_JUST_US(item_list, &items[3]));
 
         assert_se(head == NULL);
 
         for (i = 0; i < ELEMENTSOF(items); i++) {
                 assert_se(LIST_JUST_US(item_list, &items[i]));
-                LIST_APPEND(item_list, head, &items[i]);
+                assert_se(LIST_APPEND(item_list, head, &items[i]) == &items[i]);
         }
 
         assert_se(!LIST_JUST_US(item_list, head));
@@ -198,20 +197,20 @@ int main(int argc, const char *argv[]) {
         assert_se(items[3].item_list_prev == &items[2]);
 
         for (i = 0; i < ELEMENTSOF(items); i++)
-                LIST_REMOVE(item_list, head, &items[i]);
+                assert_se(LIST_REMOVE(item_list, head, &items[i]) == &items[i]);
 
         assert_se(head == NULL);
 
         for (i = 0; i < ELEMENTSOF(items) / 2; i++) {
                 LIST_INIT(item_list, &items[i]);
                 assert_se(LIST_JUST_US(item_list, &items[i]));
-                LIST_PREPEND(item_list, head, &items[i]);
+                assert_se(LIST_PREPEND(item_list, head, &items[i]) == &items[i]);
         }
 
         for (i = ELEMENTSOF(items) / 2; i < ELEMENTSOF(items); i++) {
                 LIST_INIT(item_list, &items[i]);
                 assert_se(LIST_JUST_US(item_list, &items[i]));
-                LIST_PREPEND(item_list, head2, &items[i]);
+                assert_se(LIST_PREPEND(item_list, head2, &items[i]) == &items[i]);
         }
 
         assert_se(items[0].item_list_next == NULL);
@@ -224,7 +223,7 @@ int main(int argc, const char *argv[]) {
         assert_se(items[2].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_JOIN(item_list, head2, head);
+        assert_se(LIST_JOIN(item_list, head2, head) == head2);
         assert_se(head == NULL);
 
         assert_se(items[0].item_list_next == NULL);
@@ -237,18 +236,18 @@ int main(int argc, const char *argv[]) {
         assert_se(items[2].item_list_prev == &items[3]);
         assert_se(items[3].item_list_prev == NULL);
 
-        LIST_JOIN(item_list, head, head2);
+        assert_se(LIST_JOIN(item_list, head, head2) == head);
         assert_se(head2 == NULL);
         assert_se(head);
 
         for (i = 0; i < ELEMENTSOF(items); i++)
-                LIST_REMOVE(item_list, head, &items[i]);
+                assert_se(LIST_REMOVE(item_list, head, &items[i]) == &items[i]);
 
         assert_se(head == NULL);
 
-        LIST_PREPEND(item_list, head, items + 0);
-        LIST_PREPEND(item_list, head, items + 1);
-        LIST_PREPEND(item_list, head, items + 2);
+        assert_se(LIST_PREPEND(item_list, head, items + 0) == items + 0);
+        assert_se(LIST_PREPEND(item_list, head, items + 1) == items + 1);
+        assert_se(LIST_PREPEND(item_list, head, items + 2) == items + 2);
 
         assert_se(LIST_POP(item_list, head) == items + 2);
         assert_se(LIST_POP(item_list, head) == items + 1);
diff --git a/src/test/test-log.c b/src/test/test-log.c
index f21d88f39a..30c536d5c7 100644
--- a/src/test/test-log.c
+++ b/src/test/test-log.c
@@ -7,6 +7,7 @@
 #include "log.h"
 #include "process-util.h"
 #include "string-util.h"
+#include "strv.h"
 
 assert_cc(IS_SYNTHETIC_ERRNO(SYNTHETIC_ERRNO(EINVAL)));
 assert_cc(!IS_SYNTHETIC_ERRNO(EINVAL));
@@ -69,6 +70,75 @@ static void test_log_syntax(void) {
         assert_se(log_syntax("unit", LOG_ERR, "filename", 10, SYNTHETIC_ERRNO(ENOTTY), "ENOTTY: %s: %m", "hogehoge") == -ENOTTY);
 }
 
+static void test_log_context(void) {
+        {
+                char **strv = STRV_MAKE("FIRST=abc", "SECOND=qrs");
+
+                LOG_CONTEXT_PUSH("THIRD=pfs");
+                LOG_CONTEXT_PUSH("FOURTH=def");
+                LOG_CONTEXT_PUSH_STRV(strv);
+                LOG_CONTEXT_PUSH_STRV(strv);
+
+                /* Test that the log context was set up correctly. */
+                assert_se(log_context_num_contexts() == 4);
+                assert_se(log_context_num_fields() == 6);
+
+                /* Test that everything still works with modifications to the log context. */
+                test_log_struct();
+                test_long_lines();
+                test_log_syntax();
+
+                {
+                        LOG_CONTEXT_PUSH("FIFTH=123");
+                        LOG_CONTEXT_PUSH_STRV(strv);
+
+                        /* Check that our nested fields got added correctly. */
+                        assert_se(log_context_num_contexts() == 6);
+                        assert_se(log_context_num_fields() == 9);
+
+                        /* Test that everything still works in a nested block. */
+                        test_log_struct();
+                        test_long_lines();
+                        test_log_syntax();
+                }
+
+                /* Check that only the fields from the nested block got removed. */
+                assert_se(log_context_num_contexts() == 4);
+                assert_se(log_context_num_fields() == 6);
+        }
+
+        assert_se(log_context_num_contexts() == 0);
+        assert_se(log_context_num_fields() == 0);
+
+        {
+                _cleanup_(log_context_freep) LogContext *ctx = NULL;
+
+                char **strv = STRV_MAKE("SIXTH=ijn", "SEVENTH=PRP");
+                assert_se(ctx = log_context_new(strv, /*owned=*/ false));
+
+                assert_se(log_context_num_contexts() == 1);
+                assert_se(log_context_num_fields() == 2);
+
+                /* Test that everything still works with a manually configured log context. */
+                test_log_struct();
+                test_long_lines();
+                test_log_syntax();
+        }
+
+        {
+                char **strv = NULL;
+
+                assert_se(strv = strv_new("ABC", "DEF"));
+                LOG_CONTEXT_CONSUME_STRV(strv);
+
+                assert_se(log_context_num_contexts() == 1);
+                assert_se(log_context_num_fields() == 2);
+        }
+
+        assert_se(log_context_num_contexts() == 0);
+        assert_se(log_context_num_fields() == 0);
+}
+
 int main(int argc, char* argv[]) {
         test_file();
 
@@ -81,6 +151,7 @@ int main(int argc, char* argv[]) {
                 test_log_struct();
                 test_long_lines();
                 test_log_syntax();
+                test_log_context();
         }
 
         return 0;
diff --git a/src/test/test-strv.c b/src/test/test-strv.c
index 9208faafa4..5c03eaa960 100644
--- a/src/test/test-strv.c
+++ b/src/test/test-strv.c
@@ -942,4 +942,16 @@ TEST(strv_fnmatch) {
         assert_se(pos == 1);
 }
 
+TEST(strv_extend_join) {
+        _cleanup_strv_free_ char **v = NULL;
+
+        assert_se(strv_extend_assignment(&v, "MESSAGE", "ABC") >= 0);
+        assert_se(strv_extend_assignment(&v, "ABC", "QER") >= 0);
+        assert_se(strv_extend_assignment(&v, "MISSING", NULL) >= 0);
+
+        assert_se(strv_length(v) == 2);
+        assert_se(streq(v[0], "MESSAGE=ABC"));
+        assert_se(streq(v[1], "ABC=QER"));
+}
+
 DEFINE_TEST_MAIN(LOG_INFO);
diff --git a/src/timesync/timesyncd-server.c b/src/timesync/timesyncd-server.c
index 3b7d79323f..7aa1551baf 100644
--- a/src/timesync/timesyncd-server.c
+++ b/src/timesync/timesyncd-server.c
@@ -37,7 +37,7 @@ int server_address_new(
 
         memcpy(&a->sockaddr, sockaddr, socklen);
 
-        LIST_FIND_TAIL(addresses, n->addresses, tail);
+        tail = LIST_FIND_TAIL(addresses, n->addresses);
         LIST_INSERT_AFTER(addresses, n->addresses, tail, a);
 
         if (ret)