basic/log: always ignore errno from the enviornment (#8841)

This extends the change done in b29f6480ec to other logging functions.

This actually fixes some bugs in callers of log_struct(), for example
config_parse_alias() called 'return log_syntax(..., 0, ...)' which could result
in a bogus non-zero return value.

Calls to log_object() and log_format_iovec() — which is only used by
server_driver_message() — appear correct.

diff --git a/src/basic/log.c b/src/basic/log.c
index 6d5616730dd9caf4d0eda43f12c12731cd96ce85..ed02a4b906c4f4fdb9213a3eaa016066c3950d8d 100644 (file)
--- a/src/basic/log.c
+++ b/src/basic/log.c
@@ -751,9 +751,8 @@ static int log_object_internalv(
         if (_likely_(LOG_PRI(level) > log_max_level[LOG_REALM_SYSTEMD]))
                 return -error;
 
-        /* Make sure that %m maps to the specified error */
-        if (error != 0)
-                errno = error;
+        /* Make sure that %m maps to the specified error (or "Success"). */
+        errno = error;
 
         /* Prepend the object name before the message */
         if (object) {
@@ -876,8 +875,7 @@ int log_format_iovec(
                  * since vasprintf() leaves it afterwards at
                  * an undefined location */
 
-                if (error != 0)
-                        errno = error;
+                errno = error;
 
                 va_copy(aq, ap);
                 r = vasprintf(&m, format, aq);
@@ -980,8 +978,7 @@ int log_struct_internal(
         while (format) {
                 va_list aq;
 
-                if (error != 0)
-                        errno = error;
+                errno = error;
 
                 va_copy(aq, ap);
                 (void) vsnprintf(buf, sizeof buf, format, aq);
@@ -1283,8 +1280,7 @@ int log_syntax_internal(
         if (log_target == LOG_TARGET_NULL)
                 return -error;
 
-        if (error != 0)
-                errno = error;
+        errno = error;
 
         va_start(ap, format);
         (void) vsnprintf(buffer, sizeof buffer, format, ap);