log: add an "error" parameter to all low-level logging calls and intrdouce log_error_errno() as log calls that take error numbers

This change has two benefits:

- The format string %m will now resolve to the specified error (or to
  errno if the specified error is 0. This allows getting rid of a ton of
  strerror() invocations, a function that is not thread-safe.

- The specified error can be passed to the journal in the ERRNO= field.

Now of course, we just need somebody to convert all cases of this:

        log_error("Something happened: %s", strerror(-r));

into thus:

        log_error_errno(-r, "Something happened: %m");

1 files changed, 1 insertions, 1 deletions

diff --git a/src/network/networkd-link.h b/src/network/networkd-link.h
index 7acf404f8..5eb4b8893 100644
--- a/src/network/networkd-link.h
+++ b/src/network/networkd-link.h
@@ -132,7 +132,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(Link*, link_unref);
 
 /* Macros which append INTERFACE= to the message */
 
-#define log_full_link(level, link, fmt, ...) log_meta_object(level, __FILE__, __LINE__, __func__, "INTERFACE=", link->ifname, "%-*s: " fmt, IFNAMSIZ, link->ifname, ##__VA_ARGS__)
+#define log_full_link(level, link, fmt, ...) log_meta_object(level, 0, __FILE__, __LINE__, __func__, "INTERFACE=", link->ifname, "%-*s: " fmt, IFNAMSIZ, link->ifname, ##__VA_ARGS__)
 #define log_debug_link(link, ...)       log_full_link(LOG_DEBUG, link, ##__VA_ARGS__)
 #define log_info_link(link, ...)        log_full_link(LOG_INFO, link, ##__VA_ARGS__)
 #define log_notice_link(link, ...)      log_full_link(LOG_NOTICE, link, ##__VA_ARGS__)