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/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
index 480da22c01..6c2c248696 100644
--- a/src/libsystemd-network/dhcp-server-internal.h
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -79,7 +79,7 @@ typedef struct DHCPRequest {
 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_server*, sd_dhcp_server_unref);
 #define _cleanup_dhcp_server_unref_ _cleanup_(sd_dhcp_server_unrefp)
 
-#define log_dhcp_server(client, fmt, ...) log_meta(LOG_DEBUG, __FILE__, __LINE__, __func__, "DHCP SERVER: " fmt, ##__VA_ARGS__)
+#define log_dhcp_server(client, fmt, ...) log_meta(LOG_DEBUG, 0, __FILE__, __LINE__, __func__, "DHCP SERVER: " fmt, ##__VA_ARGS__)
 
 int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
                                size_t length);