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/ipv4ll-internal.h b/src/libsystemd-network/ipv4ll-internal.h
index fe5ef8e2b8..7b5d3729e5 100644
--- a/src/libsystemd-network/ipv4ll-internal.h
+++ b/src/libsystemd-network/ipv4ll-internal.h
@@ -35,4 +35,4 @@ void arp_packet_probe(struct ether_arp *arp, be32_t pa, const struct ether_addr
 void arp_packet_announcement(struct ether_arp *arp, be32_t pa, const struct ether_addr *ha);
 int arp_packet_verify_headers(struct ether_arp *arp);
 
-#define log_ipv4ll(ll, fmt, ...) log_meta(LOG_DEBUG, __FILE__, __LINE__, __func__, "IPv4LL: " fmt, ##__VA_ARGS__)
+#define log_ipv4ll(ll, fmt, ...) log_meta(LOG_DEBUG, 0, __FILE__, __LINE__, __func__, "IPv4LL: " fmt, ##__VA_ARGS__)