log: change log_xyz_errno() calls to always return the negative error

This enables us to write things like this:

    int open_some_file(void) {

            fd = open("/dev/foobar", O_RDWR|O_CLOEXEC);
            if (fd < 0)
                    return log_error_errno(errno, "Failed to reboot: %m");

            return fd;
    }

Which is function that returns -errno on failure, as well as printing an
error message, all in one line.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/shared/log.h b/src/shared/log.h
index 3180dfd638..a6b933605d 100644
--- a/src/shared/log.h
+++ b/src/shared/log.h
@@ -155,11 +155,13 @@ void log_assert_failed_return(
                 const char *func);
 
 /* Logging with level */
-#define log_full_errno(level, error, ...)                               \
-        do {                                                            \
-                if (log_get_max_level() >= (level))                     \
-                        log_internal((level), error, __FILE__, __LINE__, __func__, __VA_ARGS__); \
-        } while (false)
+#define log_full_errno(level, error, ...)                                         \
+        ({                                                                        \
+                int _l = (level), _e = (error);                                   \
+                (log_get_max_level() >= _l)                                       \
+                ? log_internal(_l, _e, __FILE__, __LINE__, __func__, __VA_ARGS__) \
+                : -abs(_e); \
+        })
 
 #define log_full(level, ...) log_full_errno(level, 0, __VA_ARGS__)