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, 35 insertions, 14 deletions

diff --git a/src/shared/log.h b/src/shared/log.h
index 8141e9dbb0..9dd68df500 100644
--- a/src/shared/log.h
+++ b/src/shared/log.h
@@ -77,44 +77,49 @@ void log_parse_environment(void);
 
 int log_meta(
                 int level,
+                int error,
                 const char*file,
                 int line,
                 const char *func,
-                const char *format, ...) _printf_(5,6);
+                const char *format, ...) _printf_(6,7);
 
 int log_metav(
                 int level,
+                int error,
                 const char*file,
                 int line,
                 const char *func,
                 const char *format,
-                va_list ap) _printf_(5,0);
+                va_list ap) _printf_(6,0);
 
 int log_meta_object(
                 int level,
+                int error,
                 const char*file,
                 int line,
                 const char *func,
                 const char *object_name,
                 const char *object,
-                const char *format, ...) _printf_(7,8);
+                const char *format, ...) _printf_(8,9);
 
 int log_metav_object(
                 int level,
+                int error,
                 const char*file,
                 int line,
                 const char *func,
                 const char *object_name,
                 const char *object,
                 const char *format,
-                va_list ap) _printf_(7,0);
+                va_list ap) _printf_(8,0);
 
 int log_struct_internal(
                 int level,
+                int error,
                 const char *file,
                 int line,
                 const char *func,
-                const char *format, ...) _printf_(5,0) _sentinel_;
+                const char *format, ...) _printf_(6,0) _sentinel_;
 
 int log_oom_internal(
                 const char *file,
@@ -124,11 +129,13 @@ int log_oom_internal(
 /* This modifies the buffer passed! */
 int log_dump_internal(
                 int level,
+                int error,
                 const char*file,
                 int line,
                 const char *func,
                 char *buffer);
 
+/* Logging for various assertions */
 noreturn void log_assert_failed(
                 const char *text,
                 const char *file,
@@ -147,12 +154,16 @@ void log_assert_failed_return(
                 int line,
                 const char *func);
 
-#define log_full(level, ...) \
-do { \
-        if (log_get_max_level() >= (level)) \
-                log_meta((level), __FILE__, __LINE__, __func__, __VA_ARGS__); \
-} while (0)
+/* Logging with level */
+#define log_full_errno(level, error, ...)                               \
+        do {                                                            \
+                if (log_get_max_level() >= (level))                     \
+                        log_meta((level), error, __FILE__, __LINE__, __func__, __VA_ARGS__); \
+        } while (false)
 
+#define log_full(level, ...) log_full_errno(level, 0, __VA_ARGS__)
+
+/* Normal logging */
 #define log_debug(...)     log_full(LOG_DEBUG,   __VA_ARGS__)
 #define log_info(...)      log_full(LOG_INFO,    __VA_ARGS__)
 #define log_notice(...)    log_full(LOG_NOTICE,  __VA_ARGS__)
@@ -160,18 +171,28 @@ do { \
 #define log_error(...)     log_full(LOG_ERR,     __VA_ARGS__)
 #define log_emergency(...) log_full(getpid() == 1 ? LOG_EMERG : LOG_ERR, __VA_ARGS__)
 
+/* Logging triggered by an errno-like error */
+#define log_debug_errno(error, ...)     log_full_errno(LOG_DEBUG,   error, __VA_ARGS__)
+#define log_info_errno(error, ...)      log_full_errno(LOG_INFO,    error, __VA_ARGS__)
+#define log_notice_errno(error, ...)    log_full_errno(LOG_NOTICE,  error, __VA_ARGS__)
+#define log_warning_errno(error, ...)   log_full_errno(LOG_WARNING, error, __VA_ARGS__)
+#define log_error_errno(error, ...)     log_full_errno(LOG_ERR,     error, __VA_ARGS__)
+#define log_emergency_errno(error, ...) log_full_errno(getpid() == 1 ? LOG_EMERG : LOG_ERR, __VA_ARGS__)
+
 #ifdef LOG_TRACE
 #  define log_trace(...) log_debug(__VA_ARGS__)
 #else
 #  define log_trace(...) do {} while(0)
 #endif
 
-#define log_struct(level, ...) log_struct_internal(level, __FILE__, __LINE__, __func__, __VA_ARGS__)
-
-#define log_oom() log_oom_internal(__FILE__, __LINE__, __func__)
+/* Structured logging */
+#define log_struct(level, ...) log_struct_internal(level, 0, __FILE__, __LINE__, __func__, __VA_ARGS__)
+#define log_struct_errno(level, error, ...) log_struct_internal(level, error, __FILE__, __LINE__, __func__, __VA_ARGS__)
 
 /* This modifies the buffer passed! */
-#define log_dump(level, buffer) log_dump_internal(level, __FILE__, __LINE__, __func__, buffer)
+#define log_dump(level, buffer) log_dump_internal(level, 0, __FILE__, __LINE__, __func__, buffer)
+
+#define log_oom() log_oom_internal(__FILE__, __LINE__, __func__)
 
 bool log_on_console(void) _pure_;