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");

4 files changed, 179 insertions, 120 deletions

diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c
index 027c49ce3b..6bd9d9ebf7 100644
--- a/src/shared/conf-parser.c
+++ b/src/shared/conf-parser.c
@@ -38,10 +38,16 @@
 #include "exit-status.h"
 #include "sd-messages.h"
 
-int log_syntax_internal(const char *unit, int level,
-                        const char *file, unsigned line, const char *func,
-                        const char *config_file, unsigned config_line,
-                        int error, const char *format, ...) {
+int log_syntax_internal(
+                const char *unit,
+                int level,
+                const char *file,
+                int line,
+                const char *func,
+                const char *config_file,
+                unsigned config_line,
+                int error,
+                const char *format, ...) {
 
         _cleanup_free_ char *msg = NULL;
         int r;
@@ -55,21 +61,21 @@ int log_syntax_internal(const char *unit, int level,
 
         if (unit)
                 r = log_struct_internal(level,
+                                        error > 0 ? error : EINVAL,
                                         file, line, func,
                                         getpid() == 1 ? "UNIT=%s" : "USER_UNIT=%s", unit,
                                         MESSAGE_ID(SD_MESSAGE_CONFIG_ERROR),
                                         "CONFIG_FILE=%s", config_file,
                                         "CONFIG_LINE=%u", config_line,
-                                        "ERRNO=%d", error > 0 ? error : EINVAL,
                                         "MESSAGE=[%s:%u] %s", config_file, config_line, msg,
                                         NULL);
         else
                 r = log_struct_internal(level,
+                                        error > 0 ? error : EINVAL,
                                         file, line, func,
                                         MESSAGE_ID(SD_MESSAGE_CONFIG_ERROR),
                                         "CONFIG_FILE=%s", config_file,
                                         "CONFIG_LINE=%u", config_line,
-                                        "ERRNO=%d", error > 0 ? error : EINVAL,
                                         "MESSAGE=[%s:%u] %s", config_file, config_line, msg,
                                         NULL);
 
diff --git a/src/shared/conf-parser.h b/src/shared/conf-parser.h
index 69d32711b7..2507a44444 100644
--- a/src/shared/conf-parser.h
+++ b/src/shared/conf-parser.h
@@ -119,10 +119,16 @@ int config_parse_mode(const char *unit, const char *filename, unsigned line, con
 int config_parse_log_facility(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_log_level(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 
-int log_syntax_internal(const char *unit, int level,
-                        const char *file, unsigned line, const char *func,
-                        const char *config_file, unsigned config_line,
-                        int error, const char *format, ...) _printf_(9, 10);
+int log_syntax_internal(
+                const char *unit,
+                int level,
+                const char *file,
+                int line,
+                const char *func,
+                const char *config_file,
+                unsigned config_line,
+                int error,
+                const char *format, ...) _printf_(9, 10);
 
 #define log_syntax(unit, level, config_file, config_line, error, ...)   \
         log_syntax_internal(unit, level,                                \
diff --git a/src/shared/log.c b/src/shared/log.c
index d465311d02..ba959b914e 100644
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -122,7 +122,7 @@ static int create_log_socket(int type) {
                 timeval_store(&tv, 10 * USEC_PER_MSEC);
         else
                 timeval_store(&tv, 10 * USEC_PER_SEC);
-        (void)setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+        (void) setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
 
         return fd;
 }
@@ -302,10 +302,11 @@ void log_set_facility(int facility) {
 
 static int write_to_console(
                 int level,
+                int error,
                 const char*file,
                 int line,
                 const char *func,
-                const char *object_name,
+                const char *object_field,
                 const char *object,
                 const char *buffer) {
 
@@ -356,13 +357,14 @@ static int write_to_console(
 }
 
 static int write_to_syslog(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *object_name,
-        const char *object,
-        const char *buffer) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *object_field,
+                const char *object,
+                const char *buffer) {
 
         char header_priority[16], header_time[64], header_pid[16];
         struct iovec iovec[5] = {};
@@ -418,13 +420,14 @@ static int write_to_syslog(
 }
 
 static int write_to_kmsg(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *object_name,
-        const char *object,
-        const char *buffer) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *object_field,
+                const char *object,
+                const char *buffer) {
 
         char header_priority[16], header_pid[16];
         struct iovec iovec[5] = {};
@@ -450,45 +453,55 @@ static int write_to_kmsg(
         return 1;
 }
 
-static int log_do_header(char *header, size_t size,
-                         int level,
-                         const char *file, int line, const char *func,
-                         const char *object_name, const char *object) {
+static int log_do_header(
+                char *header,
+                size_t size,
+                int level,
+                int error,
+                const char *file, int line, const char *func,
+                const char *object_field, const char *object) {
+
         snprintf(header, size,
                  "PRIORITY=%i\n"
                  "SYSLOG_FACILITY=%i\n"
-                 "%s%.*s%s"
+                 "%s%s%s"
                  "%s%.*i%s"
-                 "%s%.*s%s"
-                 "%s%.*s%s"
+                 "%s%s%s"
+                 "%s%.*i%s"
+                 "%s%s%s"
                  "SYSLOG_IDENTIFIER=%s\n",
                  LOG_PRI(level),
                  LOG_FAC(level),
-                 file ? "CODE_FILE=" : "",
-                 file ? LINE_MAX : 0, file, /* %.0s means no output */
-                 file ? "\n" : "",
+                 isempty(file) ? "" : "CODE_FILE=",
+                 isempty(file) ? "" : file,
+                 isempty(file) ? "" : "\n",
                  line ? "CODE_LINE=" : "",
                  line ? 1 : 0, line, /* %.0d means no output too, special case for 0 */
                  line ? "\n" : "",
-                 func ? "CODE_FUNCTION=" : "",
-                 func ? LINE_MAX : 0, func,
-                 func ? "\n" : "",
-                 object ? object_name : "",
-                 object ? LINE_MAX : 0, object, /* %.0s means no output */
-                 object ? "\n" : "",
+                 isempty(func) ? "" : "CODE_FUNCTION=",
+                 isempty(func) ? "" : func,
+                 isempty(func) ? "" : "\n",
+                 error ? "ERRNO=" : "",
+                 error ? 1 : 0, error,
+                 error ? "\n" : "",
+                 isempty(object) ? "" : object_field,
+                 isempty(object) ? "" : object,
+                 isempty(object) ? "" : "\n",
                  program_invocation_short_name);
         header[size - 1] = '\0';
+
         return 0;
 }
 
 static int write_to_journal(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *object_name,
-        const char *object,
-        const char *buffer) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *object_field,
+                const char *object,
+                const char *buffer) {
 
         char header[LINE_MAX];
         struct iovec iovec[4] = {};
@@ -497,8 +510,7 @@ static int write_to_journal(
         if (journal_fd < 0)
                 return 0;
 
-        log_do_header(header, sizeof(header), level,
-                      file, line, func, object_name, object);
+        log_do_header(header, sizeof(header), level, error, file, line, func, object_field, object);
 
         IOVEC_SET_STRING(iovec[0], header);
         IOVEC_SET_STRING(iovec[1], "MESSAGE=");
@@ -515,13 +527,14 @@ static int write_to_journal(
 }
 
 static int log_dispatch(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *object_name,
-        const char *object,
-        char *buffer) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *object_field,
+                const char *object,
+                char *buffer) {
 
         int r = 0;
 
@@ -548,8 +561,7 @@ static int log_dispatch(
                     log_target == LOG_TARGET_JOURNAL_OR_KMSG ||
                     log_target == LOG_TARGET_JOURNAL) {
 
-                        k = write_to_journal(level, file, line, func,
-                                             object_name, object, buffer);
+                        k = write_to_journal(level, error, file, line, func, object_field, object, buffer);
                         if (k < 0) {
                                 if (k != -EAGAIN)
                                         log_close_journal();
@@ -561,8 +573,7 @@ static int log_dispatch(
                 if (log_target == LOG_TARGET_SYSLOG_OR_KMSG ||
                     log_target == LOG_TARGET_SYSLOG) {
 
-                        k = write_to_syslog(level, file, line, func,
-                                            object_name, object, buffer);
+                        k = write_to_syslog(level, error, file, line, func, object_field, object, buffer);
                         if (k < 0) {
                                 if (k != -EAGAIN)
                                         log_close_syslog();
@@ -578,8 +589,7 @@ static int log_dispatch(
                      log_target == LOG_TARGET_JOURNAL_OR_KMSG ||
                      log_target == LOG_TARGET_KMSG)) {
 
-                        k = write_to_kmsg(level, file, line, func,
-                                          object_name, object, buffer);
+                        k = write_to_kmsg(level, error, file, line, func, object_field, object, buffer);
                         if (k < 0) {
                                 log_close_kmsg();
                                 log_open_console();
@@ -588,8 +598,7 @@ static int log_dispatch(
                 }
 
                 if (k <= 0) {
-                        k = write_to_console(level, file, line, func,
-                                             object_name, object, buffer);
+                        k = write_to_console(level, error, file, line, func, object_field, object, buffer);
                         if (k < 0)
                                 return k;
                 }
@@ -602,6 +611,7 @@ static int log_dispatch(
 
 int log_dump_internal(
         int level,
+        int error,
         const char*file,
         int line,
         const char *func,
@@ -614,16 +624,17 @@ int log_dump_internal(
         if (_likely_(LOG_PRI(level) > log_max_level))
                 return 0;
 
-        return log_dispatch(level, file, line, func, NULL, NULL, buffer);
+        return log_dispatch(level, error, file, line, func, NULL, NULL, buffer);
 }
 
 int log_metav(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *format,
-        va_list ap) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *format,
+                va_list ap) {
 
         PROTECT_ERRNO;
         char buffer[LINE_MAX];
@@ -631,38 +642,44 @@ int log_metav(
         if (_likely_(LOG_PRI(level) > log_max_level))
                 return 0;
 
+        /* Make sure that %m maps to the specified error */
+        if (error != 0)
+                errno = error;
+
         vsnprintf(buffer, sizeof(buffer), format, ap);
         char_array_0(buffer);
 
-        return log_dispatch(level, file, line, func, NULL, NULL, buffer);
+        return log_dispatch(level, error, file, line, func, NULL, NULL, buffer);
 }
 
 int log_meta(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *format, ...) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *format, ...) {
 
         int r;
         va_list ap;
 
         va_start(ap, format);
-        r = log_metav(level, file, line, func, format, ap);
+        r = log_metav(level, error, file, line, func, format, ap);
         va_end(ap);
 
         return r;
 }
 
 int log_metav_object(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *object_name,
-        const char *object,
-        const char *format,
-        va_list ap) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *object_field,
+                const char *object,
+                const char *format,
+                va_list ap) {
 
         PROTECT_ERRNO;
         char buffer[LINE_MAX];
@@ -670,34 +687,44 @@ int log_metav_object(
         if (_likely_(LOG_PRI(level) > log_max_level))
                 return 0;
 
+        /* Make sure that %m maps to the specified error */
+        if (error != 0)
+                errno = error;
+
         vsnprintf(buffer, sizeof(buffer), format, ap);
         char_array_0(buffer);
 
-        return log_dispatch(level, file, line, func,
-                            object_name, object, buffer);
+        return log_dispatch(level, error, file, line, func, object_field, object, buffer);
 }
 
 int log_meta_object(
-        int level,
-        const char*file,
-        int line,
-        const char *func,
-        const char *object_name,
-        const char *object,
-        const char *format, ...) {
+                int level,
+                int error,
+                const char*file,
+                int line,
+                const char *func,
+                const char *object_field,
+                const char *object,
+                const char *format, ...) {
 
         int r;
         va_list ap;
 
         va_start(ap, format);
-        r = log_metav_object(level, file, line, func,
-                             object_name, object, format, ap);
+        r = log_metav_object(level, error, file, line, func, object_field, object, format, ap);
         va_end(ap);
 
         return r;
 }
 
-static void log_assert(int level, const char *text, const char *file, int line, const char *func, const char *format) {
+static void log_assert(
+                int level,
+                const char *text,
+                const char *file,
+                int line,
+                const char *func,
+                const char *format) {
+
         static char buffer[LINE_MAX];
 
         if (_likely_(LOG_PRI(level) > log_max_level))
@@ -710,7 +737,7 @@ static void log_assert(int level, const char *text, const char *file, int line,
         char_array_0(buffer);
         log_abort_msg = buffer;
 
-        log_dispatch(level, file, line, func, NULL, NULL, buffer);
+        log_dispatch(level, 0, file, line, func, NULL, NULL, buffer);
 }
 
 noreturn void log_assert_failed(const char *text, const char *file, int line, const char *func) {
@@ -729,12 +756,13 @@ void log_assert_failed_return(const char *text, const char *file, int line, cons
 }
 
 int log_oom_internal(const char *file, int line, const char *func) {
-        log_meta(LOG_ERR, file, line, func, "Out of memory.");
+        log_meta(LOG_ERR, ENOMEM, file, line, func, "Out of memory.");
         return -ENOMEM;
 }
 
 int log_struct_internal(
                 int level,
+                int error,
                 const char *file,
                 int line,
                 const char *func,
@@ -767,8 +795,7 @@ int log_struct_internal(
                 static const char nl = '\n';
 
                 /* If the journal is available do structured logging */
-                log_do_header(header, sizeof(header), level,
-                              file, line, func, NULL, NULL);
+                log_do_header(header, sizeof(header), level, error, file, line, func, NULL, NULL);
                 IOVEC_SET_STRING(iovec[n++], header);
 
                 va_start(ap, format);
@@ -840,8 +867,7 @@ int log_struct_internal(
                 va_end(ap);
 
                 if (found)
-                        r = log_dispatch(level, file, line, func,
-                                         NULL, NULL, buf + 8);
+                        r = log_dispatch(level, error, file, line, func, NULL, NULL, buf + 8);
                 else
                         r = -EINVAL;
         }
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_;