util: add a bit of syntactic sugar for saving/restoring errno

[elogind.git] / src / shared / log.c

diff --git a/src/shared/log.c b/src/shared/log.c
index 8d3458e7311dbb0f293725985b32f3a49c85df98..0dd04bc51e65e73519cbaee52ddff58e6e415fdf 100644 (file)
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -441,6 +441,37 @@ 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) {
+        snprintf(header, size,
+                 "PRIORITY=%i\n"
+                 "SYSLOG_FACILITY=%i\n"
+                 "%s%.*s%s"
+                 "%s%.*i%s"
+                 "%s%.*s%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" : "",
+                 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" : "",
+                 program_invocation_short_name);
+        header[size - 1] = '\0';
+        return 0;
+}
+
 static int write_to_journal(
         int level,
         const char*file,
@@ -451,39 +482,20 @@ static int write_to_journal(
         const char *buffer) {
 
         char header[LINE_MAX];
-        struct iovec iovec[3];
-        struct msghdr mh;
+        struct iovec iovec[4] = {{0}};
+        struct msghdr mh = {0};
 
         if (journal_fd < 0)
                 return 0;
 
-        snprintf(header, sizeof(header),
-                 "PRIORITY=%i\n"
-                 "SYSLOG_FACILITY=%i\n"
-                 "CODE_FILE=%s\n"
-                 "CODE_LINE=%i\n"
-                 "CODE_FUNCTION=%s\n"
-                 "%s%.*s%s"
-                 "SYSLOG_IDENTIFIER=%s\n"
-                 "MESSAGE=",
-                 LOG_PRI(level),
-                 LOG_FAC(level),
-                 file,
-                 line,
-                 func,
-                 object ? object_name : "",
-                 object ? LINE_MAX : 0, object, /* %.0s means no output */
-                 object ? "\n" : "",
-                 program_invocation_short_name);
+        log_do_header(header, sizeof(header), level,
+                      file, line, func, object_name, object);
 
-        char_array_0(header);
-
-        zero(iovec);
         IOVEC_SET_STRING(iovec[0], header);
-        IOVEC_SET_STRING(iovec[1], buffer);
-        IOVEC_SET_STRING(iovec[2], "\n");
+        IOVEC_SET_STRING(iovec[1], "MESSAGE=");
+        IOVEC_SET_STRING(iovec[2], buffer);
+        IOVEC_SET_STRING(iovec[3], "\n");
 
-        zero(mh);
         mh.msg_iov = iovec;
         mh.msg_iovlen = ELEMENTSOF(iovec);
 
@@ -586,18 +598,14 @@ int log_dump_internal(
         const char *func,
         char *buffer) {
 
-        int saved_errno, r;
+        PROTECT_ERRNO;
 
         /* This modifies the buffer... */
 
         if (_likely_(LOG_PRI(level) > log_max_level))
                 return 0;
 
-        saved_errno = errno;
-        r = log_dispatch(level, file, line, func, NULL, NULL, buffer);
-        errno = saved_errno;
-
-        return r;
+        return log_dispatch(level, file, line, func, NULL, NULL, buffer);
 }
 
 int log_metav(
@@ -608,20 +616,16 @@ int log_metav(
         const char *format,
         va_list ap) {
 
+        PROTECT_ERRNO;
         char buffer[LINE_MAX];
-        int saved_errno, r;
 
         if (_likely_(LOG_PRI(level) > log_max_level))
                 return 0;
 
-        saved_errno = errno;
         vsnprintf(buffer, sizeof(buffer), format, ap);
         char_array_0(buffer);
 
-        r = log_dispatch(level, file, line, func, NULL, NULL, buffer);
-        errno = saved_errno;
-
-        return r;
+        return log_dispatch(level, file, line, func, NULL, NULL, buffer);
 }
 
 int log_meta(
@@ -651,21 +655,17 @@ int log_metav_object(
         const char *format,
         va_list ap) {
 
+        PROTECT_ERRNO;
         char buffer[LINE_MAX];
-        int saved_errno, r;
 
         if (_likely_(LOG_PRI(level) > log_max_level))
                 return 0;
 
-        saved_errno = errno;
         vsnprintf(buffer, sizeof(buffer), format, ap);
         char_array_0(buffer);
 
-        r = log_dispatch(level, file, line, func,
-                         object_name, object, buffer);
-        errno = saved_errno;
-
-        return r;
+        return log_dispatch(level, file, line, func,
+                            object_name, object, buffer);
 }
 
 int log_meta_object(
@@ -723,7 +723,7 @@ int log_struct_internal(
                 const char *func,
                 const char *format, ...) {
 
-        int saved_errno;
+        PROTECT_ERRNO;
         va_list ap;
         int r;
 
@@ -736,37 +736,20 @@ int log_struct_internal(
         if ((level & LOG_FACMASK) == 0)
                 level = log_facility | LOG_PRI(level);
 
-        saved_errno = errno;
-
         if ((log_target == LOG_TARGET_AUTO ||
              log_target == LOG_TARGET_JOURNAL_OR_KMSG ||
              log_target == LOG_TARGET_JOURNAL) &&
             journal_fd >= 0) {
 
                 char header[LINE_MAX];
-                struct iovec iovec[17];
+                struct iovec iovec[17] = {{0}};
                 unsigned n = 0, i;
                 struct msghdr mh;
-                const char nl = '\n';
+                static const char nl = '\n';
 
                 /* If the journal is available do structured logging */
-
-                snprintf(header, sizeof(header),
-                        "PRIORITY=%i\n"
-                        "SYSLOG_FACILITY=%i\n"
-                        "CODE_FILE=%s\n"
-                        "CODE_LINE=%i\n"
-                        "CODE_FUNCTION=%s\n"
-                        "SYSLOG_IDENTIFIER=%s\n",
-                        LOG_PRI(level),
-                        LOG_FAC(level),
-                        file,
-                        line,
-                        func,
-                        program_invocation_short_name);
-                char_array_0(header);
-
-                zero(iovec);
+                log_do_header(header, sizeof(header), level,
+                              file, line, func, NULL, NULL);
                 IOVEC_SET_STRING(iovec[n++], header);
 
                 va_start(ap, format);
@@ -846,7 +829,6 @@ int log_struct_internal(
                         r = -EINVAL;
         }
 
-        errno = saved_errno;
         return r;
 }