logger: use iovec for all message

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index 9878c8229e23d3240db3c2de993a7587a64fe9e3..d5683b69130f2f4cd90c02ecb6574ce170353fce 100644 (file)
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -402,6 +402,22 @@ static const char *rfc3164_current_time(void)
        return time;
 }
 
+#define next_iovec(ary, idx) __extension__ ({          \
+               assert(ARRAY_SIZE(ary) > idx);  \
+               assert(idx >= 0);                       \
+               &ary[idx++];                            \
+})
+
+#define iovec_add_string(ary, idx, str, len)           \
+       do {                                            \
+               struct iovec *v = next_iovec(ary, idx); \
+               v->iov_base = (void *) str;             \
+               v->iov_len = len ? len : strlen(str);   \
+       } while (0)
+
+#define iovec_memcmp(ary, idx, str, len)               \
+               memcmp((ary)[(idx) - 1].iov_base, str, len)
+
 /* writes generated buffer to desired destination. For TCP syslog,
  * we use RFC6587 octet-stuffing (unless octet-counting is selected).
  * This is not great, but doing full blown RFC5425 (TLS) looks like
@@ -410,26 +426,28 @@ static const char *rfc3164_current_time(void)
  */
 static void write_output(const struct logger_ctl *ctl, const char *const msg)
 {
-       char *buf;
-       const size_t len = ctl->octet_count ?
-               xasprintf(&buf, "%zu %s%s", strlen(ctl->hdr)+strlen(msg), ctl->hdr, msg):
-               xasprintf(&buf, "%s%s", ctl->hdr, msg);
+       struct iovec iov[4];
+       int iovlen = 0;
+       char *octet = NULL;
+
+       /* 1) octen count */
+       if (ctl->octet_count) {
+               size_t len = xasprintf(&octet, "%zu ", strlen(ctl->hdr) + strlen(msg));
+               iovec_add_string(iov, iovlen, octet, len);
+       }
+
+       /* 2) header */
+       iovec_add_string(iov, iovlen, ctl->hdr, 0);
+
+       /* 3) message */
+       iovec_add_string(iov, iovlen, msg, 0);
 
        if (!ctl->noact) {
                struct msghdr msg = { 0 };
-               struct iovec iov[2];
-               size_t iovlen = 0;
-
-               iov[0].iov_base = buf;
-               iov[0].iov_len = len;
-               iovlen++;
-
-               /* add extra \n to make sure message is terminated */
-               if ((ctl->socket_type == TYPE_TCP) && !ctl->octet_count) {
-                       iov[1].iov_base = "\n";
-                       iov[1].iov_len = 1;
-                       iovlen++;
-               }
+
+               /* 4) add extra \n to make sure message is terminated */
+               if ((ctl->socket_type == TYPE_TCP) && !ctl->octet_count)
+                       iovec_add_string(iov, iovlen, "\n", 1);
 
                msg.msg_iov = iov;
                msg.msg_iovlen = iovlen;
@@ -437,9 +455,16 @@ static void write_output(const struct logger_ctl *ctl, const char *const msg)
                if (sendmsg(ctl->fd, &msg, 0) < 0)
                        warn(_("send message failed"));
        }
-       if (ctl->stderr_printout)
-               fprintf(stderr, "%s\n", buf);
-       free(buf);
+
+       if (ctl->stderr_printout) {
+               /* make sure it's terminated for stderr */
+               if (iovec_memcmp(iov, iovlen, "\n", 1) != 0)
+                       iovec_add_string(iov, iovlen, "\n", 1);
+
+               ignore_result( writev(STDERR_FILENO, iov, iovlen) );
+       }
+
+       free(octet);
 }
 
 #define NILVALUE "-"