logger: check xgethostname() return value

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index fccd39cd1e83b46a1aa1d7510775d465c2a3674f..5af24469d2b51966718c323c8dceeaf92b2359a0 100644 (file)
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -343,9 +343,10 @@ static void write_output(const struct logger_ctl *ctl, const char *const msg)
                fprintf(stderr, "%s\n", buf);
 }
 
+#define NILVALUE "-"
 static void syslog_rfc3164_header(struct logger_ctl *const ctl)
 {
-       char pid[30], *hostname, *dot;
+       char pid[30], *hostname;
 
        *pid = '\0';
        if (ctl->fd < 0)
@@ -353,10 +354,12 @@ static void syslog_rfc3164_header(struct logger_ctl *const ctl)
        if (ctl->pid)
                snprintf(pid, sizeof(pid), "[%d]", ctl->pid);
 
-       hostname = xgethostname();
-       dot = strchr(hostname, '.');
-       if (dot)
-               *dot = '\0';
+       if ((hostname = xgethostname())) {
+               char *dot = strchr(hostname, '.');
+               if (dot)
+                       *dot = '\0';
+       } else
+               hostname = xstrdup(NILVALUE);
 
        xasprintf(&ctl->hdr, "<%d>%.15s %s %.200s%s: ",
                 ctl->pri, rfc3164_current_time(), hostname, ctl->tag, pid);
@@ -384,7 +387,6 @@ static void syslog_rfc3164_header(struct logger_ctl *const ctl)
  * specified RFC5424. The rest of the field mappings should be
  * pretty clear from RFC5424. -- Rainer Gerhards, 2015-03-10
  */
-#define NILVALUE "-"
 static void syslog_rfc5424_header(struct logger_ctl *const ctl)
 {
        char *time;
@@ -417,7 +419,8 @@ static void syslog_rfc5424_header(struct logger_ctl *const ctl)
                time = xstrdup(NILVALUE);
 
        if (ctl->rfc5424_host) {
-               hostname = xgethostname();
+               if (!(hostname = xgethostname()))
+                       hostname = xstrdup(NILVALUE);
                /* Arbitrary looking 'if (var < strlen()) checks originate from
                 * RFC 5424 - 6 Syslog Message Format definition.  */
                if (255 < strlen(hostname))