agetty: simplify code in dolog() preprocessor blocks

Aim is to make dolog() a lot more readable and understandable, with downside
of when (rarely?) USE_SYSLOG it not defined the function will use a bit more
space from stack.  I think that is price well worth paying.

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

diff --git a/term-utils/agetty.c b/term-utils/agetty.c
index 96bf41b36764dd5a511ffa690c78dfaa5a9808d3..703fb9fd76fa67a5735b637ea149136cc7494ab6 100644 (file)
--- a/term-utils/agetty.c
+++ b/term-utils/agetty.c
@@ -2391,46 +2391,40 @@ static void list_speeds(void)
  * Will be used by log_err() and log_warn() therefore
  * it takes a format as well as va_list.
  */
-#define        str2cpy(b,s1,s2)        strcat(strcpy(b,s1),s2)
-
-static void dolog(int priority, const char *fmt, va_list ap)
-{
-#ifndef        USE_SYSLOG
-       int fd;
+static void dolog(int priority
+#ifndef USE_SYSLOG
+                 __attribute__((__unused__))
 #endif
-       char buf[BUFSIZ];
-       char *bp;
-
+                 , const char *fmt, va_list ap)
+{
+#ifdef USE_SYSLOG
        /*
         * If the diagnostic is reported via syslog(3), the process name is
         * automatically prepended to the message. If we write directly to
         * /dev/console, we must prepend the process name ourselves.
         */
-#ifdef USE_SYSLOG
-       buf[0] = '\0';
-       bp = buf;
-#else
-       str2cpy(buf, program_invocation_short_name, ": ");
-       bp = buf + strlen(buf);
-#endif                         /* USE_SYSLOG */
-       vsnprintf(bp, sizeof(buf)-strlen(buf), fmt, ap);
-
-       /*
-        * Write the diagnostic directly to /dev/console if we do not use the
-        * syslog(3) facility.
-        */
-#ifdef USE_SYSLOG
        openlog(program_invocation_short_name, LOG_PID, LOG_AUTHPRIV);
-       syslog(priority, "%s", buf);
+       vsyslog(priority, fmt, ap);
        closelog();
 #else
+       /*
+        * Write the diagnostic directly to /dev/console if we do not use
+        * the syslog(3) facility.
+        */
+       char buf[BUFSIZ];
+       char new_fmt[BUFSIZ];
+       int fd;
+
+       snprintf(new_fmt, sizeof(new_fmt), "%s: %s\r\n",
+                program_invocation_short_name, fmt);
        /* Terminate with CR-LF since the console mode is unknown. */
-       strcat(bp, "\r\n");
+       vsnprintf(buf, sizeof(buf), new_fmt, ap);
+
        if ((fd = open("/dev/console", 1)) >= 0) {
                write_all(fd, buf, strlen(buf));
                close(fd);
        }
-#endif                         /* USE_SYSLOG */
+#endif /* USE_SYSLOG */
 }
 
 static void exit_slowly(int code)