Add --log-debug option and MS_DEBUG flag to my_syslog().

man/dnsmasq.8

@@ -135,6 +135,9 @@ running, will go exclusively to the file.) When logging to a file,
 dnsmasq will close and reopen the file when it receives SIGUSR2. This 
 allows the log file to be rotated without stopping dnsmasq.
 .TP
+.B --log-debug
+Enable extra logging intended for debugging rather than information.
+.TP
 .B --log-async[=<lines>]
 Enable asynchronous logging and optionally set the limit on the
 number of lines

src/dnsmasq.h

@@ -269,7 +269,8 @@ struct event_desc {
 #define OPT_IGNORE_CLID    59
 #define OPT_SINGLE_PORT    60
 #define OPT_LEASE_RENEW    61
-#define OPT_LAST           62
+#define OPT_LOG_DEBUG      62
+#define OPT_LAST           63
 
 #define OPTION_BITS (sizeof(unsigned int)*8)
 #define OPTION_SIZE ( (OPT_LAST/OPTION_BITS)+((OPT_LAST%OPTION_BITS)!=0) )
@@ -277,11 +278,13 @@ struct event_desc {
 #define option_val(x) ((1u) << ((x) % OPTION_BITS))
 #define option_bool(x) (option_var(x) & option_val(x))
 
-/* extra flags for my_syslog, we use a couple of facilities since they are known 
-   not to occupy the same bits as priorities, no matter how syslog.h is set up. */
+/* extra flags for my_syslog, we use facilities since they are known 
+   not to occupy the same bits as priorities, no matter how syslog.h is set up. 
+   MS_DEBUG messages are suppressed unless --log-debug is set. */
 #define MS_TFTP   LOG_USER
 #define MS_DHCP   LOG_DAEMON
 #define MS_SCRIPT LOG_MAIL
+#define MS_DEBUG  LOG_NEWS
 
 /* Note that this is used widely as a container for IPv4/IPv6 addresses,
    so for that reason, was well as to avoid wasting memory in almost every

src/log.c

@@ -273,7 +273,7 @@ static void log_write(void)
 /* priority is one of LOG_DEBUG, LOG_INFO, LOG_NOTICE, etc. See sys/syslog.h.
    OR'd to priority can be MS_TFTP, MS_DHCP, ... to be able to do log separation between
    DNS, DHCP and TFTP services.
-*/
+   If OR'd with MS_DEBUG, the messages are suppressed unless --log-debug is set. */
 void my_syslog(int priority, const char *format, ...)
 {
   va_list ap;
@@ -290,6 +290,12 @@ void my_syslog(int priority, const char *format, ...)
     func = "-dhcp";
   else if ((LOG_FACMASK & priority) == MS_SCRIPT)
     func = "-script";
+  else if ((LOG_FACMASK & priority) == MS_DEBUG)
+    {
+      if (!option_bool(OPT_LOG_DEBUG))
+	return;
+      func = "-debug";
+    }
   
 #ifdef LOG_PRI
   priority = LOG_PRI(priority);

src/option.c

@@ -169,6 +169,7 @@ struct myoption {
 #define LOPT_SCRIPT_TIME   360
 #define LOPT_PXE_VENDOR    361
 #define LOPT_DYNHOST       362
+#define LOPT_LOG_DEBUG     363
  
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
@@ -343,6 +344,7 @@ static const struct myoption opts[] =
     { "dumpmask", 1, 0, LOPT_DUMPMASK },
     { "dhcp-ignore-clid", 0, 0,  LOPT_IGNORE_CLID },
     { "dynamic-host", 1, 0, LOPT_DYNHOST },
+    { "log-debug", 0, 0, LOPT_LOG_DEBUG },
     { NULL, 0, 0, 0 }
   };
 
@@ -515,6 +517,7 @@ static struct {
   { LOPT_QUIET_DHCP, OPT_QUIET_DHCP, NULL, gettext_noop("Do not log routine DHCP."), NULL },
   { LOPT_QUIET_DHCP6, OPT_QUIET_DHCP6, NULL, gettext_noop("Do not log routine DHCPv6."), NULL },
   { LOPT_QUIET_RA, OPT_QUIET_RA, NULL, gettext_noop("Do not log RA."), NULL },
+  { LOPT_LOG_DEBUG, OPT_LOG_DEBUG, NULL, gettext_noop("Log debugging information."), NULL }, 
   { LOPT_LOCAL_SERVICE, OPT_LOCAL_SERVICE, NULL, gettext_noop("Accept queries only from directly-connected networks."), NULL },
   { LOPT_LOOP_DETECT, OPT_LOOP_DETECT, NULL, gettext_noop("Detect and remove DNS forwarding loops."), NULL },
   { LOPT_IGNORE_ADDR, ARG_DUP, "<ipaddr>", gettext_noop("Ignore DNS responses containing ipaddr."), NULL },