Bump version in Debian changelog.

CHANGELOG

@@ -1,3 +1,11 @@
+version 2.74
+            Fix reversion in 2.73 where --conf-file would attempt to
+	    read the default file, rather than no file.
+
+	    Fix inotify code to handle dangling symlinks better and
+	    not SEGV in some circumstances.
+
+
 version 2.73
             Fix crash at startup when an empty suffix is supplied to
 	    --conf-dir, also trivial memory leak. Thanks to 

debian/changelog

@@ -1,3 +1,15 @@
+dnsmasq (2.74-1) unstable; urgency=low
+
+   * New upstream. 
+	
+ -- Simon Kelley <simon@thekelleys.org.uk>  Thu, 7 Jul 2015 21:54:11 +0000
+
+dnsmasq (2.73-2) unstable; urgency=low
+
+   * Fix behaviour of empty --conf-file (closes: #790341)
+
+ -- Simon Kelley <simon@thekelleys.org.uk>  Thu, 7 Jul 2015 21:46:42 +0000
+
 dnsmasq (2.73-1) unstable; urgency=low
 
    * New upstream. (closes: #786996)

man/dnsmasq.8

@@ -654,7 +654,7 @@ Provide DS records to act a trust anchors for DNSSEC
 validation. Typically these will be the DS record(s) for Zone Signing
 key(s) of the root zone,
 but trust anchors for limited domains are also possible. The current
-root-zone trust anchors may be donwloaded from https://data.iana.org/root-anchors/root-anchors.xml 
+root-zone trust anchors may be downloaded from https://data.iana.org/root-anchors/root-anchors.xml 
 .TP
 .B --dnssec-check-unsigned
 As a default, dnsmasq does not check that unsigned DNS replies are

src/dnsmasq.c

@@ -1755,14 +1755,22 @@ int icmp_ping(struct in_addr addr)
      better not use any resources our caller has in use...)
      but we remain deaf to signals or further DHCP packets. */
 
-  int fd;
+  /* There can be a problem using dnsmasq_time() to end the loop, since
+     it's not monotonic, and can go backwards if the system clock is
+     tweaked, leading to the code getting stuck in this loop and
+     ignoring DHCP requests. To fix this, we check to see if select returned
+     as a result of a timeout rather than a socket becoming available. We
+     only allow this to happen as many times as it takes to get to the wait time
+     in quarter-second chunks. This provides a fallback way to end loop. */ 
+
+  int fd, rc;
   struct sockaddr_in saddr;
   struct { 
     struct ip ip;
     struct icmp icmp;
   } packet;
   unsigned short id = rand16();
-  unsigned int i, j;
+  unsigned int i, j, timeout_count;
   int gotreply = 0;
   time_t start, now;
 
@@ -1794,8 +1802,8 @@ int icmp_ping(struct in_addr addr)
   while (retry_send(sendto(fd, (char *)&packet.icmp, sizeof(struct icmp), 0, 
 			   (struct sockaddr *)&saddr, sizeof(saddr))));
   
-  for (now = start = dnsmasq_time(); 
-       difftime(now, start) < (float)PING_WAIT;)
+  for (now = start = dnsmasq_time(), timeout_count = 0; 
+       (difftime(now, start) < (float)PING_WAIT) && (timeout_count < PING_WAIT * 4);)
     {
       struct timeval tv;
       fd_set rset, wset;
@@ -1820,11 +1828,15 @@ int icmp_ping(struct in_addr addr)
 	}
 #endif
       
-      if (select(maxfd+1, &rset, &wset, NULL, &tv) < 0)
+      rc = select(maxfd+1, &rset, &wset, NULL, &tv);
+      
+      if (rc < 0)
 	{
 	  FD_ZERO(&rset);
 	  FD_ZERO(&wset);
 	}
+      else if (rc == 0)
+	timeout_count++;
 
       now = dnsmasq_time();
 

src/inotify.c

@@ -18,6 +18,7 @@
 #ifdef HAVE_INOTIFY
 
 #include <sys/inotify.h>
+#include <sys/param.h> /* For MAXSYMLINKS */
 
 /* the strategy is to set a inotify on the directories containing
    resolv files, for any files in the directory which are close-write 
@@ -35,10 +36,56 @@
 static char *inotify_buffer;
 #define INOTIFY_SZ (sizeof(struct inotify_event) + NAME_MAX + 1)
 
+/* If path is a symbolic link, return the path it
+   points to, made absolute if relative.
+   If path doesn't exist or is not a symlink, return NULL.
+   Return value is malloc'ed */
+static char *my_readlink(char *path)
+{
+  ssize_t rc;
+  size_t size = 64;
+  char *buf;
+
+  while (1)
+    {
+      buf = safe_malloc(size);
+      rc = readlink(path, buf, size);
+      
+      if (rc == -1)
+	{
+	  /* Not link or doesn't exist. */
+	  if (errno == EINVAL || errno == ENOENT)
+	    return NULL;
+	  else
+	    die(_("cannot access path %s: %s"), path, EC_MISC);
+	}
+      else if (rc < size-1)
+	{
+	  char *d;
+	  
+	  buf[rc] = 0;
+	  if (buf[0] != '/' && ((d = strrchr(path, '/'))))
+	    {
+	      /* Add path to relative link */
+	      char *new_buf = safe_malloc((d - path) + strlen(buf) + 2);
+	      *(d+1) = 0;
+	      strcpy(new_buf, path);
+	      strcat(new_buf, buf);
+	      free(buf);
+	      buf = new_buf;
+	    }
+	  return buf;
+	}
+
+      /* Buffer too small, increase and retry */
+      size += 64;
+      free(buf);
+    }
+}
+
 void inotify_dnsmasq_init()
 {
   struct resolvc *res;
-
   inotify_buffer = safe_malloc(INOTIFY_SZ);
   daemon->inotifyfd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
   
@@ -47,19 +94,22 @@ void inotify_dnsmasq_init()
   
   for (res = daemon->resolv_files; res; res = res->next)
     {
-      char *d = NULL, *path;
-      
-      if (!(path = realpath(res->name, NULL)))
+      char *d, *new_path, *path = safe_malloc(strlen(res->name) + 1);
+      int links = MAXSYMLINKS;
+
+      strcpy(path, res->name);
+
+      /* Follow symlinks until we reach a non-symlink, or a non-existant file. */
+      while ((new_path = my_readlink(path)))
 	{
-	  /* realpath will fail if the file doesn't exist, but
-	     dnsmasq copes with missing files, so fall back 
-	     and assume that symlinks are not in use in that case. */
-	  if (errno == ENOENT)
-	    path = res->name;
-	  else
-	    die(_("cannot cannonicalise resolv-file %s: %s"), res->name, EC_MISC); 
+	  if (links-- == 0)
+	    die(_("too many symlinks following %s"), res->name, EC_MISC);
+	  free(path);
+	  path = new_path;
 	}
-      
+
+      res->wd = -1;
+
       if ((d = strrchr(path, '/')))
 	{
 	  *d = 0; /* make path just directory */
@@ -70,10 +120,11 @@ void inotify_dnsmasq_init()
 	  
 	  if (res->wd == -1 && errno == ENOENT)
 	    die(_("directory %s for resolv-file is missing, cannot poll"), res->name, EC_MISC);
-	  
-	  if (res->wd == -1)
-	    die(_("failed to create inotify for %s: %s"), res->name, EC_MISC);
-	}
+	}	  
+	 
+      if (res->wd == -1)
+	die(_("failed to create inotify for %s: %s"), res->name, EC_MISC);
+	
     }
 }
 

src/option.c

@@ -4371,7 +4371,7 @@ void read_opts(int argc, char **argv, char *compile_opts)
 {
   char *buff = opt_malloc(MAXDNAME);
   int option, conffile_opt = '7', testmode = 0;
-  char *arg, *conffile = NULL;
+  char *arg, *conffile = CONFFILE;
       
   opterr = 0;
 
@@ -4488,11 +4488,8 @@ void read_opts(int argc, char **argv, char *compile_opts)
   if (conffile)
     {
       one_file(conffile, conffile_opt);
-      free(conffile);
-    }
-  else
-    {
-      one_file(CONFFILE, conffile_opt);
+      if (conffile_opt == 0)
+	free(conffile);
     }
 
   /* port might not be known when the address is parsed - fill in here */