common: Add a default socket name feature.

* common/logging.c (log_set_socket_dir_cb): New.
(socket_dir_cb): New.
(set_file_fd): Allow "socket://".
(fun_writer): Implement default socket name.
* common/init.c (_init_common_subsystems): Register default socket.
--

This change allows the use of

log-file socket://

in any configuration file.

Signed-off-by: Werner Koch <wk@gnupg.org>

common/init.c

@@ -222,6 +222,9 @@ _init_common_subsystems (gpg_err_source_t errsource, int *argcp, char ***argvp)
 
   /* --version et al shall use estream as well.  */
   argparse_register_outfnc (writestring_via_estream);
+
+  /* Logging shall use the standard socket directory as fallback.  */
+  log_set_socket_dir_cb (gnupg_socketdir);
 }
 
 

common/logging.c

@@ -104,6 +104,7 @@ static int with_pid;
 static int no_registry;
 #endif
 static int (*get_pid_suffix_cb)(unsigned long *r_value);
+static const char * (*socket_dir_cb)(void);
 static int running_detached;
 static int force_prefixes;
 
@@ -218,6 +219,7 @@ fun_writer (void *cookie_arg, const void *buffer, size_t size)
       struct sockaddr_in srvr_addr_in;
 #ifndef HAVE_W32_SYSTEM
       struct sockaddr_un srvr_addr_un;
+      const char *name_for_err = "";
 #endif
       size_t addrlen;
       struct sockaddr *srvr_addr = NULL;
@@ -237,23 +239,41 @@ fun_writer (void *cookie_arg, const void *buffer, size_t size)
           pf = PF_INET;
         }
 #ifndef HAVE_W32_SYSTEM
-      else if (!strncmp (name, "socket://", 9) && name[9])
+      else if (!strncmp (name, "socket://", 9))
         name += 9;
 #endif
 
       if (af == AF_LOCAL)
         {
-#ifdef HAVE_W32_SYSTEM
           addrlen = 0;
-#else
+#ifndef HAVE_W32_SYSTEM
           memset (&srvr_addr, 0, sizeof srvr_addr);
           srvr_addr_un.sun_family = af;
-          strncpy (srvr_addr_un.sun_path,
+          if (!*name && (name = socket_dir_cb ()) && *name)
-                   name, sizeof (srvr_addr_un.sun_path)-1);
+            {
-          srvr_addr_un.sun_path[sizeof (srvr_addr_un.sun_path)-1] = 0;
+              if (strlen (name) + 7 < sizeof (srvr_addr_un.sun_path)-1)
-          srvr_addr = (struct sockaddr *)&srvr_addr_un;
+                {
-          addrlen = SUN_LEN (&srvr_addr_un);
+                  strncpy (srvr_addr_un.sun_path,
-#endif
+                           name, sizeof (srvr_addr_un.sun_path)-1);
+                  strcat (srvr_addr_un.sun_path, "/S.log");
+                  srvr_addr_un.sun_path[sizeof (srvr_addr_un.sun_path)-1] = 0;
+                  srvr_addr = (struct sockaddr *)&srvr_addr_un;
+                  addrlen = SUN_LEN (&srvr_addr_un);
+                  name_for_err = srvr_addr_un.sun_path;
+                }
+            }
+          else
+            {
+              if (*name && strlen (name) < sizeof (srvr_addr_un.sun_path)-1)
+                {
+                  strncpy (srvr_addr_un.sun_path,
+                           name, sizeof (srvr_addr_un.sun_path)-1);
+                  srvr_addr_un.sun_path[sizeof (srvr_addr_un.sun_path)-1] = 0;
+                  srvr_addr = (struct sockaddr *)&srvr_addr_un;
+                  addrlen = SUN_LEN (&srvr_addr_un);
+                }
+            }
+#endif /*!HAVE_W32SYSTEM*/
         }
       else
         {
@@ -352,8 +372,8 @@ fun_writer (void *cookie_arg, const void *buffer, size_t size)
             {
               if (!cookie->quiet && !running_detached
                   && isatty (es_fileno (es_stderr)))
-                es_fprintf (es_stderr, "can't connect to '%s': %s\n",
+                es_fprintf (es_stderr, "can't connect to '%s%s': %s\n",
-                            cookie->name, strerror(errno));
+                            cookie->name, name_for_err, strerror(errno));
               sock_close (cookie->fd);
               cookie->fd = -1;
             }
@@ -462,7 +482,7 @@ set_file_fd (const char *name, int fd)
   if (name && !strncmp (name, "tcp://", 6) && name[6])
     want_socket = 1;
 #ifndef HAVE_W32_SYSTEM
-  else if (name && !strncmp (name, "socket://", 9) && name[9])
+  else if (name && !strncmp (name, "socket://", 9))
     want_socket = 2;
 #endif /*HAVE_W32_SYSTEM*/
 #ifdef HAVE_W32CE_SYSTEM
@@ -554,6 +574,15 @@ log_set_fd (int fd)
 }
 
 
+/* Set a function to retrieve the directory name of a socket if
+ * only "socket://" has been given to log_set_file.  */
+void
+log_set_socket_dir_cb (const char *(*fnc)(void))
+{
+  socket_dir_cb = fnc;
+}
+
+
 void
 log_set_pid_suffix_cb (int (*cb)(unsigned long *r_value))
 {

common/logging.h

@@ -42,6 +42,7 @@ int  log_get_errorcount (int clear);
 void log_inc_errorcount (void);
 void log_set_file( const char *name );
 void log_set_fd (int fd);
+void log_set_socket_dir_cb (const char *(*fnc)(void));
 void log_set_pid_suffix_cb (int (*cb)(unsigned long *r_value));
 void log_set_prefix (const char *text, unsigned int flags);
 const char *log_get_prefix (unsigned int *flags);

doc/dirmngr.texi

@@ -163,7 +163,8 @@ verbose commands to @sc{dirmngr}, such as @option{-vv}.
 @item --log-file @var{file}
 @opindex log-file
 Append all logging output to @var{file}.  This is very helpful in
-seeing what the agent actually does.
+seeing what the agent actually does.  Use @file{socket://} to log to
+socket.
 
 @item --debug-level @var{level}
 @opindex debug-level

doc/gpg-agent.texi

@@ -312,11 +312,12 @@ should in general not be used to avoid X-sniffing attacks.
 @item --log-file @var{file}
 @opindex log-file
 @efindex HKCU\Software\GNU\GnuPG:DefaultLogFile
-Append all logging output to @var{file}.  This is very helpful in seeing
+Append all logging output to @var{file}.  This is very helpful in
-what the agent actually does.  If neither a log file nor a log file
+seeing what the agent actually does. Use @file{socket://} to log to
-descriptor has been set on a Windows platform, the Registry entry
+socket.  If neither a log file nor a log file descriptor has been set
-@code{HKCU\Software\GNU\GnuPG:DefaultLogFile}, if set, is used to specify
+on a Windows platform, the Registry entry
-the logging output.
+@code{HKCU\Software\GNU\GnuPG:DefaultLogFile}, if set, is used to
+specify the logging output.
 
 
 @anchor{option --no-allow-mark-trusted}

doc/gpg.texi

@@ -2697,9 +2697,8 @@ Write log output to file descriptor @code{n} and not to STDERR.
 @item --log-file @code{file}
 @itemx --logger-file @code{file}
 @opindex log-file
-Same as @option{--logger-fd}, except the logger data is written to file
+Same as @option{--logger-fd}, except the logger data is written to
-@code{file}.  Note that @option{--log-file} is only implemented for
+file @code{file}.  Use @file{socket://} to log to socket.
-GnuPG-2.
 
 @item --attribute-fd @code{n}
 @opindex attribute-fd

doc/gpgsm.texi

@@ -384,6 +384,7 @@ Do not print a warning when the so called "secure memory" cannot be used.
 @item --log-file @var{file}
 @opindex log-file
 When running in server mode, append all logging output to @var{file}.
+Use @file{socket://} to log to socket.
 
 @end table
 

doc/scdaemon.texi

@@ -239,7 +239,8 @@ debugging.
 @item --log-file @var{file}
 @opindex log-file
 Append all logging output to @var{file}.  This is very helpful in
-seeing what the agent actually does.
+seeing what the agent actually does.  Use @file{socket://} to log to
+socket.
 
 
 @item --pcsc-driver @var{library}

doc/tools.texi

@@ -103,12 +103,14 @@ This waits for connections on the local socket
 @file{/home/foo/.gnupg/S.log} and shows all log entries.  To make this
 work the option @option{log-file} needs to be used with all modules
 which logs are to be shown.  The value for that option must be given
-with a special prefix (e.g. in the conf file):
+with a special prefix (e.g. in the conf files):
 
 @example
 log-file socket:///home/foo/.gnupg/S.log
 @end example
 
+If only @code{socket://} is used a default socket file named
+@file{S.log} in the standard socket directory is used.
 For debugging purposes it is also possible to do remote logging.  Take
 care if you use this feature because the information is send in the
 clear over the network.  Use this syntax in the conf files:
@@ -1737,8 +1739,8 @@ Try to be as quiet as possible.
 
 @item --log-file @var{file}
 @opindex log-file
-Append all logging output to @var{file}.  Default is to write logging
+Append all logging output to @var{file}.  Use @file{socket://} to log
-information to STDERR.
+to socket.  Default is to write logging information to STDERR.
 
 @end table