Better explain why the connection fails

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

src/ctl.c

@@ -36,7 +36,7 @@ ctl_rundir(char *dst, size_t size)
             return dst;
     }
 
-    errno = EINTR;
+    errno = EPERM;
     return NULL;
 }
 
@@ -151,7 +151,7 @@ ctl_connect(const char *file)
 
     if (!file) {
         if (dp = opendir(dir), !dp)
-            return -1;
+            return CTL_ERROR_NONE;
 
         struct dirent *d = NULL;
 
@@ -197,3 +197,23 @@ ctl_connect(const char *file)
 
     return fd;
 }
+
+void
+ctl_explain_connect(int ret)
+{
+    switch (ret) {
+        case 0:
+            break;
+        case CTL_ERROR_MANY:
+            gt_log("please select a tunnel\n");
+            break;
+        case CTL_ERROR_NONE:
+            gt_log("no active tunnel\n");
+            break;
+        default:
+            gt_log("unknown error\n"); /* FALLTHRU */
+        case -1:
+            if (errno)
+                perror("connect");
+    }
+}

src/ctl.h

@@ -48,3 +48,5 @@ int   ctl_create  (const char *);
 int   ctl_connect (const char *);
 int   ctl_reply   (int, struct ctl_msg *, struct ctl_msg *);
 void  ctl_delete  (int);
+
+void ctl_explain_connect (int);

src/path.c

@@ -135,19 +135,7 @@ gt_path(int argc, char **argv)
     int fd = ctl_connect(dev);
 
     if (fd < 0) {
-        switch (fd) {
+        ctl_explain_connect(fd);
-        case -1:
-            perror("path");
-            break;
-        case CTL_ERROR_NONE:
-            gt_log("no device\n");
-            break;
-        case CTL_ERROR_MANY:
-            gt_log("please choose a device\n");
-            break;
-        default:
-            gt_log("couldn't connect\n");
-        }
         return 1;
     }
 

src/set.c

@@ -54,19 +54,7 @@ gt_set(int argc, char **argv)
     int fd = ctl_connect(dev);
 
     if (fd < 0) {
-        switch (fd) {
+        ctl_explain_connect(fd);
-        case -1:
-            perror("set");
-            break;
-        case CTL_ERROR_NONE:
-            gt_log("no device\n");
-            break;
-        case CTL_ERROR_MANY:
-            gt_log("please choose a device\n");
-            break;
-        default:
-            gt_log("couldn't connect\n");
-        }
         return 1;
     }
 

src/show.c

@@ -126,19 +126,7 @@ gt_show(int argc, char **argv)
     int fd = ctl_connect(dev);
 
     if (fd < 0) {
-        switch (fd) {
+        ctl_explain_connect(fd);
-        case -1:
-            perror("show");
-            break;
-        case CTL_ERROR_NONE:
-            gt_log("no device\n");
-            break;
-        case CTL_ERROR_MANY:
-            gt_log("please choose a device\n");
-            break;
-        default:
-            gt_log("couldn't connect\n");
-        }
         return 1;
     }