core: Check for GPG_TTY as well as DISPLAY.

* src/engine-assuan.c (llass_new): Update --ttyname from GPG_TTY.
* src/engine-g13.c (g13_new): Ditto.
* src/engine-gpg.c (gpg_new): Ditto.
* src/engine-uiserver.c (uiserver_new): Ditto.
* src/engine-gpgsm.c (gpgsm_new): Ditto.

--
Useful when no DISPLAY is set and there is no attached terminal to the
current process.

Signed-off-by: Ben Kibbey <bjk@luxsci.net>

src/engine-assuan.c

@@ -219,6 +219,7 @@ llass_new (void **engine, const char *file_name, const char *home_dir,
   gpgme_error_t err = 0;
   engine_llass_t llass;
   char *optstr;
+  char *env_tty = NULL;
 
   (void)version; /* Not yet used.  */
 
@@ -280,13 +281,24 @@ llass_new (void **engine, const char *file_name, const char *home_dir,
         }
     }
 
-  if (llass->opt.gpg_agent && isatty (1))
+  if (llass->opt.gpg_agent)
+    err = _gpgme_getenv ("GPG_TTY", &env_tty);
+
+  if (llass->opt.gpg_agent && (isatty (1) || env_tty || err))
     {
-      int rc;
+      int rc = 0;
       char dft_ttyname[64];
       char *dft_ttytype = NULL;
 
-      rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
+      if (err)
+        goto leave;
+      else if (env_tty)
+        {
+          snprintf (dft_ttyname, sizeof (dft_ttyname), "%s", env_tty);
+          free (env_tty);
+        }
+      else
+        rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
 
       /* Even though isatty() returns 1, ttyname_r() may fail in many
 	 ways, e.g., when /dev/pts is not accessible under chroot.  */

src/engine-g13.c

@@ -222,6 +222,7 @@ g13_new (void **engine, const char *file_name, const char *home_dir,
   const char *argv[5];
   char *dft_display = NULL;
   char dft_ttyname[64];
+  char *env_tty = NULL;
   char *dft_ttytype = NULL;
   char *optstr;
 
@@ -284,11 +285,20 @@ g13_new (void **engine, const char *file_name, const char *home_dir,
 	goto leave;
     }
 
-  if (isatty (1))
+  err = _gpgme_getenv ("GPG_TTY", &env_tty);
+  if (isatty (1) || env_tty || err)
     {
-      int rc;
+      int rc = 0;
 
-      rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
+      if (err)
+        goto leave;
+      else if (env_tty)
+        {
+          snprintf (dft_ttyname, sizeof (dft_ttyname), "%s", env_tty);
+          free (env_tty);
+        }
+      else
+        rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
 
       /* Even though isatty() returns 1, ttyname_r() may fail in many
 	 ways, e.g., when /dev/pts is not accessible under chroot.  */

src/engine-gpg.c

@@ -454,6 +454,7 @@ gpg_new (void **engine, const char *file_name, const char *home_dir,
   char *dft_display = NULL;
   char dft_ttyname[64];
   char *dft_ttytype = NULL;
+  char *env_tty = NULL;
 
   gpg = calloc (1, sizeof *gpg);
   if (!gpg)
@@ -560,11 +561,20 @@ gpg_new (void **engine, const char *file_name, const char *home_dir,
 	goto leave;
     }
 
-  if (isatty (1))
+  rc = _gpgme_getenv ("GPG_TTY", &env_tty);
+  if (isatty (1) || env_tty || rc)
     {
-      int err;
+      int err = 0;
 
-      err = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
+      if (rc)
+        goto leave;
+      else if (env_tty)
+        {
+          snprintf (dft_ttyname, sizeof (dft_ttyname), "%s", env_tty);
+          free (env_tty);
+        }
+      else
+        err = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
 
       /* Even though isatty() returns 1, ttyname_r() may fail in many
 	 ways, e.g., when /dev/pts is not accessible under chroot.  */

src/engine-gpgsm.c

@@ -253,6 +253,7 @@ gpgsm_new (void **engine, const char *file_name, const char *home_dir,
 #endif
   char *dft_display = NULL;
   char dft_ttyname[64];
+  char *env_tty = NULL;
   char *dft_ttytype = NULL;
   char *optstr;
 
@@ -410,11 +411,20 @@ gpgsm_new (void **engine, const char *file_name, const char *home_dir,
 	goto leave;
     }
 
-  if (isatty (1))
+  err = _gpgme_getenv ("GPG_TTY", &env_tty);
+  if (isatty (1) || env_tty || err)
     {
-      int rc;
+      int rc = 0;
 
-      rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
+      if (err)
+        goto leave;
+      else if (env_tty)
+        {
+          snprintf (dft_ttyname, sizeof (dft_ttyname), "%s", env_tty);
+          free (env_tty);
+        }
+      else
+        rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
 
       /* Even though isatty() returns 1, ttyname_r() may fail in many
 	 ways, e.g., when /dev/pts is not accessible under chroot.  */

src/engine-uiserver.c

@@ -248,6 +248,7 @@ uiserver_new (void **engine, const char *file_name, const char *home_dir,
   engine_uiserver_t uiserver;
   char *dft_display = NULL;
   char dft_ttyname[64];
+  char *env_tty = NULL;
   char *dft_ttytype = NULL;
   char *optstr;
 
@@ -330,11 +331,20 @@ uiserver_new (void **engine, const char *file_name, const char *home_dir,
 	goto leave;
     }
 
-  if (isatty (1))
+  err = _gpgme_getenv ("GPG_TTY", &env_tty);
+  if (isatty (1) || env_tty || err)
     {
-      int rc;
+      int rc = 0;
 
-      rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
+      if (err)
+        goto leave;
+      else if (env_tty)
+        {
+          snprintf (dft_ttyname, sizeof (dft_ttyname), "%s", env_tty);
+          free (env_tty);
+        }
+      else
+        rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
 
       /* Even though isatty() returns 1, ttyname_r() may fail in many
 	 ways, e.g., when /dev/pts is not accessible under chroot.  */