agent,common: move get_socket_name() into common.

* agent/gpg-agent.c (get_socket_name): move to ...
* common/sysutils.c (gnupg_get_socket_name): ... here.

--
This allows us to use the same functionality in dirmngr as well.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>

1 files changed, 49 insertions, 0 deletions

diff --git a/common/sysutils.c b/common/sysutils.c
index 60483ac36..71200a604 100644
--- a/common/sysutils.c
+++ b/common/sysutils.c
@@ -62,6 +62,9 @@
 #  include <winsock2.h>
 # endif
 # include <windows.h>
+#else /*!HAVE_W32_SYSTEM*/
+# include <sys/socket.h>
+# include <sys/un.h>
 #endif
 #ifdef HAVE_INOTIFY_INIT
 # include <sys/inotify.h>
@@ -1090,3 +1093,49 @@ gnupg_inotify_has_name (int fd, const char *name)
 
   return 0; /* Not found.  */
 }
+
+
+/* Return a malloc'ed string that is the path to the passed
+ * unix-domain socket (or return NULL if this is not a valid
+ * unix-domain socket).  We use a plain int here because it is only
+ * used on Linux.
+ *
+ * FIXME: This function needs to be moved to libassuan.  */
+#ifndef HAVE_W32_SYSTEM
+char *
+gnupg_get_socket_name (int fd)
+{
+  struct sockaddr_un un;
+  socklen_t len = sizeof(un);
+  char *name = NULL;
+
+  if (getsockname (fd, (struct sockaddr*)&un, &len) != 0)
+    log_error ("could not getsockname(%d): %s\n", fd,
+               gpg_strerror (gpg_error_from_syserror ()));
+  else if (un.sun_family != AF_UNIX)
+    log_error ("file descriptor %d is not a unix-domain socket\n", fd);
+  else if (len <= offsetof (struct sockaddr_un, sun_path))
+    log_error ("socket name not present for file descriptor %d\n", fd);
+  else if (len > sizeof(un))
+    log_error ("socket name for file descriptor %d was truncated "
+               "(passed %zu bytes, wanted %u)\n", fd, sizeof(un), len);
+  else
+    {
+      size_t namelen = len - offsetof (struct sockaddr_un, sun_path);
+
+      log_debug ("file descriptor %d has path %s (%zu octets)\n", fd,
+                 un.sun_path, namelen);
+      name = xtrymalloc (namelen + 1);
+      if (!name)
+        log_error ("failed to allocate memory for name of fd %d: %s\n",
+                   fd, gpg_strerror (gpg_error_from_syserror ()));
+      else
+        {
+          memcpy (name, un.sun_path, namelen);
+          name[namelen] = 0;
+        }
+    }
+
+  return name;
+}
+#endif /*!HAVE_W32_SYSTEM*/