Changes in uspace/lib/posix/fcntl.c [f00af83:4cf8ca6] in mainline

File:

• uspace/lib/posix/fcntl.c (modified) (1 diff)

uspace/lib/posix/fcntl.c

@@ -52 +52 @@
 int posix_fcntl(int fd, int cmd, ...)
 {
+        int rc;
         int flags;
 
         switch (cmd) {
         case F_DUPFD:
-        case F_DUPFD_CLOEXEC:
-                /* VFS currently does not provide the functionality to duplicate
-                 * opened file descriptor. */
-                // FIXME: implement this once dup() is available
-                errno = ENOTSUP;
-                return -1;
+        case F_DUPFD_CLOEXEC: /* FD_CLOEXEC is not supported. */
+                /* VFS does not provide means to express constraints on the new
+                 * file descriptor so the third argument is ignored. */
+
+                /* Retrieve node triplet corresponding to the file descriptor. */
+                /* Empty statement after label. */;
+                fdi_node_t node;
+                rc = fd_node(fd, &node);
+                if (rc != EOK) {
+                        errno = -rc;
+                        return -1;
+                }
+
+                /* Reopen the node so the fresh file descriptor is generated. */
+                int newfd = open_node(&node, 0);
+                if (newfd < 0) {
+                        errno = -newfd;
+                        return -1;
+                }
+
+                /* Associate the newly generated descriptor to the file description
+                 * of the old file descriptor. Just reopened node will be automatically
+                 * closed. */
+                rc = dup2(fd, newfd);
+                if (rc != EOK) {
+                        errno = -rc;
+                        return -1;
+                }
+
+                return newfd;
         case F_GETFD:
                 /* FD_CLOEXEC is not supported. There are no other flags. */