lib/9pfs: Return ENOTTY on terminal ioctl calls

Some applications (e.g. python) will use `ioctl()` calls to check if an
interactive interpretor should be started or if a file should be read.

`9pfs` should respond to all terminal-related calls with an `ENOTTY`
error, so applications know that they are not running in an interactive
environment.

In order to detect the ioctl request type, add a new macro,
`IOCTL_CMD_ISTYPE(cmd, type)`, which will check the corresponding bytes
from the request number (an enhanced version of the Linux `_IOC_TYPE`).

Signed-off-by: Stefan Jumarea <stefanjumarea02@gmail.com>
Reviewed-by: Sergiu Moga <sergiu@unikraft.io>
Approved-by: Simon Kuenzer <simon@unikraft.io>
GitHub-Closes: #1098

diff --git a/lib/9pfs/9pfs_vnops.c b/lib/9pfs/9pfs_vnops.c
index 127c3206c7e34b3dba3bdb4fbc837e5d28ba0d96..5768144b665d2f98b042c451775210f33078e620 100644 (file)
--- a/lib/9pfs/9pfs_vnops.c
+++ b/lib/9pfs/9pfs_vnops.c
@@ -1015,7 +1015,6 @@ static int uk_9pfs_symlink(struct vnode *dvp, const char *op, const char *np)
 static int uk_9pfs_ioctl(struct vnode *dvp, struct vfscore_file *fp,
                         unsigned long com, void *data)
 {
-       switch (com) {
        /**
         * HACK: In binary compatibility mode, Ruby tries to set O_ASYNC,
         * which Unikraft does not yet support. If the `ioctl` call returns
@@ -1028,12 +1027,15 @@ static int uk_9pfs_ioctl(struct vnode *dvp, struct vfscore_file *fp,
         * Setting `ioctl` to a nullop will not work, since it is used by
         * interpreted languages (e.g. python3) to check if it should start
         * the interpretor or just read a file.
+        *
+        * For every `ioctl` request related to a terminal, return ENOTTY.
         */
-       case FIONBIO:
+       if (com == FIONBIO)
                return 0;
-       default:
-               return ENOTSUP;
-       }
+       if (IOCTL_CMD_ISTYPE(com, IOCTL_CMD_TYPE_TTY))
+               return ENOTTY;
+
+       return ENOTSUP;
 }
 
 #define uk_9pfs_seek           ((vnop_seek_t)vfscore_vop_nullop)

diff --git a/lib/vfscore/include/vfscore/vnode.h b/lib/vfscore/include/vfscore/vnode.h
index d698912b3ae7d0aca9d877aff6ac5127e584ee13..871cf1b26d457e84dceb75cebba3e164788131eb 100644 (file)
--- a/lib/vfscore/include/vfscore/vnode.h
+++ b/lib/vfscore/include/vfscore/vnode.h
@@ -43,6 +43,15 @@
 #include <vfscore/uio.h>
 #include <vfscore/dentry.h>
 
+#define IOCTL_CMD_TYPE_SHIFT           (8)
+#define IOCTL_CMD_TYPE_MASK            (0xFF << IOCTL_CMD_TYPE_SHIFT)
+#define IOCTL_CMD_TYPE_TTY             ('T')
+
+#define IOCTL_CMD_ISTYPE(cmd, type)                    \
+               ((cmd & (IOCTL_CMD_TYPE_MASK)) ==       \
+                (((type) << IOCTL_CMD_TYPE_SHIFT) &    \
+                 IOCTL_CMD_TYPE_MASK))
+
 struct vfsops;
 struct vnops;
 struct vnode;