On Fri, Jul 12, 2013 at 08:13:21PM +0100, Al Viro wrote:
> > Using O_DIRECTORY when we don't want to open a directory, and omitting
> > O_CREAT when we do want to create something new, is somewhat
> > counter-intuitive, but I think this would solve the problem with old
> > kernels.
>
> Hrm... I can't say I like it, but it's almost OK; the only problem here
> is the bug fixed by commit bc77daa78 - on some of the old kernels (including
> 3.10, BTW) we used to allow opening /proc/self/fd/0 with O_DIRECTORY|O_RDWR ;-/
>
> Said that, I think it's more tolerable than the kludge I came up with -
> one would need to pass it a procfs symlink as argument to hit that.
> Linus, your opinion?
I mean something like this:
Safer ABI for O_TMPFILE
[suggested by Rasmus Villemoes] make O_DIRECTORY | O_RDWR part of O_TMPFILE;
that will fail on old kernels in a lot more cases than what I came up with.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
diff --git a/arch/alpha/include/uapi/asm/fcntl.h b/arch/alpha/include/uapi/asm/fcntl.h
index dfdadb0..09f49a6 100644
--- a/arch/alpha/include/uapi/asm/fcntl.h
+++ b/arch/alpha/include/uapi/asm/fcntl.h
@@ -32,7 +32,7 @@
#define O_SYNC (__O_SYNC|O_DSYNC)
#define O_PATH 040000000
-#define O_TMPFILE 0100000000
+#define __O_TMPFILE 0100000000
#define F_GETLK 7
#define F_SETLK 8
diff --git a/arch/parisc/include/uapi/asm/fcntl.h b/arch/parisc/include/uapi/asm/fcntl.h
index cc61c47..34a46cb 100644
--- a/arch/parisc/include/uapi/asm/fcntl.h
+++ b/arch/parisc/include/uapi/asm/fcntl.h
@@ -20,7 +20,7 @@
#define O_INVISIBLE 004000000 /* invisible I/O, for DMAPI/XDSM */
#define O_PATH 020000000
-#define O_TMPFILE 040000000
+#define __O_TMPFILE 040000000
#define F_GETLK64 8
#define F_SETLK64 9
diff --git a/arch/sparc/include/uapi/asm/fcntl.h b/arch/sparc/include/uapi/asm/fcntl.h
index d73e5e0..7e8ace5 100644
--- a/arch/sparc/include/uapi/asm/fcntl.h
+++ b/arch/sparc/include/uapi/asm/fcntl.h
@@ -35,7 +35,7 @@
#define O_SYNC (__O_SYNC|O_DSYNC)
#define O_PATH 0x1000000
-#define O_TMPFILE 0x2000000
+#define __O_TMPFILE 0x2000000
#define F_GETOWN 5 /* for sockets. */
#define F_SETOWN 6 /* for sockets. */
diff --git a/fs/namei.c b/fs/namei.c
index b2beee7..8b61d10 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2977,7 +2977,7 @@ static struct file *path_openat(int dfd, struct filename *pathname,
file->f_flags = op->open_flag;
- if (unlikely(file->f_flags & O_TMPFILE)) {
+ if (unlikely(file->f_flags & __O_TMPFILE)) {
error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened);
goto out;
}
diff --git a/fs/open.c b/fs/open.c
index fca72c4..2a7d4ee 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -840,8 +840,8 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
if (flags & __O_SYNC)
flags |= O_DSYNC;
- if (flags & O_TMPFILE) {
- if (!(flags & O_CREAT))
+ if (flags & __O_TMPFILE) {
+ if ((flags & O_TMPFILE) != O_TMPFILE)
return -EINVAL;
acc_mode = MAY_OPEN | ACC_MODE(flags);
} else if (flags & O_PATH) {
diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h
index 06632be..9b19c49 100644
--- a/include/uapi/asm-generic/fcntl.h
+++ b/include/uapi/asm-generic/fcntl.h
@@ -84,10 +84,13 @@
#define O_PATH 010000000
#endif
-#ifndef O_TMPFILE
-#define O_TMPFILE 020000000
+#ifndef __O_TMPFILE
+#define __O_TMPFILE 020000000
#endif
+/* a horrid kludge trying to make sure that this will fail on old kernels */
+#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY | O_RDWR)
+
#ifndef O_NDELAY
#define O_NDELAY O_NONBLOCK
#endif
--
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