switch do_filp_open() to struct open_flags

take calculation of open_flags by open(2) arguments into new helper
in fs/open.c, move filp_open() over there, have it and do_sys_open()
use that helper, switch exec.c callers of do_filp_open() to explicit
(and constant) struct open_flags.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 101 insertions, 86 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 52a447d9b6a..ba99e1abb1a 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -115,13 +115,16 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
 	struct file *file;
 	char *tmp = getname(library);
 	int error = PTR_ERR(tmp);
+	static const struct open_flags uselib_flags = {
+		.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+		.acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN,
+		.intent = LOOKUP_OPEN
+	};
 
 	if (IS_ERR(tmp))
 		goto out;
 
-	file = do_filp_open(AT_FDCWD, tmp,
-				O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 0,
-				MAY_READ | MAY_EXEC | MAY_OPEN);
+	file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW);
 	putname(tmp);
 	error = PTR_ERR(file);
 	if (IS_ERR(file))
@@ -721,10 +724,13 @@ struct file *open_exec(const char *name)
 {
 	struct file *file;
 	int err;
+	static const struct open_flags open_exec_flags = {
+		.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+		.acc_mode = MAY_EXEC | MAY_OPEN,
+		.intent = LOOKUP_OPEN
+	};
 
-	file = do_filp_open(AT_FDCWD, name,
-				O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 0,
-				MAY_EXEC | MAY_OPEN);
+	file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW);
 	if (IS_ERR(file))
 		goto out;
 
diff --git a/fs/internal.h b/fs/internal.h
index 9b976b57d7f..6fdbdf2c604 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -106,6 +106,14 @@ extern void put_super(struct super_block *sb);
 struct nameidata;
 extern struct file *nameidata_to_filp(struct nameidata *);
 extern void release_open_intent(struct nameidata *);
+struct open_flags {
+	int open_flag;
+	int mode;
+	int acc_mode;
+	int intent;
+};
+extern struct file *do_filp_open(int dfd, const char *pathname,
+		const struct open_flags *op, int lookup_flags);
 
 /*
  * inode.c
diff --git a/fs/namei.c b/fs/namei.c
index 5e4206f4537..9c7fa946abe 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2169,13 +2169,6 @@ exit:
 	return ERR_PTR(error);
 }
 
-struct open_flags {
-	int open_flag;
-	int mode;
-	int acc_mode;
-	int intent;
-};
-
 /*
  * Handle O_CREAT case for do_filp_open
  */
@@ -2305,74 +2298,28 @@ exit:
  * open_to_namei_flags() for more details.
  */
 struct file *do_filp_open(int dfd, const char *pathname,
-		int open_flag, int mode, int acc_mode)
+		const struct open_flags *op, int flags)
 {
 	struct file *filp;
 	struct nameidata nd;
 	int error;
 	struct path path;
 	int count = 0;
-	int flag = open_to_namei_flags(open_flag);
-	int flags = 0;
-	struct open_flags op;
-
-	if (!(open_flag & O_CREAT))
-		mode = 0;
-
-	/* Must never be set by userspace */
-	open_flag &= ~FMODE_NONOTIFY;
-
-	/*
-	 * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
-	 * check for O_DSYNC if the need any syncing at all we enforce it's
-	 * always set instead of having to deal with possibly weird behaviour
-	 * for malicious applications setting only __O_SYNC.
-	 */
-	if (open_flag & __O_SYNC)
-		open_flag |= O_DSYNC;
-
-	op.open_flag = open_flag;
-
-	if (!acc_mode)
-		acc_mode = MAY_OPEN | ACC_MODE(open_flag);
-
-	/* O_TRUNC implies we need access checks for write permissions */
-	if (open_flag & O_TRUNC)
-		acc_mode |= MAY_WRITE;
-
-	/* Allow the LSM permission hook to distinguish append 
-	   access from general write access. */
-	if (open_flag & O_APPEND)
-		acc_mode |= MAY_APPEND;
-
-	op.acc_mode = acc_mode;
-
-	op.intent = LOOKUP_OPEN;
-	if (open_flag & O_CREAT) {
-		op.intent |= LOOKUP_CREATE;
-		if (open_flag & O_EXCL)
-			op.intent |= LOOKUP_EXCL;
-	}
-
-	if (open_flag & O_DIRECTORY)
-		flags |= LOOKUP_DIRECTORY;
-	if (!(open_flag & O_NOFOLLOW))
-		flags |= LOOKUP_FOLLOW;
 
 	filp = get_empty_filp();
 	if (!filp)
 		return ERR_PTR(-ENFILE);
 
-	filp->f_flags = open_flag;
+	filp->f_flags = op->open_flag;
 	nd.intent.open.file = filp;
-	nd.intent.open.flags = flag;
-	nd.intent.open.create_mode = mode;
+	nd.intent.open.flags = open_to_namei_flags(op->open_flag);
+	nd.intent.open.create_mode = op->mode;
 
-	if (open_flag & O_CREAT)
+	if (op->open_flag & O_CREAT)
 		goto creat;
 
 	/* !O_CREAT, simple open */
-	error = do_path_lookup(dfd, pathname, flags | op.intent, &nd);
+	error = do_path_lookup(dfd, pathname, flags | op->intent, &nd);
 	if (unlikely(error))
 		goto out_filp2;
 	error = -ELOOP;
@@ -2386,7 +2333,7 @@ struct file *do_filp_open(int dfd, const char *pathname,
 			goto out_path2;
 	}
 	audit_inode(pathname, nd.path.dentry);
-	filp = finish_open(&nd, open_flag, acc_mode);
+	filp = finish_open(&nd, op->open_flag, op->acc_mode);
 out2:
 	release_open_intent(&nd);
 	return filp;
@@ -2416,7 +2363,7 @@ reval:
 	/*
 	 * We have the parent and last component.
 	 */
-	filp = do_last(&nd, &path, &op, pathname);
+	filp = do_last(&nd, &path, op, pathname);
 	while (unlikely(!filp)) { /* trailing symlink */
 		struct path link = path;
 		struct inode *linki = link.dentry->d_inode;
@@ -2443,7 +2390,7 @@ reval:
 		if (unlikely(error))
 			filp = ERR_PTR(error);
 		else
-			filp = do_last(&nd, &path, &op, pathname);
+			filp = do_last(&nd, &path, op, pathname);
 		if (!IS_ERR(cookie) && linki->i_op->put_link)
 			linki->i_op->put_link(link.dentry, &nd, cookie);
 		path_put(&link);
@@ -2466,23 +2413,6 @@ out_filp:
 }
 
 /**
- * filp_open - open file and return file pointer
- *
- * @filename:	path to open
- * @flags:	open flags as per the open(2) second argument
- * @mode:	mode for the new file if O_CREAT is set, else ignored
- *
- * This is the helper to open a file from kernelspace if you really
- * have to.  But in generally you should not do this, so please move
- * along, nothing to see here..
- */
-struct file *filp_open(const char *filename, int flags, int mode)
-{
-	return do_filp_open(AT_FDCWD, filename, flags, mode, 0);
-}
-EXPORT_SYMBOL(filp_open);
-
-/**
  * lookup_create - lookup a dentry, creating it if it doesn't exist
  * @nd: nameidata info
  * @is_dir: directory flag
diff --git a/fs/open.c b/fs/open.c
index b47aab39c05..d05e18c60ba 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -890,15 +890,86 @@ void fd_install(unsigned int fd, struct file *file)
 
 EXPORT_SYMBOL(fd_install);
 
+static inline int build_open_flags(int flags, int mode, struct open_flags *op)
+{
+	int lookup_flags = 0;
+	int acc_mode;
+
+	if (!(flags & O_CREAT))
+		mode = 0;
+	op->mode = mode;
+
+	/* Must never be set by userspace */
+	flags &= ~FMODE_NONOTIFY;
+
+	/*
+	 * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
+	 * check for O_DSYNC if the need any syncing at all we enforce it's
+	 * always set instead of having to deal with possibly weird behaviour
+	 * for malicious applications setting only __O_SYNC.
+	 */
+	if (flags & __O_SYNC)
+		flags |= O_DSYNC;
+
+	op->open_flag = flags;
+
+	acc_mode = MAY_OPEN | ACC_MODE(flags);
+
+	/* O_TRUNC implies we need access checks for write permissions */
+	if (flags & O_TRUNC)
+		acc_mode |= MAY_WRITE;
+
+	/* Allow the LSM permission hook to distinguish append
+	   access from general write access. */
+	if (flags & O_APPEND)
+		acc_mode |= MAY_APPEND;
+
+	op->acc_mode = acc_mode;
+
+	op->intent = LOOKUP_OPEN;
+	if (flags & O_CREAT) {
+		op->intent |= LOOKUP_CREATE;
+		if (flags & O_EXCL)
+			op->intent |= LOOKUP_EXCL;
+	}
+
+	if (flags & O_DIRECTORY)
+		lookup_flags |= LOOKUP_DIRECTORY;
+	if (!(flags & O_NOFOLLOW))
+		lookup_flags |= LOOKUP_FOLLOW;
+	return lookup_flags;
+}
+
+/**
+ * filp_open - open file and return file pointer
+ *
+ * @filename:	path to open
+ * @flags:	open flags as per the open(2) second argument
+ * @mode:	mode for the new file if O_CREAT is set, else ignored
+ *
+ * This is the helper to open a file from kernelspace if you really
+ * have to.  But in generally you should not do this, so please move
+ * along, nothing to see here..
+ */
+struct file *filp_open(const char *filename, int flags, int mode)
+{
+	struct open_flags op;
+	int lookup = build_open_flags(flags, mode, &op);
+	return do_filp_open(AT_FDCWD, filename, &op, lookup);
+}
+EXPORT_SYMBOL(filp_open);
+
 long do_sys_open(int dfd, const char __user *filename, int flags, int mode)
 {
+	struct open_flags op;
+	int lookup = build_open_flags(flags, mode, &op);
 	char *tmp = getname(filename);
 	int fd = PTR_ERR(tmp);
 
 	if (!IS_ERR(tmp)) {
 		fd = get_unused_fd_flags(flags);
 		if (fd >= 0) {
-			struct file *f = do_filp_open(dfd, tmp, flags, mode, 0);
+			struct file *f = do_filp_open(dfd, tmp, &op, lookup);
 			if (IS_ERR(f)) {
 				put_unused_fd(fd);
 				fd = PTR_ERR(f);