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>

5 files changed, 101 insertions, 88 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 52a447d9b6ab..ba99e1abb1aa 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 9b976b57d7fe..6fdbdf2c6047 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 5e4206f45371..9c7fa946abe1 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 b47aab39c057..d05e18c60bae 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);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e38b50a4b9d2..9c75714f92c1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2205,8 +2205,6 @@ extern struct file *create_read_pipe(struct file *f, int flags);
 extern struct file *create_write_pipe(int flags);
 extern void free_write_pipe(struct file *);
 
-extern struct file *do_filp_open(int dfd, const char *pathname,
-                int open_flag, int mode, int acc_mode);
 extern int may_open(struct path *, int, int);
 
 extern int kernel_read(struct file *, loff_t, char *, unsigned long);