override_cred->cap_permitted;
}
+ /*
+ * The new set of credentials can *only* be used in
+ * task-synchronous circumstances, and does not need
+ * RCU freeing, unless somebody then takes a separate
+ * reference to it.
+ *
+ * NOTE! This is _only_ true because this credential
+ * is used purely for override_creds() that installs
+ * it as the subjective cred. Other threads will be
+ * accessing ->real_cred, not the subjective cred.
+ *
+ * If somebody _does_ make a copy of this (using the
+ * 'get_current_cred()' function), that will clear the
+ * non_rcu field, because now that other user may be
+ * expecting RCU freeing. But normal thread-synchronous
+ * cred accesses will keep things non-RCY.
+ */
+ override_cred->non_rcu = 1;
+
old_cred = override_creds(override_cred);
retry:
res = user_path_at(dfd, filename, lookup_flags, &path);
int vfs_open(const struct path *path, struct file *file,
const struct cred *cred)
{
- struct dentry *dentry = path->dentry;
- struct inode *inode = dentry->d_inode;
+ struct inode *inode = vfs_select_inode(path->dentry, file->f_flags);
- file->f_path = *path;
- if (dentry->d_flags & DCACHE_OP_SELECT_INODE) {
- inode = dentry->d_op->d_select_inode(dentry, file->f_flags);
- if (IS_ERR(inode))
- return PTR_ERR(inode);
- }
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+ file->f_path = *path;
return do_dentry_open(file, inode, NULL, cred);
}
int lookup_flags = 0;
int acc_mode;
+ /*
+ * Clear out all open flags we don't know about so that we don't report
+ * them in fcntl(F_GETFD) or similar interfaces.
+ */
+ flags &= VALID_OPEN_FLAGS;
+
if (flags & (O_CREAT | __O_TMPFILE))
op->mode = (mode & S_IALLUGO) | S_IFREG;
else
EXPORT_SYMBOL(filp_open);
struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
- const char *filename, int flags)
+ const char *filename, int flags, umode_t mode)
{
struct open_flags op;
- int err = build_open_flags(flags, 0, &op);
+ int err = build_open_flags(flags, mode, &op);
if (err)
return ERR_PTR(err);
- if (flags & O_CREAT)
- return ERR_PTR(-EINVAL);
return do_file_open_root(dentry, mnt, filename, &op);
}
EXPORT_SYMBOL(file_open_root);
}
EXPORT_SYMBOL(nonseekable_open);
+
+/*
+ * stream_open is used by subsystems that want stream-like file descriptors.
+ * Such file descriptors are not seekable and don't have notion of position
+ * (file.f_pos is always 0). Contrary to file descriptors of other regular
+ * files, .read() and .write() can run simultaneously.
+ *
+ * stream_open never fails and is marked to return int so that it could be
+ * directly used as file_operations.open .
+ */
+int stream_open(struct inode *inode, struct file *filp)
+{
+ filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
+ filp->f_mode |= FMODE_STREAM;
+ return 0;
+}
+
+EXPORT_SYMBOL(stream_open);