From d8a5ba45457e4a22aa39c939121efd7bb6c76672 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:26 -0700 Subject: [PATCH] FUSE - core This patch adds FUSE core. This contains the following files: o inode.c - superblock operations (alloc_inode, destroy_inode, read_inode, clear_inode, put_super, show_options) - registers FUSE filesystem o fuse_i.h - private header file Requirements ============ The most important difference between orinary filesystems and FUSE is the fact, that the filesystem data/metadata is provided by a userspace process run with the privileges of the mount "owner" instead of the kernel, or some remote entity usually running with elevated privileges. The security implication of this is that a non-privileged user must not be able to use this capability to compromise the system. Obvious requirements arising from this are: - mount owner should not be able to get elevated privileges with the help of the mounted filesystem - mount owner should not be able to induce undesired behavior in other users' or the super user's processes - mount owner should not get illegitimate access to information from other users' and the super user's processes These are currently ensured with the following constraints: 1) mount is only allowed to directory or file which the mount owner can modify without limitation (write access + no sticky bit for directories) 2) nosuid,nodev mount options are forced 3) any process running with fsuid different from the owner is denied all access to the filesystem 1) and 2) are ensured by the "fusermount" mount utility which is a setuid root application doing the actual mount operation. 3) is ensured by a check in the permission() method in kernel I started thinking about doing 3) in a different way because Christoph H. made a big deal out of it, saying that FUSE is unacceptable into mainline in this form. The suggested use of private namespaces would be OK, but in their current form have many limitations that make their use impractical (as discussed in this thread). Suggested improvements that would address these limitations: - implement shared subtrees - allow a process to join an existing namespace (make namespaces first-class objects) - implement the namespace creation/joining in a PAM module With all that in place the check of owner against current->fsuid may be removed from the FUSE kernel module, without compromising the security requirements. Suid programs still interesting questions, since they get access even to the private namespace causing some information leak (exact order/timing of filesystem operations performed), giving some ptrace-like capabilities to unprivileged users. BTW this problem is not strictly limited to the namespace approach, since suid programs setting fsuid and accessing users' files will succeed with the current approach too. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 include/linux/fuse.h (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h new file mode 100644 index 000000000000..2b1f4ae01e9d --- /dev/null +++ b/include/linux/fuse.h @@ -0,0 +1,38 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2005 Miklos Szeredi + + This program can be distributed under the terms of the GNU GPL. + See the file COPYING. +*/ + +/* This file defines the kernel interface of FUSE */ + +#include + +/** Version number of this interface */ +#define FUSE_KERNEL_VERSION 5 + +/** Minor version number of this interface */ +#define FUSE_KERNEL_MINOR_VERSION 1 + +/** The node ID of the root inode */ +#define FUSE_ROOT_ID 1 + +struct fuse_attr { + __u64 ino; + __u64 size; + __u64 blocks; + __u64 atime; + __u64 mtime; + __u64 ctime; + __u32 atimensec; + __u32 mtimensec; + __u32 ctimensec; + __u32 mode; + __u32 nlink; + __u32 uid; + __u32 gid; + __u32 rdev; +}; + -- cgit v1.2.3 From 334f485df85ac7736ebe14940bf0a059c5f26d7d Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:27 -0700 Subject: [PATCH] FUSE - device functions This adds the FUSE device handling functions. This contains the following files: o dev.c - fuse device operations (read, write, release, poll) - registers misc device - support for sending requests to userspace Signed-off-by: Miklos Szeredi Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index 2b1f4ae01e9d..a1aebd7104c4 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -11,7 +11,7 @@ #include /** Version number of this interface */ -#define FUSE_KERNEL_VERSION 5 +#define FUSE_KERNEL_VERSION 6 /** Minor version number of this interface */ #define FUSE_KERNEL_MINOR_VERSION 1 @@ -19,6 +19,12 @@ /** The node ID of the root inode */ #define FUSE_ROOT_ID 1 +/** The major number of the fuse character device */ +#define FUSE_MAJOR 10 + +/** The minor number of the fuse character device */ +#define FUSE_MINOR 229 + struct fuse_attr { __u64 ino; __u64 size; @@ -36,3 +42,31 @@ struct fuse_attr { __u32 rdev; }; +enum fuse_opcode { + FUSE_INIT = 26 +}; + +/* Conservative buffer size for the client */ +#define FUSE_MAX_IN 8192 + +struct fuse_init_in_out { + __u32 major; + __u32 minor; +}; + +struct fuse_in_header { + __u32 len; + __u32 opcode; + __u64 unique; + __u64 nodeid; + __u32 uid; + __u32 gid; + __u32 pid; +}; + +struct fuse_out_header { + __u32 len; + __s32 error; + __u64 unique; +}; + -- cgit v1.2.3 From e5e5558e923f35839108a12718494ecb73fb782f Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:28 -0700 Subject: [PATCH] FUSE - read-only operations This patch adds the read-only filesystem operations of FUSE. This contains the following files: o dir.c - directory, symlink and file-inode operations The following operations are added: o lookup o getattr o readlink o follow_link o directory open o readdir o directory release o permission o dentry revalidate o statfs Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index a1aebd7104c4..21b9ba16f8d5 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -42,13 +42,61 @@ struct fuse_attr { __u32 rdev; }; +struct fuse_kstatfs { + __u64 blocks; + __u64 bfree; + __u64 bavail; + __u64 files; + __u64 ffree; + __u32 bsize; + __u32 namelen; +}; + enum fuse_opcode { + FUSE_LOOKUP = 1, + FUSE_FORGET = 2, /* no reply */ + FUSE_GETATTR = 3, + FUSE_READLINK = 5, + FUSE_GETDIR = 7, + FUSE_STATFS = 17, FUSE_INIT = 26 }; /* Conservative buffer size for the client */ #define FUSE_MAX_IN 8192 +#define FUSE_NAME_MAX 1024 + +struct fuse_entry_out { + __u64 nodeid; /* Inode ID */ + __u64 generation; /* Inode generation: nodeid:gen must + be unique for the fs's lifetime */ + __u64 entry_valid; /* Cache timeout for the name */ + __u64 attr_valid; /* Cache timeout for the attributes */ + __u32 entry_valid_nsec; + __u32 attr_valid_nsec; + struct fuse_attr attr; +}; + +struct fuse_forget_in { + __u64 version; +}; + +struct fuse_attr_out { + __u64 attr_valid; /* Cache timeout for the attributes */ + __u32 attr_valid_nsec; + __u32 dummy; + struct fuse_attr attr; +}; + +struct fuse_getdir_out { + __u32 fd; +}; + +struct fuse_statfs_out { + struct fuse_kstatfs st; +}; + struct fuse_init_in_out { __u32 major; __u32 minor; @@ -70,3 +118,15 @@ struct fuse_out_header { __u64 unique; }; +struct fuse_dirent { + __u64 ino; + __u64 off; + __u32 namelen; + __u32 type; + char name[0]; +}; + +#define FUSE_NAME_OFFSET ((unsigned) ((struct fuse_dirent *) 0)->name) +#define FUSE_DIRENT_ALIGN(x) (((x) + sizeof(__u64) - 1) & ~(sizeof(__u64) - 1)) +#define FUSE_DIRENT_SIZE(d) \ + FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen) -- cgit v1.2.3 From 9e6268db496a2592e89457537ea54a496feabb77 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:29 -0700 Subject: [PATCH] FUSE - read-write operations This patch adds the write filesystem operations of FUSE. The following operations are added: o setattr o symlink o mknod o mkdir o create o unlink o rmdir o rename o link Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 43 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 41 insertions(+), 2 deletions(-) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index 21b9ba16f8d5..19d69a3e1623 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -11,7 +11,7 @@ #include /** Version number of this interface */ -#define FUSE_KERNEL_VERSION 6 +#define FUSE_KERNEL_VERSION 7 /** Minor version number of this interface */ #define FUSE_KERNEL_MINOR_VERSION 1 @@ -52,12 +52,28 @@ struct fuse_kstatfs { __u32 namelen; }; +#define FATTR_MODE (1 << 0) +#define FATTR_UID (1 << 1) +#define FATTR_GID (1 << 2) +#define FATTR_SIZE (1 << 3) +#define FATTR_ATIME (1 << 4) +#define FATTR_MTIME (1 << 5) +#define FATTR_CTIME (1 << 6) + enum fuse_opcode { FUSE_LOOKUP = 1, FUSE_FORGET = 2, /* no reply */ FUSE_GETATTR = 3, + FUSE_SETATTR = 4, FUSE_READLINK = 5, + FUSE_SYMLINK = 6, FUSE_GETDIR = 7, + FUSE_MKNOD = 8, + FUSE_MKDIR = 9, + FUSE_UNLINK = 10, + FUSE_RMDIR = 11, + FUSE_RENAME = 12, + FUSE_LINK = 13, FUSE_STATFS = 17, FUSE_INIT = 26 }; @@ -66,6 +82,7 @@ enum fuse_opcode { #define FUSE_MAX_IN 8192 #define FUSE_NAME_MAX 1024 +#define FUSE_SYMLINK_MAX 4096 struct fuse_entry_out { __u64 nodeid; /* Inode ID */ @@ -79,7 +96,7 @@ struct fuse_entry_out { }; struct fuse_forget_in { - __u64 version; + __u64 nlookup; }; struct fuse_attr_out { @@ -93,6 +110,28 @@ struct fuse_getdir_out { __u32 fd; }; +struct fuse_mknod_in { + __u32 mode; + __u32 rdev; +}; + +struct fuse_mkdir_in { + __u32 mode; +}; + +struct fuse_rename_in { + __u64 newdir; +}; + +struct fuse_link_in { + __u64 oldnodeid; +}; + +struct fuse_setattr_in { + __u32 valid; + struct fuse_attr attr; +}; + struct fuse_statfs_out { struct fuse_kstatfs st; }; -- cgit v1.2.3 From b6aeadeda22a9aa322fdfcd3f4c69ccf0da5cbdd Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:30 -0700 Subject: [PATCH] FUSE - file operations This patch adds the file operations of FUSE. The following operations are added: o open o flush o release o fsync o readpage o commit_write Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index 19d69a3e1623..61f34636ffbc 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -74,7 +74,13 @@ enum fuse_opcode { FUSE_RMDIR = 11, FUSE_RENAME = 12, FUSE_LINK = 13, + FUSE_OPEN = 14, + FUSE_READ = 15, + FUSE_WRITE = 16, FUSE_STATFS = 17, + FUSE_RELEASE = 18, + FUSE_FSYNC = 20, + FUSE_FLUSH = 25, FUSE_INIT = 26 }; @@ -132,10 +138,51 @@ struct fuse_setattr_in { struct fuse_attr attr; }; +struct fuse_open_in { + __u32 flags; +}; + +struct fuse_open_out { + __u64 fh; + __u32 open_flags; +}; + +struct fuse_release_in { + __u64 fh; + __u32 flags; +}; + +struct fuse_flush_in { + __u64 fh; + __u32 flush_flags; +}; + +struct fuse_read_in { + __u64 fh; + __u64 offset; + __u32 size; +}; + +struct fuse_write_in { + __u64 fh; + __u64 offset; + __u32 size; + __u32 write_flags; +}; + +struct fuse_write_out { + __u32 size; +}; + struct fuse_statfs_out { struct fuse_kstatfs st; }; +struct fuse_fsync_in { + __u64 fh; + __u32 fsync_flags; +}; + struct fuse_init_in_out { __u32 major; __u32 minor; -- cgit v1.2.3 From 92a8780e1136c5ca0c7ed940000d399943d1576e Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:31 -0700 Subject: [PATCH] FUSE - extended attribute operations This patch adds the extended attribute operations to FUSE. The following operations are added: o getxattr o setxattr o listxattr o removexattr Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index 61f34636ffbc..bf564edf9905 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -80,6 +80,10 @@ enum fuse_opcode { FUSE_STATFS = 17, FUSE_RELEASE = 18, FUSE_FSYNC = 20, + FUSE_SETXATTR = 21, + FUSE_GETXATTR = 22, + FUSE_LISTXATTR = 23, + FUSE_REMOVEXATTR = 24, FUSE_FLUSH = 25, FUSE_INIT = 26 }; @@ -89,6 +93,7 @@ enum fuse_opcode { #define FUSE_NAME_MAX 1024 #define FUSE_SYMLINK_MAX 4096 +#define FUSE_XATTR_SIZE_MAX 4096 struct fuse_entry_out { __u64 nodeid; /* Inode ID */ @@ -183,6 +188,19 @@ struct fuse_fsync_in { __u32 fsync_flags; }; +struct fuse_setxattr_in { + __u32 size; + __u32 flags; +}; + +struct fuse_getxattr_in { + __u32 size; +}; + +struct fuse_getxattr_out { + __u32 size; +}; + struct fuse_init_in_out { __u32 major; __u32 minor; -- cgit v1.2.3 From 06663267b4b1e85ece73236ea720355668d4f736 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:32 -0700 Subject: [PATCH] FUSE: add padding Add padding to structures to make sizes the same on 32bit and 64bit archs. Initial testing and test machine generously provided by Franco Broi. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index bf564edf9905..e9b814e16c58 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -25,6 +25,9 @@ /** The minor number of the fuse character device */ #define FUSE_MINOR 229 +/* Make sure all structures are padded to 64bit boundary, so 32bit + userspace works under 64bit kernels */ + struct fuse_attr { __u64 ino; __u64 size; @@ -128,6 +131,7 @@ struct fuse_mknod_in { struct fuse_mkdir_in { __u32 mode; + __u32 padding; }; struct fuse_rename_in { @@ -140,32 +144,38 @@ struct fuse_link_in { struct fuse_setattr_in { __u32 valid; + __u32 padding; struct fuse_attr attr; }; struct fuse_open_in { __u32 flags; + __u32 padding; }; struct fuse_open_out { __u64 fh; __u32 open_flags; + __u32 padding; }; struct fuse_release_in { __u64 fh; __u32 flags; + __u32 padding; }; struct fuse_flush_in { __u64 fh; __u32 flush_flags; + __u32 padding; }; struct fuse_read_in { __u64 fh; __u64 offset; __u32 size; + __u32 padding; }; struct fuse_write_in { @@ -177,6 +187,7 @@ struct fuse_write_in { struct fuse_write_out { __u32 size; + __u32 padding; }; struct fuse_statfs_out { @@ -186,6 +197,7 @@ struct fuse_statfs_out { struct fuse_fsync_in { __u64 fh; __u32 fsync_flags; + __u32 padding; }; struct fuse_setxattr_in { @@ -195,10 +207,12 @@ struct fuse_setxattr_in { struct fuse_getxattr_in { __u32 size; + __u32 padding; }; struct fuse_getxattr_out { __u32 size; + __u32 padding; }; struct fuse_init_in_out { @@ -214,6 +228,7 @@ struct fuse_in_header { __u32 uid; __u32 gid; __u32 pid; + __u32 padding; }; struct fuse_out_header { -- cgit v1.2.3 From 04730fef1f9c7277e5c730b193e681ac095b0507 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:36 -0700 Subject: [PATCH] fuse: transfer readdir data through device This patch removes a long lasting "hack" in FUSE, which used a separate channel (a file descriptor refering to a disk-file) to transfer directory contents from userspace to the kernel. The patch adds three new operations (OPENDIR, READDIR, RELEASEDIR), which have semantics and implementation exactly maching the respective file operations (OPEN, READ, RELEASE). This simplifies the directory reading code. Also disk space is not necessary, which can be important in embedded systems. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index e9b814e16c58..cdfaa51b9018 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -70,7 +70,6 @@ enum fuse_opcode { FUSE_SETATTR = 4, FUSE_READLINK = 5, FUSE_SYMLINK = 6, - FUSE_GETDIR = 7, FUSE_MKNOD = 8, FUSE_MKDIR = 9, FUSE_UNLINK = 10, @@ -88,7 +87,10 @@ enum fuse_opcode { FUSE_LISTXATTR = 23, FUSE_REMOVEXATTR = 24, FUSE_FLUSH = 25, - FUSE_INIT = 26 + FUSE_INIT = 26, + FUSE_OPENDIR = 27, + FUSE_READDIR = 28, + FUSE_RELEASEDIR = 29 }; /* Conservative buffer size for the client */ @@ -120,10 +122,6 @@ struct fuse_attr_out { struct fuse_attr attr; }; -struct fuse_getdir_out { - __u32 fd; -}; - struct fuse_mknod_in { __u32 mode; __u32 rdev; -- cgit v1.2.3 From 45323fb76465a9576220c7427dbac7b1e7ad3caf Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:37 -0700 Subject: [PATCH] fuse: more flexible caching Make data caching behavior selectable on a per-open basis instead of per-mount. Compatibility for the old mount options 'kernel_cache' and 'direct_io' is retained in the userspace library (version 2.4.0-pre1 or later). Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index cdfaa51b9018..c65124a213a1 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -14,7 +14,7 @@ #define FUSE_KERNEL_VERSION 7 /** Minor version number of this interface */ -#define FUSE_KERNEL_MINOR_VERSION 1 +#define FUSE_KERNEL_MINOR_VERSION 2 /** The node ID of the root inode */ #define FUSE_ROOT_ID 1 @@ -63,6 +63,15 @@ struct fuse_kstatfs { #define FATTR_MTIME (1 << 5) #define FATTR_CTIME (1 << 6) +/** + * Flags returned by the OPEN request + * + * FOPEN_DIRECT_IO: bypass page cache for this open file + * FOPEN_KEEP_CACHE: don't invalidate the data cache on open + */ +#define FOPEN_DIRECT_IO (1 << 0) +#define FOPEN_KEEP_CACHE (1 << 1) + enum fuse_opcode { FUSE_LOOKUP = 1, FUSE_FORGET = 2, /* no reply */ -- cgit v1.2.3 From 8254798199332966e2ab647380c990193af7e854 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 9 Sep 2005 13:10:38 -0700 Subject: [PATCH] FUSE: add fsync operation for directories This patch adds a new FSYNCDIR request, which is sent when fsync is called on directories. This operation is available in libfuse 2.3-pre1 or greater. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index c65124a213a1..acbeb96a3353 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -99,7 +99,8 @@ enum fuse_opcode { FUSE_INIT = 26, FUSE_OPENDIR = 27, FUSE_READDIR = 28, - FUSE_RELEASEDIR = 29 + FUSE_RELEASEDIR = 29, + FUSE_FSYNCDIR = 30 }; /* Conservative buffer size for the client */ -- cgit v1.2.3 From 6ea05db06f32adac65b4c4e95ef998839149de12 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 30 Oct 2005 15:02:52 -0800 Subject: [PATCH] fuse: remove unused define Setting ctime is implicit in all setattr cases, so the FATTR_CTIME definition is unnecessary. It is used by neither the kernel nor by userspace. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fuse.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/fuse.h') diff --git a/include/linux/fuse.h b/include/linux/fuse.h index acbeb96a3353..f98854c2abd7 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -61,7 +61,6 @@ struct fuse_kstatfs { #define FATTR_SIZE (1 << 3) #define FATTR_ATIME (1 << 4) #define FATTR_MTIME (1 << 5) -#define FATTR_CTIME (1 << 6) /** * Flags returned by the OPEN request -- cgit v1.2.3