sdcard: a program to create a "virtual" /sdcard pointed at a path
sdcard is a program that uses FUSE to emulate FAT-on-sdcard style
directory permissions (all files are given fixed owner, group, and
permissions at creation, owner, group, and permissions are not
changeable, symlinks and hardlinks are not createable, etc.
usage: sdcard <path> <uid> <gid>
It must be run as root, but will change to uid/gid as soon as it
mounts a filesystem on /sdcard. It will refuse to run if uid or
gid are zero.
Change-Id: I9a5d2e5daaebeee632f8470172cbb77b7fa689f8
Signed-off-by: Brian Swetland <swetland@google.com>
diff --git a/sdcard/fuse.h b/sdcard/fuse.h
new file mode 100644
index 0000000..3138da9
--- /dev/null
+++ b/sdcard/fuse.h
@@ -0,0 +1,578 @@
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+/*
+ * from the libfuse FAQ (and consistent with the Linux Kernel license):
+ *
+ * Under what conditions may I distribute a filesystem that uses the
+ * raw kernel interface of FUSE?
+ *
+ * There are no restrictions whatsoever for using the raw kernel interface.
+ *
+ */
+
+/*
+ * This file defines the kernel interface of FUSE
+ *
+ * Protocol changelog:
+ *
+ * 7.9:
+ * - new fuse_getattr_in input argument of GETATTR
+ * - add lk_flags in fuse_lk_in
+ * - add lock_owner field to fuse_setattr_in, fuse_read_in and fuse_write_in
+ * - add blksize field to fuse_attr
+ * - add file flags field to fuse_read_in and fuse_write_in
+ *
+ * 7.10
+ * - add nonseekable open flag
+ *
+ * 7.11
+ * - add IOCTL message
+ * - add unsolicited notification support
+ * - add POLL message and NOTIFY_POLL notification
+ *
+ * 7.12
+ * - add umask flag to input argument of open, mknod and mkdir
+ * - add notification messages for invalidation of inodes and
+ * directory entries
+ *
+ * 7.13
+ * - make max number of background requests and congestion threshold
+ * tunables
+ */
+
+#ifndef _LINUX_FUSE_H
+#define _LINUX_FUSE_H
+
+#include <linux/types.h>
+
+/*
+ * Version negotiation:
+ *
+ * Both the kernel and userspace send the version they support in the
+ * INIT request and reply respectively.
+ *
+ * If the major versions match then both shall use the smallest
+ * of the two minor versions for communication.
+ *
+ * If the kernel supports a larger major version, then userspace shall
+ * reply with the major version it supports, ignore the rest of the
+ * INIT message and expect a new INIT message from the kernel with a
+ * matching major version.
+ *
+ * If the library supports a larger major version, then it shall fall
+ * back to the major protocol version sent by the kernel for
+ * communication and reply with that major version (and an arbitrary
+ * supported minor version).
+ */
+
+/** Version number of this interface */
+#define FUSE_KERNEL_VERSION 7
+
+/** Minor version number of this interface */
+#define FUSE_KERNEL_MINOR_VERSION 13
+
+/** The node ID of the root inode */
+#define FUSE_ROOT_ID 1
+
+/* Make sure all structures are padded to 64bit boundary, so 32bit
+ userspace works under 64bit kernels */
+
+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;
+ __u32 blksize;
+ __u32 padding;
+};
+
+struct fuse_kstatfs {
+ __u64 blocks;
+ __u64 bfree;
+ __u64 bavail;
+ __u64 files;
+ __u64 ffree;
+ __u32 bsize;
+ __u32 namelen;
+ __u32 frsize;
+ __u32 padding;
+ __u32 spare[6];
+};
+
+struct fuse_file_lock {
+ __u64 start;
+ __u64 end;
+ __u32 type;
+ __u32 pid; /* tgid */
+};
+
+/**
+ * Bitmasks for fuse_setattr_in.valid
+ */
+#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_FH (1 << 6)
+#define FATTR_ATIME_NOW (1 << 7)
+#define FATTR_MTIME_NOW (1 << 8)
+#define FATTR_LOCKOWNER (1 << 9)
+
+/**
+ * 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
+ * FOPEN_NONSEEKABLE: the file is not seekable
+ */
+#define FOPEN_DIRECT_IO (1 << 0)
+#define FOPEN_KEEP_CACHE (1 << 1)
+#define FOPEN_NONSEEKABLE (1 << 2)
+
+/**
+ * INIT request/reply flags
+ *
+ * FUSE_EXPORT_SUPPORT: filesystem handles lookups of "." and ".."
+ * FUSE_DONT_MASK: don't apply umask to file mode on create operations
+ */
+#define FUSE_ASYNC_READ (1 << 0)
+#define FUSE_POSIX_LOCKS (1 << 1)
+#define FUSE_FILE_OPS (1 << 2)
+#define FUSE_ATOMIC_O_TRUNC (1 << 3)
+#define FUSE_EXPORT_SUPPORT (1 << 4)
+#define FUSE_BIG_WRITES (1 << 5)
+#define FUSE_DONT_MASK (1 << 6)
+
+/**
+ * CUSE INIT request/reply flags
+ *
+ * CUSE_UNRESTRICTED_IOCTL: use unrestricted ioctl
+ */
+#define CUSE_UNRESTRICTED_IOCTL (1 << 0)
+
+/**
+ * Release flags
+ */
+#define FUSE_RELEASE_FLUSH (1 << 0)
+
+/**
+ * Getattr flags
+ */
+#define FUSE_GETATTR_FH (1 << 0)
+
+/**
+ * Lock flags
+ */
+#define FUSE_LK_FLOCK (1 << 0)
+
+/**
+ * WRITE flags
+ *
+ * FUSE_WRITE_CACHE: delayed write from page cache, file handle is guessed
+ * FUSE_WRITE_LOCKOWNER: lock_owner field is valid
+ */
+#define FUSE_WRITE_CACHE (1 << 0)
+#define FUSE_WRITE_LOCKOWNER (1 << 1)
+
+/**
+ * Read flags
+ */
+#define FUSE_READ_LOCKOWNER (1 << 1)
+
+/**
+ * Ioctl flags
+ *
+ * FUSE_IOCTL_COMPAT: 32bit compat ioctl on 64bit machine
+ * FUSE_IOCTL_UNRESTRICTED: not restricted to well-formed ioctls, retry allowed
+ * FUSE_IOCTL_RETRY: retry with new iovecs
+ *
+ * FUSE_IOCTL_MAX_IOV: maximum of in_iovecs + out_iovecs
+ */
+#define FUSE_IOCTL_COMPAT (1 << 0)
+#define FUSE_IOCTL_UNRESTRICTED (1 << 1)
+#define FUSE_IOCTL_RETRY (1 << 2)
+
+#define FUSE_IOCTL_MAX_IOV 256
+
+/**
+ * Poll flags
+ *
+ * FUSE_POLL_SCHEDULE_NOTIFY: request poll notify
+ */
+#define FUSE_POLL_SCHEDULE_NOTIFY (1 << 0)
+
+enum fuse_opcode {
+ FUSE_LOOKUP = 1,
+ FUSE_FORGET = 2, /* no reply */
+ FUSE_GETATTR = 3,
+ FUSE_SETATTR = 4,
+ FUSE_READLINK = 5,
+ FUSE_SYMLINK = 6,
+ FUSE_MKNOD = 8,
+ FUSE_MKDIR = 9,
+ FUSE_UNLINK = 10,
+ 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_SETXATTR = 21,
+ FUSE_GETXATTR = 22,
+ FUSE_LISTXATTR = 23,
+ FUSE_REMOVEXATTR = 24,
+ FUSE_FLUSH = 25,
+ FUSE_INIT = 26,
+ FUSE_OPENDIR = 27,
+ FUSE_READDIR = 28,
+ FUSE_RELEASEDIR = 29,
+ FUSE_FSYNCDIR = 30,
+ FUSE_GETLK = 31,
+ FUSE_SETLK = 32,
+ FUSE_SETLKW = 33,
+ FUSE_ACCESS = 34,
+ FUSE_CREATE = 35,
+ FUSE_INTERRUPT = 36,
+ FUSE_BMAP = 37,
+ FUSE_DESTROY = 38,
+ FUSE_IOCTL = 39,
+ FUSE_POLL = 40,
+
+ /* CUSE specific operations */
+ CUSE_INIT = 4096,
+};
+
+enum fuse_notify_code {
+ FUSE_NOTIFY_POLL = 1,
+ FUSE_NOTIFY_INVAL_INODE = 2,
+ FUSE_NOTIFY_INVAL_ENTRY = 3,
+ FUSE_NOTIFY_CODE_MAX,
+};
+
+/* The read buffer is required to be at least 8k, but may be much larger */
+#define FUSE_MIN_READ_BUFFER 8192
+
+#define FUSE_COMPAT_ENTRY_OUT_SIZE 120
+
+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 nlookup;
+};
+
+struct fuse_getattr_in {
+ __u32 getattr_flags;
+ __u32 dummy;
+ __u64 fh;
+};
+
+#define FUSE_COMPAT_ATTR_OUT_SIZE 96
+
+struct fuse_attr_out {
+ __u64 attr_valid; /* Cache timeout for the attributes */
+ __u32 attr_valid_nsec;
+ __u32 dummy;
+ struct fuse_attr attr;
+};
+
+#define FUSE_COMPAT_MKNOD_IN_SIZE 8
+
+struct fuse_mknod_in {
+ __u32 mode;
+ __u32 rdev;
+ __u32 umask;
+ __u32 padding;
+};
+
+struct fuse_mkdir_in {
+ __u32 mode;
+ __u32 umask;
+};
+
+struct fuse_rename_in {
+ __u64 newdir;
+};
+
+struct fuse_link_in {
+ __u64 oldnodeid;
+};
+
+struct fuse_setattr_in {
+ __u32 valid;
+ __u32 padding;
+ __u64 fh;
+ __u64 size;
+ __u64 lock_owner;
+ __u64 atime;
+ __u64 mtime;
+ __u64 unused2;
+ __u32 atimensec;
+ __u32 mtimensec;
+ __u32 unused3;
+ __u32 mode;
+ __u32 unused4;
+ __u32 uid;
+ __u32 gid;
+ __u32 unused5;
+};
+
+struct fuse_open_in {
+ __u32 flags;
+ __u32 unused;
+};
+
+struct fuse_create_in {
+ __u32 flags;
+ __u32 mode;
+ __u32 umask;
+ __u32 padding;
+};
+
+struct fuse_open_out {
+ __u64 fh;
+ __u32 open_flags;
+ __u32 padding;
+};
+
+struct fuse_release_in {
+ __u64 fh;
+ __u32 flags;
+ __u32 release_flags;
+ __u64 lock_owner;
+};
+
+struct fuse_flush_in {
+ __u64 fh;
+ __u32 unused;
+ __u32 padding;
+ __u64 lock_owner;
+};
+
+struct fuse_read_in {
+ __u64 fh;
+ __u64 offset;
+ __u32 size;
+ __u32 read_flags;
+ __u64 lock_owner;
+ __u32 flags;
+ __u32 padding;
+};
+
+#define FUSE_COMPAT_WRITE_IN_SIZE 24
+
+struct fuse_write_in {
+ __u64 fh;
+ __u64 offset;
+ __u32 size;
+ __u32 write_flags;
+ __u64 lock_owner;
+ __u32 flags;
+ __u32 padding;
+};
+
+struct fuse_write_out {
+ __u32 size;
+ __u32 padding;
+};
+
+#define FUSE_COMPAT_STATFS_SIZE 48
+
+struct fuse_statfs_out {
+ struct fuse_kstatfs st;
+};
+
+struct fuse_fsync_in {
+ __u64 fh;
+ __u32 fsync_flags;
+ __u32 padding;
+};
+
+struct fuse_setxattr_in {
+ __u32 size;
+ __u32 flags;
+};
+
+struct fuse_getxattr_in {
+ __u32 size;
+ __u32 padding;
+};
+
+struct fuse_getxattr_out {
+ __u32 size;
+ __u32 padding;
+};
+
+struct fuse_lk_in {
+ __u64 fh;
+ __u64 owner;
+ struct fuse_file_lock lk;
+ __u32 lk_flags;
+ __u32 padding;
+};
+
+struct fuse_lk_out {
+ struct fuse_file_lock lk;
+};
+
+struct fuse_access_in {
+ __u32 mask;
+ __u32 padding;
+};
+
+struct fuse_init_in {
+ __u32 major;
+ __u32 minor;
+ __u32 max_readahead;
+ __u32 flags;
+};
+
+struct fuse_init_out {
+ __u32 major;
+ __u32 minor;
+ __u32 max_readahead;
+ __u32 flags;
+ __u16 max_background;
+ __u16 congestion_threshold;
+ __u32 max_write;
+};
+
+#define CUSE_INIT_INFO_MAX 4096
+
+struct cuse_init_in {
+ __u32 major;
+ __u32 minor;
+ __u32 unused;
+ __u32 flags;
+};
+
+struct cuse_init_out {
+ __u32 major;
+ __u32 minor;
+ __u32 unused;
+ __u32 flags;
+ __u32 max_read;
+ __u32 max_write;
+ __u32 dev_major; /* chardev major */
+ __u32 dev_minor; /* chardev minor */
+ __u32 spare[10];
+};
+
+struct fuse_interrupt_in {
+ __u64 unique;
+};
+
+struct fuse_bmap_in {
+ __u64 block;
+ __u32 blocksize;
+ __u32 padding;
+};
+
+struct fuse_bmap_out {
+ __u64 block;
+};
+
+struct fuse_ioctl_in {
+ __u64 fh;
+ __u32 flags;
+ __u32 cmd;
+ __u64 arg;
+ __u32 in_size;
+ __u32 out_size;
+};
+
+struct fuse_ioctl_out {
+ __s32 result;
+ __u32 flags;
+ __u32 in_iovs;
+ __u32 out_iovs;
+};
+
+struct fuse_poll_in {
+ __u64 fh;
+ __u64 kh;
+ __u32 flags;
+ __u32 padding;
+};
+
+struct fuse_poll_out {
+ __u32 revents;
+ __u32 padding;
+};
+
+struct fuse_notify_poll_wakeup_out {
+ __u64 kh;
+};
+
+struct fuse_in_header {
+ __u32 len;
+ __u32 opcode;
+ __u64 unique;
+ __u64 nodeid;
+ __u32 uid;
+ __u32 gid;
+ __u32 pid;
+ __u32 padding;
+};
+
+struct fuse_out_header {
+ __u32 len;
+ __s32 error;
+ __u64 unique;
+};
+
+struct fuse_dirent {
+ __u64 ino;
+ __u64 off;
+ __u32 namelen;
+ __u32 type;
+ char name[0];
+};
+
+#define FUSE_NAME_OFFSET offsetof(struct fuse_dirent, 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)
+
+struct fuse_notify_inval_inode_out {
+ __u64 ino;
+ __s64 off;
+ __s64 len;
+};
+
+struct fuse_notify_inval_entry_out {
+ __u64 parent;
+ __u32 namelen;
+ __u32 padding;
+};
+
+#endif /* _LINUX_FUSE_H */