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qemu-e2k/hw/9pfs/9p.h
Greg Kurz 56f101ecce 9pfs: handle walk of ".." in the root directory 
The 9P spec at http://man.cat-v.org/plan_9/5/intro says:

All directories must support walks to the directory .. (dot-dot) meaning
parent directory, although by convention directories contain no explicit
entry for .. or . (dot).  The parent of the root directory of a server's
tree is itself.

This means that a client cannot walk further than the root directory
exported by the server. In other words, if the client wants to walk
"/.." or "/foo/../..", the server should answer like the request was
to walk "/".

This patch just does that:
- we cache the QID of the root directory at attach time
- during the walk we compare the QID of each path component with the root
  QID to detect if we're in a "/.." situation
- if so, we skip the current component and go to the next one

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-08-30 19:23:00 +01:00

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#ifndef QEMU_9P_H
#define QEMU_9P_H
#include <dirent.h>
#include <utime.h>
#include <sys/resource.h>
#include "fsdev/file-op-9p.h"
#include "fsdev/9p-iov-marshal.h"
#include "qemu/thread.h"
#include "qemu/coroutine.h"
enum {
P9_TLERROR = 6,
P9_RLERROR,
P9_TSTATFS = 8,
P9_RSTATFS,
P9_TLOPEN = 12,
P9_RLOPEN,
P9_TLCREATE = 14,
P9_RLCREATE,
P9_TSYMLINK = 16,
P9_RSYMLINK,
P9_TMKNOD = 18,
P9_RMKNOD,
P9_TRENAME = 20,
P9_RRENAME,
P9_TREADLINK = 22,
P9_RREADLINK,
P9_TGETATTR = 24,
P9_RGETATTR,
P9_TSETATTR = 26,
P9_RSETATTR,
P9_TXATTRWALK = 30,
P9_RXATTRWALK,
P9_TXATTRCREATE = 32,
P9_RXATTRCREATE,
P9_TREADDIR = 40,
P9_RREADDIR,
P9_TFSYNC = 50,
P9_RFSYNC,
P9_TLOCK = 52,
P9_RLOCK,
P9_TGETLOCK = 54,
P9_RGETLOCK,
P9_TLINK = 70,
P9_RLINK,
P9_TMKDIR = 72,
P9_RMKDIR,
P9_TRENAMEAT = 74,
P9_RRENAMEAT,
P9_TUNLINKAT = 76,
P9_RUNLINKAT,
P9_TVERSION = 100,
P9_RVERSION,
P9_TAUTH = 102,
P9_RAUTH,
P9_TATTACH = 104,
P9_RATTACH,
P9_TERROR = 106,
P9_RERROR,
P9_TFLUSH = 108,
P9_RFLUSH,
P9_TWALK = 110,
P9_RWALK,
P9_TOPEN = 112,
P9_ROPEN,
P9_TCREATE = 114,
P9_RCREATE,
P9_TREAD = 116,
P9_RREAD,
P9_TWRITE = 118,
P9_RWRITE,
P9_TCLUNK = 120,
P9_RCLUNK,
P9_TREMOVE = 122,
P9_RREMOVE,
P9_TSTAT = 124,
P9_RSTAT,
P9_TWSTAT = 126,
P9_RWSTAT,
};
/* qid.types */
enum {
P9_QTDIR = 0x80,
P9_QTAPPEND = 0x40,
P9_QTEXCL = 0x20,
P9_QTMOUNT = 0x10,
P9_QTAUTH = 0x08,
P9_QTTMP = 0x04,
P9_QTSYMLINK = 0x02,
P9_QTLINK = 0x01,
P9_QTFILE = 0x00,
};
enum p9_proto_version {
V9FS_PROTO_2000U = 0x01,
V9FS_PROTO_2000L = 0x02,
};
#define P9_NOTAG (u16)(~0)
#define P9_NOFID (u32)(~0)
#define P9_MAXWELEM 16
#define FID_REFERENCED 0x1
#define FID_NON_RECLAIMABLE 0x2
static inline char *rpath(FsContext *ctx, const char *path)
{
return g_strdup_printf("%s/%s", ctx->fs_root, path);
}
/*
* ample room for Twrite/Rread header
* size[4] Tread/Twrite tag[2] fid[4] offset[8] count[4]
*/
#define P9_IOHDRSZ 24
typedef struct V9fsPDU V9fsPDU;
struct V9fsState;
struct V9fsPDU
{
uint32_t size;
uint16_t tag;
uint8_t id;
uint8_t cancelled;
CoQueue complete;
struct V9fsState *s;
QLIST_ENTRY(V9fsPDU) next;
uint32_t idx;
};
/* FIXME
* 1) change user needs to set groups and stuff
*/
#define MAX_REQ 128
#define MAX_TAG_LEN 32
#define BUG_ON(cond) assert(!(cond))
typedef struct V9fsFidState V9fsFidState;
enum {
P9_FID_NONE = 0,
P9_FID_FILE,
P9_FID_DIR,
P9_FID_XATTR,
};
typedef struct V9fsConf
{
/* tag name for the device */
char *tag;
char *fsdev_id;
} V9fsConf;
typedef struct V9fsXattr
{
int64_t copied_len;
int64_t len;
void *value;
V9fsString name;
int flags;
} V9fsXattr;
typedef struct V9fsDir {
DIR *stream;
QemuMutex readdir_mutex;
} V9fsDir;
static inline void v9fs_readdir_lock(V9fsDir *dir)
{
qemu_mutex_lock(&dir->readdir_mutex);
}
static inline void v9fs_readdir_unlock(V9fsDir *dir)
{
qemu_mutex_unlock(&dir->readdir_mutex);
}
static inline void v9fs_readdir_init(V9fsDir *dir)
{
qemu_mutex_init(&dir->readdir_mutex);
}
/*
* Filled by fs driver on open and other
* calls.
*/
union V9fsFidOpenState {
int fd;
V9fsDir dir;
V9fsXattr xattr;
/*
* private pointer for fs drivers, that
* have its own internal representation of
* open files.
*/
void *private;
};
struct V9fsFidState
{
int fid_type;
int32_t fid;
V9fsPath path;
V9fsFidOpenState fs;
V9fsFidOpenState fs_reclaim;
int flags;
int open_flags;
uid_t uid;
int ref;
int clunked;
V9fsFidState *next;
V9fsFidState *rclm_lst;
};
typedef struct V9fsState
{
QLIST_HEAD(, V9fsPDU) free_list;
QLIST_HEAD(, V9fsPDU) active_list;
V9fsFidState *fid_list;
FileOperations *ops;
FsContext ctx;
char *tag;
enum p9_proto_version proto_version;
int32_t msize;
/*
* lock ensuring atomic path update
* on rename.
*/
CoRwlock rename_lock;
int32_t root_fid;
Error *migration_blocker;
V9fsConf fsconf;
V9fsQID root_qid;
} V9fsState;
/* 9p2000.L open flags */
#define P9_DOTL_RDONLY 00000000
#define P9_DOTL_WRONLY 00000001
#define P9_DOTL_RDWR 00000002
#define P9_DOTL_NOACCESS 00000003
#define P9_DOTL_CREATE 00000100
#define P9_DOTL_EXCL 00000200
#define P9_DOTL_NOCTTY 00000400
#define P9_DOTL_TRUNC 00001000
#define P9_DOTL_APPEND 00002000
#define P9_DOTL_NONBLOCK 00004000
#define P9_DOTL_DSYNC 00010000
#define P9_DOTL_FASYNC 00020000
#define P9_DOTL_DIRECT 00040000
#define P9_DOTL_LARGEFILE 00100000
#define P9_DOTL_DIRECTORY 00200000
#define P9_DOTL_NOFOLLOW 00400000
#define P9_DOTL_NOATIME 01000000
#define P9_DOTL_CLOEXEC 02000000
#define P9_DOTL_SYNC 04000000
/* 9p2000.L at flags */
#define P9_DOTL_AT_REMOVEDIR 0x200
/* 9P2000.L lock type */
#define P9_LOCK_TYPE_RDLCK 0
#define P9_LOCK_TYPE_WRLCK 1
#define P9_LOCK_TYPE_UNLCK 2
#define P9_LOCK_SUCCESS 0
#define P9_LOCK_BLOCKED 1
#define P9_LOCK_ERROR 2
#define P9_LOCK_GRACE 3
#define P9_LOCK_FLAGS_BLOCK 1
#define P9_LOCK_FLAGS_RECLAIM 2
typedef struct V9fsFlock
{
uint8_t type;
uint32_t flags;
uint64_t start; /* absolute offset */
uint64_t length;
uint32_t proc_id;
V9fsString client_id;
} V9fsFlock;
typedef struct V9fsGetlock
{
uint8_t type;
uint64_t start; /* absolute offset */
uint64_t length;
uint32_t proc_id;
V9fsString client_id;
} V9fsGetlock;
extern int open_fd_hw;
extern int total_open_fd;
static inline void v9fs_path_write_lock(V9fsState *s)
{
if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
qemu_co_rwlock_wrlock(&s->rename_lock);
}
}
static inline void v9fs_path_read_lock(V9fsState *s)
{
if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
qemu_co_rwlock_rdlock(&s->rename_lock);
}
}
static inline void v9fs_path_unlock(V9fsState *s)
{
if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
qemu_co_rwlock_unlock(&s->rename_lock);
}
}
static inline uint8_t v9fs_request_cancelled(V9fsPDU *pdu)
{
return pdu->cancelled;
}
extern void v9fs_reclaim_fd(V9fsPDU *pdu);
extern void v9fs_path_init(V9fsPath *path);
extern void v9fs_path_free(V9fsPath *path);
extern void v9fs_path_copy(V9fsPath *lhs, V9fsPath *rhs);
extern int v9fs_name_to_path(V9fsState *s, V9fsPath *dirpath,
const char *name, V9fsPath *path);
extern int v9fs_device_realize_common(V9fsState *s, Error **errp);
extern void v9fs_device_unrealize_common(V9fsState *s, Error **errp);
ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...);
ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...);
V9fsPDU *pdu_alloc(V9fsState *s);
void pdu_free(V9fsPDU *pdu);
void pdu_submit(V9fsPDU *pdu);
#endif
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