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9pfront.c
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9pfront.c
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/*
* Minimal 9pfs PV frontend for Mini-OS.
* Copyright (c) 2023 Juergen Gross, SUSE Software Solution GmbH
*/
#include <mini-os/os.h>
#include <mini-os/lib.h>
#include <mini-os/events.h>
#include <mini-os/fcntl.h>
#include <mini-os/gnttab.h>
#include <mini-os/semaphore.h>
#include <mini-os/wait.h>
#include <mini-os/xenbus.h>
#include <mini-os/xmalloc.h>
#include <errno.h>
#include <xen/io/9pfs.h>
#include <mini-os/9pfront.h>
#ifdef HAVE_LIBC
#define N_REQS 64
struct dev_9pfs {
int id;
char nodename[20];
unsigned int dom;
char *backend;
char *tag;
const char *mnt;
unsigned int msize_max;
struct xen_9pfs_data_intf *intf;
struct xen_9pfs_data data;
RING_IDX prod_pvt_out;
RING_IDX cons_pvt_in;
grant_ref_t ring_ref;
evtchn_port_t evtchn;
unsigned int ring_order;
xenbus_event_queue events;
unsigned int free_reqs;
struct req {
unsigned int id;
unsigned int next_free; /* N_REQS == end of list. */
unsigned int cmd;
int result;
bool inflight;
unsigned char *data; /* Returned data. */
} req[N_REQS];
struct wait_queue_head waitq;
struct semaphore ring_out_sem;
struct semaphore ring_in_sem;
unsigned long long fid_mask; /* Bit mask for free fids. */
};
struct file_9pfs {
uint32_t fid;
struct dev_9pfs *dev;
bool append;
};
#define DEFAULT_9PFS_RING_ORDER 4
/* P9 protocol commands (response is either cmd+1 or P9_CMD_ERROR). */
#define P9_CMD_VERSION 100
#define P9_CMD_ATTACH 104
#define P9_CMD_ERROR 107
#define P9_CMD_WALK 110
#define P9_CMD_OPEN 112
#define P9_CMD_CREATE 114
#define P9_CMD_READ 116
#define P9_CMD_WRITE 118
#define P9_CMD_CLUNK 120
#define P9_CMD_STAT 124
/* P9 protocol open flags. */
#define P9_OREAD 0 /* read */
#define P9_OWRITE 1 /* write */
#define P9_ORDWR 2 /* read and write */
#define P9_OTRUNC 16 /* or'ed in, truncate file first */
#define P9_QID_SIZE 13
struct p9_header {
uint32_t size;
uint8_t cmd;
uint16_t tag;
} __attribute__((packed));
struct p9_stat {
uint16_t size;
uint16_t type;
uint32_t dev;
uint8_t qid[P9_QID_SIZE];
uint32_t mode;
uint32_t atime;
uint32_t mtime;
uint64_t length;
char *name;
char *uid;
char *gid;
char *muid;
char *extension;
uint32_t n_uid;
uint32_t n_gid;
uint32_t n_muid;
};
#define P9_VERSION "9P2000.u"
#define P9_ROOT_FID 0
static unsigned int ftype_9pfs;
static void free_stat(struct p9_stat *stat)
{
free(stat->name);
free(stat->uid);
free(stat->gid);
free(stat->muid);
free(stat->extension);
}
static unsigned int get_fid(struct dev_9pfs *dev)
{
unsigned int fid;
fid = ffs(dev->fid_mask);
if ( fid )
dev->fid_mask &= ~(1ULL << (fid - 1));
return fid;
}
static void put_fid(struct dev_9pfs *dev, unsigned int fid)
{
if ( fid )
dev->fid_mask |= 1ULL << (fid - 1);
}
static struct req *get_free_req(struct dev_9pfs *dev)
{
struct req *req;
if ( dev->free_reqs == N_REQS )
return NULL;
req = dev->req + dev->free_reqs;
dev->free_reqs = req->next_free;
return req;
}
static void put_free_req(struct dev_9pfs *dev, struct req *req)
{
req->next_free = dev->free_reqs;
req->inflight = false;
req->data = NULL;
dev->free_reqs = req->id;
}
static unsigned int ring_out_free(struct dev_9pfs *dev)
{
RING_IDX ring_size = XEN_FLEX_RING_SIZE(dev->ring_order);
unsigned int queued;
queued = xen_9pfs_queued(dev->prod_pvt_out, dev->intf->out_cons, ring_size);
rmb();
return ring_size - queued;
}
static unsigned int ring_in_data(struct dev_9pfs *dev)
{
RING_IDX ring_size = XEN_FLEX_RING_SIZE(dev->ring_order);
unsigned int queued;
queued = xen_9pfs_queued(dev->intf->in_prod, dev->cons_pvt_in, ring_size);
rmb();
return queued;
}
static void copy_to_ring(struct dev_9pfs *dev, void *data, unsigned int len)
{
RING_IDX ring_size = XEN_FLEX_RING_SIZE(dev->ring_order);
RING_IDX prod = xen_9pfs_mask(dev->prod_pvt_out, ring_size);
RING_IDX cons = xen_9pfs_mask(dev->intf->out_cons, ring_size);
xen_9pfs_write_packet(dev->data.out, data, len, &prod, cons, ring_size);
dev->prod_pvt_out += len;
}
static void copy_from_ring(struct dev_9pfs *dev, void *data, unsigned int len)
{
RING_IDX ring_size = XEN_FLEX_RING_SIZE(dev->ring_order);
RING_IDX prod = xen_9pfs_mask(dev->intf->in_prod, ring_size);
RING_IDX cons = xen_9pfs_mask(dev->cons_pvt_in, ring_size);
xen_9pfs_read_packet(data, dev->data.in, len, prod, &cons, ring_size);
dev->cons_pvt_in += len;
}
/*
* send_9p() and rcv_9p() are using a special format string for specifying
* the kind of data sent/expected. Each data item is represented by a single
* character:
* b: 1 byte unsigned integer (uint8_t)
* Only valid for sending.
* u: 2 byte unsigned integer (uint16_t)
* U: 4 byte unsigned integer (uint32_t)
* L: 8 byte unsigned integer (uint64_t)
* S: String (2 byte length + <length> characters)
* in the rcv_9p() case the data for string is allocated (length omitted,
* string terminated by a NUL character)
* D: Binary data (4 byte length + <length> bytes of data), requires a length
* and a buffer pointer parameter.
* Q: A 13 byte "qid", consisting of 1 byte file type, 4 byte file version
* and 8 bytes unique file id. Only valid for receiving.
*/
static void send_9p(struct dev_9pfs *dev, struct req *req, const char *fmt, ...)
{
struct p9_header hdr;
va_list ap, aq;
const char *f;
uint64_t longval;
uint32_t intval;
uint16_t shortval;
uint16_t len;
uint8_t byte;
uint8_t *data;
char *strval;
hdr.size = sizeof(hdr);
hdr.cmd = req->cmd;
hdr.tag = req->id;
va_start(ap, fmt);
va_copy(aq, ap);
for ( f = fmt; *f; f++ )
{
switch ( *f )
{
case 'b':
hdr.size += 1;
byte = va_arg(aq, unsigned int);
break;
case 'u':
hdr.size += 2;
shortval = va_arg(aq, unsigned int);
break;
case 'U':
hdr.size += 4;
intval = va_arg(aq, unsigned int);
break;
case 'L':
hdr.size += 8;
longval = va_arg(aq, uint64_t);
break;
case 'S':
hdr.size += 2;
strval = va_arg(aq, char *);
hdr.size += strlen(strval);
break;
case 'D':
hdr.size += 4;
intval = va_arg(aq, unsigned int);
hdr.size += intval;
data = va_arg(aq, uint8_t *);
break;
default:
printk("send_9p: unknown format character %c\n", *f);
break;
}
}
va_end(aq);
/*
* Waiting for free space must be done in the critical section!
* Otherwise we might get overtaken by other short requests.
*/
down(&dev->ring_out_sem);
wait_event(dev->waitq, ring_out_free(dev) >= hdr.size);
copy_to_ring(dev, &hdr, sizeof(hdr));
for ( f = fmt; *f; f++ )
{
switch ( *f )
{
case 'b':
byte = va_arg(ap, unsigned int);
copy_to_ring(dev, &byte, sizeof(byte));
break;
case 'u':
shortval = va_arg(ap, unsigned int);
copy_to_ring(dev, &shortval, sizeof(shortval));
break;
case 'U':
intval = va_arg(ap, unsigned int);
copy_to_ring(dev, &intval, sizeof(intval));
break;
case 'L':
longval = va_arg(ap, uint64_t);
copy_to_ring(dev, &longval, sizeof(longval));
break;
case 'S':
strval = va_arg(ap, char *);
len = strlen(strval);
copy_to_ring(dev, &len, sizeof(len));
copy_to_ring(dev, strval, len);
break;
case 'D':
intval = va_arg(ap, unsigned int);
copy_to_ring(dev, &intval, sizeof(intval));
data = va_arg(ap, uint8_t *);
copy_to_ring(dev, data, intval);
break;
}
}
wmb(); /* Data on ring must be seen before updating index. */
dev->intf->out_prod = dev->prod_pvt_out;
req->inflight = true;
up(&dev->ring_out_sem);
va_end(ap);
notify_remote_via_evtchn(dev->evtchn);
}
/*
* Using an opportunistic approach for receiving data: in case multiple
* requests are outstanding (which is very unlikely), we nevertheless need
* to consume all data available until we reach the desired request.
* For requests other than the one we are waiting for, we link the complete
* data to the request via an intermediate buffer. For our own request we can
* omit that buffer and directly fill the caller provided variables.
*
* Helper functions:
*
* copy_bufs(): copy raw data into a target buffer. There can be 2 source
* buffers involved (in case the copy is done from the ring and it is across
* the ring end). The buffer pointers and lengths are updated according to
* the number of bytes copied.
*
* rcv_9p_copy(): copy the data (without the generic header) of a 9p response
* to the specified variables using the specified format string for
* deciphering the single item types. The decision whether to copy from the
* ring or an allocated buffer is done via the "hdr" parameter, which is
* NULL in the buffer case (in that case the header is located at the start
* of the buffer).
*
* rcv_9p_one(): Checks for an already filled buffer with the correct tag in
* it. If none is found, consumes one response. It checks the tag of the
* response in order to decide whether to allocate a buffer for putting the
* data into, or to fill the user supplied variables. Return true, if the
* tag did match. Waits if no data is ready to be consumed.
*/
static void copy_bufs(unsigned char **buf1, unsigned char **buf2,
unsigned int *len1, unsigned int *len2,
void *target, unsigned int len)
{
if ( len <= *len1 )
{
memcpy(target, *buf1, len);
*buf1 += len;
*len1 -= len;
}
else
{
memcpy(target, *buf1, *len1);
target = (char *)target + *len1;
len -= *len1;
*buf1 = *buf2;
*len1 = *len2;
*buf2 = NULL;
*len2 = 0;
if ( len > *len1 )
{
printk("9pfs: short copy (dropping %u bytes)\n", len - *len1);
len = *len1;
}
memcpy(target, *buf1, len);
*buf1 += len;
*len1 -= len;
}
}
static void rcv_9p_copy(struct dev_9pfs *dev, struct req *req,
struct p9_header *hdr, const char *fmt, va_list ap)
{
struct p9_header *h = hdr ? hdr : (void *)req->data;
RING_IDX cons = dev->cons_pvt_in + h->size - sizeof(*h);
RING_IDX ring_size = XEN_FLEX_RING_SIZE(dev->ring_order);
unsigned char *buf1, *buf2;
unsigned int len1, len2;
const char *f;
char *str;
uint16_t len;
uint32_t err;
uint16_t *shortval;
uint32_t *val;
uint64_t *longval;
uint8_t *data;
char **strval;
uint8_t *qval;
if ( hdr )
{
buf1 = xen_9pfs_get_ring_ptr(dev->data.in, dev->cons_pvt_in, ring_size);
buf2 = xen_9pfs_get_ring_ptr(dev->data.in, 0, ring_size);
len1 = ring_size - xen_9pfs_mask(dev->cons_pvt_in, ring_size);
if ( len1 > h->size - sizeof(*h) )
len1 = h->size - sizeof(*h);
len2 = h->size - sizeof(*h) - len1;
}
else
{
buf1 = req->data + sizeof(*h);
buf2 = NULL;
len1 = h->size - sizeof(*h);
len2 = 0;
}
if ( h->cmd == P9_CMD_ERROR )
{
copy_bufs(&buf1, &buf2, &len1, &len2, &len, sizeof(len));
str = malloc(len + 1);
copy_bufs(&buf1, &buf2, &len1, &len2, str, len);
str[len] = 0;
printk("9pfs: request %u resulted in \"%s\"\n", req->cmd, str);
free(str);
err = EIO;
copy_bufs(&buf1, &buf2, &len1, &len2, &err, sizeof(err));
req->result = err;
if ( hdr )
dev->cons_pvt_in = cons;
return;
}
if ( h->cmd != req->cmd + 1 )
{
req->result = EDOM;
printk("9pfs: illegal response: wrong return type (%u instead of %u)\n",
h->cmd, req->cmd + 1);
if ( hdr )
dev->cons_pvt_in = cons;
return;
}
req->result = 0;
for ( f = fmt; *f; f++ )
{
switch ( *f )
{
case 'u':
shortval = va_arg(ap, uint16_t *);
copy_bufs(&buf1, &buf2, &len1, &len2, shortval, sizeof(*shortval));
break;
case 'U':
val = va_arg(ap, uint32_t *);
copy_bufs(&buf1, &buf2, &len1, &len2, val, sizeof(*val));
break;
case 'L':
longval = va_arg(ap, uint64_t *);
copy_bufs(&buf1, &buf2, &len1, &len2, longval, sizeof(*longval));
break;
case 'S':
strval = va_arg(ap, char **);
copy_bufs(&buf1, &buf2, &len1, &len2, &len, sizeof(len));
*strval = malloc(len + 1);
copy_bufs(&buf1, &buf2, &len1, &len2, *strval, len);
(*strval)[len] = 0;
break;
case 'D':
val = va_arg(ap, uint32_t *);
data = va_arg(ap, uint8_t *);
copy_bufs(&buf1, &buf2, &len1, &len2, val, sizeof(*val));
copy_bufs(&buf1, &buf2, &len1, &len2, data, *val);
break;
case 'Q':
qval = va_arg(ap, uint8_t *);
copy_bufs(&buf1, &buf2, &len1, &len2, qval, P9_QID_SIZE);
break;
default:
printk("rcv_9p: unknown format character %c\n", *f);
break;
}
}
if ( hdr )
dev->cons_pvt_in = cons;
}
static bool rcv_9p_one(struct dev_9pfs *dev, struct req *req, const char *fmt,
va_list ap)
{
struct p9_header hdr;
struct req *tmp;
if ( req->data )
{
rcv_9p_copy(dev, req, NULL, fmt, ap);
free(req->data);
req->data = NULL;
return true;
}
wait_event(dev->waitq, ring_in_data(dev) >= sizeof(hdr));
copy_from_ring(dev, &hdr, sizeof(hdr));
wait_event(dev->waitq, ring_in_data(dev) >= hdr.size - sizeof(hdr));
tmp = dev->req + hdr.tag;
if ( hdr.tag >= N_REQS || !tmp->inflight )
{
printk("9pfs: illegal response: %s\n",
hdr.tag >= N_REQS ? "tag out of bounds" : "request not pending");
dev->cons_pvt_in += hdr.size - sizeof(hdr);
return false;
}
tmp->inflight = false;
if ( tmp != req )
{
tmp->data = malloc(hdr.size);
memcpy(tmp->data, &hdr, sizeof(hdr));
copy_from_ring(dev, tmp->data + sizeof(hdr), hdr.size - sizeof(hdr));
return false;
}
rcv_9p_copy(dev, req, &hdr, fmt, ap);
return true;
}
static void rcv_9p(struct dev_9pfs *dev, struct req *req, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
down(&dev->ring_in_sem);
while ( !rcv_9p_one(dev, req, fmt, ap) );
rmb(); /* Read all data before updating ring index. */
dev->intf->in_cons = dev->cons_pvt_in;
notify_remote_via_evtchn(dev->evtchn);
up(&dev->ring_in_sem);
va_end(ap);
}
static int p9_version(struct dev_9pfs *dev)
{
unsigned int msize = XEN_FLEX_RING_SIZE(dev->ring_order) / 2;
struct req *req = get_free_req(dev);
char *verret;
int ret;
if ( !req )
return EAGAIN;
req->cmd = P9_CMD_VERSION;
send_9p(dev, req, "US", msize, P9_VERSION);
rcv_9p(dev, req, "US", &dev->msize_max, &verret);
ret = req->result;
put_free_req(dev, req);
if ( ret )
return ret;
if ( strcmp(verret, P9_VERSION) )
ret = ENOMSG;
free(verret);
return ret;
}
static int p9_attach(struct dev_9pfs *dev)
{
uint32_t fid = P9_ROOT_FID;
uint32_t afid = 0;
uint32_t uid = 0;
uint8_t qid[P9_QID_SIZE];
struct req *req = get_free_req(dev);
int ret;
if ( !req )
return EAGAIN;
req->cmd = P9_CMD_ATTACH;
send_9p(dev, req, "UUSSU", fid, afid, "root", "root", uid);
rcv_9p(dev, req, "Q", qid);
ret = req->result;
put_free_req(dev, req);
return ret;
}
static int p9_clunk(struct dev_9pfs *dev, uint32_t fid)
{
struct req *req = get_free_req(dev);
int ret;
if ( !req )
return EAGAIN;
req->cmd = P9_CMD_CLUNK;
send_9p(dev, req, "U", fid);
rcv_9p(dev, req, "");
ret = req->result;
put_free_req(dev, req);
return ret;
}
static int p9_walk(struct dev_9pfs *dev, uint32_t fid, uint32_t newfid,
char *name)
{
struct req *req = get_free_req(dev);
int ret;
uint16_t nqid;
uint8_t qid[P9_QID_SIZE];
if ( !req )
return EAGAIN;
req->cmd = P9_CMD_WALK;
if ( name[0] )
{
send_9p(dev, req, "UUuS", fid, newfid, 1, name);
rcv_9p(dev, req, "uQ", &nqid, qid);
}
else
{
send_9p(dev, req, "UUu", fid, newfid, 0);
rcv_9p(dev, req, "u", &nqid);
}
ret = req->result;
put_free_req(dev, req);
return ret;
}
static int p9_open(struct dev_9pfs *dev, uint32_t fid, uint8_t omode)
{
struct req *req = get_free_req(dev);
int ret;
uint8_t qid[P9_QID_SIZE];
uint32_t iounit;
if ( !req )
return EAGAIN;
req->cmd = P9_CMD_OPEN;
send_9p(dev, req, "Ub", fid, omode);
rcv_9p(dev, req, "QU", qid, &iounit);
ret = req->result;
put_free_req(dev, req);
return ret;
}
static int p9_create(struct dev_9pfs *dev, uint32_t fid, char *path,
uint32_t mode, uint8_t omode)
{
struct req *req = get_free_req(dev);
int ret;
uint8_t qid[P9_QID_SIZE];
uint32_t iounit;
if ( !req )
return EAGAIN;
req->cmd = P9_CMD_CREATE;
send_9p(dev, req, "USUbS", fid, path, mode, omode, "");
rcv_9p(dev, req, "QU", qid, &iounit);
ret = req->result;
put_free_req(dev, req);
return ret;
}
static int p9_stat(struct dev_9pfs *dev, uint32_t fid, struct p9_stat *stat)
{
struct req *req = get_free_req(dev);
uint16_t total;
int ret;
if ( !req )
return EAGAIN;
memset(stat, 0, sizeof(*stat));
req->cmd = P9_CMD_STAT;
send_9p(dev, req, "U", fid);
rcv_9p(dev, req, "uuuUQUUULSSSSSUUU", &total, &stat->size, &stat->type,
&stat->dev, stat->qid, &stat->mode, &stat->atime, &stat->mtime,
&stat->length, &stat->name, &stat->uid, &stat->gid, &stat->muid,
&stat->extension, &stat->n_uid, &stat->n_gid, &stat->n_muid);
ret = req->result;
if ( ret )
free_stat(stat);
put_free_req(dev, req);
return ret;
}
static int p9_read(struct dev_9pfs *dev, uint32_t fid, uint64_t offset,
uint8_t *data, uint32_t len)
{
struct req *req = get_free_req(dev);
int ret = 0;
uint32_t count, count_max;
if ( !req )
{
errno = EAGAIN;
return -1;
}
req->cmd = P9_CMD_READ;
count_max = dev->msize_max - (sizeof(struct p9_header) + sizeof(uint32_t));
while ( len )
{
count = len;
if ( count > count_max )
count = count_max;
send_9p(dev, req, "ULU", fid, offset, count);
rcv_9p(dev, req, "D", &count, data);
if ( !count )
break;
if ( req->result )
{
ret = -1;
errno = EIO;
printk("9pfs: read got error %d\n", req->result);
break;
}
ret += count;
offset += count;
data += count;
len -= count;
}
put_free_req(dev, req);
return ret;
}
static int p9_write(struct dev_9pfs *dev, uint32_t fid, uint64_t offset,
const uint8_t *data, uint32_t len)
{
struct req *req = get_free_req(dev);
int ret = 0;
uint32_t count, count_max;
if ( !req )
{
errno = EAGAIN;
return -1;
}
req->cmd = P9_CMD_WRITE;
count_max = dev->msize_max - (sizeof(struct p9_header) + sizeof(uint32_t) +
sizeof(uint64_t) + sizeof(uint32_t));
while ( len )
{
count = len;
if ( count > count_max )
count = count_max;
send_9p(dev, req, "ULD", fid, offset, count, data);
rcv_9p(dev, req, "U", &count);
if ( req->result )
{
ret = -1;
errno = EIO;
printk("9pfs: write got error %d\n", req->result);
break;
}
ret += count;
offset += count;
data += count;
len -= count;
}
put_free_req(dev, req);
return ret;
}
/*
* Walk from root <steps> levels with the levels listed in <*paths> as a
* sequence of names. Returns the number of steps not having been able to
* walk, with <*paths> pointing at the name of the failing walk step.
* <fid> will be associated with the last successful walk step. Note that
* the first step should always succeed, as it is an empty walk in order
* to start at the root (needed for creating new files in root).
*/
static unsigned int walk_9pfs(struct dev_9pfs *dev, uint32_t fid,
unsigned int steps, char **paths)
{
uint32_t curr_fid = P9_ROOT_FID;
int ret;
while ( steps-- )
{
ret = p9_walk(dev, curr_fid, fid, *paths);
if ( ret )
return steps + 1;
curr_fid = fid;
*paths += strlen(*paths) + 1;
}
return 0;
}
static unsigned int split_path(const char *pathname, char **split_ptr)
{
unsigned int parts = 1;
char *p;
*split_ptr = strdup(pathname);
for ( p = strchr(*split_ptr, '/'); p; p = strchr(p + 1, '/') )
{
*p = 0;
parts++;
}
return parts;
}
static bool path_canonical(const char *pathname)
{
unsigned int len = strlen(pathname);
const char *c;
/* Empty path is allowed. */
if ( !len )
return true;
/* No trailing '/'. */
if ( pathname[len - 1] == '/' )
return false;
/* No self or parent references. */
c = pathname;
while ( (c = strstr(c, "/.")) != NULL )
{
if ( c[2] == '.' )
c++;
if ( c[2] == 0 || c[2] == '/' )
return false;
c += 2;
}
/* No "//". */
if ( strstr(pathname, "//") )
return false;
return true;
}
static int connect_9pfs(struct dev_9pfs *dev)
{
int ret;
ret = p9_version(dev);
if ( ret )
return ret;
return p9_attach(dev);
}
static void intr_9pfs(evtchn_port_t port, struct pt_regs *regs, void *data)
{
struct dev_9pfs *dev = data;
wake_up(&dev->waitq);
}
static int read_9pfs(struct file *file, void *buf, size_t nbytes)
{
struct file_9pfs *f9pfs = file->filedata;
int ret;
ret = p9_read(f9pfs->dev, f9pfs->fid, file->offset, buf, nbytes);
if ( ret >= 0 )
file->offset += ret;
return ret;
}
static int write_9pfs(struct file *file, const void *buf, size_t nbytes)
{
struct file_9pfs *f9pfs = file->filedata;
struct p9_stat stat;
int ret;
if ( f9pfs->append )
{
ret = p9_stat(f9pfs->dev, f9pfs->fid, &stat);
if ( ret )
{
errno = EIO;
return -1;
}
file->offset = stat.length;
free_stat(&stat);
}
ret = p9_write(f9pfs->dev, f9pfs->fid, file->offset, buf, nbytes);
if ( ret >= 0 )
file->offset += ret;
return ret;
}
static int close_9pfs(struct file *file)
{
struct file_9pfs *f9pfs = file->filedata;
if ( f9pfs->fid != P9_ROOT_FID )
{
p9_clunk(f9pfs->dev, f9pfs->fid);
put_fid(f9pfs->dev, f9pfs->fid);
}
free(f9pfs);
return 0;
}
static int open_9pfs(struct mount_point *mnt, const char *pathname, int flags,
mode_t mode)
{
int fd;
char *path = NULL;
char *p;
struct file *file;
struct file_9pfs *f9pfs;
uint16_t nwalk;
uint8_t omode;
int ret;
if ( !path_canonical(pathname) )
return EINVAL;
f9pfs = calloc(1, sizeof(*f9pfs));
f9pfs->dev = mnt->dev;
f9pfs->fid = P9_ROOT_FID;
fd = alloc_fd(ftype_9pfs);
file = get_file_from_fd(fd);
file->filedata = f9pfs;
switch ( flags & O_ACCMODE )
{
case O_RDONLY:
omode = P9_OREAD;
break;
case O_WRONLY:
omode = P9_OWRITE;
break;
case O_RDWR:
omode = P9_ORDWR;