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8ad5a8c5c36add2eee70a7253da4098ebffdb79b
xen/tools/9pfsd/io.c
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Jan Beulich 8ad5a8c5c3 9pfsd: fix release build with old gcc 
Being able to recognize that "par" is reliably initialized on the 1st
loop iteration requires not overly old compilers.

Fixes: 7809132b1a ("tools/xen-9pfsd: add 9pfs response generation support")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
master commit: 984cb316cb
master date: 2024-08-02 08:44:22 +0200
2024-08-08 13:47:44 +02:00

1532 lines
37 KiB
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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* xen-9pfsd - Xen 9pfs daemon
*
* Copyright (C) 2024 Juergen Gross <jgross@suse.com>
*
* I/O thread handling.
*
* Only handle one request at a time, pushing out the complete response
* before looking for the next request.
*/
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <xenctrl.h> /* For cpu barriers. */
#include <xen-tools/common-macros.h>
#include "xen-9pfsd.h"
/* 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_OMODEMASK 0x03
#define P9_OTRUNC 0x10 /* or'ed in, truncate file first */
#define P9_OREMOVE 0x40 /* or'ed in, remove file after clunk */
/* P9 protocol create permission masks. */
#define P9_CREATE_PERM_DIR 0x80000000
#define P9_CREATE_PERM_NOTSUPP 0x03b00000 /* link, symlink, ... */
#define P9_CREATE_PERM_DIR_MASK 0777
#define P9_CREATE_PERM_FILE_MASK 0666
#define P9_MIN_MSIZE 2048
#define P9_VERSION "9P2000.u"
#define P9_WALK_MAXELEM 16
struct p9_qid {
uint8_t type;
#define QID_TYPE_DIR 0x80
uint32_t version;
uint64_t path;
};
struct p9_stat {
uint16_t size;
uint16_t type;
uint32_t dev;
struct p9_qid qid;
uint32_t mode;
uint32_t atime;
uint32_t mtime;
uint64_t length;
const char *name;
const char *uid;
const char *gid;
const char *muid;
const char *extension;
uint32_t n_uid;
uint32_t n_gid;
uint32_t n_muid;
};
/*
* Note that the ring names "in" and "out" are from the frontend's
* perspective, so the "in" ring will be used for responses to the frontend,
* while the "out" ring is used for requests from the frontend to the
* backend.
*/
static unsigned int ring_in_free(struct ring *ring)
{
unsigned int queued;
queued = xen_9pfs_queued(ring->prod_pvt_in, ring->intf->in_cons,
ring->ring_size);
xen_rmb();
return ring->ring_size - queued;
}
static unsigned int ring_out_data(struct ring *ring)
{
unsigned int queued;
queued = xen_9pfs_queued(ring->intf->out_prod, ring->cons_pvt_out,
ring->ring_size);
xen_rmb();
return queued;
}
static unsigned int get_request_bytes(struct ring *ring, unsigned int off,
unsigned int total_len)
{
unsigned int size;
unsigned int out_data = ring_out_data(ring);
RING_IDX prod, cons;
size = min(total_len - off, out_data);
prod = xen_9pfs_mask(ring->intf->out_prod, ring->ring_size);
cons = xen_9pfs_mask(ring->cons_pvt_out, ring->ring_size);
xen_9pfs_read_packet(ring->buffer + off, ring->data.out, size,
prod, &cons, ring->ring_size);
xen_rmb(); /* Read data out before setting visible consumer. */
ring->cons_pvt_out += size;
ring->intf->out_cons = ring->cons_pvt_out;
/* Signal that more space is available now. */
xenevtchn_notify(xe, ring->evtchn);
return size;
}
static unsigned int put_response_bytes(struct ring *ring, unsigned int off,
unsigned int total_len)
{
unsigned int size;
unsigned int in_data = ring_in_free(ring);
RING_IDX prod, cons;
size = min(total_len - off, in_data);
prod = xen_9pfs_mask(ring->prod_pvt_in, ring->ring_size);
cons = xen_9pfs_mask(ring->intf->in_cons, ring->ring_size);
xen_9pfs_write_packet(ring->data.in, ring->buffer + off, size,
&prod, cons, ring->ring_size);
xen_wmb(); /* Write data out before setting visible producer. */
ring->prod_pvt_in += size;
ring->intf->in_prod = ring->prod_pvt_in;
return size;
}
static bool io_work_pending(struct ring *ring)
{
if ( ring->stop_thread )
return true;
if ( ring->error )
return false;
return ring->handle_response ? ring_in_free(ring) : ring_out_data(ring);
}
static void fmt_err(const char *fmt)
{
syslog(LOG_CRIT, "illegal format %s passed to fill_buffer()", fmt);
exit(1);
}
/*
* Fill buffer with response data.
* fmt is a sequence of format characters. Supported characters are:
* a: an array (2 bytes number of elements + the following format as elements)
* The number of elements is passed in the first unsigned int parameter, the
* next parameter is a pointer to an array of elements as denoted by the next
* format character.
* b: 1 byte unsigned integer
* u: 2 byte unsigned integer
* The parameter is a pointer to a uint16_t value
* D: Data blob (4 byte length + <length> bytes)
* 2 parameters are consumed, first an unsigned int for the length, then a
* pointer to the first uint8_t value.
* No array support.
* L: 8 byte unsigned integer
* The parameter is a pointer to a uint64_t value
* Q: Qid (struct p9_qid)
* S: String (2 byte length + <length> characters)
* The length is obtained via strlen() of the parameter, being a pointer
* to the first character of the string
* s: stat (struct p9_stat)
* U: 4 byte unsigned integer
* The parameter is a pointer to a uint32_t value
*/
static void fill_buffer_at(void **data, const char *fmt, ...);
static void vfill_buffer_at(void **data, const char *fmt, va_list ap)
{
const char *f;
const void *par = NULL; /* old gcc */
const char *str_val;
const struct p9_qid *qid;
const struct p9_stat *stat;
uint16_t tlen;
unsigned int len;
unsigned int array_sz = 0;
unsigned int elem_sz = 0;
for ( f = fmt; *f; f++ )
{
if ( !array_sz )
par = va_arg(ap, const void *);
else
{
par += elem_sz;
array_sz--;
}
switch ( *f )
{
case 'a':
f++;
if ( !*f || array_sz )
fmt_err(fmt);
array_sz = *(const unsigned int *)par;
if ( array_sz > 0xffff )
{
syslog(LOG_CRIT, "array size %u in fill_buffer()", array_sz);
exit(1);
}
put_unaligned(array_sz, (uint16_t *)*data);
*data += sizeof(uint16_t);
par = va_arg(ap, const void *);
elem_sz = 0;
break;
case 'b':
put_unaligned(*(const uint8_t *)par, (uint8_t *)*data);
elem_sz = sizeof(uint8_t);
*data += sizeof(uint8_t);
break;
case 'u':
put_unaligned(*(const uint16_t *)par, (uint16_t *)*data);
elem_sz = sizeof(uint16_t);
*data += sizeof(uint16_t);
break;
case 'D':
if ( array_sz )
fmt_err(fmt);
len = *(const unsigned int *)par;
put_unaligned(len, (uint32_t *)*data);
*data += sizeof(uint32_t);
par = va_arg(ap, const void *);
if ( *data != par )
memcpy(*data, par, len);
*data += len;
break;
case 'L':
put_unaligned(*(const uint64_t *)par, (uint64_t *)*data);
elem_sz = sizeof(uint64_t);
*data += sizeof(uint64_t);
break;
case 'Q':
qid = par;
elem_sz = sizeof(*qid);
fill_buffer_at(data, "bUL", &qid->type, &qid->version, &qid->path);
break;
case 'S':
str_val = par;
elem_sz = sizeof(str_val);
len = strlen(str_val);
if ( len > 0xffff )
{
syslog(LOG_CRIT, "string length %u in fill_buffer()", len);
exit(1);
}
put_unaligned(len, (uint16_t *)*data);
*data += sizeof(uint16_t);
memcpy(*data, str_val, len);
*data += len;
break;
case 's':
stat = par;
elem_sz = sizeof(*stat);
tlen = stat->size + sizeof(stat->size);
fill_buffer_at(data, "uuuUQUUULSSSSSUUU", &tlen, &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);
break;
case 'U':
put_unaligned(*(const uint32_t *)par, (uint32_t *)*data);
elem_sz = sizeof(uint32_t);
*data += sizeof(uint32_t);
break;
default:
fmt_err(fmt);
}
if ( array_sz )
f--;
}
}
static void fill_buffer_at(void **data, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfill_buffer_at(data, fmt, ap);
va_end(ap);
}
static void fill_buffer(struct ring *ring, uint8_t cmd, uint16_t tag,
const char *fmt, ...)
{
struct p9_header *hdr = ring->buffer;
void *data = hdr + 1;
va_list ap;
hdr->cmd = cmd;
hdr->tag = tag;
va_start(ap, fmt);
vfill_buffer_at(&data, fmt, ap);
va_end(ap);
hdr->size = data - ring->buffer;
}
static unsigned int add_string(struct ring *ring, const char *str,
unsigned int len)
{
char *tmp;
unsigned int ret;
if ( ring->str_used + len + 1 > ring->str_size )
{
tmp = realloc(ring->str, ring->str_used + len + 1);
if ( !tmp )
return ~0;
ring->str = tmp;
ring->str_size = ring->str_used + len + 1;
}
ret = ring->str_used;
memcpy(ring->str + ret, str, len);
ring->str_used += len;
ring->str[ring->str_used++] = 0;
return ret;
}
static bool chk_data(struct ring *ring, void *data, unsigned int len)
{
struct p9_header *hdr = ring->buffer;
if ( data + len <= ring->buffer + hdr->size )
return true;
errno = E2BIG;
return false;
}
static bool fill_data_elem(void **par, void **array, unsigned int *array_sz,
unsigned int elem_sz, void *data)
{
if ( *array_sz && !*array )
{
*array = calloc(*array_sz, elem_sz);
if ( !*array )
return false;
*par = *array;
}
memcpy(*par, data, elem_sz);
if ( *array_sz )
{
*par += elem_sz;
*array_sz -= 1;
}
return true;
}
/*
* Fill variables with request data.
* fmt is a sequence of format characters. Supported characters are:
* a: an array (2 bytes number of elements + the following format as elements)
* The number of elements is stored in the first unsigned int parameter, the
* next parameter is a pointer to an array of elements as denoted by the next
* format character. The array is allocated dynamically.
* b: 1 byte unsigned integer
* The value is stored in the next parameter with type uint8_t.
* D: Data blob (4 byte length + <length> bytes)
* 2 parameters are consumed, first an unsigned int for the length, then a
* pointer to the first uint8_t value.
* No array support.
* L: 8 byte unsigned integer
* The value is stored in the next parameter with type uint64_t.
* S: String (2 byte length + <length> characters)
* The 0-terminated string is stored in device->str + off, off is stored in
* the next parameter with type unsigned int.
* U: 4 byte unsigned integer
* The value is stored in the next parameter with type uint32_t.
*
* Return value: number of filled variables, errno will be set in case of
* error.
*/
static int fill_data(struct ring *ring, const char *fmt, ...)
{
struct p9_header *hdr = ring->buffer;
void *data = hdr + 1;
void *par;
unsigned int pars = 0;
const char *f;
va_list ap;
unsigned int len;
unsigned int str_off;
unsigned int array_sz = 0;
void **array = NULL;
va_start(ap, fmt);
for ( f = fmt; *f; f++ )
{
if ( !array_sz )
par = va_arg(ap, void *);
switch ( *f )
{
case 'a':
f++;
if ( !*f || array_sz )
fmt_err(fmt);
if ( !chk_data(ring, data, sizeof(uint16_t)) )
goto out;
array_sz = get_unaligned((uint16_t *)data);
data += sizeof(uint16_t);
*(unsigned int *)par = array_sz;
array = va_arg(ap, void **);
*array = NULL;
break;
case 'b':
if ( !chk_data(ring, data, sizeof(uint8_t)) )
goto out;
if ( !fill_data_elem(&par, array, &array_sz, sizeof(uint8_t),
data) )
goto out;
data += sizeof(uint8_t);
break;
case 'D':
if ( array_sz )
fmt_err(fmt);
if ( !chk_data(ring, data, sizeof(uint32_t)) )
goto out;
len = get_unaligned((uint32_t *)data);
data += sizeof(uint32_t);
*(unsigned int *)par = len;
par = va_arg(ap, void *);
if ( !chk_data(ring, data, len) )
goto out;
memcpy(par, data, len);
data += len;
break;
case 'L':
if ( !chk_data(ring, data, sizeof(uint64_t)) )
goto out;
if ( !fill_data_elem(&par, array, &array_sz, sizeof(uint64_t),
data) )
goto out;
data += sizeof(uint64_t);
break;
case 'S':
if ( !chk_data(ring, data, sizeof(uint16_t)) )
goto out;
len = get_unaligned((uint16_t *)data);
data += sizeof(uint16_t);
if ( !chk_data(ring, data, len) )
goto out;
str_off = add_string(ring, data, len);
if ( str_off == ~0 )
goto out;
if ( !fill_data_elem(&par, array, &array_sz, sizeof(unsigned int),
&str_off) )
goto out;
data += len;
break;
case 'U':
if ( !chk_data(ring, data, sizeof(uint32_t)) )
goto out;
if ( !fill_data_elem(&par, array, &array_sz, sizeof(uint32_t),
data) )
goto out;
data += sizeof(uint32_t);
break;
default:
fmt_err(fmt);
}
if ( array_sz )
f--;
pars++;
}
out:
va_end(ap);
return pars;
}
static struct p9_fid *find_fid(device *device, unsigned int fid)
{
struct p9_fid *fidp;
XEN_TAILQ_FOREACH(fidp, &device->fids, list)
{
if ( fidp->fid == fid )
return fidp;
}
return NULL;
}
static struct p9_fid *get_fid_ref(device *device, unsigned int fid)
{
struct p9_fid *fidp;
pthread_mutex_lock(&device->fid_mutex);
fidp = find_fid(device, fid);
if ( fidp )
fidp->ref++;
pthread_mutex_unlock(&device->fid_mutex);
return fidp;
}
static struct p9_fid *alloc_fid_mem(device *device, unsigned int fid,
const char *path)
{
struct p9_fid *fidp;
fidp = calloc(sizeof(*fidp) + strlen(path) + 1, 1);
if ( !fidp )
return NULL;
fidp->fid = fid;
strcpy(fidp->path, path);
return fidp;
}
static struct p9_fid *alloc_fid(device *device, unsigned int fid,
const char *path)
{
struct p9_fid *fidp = NULL;
pthread_mutex_lock(&device->fid_mutex);
if ( find_fid(device, fid) )
{
errno = EBADF;
goto out;
}
if ( device->n_fids >= device->max_open_files )
{
errno = EMFILE;
goto out;
}
fidp = alloc_fid_mem(device, fid, path);
if ( !fidp )
goto out;
fidp->ref = 1;
XEN_TAILQ_INSERT_HEAD(&device->fids, fidp, list);
device->n_fids++;
out:
pthread_mutex_unlock(&device->fid_mutex);
return fidp;
}
static void free_fid(device *device, struct p9_fid *fidp)
{
if ( !fidp )
return;
pthread_mutex_lock(&device->fid_mutex);
fidp->ref--;
if ( !fidp->ref )
{
device->n_fids--;
XEN_TAILQ_REMOVE(&device->fids, fidp, list);
free(fidp);
}
pthread_mutex_unlock(&device->fid_mutex);
}
void free_fids(device *device)
{
struct p9_fid *fidp;
while ( (fidp = XEN_TAILQ_FIRST(&device->fids)) != NULL )
{
XEN_TAILQ_REMOVE(&device->fids, fidp, list);
free(fidp);
}
}
static const char *relpath_from_path(const char *path)
{
if (!strcmp(path, "/"))
return ".";
return (path[0] == '/') ? path + 1 : path;
}
static int fill_qid(device *device, const char *path, struct p9_qid *qid,
const struct stat *stbuf)
{
struct stat st;
if ( !stbuf )
{
if ( fstatat(device->root_fd, path, &st, 0) )
return errno;
stbuf = &st;
}
/* Don't allow symbolic links. */
if ( S_ISLNK(stbuf->st_mode) )
return EMLINK;
qid->type = S_ISDIR(stbuf->st_mode) ? QID_TYPE_DIR : 0;
qid->version = stbuf->st_mtime ^ (stbuf->st_size << 8);
qid->path = stbuf->st_ino;
return 0;
}
static bool name_ok(const char *str)
{
if ( !*str )
return false;
if ( strchr(str, '/' ) )
return false;
if ( !strcmp(str, "..") || !strcmp(str, ".") )
return false;
return true;
}
/* Including the '\0' */
#define MAX_ERRSTR_LEN 80
static void p9_error(struct ring *ring, uint16_t tag, uint32_t err)
{
unsigned int erroff;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
char *str;
size_t len = 0;
/*
* While strerror_r() exists, it comes in a POSIX and a GNU flavor.
* Let's try to avoid trying to be clever with determining which
* one it is that the underlying C library offers, when really we
* don't expect this function to be called very often.
*/
pthread_mutex_lock(&mutex);
str = strerror(err);
len = min(strlen(str), (size_t)(MAX_ERRSTR_LEN - 1));
memcpy(ring->buffer, str, len);
((char *)ring->buffer)[len] = '\0';
pthread_mutex_unlock(&mutex);
erroff = add_string(ring, ring->buffer, strlen(ring->buffer));
fill_buffer(ring, P9_CMD_ERROR, tag, "SU",
erroff != ~0 ? ring->str + erroff : "cannot allocate memory",
&err);
}
static void p9_version(struct ring *ring, struct p9_header *hdr)
{
uint32_t max_size;
unsigned int off;
char *version;
int ret;
ret = fill_data(ring, "US", &max_size, &off);
if ( ret != 2 )
{
p9_error(ring, hdr->tag, errno);
return;
}
if ( max_size < P9_MIN_MSIZE )
{
p9_error(ring, hdr->tag, EMSGSIZE);
return;
}
if ( max_size < ring->max_size )
ring->max_size = max_size;
version = ring->str + off;
if ( strcmp(version, P9_VERSION) )
version = "unknown";
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "US", &ring->max_size, version);
}
static void p9_attach(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
uint32_t dummy_u32;
unsigned int dummy_uint;
struct p9_qid qid;
int ret;
ret = fill_data(ring, "UUSSU", &fid, &dummy_u32, &dummy_uint, &dummy_uint,
&dummy_u32);
if ( ret != 5 )
{
p9_error(ring, hdr->tag, errno);
return;
}
device->root_fid = alloc_fid(device, fid, relpath_from_path("/"));
if ( !device->root_fid )
{
p9_error(ring, hdr->tag, errno);
return;
}
ret = fill_qid(device, device->root_fid->path, &qid, NULL);
if ( ret )
{
free_fid(device, device->root_fid);
device->root_fid = NULL;
p9_error(ring, hdr->tag, ret);
return;
}
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "Q", &qid);
}
static void p9_walk(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
uint32_t newfid;
struct p9_fid *fidp = NULL;
struct p9_qid *qids = NULL;
unsigned int n_names = 0;
unsigned int *names = NULL;
unsigned int walked = 0;
unsigned int i;
char *path = NULL;
unsigned int path_len;
int ret;
ret = fill_data(ring, "UUaS", &fid, &newfid, &n_names, &names);
if ( n_names > P9_WALK_MAXELEM )
{
p9_error(ring, hdr->tag, EINVAL);
goto out;
}
if ( ret != 3 + n_names )
{
p9_error(ring, hdr->tag, errno);
goto out;
}
fidp = get_fid_ref(device, fid);
if ( !fidp )
{
p9_error(ring, hdr->tag, ENOENT);
goto out;
}
if ( fidp->opened )
{
p9_error(ring, hdr->tag, EINVAL);
goto out;
}
path_len = strlen(fidp->path) + 1;
for ( i = 0; i < n_names; i++ )
{
if ( !name_ok(ring->str + names[i]) )
{
p9_error(ring, hdr->tag, ENOENT);
goto out;
}
path_len += strlen(ring->str + names[i]) + 1;
}
path = calloc(path_len + 1, 1);
if ( !path )
{
p9_error(ring, hdr->tag, ENOMEM);
goto out;
}
strcpy(path, fidp->path);
if ( n_names )
{
qids = calloc(n_names, sizeof(*qids));
if ( !qids )
{
p9_error(ring, hdr->tag, ENOMEM);
goto out;
}
for ( i = 0; i < n_names; i++ )
{
strcat(path, "/");
strcat(path, ring->str + names[i]);
ret = fill_qid(device, path, qids + i, NULL);
if ( ret )
{
if ( !walked )
{
p9_error(ring, hdr->tag, errno);
goto out;
}
break;
}
walked++;
}
}
if ( walked == n_names )
{
bool ok = false;
if ( fid == newfid )
{
struct p9_fid *new_fidp;
pthread_mutex_lock(&device->fid_mutex);
if ( fidp->ref != 2 )
{
errno = EBUSY;
}
else
{
new_fidp = alloc_fid_mem(device, fid, path);
if ( new_fidp )
{
new_fidp->ref = 2;
XEN_TAILQ_REMOVE(&device->fids, fidp, list);
XEN_TAILQ_INSERT_HEAD(&device->fids, new_fidp, list);
free(fidp);
fidp = new_fidp;
ok = true;
}
}
pthread_mutex_unlock(&device->fid_mutex);
}
else
ok = alloc_fid(device, newfid, path);
if ( !ok )
{
p9_error(ring, hdr->tag, errno);
goto out;
}
}
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "aQ", &walked, qids);
out:
free_fid(device, fidp);
free(qids);
free(path);
free(names);
}
static int open_flags_from_mode(uint8_t mode)
{
int flags;
switch ( mode & P9_OMODEMASK )
{
case P9_OREAD:
flags = O_RDONLY;
break;
case P9_OWRITE:
flags = O_WRONLY;
break;
case P9_ORDWR:
flags = O_RDWR;
break;
default:
errno = EINVAL;
return -1;
}
if ( mode & P9_OTRUNC )
flags |= O_TRUNC;
return flags;
}
static unsigned int get_iounit(struct ring *ring, struct stat *st)
{
return (ring->max_size - st->st_blksize) & ~(st->st_blksize - 1);
}
static void p9_open(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
uint8_t mode;
struct p9_fid *fidp;
struct stat st;
struct p9_qid qid;
uint32_t iounit;
int flags;
int ret;
ret = fill_data(ring, "Ub", &fid, &mode);
if ( ret != 2 )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
if ( mode & ~(P9_OMODEMASK | P9_OTRUNC | P9_OREMOVE) )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
fidp = get_fid_ref(device, fid);
if ( !fidp )
{
p9_error(ring, hdr->tag, ENOENT);
return;
}
if ( fidp->opened )
{
errno = EINVAL;
goto err;
}
if ( fstatat(device->root_fd, fidp->path, &st, 0) < 0 )
{
errno = ENOENT;
goto err;
}
if ( S_ISLNK(st.st_mode) )
{
errno = EMLINK;
goto err;
}
fidp->isdir = S_ISDIR(st.st_mode);
fidp->mode = mode;
if ( fidp->isdir )
{
if ( mode != P9_OREAD )
{
errno = EINVAL;
goto err;
}
fidp->fd = openat(device->root_fd, fidp->path, O_RDONLY);
if ( fidp->fd < 0 )
goto err;
fidp->data = fdopendir(fidp->fd);
if ( !fidp->data )
goto err;
}
else
{
flags = open_flags_from_mode(mode);
if ( flags < 0 )
goto err;
fidp->fd = openat(device->root_fd, fidp->path, flags);
if ( fidp->fd < 0 )
goto err;
}
fill_qid(device, fidp->path, &qid, &st);
iounit = get_iounit(ring, &st);
fidp->opened = true;
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "QU", &qid, &iounit);
return;
err:
free_fid(device, fidp);
p9_error(ring, hdr->tag, errno);
}
static void p9_create(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
unsigned int name_off;
uint32_t perm;
uint8_t mode;
unsigned int ext_off;
struct p9_fid *fidp;
struct p9_fid *new_fidp;
char *path;
struct stat st;
struct p9_qid qid;
uint32_t iounit;
int flags;
int ret;
ret = fill_data(ring, "USUbS", &fid, &name_off, &perm, &mode, &ext_off);
if ( ret != 5 )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
if ( !name_ok(ring->str + name_off) )
{
p9_error(ring, hdr->tag, ENOENT);
return;
}
if ( perm & P9_CREATE_PERM_NOTSUPP )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
fidp = get_fid_ref(device, fid);
if ( !fidp || fidp->opened )
{
free_fid(device, fidp);
p9_error(ring, hdr->tag, EINVAL);
return;
}
if ( fstatat(device->root_fd, fidp->path, &st, 0) < 0 )
{
free_fid(device, fidp);
p9_error(ring, hdr->tag, errno);
return;
}
path = malloc(strlen(fidp->path) + strlen(ring->str + name_off) + 2);
if ( !path )
{
free_fid(device, fidp);
p9_error(ring, hdr->tag, ENOMEM);
return;
}
sprintf(path, "%s/%s", fidp->path, ring->str + name_off);
new_fidp = alloc_fid_mem(device, fid, path);
free(path);
if ( !new_fidp )
{
free_fid(device, fidp);
p9_error(ring, hdr->tag, ENOMEM);
return;
}
pthread_mutex_lock(&device->fid_mutex);
new_fidp->ref = fidp->ref;
if ( perm & P9_CREATE_PERM_DIR )
{
perm &= P9_CREATE_PERM_DIR_MASK & st.st_mode;
if ( mode != P9_OREAD )
{
errno = EINVAL;
goto err;
}
if ( mkdirat(device->root_fd, new_fidp->path, perm) < 0 )
goto err;
XEN_TAILQ_REMOVE(&device->fids, fidp, list);
XEN_TAILQ_INSERT_HEAD(&device->fids, new_fidp, list);
free(fidp);
fidp = new_fidp;
new_fidp = NULL;
fidp->fd = openat(device->root_fd, fidp->path, O_RDONLY);
if ( fidp->fd < 0 )
goto err;
fidp->data = fdopendir(fidp->fd);
if ( !fidp->data )
goto err;
}
else
{
flags = open_flags_from_mode(mode);
if ( flags < 0 )
{
errno = EINVAL;
goto err;
}
perm &= P9_CREATE_PERM_FILE_MASK & st.st_mode;
XEN_TAILQ_REMOVE(&device->fids, fidp, list);
XEN_TAILQ_INSERT_HEAD(&device->fids, new_fidp, list);
free(fidp);
fidp = new_fidp;
new_fidp = NULL;
fidp->fd = openat(device->root_fd, fidp->path, flags | O_CREAT | O_EXCL,
perm);
if ( fidp->fd < 0 )
goto err;
}
if ( fstatat(device->root_fd, fidp->path, &st, 0) < 0 )
goto err;
fill_qid(device, fidp->path, &qid, &st);
iounit = get_iounit(ring, &st);
fidp->opened = true;
fidp->mode = mode;
pthread_mutex_unlock(&device->fid_mutex);
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "QU", &qid, &iounit);
return;
err:
p9_error(ring, hdr->tag, errno);
pthread_mutex_unlock(&device->fid_mutex);
free(new_fidp);
free_fid(device, fidp);
}
static void p9_clunk(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
struct p9_fid *fidp;
int ret;
ret = fill_data(ring, "U", &fid);
if ( ret != 1 )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
fidp = get_fid_ref(device, fid);
if ( !fidp )
{
p9_error(ring, hdr->tag, ENOENT);
return;
}
if ( fidp->opened )
{
fidp->opened = false;
free_fid(device, fidp);
close(fidp->fd);
if ( fidp->mode & P9_OREMOVE )
unlinkat(device->root_fd, fidp->path,
fidp->isdir ? AT_REMOVEDIR : 0);
}
/* 2 calls of free_fid(): one for our reference, and one to free it. */
free_fid(device, fidp);
free_fid(device, fidp);
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "");
}
static void fill_p9_stat(device *device, struct p9_stat *p9s, struct stat *st,
const char *name)
{
memset(p9s, 0, sizeof(*p9s));
fill_qid(device, NULL, &p9s->qid, st);
p9s->mode = st->st_mode & 0777;
if ( S_ISDIR(st->st_mode) )
p9s->mode |= P9_CREATE_PERM_DIR;
p9s->atime = st->st_atime;
p9s->mtime = st->st_mtime;
p9s->length = st->st_size;
p9s->name = name;
p9s->uid = "";
p9s->gid = "";
p9s->muid = "";
p9s->extension = "";
p9s->n_uid = 0;
p9s->n_gid = 0;
p9s->n_muid = 0;
/*
* Size of individual fields without the size field, including 5 2-byte
* string length fields.
*/
p9s->size = 71 + strlen(p9s->name);
}
static void p9_stat(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
struct p9_fid *fidp;
struct p9_stat p9s;
struct stat st;
int ret;
ret = fill_data(ring, "U", &fid);
if ( ret != 1 )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
fidp = get_fid_ref(device, fid);
if ( !fidp )
{
p9_error(ring, hdr->tag, ENOENT);
return;
}
if ( fstatat(device->root_fd, fidp->path, &st, 0) < 0 )
{
p9_error(ring, hdr->tag, errno);
goto out;
}
fill_p9_stat(device, &p9s, &st, strrchr(fidp->path, '/') + 1);
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "s", &p9s);
out:
free_fid(device, fidp);
}
static void p9_read(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
uint64_t off;
unsigned int len;
uint32_t count;
void *buf;
struct p9_fid *fidp;
int ret;
ret = fill_data(ring, "ULU", &fid, &off, &count);
if ( ret != 3 )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
fidp = get_fid_ref(device, fid);
if ( !fidp || !fidp->opened )
{
errno = EBADF;
goto err;
}
len = count;
buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t);
if ( fidp->isdir )
{
struct dirent *dirent;
struct stat st;
struct p9_stat p9s;
if ( off == 0 )
rewinddir(fidp->data);
while ( len != 0 )
{
errno = 0;
dirent = readdir(fidp->data);
if ( !dirent )
{
if ( errno )
goto err;
break;
}
if ( fstatat(fidp->fd, dirent->d_name, &st, 0) < 0 )
goto err;
fill_p9_stat(device, &p9s, &st, dirent->d_name);
if ( p9s.size + sizeof(p9s.size) > len )
{
seekdir(fidp->data, dirent->d_off);
break;
}
fill_buffer_at(&buf, "s", &p9s);
len -= p9s.size + sizeof(p9s.size);
}
}
else
{
while ( len != 0 )
{
ret = pread(fidp->fd, buf, len, off);
if ( ret <= 0 )
break;
len -= ret;
buf += ret;
off += ret;
}
if ( ret < 0 && len == count )
goto err;
}
buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t);
len = count - len;
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "D", &len, buf);
out:
free_fid(device, fidp);
return;
err:
p9_error(ring, hdr->tag, errno);
goto out;
}
static void p9_write(struct ring *ring, struct p9_header *hdr)
{
device *device = ring->device;
uint32_t fid;
uint64_t off;
unsigned int len;
uint32_t written;
void *buf;
struct p9_fid *fidp;
int ret;
ret = fill_data(ring, "ULD", &fid, &off, &len, ring->buffer);
if ( ret != 3 )
{
p9_error(ring, hdr->tag, EINVAL);
return;
}
fidp = get_fid_ref(device, fid);
if ( !fidp || !fidp->opened || fidp->isdir )
{
p9_error(ring, hdr->tag, EBADF);
goto out;
}
buf = ring->buffer;
while ( len != 0 )
{
ret = pwrite(fidp->fd, buf, len, off);
if ( ret < 0 )
break;
len -= ret;
buf += ret;
off += ret;
}
written = buf - ring->buffer;
if ( written == 0 )
{
p9_error(ring, hdr->tag, errno);
goto out;
}
fill_buffer(ring, hdr->cmd + 1, hdr->tag, "U", &written);
out:
free_fid(device, fidp);
}
void *io_thread(void *arg)
{
struct ring *ring = arg;
unsigned int count = 0;
struct p9_header hdr = { .size = 0 };
bool in_hdr = true;
ring->max_size = ring->ring_size;
ring->buffer = malloc(ring->max_size);
if ( !ring->buffer )
{
syslog(LOG_CRIT, "memory allocation failure!");
return NULL;
}
while ( !ring->stop_thread )
{
pthread_mutex_lock(&ring->mutex);
if ( !io_work_pending(ring) )
{
if ( !ring->error && xenevtchn_unmask(xe, ring->evtchn) < 0 )
syslog(LOG_WARNING, "xenevtchn_unmask() failed");
pthread_cond_wait(&ring->cond, &ring->mutex);
}
pthread_mutex_unlock(&ring->mutex);
if ( ring->stop_thread || ring->error )
continue;
if ( !ring->handle_response )
{
if ( in_hdr )
{
count += get_request_bytes(ring, count, sizeof(hdr));
if ( count != sizeof(hdr) )
continue;
hdr = *(struct p9_header *)ring->buffer;
if ( hdr.size > ring->max_size || hdr.size < sizeof(hdr) )
{
syslog(LOG_ERR, "%u.%u specified illegal request length %u",
ring->device->domid, ring->device->devid, hdr.size);
ring->error = true;
continue;
}
in_hdr = false;
}
count += get_request_bytes(ring, count, hdr.size);
if ( count < hdr.size )
continue;
ring->str_used = 0;
switch ( hdr.cmd )
{
case P9_CMD_VERSION:
p9_version(ring, &hdr);
break;
case P9_CMD_ATTACH:
p9_attach(ring, &hdr);
break;
case P9_CMD_WALK:
p9_walk(ring, &hdr);
break;
case P9_CMD_OPEN:
p9_open(ring, &hdr);
break;
case P9_CMD_CREATE:
p9_create(ring, &hdr);
break;
case P9_CMD_READ:
p9_read(ring, &hdr);
break;
case P9_CMD_WRITE:
p9_write(ring, &hdr);
break;
case P9_CMD_CLUNK:
p9_clunk(ring, &hdr);
break;
case P9_CMD_STAT:
p9_stat(ring, &hdr);
break;
default:
syslog(LOG_DEBUG, "%u.%u sent unhandled command %u\n",
ring->device->domid, ring->device->devid, hdr.cmd);
p9_error(ring, hdr.tag, EOPNOTSUPP);
break;
}
ring->handle_response = true;
hdr.size = ((struct p9_header *)ring->buffer)->size;
count = 0;
}
if ( ring->handle_response )
{
count += put_response_bytes(ring, count, hdr.size);
if ( count == hdr.size )
{
/* Signal presence of response. */
xenevtchn_notify(xe, ring->evtchn);
ring->handle_response = false;
in_hdr = true;
count = 0;
}
}
}
free(ring->str);
free(ring->buffer);
ring->thread_active = false;
return NULL;
}
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