xemu/hw/9pfs/virtio-9p-proxy.c
M. Mohan Kumar daf0b9aca9 hw/9pfs: Open and create files
Add interfaces to open and create files for proxy file system driver.

Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2012-01-04 20:14:28 +05:30

564 lines
14 KiB
C

/*
* Virtio 9p Proxy callback
*
* Copyright IBM, Corp. 2011
*
* Authors:
* M. Mohan Kumar <mohan@in.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*/
#include <sys/socket.h>
#include <sys/un.h>
#include "hw/virtio.h"
#include "virtio-9p.h"
#include "fsdev/qemu-fsdev.h"
#include "virtio-9p-proxy.h"
typedef struct V9fsProxy {
int sockfd;
QemuMutex mutex;
struct iovec iovec;
} V9fsProxy;
/*
* Return received file descriptor on success in *status.
* errno is also returned on *status (which will be < 0)
* return < 0 on transport error.
*/
static int v9fs_receivefd(int sockfd, int *status)
{
struct iovec iov;
struct msghdr msg;
struct cmsghdr *cmsg;
int retval, data, fd;
union MsgControl msg_control;
iov.iov_base = &data;
iov.iov_len = sizeof(data);
memset(&msg, 0, sizeof(msg));
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = &msg_control;
msg.msg_controllen = sizeof(msg_control);
do {
retval = recvmsg(sockfd, &msg, 0);
} while (retval < 0 && errno == EINTR);
if (retval <= 0) {
return retval;
}
/*
* data is set to V9FS_FD_VALID, if ancillary data is sent. If this
* request doesn't need ancillary data (fd) or an error occurred,
* data is set to negative errno value.
*/
if (data != V9FS_FD_VALID) {
*status = data;
return 0;
}
/*
* File descriptor (fd) is sent in the ancillary data. Check if we
* indeed received it. One of the reasons to fail to receive it is if
* we exceeded the maximum number of file descriptors!
*/
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
cmsg->cmsg_level != SOL_SOCKET ||
cmsg->cmsg_type != SCM_RIGHTS) {
continue;
}
fd = *((int *)CMSG_DATA(cmsg));
*status = fd;
return 0;
}
*status = -ENFILE; /* Ancillary data sent but not received */
return 0;
}
/*
* Proxy->header and proxy->request written to socket by QEMU process.
* This request read by proxy helper process
* returns 0 on success and -errno on error
*/
static int v9fs_request(V9fsProxy *proxy, int type,
void *response, const char *fmt, ...)
{
va_list ap;
int retval = 0;
V9fsString *path;
ProxyHeader header = { 0, 0};
struct iovec *iovec = NULL;
int flags, mode, uid, gid;
qemu_mutex_lock(&proxy->mutex);
if (proxy->sockfd == -1) {
retval = -EIO;
goto err_out;
}
iovec = &proxy->iovec;
va_start(ap, fmt);
switch (type) {
case T_OPEN:
path = va_arg(ap, V9fsString *);
flags = va_arg(ap, int);
retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sd", path, flags);
if (retval > 0) {
header.size = retval;
header.type = T_OPEN;
}
break;
case T_CREATE:
path = va_arg(ap, V9fsString *);
flags = va_arg(ap, int);
mode = va_arg(ap, int);
uid = va_arg(ap, int);
gid = va_arg(ap, int);
retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sdddd", path,
flags, mode, uid, gid);
if (retval > 0) {
header.size = retval;
header.type = T_CREATE;
}
break;
default:
error_report("Invalid type %d\n", type);
retval = -EINVAL;
break;
}
va_end(ap);
if (retval < 0) {
goto err_out;
}
/* marshal the header details */
proxy_marshal(iovec, 0, "dd", header.type, header.size);
header.size += PROXY_HDR_SZ;
retval = qemu_write_full(proxy->sockfd, iovec->iov_base, header.size);
if (retval != header.size) {
goto close_error;
}
switch (type) {
case T_OPEN:
case T_CREATE:
/*
* A file descriptor is returned as response for
* T_OPEN,T_CREATE on success
*/
if (v9fs_receivefd(proxy->sockfd, &retval) < 0) {
goto close_error;
}
break;
}
err_out:
qemu_mutex_unlock(&proxy->mutex);
return retval;
close_error:
close(proxy->sockfd);
proxy->sockfd = -1;
qemu_mutex_unlock(&proxy->mutex);
return -EIO;
}
static int proxy_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
{
errno = EOPNOTSUPP;
return -1;
}
static ssize_t proxy_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
char *buf, size_t bufsz)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_close(FsContext *ctx, V9fsFidOpenState *fs)
{
return close(fs->fd);
}
static int proxy_closedir(FsContext *ctx, V9fsFidOpenState *fs)
{
return closedir(fs->dir);
}
static int proxy_open(FsContext *ctx, V9fsPath *fs_path,
int flags, V9fsFidOpenState *fs)
{
fs->fd = v9fs_request(ctx->private, T_OPEN, NULL, "sd", fs_path, flags);
if (fs->fd < 0) {
errno = -fs->fd;
fs->fd = -1;
}
return fs->fd;
}
static int proxy_opendir(FsContext *ctx,
V9fsPath *fs_path, V9fsFidOpenState *fs)
{
int serrno, fd;
fs->dir = NULL;
fd = v9fs_request(ctx->private, T_OPEN, NULL, "sd", fs_path, O_DIRECTORY);
if (fd < 0) {
errno = -fd;
return -1;
}
fs->dir = fdopendir(fd);
if (!fs->dir) {
serrno = errno;
close(fd);
errno = serrno;
return -1;
}
return 0;
}
static void proxy_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
{
return rewinddir(fs->dir);
}
static off_t proxy_telldir(FsContext *ctx, V9fsFidOpenState *fs)
{
return telldir(fs->dir);
}
static int proxy_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
struct dirent *entry,
struct dirent **result)
{
return readdir_r(fs->dir, entry, result);
}
static void proxy_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
{
return seekdir(fs->dir, off);
}
static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
const struct iovec *iov,
int iovcnt, off_t offset)
{
#ifdef CONFIG_PREADV
return preadv(fs->fd, iov, iovcnt, offset);
#else
int err = lseek(fs->fd, offset, SEEK_SET);
if (err == -1) {
return err;
} else {
return readv(fs->fd, iov, iovcnt);
}
#endif
}
static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
const struct iovec *iov,
int iovcnt, off_t offset)
{
ssize_t ret;
#ifdef CONFIG_PREADV
ret = pwritev(fs->fd, iov, iovcnt, offset);
#else
int err = lseek(fs->fd, offset, SEEK_SET);
if (err == -1) {
return err;
} else {
ret = writev(fs->fd, iov, iovcnt);
}
#endif
#ifdef CONFIG_SYNC_FILE_RANGE
if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
/*
* Initiate a writeback. This is not a data integrity sync.
* We want to ensure that we don't leave dirty pages in the cache
* after write when writeout=immediate is sepcified.
*/
sync_file_range(fs->fd, offset, ret,
SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
}
#endif
return ret;
}
static int proxy_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
const char *name, FsCred *credp)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
const char *name, FsCred *credp)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_fstat(FsContext *fs_ctx, int fid_type,
V9fsFidOpenState *fs, struct stat *stbuf)
{
int fd;
if (fid_type == P9_FID_DIR) {
fd = dirfd(fs->dir);
} else {
fd = fs->fd;
}
return fstat(fd, stbuf);
}
static int proxy_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
int flags, FsCred *credp, V9fsFidOpenState *fs)
{
V9fsString fullname;
v9fs_string_init(&fullname);
v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
fs->fd = v9fs_request(fs_ctx->private, T_CREATE, NULL, "sdddd",
&fullname, flags, credp->fc_mode,
credp->fc_uid, credp->fc_gid);
v9fs_string_free(&fullname);
if (fs->fd < 0) {
errno = -fs->fd;
fs->fd = -1;
}
return fs->fd;
}
static int proxy_symlink(FsContext *fs_ctx, const char *oldpath,
V9fsPath *dir_path, const char *name, FsCred *credp)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_link(FsContext *ctx, V9fsPath *oldpath,
V9fsPath *dirpath, const char *name)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_rename(FsContext *ctx, const char *oldpath,
const char *newpath)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_utimensat(FsContext *s, V9fsPath *fs_path,
const struct timespec *buf)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_remove(FsContext *ctx, const char *path)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_fsync(FsContext *ctx, int fid_type,
V9fsFidOpenState *fs, int datasync)
{
int fd;
if (fid_type == P9_FID_DIR) {
fd = dirfd(fs->dir);
} else {
fd = fs->fd;
}
if (datasync) {
return qemu_fdatasync(fd);
} else {
return fsync(fd);
}
}
static int proxy_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
{
errno = EOPNOTSUPP;
return -1;
}
static ssize_t proxy_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
const char *name, void *value, size_t size)
{
errno = EOPNOTSUPP;
return -1;
}
static ssize_t proxy_llistxattr(FsContext *ctx, V9fsPath *fs_path,
void *value, size_t size)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
void *value, size_t size, int flags)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
const char *name)
{
errno = EOPNOTSUPP;
return -1;
}
static int proxy_name_to_path(FsContext *ctx, V9fsPath *dir_path,
const char *name, V9fsPath *target)
{
if (dir_path) {
v9fs_string_sprintf((V9fsString *)target, "%s/%s",
dir_path->data, name);
} else {
v9fs_string_sprintf((V9fsString *)target, "%s", name);
}
/* Bump the size for including terminating NULL */
target->size++;
return 0;
}
static int proxy_renameat(FsContext *ctx, V9fsPath *olddir,
const char *old_name, V9fsPath *newdir,
const char *new_name)
{
int ret;
V9fsString old_full_name, new_full_name;
v9fs_string_init(&old_full_name);
v9fs_string_init(&new_full_name);
v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
ret = proxy_rename(ctx, old_full_name.data, new_full_name.data);
v9fs_string_free(&old_full_name);
v9fs_string_free(&new_full_name);
return ret;
}
static int proxy_unlinkat(FsContext *ctx, V9fsPath *dir,
const char *name, int flags)
{
int ret;
V9fsString fullname;
v9fs_string_init(&fullname);
v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
ret = proxy_remove(ctx, fullname.data);
v9fs_string_free(&fullname);
return ret;
}
static int proxy_parse_opts(QemuOpts *opts, struct FsDriverEntry *fs)
{
const char *sock_fd = qemu_opt_get(opts, "sock_fd");
if (sock_fd) {
fprintf(stderr, "sock_fd option not specified\n");
return -1;
}
fs->path = g_strdup(sock_fd);
return 0;
}
static int proxy_init(FsContext *ctx)
{
V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy));
int sock_id;
sock_id = atoi(ctx->fs_root);
if (sock_id < 0) {
fprintf(stderr, "socket descriptor not initialized\n");
return -1;
}
g_free(ctx->fs_root);
proxy->iovec.iov_base = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ);
proxy->iovec.iov_len = PROXY_MAX_IO_SZ + PROXY_HDR_SZ;
ctx->private = proxy;
proxy->sockfd = sock_id;
qemu_mutex_init(&proxy->mutex);
ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
return 0;
}
FileOperations proxy_ops = {
.parse_opts = proxy_parse_opts,
.init = proxy_init,
.lstat = proxy_lstat,
.readlink = proxy_readlink,
.close = proxy_close,
.closedir = proxy_closedir,
.open = proxy_open,
.opendir = proxy_opendir,
.rewinddir = proxy_rewinddir,
.telldir = proxy_telldir,
.readdir_r = proxy_readdir_r,
.seekdir = proxy_seekdir,
.preadv = proxy_preadv,
.pwritev = proxy_pwritev,
.chmod = proxy_chmod,
.mknod = proxy_mknod,
.mkdir = proxy_mkdir,
.fstat = proxy_fstat,
.open2 = proxy_open2,
.symlink = proxy_symlink,
.link = proxy_link,
.truncate = proxy_truncate,
.rename = proxy_rename,
.chown = proxy_chown,
.utimensat = proxy_utimensat,
.remove = proxy_remove,
.fsync = proxy_fsync,
.statfs = proxy_statfs,
.lgetxattr = proxy_lgetxattr,
.llistxattr = proxy_llistxattr,
.lsetxattr = proxy_lsetxattr,
.lremovexattr = proxy_lremovexattr,
.name_to_path = proxy_name_to_path,
.renameat = proxy_renameat,
.unlinkat = proxy_unlinkat,
};