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authorM. Mohan Kumar <mohan@in.ibm.com>2011-12-14 13:58:44 +0530
committerAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2012-01-04 20:14:28 +0530
commitdaf0b9aca9f67323266af1a92e8ea06f9d7bf408 (patch)
tree6c66baf222b8efb19a1dab88334add4d9275d96c /hw/9pfs
parent17bff52b6225419931703aa04cc454c16cf5adad (diff)
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>
Diffstat (limited to 'hw/9pfs')
-rw-r--r--hw/9pfs/virtio-9p-proxy.c187
-rw-r--r--hw/9pfs/virtio-9p-proxy.h11
2 files changed, 192 insertions, 6 deletions
diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
index 3e4dc68d34..9399c66c6d 100644
--- a/hw/9pfs/virtio-9p-proxy.c
+++ b/hw/9pfs/virtio-9p-proxy.c
@@ -22,6 +22,153 @@ typedef struct V9fsProxy {
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;
@@ -48,16 +195,33 @@ static int proxy_closedir(FsContext *ctx, V9fsFidOpenState *fs)
static int proxy_open(FsContext *ctx, V9fsPath *fs_path,
int flags, V9fsFidOpenState *fs)
{
- fs->fd = -1;
+ 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;
- errno = EOPNOTSUPP;
- return -1;
+ 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)
@@ -164,9 +328,20 @@ static int proxy_fstat(FsContext *fs_ctx, int fid_type,
static int proxy_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
int flags, FsCred *credp, V9fsFidOpenState *fs)
{
- fs->fd = -1;
- errno = EOPNOTSUPP;
- return -1;
+ 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;
}
diff --git a/hw/9pfs/virtio-9p-proxy.h b/hw/9pfs/virtio-9p-proxy.h
index 97c5574de6..6172e5faba 100644
--- a/hw/9pfs/virtio-9p-proxy.h
+++ b/hw/9pfs/virtio-9p-proxy.h
@@ -13,6 +13,7 @@
#define _QEMU_VIRTIO_9P_PROXY_H
#define PROXY_MAX_IO_SZ (64 * 1024)
+#define V9FS_FD_VALID INT_MAX
/*
* proxy iovec only support one element and
@@ -23,6 +24,11 @@
#define proxy_marshal(out_sg, offset, fmt, args...) \
v9fs_marshal(out_sg, 1, offset, 0, fmt, ##args)
+union MsgControl {
+ struct cmsghdr cmsg;
+ char control[CMSG_SPACE(sizeof(int))];
+};
+
typedef struct {
uint32_t type;
uint32_t size;
@@ -30,4 +36,9 @@ typedef struct {
#define PROXY_HDR_SZ (sizeof(ProxyHeader))
+enum {
+ T_OPEN = 1,
+ T_CREATE,
+};
+
#endif