[Qemu-devel] [PATCH 8/8] hw/9pfs: Add handle based fs driver

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <address@hidden>
---
 Makefile.objs              |    8 +-
 fsdev/qemu-fsdev.c         |    1 +
 fsdev/qemu-fsdev.h         |    1 +
 hw/9pfs/virtio-9p-handle.c |  611 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 617 insertions(+), 4 deletions(-)
 create mode 100644 hw/9pfs/virtio-9p-handle.c

diff --git a/Makefile.objs b/Makefile.objs
index 26b885b..d315d01 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -302,11 +302,11 @@ sound-obj-$(CONFIG_HDA) += intel-hda.o hda-audio.o
 adlib.o fmopl.o: QEMU_CFLAGS += -DBUILD_Y8950=0
 hw-obj-$(CONFIG_SOUND) += $(sound-obj-y)
 
-9pfs-nested-$(CONFIG_VIRTFS) = virtio-9p.o virtio-9p-debug.o
-9pfs-nested-$(CONFIG_VIRTFS) +=  virtio-9p-local.o virtio-9p-xattr.o
-9pfs-nested-$(CONFIG_VIRTFS) +=   virtio-9p-xattr-user.o virtio-9p-posix-acl.o
+9pfs-nested-$(CONFIG_VIRTFS)  = virtio-9p.o virtio-9p-debug.o
+9pfs-nested-$(CONFIG_VIRTFS) += virtio-9p-local.o virtio-9p-xattr.o
+9pfs-nested-$(CONFIG_VIRTFS) += virtio-9p-xattr-user.o virtio-9p-posix-acl.o
 9pfs-nested-$(CONFIG_VIRTFS) += virtio-9p-coth.o cofs.o codir.o cofile.o
-9pfs-nested-$(CONFIG_VIRTFS) += coxattr.o
+9pfs-nested-$(CONFIG_VIRTFS) += coxattr.o virtio-9p-handle.o
 
 hw-obj-$(CONFIG_REALLY_VIRTFS) += $(addprefix 9pfs/, $(9pfs-nested-y))
 $(addprefix 9pfs/, $(9pfs-nested-y)): QEMU_CFLAGS+=$(GLIB_CFLAGS)
diff --git a/fsdev/qemu-fsdev.c b/fsdev/qemu-fsdev.c
index 336d7e4..768819f 100644
--- a/fsdev/qemu-fsdev.c
+++ b/fsdev/qemu-fsdev.c
@@ -23,6 +23,7 @@ static QTAILQ_HEAD(FsTypeEntry_head, FsTypeListEntry) 
fstype_entries =
 
 static FsTypeTable FsTypes[] = {
     { .name = "local", .ops = &local_ops},
+    { .name = "handle", .ops = &handle_ops},
 };
 
 int qemu_fsdev_add(QemuOpts *opts)
diff --git a/fsdev/qemu-fsdev.h b/fsdev/qemu-fsdev.h
index f9f08d3..e04931a 100644
--- a/fsdev/qemu-fsdev.h
+++ b/fsdev/qemu-fsdev.h
@@ -52,4 +52,5 @@ typedef struct FsTypeListEntry {
 int qemu_fsdev_add(QemuOpts *opts);
 FsTypeEntry *get_fsdev_fsentry(char *id);
 extern FileOperations local_ops;
+extern FileOperations handle_ops;
 #endif
diff --git a/hw/9pfs/virtio-9p-handle.c b/hw/9pfs/virtio-9p-handle.c
new file mode 100644
index 0000000..5c8b5ed
--- /dev/null
+++ b/hw/9pfs/virtio-9p-handle.c
@@ -0,0 +1,611 @@
+/*
+ * Virtio 9p handle callback
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *    Aneesh Kumar K.V <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "hw/virtio.h"
+#include "virtio-9p.h"
+#include "virtio-9p-xattr.h"
+#include <arpa/inet.h>
+#include <pwd.h>
+#include <grp.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <attr/xattr.h>
+#include <unistd.h>
+
+struct handle_data {
+    int mountfd;
+    int handle_bytes;
+};
+
+#if __GLIBC__ <= 2 && __GLIBC_MINOR__ < 14
+struct file_handle {
+        unsigned int handle_bytes;
+        int handle_type;
+        unsigned char handle[0];
+};
+#endif
+
+#ifndef AT_EMPTY_PATH
+#define AT_EMPTY_PATH   0x1000  /* Allow empty relative pathname */
+#endif
+#ifndef O_PATH
+#define O_PATH    010000000
+#endif
+
+#ifndef __NR_name_to_handle_at
+#if defined(__i386__)
+#define __NR_name_to_handle_at  341
+#define __NR_open_by_handle_at  342
+#elif defined(__x86_64__)
+#define __NR_name_to_handle_at  303
+#define __NR_open_by_handle_at  304
+#endif
+#endif
+
+#ifdef __NR_name_to_handle_at
+static inline int name_to_handle(int dirfd, const char *name,
+                                 struct file_handle *fh, int *mnt_id, int 
flags)
+{
+    return syscall(__NR_name_to_handle_at, dirfd, name, fh, mnt_id, flags);
+}
+
+static inline int open_by_handle(int mountfd, const char *fh, int flags)
+{
+    return syscall(__NR_open_by_handle_at, mountfd, fh, flags);
+}
+#else
+static inline int name_to_handle(int dirfd, const char *name,
+                                 struct file_handle *fh, int *mnt_id, int 
flags)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
+static inline int open_by_handle(int mountfd, const char *fh, int flags)
+{
+    errno = ENOSYS;
+    return -1;
+}
+#endif
+
+static int handle_update_file_cred(int dirfd, const char *name, FsCred *credp)
+{
+    int fd, ret;
+    fd = openat(dirfd, name, O_NONBLOCK | O_NOFOLLOW);;
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fchmod(fd, credp->fc_mode & 07777);
+    if (ret < 0) {
+        goto err_out;
+    }
+    ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
+err_out:
+    close(fd);
+    return ret;
+}
+
+
+static int handle_lstat(FsContext *fs_ctx, V9fsPath *fs_path,
+                        struct stat *stbuf)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fstatat(fd, "", stbuf, AT_EMPTY_PATH);
+    close(fd);
+    return ret;
+}
+
+static ssize_t handle_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
+                               char *buf, size_t bufsz)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = readlinkat(fd, "", buf, bufsz);
+    close(fd);
+    return ret;
+}
+
+static int handle_close(FsContext *ctx, int fd)
+{
+    return close(fd);
+}
+
+static int handle_closedir(FsContext *ctx, DIR *dir)
+{
+    return closedir(dir);
+}
+
+static int handle_open(FsContext *ctx, V9fsPath *fs_path, int flags)
+{
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    return open_by_handle(data->mountfd, fs_path->data, flags);
+}
+
+static DIR *handle_opendir(FsContext *ctx, V9fsPath *fs_path)
+{
+    int fd;
+    fd = handle_open(ctx, fs_path, O_DIRECTORY);
+    if (fd < 0) {
+        return NULL;
+    }
+    return fdopendir(fd);
+}
+
+static void handle_rewinddir(FsContext *ctx, DIR *dir)
+{
+    return rewinddir(dir);
+}
+
+static off_t handle_telldir(FsContext *ctx, DIR *dir)
+{
+    return telldir(dir);
+}
+
+static int handle_readdir_r(FsContext *ctx, DIR *dir, struct dirent *entry,
+                            struct dirent **result)
+{
+    return readdir_r(dir, entry, result);
+}
+
+static void handle_seekdir(FsContext *ctx, DIR *dir, off_t off)
+{
+    return seekdir(dir, off);
+}
+
+static ssize_t handle_preadv(FsContext *ctx, int fd, const struct iovec *iov,
+                             int iovcnt, off_t offset)
+{
+#ifdef CONFIG_PREADV
+    return preadv(fd, iov, iovcnt, offset);
+#else
+    int err = lseek(fd, offset, SEEK_SET);
+    if (err == -1) {
+        return err;
+    } else {
+        return readv(fd, iov, iovcnt);
+    }
+#endif
+}
+
+static ssize_t handle_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
+                              int iovcnt, off_t offset)
+{
+#ifdef CONFIG_PREADV
+    return pwritev(fd, iov, iovcnt, offset);
+#else
+    int err = lseek(fd, offset, SEEK_SET);
+    if (err == -1) {
+        return err;
+    } else {
+        return writev(fd, iov, iovcnt);
+    }
+#endif
+}
+
+static int handle_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fchmod(fd, credp->fc_mode);
+    close(fd);
+    return ret;
+}
+
+static int handle_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
+                       const char *name, FsCred *credp)
+{
+    int dirfd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
+    if (dirfd < 0) {
+        return dirfd;
+    }
+    ret = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
+    if (!ret) {
+        ret = handle_update_file_cred(dirfd, name, credp);
+    }
+    close(dirfd);
+    return ret;
+}
+
+static int handle_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
+                       const char *name, FsCred *credp)
+{
+    int dirfd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
+    if (dirfd < 0) {
+        return dirfd;
+    }
+    ret = mkdirat(dirfd, name, credp->fc_mode);
+    if (!ret) {
+        ret = handle_update_file_cred(dirfd, name, credp);
+    }
+    close(dirfd);
+    return ret;
+}
+
+static int handle_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
+{
+    return fstat(fd, stbuf);
+}
+
+static int handle_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char 
*name,
+                       int flags, FsCred *credp)
+{
+    int ret;
+    int dirfd, fd;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
+    if (dirfd < 0) {
+        return dirfd;
+    }
+    fd = openat(dirfd, name, flags | O_NOFOLLOW, credp->fc_mode);
+    if (fd >= 0) {
+        ret = handle_update_file_cred(dirfd, name, credp);
+        if (ret < 0) {
+            close(fd);
+            fd = ret;
+        }
+    }
+    close(dirfd);
+    return fd;
+}
+
+
+static int handle_symlink(FsContext *fs_ctx, const char *oldpath,
+                          V9fsPath *dir_path, const char *name, FsCred *credp)
+{
+    int fd, dirfd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
+    if (dirfd < 0) {
+        return dirfd;
+    }
+    ret = symlinkat(oldpath, dirfd, name);
+    if (!ret) {
+        fd = openat(dirfd, name, O_PATH | O_NOFOLLOW);
+        if (fd < 0) {
+            ret = fd;
+            goto err_out;
+        }
+        ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
+        close(fd);
+    }
+err_out:
+    close(dirfd);
+    return ret;
+}
+
+static int handle_link(FsContext *ctx, V9fsPath *oldpath,
+                       V9fsPath *dirpath, const char *name)
+{
+    int oldfd, newdirfd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    oldfd = open_by_handle(data->mountfd, oldpath->data, O_PATH);
+    if (oldfd < 0) {
+        return oldfd;
+    }
+    newdirfd = open_by_handle(data->mountfd, dirpath->data, O_PATH);
+    if (newdirfd < 0) {
+        close(oldfd);
+        return newdirfd;
+    }
+    ret = linkat(oldfd, "", newdirfd, name, AT_EMPTY_PATH);
+    close(newdirfd);
+    close(oldfd);
+    return ret;
+}
+
+static int handle_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK | O_WRONLY);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = ftruncate(fd, size);
+    close(fd);
+    return ret;
+}
+
+static int handle_rename(FsContext *ctx, const char *oldpath,
+                         const char *newpath)
+{
+    errno = EOPNOTSUPP;
+    return -1;
+}
+
+static int handle_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)fs_ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
+    close(fd);
+    return ret;
+}
+
+static int handle_utimensat(FsContext *ctx, V9fsPath *fs_path,
+                            const struct timespec *buf)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = futimens(fd, buf);
+    close(fd);
+    return ret;
+}
+
+static int handle_remove(FsContext *ctx, const char *path)
+{
+    errno = EOPNOTSUPP;
+    return -1;
+}
+
+static int handle_fsync(FsContext *ctx, int fd, int datasync)
+{
+    if (datasync) {
+        return qemu_fdatasync(fd);
+    } else {
+        return fsync(fd);
+    }
+}
+
+static int handle_statfs(FsContext *ctx, V9fsPath *fs_path,
+                         struct statfs *stbuf)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fstatfs(fd, stbuf);
+    close(fd);
+    return ret;
+}
+
+static ssize_t handle_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
+                                const char *name, void *value, size_t size)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fgetxattr(fd, name, value, size);
+    close(fd);
+    return ret;
+}
+
+static ssize_t handle_llistxattr(FsContext *ctx, V9fsPath *fs_path,
+                                 void *value, size_t size)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = flistxattr(fd, value, size);
+    close(fd);
+    return ret;
+}
+
+static int handle_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char 
*name,
+                            void *value, size_t size, int flags)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fsetxattr(fd, name, value, size, flags);
+    close(fd);
+    return ret;
+}
+
+static int handle_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
+                               const char *name)
+{
+    int fd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
+    if (fd < 0) {
+        return fd;
+    }
+    ret = fremovexattr(fd, name);
+    close(fd);
+    return ret;
+}
+
+static int handle_name_to_path(FsContext *ctx, V9fsPath *dir_path,
+                              const char *name, V9fsPath *target)
+{
+    char buffer[PATH_MAX];
+    struct file_handle *fh;
+    int dirfd, ret, mnt_id;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    /* "." and ".." are not allowed */
+    if (!strcmp(name, ".") || !strcmp(name, "..")) {
+        errno = EINVAL;
+        return -1;
+
+    }
+    if (dir_path) {
+        dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
+    } else {
+        /* relative to export root */
+        dirfd = open(rpath(ctx, ".", buffer), O_DIRECTORY);
+    }
+    if (dirfd < 0) {
+        return dirfd;
+    }
+    fh = g_malloc(sizeof(struct file_handle) + data->handle_bytes);
+    fh->handle_bytes = data->handle_bytes;
+    /* add a "./" at the begining of the path */
+    snprintf(buffer, PATH_MAX, "./%s", name);
+    /* flag = 0 imply don't follow symlink */
+    ret = name_to_handle(dirfd, buffer, fh, &mnt_id, 0);
+    if (!ret) {
+        target->data = (char *)fh;
+        target->size = sizeof(struct file_handle) + data->handle_bytes;
+    } else {
+        g_free(fh);
+    }
+    close(dirfd);
+    return ret;
+}
+
+static int handle_renameat(FsContext *ctx, V9fsPath *olddir,
+                           const char *old_name, V9fsPath *newdir,
+                           const char *new_name)
+{
+    int olddirfd, newdirfd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    olddirfd = open_by_handle(data->mountfd, olddir->data, O_PATH);
+    if (olddirfd < 0) {
+        return olddirfd;
+    }
+    newdirfd = open_by_handle(data->mountfd, newdir->data, O_PATH);
+    if (newdirfd < 0) {
+        close(olddirfd);
+        return newdirfd;
+    }
+    ret = renameat(olddirfd, old_name, newdirfd, new_name);
+    close(newdirfd);
+    close(olddirfd);
+    return ret;
+}
+
+static int handle_unlinkat(FsContext *ctx, V9fsPath *dir,
+                           const char *name, int flags)
+{
+    int dirfd, ret;
+    struct handle_data *data = (struct handle_data *)ctx->private;
+
+    dirfd = open_by_handle(data->mountfd, dir->data, O_PATH);
+    if (dirfd < 0) {
+        return dirfd;
+    }
+
+    ret = unlinkat(dirfd, name, flags);
+    close(dirfd);
+    return ret;
+}
+
+static int handle_init(FsContext *ctx)
+{
+    int ret, mnt_id;
+    struct file_handle fh;
+    struct handle_data *data = g_malloc(sizeof(struct handle_data));
+    data->mountfd = open(ctx->fs_root, O_DIRECTORY);
+    if (data->mountfd < 0) {
+        ret = data->mountfd;
+        goto err_out;
+    }
+    memset(&fh, 0, sizeof(struct file_handle));
+    ret = name_to_handle(data->mountfd, ".", &fh, &mnt_id, 0);
+    if (ret && errno == EOVERFLOW) {
+        data->handle_bytes = fh.handle_bytes;
+        ctx->private = data;
+        ret = 0;
+        goto out;
+    }
+    /* we got 0 byte handle ? */
+    ret = -1;
+    close(data->mountfd);
+err_out:
+    g_free(data);
+out:
+    return ret;
+}
+
+FileOperations handle_ops = {
+    .init         = handle_init,
+    .lstat        = handle_lstat,
+    .readlink     = handle_readlink,
+    .close        = handle_close,
+    .closedir     = handle_closedir,
+    .open         = handle_open,
+    .opendir      = handle_opendir,
+    .rewinddir    = handle_rewinddir,
+    .telldir      = handle_telldir,
+    .readdir_r    = handle_readdir_r,
+    .seekdir      = handle_seekdir,
+    .preadv       = handle_preadv,
+    .pwritev      = handle_pwritev,
+    .chmod        = handle_chmod,
+    .mknod        = handle_mknod,
+    .mkdir        = handle_mkdir,
+    .fstat        = handle_fstat,
+    .open2        = handle_open2,
+    .symlink      = handle_symlink,
+    .link         = handle_link,
+    .truncate     = handle_truncate,
+    .rename       = handle_rename,
+    .chown        = handle_chown,
+    .utimensat    = handle_utimensat,
+    .remove       = handle_remove,
+    .fsync        = handle_fsync,
+    .statfs       = handle_statfs,
+    .lgetxattr    = handle_lgetxattr,
+    .llistxattr   = handle_llistxattr,
+    .lsetxattr    = handle_lsetxattr,
+    .lremovexattr = handle_lremovexattr,
+    .name_to_path = handle_name_to_path,
+    .renameat     = handle_renameat,
+    .unlinkat     = handle_unlinkat,
+};
-- 
1.7.4.1