Archipelago » qemu

/*

 * Virtio 9p synthetic file system support

 *

 * Copyright IBM, Corp. 2011

 *

 * Authors:

 *  Malahal Naineni <malahal@us.ibm.com>

 *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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 "hw/virtio/virtio.h"

#include "virtio-9p.h"

#include "virtio-9p-xattr.h"

#include "fsdev/qemu-fsdev.h"

#include "virtio-9p-synth.h"

#include <sys/stat.h>

/* Root node for synth file system */

V9fsSynthNode v9fs_synth_root = {

    .name = "/",

    .actual_attr = {

        .mode = 0555 | S_IFDIR,

        .nlink = 1,

    },

    .attr = &v9fs_synth_root.actual_attr,

};

static QemuMutex  v9fs_synth_mutex;

static int v9fs_synth_node_count;

/* set to 1 when the synth fs is ready */

static int v9fs_synth_fs;

static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode,

                                        const char *name,

                                        V9fsSynthNodeAttr *attr, int inode)

{

    V9fsSynthNode *node;

    /* Add directory type and remove write bits */

    mode = ((mode & 0777) | S_IFDIR) & ~(S_IWUSR | S_IWGRP | S_IWOTH);

    node = g_malloc0(sizeof(V9fsSynthNode));

    if (attr) {

        /* We are adding .. or . entries */

        node->attr = attr;

        node->attr->nlink++;

    } else {

        node->attr = &node->actual_attr;

        node->attr->inode = inode;

        node->attr->nlink = 1;

        /* We don't allow write to directories */

        node->attr->mode   = mode;

        node->attr->write = NULL;

        node->attr->read  = NULL;

    }

    node->private = node;

    pstrcpy(node->name, sizeof(node->name), name);

    QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling);

    return node;

}

int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode,

                          const char *name, V9fsSynthNode **result)

{

    int ret;

    V9fsSynthNode *node, *tmp;

    if (!v9fs_synth_fs) {

        return EAGAIN;

    }

    if (!name || (strlen(name) >= NAME_MAX)) {

        return EINVAL;

    }

    if (!parent) {

        parent = &v9fs_synth_root;

    }

    qemu_mutex_lock(&v9fs_synth_mutex);

    QLIST_FOREACH(tmp, &parent->child, sibling) {

        if (!strcmp(tmp->name, name)) {

            ret = EEXIST;

            goto err_out;

        }

    }

    /* Add the name */

    node = v9fs_add_dir_node(parent, mode, name, NULL, v9fs_synth_node_count++);

    v9fs_add_dir_node(node, parent->attr->mode, "..",

                      parent->attr, parent->attr->inode);

    v9fs_add_dir_node(node, node->attr->mode, ".",

                      node->attr, node->attr->inode);

    *result = node;

    ret = 0;

err_out:

    qemu_mutex_unlock(&v9fs_synth_mutex);

    return ret;

}

int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode,

                             const char *name, v9fs_synth_read read,

                             v9fs_synth_write write, void *arg)

{

    int ret;

    V9fsSynthNode *node, *tmp;

    if (!v9fs_synth_fs) {

        return EAGAIN;

    }

    if (!name || (strlen(name) >= NAME_MAX)) {

        return EINVAL;

    }

    if (!parent) {

        parent = &v9fs_synth_root;

    }

    qemu_mutex_lock(&v9fs_synth_mutex);

    QLIST_FOREACH(tmp, &parent->child, sibling) {

        if (!strcmp(tmp->name, name)) {

            ret = EEXIST;

            goto err_out;

        }

    }

    /* Add file type and remove write bits */

    mode = ((mode & 0777) | S_IFREG);

    node = g_malloc0(sizeof(V9fsSynthNode));

    node->attr         = &node->actual_attr;

    node->attr->inode  = v9fs_synth_node_count++;

    node->attr->nlink  = 1;

    node->attr->read   = read;

    node->attr->write  = write;

    node->attr->mode   = mode;

    node->private      = arg;

    pstrcpy(node->name, sizeof(node->name), name);

    QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling);

    ret = 0;

err_out:

    qemu_mutex_unlock(&v9fs_synth_mutex);

    return ret;

}

static void v9fs_synth_fill_statbuf(V9fsSynthNode *node, struct stat *stbuf)

{

    stbuf->st_dev = 0;

    stbuf->st_ino = node->attr->inode;

    stbuf->st_mode = node->attr->mode;

    stbuf->st_nlink = node->attr->nlink;

    stbuf->st_uid = 0;

    stbuf->st_gid = 0;

    stbuf->st_rdev = 0;

    stbuf->st_size = 0;

    stbuf->st_blksize = 0;

    stbuf->st_blocks = 0;

    stbuf->st_atime = 0;

    stbuf->st_mtime = 0;

    stbuf->st_ctime = 0;

}

static int v9fs_synth_lstat(FsContext *fs_ctx,

                            V9fsPath *fs_path, struct stat *stbuf)

{

    V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data;

    v9fs_synth_fill_statbuf(node, stbuf);

    return 0;

}

static int v9fs_synth_fstat(FsContext *fs_ctx, int fid_type,

                            V9fsFidOpenState *fs, struct stat *stbuf)

{

    V9fsSynthOpenState *synth_open = fs->private;

    v9fs_synth_fill_statbuf(synth_open->node, stbuf);

    return 0;

}

static int v9fs_synth_opendir(FsContext *ctx,

                             V9fsPath *fs_path, V9fsFidOpenState *fs)

{

    V9fsSynthOpenState *synth_open;

    V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data;

    synth_open = g_malloc(sizeof(*synth_open));

    synth_open->node = node;

    node->open_count++;

    fs->private = synth_open;

    return 0;

}

static int v9fs_synth_closedir(FsContext *ctx, V9fsFidOpenState *fs)

{

    V9fsSynthOpenState *synth_open = fs->private;

    V9fsSynthNode *node = synth_open->node;

    node->open_count--;

    g_free(synth_open);

    fs->private = NULL;

    return 0;

}

static off_t v9fs_synth_telldir(FsContext *ctx, V9fsFidOpenState *fs)

{

    V9fsSynthOpenState *synth_open = fs->private;

    return synth_open->offset;

}

static void v9fs_synth_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)

{

    V9fsSynthOpenState *synth_open = fs->private;

    synth_open->offset = off;

}

static void v9fs_synth_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)

{

    v9fs_synth_seekdir(ctx, fs, 0);

}

static void v9fs_synth_direntry(V9fsSynthNode *node,

                                struct dirent *entry, off_t off)

{

    strcpy(entry->d_name, node->name);

    entry->d_ino = node->attr->inode;

    entry->d_off = off + 1;

}

static int v9fs_synth_get_dentry(V9fsSynthNode *dir, struct dirent *entry,

                                 struct dirent **result, off_t off)

{

    int i = 0;

    V9fsSynthNode *node;

    rcu_read_lock();

    QLIST_FOREACH(node, &dir->child, sibling) {

        /* This is the off child of the directory */

        if (i == off) {

            break;

        }

        i++;

    }

    rcu_read_unlock();

    if (!node) {

        /* end of directory */

        *result = NULL;

        return 0;

    }

    v9fs_synth_direntry(node, entry, off);

    *result = entry;

    return 0;

}

static int v9fs_synth_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,

                                struct dirent *entry, struct dirent **result)

{

    int ret;

    V9fsSynthOpenState *synth_open = fs->private;

    V9fsSynthNode *node = synth_open->node;

    ret = v9fs_synth_get_dentry(node, entry, result, synth_open->offset);

    if (!ret && *result != NULL) {

        synth_open->offset++;

    }

    return ret;

}

static int v9fs_synth_open(FsContext *ctx, V9fsPath *fs_path,

                           int flags, V9fsFidOpenState *fs)

{

    V9fsSynthOpenState *synth_open;

    V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data;

    synth_open = g_malloc(sizeof(*synth_open));

    synth_open->node = node;

    node->open_count++;

    fs->private = synth_open;

    return 0;

}

static int v9fs_synth_open2(FsContext *fs_ctx, V9fsPath *dir_path,

                            const char *name, int flags,

                            FsCred *credp, V9fsFidOpenState *fs)

{

    errno = ENOSYS;

    return -1;

}

static int v9fs_synth_close(FsContext *ctx, V9fsFidOpenState *fs)

{

    V9fsSynthOpenState *synth_open = fs->private;

    V9fsSynthNode *node = synth_open->node;

    node->open_count--;

    g_free(synth_open);

    fs->private = NULL;

    return 0;

}

static ssize_t v9fs_synth_pwritev(FsContext *ctx, V9fsFidOpenState *fs,

                                  const struct iovec *iov,

                                  int iovcnt, off_t offset)

{

    int i, count = 0, wcount;

    V9fsSynthOpenState *synth_open = fs->private;

    V9fsSynthNode *node = synth_open->node;

    if (!node->attr->write) {

        errno = EPERM;

        return -1;

    }

    for (i = 0; i < iovcnt; i++) {

        wcount = node->attr->write(iov[i].iov_base, iov[i].iov_len,

                                   offset, node->private);

        offset += wcount;

        count  += wcount;

        /* If we wrote less than requested. we are done */

        if (wcount < iov[i].iov_len) {

            break;

        }

    }

    return count;

}

static ssize_t v9fs_synth_preadv(FsContext *ctx, V9fsFidOpenState *fs,

                                 const struct iovec *iov,

                                 int iovcnt, off_t offset)

{

    int i, count = 0, rcount;

    V9fsSynthOpenState *synth_open = fs->private;

    V9fsSynthNode *node = synth_open->node;

    if (!node->attr->read) {

        errno = EPERM;

        return -1;

    }

    for (i = 0; i < iovcnt; i++) {

        rcount = node->attr->read(iov[i].iov_base, iov[i].iov_len,

                                  offset, node->private);

        offset += rcount;

        count  += rcount;

        /* If we read less than requested. we are done */

        if (rcount < iov[i].iov_len) {

            break;

        }

    }

    return count;

}

static int v9fs_synth_truncate(FsContext *ctx, V9fsPath *path, off_t offset)

{

    errno = ENOSYS;

    return -1;

}

static int v9fs_synth_chmod(FsContext *fs_ctx, V9fsPath *path, FsCred *credp)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_mknod(FsContext *fs_ctx, V9fsPath *path,

                       const char *buf, FsCred *credp)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_mkdir(FsContext *fs_ctx, V9fsPath *path,

                       const char *buf, FsCred *credp)

{

    errno = EPERM;

    return -1;

}

static ssize_t v9fs_synth_readlink(FsContext *fs_ctx, V9fsPath *path,

                                   char *buf, size_t bufsz)

{

    errno = ENOSYS;

    return -1;

}

static int v9fs_synth_symlink(FsContext *fs_ctx, const char *oldpath,

                              V9fsPath *newpath, const char *buf, FsCred *credp)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_link(FsContext *fs_ctx, V9fsPath *oldpath,

                           V9fsPath *newpath, const char *buf)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_rename(FsContext *ctx, const char *oldpath,

                             const char *newpath)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_chown(FsContext *fs_ctx, V9fsPath *path, FsCred *credp)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_utimensat(FsContext *fs_ctx, V9fsPath *path,

                                const struct timespec *buf)

{

    errno = EPERM;

    return 0;

}

static int v9fs_synth_remove(FsContext *ctx, const char *path)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_fsync(FsContext *ctx, int fid_type,

                            V9fsFidOpenState *fs, int datasync)

{

    errno = ENOSYS;

    return 0;

}

static int v9fs_synth_statfs(FsContext *s, V9fsPath *fs_path,

                             struct statfs *stbuf)

{

    stbuf->f_type = 0xABCD;

    stbuf->f_bsize = 512;

    stbuf->f_blocks = 0;

    stbuf->f_files = v9fs_synth_node_count;

    stbuf->f_namelen = NAME_MAX;

    return 0;

}

static ssize_t v9fs_synth_lgetxattr(FsContext *ctx, V9fsPath *path,

                                    const char *name, void *value, size_t size)

{

    errno = ENOTSUP;

    return -1;

}

static ssize_t v9fs_synth_llistxattr(FsContext *ctx, V9fsPath *path,

                                     void *value, size_t size)

{

    errno = ENOTSUP;

    return -1;

}

static int v9fs_synth_lsetxattr(FsContext *ctx, V9fsPath *path,

                                const char *name, void *value,

                                size_t size, int flags)

{

    errno = ENOTSUP;

    return -1;

}

static int v9fs_synth_lremovexattr(FsContext *ctx,

                                   V9fsPath *path, const char *name)

{

    errno = ENOTSUP;

    return -1;

}

static int v9fs_synth_name_to_path(FsContext *ctx, V9fsPath *dir_path,

                                   const char *name, V9fsPath *target)

{

    V9fsSynthNode *node;

    V9fsSynthNode *dir_node;

    /* "." and ".." are not allowed */

    if (!strcmp(name, ".") || !strcmp(name, "..")) {

        errno = EINVAL;

        return -1;

    }

    if (!dir_path) {

        dir_node = &v9fs_synth_root;

    } else {

        dir_node = *(V9fsSynthNode **)dir_path->data;

    }

    if (!strcmp(name, "/")) {

        node = dir_node;

        goto out;

    }

    /* search for the name in the childern */

    rcu_read_lock();

    QLIST_FOREACH(node, &dir_node->child, sibling) {

        if (!strcmp(node->name, name)) {

            break;

        }

    }

    rcu_read_unlock();

    if (!node) {

        errno = ENOENT;

        return -1;

    }

out:

    /* Copy the node pointer to fid */

    target->data = g_malloc(sizeof(void *));

    memcpy(target->data, &node, sizeof(void *));

    target->size = sizeof(void *);

    return 0;

}

static int v9fs_synth_renameat(FsContext *ctx, V9fsPath *olddir,

                               const char *old_name, V9fsPath *newdir,

                               const char *new_name)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_unlinkat(FsContext *ctx, V9fsPath *dir,

                               const char *name, int flags)

{

    errno = EPERM;

    return -1;

}

static int v9fs_synth_init(FsContext *ctx)

{

    QLIST_INIT(&v9fs_synth_root.child);

    qemu_mutex_init(&v9fs_synth_mutex);

    /* Add "." and ".." entries for root */

    v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode,

                      "..", v9fs_synth_root.attr, v9fs_synth_root.attr->inode);

    v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode,

                      ".", v9fs_synth_root.attr, v9fs_synth_root.attr->inode);

    /* Mark the subsystem is ready for use */

    v9fs_synth_fs = 1;

    return 0;

}

FileOperations synth_ops = {

    .init         = v9fs_synth_init,

    .lstat        = v9fs_synth_lstat,

    .readlink     = v9fs_synth_readlink,

    .close        = v9fs_synth_close,

    .closedir     = v9fs_synth_closedir,

    .open         = v9fs_synth_open,

    .opendir      = v9fs_synth_opendir,

    .rewinddir    = v9fs_synth_rewinddir,

    .telldir      = v9fs_synth_telldir,

    .readdir_r    = v9fs_synth_readdir_r,

    .seekdir      = v9fs_synth_seekdir,

    .preadv       = v9fs_synth_preadv,

    .pwritev      = v9fs_synth_pwritev,

    .chmod        = v9fs_synth_chmod,

    .mknod        = v9fs_synth_mknod,

    .mkdir        = v9fs_synth_mkdir,

    .fstat        = v9fs_synth_fstat,

    .open2        = v9fs_synth_open2,

    .symlink      = v9fs_synth_symlink,

    .link         = v9fs_synth_link,

    .truncate     = v9fs_synth_truncate,

    .rename       = v9fs_synth_rename,

    .chown        = v9fs_synth_chown,

    .utimensat    = v9fs_synth_utimensat,

    .remove       = v9fs_synth_remove,

    .fsync        = v9fs_synth_fsync,

    .statfs       = v9fs_synth_statfs,

    .lgetxattr    = v9fs_synth_lgetxattr,

    .llistxattr   = v9fs_synth_llistxattr,

    .lsetxattr    = v9fs_synth_lsetxattr,

    .lremovexattr = v9fs_synth_lremovexattr,

    .name_to_path = v9fs_synth_name_to_path,

    .renameat     = v9fs_synth_renameat,

    .unlinkat     = v9fs_synth_unlinkat,

};