Archipelago » qemu

/*

 * Virtio 9p Posix callback

 *

 * Copyright IBM, Corp. 2010

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.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 "virtio.h"

#include "virtio-9p.h"

#include <arpa/inet.h>

#include <pwd.h>

#include <grp.h>

#include <sys/socket.h>

#include <sys/un.h>

#include <attr/xattr.h>

static const char *rpath(FsContext *ctx, const char *path)

{

    /* FIXME: so wrong... */

    static char buffer[4096];

    snprintf(buffer, sizeof(buffer), "%s/%s", ctx->fs_root, path);

    return buffer;

}

static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf)

{

    int err;

    err =  lstat(rpath(fs_ctx, path), stbuf);

    if (err) {

        return err;

    }

    if (fs_ctx->fs_sm == SM_MAPPED) {

        /* Actual credentials are part of extended attrs */

        uid_t tmp_uid;

        gid_t tmp_gid;

        mode_t tmp_mode;

        dev_t tmp_dev;

        if (getxattr(rpath(fs_ctx, path), "user.virtfs.uid", &tmp_uid,

                    sizeof(uid_t)) > 0) {

            stbuf->st_uid = tmp_uid;

        }

        if (getxattr(rpath(fs_ctx, path), "user.virtfs.gid", &tmp_gid,

                    sizeof(gid_t)) > 0) {

            stbuf->st_gid = tmp_gid;

        }

        if (getxattr(rpath(fs_ctx, path), "user.virtfs.mode", &tmp_mode,

                    sizeof(mode_t)) > 0) {

            stbuf->st_mode = tmp_mode;

        }

        if (getxattr(rpath(fs_ctx, path), "user.virtfs.rdev", &tmp_dev,

                        sizeof(dev_t)) > 0) {

                stbuf->st_rdev = tmp_dev;

        }

    }

    return err;

}

static int local_set_xattr(const char *path, FsCred *credp)

{

    int err;

    if (credp->fc_uid != -1) {

        err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),

                0);

        if (err) {

            return err;

        }

    }

    if (credp->fc_gid != -1) {

        err = setxattr(path, "user.virtfs.gid", &credp->fc_gid, sizeof(gid_t),

                0);

        if (err) {

            return err;

        }

    }

    if (credp->fc_mode != -1) {

        err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,

                sizeof(mode_t), 0);

        if (err) {

            return err;

        }

    }

    if (credp->fc_rdev != -1) {

        err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,

                sizeof(dev_t), 0);

        if (err) {

            return err;

        }

    }

    return 0;

}

static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,

        FsCred *credp)

{

    if (chmod(rpath(fs_ctx, path), credp->fc_mode & 07777) < 0) {

        return -1;

    }

    if (lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid) < 0) {

        /*

         * If we fail to change ownership and if we are

         * using security model none. Ignore the error

         */

        if (fs_ctx->fs_sm != SM_NONE) {

            return -1;

        }

    }

    return 0;

}

static ssize_t local_readlink(FsContext *fs_ctx, const char *path,

        char *buf, size_t bufsz)

{

    ssize_t tsize = -1;

    if (fs_ctx->fs_sm == SM_MAPPED) {

        int fd;

        fd = open(rpath(fs_ctx, path), O_RDONLY);

        if (fd == -1) {

            return -1;

        }

        do {

            tsize = read(fd, (void *)buf, bufsz);

        } while (tsize == -1 && errno == EINTR);

        close(fd);

        return tsize;

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        tsize = readlink(rpath(fs_ctx, path), buf, bufsz);

    }

    return tsize;

}

static int local_close(FsContext *ctx, int fd)

{

    return close(fd);

}

static int local_closedir(FsContext *ctx, DIR *dir)

{

    return closedir(dir);

}

static int local_open(FsContext *ctx, const char *path, int flags)

{

    return open(rpath(ctx, path), flags);

}

static DIR *local_opendir(FsContext *ctx, const char *path)

{

    return opendir(rpath(ctx, path));

}

static void local_rewinddir(FsContext *ctx, DIR *dir)

{

    return rewinddir(dir);

}

static off_t local_telldir(FsContext *ctx, DIR *dir)

{

    return telldir(dir);

}

static struct dirent *local_readdir(FsContext *ctx, DIR *dir)

{

    return readdir(dir);

}

static void local_seekdir(FsContext *ctx, DIR *dir, off_t off)

{

    return seekdir(dir, off);

}

static ssize_t local_readv(FsContext *ctx, int fd, const struct iovec *iov,

                            int iovcnt)

{

    return readv(fd, iov, iovcnt);

}

static off_t local_lseek(FsContext *ctx, int fd, off_t offset, int whence)

{

    return lseek(fd, offset, whence);

}

static ssize_t local_writev(FsContext *ctx, int fd, const struct iovec *iov,

                            int iovcnt)

{

    return writev(fd, iov, iovcnt);

}

static int local_chmod(FsContext *fs_ctx, const char *path, FsCred *credp)

{

    if (fs_ctx->fs_sm == SM_MAPPED) {

        return local_set_xattr(rpath(fs_ctx, path), credp);

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        return chmod(rpath(fs_ctx, path), credp->fc_mode);

    }

    return -1;

}

static int local_mknod(FsContext *fs_ctx, const char *path, FsCred *credp)

{

    int err = -1;

    int serrno = 0;

    /* Determine the security model */

    if (fs_ctx->fs_sm == SM_MAPPED) {

        err = mknod(rpath(fs_ctx, path), SM_LOCAL_MODE_BITS|S_IFREG, 0);

        if (err == -1) {

            return err;

        }

        local_set_xattr(rpath(fs_ctx, path), credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        err = mknod(rpath(fs_ctx, path), credp->fc_mode, credp->fc_rdev);

        if (err == -1) {

            return err;

        }

        err = local_post_create_passthrough(fs_ctx, path, credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    }

    return err;

err_end:

    remove(rpath(fs_ctx, path));

    errno = serrno;

    return err;

}

static int local_mkdir(FsContext *fs_ctx, const char *path, FsCred *credp)

{

    int err = -1;

    int serrno = 0;

    /* Determine the security model */

    if (fs_ctx->fs_sm == SM_MAPPED) {

        err = mkdir(rpath(fs_ctx, path), SM_LOCAL_DIR_MODE_BITS);

        if (err == -1) {

            return err;

        }

        credp->fc_mode = credp->fc_mode|S_IFDIR;

        err = local_set_xattr(rpath(fs_ctx, path), credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        err = mkdir(rpath(fs_ctx, path), credp->fc_mode);

        if (err == -1) {

            return err;

        }

        err = local_post_create_passthrough(fs_ctx, path, credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    }

    return err;

err_end:

    remove(rpath(fs_ctx, path));

    errno = serrno;

    return err;

}

static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)

{

    int err;

    err = fstat(fd, stbuf);

    if (err) {

        return err;

    }

    if (fs_ctx->fs_sm == SM_MAPPED) {

        /* Actual credentials are part of extended attrs */

        uid_t tmp_uid;

        gid_t tmp_gid;

        mode_t tmp_mode;

        dev_t tmp_dev;

        if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {

            stbuf->st_uid = tmp_uid;

        }

        if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {

            stbuf->st_gid = tmp_gid;

        }

        if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {

            stbuf->st_mode = tmp_mode;

        }

        if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {

                stbuf->st_rdev = tmp_dev;

        }

    }

    return err;

}

static int local_open2(FsContext *fs_ctx, const char *path, int flags,

        FsCred *credp)

{

    int fd = -1;

    int err = -1;

    int serrno = 0;

    /* Determine the security model */

    if (fs_ctx->fs_sm == SM_MAPPED) {

        fd = open(rpath(fs_ctx, path), flags, SM_LOCAL_MODE_BITS);

        if (fd == -1) {

            return fd;

        }

        credp->fc_mode = credp->fc_mode|S_IFREG;

        /* Set cleint credentials in xattr */

        err = local_set_xattr(rpath(fs_ctx, path), credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        fd = open(rpath(fs_ctx, path), flags, credp->fc_mode);

        if (fd == -1) {

            return fd;

        }

        err = local_post_create_passthrough(fs_ctx, path, credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    }

    return fd;

err_end:

    close(fd);

    remove(rpath(fs_ctx, path));

    errno = serrno;

    return err;

}

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

        const char *newpath, FsCred *credp)

{

    int err = -1;

    int serrno = 0;

    /* Determine the security model */

    if (fs_ctx->fs_sm == SM_MAPPED) {

        int fd;

        ssize_t oldpath_size, write_size;

        fd = open(rpath(fs_ctx, newpath), O_CREAT|O_EXCL|O_RDWR,

                SM_LOCAL_MODE_BITS);

        if (fd == -1) {

            return fd;

        }

        /* Write the oldpath (target) to the file. */

        oldpath_size = strlen(oldpath) + 1;

        do {

            write_size = write(fd, (void *)oldpath, oldpath_size);

        } while (write_size == -1 && errno == EINTR);

        if (write_size != oldpath_size) {

            serrno = errno;

            close(fd);

            err = -1;

            goto err_end;

        }

        close(fd);

        /* Set cleint credentials in symlink's xattr */

        credp->fc_mode = credp->fc_mode|S_IFLNK;

        err = local_set_xattr(rpath(fs_ctx, newpath), credp);

        if (err == -1) {

            serrno = errno;

            goto err_end;

        }

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        err = symlink(oldpath, rpath(fs_ctx, newpath));

        if (err) {

            return err;

        }

        err = lchown(rpath(fs_ctx, newpath), credp->fc_uid, credp->fc_gid);

        if (err == -1) {

            /*

             * If we fail to change ownership and if we are

             * using security model none. Ignore the error

             */

            if (fs_ctx->fs_sm != SM_NONE) {

                serrno = errno;

                goto err_end;

            } else

                err = 0;

        }

    }

    return err;

err_end:

    remove(rpath(fs_ctx, newpath));

    errno = serrno;

    return err;

}

static int local_link(FsContext *ctx, const char *oldpath, const char *newpath)

{

    char *tmp = qemu_strdup(rpath(ctx, oldpath));

    int err, serrno = 0;

    if (tmp == NULL) {

        return -ENOMEM;

    }

    err = link(tmp, rpath(ctx, newpath));

    if (err == -1) {

        serrno = errno;

    }

    qemu_free(tmp);

    if (err == -1) {

        errno = serrno;

    }

    return err;

}

static int local_truncate(FsContext *ctx, const char *path, off_t size)

{

    return truncate(rpath(ctx, path), size);

}

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

                        const char *newpath)

{

    char *tmp;

    int err;

    tmp = qemu_strdup(rpath(ctx, oldpath));

    err = rename(tmp, rpath(ctx, newpath));

    if (err == -1) {

        int serrno = errno;

        qemu_free(tmp);

        errno = serrno;

    } else {

        qemu_free(tmp);

    }

    return err;

}

static int local_chown(FsContext *fs_ctx, const char *path, FsCred *credp)

{

    if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||

            (fs_ctx->fs_sm == SM_PASSTHROUGH)) {

        return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);

    } else if (fs_ctx->fs_sm == SM_MAPPED) {

        return local_set_xattr(rpath(fs_ctx, path), credp);

    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||

               (fs_ctx->fs_sm == SM_NONE)) {

        return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);

    }

    return -1;

}

static int local_utimensat(FsContext *s, const char *path,

                       const struct timespec *buf)

{

    return utimensat(AT_FDCWD, rpath(s, path), buf, AT_SYMLINK_NOFOLLOW);

}

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

{

    return remove(rpath(ctx, path));

}

static int local_fsync(FsContext *ctx, int fd)

{

    return fsync(fd);

}

static int local_statfs(FsContext *s, const char *path, struct statfs *stbuf)

{

   return statfs(rpath(s, path), stbuf);

}

static ssize_t local_lgetxattr(FsContext *ctx, const char *path,

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

{

    if ((ctx->fs_sm == SM_MAPPED) &&

        (strncmp(name, "user.virtfs.", 12) == 0)) {

        /*

         * Don't allow fetch of user.virtfs namesapce

         * in case of mapped security

         */

        errno = ENOATTR;

        return -1;

    }

    return lgetxattr(rpath(ctx, path), name, value, size);

}

static ssize_t local_llistxattr(FsContext *ctx, const char *path,

                                void *value, size_t size)

{

    ssize_t retval;

    ssize_t actual_len = 0;

    char *orig_value, *orig_value_start;

    char *temp_value, *temp_value_start;

    ssize_t xattr_len, parsed_len = 0, attr_len;

    if (ctx->fs_sm != SM_MAPPED) {

        return llistxattr(rpath(ctx, path), value, size);

    }

    /* Get the actual len */

    xattr_len = llistxattr(rpath(ctx, path), value, 0);

    /* Now fetch the xattr and find the actual size */

    orig_value = qemu_malloc(xattr_len);

    xattr_len = llistxattr(rpath(ctx, path), orig_value, xattr_len);

    /*

     * For mapped security model drop user.virtfs namespace

     * from the list

     */

    temp_value = qemu_mallocz(xattr_len);

    temp_value_start = temp_value;

    orig_value_start = orig_value;

    while (xattr_len > parsed_len) {

        attr_len = strlen(orig_value) + 1;

        if (strncmp(orig_value, "user.virtfs.", 12) != 0) {

            /* Copy this entry */

            strcat(temp_value, orig_value);

            temp_value  += attr_len;

            actual_len += attr_len;

        }

        parsed_len += attr_len;

        orig_value += attr_len;

    }

    if (!size) {

        retval = actual_len;

        goto out;

    } else if (size >= actual_len) {

        /* now copy the parsed attribute list back */

        memset(value, 0, size);

        memcpy(value, temp_value_start, actual_len);

        retval = actual_len;

        goto out;

    }

    errno = ERANGE;

    retval = -1;

out:

    qemu_free(orig_value_start);

    qemu_free(temp_value_start);

    return retval;

}

static int local_lsetxattr(FsContext *ctx, const char *path, const char *name,

                           void *value, size_t size, int flags)

{

    if ((ctx->fs_sm == SM_MAPPED) &&

        (strncmp(name, "user.virtfs.", 12) == 0)) {

        /*

         * Don't allow fetch of user.virtfs namesapce

         * in case of mapped security

         */

        errno = EACCES;

        return -1;

    }

    return lsetxattr(rpath(ctx, path), name, value, size, flags);

}

static int local_lremovexattr(FsContext *ctx,

                              const char *path, const char *name)

{

    if ((ctx->fs_sm == SM_MAPPED) &&

        (strncmp(name, "user.virtfs.", 12) == 0)) {

        /*

         * Don't allow fetch of user.virtfs namesapce

         * in case of mapped security

         */

        errno = EACCES;

        return -1;

    }

    return lremovexattr(rpath(ctx, path), name);

}

FileOperations local_ops = {

    .lstat = local_lstat,

    .readlink = local_readlink,

    .close = local_close,

    .closedir = local_closedir,

    .open = local_open,

    .opendir = local_opendir,

    .rewinddir = local_rewinddir,

    .telldir = local_telldir,

    .readdir = local_readdir,

    .seekdir = local_seekdir,

    .readv = local_readv,

    .lseek = local_lseek,

    .writev = local_writev,

    .chmod = local_chmod,

    .mknod = local_mknod,

    .mkdir = local_mkdir,

    .fstat = local_fstat,

    .open2 = local_open2,

    .symlink = local_symlink,

    .link = local_link,

    .truncate = local_truncate,

    .rename = local_rename,

    .chown = local_chown,

    .utimensat = local_utimensat,

    .remove = local_remove,

    .fsync = local_fsync,

    .statfs = local_statfs,

    .lgetxattr = local_lgetxattr,

    .llistxattr = local_llistxattr,

    .lsetxattr = local_lsetxattr,

    .lremovexattr = local_lremovexattr,

};