Re: [PATCH 09/16] hw/9pfs: Disable unsupported flags and features for Windows

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Monday, October 24, 2022 6:57:52 AM CET Bin Meng wrote:
> From: Guohuai Shi <guohuai.shi@windriver.com>
> 
> Some flags and features are not supported on Windows, like mknod,
> readlink, file mode, etc. Update the codes for Windows.
> 
> Signed-off-by: Guohuai Shi <guohuai.shi@windriver.com>
> Signed-off-by: Bin Meng <bin.meng@windriver.com>
> ---
> 
>  hw/9pfs/9p-util.h |  6 +++-
>  hw/9pfs/9p.c      | 90 ++++++++++++++++++++++++++++++++++++++++++-----
>  2 files changed, 86 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
> index 82b2d0c3e4..3d154e9103 100644
> --- a/hw/9pfs/9p-util.h
> +++ b/hw/9pfs/9p-util.h
> @@ -53,8 +53,10 @@ static inline uint64_t makedev_dotl(uint32_t dev_major, uint32_t dev_minor)
>   */
>  static inline uint64_t host_dev_to_dotl_dev(dev_t dev)
>  {
> -#ifdef CONFIG_LINUX
> +#if defined(CONFIG_LINUX)
>      return dev;
> +#elif defined(CONFIG_WIN32)
> +    return 0;

Really?

>  #else
>      return makedev_dotl(major(dev), minor(dev));
>  #endif
> @@ -260,7 +262,9 @@ static inline struct dirent *qemu_dirent_dup(struct dirent *dent)
>  #if defined CONFIG_DARWIN && defined CONFIG_PTHREAD_FCHDIR_NP
>  int pthread_fchdir_np(int fd) __attribute__((weak_import));
>  #endif
> +#ifndef CONFIG_WIN32
>  int qemu_mknodat(P9_FILE_ID dirfd, const char *filename, mode_t mode,
>                   dev_t dev);
> +#endif
>  
>  #endif
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 6c4af86240..771aab34ac 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -39,6 +39,11 @@
>  #include "qemu/xxhash.h"
>  #include <math.h>
>  
> +#ifdef CONFIG_WIN32
> +#define UTIME_NOW   ((1l << 30) - 1l)
> +#define UTIME_OMIT  ((1l << 30) - 2l)
> +#endif
> +
>  int open_fd_hw;
>  int total_open_fd;
>  static int open_fd_rc;
> @@ -132,13 +137,17 @@ static int dotl_to_open_flags(int flags)
>      DotlOpenflagMap dotl_oflag_map[] = {
>          { P9_DOTL_CREATE, O_CREAT },
>          { P9_DOTL_EXCL, O_EXCL },
> +#ifndef CONFIG_WIN32
>          { P9_DOTL_NOCTTY , O_NOCTTY },
> +#endif
>          { P9_DOTL_TRUNC, O_TRUNC },
>          { P9_DOTL_APPEND, O_APPEND },
> +#ifndef CONFIG_WIN32
>          { P9_DOTL_NONBLOCK, O_NONBLOCK } ,
>          { P9_DOTL_DSYNC, O_DSYNC },
>          { P9_DOTL_FASYNC, FASYNC },
> -#ifndef CONFIG_DARWIN
> +#endif
> +#ifdef CONFIG_LINUX

Better

   #if !defined(CONFIG_DARWIN) && !defined(CONFIG_WIN32)

Otherwise it might automatically opt-out other future platforms
unintentionally.

>          { P9_DOTL_NOATIME, O_NOATIME },
>          /*
>           *  On Darwin, we could map to F_NOCACHE, which is
> @@ -151,8 +160,10 @@ static int dotl_to_open_flags(int flags)
>  #endif
>          { P9_DOTL_LARGEFILE, O_LARGEFILE },
>          { P9_DOTL_DIRECTORY, O_DIRECTORY },
> +#ifndef CONFIG_WIN32
>          { P9_DOTL_NOFOLLOW, O_NOFOLLOW },
>          { P9_DOTL_SYNC, O_SYNC },
> +#endif
>      };
>  
>      for (i = 0; i < ARRAY_SIZE(dotl_oflag_map); i++) {
> @@ -179,8 +190,11 @@ static int get_dotl_openflags(V9fsState *s, int oflags)
>       * Filter the client open flags
>       */
>      flags = dotl_to_open_flags(oflags);
> -    flags &= ~(O_NOCTTY | O_ASYNC | O_CREAT);
> -#ifndef CONFIG_DARWIN
> +    flags &= ~(O_CREAT);
> +#ifndef CONFIG_WIN32
> +    flags &= ~(O_NOCTTY | O_ASYNC);
> +#endif
> +#ifdef CONFIG_LINUX

Same as above: better explicitly opt-out than the other way around.

>      /*
>       * Ignore direct disk access hint until the server supports it.
>       */
> @@ -986,9 +1000,11 @@ static int stat_to_qid(V9fsPDU *pdu, const struct stat *stbuf, V9fsQID *qidp)
>      if (S_ISDIR(stbuf->st_mode)) {
>          qidp->type |= P9_QID_TYPE_DIR;
>      }
> +#ifndef CONFIG_WIN32
>      if (S_ISLNK(stbuf->st_mode)) {
>          qidp->type |= P9_QID_TYPE_SYMLINK;
>      }
> +#endif
>  
>      return 0;
>  }
> @@ -1097,6 +1113,7 @@ static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)
>          ret |= S_IFDIR;
>      }
>  
> +#ifndef CONFIG_WIN32
>      if (mode & P9_STAT_MODE_SYMLINK) {
>          ret |= S_IFLNK;
>      }
> @@ -1106,6 +1123,7 @@ static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)
>      if (mode & P9_STAT_MODE_NAMED_PIPE) {
>          ret |= S_IFIFO;
>      }
> +#endif
>      if (mode & P9_STAT_MODE_DEVICE) {
>          if (extension->size && extension->data[0] == 'c') {
>              ret |= S_IFCHR;
> @@ -1118,6 +1136,7 @@ static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)
>          ret |= S_IFREG;
>      }
>  
> +#ifndef CONFIG_WIN32
>      if (mode & P9_STAT_MODE_SETUID) {
>          ret |= S_ISUID;
>      }
> @@ -1127,6 +1146,7 @@ static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)
>      if (mode & P9_STAT_MODE_SETVTX) {
>          ret |= S_ISVTX;
>      }
> +#endif
>  
>      return ret;
>  }
> @@ -1182,6 +1202,7 @@ static uint32_t stat_to_v9mode(const struct stat *stbuf)
>          mode |= P9_STAT_MODE_DIR;
>      }
>  
> +#ifndef CONFIG_WIN32
>      if (S_ISLNK(stbuf->st_mode)) {
>          mode |= P9_STAT_MODE_SYMLINK;
>      }
> @@ -1193,11 +1214,13 @@ static uint32_t stat_to_v9mode(const struct stat *stbuf)
>      if (S_ISFIFO(stbuf->st_mode)) {
>          mode |= P9_STAT_MODE_NAMED_PIPE;
>      }
> +#endif
>  
>      if (S_ISBLK(stbuf->st_mode) || S_ISCHR(stbuf->st_mode)) {
>          mode |= P9_STAT_MODE_DEVICE;
>      }
>  
> +#ifndef CONFIG_WIN32
>      if (stbuf->st_mode & S_ISUID) {
>          mode |= P9_STAT_MODE_SETUID;
>      }
> @@ -1209,6 +1232,7 @@ static uint32_t stat_to_v9mode(const struct stat *stbuf)
>      if (stbuf->st_mode & S_ISVTX) {
>          mode |= P9_STAT_MODE_SETVTX;
>      }
> +#endif
>  
>      return mode;
>  }
> @@ -1247,9 +1271,17 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *path,
>              return err;
>          }
>      } else if (v9stat->mode & P9_STAT_MODE_DEVICE) {
> +        unsigned maj, min;
> +
> +#ifndef CONFIG_WIN32
> +        maj = major(stbuf->st_rdev);
> +        min = minor(stbuf->st_rdev);
> +#else
> +        maj = min = 0;
> +#endif

Really?

>          v9fs_string_sprintf(&v9stat->extension, "%c %u %u",
>                  S_ISCHR(stbuf->st_mode) ? 'c' : 'b',
> -                major(stbuf->st_rdev), minor(stbuf->st_rdev));
> +                maj, min);
>      } else if (S_ISDIR(stbuf->st_mode) || S_ISREG(stbuf->st_mode)) {
>          v9fs_string_sprintf(&v9stat->extension, "%s %lu",
>                  "HARDLINKCOUNT", (unsigned long)stbuf->st_nlink);
> @@ -1317,7 +1349,14 @@ static int32_t blksize_to_iounit(const V9fsPDU *pdu, int32_t blksize)
>  
>  static int32_t stat_to_iounit(const V9fsPDU *pdu, const struct stat *stbuf)
>  {
> -    return blksize_to_iounit(pdu, stbuf->st_blksize);
> +    int32_t blksize;
> +
> +#ifndef CONFIG_WIN32
> +    blksize = stbuf->st_blksize);
> +#else
> +    blksize = 0;
> +#endif

Really?

> +    return blksize_to_iounit(pdu, blksize);
>  }
>  
>  static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf,
> @@ -1332,7 +1371,11 @@ static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf,
>      v9lstat->st_rdev = host_dev_to_dotl_dev(stbuf->st_rdev);
>      v9lstat->st_size = stbuf->st_size;
>      v9lstat->st_blksize = stat_to_iounit(pdu, stbuf);
> +#ifndef CONFIG_WIN32
>      v9lstat->st_blocks = stbuf->st_blocks;
> +#else
> +    v9lstat->st_blocks = 0;
> +#endif

Really?

>      v9lstat->st_atime_sec = stbuf->st_atime;
>      v9lstat->st_mtime_sec = stbuf->st_mtime;
>      v9lstat->st_ctime_sec = stbuf->st_ctime;
> @@ -1340,7 +1383,8 @@ static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf,
>      v9lstat->st_atime_nsec = stbuf->st_atimespec.tv_nsec;
>      v9lstat->st_mtime_nsec = stbuf->st_mtimespec.tv_nsec;
>      v9lstat->st_ctime_nsec = stbuf->st_ctimespec.tv_nsec;
> -#else
> +#endif
> +#ifdef CONFIG_LINUX
>      v9lstat->st_atime_nsec = stbuf->st_atim.tv_nsec;
>      v9lstat->st_mtime_nsec = stbuf->st_mtim.tv_nsec;
>      v9lstat->st_ctime_nsec = stbuf->st_ctim.tv_nsec;
> @@ -2471,6 +2515,7 @@ static int coroutine_fn v9fs_do_readdir(V9fsPDU *pdu, V9fsFidState *fidp,
>      struct dirent *dent;
>      struct stat *st;
>      struct V9fsDirEnt *entries = NULL;
> +    unsigned char d_type = 0;
>  
>      /*
>       * inode remapping requires the device id, which in turn might be
> @@ -2540,10 +2585,13 @@ static int coroutine_fn v9fs_do_readdir(V9fsPDU *pdu, V9fsFidState *fidp,
>          v9fs_string_init(&name);
>          v9fs_string_sprintf(&name, "%s", dent->d_name);
>  
> +#ifndef CONFIG_WIN32
> +        d_type = dent->d_type;
> +#endif
>          /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */
>          len = pdu_marshal(pdu, 11 + count, "Qqbs",
>                            &qid, off,
> -                          dent->d_type, &name);
> +                          d_type, &name);

Are you saying that d_type is not initialized with zero already?

>          v9fs_string_free(&name);
>  
> @@ -2873,8 +2921,12 @@ static void coroutine_fn v9fs_create(void *opaque)
>          }
>  
>          nmode |= perm & 0777;
> +#ifndef CONFIG_WIN32
>          err = v9fs_co_mknod(pdu, fidp, &name, fidp->uid, -1,
>                              makedev(major, minor), nmode, &stbuf);
> +#else
> +        err = -ENOTSUP;
> +#endif
>          if (err < 0) {
>              goto out;
>          }
> @@ -2899,8 +2951,12 @@ static void coroutine_fn v9fs_create(void *opaque)
>          v9fs_path_copy(&fidp->path, &path);
>          v9fs_path_unlock(s);
>      } else if (perm & P9_STAT_MODE_SOCKET) {
> +#ifndef CONFIG_WIN32
>          err = v9fs_co_mknod(pdu, fidp, &name, fidp->uid, -1,
>                              0, S_IFSOCK | (perm & 0777), &stbuf);
> +#else
> +        err = -ENOTSUP;
> +#endif

As with previous patches, I would consider making the user aware to use
mapped(-xattr) with something like error_report_once().

>          if (err < 0) {
>              goto out;
>          }
> @@ -3634,7 +3690,7 @@ out_nofid:
>  
>  static void coroutine_fn v9fs_mknod(void *opaque)
>  {
> -
> +#ifndef CONFIG_WIN32
>      int mode;
>      gid_t gid;
>      int32_t fid;
> @@ -3691,6 +3747,10 @@ out:
>  out_nofid:
>      pdu_complete(pdu, err);
>      v9fs_string_free(&name);
> +#else
> +    V9fsPDU *pdu = opaque;
> +    pdu_complete(pdu, -1);
> +#endif
>  }
>  
>  /*
> @@ -3963,7 +4023,7 @@ out_nofid:
>  #if defined(CONFIG_LINUX)
>  /* Currently, only Linux has XATTR_SIZE_MAX */
>  #define P9_XATTR_SIZE_MAX XATTR_SIZE_MAX
> -#elif defined(CONFIG_DARWIN)
> +#elif defined(CONFIG_DARWIN) || defined(CONFIG_WIN32)
>  /*
>   * Darwin doesn't seem to define a maximum xattr size in its user
>   * space header, so manually configure it across platforms as 64k.
> @@ -3980,6 +4040,7 @@ out_nofid:
>  
>  static void coroutine_fn v9fs_xattrcreate(void *opaque)
>  {
> +#ifndef CONFIG_WIN32
>      int flags, rflags = 0;
>      int32_t fid;
>      uint64_t size;
> @@ -4041,10 +4102,15 @@ out_put_fid:
>  out_nofid:
>      pdu_complete(pdu, err);
>      v9fs_string_free(&name);
> +#else
> +    V9fsPDU *pdu = opaque;
> +    pdu_complete(pdu, -1);
> +#endif
>  }
>  
>  static void coroutine_fn v9fs_readlink(void *opaque)
>  {
> +#ifndef CONFIG_WIN32
>      V9fsPDU *pdu = opaque;
>      size_t offset = 7;
>      V9fsString target;
> @@ -4080,6 +4146,10 @@ out:
>      put_fid(pdu, fidp);
>  out_nofid:
>      pdu_complete(pdu, err);
> +#else
> +    V9fsPDU *pdu = opaque;
> +    pdu_complete(pdu, -1);
> +#endif

Unnecessary double declaration of pdu.

>  }
>  
>  static CoroutineEntry *pdu_co_handlers[] = {
> @@ -4341,6 +4411,7 @@ void v9fs_reset(V9fsState *s)
>  
>  static void __attribute__((__constructor__)) v9fs_set_fd_limit(void)
>  {
> +#ifndef CONFIG_WIN32
>      struct rlimit rlim;
>      if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
>          error_report("Failed to get the resource limit");
> @@ -4348,4 +4419,5 @@ static void __attribute__((__constructor__)) v9fs_set_fd_limit(void)
>      }
>      open_fd_hw = rlim.rlim_cur - MIN(400, rlim.rlim_cur / 3);
>      open_fd_rc = rlim.rlim_cur / 2;
> +#endif

Really?

>  }
>