Add support for statvfs() to FUSE

Some desktop environments are now checking for free space before
copying files to a destination.

To support this, the FUSE filesystem needs to convert the statvfs()
system call to the relevent PDUs from [MS-RDPEFS]

(cherry picked from commit 9c93f81)

common/ms-erref.h

@@ -32,6 +32,7 @@ enum NTSTATUS
     STATUS_NO_MORE_FILES         = 0x80000006,
 
     STATUS_UNSUCCESSFUL          = 0xc0000001,
+    STATUS_INFO_LENGTH_MISMATCH  = 0xc0000004,
     STATUS_NO_SUCH_FILE          = 0xc000000f,
     STATUS_ACCESS_DENIED         = 0xc0000022,
     STATUS_OBJECT_NAME_INVALID   = 0xc0000033,

common/ms-fscc.h

@@ -30,7 +30,7 @@
 /*
  * File information classes (section 2.4)
  */
-enum FS_INFORMATION_CLASS
+enum FILE_INFORMATION_CLASS
 {
     FileAllocationInformation    = 19,  /* Set */
     FileBasicInformation         = 4,  /* Query, Set */
@@ -52,6 +52,26 @@ enum FS_INFORMATION_CLASS
 #define FILE_STD_INFORMATION_SIZE 22
 #define FILE_END_OF_FILE_INFORMATION_SIZE 8
 
+/*
+ * File System information classes (section 2.5)
+ */
+enum FILE_SYSTEM_INFORMATION_CLASS
+{
+    FileFsVolumeInformation = 1,
+    FileFsSizeInformation = 3,
+    FileFsDeviceInformation = 4,
+    FileFsAttributeInformation = 5,
+    FileFsFullSizeInformation = 7
+};
+
+/*
+ * Size of structs above without trailing RESERVED fields (MS-RDPEFS
+ * 2.2.3.3.6)
+ */
+#define FILE_FS_SIZE_INFORMATION_SIZE 24
+#define FILE_FS_DEVICE_INFORMATION_SIZE 8
+#define FILE_FS_FULL_SIZE_INFORMATION_SIZE 32
+
 /* Windows file attributes (section 2.6) */
 #define W_FILE_ATTRIBUTE_DIRECTORY      0x00000010
 #define W_FILE_ATTRIBUTE_READONLY       0x00000001

sesman/chansrv/chansrv_fuse.c

@@ -127,6 +127,11 @@ void xfuse_devredir_cb_rename_file(struct state_rename *fip,
 void xfuse_devredir_cb_file_close(struct state_close *fip)
 {}
 
+void xfuse_devredir_cb_statfs(struct state_statfs *fip,
+                              const struct statvfs *fss,
+                              enum NTSTATUS IoStatus)
+{}
+
 int xfuse_path_in_xfuse_fs(const char *path)
 {
     return 0;
@@ -294,6 +299,15 @@ struct state_close
     fuse_ino_t        inum;       /* inum of file to open               */
 };
 
+/*
+ * Record type used to maintain state when running a statfs
+ */
+struct state_statfs
+{
+    fuse_req_t        req;        /* Original FUSE request from statfs  */
+};
+
+
 struct xfuse_handle
 {
     tui32 DeviceId;
@@ -400,6 +414,8 @@ static void xfuse_cb_opendir(fuse_req_t req, fuse_ino_t ino,
 static void xfuse_cb_releasedir(fuse_req_t req, fuse_ino_t ino,
                                 struct fuse_file_info *fi);
 
+static void xfuse_cb_statfs(fuse_req_t req, fuse_ino_t ino);
+
 /* miscellaneous functions */
 static void xfs_inode_to_fuse_entry_param(const XFS_INODE *xinode,
         struct fuse_entry_param *e);
@@ -602,6 +618,7 @@ xfuse_init(void)
     g_xfuse_ops.setattr     = xfuse_cb_setattr;
     g_xfuse_ops.opendir     = xfuse_cb_opendir;
     g_xfuse_ops.releasedir  = xfuse_cb_releasedir;
+    g_xfuse_ops.statfs      = xfuse_cb_statfs;
 
     fuse_opt_add_arg(&args, "xrdp-chansrv");
     fuse_opt_add_arg(&args, g_fuse_root_path);
@@ -1550,6 +1567,26 @@ void xfuse_devredir_cb_file_close(struct state_close *fip)
     free(fip);
 }
 
+void xfuse_devredir_cb_statfs(struct state_statfs *fip,
+                              const struct statvfs *fss,
+                              enum NTSTATUS IoStatus)
+{
+    int status;
+    if (IoStatus != STATUS_SUCCESS)
+    {
+        status =
+            (IoStatus == STATUS_ACCESS_DENIED) ? EACCES :
+            /* default */                        EIO ;
+        fuse_reply_err(fip->req, status);
+    }
+    else
+    {
+        fuse_reply_statfs(fip->req, fss);
+    }
+
+    free(fip);
+}
+
 /*
  * Determine is a file is in the FUSE filesystem
  *
@@ -2660,6 +2697,59 @@ static void xfuse_cb_releasedir(fuse_req_t req, fuse_ino_t ino,
     fuse_reply_err(req, 0);
 }
 
+/*****************************************************************************/
+static void xfuse_cb_statfs(fuse_req_t req, fuse_ino_t ino)
+{
+    XFS_INODE        *xinode;
+
+    LOG_DEVEL(LOG_LEVEL_DEBUG, "entered: ino=%ld", ino);
+
+    if (!(xinode = xfs_get(g_xfs, ino)))
+    {
+        LOG_DEVEL(LOG_LEVEL_ERROR, "inode %ld is not valid", ino);
+        fuse_reply_err(req, ENOENT);
+    }
+    else if (!xinode->is_redirected)
+    {
+        /* specified file is a local resource */
+        struct statvfs vfs_stats = {0};
+        fuse_reply_statfs(req, &vfs_stats);
+    }
+    else
+    {
+        /* specified file resides on redirected share */
+
+        struct state_statfs *fip = g_new0(struct state_statfs, 1);
+        char *full_path = xfs_get_full_path(g_xfs, ino);
+        if (full_path ==NULL || fip == NULL)
+        {
+            LOG_DEVEL(LOG_LEVEL_ERROR, "system out of memory");
+            fuse_reply_err(req, ENOMEM);
+            free(full_path);
+            free(fip);
+        }
+        else
+        {
+            const char      *cptr;
+            fip->req = req;
+
+            /* get devredir to statfs the filesystem for the file
+             *
+             * If this call succeeds, further request processing happens in
+             * xfuse_devredir_cb_statfs()
+             */
+            cptr = filename_on_device(full_path);
+            if (devredir_statfs(fip, xinode->device_id, cptr))
+            {
+                LOG_DEVEL(LOG_LEVEL_ERROR, "failed to send devredir_statfs() cmd");
+                fuse_reply_err(req, EREMOTEIO);
+                free(fip);
+            }
+            free(full_path);
+        }
+    }
+}
+
 /******************************************************************************
  *                           miscellaneous functions
  *****************************************************************************/

sesman/chansrv/chansrv_fuse.h

@@ -72,6 +72,8 @@ struct state_write;
 struct state_remove;
 struct state_rename;
 struct state_close;
+struct statvfs; // OS structure defined in <sys/statvfs.h>
+struct state_statfs;
 
 
 /* functions that are invoked from devredir */
@@ -114,6 +116,10 @@ void xfuse_devredir_cb_rename_file(struct state_rename *fip,
 
 void xfuse_devredir_cb_file_close(struct state_close *fip);
 
+void xfuse_devredir_cb_statfs(struct state_statfs *fip,
+                              const struct statvfs *fss,
+                              enum NTSTATUS IoStatus);
+
 /*
  * Returns true if a filesystem path lies in the FUSE filesystem
  *