Add FuseRootReportMaxFree option

Add an option to allow effectively disable file system space checks for
some file managers before copying files to remote drives.

This is a temporary solution. A better solution is to provide each
remote drive with its own mountpoint, so that the xrdp FUSE filesystem
becomes POSIX compliant.

configure.ac

@@ -52,6 +52,7 @@ AM_CONDITIONAL(MACOS, [test "x$macos" = xyes])
 AC_CHECK_SIZEOF([int])
 AC_CHECK_SIZEOF([long])
 AC_CHECK_SIZEOF([void *])
+AC_CHECK_SIZEOF([fsblkcnt_t],,[#include <sys/statvfs.h>])
 
 # runstatedir not available for autoconf <= 2.69
 if test "x$runstatedir" = "x" ; then

docs/man/sesman.ini.5.in

@@ -467,6 +467,22 @@ GNOME 3 versions later than 3.29.92. Do not use this for any other reason.
 This setting will be removed in a later version of xrdp, when GNOME 3 is
 no longer supported.
 
+.TP
+\fBFuseRootReportMaxFree\fR=\fI[false|true]\fR
+The existing FUSE implementation reports free space on remote drives
+in a way which can confuse some file managers if they check for free
+space at the FUSE mountpoint before copying files. KDE Dolphin is
+affected by this, and will report 'no space available' when trying to
+copy to remote drives.
+
+Setting this option will cause the FUSE fileystem to report a
+very large amount of free space for the root of the FUSE mountpoint.
+This will allow Dolphin to copy files to remote drives, but introduces
+a risk that the remote filesystem will run out of space during the copy.
+
+This setting will be removed in a later version of xrdp, when remote drives
+receive unique mountpoints.
+
 .TP
 \fBSoundNumSilentFramesAAC\fR=\fInumber\fR
 Sets the \fInumber\fR of silent frames which are sent to client before close

sesman/chansrv/chansrv_config.c

@@ -44,6 +44,7 @@
 #define DEFAULT_FUSE_DIRECT_IO              0
 #define DEFAULT_FILE_UMASK                  077
 #define DEFAULT_USE_NAUTILUS3_FLIST_FORMAT  0
+#define DEFAULT_FUSE_ROOT_REPORT_MAX_FREE   0
 #define DEFAULT_NUM_SILENT_FRAMES_AAC       4
 #define DEFAULT_NUM_SILENT_FRAMES_MP3       2
 #define DEFAULT_MSEC_DO_NOT_SEND            1000
@@ -252,6 +253,10 @@ read_config_chansrv(log_func_t logmsg,
         {
             cfg->use_nautilus3_flist_format = g_text2bool(value);
         }
+        else if (g_strcasecmp(name, "FuseRootReportMaxFree") == 0)
+        {
+            cfg->fuse_root_report_max_free = g_text2bool(value);
+        }
         else if (g_strcasecmp(name, "SoundNumSilentFramesAAC") == 0)
         {
             cfg->num_silent_frames_aac = strtoul(value, NULL, 0);
@@ -339,6 +344,7 @@ new_config(void)
         cfg->fuse_direct_io = DEFAULT_FUSE_DIRECT_IO;
         cfg->file_umask = DEFAULT_FILE_UMASK;
         cfg->use_nautilus3_flist_format = DEFAULT_USE_NAUTILUS3_FLIST_FORMAT;
+        cfg->fuse_root_report_max_free = DEFAULT_FUSE_ROOT_REPORT_MAX_FREE;
         cfg->num_silent_frames_aac = DEFAULT_NUM_SILENT_FRAMES_AAC;
         cfg->num_silent_frames_mp3 = DEFAULT_NUM_SILENT_FRAMES_MP3;
         cfg->msec_do_not_send = DEFAULT_MSEC_DO_NOT_SEND;
@@ -446,6 +452,8 @@ config_dump(struct config_chansrv *config)
     g_writeln("    FileMask:                  0%o", config->file_umask);
     g_writeln("    Nautilus 3 Flist Format:   %s",
               g_bool2text(config->use_nautilus3_flist_format));
+    g_writeln("    FuseRootReportMaxFree:     %s",
+              g_bool2text(config->fuse_root_report_max_free));
     g_writeln("    LogFilePath            :   %s",
               (config->log_file_path[0]) ? config->log_file_path : "<default>");
 }

sesman/chansrv/chansrv_config.h

@@ -47,6 +47,9 @@ struct config_chansrv
     /** Whether to use nautilus3-compatible file lists for the clipboard */
     int use_nautilus3_flist_format;
 
+    /** Whether to report max free space for the FUSE mountpoint */
+    int fuse_root_report_max_free;
+
     /** Number of silent frames to send before SNDC_CLOSE is sent, setting from sesman.ini */
     unsigned int num_silent_frames_aac;
     unsigned int num_silent_frames_mp3;

sesman/chansrv/chansrv_fuse.c

@@ -2791,6 +2791,22 @@ static void xfuse_cb_statfs(fuse_req_t req, fuse_ino_t ino)
     {
         /* specified file is a local resource */
         struct statvfs vfs_stats = {0};
+        if (g_cfg->fuse_root_report_max_free)
+        {
+            // Report an 95% free max-size filesystem
+            vfs_stats.f_bsize = 0x1000;
+            vfs_stats.f_frsize = vfs_stats.f_bsize;
+#if SIZEOF_FSBLKCNT_T < 8
+            vfs_stats.f_blocks = (fsblkcnt_t) -1;
+#else
+            // Max-size is taken from XFS (8 * 2^60 bytes). Using -1
+            // as a value does not work here.
+            vfs_stats.f_blocks = (fsblkcnt_t)8 * 0x10000 * 0x10000 * 0x10000;
+#endif
+            vfs_stats.f_bfree = vfs_stats.f_blocks - vfs_stats.f_blocks / 20;
+            vfs_stats.f_bavail = vfs_stats.f_bfree;
+            vfs_stats.f_namemax = XFS_MAXFILENAMELEN;
+        }
         fuse_reply_statfs(req, &vfs_stats);
     }
     else

sesman/sesman.ini.in

@@ -200,6 +200,9 @@ FileUmask=077
 ; and up, and you wish to cut-paste files between Nautilus and Windows. Do
 ; not use this setting for GNOME 4, or other file managers
 #UseNautilus3FlistFormat=true
+; Uncomment this line if your file manager erroneously reports
+; 'No free space' when trying to copy any files to remote drives.
+#FuseRootReportMaxFree=true
 ; sound redirection
 ; workaround for Microsoft mstsc.exe to suppress noise.
 ; SoundNumSilentFramesAAC | SoundNumSilentFramesMP3 silent frames are sent before SNDC_CLOSE is sent.