Dropbox FS Fix

fix_dropbox.sh

#!/bin/bash
##############################################################################
#                    Workaround for Dropbox daemon
#                    -----------------------------
# Verified on Dropbox v77.4.131
# Just make it executable (if need, using
#   $ chmod a+x fix_dropbox
# ) and run it.
# Author: Здравко
#   www.dropboxforum.com/t5/user/viewprofilepage/user-id/422790
##############################################################################

# Figure out the target places.
USR_HOME=`realpath ~`
USR_LOCAL="$USR_HOME/.local"
USR_LOCAL_BIN="$USR_LOCAL/bin"
USR_LOCAL_LIB="$USR_LOCAL/lib"
DRB_REPLACEMENT="$USR_LOCAL_BIN/dropbox"
DRB_FIX_LIB="$USR_LOCAL_LIB/libdropbox_ext4.so"
USR_PROFILE="$USR_HOME/.profile"

# Dropbox's components
DBX_SHELL_BASE="/usr/bin"
DBX_SHELL="$DBX_SHELL_BASE/dropbox"
DBX_WEB_SRC_BASE="https://www.dropbox.com/download?dl=packages"
DBX_SCRIPT_ALT="dropbox.py"
DBX_WEB_src="$DBX_WEB_SRC_BASE/$DBX_SCRIPT_ALT"
DBX_SHELL_ALT="$USR_LOCAL_BIN/$DBX_SCRIPT_ALT"

##############################################################################
# Precheck and fix up some prerequisites.

# Ensure target directories are on their place.
if [[ ! -d $USR_LOCAL_BIN ]]
then
  echo "The Directory \"$USR_LOCAL_BIN\" doesn't exist, going to create it."
  mkdir -p $USR_LOCAL_BIN
  if [[ $? -ne 0 || ! -d $USR_LOCAL_BIN ]]
  then
    echo "Directory \"$USR_LOCAL_BIN\" creation fail! Exit."
    exit 1
  fi
fi
if [[ ! -d $USR_LOCAL_LIB ]]
then
  echo "The Directory \"$USR_LOCAL_LIB\" doesn't exist, going to create it."
  mkdir -p $USR_LOCAL_LIB
  if [[ $? -ne 0 || ! -d $USR_LOCAL_LIB ]]
  then
    echo "Directory \"$USR_LOCAL_LIB\" creation fail! Exit."
    exit 1
  fi
fi

# Ensure backup for any existing files.
if [[ -e $DRB_REPLACEMENT ]]
then
  if [[ -f $DRB_REPLACEMENT ]]
  then
    echo "\"$DRB_REPLACEMENT\" already exist, going to back it up."
    mv --backup=t -T $DRB_REPLACEMENT "${DRB_REPLACEMENT}.backup"
    if [[ $? -ne 0 || -e $DRB_REPLACEMENT ]]
    then
      echo "Error backing up \"$DRB_REPLACEMENT\" file! Exit."
      exit 1
    fi
  else
    echo "$DRB_REPLACEMENT is not regular file! Exit."
    exit 1
  fi
fi
if [[ -e $DRB_FIX_LIB ]]
then
  if [[ -f $DRB_FIX_LIB ]]
  then
    echo "\"$DRB_FIX_LIB\" already exist, going to back it up."
    mv --backup=t -T $DRB_FIX_LIB "${DRB_FIX_LIB}.backup"
    if [[ $? -ne 0 || -e $DRB_FIX_LIB ]]
    then
      echo "Error backing up \"$DRB_FIX_LIB\" file! Exit."
      exit 1
    fi
  else
    echo "$DRB_FIX_LIB is not regular file! Exit."
    exit 1
  fi
fi

# Ensure writing permissions.
if [[ ! -w $USR_LOCAL_BIN || ! -x $USR_LOCAL_BIN ]]
then
  chmod u+rwx $USR_LOCAL_BIN
  if [[ $? -ne 0 ]]
  then
    echo "The Directory \"$USR_LOCAL_BIN\" is inaccessible! Exit."
    exit 1
  fi
fi
if [[ ! -w $USR_LOCAL_LIB || ! -x $USR_LOCAL_LIB ]]
then
  chmod u+rwx $USR_LOCAL_LIB
  if [[ $? -ne 0 ]]
  then
    echo "The Directory \"$USR_LOCAL_LIB\" is inaccessible! Exit."
    exit 1
  fi
fi

# Check for preinstalled dropbox shell script.
if [[ ! -e $DBX_SHELL || ! -x $DBX_SHELL ]]
then
  echo "Cannot find pre installed \"$DBX_SHELL\". Will trying alternative."
  DBX_SHELL_BASE="$USR_LOCAL_BIN"
  DBX_SHELL="$DBX_SHELL_ALT"
  # Ensure backup for existing control script.
  if [[ -e $DBX_SHELL_ALT ]]
  then
    if [[ -f $DBX_SHELL_ALT ]]
    then
      echo "\"$DBX_SHELL_ALT\" already exist, going to back it up."
      mv --backup=t -T $DBX_SHELL_ALT "${DBX_SHELL_ALT}.backup"
      if [[ $? -ne 0 || -e $DBX_SHELL_ALT ]]
      then
        echo "Error backing up \"$DBX_SHELL_ALT\" file! Exit."
        exit 1
      fi
    else
      echo "$DBX_SHELL_ALT is not regular file! Exit."
      exit 1
    fi
  fi
fi

##############################################################################
# Generate actual workaround components.

# Fetch Dropbox control script (if need).
if [[ "$DBX_SHELL" == "$DBX_SHELL_ALT" ]]
then
  if ! wget -q -O "$DBX_SHELL_ALT" "$DBX_WEB_SRC"
  then
    echo "Error while download \"$DBX_SHELL_ALT\" from \"$DBX_WEB_SRC\"! Exit."
    exit 1
  fi
  chmod a+x $DBX_SHELL_ALT
  echo "Dropbox control script: \"$DBX_SHELL_ALT\" - ready for use."
fi

# Fixer - source and building.
gcc -shared -fPIC -ldl -xc -o $DRB_FIX_LIB - << EndOfSrc
// Functions replacements
#define _GNU_SOURCE

#include <stdlib.h>
#include <sys/vfs.h>
#include <linux/magic.h>
#include <dlfcn.h>
#include <sys/statvfs.h>
#include <stdarg.h>

static int (*orig_statfs)(const char *path, struct statfs *buf) = NULL;
static int (*orig_statfs64)(const char *path, struct statfs64 *buf) = NULL;
static int (*orig_open64)(const char *pathname, int flags, ...) = NULL;

int statfs(const char *path, struct statfs *buf) {
  if (orig_statfs == NULL) {
    orig_statfs = dlsym(RTLD_NEXT, "statfs");
  }
  register int retval = orig_statfs(path, buf);
  if (retval == 0) {
    buf->f_type = EXT4_SUPER_MAGIC;
  }
  return retval;
}
 
int statfs64(const char *path, struct statfs64 *buf) {
  if (orig_statfs64 == NULL) {
    orig_statfs64 = dlsym(RTLD_NEXT, "statfs64");
  }
  register int retval = orig_statfs64(path, buf);
  if (retval == 0) {
    buf->f_type = EXT4_SUPER_MAGIC;
  }
  return retval;
}

int open64(const char *pathname, int flags, ...) {
  if (orig_open64 == NULL) {
    orig_open64 = dlsym(RTLD_NEXT, "open64");
  }
  register const char *p0 = "/proc/filesystems", *p1 = pathname;
  while(*p0 && *p1 && *p0 == *p1) ++p0, ++p1;
  if (*p0 == '\0' && *p1 == '\0') {
    return -1;
  }
  va_list arg;
  va_start(arg, flags);
  mode_t mode = va_arg (arg, int);
  va_end(arg);
  return orig_open64(pathname, flags, mode);
}
EndOfSrc
if [[ $? -ne 0 ]]
then
  echo "Error building \"$DRB_FIX_LIB\"! Exit."
  exit 2
fi
echo "\"$DRB_FIX_LIB\" - build and ready."

# Wrapper generating.
cat > $DRB_REPLACEMENT << WrapperHead
#!/bin/bash
if [ \$1 == "start" ]
then
  sleep 1
  patchpath=\`realpath \$0\`
  if echo \$(for i in \`ps -C dropbox -o pid\`
            do ls -l /proc/\$i/exe 2>/dev/null | grep -v \$patchpath
            done) | grep dropbox > /dev/null
  then
    timeout=300
    # Make sure there isn't any concurrent start operation in progress.
    $DBX_SHELL running
    while [[ \$? -eq 0 && \$timeout -ne 0 ]]
    do
      sleep 1
      ((--timeout))
      if echo \$(for i in \`ps -C dropbox -o pid\`
                do ls -l /proc/\$i/exe 2>/dev/null | grep -v \$patchpath
                done) | grep dropbox > /dev/null
      then
        $DBX_SHELL running
      fi
    done
    # If there is running application instance, force its stop.
    $DBX_SHELL running
    while [[ \$? -ne 0 && \$timeout -ne 0 ]]
    do
      $DBX_SHELL stop
      sleep 1
      ((--timeout))
      $DBX_SHELL running
    done
    # If something goes wrong...
    if [[ \$timeout -eq 0 ]]
    then
      # ...notify somehow about.
      title="Problem launching Dropbox"
      mainmsg="Possible existing application instance dead"
      submsg="Check that, clear and try start again"
      if which notify-send > /dev/null
      then notify-send --icon=dropbox "\$title" "<b>\$mainmsg\!</b>\n\$submsg."
      elif which zenity > /dev/null
      then zenity --error --title="\$title" --timeout=10 --width=380 \\
        --text="<span size=\"xx-large\"><b>\$mainmsg\!</b>\n\$submsg.</span>" \\
        2> /dev/null
      else echo "  \$title!"
        echo "\$mainmsg."
        echo "\$submsg."
      fi
      exit 1
    fi
  else sleep 100
  fi
fi
WrapperHead
declare -p | grep "declare -x LD_PRELOAD" > /dev/null
if [[ $? -ne 0 ]]
then
  echo "export LD_PRELOAD=$DRB_FIX_LIB" >> $DRB_REPLACEMENT
else
  echo "LD_PRELOAD=$DRB_FIX_LIB:\$LD_PRELOAD" >> $DRB_REPLACEMENT
fi
echo "$DBX_SHELL \$@" >> $DRB_REPLACEMENT
chmod a+x $DRB_REPLACEMENT
echo "\"$DRB_REPLACEMENT\" - generated."

# Environment check and fixup (if need).
echo ""
echo ""
(
IFS=:
for a in $PATH
do
  if [[ "$a" == "$USR_LOCAL_BIN" ]]
  then
    exit 0
  elif [[ "$a" == "$DBX_SHELL_BASE" ]]
  then
    break
  fi
done
exit 1
)
if [[ $? -ne 0 ]]
then
  echo "" >> $USR_PROFILE
  echo "" >> $USR_PROFILE
  echo "# Add $USR_LOCAL_BIN to \$PATH environment variable." >> $USR_PROFILE
  echo "# This addition is dedicated for Dropbox Workaround." >> $USR_PROFILE
  echo "# Remove theses lines when they are no more needed." >> $USR_PROFILE
  echo "PATH=\"$USR_LOCAL_BIN:\$PATH\"" >> $USR_PROFILE
  echo "" >> $USR_PROFILE
  echo "Your Dropbox is almost patched. You have to logout and login"
  echo " (or on Your opinion - restart), so all changes to take effect."
  echo "After Your next account login:"
fi
echo "Your Dropbox is already patched."
if [[ "$DBX_SHELL_BASE" == "$USR_LOCAL_BIN" ]]
then echo "Just type:"
else echo "Just start it from desktop GUI or type:"
fi
echo "\$ dropbox start"
echo "in console (append option -i, when launch for first time)."