(gdb) break *0x972

Have you ever been stuck with password that you web browser knows, but you can't remember it? like that, it's here, but behind the dots ...

The normal way to proceed (in Firefox) in to go to [Preferences|about:preferences] > [Security|about:preferences#security] > Saved passwords, and lookup your password.

The "hacker" way is quicker, but requires a bit of HTML knowledge (but not that much ^^), as well as new web-dev tools, like Firefox's Element Inspector. Right click on your password field, inspect element:

Now you see the source of your web-page. Locate the <input type='password'/> element, and ... delete/edit the field type='password'. That's it ! It's not a password field anymore, so the web-browser doesn't hide it!

Easy peazy :-)

If you're bored with a moving image or text, or an advertisment, you can do the same to get rid of it, that's quite efficient! Just pay attention to what you delete, it's easy to remove the entire page if you delete a top-level element ;-)

• i3 window manager tilling the dual-screen
• Firefox browsing GDB website, certainly looking for its documentation
• Eclipse IDE opened on first investigations of what would become my PhD contribution
• GDB running, trying to capture the behavior of Unix sockets,
• GDB being compiled, as I was also working on its source code
• (I could have a GDB instance debugging the other GDB, but that would have been to much :-)
• Emacs editor opened on my literature review LaTeX document
• Linux kernel configuration panel, as I was building a ARM version to play with ST's Linux kernel debugger
• Unix top command, to make sure that my system is not overloaded by all of the above!

\usepackage{substr}

\newif\ifPaper
% that inside a package, where I can pass "paper" as an option
\DeclareOption{paper}{\global\Papertrue} 

% if substring "paper" is found in the job (file) name, set the flag
\IfSubStringInString{\detokenize{paper}}{\jobname}{\Papertrue}{} 

\newcommand{\link}[2]{
\ifPaper#1\footnote{\url{#2}}\else\href{#2}{#1}\fi
}

ln -s myfile.tex myfile-paper.tex
pdflatex myfile
pdflatex myfile-paper

$ bin/xspecfem3D
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x7FFD9B489BC5
#1  0x4CA9DD in prepare_cleanup_device_ at prepare_mesh_constants_gpu.c:2472
#2  0x40473A in xspecfem3d at specfem3D.F90:473
#3  0x7FFD9930BB44
Segmentation fault

$ gdb bin/xspecfem3D
(gdb) run
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7bd6bc5 in clReleaseMemObject () from /usr/lib/x86_64-linux-gnu/libOpenCL.so.1
(gdb) where
#0  0x00007ffff7bd6bc5 in clReleaseMemObject () from /usr/lib/x86_64-linux-gnu/libOpenCL.so.1
#1  0x00000000004ca9de in prepare_cleanup_device_ () at src/gpu/prepare_mesh_constants_gpu.c:2472
#2  0x000000000040473b in xspecfem3d () at src/specfem3D/specfem3D.F90:473
#3  main () at src/specfem3D/specfem3D.F90:32
#4  0x00007ffff5a58b45 in __libc_start_main () at libc-start.c:287
#5  0x0000000000404780 in _start ()

#ifdef USE_OPENCL
    if (run_opencl) RELEASE_PINNED_BUFFER_OCL (station_seismo_field); // <---- segfault here
#endif
#ifdef USE_CUDA
    if (run_cuda) cudaFreeHost(mp->h_station_seismo_field);
#endif

#define RELEASE_PINNED_BUFFER_OCL(_buffer_) \
     clCheck(clEnqueueUnmapMemObject(mocl.command_queue, mp->h_pinned_##_buffer_, \
                                                           mp->h_##_buffer_, 0, NULL, NULL)); \
     clCheck(clReleaseMemObject (mp->h_pinned_##_buffer_))

(gdb) print mp->h_pinned_station_seismo_field
$1 = (cl_mem) 0x3fd71113a0000000
(gdb) print *mp->h_pinned_station_seismo_field
$2 = <incomplete type>

(gdb) break clEnqueueUnmapMemObject
(gdb) run
Program received signal SIGSEGV, Segmentation fault.

#ifdef USE_OPENCL
   if (run_opencl) RELEASE_PINNED_BUFFER_OCL (station_seismo_field); // <---- segfault here
#endif
#ifdef USE_CUDA
   if (run_cuda) cudaFreeHost(mp->h_station_seismo_field);
#endif

(gdb) print run_opencl
$1 = 0

(gdb) print run_cuda
$2 = 1

if (run_opencl) clCheck(clEnqueueUnmapMemObject(mocl.command_queue, mp->h_pinned_station_seismo_field, 
                                                           mp->h_station_seismo_field, 0, NULL, NULL)); 
     clCheck(clReleaseMemObject (mp->h_pinned_station_seismo_field));

if (run_opencl) {
    RELEASE_PINNED_BUFFER_OCL (station_seismo_field);
}

#define ALLOC_PINNED_BUFFER_OCL(_buffer_, _size_) do { ....} while (0)

(gdb) print mp->h_pinned_station_seismo_field
$1 = (cl_mem) 0x3fd71113a0000000
(gdb) print *mp->h_pinned_station_seismo_field
$2 = <incomplete type>

(mcGDB) opencl info buffer mp->h_pinned_station_seismo_field
No OpenCL buffer at @0x....

(gdb) print run_opencl
$1 = 0

(mcgdb) opencl show activity
No OpenCL activity recorded

• à la TV
• une page sur deux dans les journaux
• à la radio, genre **ça** (la pub Matmut avec Chevalier/Laspales), et c'est l'exemple le plus representatif qu'on puisse trouver simplement ...

                      #0  context_switch ()       at kernel/sched.c:2894
                      #1  schedule ()             at kernel/sched.c:5500
                      #2  do_nanosleep ()         at kernel/hrtimer.c:1494
                      #3  hrtimer_nanosleep ()    at kernel/hrtimer.c:1563
                      #4  sys_nanosleep ()        at kernel/hrtimer.c:1601
                      #5  ret_fast_syscall ()     at arch/arm/kernel/entry-armv.S:744

                      #6  nanosleep ()            at lib/nanosleep.c:51
                      #7  sleep ()                at unix/sysv/linux/sleep.c:138
                      #8  main ()                 at sleep.c:4

main

set backtrace past-main on

set backtrace past-entry on

main

libc

#3  0x00000000004018ed in main () at src/sleep.c:145
#4  0x0000003d49221d65 in __libc_start_main () at libc-start.c:285
#5  0x00000000004019f9 in _start ()

selfoss

define('OCROOT', '$PATH_TO_OWNCLOUD/owncloud/');

function owncloud_get_calendar($username, $cal_id) {
  //it's not necessary to load all apps
  $RUNTIME_NOAPPS = true;
  require_once(OCROOT . '/lib/base.php');
  require_once(OCROOT . '/apps/calendar/appinfo/app.php');
  
  //set userid
  OC_User::setUserId($username);
  
  OCP\User::checkLoggedIn();
  OCP\App::checkAppEnabled('calendar');
  
  $calendar = OC_Calendar_App::getCalendar($cal_id, true, true);
  if(!$calendar) {
    return;
  }
  
  return OC_Calendar_Export::export($cal_id, OC_Calendar_Export::CALENDAR);
}

cal_id

• first, we tell selfoss what information we need to add a new calendar feed: the URL is mandatory, username and password are optional, "days in advance" tells for how many days in advance we want to fetch the events.

public $params = array(
        "url" => array(
            "title"      => "URL",
            "type"       => "text",
            "default"    => "",
             "required"   => true,
            "validation" => array("notempty")
       ),
        "username" => array(
            "title"      => "Username",
            "type"       => "text",
            "default"    => "",
            "required"   => false,
            "validation" => ""
       ),
        "password" => array(
            "title"      => "Password",
            "type"       => "password",
            "default"    => "",
            "required"   => false,
            "validation" => ""
       ),
        "days" => array(
            "title"      => "Days in advance",
            "type"       => "text",
            "default"    => "-1",
            "required"   => false,
            "validation" => "int"
       )
   );

• then we load the calendar, either from Owncloud or directly from its URL. If URL is "owncloud_", we load from owncloud, otherwise, we fetch the URL. Spouts implement the iterator interface, so here we prepare iterator, "rewind" it, and it's ready.

    public function load($params) {
      $link = $params['url'];
      if (strpos($link, "owncloud_") === 0) { // owncloud_<cal_id>
        $calendar_lines = owncloud_get_calendar($params['username'],
                                                substr($link, 1+strpos($link, "_")));

        $ical = new ICal(null, explode("\n", $calendar_lines));
      } else {
        if (!empty($params['password']) && !empty($params['username'])) {
          $auth = $params['username'].":".$params['password']."@";
          $link = str_replace("://", "://$auth", $link);
        }

        $ical = new ICal($link);
      }
      
      $this->items = $ical->events();
      
      $this->days = $params['days'];
      $this->rewind();

      $this->params = $params;
    }

• next this it to select the which events we want to return to Selfoss, in the

  next

  other of the iterator. We count the distance in days, and only print it if it's below the threshold. Obviously, we also discard the past events.

    public function next() {
      if ($this->items == false) {
        return false;
      }
      while (1) {
        $this->position++;

        $event = $this->current_event();
        if (!$event) {
          return false;
        }
        
        $event_date = strtotime($event["DTSTART"]);
        $daydiff = floor(($event_date - time()) / 60 / 60 / 24); // in days
          
        if (isset($event["RRULE"])) { // repeating event
          // explained at the step

        } else { // normal event
          if ($event_date < time()) { // not in the past
            continue;
          }
        }
        if ($this->days !== -1 && $daydiff > $this->days) { // not more than $days of distance
          continue;
        }
        $this->items[$this->position]["DDIST"] = $daydiff;

        return $this->current();
      }
    }

• one kind of events were missing after the first try, it's the repeating events: "every Saturdays, starting the 18th of october". So far I only implemented weekly events, I'll add other kinds whenever I'll need them!

       if (isset($event["RRULE"])) { // repeating event
          if ($event["RRULE"]["FREQ"] === "WEEKLY") {
            if ($event["RRULE"]["INTERVAL"] !== "1") {
              //ignore for now
              continue;
            }
            $DAYS_OF_WEEK = array("SU" => 0, "MO" => 1, "TU" => 2, "WE" => 3, "TH" => 4, "FR" => 5, "SA" => 6);
            $daydiff = $DAYS_OF_WEEK[$event["RRULE"]["BYDAY"]] - date("w");
            if ($daydiff < 0) $daydiff += 7;
            
          } else {
            // ignore for now
            continue;
          }
     }

• the last step was providing Selfoss with the events/items:

    public function getTitle() {
      if ($this->items == false || !$this->valid()) {
        return false;
      }
      
      $event = $this->current_event();
      if (isset($event["RRULE"])) {
        $dispdate = repeating_time($event["RRULE"]) . " " . end_time($event["DTSTART"]);
      } else {
        $dispdate = start_time($event["DTSTART"]);
      }
      $dispdate .= " -> " . end_time($event["DTEND"]);
      
      $text = stripslashes(htmlentities($event["SUMMARY"]));

      return "$dispdate | $text";
    }

    public function getContent() {
        if ($this->items == false || !$this->valid()) {
          return false;
        }
        
        $event = $this->current_event();
            
        $text = stripslashes(htmlentities($event["SUMMARY"]));
        
        $description = "";
        if (isset($event["DESCRIPTION"])) {
          $description = $event["DESCRIPTION"];
        }
        if (isset($event["LOCATION"])) {
          $description .= "\nLocation: ".htmlentities($event["LOCATION"]);
        }

        if ($event["DDIST"] === 0) {
	  $description .= "\nAujourd'hui";
	} else {
          $description .= "\nDans ".$event["DDIST"]. " jour";
          
          if ($disttime !== 1) {
            $description .= "s";
          }
        }

        $description = str_replace("<br>", "\n", htmlentities($description));
        
        return $description;
    }

    public function getId() {
      if ($this->items == false || !$this->valid()) {
        return false;
      }
       
      $id = $this->current_event()["UID"];
      $id .= date("Y-m-d"); // refresh the event every day

      if (strlen($id) > 255) {
        $id = md5($id);
      }
      return $id;
    }

getId

- return $this->backend->get($options);
+ $items = $this->backend->get($options);
+
+ if(!\F3::get('auth')->showHiddenTags()) {
+ foreach($items as $idx => $item) {
+ if (strpos($item['tags'], "@") !== false) {
+ unset($items[$idx]);
+ }
+ }
+ $items = array_values($items);
+ }
+
+ return $items;

• 1) l'ampoule est grillée
• 2) l'interrupteur de la porte de s'active pas
• 3) le frigo n'est pas branché
• 4) il n'y a pas d'électricité dans la maison
• -1) une brique de lait cache l'ampoule
• 0) il y a trop de lumière dans la maison pour distinguer la lumière du frigo

• pour 1) ce n'est pas facile à tester, suivant !
• pour 2) on appuie manuellement sur l’interrupteur, est-ce que ça marche ?
• pour 3) on regarde si la prise est branchée
• pour 4) on allume une lumière dans la maison

1. Maternel, on apprend la vie en communauté
2. Élémentairement, on apprend 1/ le français, 2/ les maths
3. Collège, on apprend l'anglais à la suite du français, en on renforce les maths
4. ==> How you solve x = 5x² + 3x + 10 for x ? heu ... se sé pas !

• parle pas anglais
• sait pas résoudre d'équation
• sourd ! (oui, faut penser à tout :-)