The Tor Browser: tools/footprint/thrashview.cpp@97036ab72558 (annotated)

tools/footprint/thrashview.cpp@97036ab72558 (annotated)

tools/footprint/thrashview.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * ``thrashview'' is a program that reads a binary stream of addresses
  * from stdin and displays the pattern graphically in a window.
  */
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/time.h>
 #include <unistd.h>
 #include <X11/Xlib.h>
 #include <fstream>
 #include <getopt.h>
 #define GET_DISPLAY_FD(display_) ConnectionNumber(display_)
 static bool opt_working_set = false;
 static bool opt_fixed = false;
 static Display *display;
 static Window window;
 static GC gc;
 static XColor colors[256];
 const unsigned int cellsize = 4;
 static unsigned int width = 64 * cellsize;
 static unsigned int height = 64 * cellsize;
 #define PAGESIZE 4096
 #define MAXPAGES 4096  // should hold 16MB worth of code
 static unsigned int minpage = static_cast<unsigned int>(-1);
 static unsigned int maxpage = 0;
 static unsigned char pages[MAXPAGES];
 /**
  * Create a simple window and the X objects we'll need to talk with it.
  */
 static int
 init()
 {
     display = XOpenDisplay(0);
     if (! display)
         return 0;
     window =
         XCreateSimpleWindow(display,
                             RootWindow(display, 0),
 , 1, width, height,
 ,
                             BlackPixel(display, 0),
                             BlackPixel(display, 0));
     if (! window)
         return 0;
     gc = XCreateGC(display, window, 0, 0);
     if (! gc)
         return 0;
     // Set up a grayscale
     const unsigned int ncolors = sizeof colors / sizeof colors[0];
     const unsigned short step = 65536 / ncolors;
     unsigned short brightness = 0;
     XColor *color = colors;
     XColor *limit = colors + ncolors;
     for (; color < limit; ++color, brightness += step) {
         color->red   = brightness;
         color->green = brightness;
         color->blue  = brightness;
         XAllocColor(display, DefaultColormap(display, 0), color);
     }
     // We want exposes and resizes.
     XSelectInput(display, window, ExposureMask | StructureNotifyMask);
     XMapWindow(display, window);
     XFlush(display);
     return 1;
 }
 /**
  * Age pages that haven't been recently touched.
  */
 static void
 decay()
 {
     int ws_immediate = 0, ws_longterm = 0;
     unsigned char *page = pages;
     unsigned char *limit = pages + (maxpage - minpage) + 1;
     for (; page < limit; ++page) {
         if (opt_working_set) {
             if (*page == 255)
                 ++ws_immediate;
             if (*page)
                 ++ws_longterm;
         }
         if (*page) {
             *page /= 8;
             *page *= 7;
         }
     }
     if (opt_working_set) {
         dec(cout);
         cout << "immediate: " << ws_immediate << " pages, ";
         cout << "longterm: " << ws_longterm << " pages, ";
         cout << "mapped: " << ((maxpage - minpage) + 1) << " pages";
         cout << endl;
     }
 }
 /**
  * Blast the state of our pages to the screen.
  */
 static int
 handle_expose(const XExposeEvent& event)
 {
     //printf("handle_expose(%d, %d, %d, %d)\n", event.x, event.y, event.width, event.height);
     int i = event.x / cellsize;
     int imost = i + event.width / cellsize + 1;
     int j = event.y / cellsize;
     int jmost = j + event.height / cellsize + 1;
     unsigned char *last_cell = pages + maxpage - minpage;
     unsigned char *row = pages + j;
     for (int y = j * cellsize, ymost = jmost * cellsize;
          y < ymost;
          y += cellsize, row += width / cellsize) {
         unsigned char *cell = row + i;
         for (int x = i * cellsize, xmost = imost * cellsize;
              x < xmost;
              x += cellsize, ++cell) {
             unsigned int pixel = (cell <= last_cell) ? colors[*cell].pixel : colors[0].pixel;
             XSetForeground(display, gc, pixel);
             XFillRectangle(display, window, gc, x, y, cellsize - 1, cellsize - 1);
         }
     }
     XFlush(display);
     return 1;
 }
 /**
  * Invalidate the entire window.
  */
 static void
 invalidate_window()
 {
     XExposeEvent event;
     event.x = event.y = 0;
     event.width = width;
     event.height = height;
     handle_expose(event);
 }
 /**
  * Handle a configure event.
  */
 static int
 handle_configure(const XConfigureEvent& event)
 {
     //printf("handle_resize(%d, %d)\n", event.width, event.height);
     width = event.width - event.width % cellsize;
     height = event.height;
     return 1;
 }
 /**
  * Filter to select any message.
  */
 static Bool
 any_event(Display *display, XEvent *event, XPointer arg)
 {
     return 1;
 }
 /**
  * An X event occurred. Process it and flush the queue.
  */
 static int
 handle_xevents()
 {
     int ok;
     XEvent event;
     XNextEvent(display, &event);
     do {
         switch (event.type) {
         case Expose:
             ok = handle_expose(reinterpret_cast<const XExposeEvent&>(event));
             break;
         case ConfigureNotify:
             ok = handle_configure(reinterpret_cast<const XConfigureEvent&>(event));
             break;
         default:
             ok = 1;
         }
     } while (ok && XCheckIfEvent(display, &event, any_event, 0));
     return ok;
 }
 /**
  * Read address data from stdin.
  */
 static int
 read_addrs()
 {
     unsigned int buf[1024];
     ssize_t count;
     while ((count = read(0, buf, sizeof buf)) > 0) {
         if (count % sizeof(unsigned int))
             cerr << "truncating unaligned read" << endl;
         count /= sizeof buf[0];
         unsigned int *addr = reinterpret_cast<unsigned int *>(buf);
         unsigned int *limit = addr + count;
         for (; addr < limit; ++addr) {
             // map the address to a page
             unsigned int page = *addr / PAGESIZE;
             // XXX Don't let stray addresses bring us down. Should
             // really fix this by knowing what the ranges of addresses
             // we ought to expect are (e.g., by reading the symtab)
             if (maxpage && page > maxpage && page - maxpage > MAXPAGES)
                 continue;
             if (! opt_fixed) {
                 // Potentially adjust minpage and maxpage to
                 // accomodate an out-of-bounds address.
                 if (page < minpage) {
                     if (maxpage) {
                         // everything needs to shift.
                         unsigned int shift = minpage - page;
                         memmove(pages + shift, pages, maxpage - minpage);
                         memset(pages, 0, shift);
                     }
                     minpage = page;
                 }
                 if (page > maxpage)
                     maxpage = page;
             }
             page -= minpage;
             pages[page] = 255;
         }
     }
     if (count < 0 && errno != EWOULDBLOCK) {
         perror("read");
         return 0;
     }
     return 1;
 }
 /**
  * Run the program
  */
 static void
 run()
 {
     // We want non-blocking I/O on stdin so we can select on it.
     fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
     // The last time we refreshed the window.
     struct timeval last;
     gettimeofday(&last, 0);
     int ok;
     do {
         // Select on stdin and the connection to the X server.
         fd_set fds;
         FD_ZERO(&fds);
         FD_SET(STDIN_FILENO, &fds);
         FD_SET(GET_DISPLAY_FD(display), &fds);
         struct timeval tv;
         tv.tv_sec  = 1;
         tv.tv_usec = 0;
         ok = select(GET_DISPLAY_FD(display) + 1, &fds, 0, 0, &tv);
         if (ok < 0)
             break;
         if (maxpage) {
             // See if we've waited long enough to refresh the window.
             struct timeval now;
             gettimeofday(&now, 0);
             if (now.tv_sec != last.tv_sec) {
                 // At least a second has gone by. Decay and refresh.
                 last = now;
                 decay();
                 invalidate_window();
             }
             else if (now.tv_usec - last.tv_usec > 100000) {
                 // At least 100msec have gone by. Refresh.
                 last.tv_usec = now.tv_usec;
                 invalidate_window();
             }
         }
         // Now check for X events and input.
         ok = 1;
         if (FD_ISSET(GET_DISPLAY_FD(display), &fds))
             ok = handle_xevents();
         if (FD_ISSET(STDIN_FILENO, &fds))
             ok = read_addrs();
     } while (ok);
 }
 /**
  * Tear down our window and stuff.
  */
 static void
 finish()
 {
     if (window) {
         XUnmapWindow(display, window);
         XDestroyWindow(display, window);
     }
     if (display)
         XCloseDisplay(display);
 }
 static struct option opts[] = {
     { "working-set", no_argument,       0, 'w' },
     { "min",         required_argument, 0, 'm' },
     { "size",        required_argument, 0, 's' },
     { "max",         required_argument, 0, 'x' },
     { 0,             0,                 0, 0   }
 };
 static void
 usage()
 {
     cerr << "thrashview [--working-set] [--min=<min>] [--max=<max>] [--size=<size>]" << endl;
 }
 /**
  * Program starts here.
  */
 int
 main(int argc, char *argv[])
 {
     int size = 0;
     while (1) {
         int option_index = 0;
         int c = getopt_long(argc, argv, "wm:x:s:", opts, &option_index);
         if (c < 0)
             break;
         switch (c) {
         case 'w':
             opt_working_set = true;
             break;
         case 'm':
             minpage = strtol(optarg, 0, 0) / PAGESIZE;
             opt_fixed = true;
             break;
         case 's':
             size = strtol(optarg, 0, 0) / PAGESIZE;
             break;
         case 'x':
             maxpage = strtol(optarg, 0, 0) / PAGESIZE;
             opt_fixed = true;
             break;
         default:
             usage();
             return 1;
         }
     }
     if (minpage && !maxpage) {
         if (!size) {
             cerr << argv[0] << ": minpage specified without maxpage or size" << endl;
             return 1;
         }
         maxpage = minpage + size;
     }
     if (opt_fixed && minpage > maxpage) {
         cerr << argv[0] << ": invalid page range" << endl;
         return 1;
     }
     if (init())
         run();
     finish();
     return 0;
 }

The Tor Browser / annotate

tools/footprint/thrashview.cpp@97036ab72558 (annotated)

tools/footprint/thrashview.cpp