pintos-doxygen/html/mmap-clean_8c_source.html

/** Verifies that mmap'd regions are only written back on munmap

   if the data was actually modified in memory. */


#include <string.h>

#include <syscall.h>

#include "tests/vm/sample.inc"

#include "tests/lib.h"

#include "tests/main.h"


void

test_main (void)

{

  static const char overwrite[] = "Now is the time for all good...";

  static char buffer[sizeof sample - 1];

  char *actual = (char *) 0x54321000;

  int handle;

  mapid_t map;


  /* Open file, map, verify data. */

  CHECK ((handle = open ("sample.txt")) > 1, "open \"sample.txt\"");

  CHECK ((map = mmap (handle, actual)) != MAP_FAILED, "mmap \"sample.txt\"");

  if (memcmp (actual, sample, strlen (sample)))

    fail ("read of mmap'd file reported bad data");


  /* Modify file. */

  CHECK (write (handle, overwrite, strlen (overwrite))

         == (int) strlen (overwrite),

         "write \"sample.txt\"");


  /* Close mapping.  Data should not be written back, because we

     didn't modify it via the mapping. */

  msg ("munmap \"sample.txt\"");

  munmap (map);


  /* Read file back. */

  msg ("seek \"sample.txt\"");

  seek (handle, 0);

  CHECK (read (handle, buffer, sizeof buffer) == sizeof buffer,

         "read \"sample.txt\"");


  /* Verify that file overwrite worked. */

  if (memcmp (buffer, overwrite, strlen (overwrite))

      || memcmp (buffer + strlen (overwrite), sample + strlen (overwrite),

                 strlen (sample) - strlen (overwrite)))

    {

      if (!memcmp (buffer, sample, strlen (sample)))

        fail ("munmap wrote back clean page");

      else

        fail ("read surprising data from file");

    }

  else

    msg ("file change was retained after munmap");

}

buffer
static struct intq buffer
Stores keys from the keyboard and serial port.
Definition: input.c:7

mmap
mapid_t mmap(int fd, void *addr)
Project 3 and optionally project 4.
Definition: syscall.c:145

open
int open(const char *file)
Definition: syscall.c:103

write
int write(int fd, const void *buffer, unsigned size)
Definition: syscall.c:121

seek
void seek(int fd, unsigned position)
Definition: syscall.c:127

read
int read(int fd, void *buffer, unsigned size)
Definition: syscall.c:115

munmap
void munmap(mapid_t mapid)
Definition: syscall.c:151

MAP_FAILED
#define MAP_FAILED
Definition: syscall.h:13

mapid_t
int mapid_t
Map region identifier.
Definition: syscall.h:12

fail
void fail(const char *format,...)
Definition: lib.c:40

msg
void msg(const char *format,...)
Definition: lib.c:28

lib.h

CHECK
#define CHECK(SUCCESS,...)
Takes an expression to test for SUCCESS and a message, which may include printf-style arguments.
Definition: lib.h:29

main.h

test_main
void test_main(void)
Verifies that mmap'd regions are only written back on munmap if the data was actually modified in mem...
Definition: mmap-clean.c:11

memcmp
int memcmp(const void *a_, const void *b_, size_t size)
Find the first differing byte in the two blocks of SIZE bytes at A and B.
Definition: string.c:53

strlen
size_t strlen(const char *string)
Returns the length of STRING.
Definition: string.c:293

string.h