parasj/mmap

Implementation of mmap on JOS

Basic MMAP On JOS

Implementation of mmap on JOS

COMPILING

make clean
make

TESTING

Run the following commands to test our JOS MMAP implementation

# Basic mmap
make run-testmmap1-nox
# Dynamic Loading test
make run-testmmap2-nox
# Test pgflt on access after unmap
make run-testmmap3-nox
# Test write back if writable file
make run-testmmap4-nox

Implementation

The main implementation is in mmap.c

See:

• mmap function definition
• mmap pgflt handler
• Mechanism for saving pages

Sample mmap call

struct Fd *fd;
int r_open;

size_t length;
void *mmaped_addr;

char *content;
char fread_buf[512];

// First, open file 'lorem' and get the file id.
if ((r_open = open("/lorem", O_RDONLY)) < 0)
  panic("mmap(): opening file failed, ERROR CODE: %d \n", r_open);

// Start testing.
cprintf("\nTest mmaping\n");
length = PGSIZE;
mmaped_addr = mmap(NULL, length, 0, MAP_PRIVATE, r_open, (off_t) 0);

content = (char*) mmaped_addr;

cprintf("=> Read from mmapped region:\n%30s\n", content);
munmap(mmaped_addr, length);