projects 3 and 4, but it is not strictly required.
You might find it useful to go back and reread how to run the tests
-(@pxref{Testing}). In particular, the tests for project 2 and later
-projects will probably run faster if you use the qemu emulator, e.g.@:
-via @code{make check PINTOSOPTS='--qemu'}. The qemu emulator is
-available only on the Linux machines.
+(@pxref{Testing}).
@menu
* Project 2 Background::
Pintos, kernel virtual memory is mapped one-to-one to physical
memory, starting at @code{PHYS_BASE}. That is, virtual address
@code{PHYS_BASE} accesses physical
-address 0, virtual address @code{PHYS_BASE} + @t{0x1234} access
+address 0, virtual address @code{PHYS_BASE} + @t{0x1234} accesses
physical address @t{0x1234}, and so on up to the size of the machine's
physical memory.
access memory at an unmapped user virtual address
will cause a page fault.
-You must handle memory fragmentation gracefully, that is, a process that
-needs @var{N} pages of user virtual memory must not require those pages
-to be contiguous in physical memory (or, equivalently, in kernel virtual
-memory).
-
@menu
* Typical Memory Layout::
@end menu
on. That is, @code{process_execute("grep foo bar")} should run
@command{grep} passing two arguments @code{foo} and @code{bar}.
-Within a command line, multiple spaces are equivalent to a single space,
-so that @code{process_execute("grep foo bar")} is equivalent to our
-original example. You can impose a reasonable limit on the length of
-the command line arguments. For example, you could limit the arguments
-to those that will fit in a single page (4 kB). (There is an unrelated
-limit of 128 bytes on command-line arguments that the @command{pintos}
-utility can pass to the kernel.)
+Within a command line, multiple spaces are equivalent to a single
+space, so that @code{process_execute("grep @w{ }foo @w{ }@w{ }bar")}
+is equivalent to our original example. You can impose a reasonable
+limit on the length of the command line arguments. For example, you
+could limit the arguments to those that will fit in a single page (4
+kB). (There is an unrelated limit of 128 bytes on command-line
+arguments that the @command{pintos} utility can pass to the kernel.)
You can parse argument strings any way you like. If you're lost,
look at @func{strtok_r}, prototyped in @file{lib/string.h} and
@end deftypefn
@deftypefn {System Call} int wait (pid_t @var{pid})
-Waits for process @var{pid} to die and returns the status it passed to
-@code{exit}. Returns -1 if @var{pid}
+If process @var{pid} is still alive, waits until it dies.
+Then, returns the status that @var{pid} passed to @code{exit},
+or -1 if @var{pid}
was terminated by the kernel (e.g.@: killed due to an exception). If
-@var{pid} is does not refer to a child of the
+@var{pid} does not refer to a child of the
calling thread, or if @code{wait} has already been successfully
called for the given @var{pid}, returns -1 immediately, without
waiting.
@deftypefn {System Call} bool create (const char *@var{file}, unsigned @var{initial_size})
Creates a new file called @var{file} initially @var{initial_size} bytes
in size. Returns true if successful, false otherwise.
+Opening the new file is a separate operation using the @code{open}
+system call.
@end deftypefn
@deftypefn {System Call} bool remove (const char *@var{file})
Deletes the file called @var{file}. Returns true if successful, false
otherwise.
+A file may be removed regardless of whether it is open or closed
+(@pxref{Removing an Open File}, for more information).
@end deftypefn
@deftypefn {System Call} int open (const char *@var{file})
Each process has an independent set of file descriptors. File
descriptors are not inherited by child processes.
+
+When a single file is opened more than once, whether by a single
+process or different processes, each @code{open} returns a new file
+descriptor. Different file descriptors for a single file are closed
+independently in separate calls to @code{close} and they do not share
+a file position.
@end deftypefn
@deftypefn {System Call} int filesize (int @var{fd})
@var{buffer}. Returns the number of bytes actually read (0 at end of
file), or -1 if the file could not be read (due to a condition other
than end of file). Fd 0 reads from the keyboard using
-@func{kbd_getc}. (Keyboard input will not work if you pass the
-@option{-v} option to @command{pintos}.)
+@func{input_getc}.
@end deftypefn
@deftypefn {System Call} int write (int @var{fd}, const void *@var{buffer}, unsigned @var{size})
@code{pid_t}. By default, they're both @code{int}. You can make them
a one-to-one mapping, so that the same values in both identify the
same process, or you can use a more complex mapping. It's up to you.
-
-@item Keyboard input doesn't work.
-
-You are probably passing @option{-v} to @command{pintos}, but
-serial input isn't implemented. Don't use @option{-v} if you
-want to use the shell or otherwise need keyboard input.
@end table
@menu
projects / pintos-anon / blobdiff