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Code Issues Releases Wiki Activity

Fix filesystem implementation

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This commit is contained in:
Daniel Hillerström
2020-10-01 00:12:51 +01:00
parent aec477f03b
commit 6780352ce9
1 changed files with 35 additions and 8 deletions
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43
code/unix.links
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@@ -148,7 +148,7 @@ fun runState(st0, m) {
sig stdin : FileDescr
var stdin = 0;
sig stderr : FileDescr
var stderr = 3;
var stderr = 2;
sig eof : String
var eof = "\x00";
@@ -161,6 +161,9 @@ typename Mode = [|Create|Append|];
sig fopen : (Mode, String) {Fopen:(Mode, String) -> FileDescr |_}-> FileDescr
fun fopen(mode, filename) { do Fopen(mode, filename) }
sig fclose : (FileDescr) {Fclose:(FileDescr) -> () |_}-> ()
fun fclose(fd) { do Fclose(fd) }
typename File = Queue.T(String);
sig emptyFile : File
@@ -197,7 +200,7 @@ fun defaultFileSystem() {
sig lookupFile : (FileDescr, FileSystem) ~> File
fun lookupFile(fd, fsys) {
switch (lookup(fd, fsys.ft)) {
case Nothing -> error("No such file")
case Nothing -> error("err: No such file(" ^^ intToString(fd) ^^ ")")
case Just(file) -> file
}
}
@@ -210,18 +213,19 @@ fun replaceFile(fd, file, fsys) {
sig createFile : (String, FileSystem) -> (FileDescr, FileSystem)
fun createFile(filename, fsys) {
(fsys.next, (fsys with fs = (filename, fsys.next) :: fsys.fs, next = fsys.next + 1))
var fd = fsys.next;
(fd, (next = fd + 1, fs = (filename, fd) :: fsys.fs, ft = (fd, emptyFile) :: fsys.ft))
}
sig openFile : (Mode, String, FileSystem) ~> (FileDescr, FileSystem)
fun openFile(mode, filename, fsys) {
var (fd, fsys) = switch (lookup(filename, fsys.fs)) {
var (fd, fsys') = switch (lookup(filename, fsys.fs)) {
case Nothing -> createFile(filename, fsys)
case Just(fd) -> (fd, fsys)
};
switch (mode) {
case Create -> error("erase")
case Append -> (fd, fsys)
case Append -> (fd, fsys')
}
}
@@ -233,7 +237,7 @@ fun closeFile((=front,=rear)) {
sig allowState : (() {Get-,Put- |e}~> a) -> () {Get:s,Put:(s) -> () |e}~> a
fun allowState(f) { (f : (() {Get:s,Put:(s) -> () |e}~> a) <- (() {Get-,Put- |e}~> a)) }
sig fileIO : (Comp(a, {Get-,Put-,Gets:(FileDescr) -> String,Puts:(FileDescr,String) -> (),Fopen:(Mode,String) -> FileDescr |e})) {Get:() {}-> FileSystem,Put:(FileSystem) -> (),Gets{_},Puts{_},Fopen{_} |e}~> a
sig fileIO : (Comp(a, {Get-,Put-,Gets:(FileDescr) -> String,Puts:(FileDescr,String) -> (),Fclose:(FileDescr) -> (),Fopen:(Mode,String) -> FileDescr |e})) {Get:() {}-> FileSystem,Put:(FileSystem) -> (),Gets{_},Puts{_},Fclose{_},Fopen{_} |e}~> a
fun fileIO(m) {
handle(allowState(m)()) {
case Gets(fd, resume) ->
@@ -248,6 +252,10 @@ fun fileIO(m) {
var fsys = get();
var (fd, fsys') = openFile(mode, filename, fsys);
put(fsys'); resume(fd)
case Fclose(fd, resume) ->
var fsys = get();
var fsys' = replaceFile(fd, closeFile(lookupFile(fd, fsys)), fsys);
put(fsys'); resume(())
}
}
@@ -361,12 +369,31 @@ fun init() {
})
}
sig init' : (FileSystem) {Fopen{_},Fork{_},Get{_},Getenv{_},Gets{_},Put{_},Puts{_},Su{_},Yield{_}|_}~> ((), FileSystem)
sig example' : () {Fork:Bool,Fclose:(FileDescr) -> (),Fopen:(Mode,String) -> FileDescr,Getenv:(String) -> String,Su:(User) -> (),Puts:(FileDescr,String) -> (),Yield:() |_}~> ()
fun example'() {
var pid = fork();
var () = {
if (pid) redirect(fun(){puts(stdout, "dummy")}, stderr)
else if (fork()) su(Alice)
else su(Bob)
};
var user = whoami();
var fd = fopen(Append, user ^^ ".txt");
puts(fd, "Hello World!");
var uid = getenv("UID");
echo("My UID is " ^^ uid);
(if (amiroot()) { yield(); echo(user ^^ " is running as root.") } else ());
echo("My home dir is /home/" ^^ user);
fclose(fd)
}
sig init' : (FileSystem) {Fclose{_},Fopen{_},Fork{_},Get{_},Getenv{_},Gets{_},Put{_},Puts{_},Su{_},Yield{_}|_}~> ((), FileSystem)
fun init'(fsys) {
runState(fsys, fun() {
fileIO(fun() {
schedule(fun() {
usermgr(Root, envs, example)
usermgr(Root, envs, example')
})
})
})