From ec3d2400db15e6911138d88f95cae141a9da2130 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 11 May 2024 20:55:10 +0200
Subject: kernel: remove HANDLE_NULLFS

It was a dumb hack that wasn't even necessary - an error when mounting should
shadow over the mountpoint anyways.
---
 src/cmd/shell/shell.c              |  2 +-
 src/cmd/tests/kernel/miscsyscall.c |  6 +++++-
 src/kernel/handleset.c             | 12 ++----------
 src/kernel/syscalls.c              | 36 +++++++++++++++++++-----------------
 src/libc/fs/misc.c                 |  2 +-
 src/libk/include/camellia/flags.h  |  4 ----
 6 files changed, 28 insertions(+), 34 deletions(-)

(limited to 'src')

diff --git a/src/cmd/shell/shell.c b/src/cmd/shell/shell.c
index 3aeaca1..9afdb5c 100644
--- a/src/cmd/shell/shell.c
+++ b/src/cmd/shell/shell.c
@@ -57,7 +57,7 @@ void run_args(int argc, char **argv, struct redir *redir) {
 		if (argc < 2) {
 			fprintf(stderr, "shadow: missing path\n");
 		} else {
-			_sys_mount(HANDLE_NULLFS, argv[1], strlen(argv[1]));
+			_sys_mount(-1, argv[1], strlen(argv[1]));
 		}
 	} else if (!strcmp(argv[0], "procmnt")) {
 		if (argc < 2) {
diff --git a/src/cmd/tests/kernel/miscsyscall.c b/src/cmd/tests/kernel/miscsyscall.c
index c7ce9e0..1317720 100644
--- a/src/cmd/tests/kernel/miscsyscall.c
+++ b/src/cmd/tests/kernel/miscsyscall.c
@@ -316,7 +316,11 @@ static void test_getnull(void) {
 	test(_sys_getsize(h) == -ENOSYS);
 	test(_sys_remove(h) == -ENOSYS);
 	test(_sys_fs_respond(h, buf, 16, 0) == -EBADF);
-	test(_sys_mount(h, "/asdf", 5) == -EGENERIC);
+
+	/* making some assumptions about the testing environment here... */
+	test(_sys_open("/test", 5, OPEN_READ) != -EGENERIC);
+	test(_sys_mount(h, "/test", 5) == 0);
+	test(_sys_open("/test", 5, OPEN_READ) == -EGENERIC);
 
 	close(h);
 	close(h2);
diff --git a/src/kernel/handleset.c b/src/kernel/handleset.c
index b52eaa0..a25f5c7 100644
--- a/src/kernel/handleset.c
+++ b/src/kernel/handleset.c
@@ -55,15 +55,7 @@ hs_findfree(HandleSet *hs, hid_t start)
 Handle *
 hs_get(HandleSet *hs, hid_t id)
 {
-	if (id == HANDLE_NULLFS) {
-		// TODO get rid of this stupid hack
-		static Handle h = (Handle){
-			.type = HANDLE_FS_FRONT,
-			.backend = NULL,
-			.refcount = 2, /* never free */
-		};
-		return &h;
-	} else if (0 <= id && id < HANDLE_MAX) {
+	if (0 <= id && id < HANDLE_MAX) {
 		return hs->h[id];
 	} else {
 		return NULL;
@@ -107,7 +99,7 @@ Handle *
 hs_take(HandleSet *hs, hid_t hid)
 {
 	if (hid < 0 || hid >= HANDLE_MAX) {
-		return hs_get(hs, hid); // TODO can't this cause HANDLE_NULLFS to be freed?
+		return NULL;
 	}
 	Handle *h = hs->h[hid];
 	hs->h[hid] = NULL;
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index da6b48f..9b0746a 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -63,7 +63,7 @@ hid_t _sys_open(const char __user *path, long len, int flags) {
 	if (flags & ~(OPEN_RW | OPEN_CREATE)) SYSCALL_RETURN(-ENOSYS);
 
 	if (PATH_MAX < len)
-		SYSCALL_RETURN(-1);
+		SYSCALL_RETURN(-ENAMETOOLONG);
 	/* Doesn't check for free handles. Another thread could use up all
 	 * handles in the meantime anyways, or free some up. */
 
@@ -86,16 +86,16 @@ hid_t _sys_open(const char __user *path, long len, int flags) {
 	}
 
 	vfsreq_create((VfsReq) {
-			.type = VFSOP_OPEN,
-			.input = {
-				.kern = true,
-				.buf_kern = path_buf,
-				.len = len,
-			},
-			.caller = proc_cur,
-			.backend = mount->backend,
-			.flags = flags,
-		});
+		.type = VFSOP_OPEN,
+		.input = {
+			.kern = true,
+			.buf_kern = path_buf,
+			.len = len,
+		},
+		.caller = proc_cur,
+		.backend = mount->backend,
+		.flags = flags,
+	});
 	return -1; // dummy
 fail:
 	kfree(path_buf);
@@ -125,12 +125,14 @@ long _sys_mount(hid_t hid, const char __user *path, long len) {
 	}
 
 	Handle *handle = hs_get(proc_cur->hs, hid);
-	if (!handle || handle->type != HANDLE_FS_FRONT)
-		goto fail;
-	backend = handle->backend;
-	if (backend) {
-		assert(backend->usehcnt);
-		backend->usehcnt++;
+	if (handle && handle->type == HANDLE_FS_FRONT) {
+		backend = handle->backend;
+		if (backend) {
+			assert(backend->usehcnt);
+			backend->usehcnt++;
+		}
+	} else {
+		backend = NULL;
 	}
 
 	// append to mount list
diff --git a/src/libc/fs/misc.c b/src/libc/fs/misc.c
index f0925ba..d7013e8 100644
--- a/src/libc/fs/misc.c
+++ b/src/libc/fs/misc.c
@@ -164,7 +164,7 @@ int mount_at(const char *path) {
 		_sys_mount(h, path, strlen(path));
 		close(h);
 	} else {
-		_sys_mount(HANDLE_NULLFS, path, strlen(path));
+		_sys_mount(-1, path, strlen(path));
 	}
 	return ret;
 }
diff --git a/src/libk/include/camellia/flags.h b/src/libk/include/camellia/flags.h
index bc34616..a708f73 100644
--- a/src/libk/include/camellia/flags.h
+++ b/src/libk/include/camellia/flags.h
@@ -28,7 +28,3 @@
  * The idea is that if all flags which allow modifying the filesystem state require
  * OPEN_WRITE to be set, filesystem handlers could just check for the OPEN_WRITE flag. */
 #define OPEN_CREATE 4
-
-
-/* special handles */
-#define HANDLE_NULLFS -2
-- 
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