basic mount resolving

5 files changed, 67 insertions, 2 deletions

diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index e1b650c..f826d8a 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -16,6 +16,7 @@ struct process *process_seed() {
 	proc->sibling = NULL;
 	proc->child   = NULL;
 	proc->parent  = NULL;
+	proc->mount   = NULL;
 	proc->id      = next_pid++;
 
 	process_first = proc;
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index c2dfde4..ffc342a 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <kernel/arch/generic.h>
+#include <kernel/vfs/mount.h>
 
 enum process_state {
 	PS_RUNNING,
@@ -25,6 +26,8 @@ struct process {
 	// PS_WAITS4CHILDDEATH - buffer for said message
 	void  *saved_addr;
 	size_t saved_len;
+
+	struct vfs_mount *mount;
 };
 
 extern struct process *process_first;
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 13e0535..0a88c98 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -67,12 +67,13 @@ int _syscall_fork() {
 
 fd_t _syscall_fs_open(const char *path, size_t len) {
 	struct virt_iter iter;
-	static char buffer[PATH_MAX]; // holds the simplified path
+	struct vfs_mount *mount = process_current->mount;
+	static char buffer[PATH_MAX]; // holds the path
 	size_t pos = 0;
 
 	if (len > PATH_MAX) return -1;
 
-	// copy the path to buffer
+	// copy the path to the kernel
 	virt_iter_new(&iter, (void*)path, len, process_current->pages, true, false);
 	while (virt_iter_next(&iter)) {
 		memcpy(buffer + pos, iter.frag, iter.frag_len);
@@ -83,7 +84,55 @@ fd_t _syscall_fs_open(const char *path, size_t len) {
 	len = path_simplify(buffer, buffer, len);
 	if (len < 0) return -1;
 
+	// find mount
+	for (mount = process_current->mount; mount; mount = mount->prev) {
+		if (mount->prefix_len > len)
+			continue;
+		if (memcmp(mount->prefix, buffer, mount->prefix_len) == 0)
+			break;
+	}
+
 	tty_write(buffer, len);
+	tty_const(" from mount ");
+	if (mount)
+		tty_write(mount->prefix, mount->prefix_len);
+	else
+		tty_const("[none]");
+
+	return -1;
+}
+
+int _syscall_mount(const char *path, int len, fd_t fd) {
+	struct virt_iter iter;
+	struct vfs_mount *mount;
+	char *path_buf;
+	size_t pos = 0;
+
+	if (len > PATH_MAX) return -1;
+
+	// copy the path to the kernel
+	virt_iter_new(&iter, (void*)path, len, process_current->pages, true, false);
+	path_buf = kmalloc(len);
+	while (virt_iter_next(&iter)) { // TODO abstract away
+		memcpy(path_buf + pos, iter.frag, iter.frag_len);
+		pos += iter.frag_len;
+	}
+	if (iter.error) goto fail;
+
+	// simplify it
+	len = path_simplify(path_buf, path_buf, len);
+	if (len < 0) goto fail;
+	// TODO remove trailing slash
+
+	// append to mount list
+	mount = kmalloc(sizeof(struct vfs_mount));
+	mount->prev = process_current->mount;
+	mount->prefix = path_buf;
+	mount->prefix_len = len;
+	process_current->mount = mount;
+	return 0;
+fail:
+	kfree(path_buf);
 	return -1;
 }
 
@@ -109,6 +158,8 @@ int syscall_handler(int num, int a, int b, int c) {
 			return _syscall_fork();
 		case _SYSCALL_FS_OPEN:
 			return _syscall_fs_open((void*)a, b);
+		case _SYSCALL_MOUNT:
+			return _syscall_mount((void*)a, b, c);
 		case _SYSCALL_DEBUGLOG:
 			return _syscall_debuglog((void*)a, b);
 		default:
diff --git a/src/kernel/syscalls.h b/src/kernel/syscalls.h
index 5f55454..c8dca05 100644
--- a/src/kernel/syscalls.h
+++ b/src/kernel/syscalls.h
@@ -3,6 +3,7 @@
 #include <stddef.h>
 
 typedef int fd_t;
+typedef int fs_handle_t;
 
 enum {
 	// idc about stable syscall numbers just yet
@@ -11,6 +12,7 @@ enum {
 	_SYSCALL_FORK,
 
 	_SYSCALL_FS_OPEN,
+	_SYSCALL_MOUNT,
 
 	_SYSCALL_DEBUGLOG
 };
@@ -32,6 +34,7 @@ int _syscall_await(char *buf, int len);
 int _syscall_fork();
 
 fd_t _syscall_fs_open(const char *path, size_t len);
+int _syscall_mount(const char *path, int len, fd_t fd);
 
 /** Prints a message to the debug console.
  * @return the amount of bytes written (can be less than len)
diff --git a/src/kernel/vfs/mount.h b/src/kernel/vfs/mount.h
new file mode 100644
index 0000000..b99f97e
--- /dev/null
+++ b/src/kernel/vfs/mount.h
@@ -0,0 +1,7 @@
+#pragma once
+
+struct vfs_mount {
+	struct vfs_mount *prev;
+	char *prefix;
+	size_t prefix_len;
+};