feat: partially implement PS/2 input subsystem with keyboard and mouse support

This implementation is incomplete, and doesn't work, but it will soon, to be determined, hopefully, uh, yknow.

Signed-off-by kaguya <vpshinomiya@protonmail.com>

src/fs/vfs.c

@@ -2,12 +2,55 @@
 #include <video/render.h>
 #include <arch/x86_64/e9.h>
 #include "mp/spinlock.h"
+#include "stdio.h"
+#include "string.h"
 
 static spinlock_t s_vfs_lock = SPINLOCK_INIT;
 static vfs_file_t vfs_fd_table[VFS_MAX_FDS];
 
+typedef struct {
+    const char* path;
+    int (*read)(void* buf, size_t len);
+    int (*write)(const void* buf, size_t len);
+} vfs_chardev_t;
+
+#define VFS_MAX_CHARDEVS 8
+static vfs_chardev_t s_chardevs[VFS_MAX_CHARDEVS];
+static int s_num_chardevs = 0;
+
+int VFS_RegisterCharDev(const char* path,
+                        int (*read)(void* buf, size_t len),
+                        int (*write)(const void* buf, size_t len))
+{
+    if (s_num_chardevs >= VFS_MAX_CHARDEVS) {
+        printf("VFS: too many char devices!\n");
+        return -1;
+    }
+    s_chardevs[s_num_chardevs].path  = path;
+    s_chardevs[s_num_chardevs].read  = read;
+    s_chardevs[s_num_chardevs].write = write;
+    printf("VFS: registered chardev %s\n", path);
+    s_num_chardevs++;
+    return 0;
+}
+
 fd_t VFS_Open_internal(const char* path)
 {
+    for (int i = 0; i < s_num_chardevs; i++) {
+        if (strcmp(s_chardevs[i].path, path) == 0) {
+            for (int fd = 4; fd < VFS_MAX_FDS; fd++) {
+                if (!vfs_fd_table[fd].used) {
+                    vfs_fd_table[fd].used = true;
+                    vfs_fd_table[fd].type = VFS_NODE_CHARDEV;
+                    vfs_fd_table[fd].offset = 0;
+                    vfs_fd_table[fd].chardev.dev_idx = i;
+                    return fd;
+                }
+            }
+            return -1;
+        }
+    }
+
     uint32_t ino = ext2_resolve_path(path);
     if (ino == 0)
         return -1;
@@ -92,6 +135,14 @@ int VFS_Read(fd_t fd, uint8_t* buf, size_t size)
         return size;
     }
 
+    case VFS_NODE_CHARDEV:
+    {
+        int idx = file->chardev.dev_idx;
+        if (idx < 0 || idx >= s_num_chardevs || !s_chardevs[idx].read)
+            return -1;
+        return s_chardevs[idx].read(buf, size);
+    }
+
     default:
         return -1;
     }
@@ -143,5 +194,13 @@ int VFS_Write(fd_t file, uint8_t* data, size_t size)
         return size;
     }
 
+    if (f->type == VFS_NODE_CHARDEV)
+    {
+        int idx = f->chardev.dev_idx;
+        if (idx >= 0 && idx < s_num_chardevs && s_chardevs[idx].write)
+            return s_chardevs[idx].write(data, size);
+        return -1;
+    }
+
     return -1;
 }