more vfs stuff

kernel/include/fs/VFS.h

@@ -12,6 +12,7 @@ namespace VFS
     {
         char name[64];
         uint64_t inode;
+        uint64_t length;
         node_read read_func;
         node_finddir find_func;
     };

kernel/src/fs/VFS.cpp

@@ -1,24 +1,54 @@
+#define MODULE "vfs"
+
 #include "fs/VFS.h"
+#include "log/Log.h"
 
 static VFS::Node* vfs_root;
 
 int32_t VFS::read(Node* node, uint32_t offset, uint32_t length, char* buffer)
 {
-    if (!node) return -1;
-    if (!node->read_func) return -1;
+    if (!node)
+    {
+        kwarnln("read() failed: trying to read from nullptr");
+        return -1;
+    }
+    if (!node->read_func)
+    {
+        kwarnln("read() failed: the chosen node doesn't support reading");
+        return -1;
+    }
 
     return node->read_func(node, offset, length, buffer);
 }
 
 VFS::Node* VFS::open(const char* filename)
 {
-    if (!vfs_root) return 0;
-    if (!vfs_root->find_func) return 0;
+    if (!vfs_root)
+    {
+        kwarnln("open() failed: root not mounted");
+        return 0;
+    }
+    if (!vfs_root->find_func)
+    {
+        kwarnln("open() failed: root doesn't support finding files");
+        return 0;
+    }
 
     return vfs_root->find_func(vfs_root, filename);
 }
 
 void VFS::mount_root(Node* root)
 {
+    if (!root)
+    {
+        kwarnln("mount_root() failed: attempted to mount nullptr");
+        return;
+    }
+    if (vfs_root)
+    {
+        kwarnln("mount_root() failed: root filesystem already mounted");
+        return;
+    }
+    kinfoln("mounting node '%s' as vfs root", root->name);
     vfs_root = root;
 }

kernel/src/init/InitRD.cpp

@@ -152,6 +152,7 @@ void initrd_scan()
         VFS::Node& node = nodes[i];
         node.inode = i;
         node.read_func = initrd_read;
+        node.length = files[i].size;
         strncpy(node.name, files[i].name, sizeof(node.name));
     }
 }
@@ -163,10 +164,13 @@ void InitRD::init()
     kdbgln("physical base at %lx, size %lx, mapped to %p", bootboot.initrd_ptr, bootboot.initrd_size, initrd_base);
     kdbgln("total blocks: %ld", get_total_blocks());
     initrd_scan();
+    initrd_root.length = 0;
     initrd_root.inode = (uint64_t)-1;
     strncpy(initrd_root.name, "initrd", 7);
     initrd_root.find_func = initrd_scan_root;
     VFS::mount_root(&initrd_root);
+    VFS::mount_root(0);
+    VFS::mount_root(&initrd_root);
     kdbgln("mounted initrd at VFS root, total files: %d", total_files);
     initrd_initialized = true;
 }

kernel/src/main.cpp

@@ -162,17 +162,17 @@ extern "C" void _start()
 
     kinfoln("Trying VFS");
 
-    VFS::Node* node = VFS::open("sys/moon.sym");
+    VFS::Node* node = VFS::open("sys/config");
     if (!node) { kerrorln("Unable to find file in VFS"); }
     else
     {
         kinfoln("Found '%s'", node->name);
-        char buffer[256];
-        kinfoln("Reading 255 bytes at offset 128...");
-        int nwritten = VFS::read(node, 128, 255, buffer);
-        kinfoln("Read a total of %d bytes", nwritten);
-        buffer[255] = 0;
+        char* buffer = (char*)kmalloc(node->length + 1);
+        buffer[node->length] = 0;
+        int nread = VFS::read(node, 0, (uint32_t)node->length, buffer);
+        kdbgln("Read %d bytes", nread);
         kinfoln("Read: %s", buffer);
+        kfree(buffer);
     }
 
     PCI::scan([](PCI::Device& dev) {