[ext2] Massive EXT2 compatibility commit.

core/alloc.c

@@ -119,14 +119,8 @@
  * Defines for often-used integral values
  * related to our binning and paging strategy.
  */
-#if SIZE_MAX == UINT32_MAX
 #define NUM_BINS 11U								/* Number of bins, total, under 32-bit. */
 #define SMALLEST_BIN_LOG 2U							/* Logarithm base two of the smallest bin: log_2(sizeof(int32)). */
-#else
-#define NUM_BINS 10U								/* Number of bins, total, under 64-bit. */
-#define SMALLEST_BIN_LOG 3U							/* Logarithm base two of the smallest bin: log_2(sizeof(int64)). */
-#endif
-
 #define BIG_BIN (NUM_BINS - 1)						/* Index for the big bin, (NUM_BINS - 1) */
 #define SMALLEST_BIN (1UL << SMALLEST_BIN_LOG)		/* Size of the smallest bin. */
 

core/fs/ext2_initrd.c

@@ -4,6 +4,10 @@
 
 ext2_superblock_t * initrd_superblock;
 ext2_inodetable_t * initrd_root_node;
+ext2_bgdescriptor_t * initrd_root_block;
+ext2_inodetable_t * initrd_inode_table;
+void * initrd_start;
+
 fs_node_t *         initrd_root;
 fs_node_t *         initrd_dev;
 
@@ -14,6 +18,9 @@ void open_initrd(fs_node_t *node, uint8_t read, uint8_t write);
 void close_initrd(fs_node_t *node);
 struct dirent *readdir_initrd(fs_node_t *node, uint32_t index);
 fs_node_t *finddir_initrd(fs_node_t *node, char *name);
+ext2_dir_t * ext2_get_direntry(ext2_inodetable_t * inode, uint32_t index);
+ext2_inodetable_t * ext2_get_inode(uint32_t inode);
+void * ext2_get_block(uint32_t block);
 
 uint32_t
 read_initrd(
@@ -61,16 +68,71 @@ readdir_initrd(
 		fs_node_t *node,
 		uint32_t index
 		) {
+	ext2_inodetable_t * inode = ext2_get_inode(node->inode);
+	ext2_dir_t * direntry = ext2_get_direntry(inode, index);
+	if (!direntry) {
 		return NULL;
 	}
+	struct dirent * dirent = malloc(sizeof(struct dirent));
+	memcpy(&dirent->name, &direntry->name, direntry->name_len);
+	dirent->name[direntry->name_len] = '\0';
+	dirent->ino = direntry->inode;
+	return dirent;
+}
 
+/*
+ * find the child entry named `name` within the directory
+ * node `node`. The VFS has already checked that `node` is
+ * a valid directory, but we'll do that again just to be safe,
+ * and just in case someone didn't use the VFS layer to call us.
+ * Basically, run through the directory entries until we find
+ * the one requested and build an fs_node_t for it. The requester
+ * will have to free it when they are done with it.
+ */
 fs_node_t *
 finddir_initrd(
 		fs_node_t *node,
 		char *name
 		) {
+	/*
+	 * Find the actual inode in the ramdisk image for the requested file
+	 */
+	ext2_inodetable_t * inode = ext2_get_inode(node->inode);
+	void * block;
+	ext2_dir_t * direntry = NULL;
+	block = (void *)ext2_get_block(inode->block[0]);
+	uint32_t dir_offset;
+	dir_offset = 0;
+	/*
+	 * Look through the requested entries until we find what we're looking for
+	 */
+	while (dir_offset < inode->size) {
+		ext2_dir_t * d_ent = (ext2_dir_t *)((uintptr_t)block + dir_offset);
+		if (strlen(name) != d_ent->name_len) {
+			dir_offset += d_ent->rec_len;
+			continue;
+		}
+		char * dname = malloc(sizeof(char) * (d_ent->name_len + 1));
+		memcpy(dname, &d_ent->name, d_ent->name_len);
+		dname[d_ent->name_len] = '\0';
+		if (!strcmp(dname, name)) {
+			free(dname);
+			direntry = d_ent;
+			break;
+		}
+		free(dname);
+		dir_offset += d_ent->rec_len;
+	}
+	if (!direntry) {
+		/*
+		 * We could not find the requested entry in this directory.
+		 */
 		return NULL;
 	}
+	fs_node_t * outnode = malloc(sizeof(fs_node_t));
+	initrd_node_from_file(direntry->inode, direntry, outnode);
+	return outnode;
+}
 
 uint32_t
 initrd_node_from_file(
@@ -93,6 +155,54 @@ initrd_node_from_file(
 	fnode->mask = inode->mode & 0xFFF;
 	/* File Flags */
 	fnode->flags = 0;
+	if (inode->mode & EXT2_S_IFREG) {
+		fnode->flags |= FS_FILE;
+	}
+	if (inode->mode & EXT2_S_IFDIR) {
+		fnode->flags |= FS_DIRECTORY;
+	}
+	if (inode->mode & EXT2_S_IFBLK) {
+		fnode->flags |= FS_BLOCKDEVICE;
+	}
+	if (inode->mode & EXT2_S_IFCHR) {
+		fnode->flags |= FS_CHARDEVICE;
+	}
+	if (inode->mode & EXT2_S_IFIFO) {
+		fnode->flags |= FS_PIPE;
+	}
+	if (inode->mode & EXT2_S_IFLNK) {
+		fnode->flags |= FS_SYMLINK;
+	}
+	fnode->read    = read_initrd;
+	fnode->write   = write_initrd;
+	fnode->open    = open_initrd;
+	fnode->close   = close_initrd;
+	fnode->readdir = readdir_initrd;
+	fnode->finddir = finddir_initrd;
+	return 1;
+}
+
+uint32_t
+initrd_node_from_dirent(
+		ext2_inodetable_t * inode,
+		struct dirent * direntry,
+		fs_node_t * fnode
+		) {
+	if (!fnode) {
+		/* You didn't give me a node to write into, go *** yourself */
+		return 0;
+	}
+	/* Information from the direntry */
+	fnode->inode = direntry->ino;
+	memcpy(&fnode->name, &direntry->name, strlen(direntry->name));
+	fnode->name[strlen(direntry->name)] = '\0';
+	/* Information from the inode */
+	fnode->uid = inode->uid;
+	fnode->gid = inode->gid;
+	fnode->length = inode->size;
+	fnode->mask = inode->mode & 0xFFF;
+	/* File Flags */
+	fnode->flags = 0;
 	if (inode->mode & EXT2_S_IFREG) {
 		fnode->flags &= FS_FILE;
 	}
@@ -117,4 +227,60 @@ initrd_node_from_file(
 	fnode->close   = close_initrd;
 	fnode->readdir = readdir_initrd;
 	fnode->finddir = finddir_initrd;
+	return 1;
+}
+
+ext2_inodetable_t *
+ext2_get_inode(
+		uint32_t inode
+		) {
+	return (ext2_inodetable_t *)((uintptr_t)initrd_inode_table + initrd_superblock->inode_size * (inode - 1));
+}
+
+void *
+ext2_get_block(
+		uint32_t block
+		) {
+	return (void *)((uintptr_t)initrd_start + (1024 << initrd_superblock->log_block_size) * block);
+}
+
+ext2_dir_t *
+ext2_get_direntry(
+		ext2_inodetable_t * inode,
+		uint32_t index
+		) {
+	assert(inode->mode & EXT2_S_IFDIR);
+	void * block;
+	block = (void *)ext2_get_block(inode->block[0]);
+	uint32_t dir_offset;
+	dir_offset = 0;
+	uint32_t dir_index;
+	dir_index = 0;
+	while (dir_offset < inode->size) {
+		ext2_dir_t * d_ent = (ext2_dir_t *)((uintptr_t)block + dir_offset);
+		if (dir_index == index) {
+			return d_ent;
+		}
+		dir_offset += d_ent->rec_len;
+		dir_index++;
+	}
+	return NULL;
+}
+
+void
+initrd_mount(
+		uint32_t mem_head,
+		uint32_t mem_top
+		) {
+	initrd_start = (void *)mem_head;
+	initrd_superblock = (ext2_superblock_t *)((uintptr_t)initrd_start + 1024);
+	assert(initrd_superblock->magic == EXT2_SUPER_MAGIC);
+	initrd_root_block = (ext2_bgdescriptor_t *)((uintptr_t)initrd_start + 1024 + 1024);
+	initrd_inode_table = (ext2_inodetable_t *)((uintptr_t)initrd_start + (1024 << initrd_superblock->log_block_size) * initrd_root_block->inode_table);
+	// Get the second inode
+	ext2_inodetable_t * root_inode = ext2_get_inode(2);
+	ext2_dir_t * root_direntry = ext2_get_direntry(root_inode, 0);
+	initrd_root = (fs_node_t *)malloc(sizeof(fs_node_t));
+	assert(initrd_node_from_file(root_inode, root_direntry, initrd_root));
+	fs_root = initrd_root;
 }

core/system.c

@@ -20,6 +20,26 @@ memcpy(
 	return dest;
 }
 
+int
+strcmp(
+		const char * a,
+		const char * b
+	  ) {
+	uint32_t i = 0;
+	while (1) {
+		if (a[i] < b[i]) {
+			return -1;
+		} else if (a[i] > b[i]) {
+			return 1;
+		} else {
+			if (a[i] == '\0') {
+				return 0;
+			}
+			++i;
+		}
+	}
+}
+
 /*
  * memset
  * Set `count` bytes to `val`.

core/vfs.c

@@ -40,19 +40,55 @@ struct dirent * readdir_fs(fs_node_t *node, uint32_t index) {
 }
 
 fs_node_t *finddir_fs(fs_node_t *node, char *name) {
-	if ((node->flags & 0x07) == FS_DIRECTORY && node->readdir != 0) {
+	if ((node->flags & FS_DIRECTORY) && node->readdir != 0) {
 		return node->finddir(node, name);
 	} else {
 		return (fs_node_t *)NULL;
 	}
 }
 
+/*
+ * Retreive the node for the requested path
+ */
 fs_node_t *
 kopen(
 		const char *filename,
 		uint32_t flags
 	 ) {
 	/* let's do this shit */
+	if (!fs_root) {
+		HALT_AND_CATCH_FIRE("Attempted to kopen() without a filesystem in place.");
+	}
+	if (!filename[0] == '/') {
+		HALT_AND_CATCH_FIRE("Attempted to kopen() a non-absolute path.");
+	}
+	uint32_t path_len = strlen(filename);
+	char * path = (char *)malloc(sizeof(char) * (path_len));
+	memcpy(path, filename, path_len);
+	char * path_offset = path;
+	uint32_t path_depth = 0;
+	while (path_offset < path + path_len) {
+		if (*path_offset == '/') {
+			*path_offset = '\0';
+			path_depth++;
+		}
+		path_offset++;
+	}
+	path[path_len] = '\0';
+	path_offset = path + 1;
+	uint32_t depth;
+	fs_node_t * node_ptr = fs_root;
+	for (depth = 0; depth < path_depth; ++depth) {
+		node_ptr = finddir_fs(node_ptr, path_offset);
+		if (!node_ptr) {
+			free((void *)path);
+			return NULL;
+		} else if (depth == path_depth - 1) {
+			return node_ptr;
+		}
+	}
+	free((void *)path);
+	return NULL;
 }
 
 

include/ext2.h

@@ -149,4 +149,6 @@ struct ext2_dir {
 
 typedef struct ext2_dir ext2_dir_t;
 
+void initrd_mount(uint32_t mem_head, uint32_t mem_top);
+
 #endif

include/system.h

@@ -30,6 +30,7 @@ extern unsigned short *memsetw(unsigned short *dest, unsigned short val, int cou
 extern int strlen(const char *str);
 extern unsigned char inportb (unsigned short _port);
 extern void outportb (unsigned short _port, unsigned char _data);
+int strcmp(const char * a, const char * b);
 
 /* Panic */
 #define HALT_AND_CATCH_FIRE(mesg) halt_and_catch_fire(mesg, __FILE__, __LINE__)
@@ -129,5 +130,6 @@ void heap_install();
 void * __attribute__ ((malloc)) malloc(size_t size);
 void * __attribute__ ((malloc)) realloc(void * ptr, size_t size);
 void * __attribute__ ((malloc)) calloc(size_t nmemb, size_t size);
+void free(void * ptr);
 
 #endif

main.c

@@ -92,6 +92,14 @@ main(struct multiboot *mboot_ptr) {
 	uint32_t module_start = *((uint32_t*)mboot_ptr->mods_addr);
 	uint32_t module_end   = *(uint32_t*)(mboot_ptr->mods_addr+4);
 
+	initrd_mount(module_start, module_end);
+	fs_node_t * test_file = kopen("/hello.txt", NULL);
+	if (!test_file) {
+		kprintf("Couldn't find /hello.txt\n");
+	}
+	kprintf("Found %s at inode %d\n", test_file->name, test_file->inode);
+
+#if 0
 	ext2_superblock_t * superblock = (ext2_superblock_t *)(module_start + 1024);
 	kprintf("Magic is 0x%x\n", (int)superblock->magic);
 	assert(superblock->magic == EXT2_SUPER_MAGIC);
@@ -160,6 +168,7 @@ main(struct multiboot *mboot_ptr) {
 		}
 		kprintf("\n");
 	};
+#endif
 
 	return 0;
 }