fix opening directories and saving inode_ptr instead of inode in fd

src/fs.c

@@ -1002,33 +1002,45 @@ static void resolve_path(struct resolved_path *rp, char *path, unsigned int para
 }
 
 
+static int find_free_fd(void)
+{
+	for (int i = 0; i < FS_MAX_OPEN_FD; i++)
+		if (!fs_file_descriptions[i].inode)
+			return i;
+
+	return -1;
+}
+
 int fs_open(void *d)
 {
-	char *fname = *((char **) d);
+	char *path = *((char **) d);
 
-	// find file inode
+	struct resolved_path rp;
-	struct fs_file_description fd;
+	resolve_path(&rp, path, FOLLOW_LAST_SYMLINK);
-	{
-		int *r = find_filename_in_directory(fs_cwd_inode_ptr, fname);
-		if (!r) {
-			pr_err("no such file: '%s'\n", fname);
-			return 0;
-		}
 
-		fd.inode = read_inode_ptr(r[2]);
+	if (rp.target_inode_ptr < 0) {
-		free(r);
+		pr_err("no such file: '%s'\n", path);
+		return 0;
 	}
-	fd.rw_offset = 0;
 
-	// find free file descriptor
+	int free_fd = find_free_fd();
-	int free_fd;
+	if (free_fd < 0) {
-	for (free_fd = 0; (free_fd < FS_MAX_OPEN_FD) && (fs_file_descriptions[free_fd].inode); free_fd++);
-	if (free_fd == FS_MAX_OPEN_FD) {
 		pr_err("no free file descriptor found\n");
 		return 0;
 	}
 
-	memcpy(&(fs_file_descriptions[free_fd]), &fd, sizeof(struct fs_file_description));
+	{
+		struct fs_inode i;
+		read_block(read_inode_ptr(rp.target_inode_ptr), &i);
+
+		if (i.ftype == DIRECTORY) {
+			pr_err("can't open '%s': file is a directory\n", rp.target_fname);
+			return 0;
+		}
+	}
+
+	fs_file_descriptions[free_fd].inode = read_inode_ptr(rp.target_inode_ptr);
+	fs_file_descriptions[free_fd].rw_offset = 0;
 
 	pr_stdout("%d\n", free_fd);
 
@@ -1332,7 +1344,7 @@ int fs_write(void *d)
 
 int fs_truncate(void *d)
 {
-	char *fname = *((char **) d);
+	char *path = *((char **) d);
 	int size = *((int *) ((char **) d+1));
 
 	if (size < 0) {
@@ -1340,52 +1352,48 @@ int fs_truncate(void *d)
 		return 0;
 	}
 
-	int file_inode_ptr;
+	struct resolved_path rp;
-	{
+	resolve_path(&rp, path, FOLLOW_LAST_SYMLINK);
-		int *r = find_filename_in_directory(fs_cwd_inode_ptr, fname);
-		if (r == NULL) {
-			pr_err("no such file: '%s'\n", fname);
-			return 0;
-		}
 
-		file_inode_ptr = r[2];
+	if (rp.target_inode_ptr < 0) {
-		free(r);
+		pr_err("no such file: '%s'\n", path);
+		return 0;
 	}
 
-	struct fs_inode f;
+	struct fs_inode inode;
-	read_block(read_inode_ptr(file_inode_ptr), (void *) &f);
+	read_block(read_inode_ptr(rp.target_inode_ptr), &inode);
 
-	if (size > f.size) {
+	if (size > inode.size) {
-		pr("Increasing file size of '%s': %d -> %d\n", fname, f.size, size);
+		pr("Increasing file size of '%s': %d -> %d\n", rp.target_fname, inode.size, size);
-		f.size = size;
+		inode.size = size;
-		write_block(read_inode_ptr(file_inode_ptr), (void *) &f);
+		write_block(read_inode_ptr(rp.target_inode_ptr), &inode);
 	} else {
-		pr("Decreasing file size of '%s': %d -> %d\n", fname, f.size, size);
+		pr("Decreasing file size of '%s': %d -> %d\n", rp.target_fname, inode.size, size);
-		f.size = size;
+		inode.size = size;
 
 		// cleanup
-		int new_block_amount = f.size / FS_BLOCK_SIZE;
+		int new_block_amount = inode.size / FS_BLOCK_SIZE;
-		if (f.size % FS_BLOCK_SIZE)
+		if (inode.size % FS_BLOCK_SIZE)
 			new_block_amount++;
 
 		int blocks_seen = 0;
 
 		// look through base inode blocks
 		for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE; i++, blocks_seen++) {
-			if ((blocks_seen >= new_block_amount) && (f.blocks[i])) {
+			if ((blocks_seen >= new_block_amount) && (inode.blocks[i])) {
-				mark_free(f.blocks[i]);
+				mark_free(inode.blocks[i]);
-				f.blocks[i] = 0;
+				inode.blocks[i] = 0;
 			}
 		}
-		write_block(read_inode_ptr(file_inode_ptr), (void *) &f);
+		write_block(read_inode_ptr(rp.target_inode_ptr), &inode);
 
 		// look through inode extension blocks
 		struct fs_inode_extension ext;
-		unsigned int next_ext = f.next_extension;
+		unsigned int next_ext = inode.next_extension;
 		unsigned int curr_ext;
 
 		while (next_ext) {
-			read_block(next_ext, (void *) &ext);
+			read_block(next_ext, &ext);
 
 			for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE_EXTENSION; i++, blocks_seen++) {
 				if ((blocks_seen >= new_block_amount) && (ext.blocks[i])) {
@@ -1394,25 +1402,25 @@ int fs_truncate(void *d)
 				}
 			}
 
-			write_block(next_ext, (void *) &ext);
+			write_block(next_ext, &ext);
 			next_ext = ext.next_extension;
 		}
 
 		// look through inode extensions themselves
-		int required_blocks_after_base_inode = (int) f.size - (int) BLOCK_ADDRESSES_PER_INODE;
+		int required_blocks_after_base_inode = (int) inode.size - (int) BLOCK_ADDRESSES_PER_INODE;
 		int required_extensions = required_blocks_after_base_inode >= 0
 			? required_blocks_after_base_inode / BLOCK_ADDRESSES_PER_INODE_EXTENSION
 			: 0;
 
-		if ((f.size - BLOCK_ADDRESSES_PER_INODE) % BLOCK_ADDRESSES_PER_INODE_EXTENSION)
+		if ((inode.size - BLOCK_ADDRESSES_PER_INODE) % BLOCK_ADDRESSES_PER_INODE_EXTENSION)
 			required_extensions++;
 
-		next_ext = f.next_extension;
+		next_ext = inode.next_extension;
 
 		if (!required_extensions) {
 			// zero base inode next_extension ptr
-			f.next_extension = 0;
+			inode.next_extension = 0;
-			write_block(read_inode_ptr(file_inode_ptr), (void *) &f);
+			write_block(read_inode_ptr(rp.target_inode_ptr), &inode);
 		} else {
 			// seek to last required extension
 			for (int i = 0; i < required_extensions; i++) {
@@ -1420,19 +1428,19 @@ int fs_truncate(void *d)
 					return 0;
 
 				curr_ext = next_ext;
-				read_block(curr_ext, (void *) &ext);
+				read_block(curr_ext, &ext);
 				next_ext = ext.next_extension;
 			}
 
 			// remove next_extension ptr
 			ext.next_extension = 0;
-			write_block(curr_ext, (void *) &ext);
+			write_block(curr_ext, &ext);
 		}
 
 		// erase all remaining extensions
 		while (next_ext) {
 			mark_free(next_ext);
-			read_block(next_ext, (void *) &ext);
+			read_block(next_ext, &ext);
 			next_ext = ext.next_extension;
 		}
 	}
@@ -1546,108 +1554,63 @@ int fs_create(void *d)
 
 int fs_ln(void *d)
 {
-	if (used_file_fd <= 0) {
+	char *prev_path = ((char **) d)[0];
-		pr_err("no storage device\n");
+	char *new_path = ((char **)d)[1];
-		return 0;
-	}
-
-	char *existing_fname = ((char **) d)[0];
-	char *new_fname = ((char **)d)[1];
-	int new_fname_len = strlen(new_fname);
 
+	char new_fname[FS_MAX_FNAME_LEN+1];
 	{
-		// check if duplicate filename exists in current directory
+		int new_fname_len = extract_basename(new_path, new_fname);
-		int *r = find_filename_in_directory(fs_cwd_inode_ptr, new_fname);
+		if (new_fname_len > FS_MAX_FNAME_LEN) {
-		if (r) {
+			pr_err("new filename too long (%d > %d)\n", new_fname_len, FS_MAX_FNAME_LEN);
-			free(r);
-			pr_err("filename '%s' already exists\n", new_fname);
 			return 0;
 		}
 	}
 
+	struct resolved_path prev_rp, new_rp;
 
-	if (new_fname_len > FS_MAX_FNAME_LEN) {
+	resolve_path(&prev_rp, prev_path, 0);
-		pr_err("new filename too long (%d > %d)\n", new_fname_len, FS_MAX_FNAME_LEN);
+	if (prev_rp.target_inode_ptr < 0) {
+		pr_err("no such file: '%s'\n", prev_path);
 		return 0;
 	}
 
-	pr("Making hard link '%s' -> '%s'\n", new_fname, existing_fname);
+	{
+		struct fs_inode prev_i;
+		read_block(read_inode_ptr(prev_rp.target_inode_ptr), &prev_i);
 
-	// find original file name
+		if (prev_i.ftype == DIRECTORY) {
-	unsigned int original_inode_ptr = 0;
+			pr_err("refusing to create hard link for directory\n");
-
+			return 0;
-	int dir_inode = read_inode_ptr(fs_cwd_inode_ptr);
-
-	struct fs_inode dir;
-	read_block(dir_inode, (void *) &dir);
-
-	// list entries from base inode
-	for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE; i++) {
-		struct fs_directory_record recs[DIRECTORY_RECORDS_PER_BLOCK];
-
-		if (dir.blocks[i]) {
-			read_block(dir.blocks[i], (void *) &recs);
-
-			for (int k = 0; k < DIRECTORY_RECORDS_PER_BLOCK; k++) {
-				if (!recs[k].inode_no)
-					continue;
-
-				if (!strcmp(existing_fname, recs[k].fname)) {
-					original_inode_ptr = recs[k].inode_no;
-					goto original_inode_ptr_found;
-				}
-			}
 		}
 	}
 
-	// list entries from inode extensions
+	resolve_path(&new_rp, new_path, 1);
-	struct fs_inode_extension ext;
+	if (new_rp.parent_inode_ptr < 0) {
-	unsigned int next_ext = dir.next_extension;
+		pr_err("failed to create hard link: no such directory: '%s'\n", new_path);
-
+		return 0;
-	while (next_ext) {
+	} else if (new_rp.target_inode_ptr >= 0) {
-		read_block(next_ext, (void *) &ext);
+		pr_err("file already exists: '%s'\n", new_rp.target_fname);
-		next_ext = ext.next_extension;
+		return 0;
-
-		for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE_EXTENSION; i++) {
-			struct fs_directory_record recs[DIRECTORY_RECORDS_PER_BLOCK];
-
-			if (dir.blocks[i]) {
-				read_block(ext.blocks[i], (void *) &recs);
-
-				for (int k = 0; k < DIRECTORY_RECORDS_PER_BLOCK; k++) {
-					if (!recs[k].inode_no)
-						continue;
-
-					if (!strcmp(existing_fname, recs[k].fname)) {
-						original_inode_ptr = recs[k].inode_no;
-						goto original_inode_ptr_found;
-					}
-				}
-			}
-		}
 	}
 
-	pr_err("no such file '%s'\n", existing_fname);
+	pr("Making hard link '%s' -> '%s'\n", new_path, prev_path);
-	return 0;
 
-original_inode_ptr_found:
+	if (fs_add_fname_to_directory(new_rp.parent_inode_ptr, prev_rp.target_inode_ptr, new_fname) < 0) {
-	pr("Original inode_ptr found (%d)\n", original_inode_ptr);
+		pr_err("failed to add filename to directory '%s' (inode_ptr=%d)\n",
-
+				new_rp.parent_fname, new_rp.parent_inode_ptr);
-	// register new filename with the same inode_ptr
-	if (fs_add_fname_to_directory(fs_cwd_inode_ptr, original_inode_ptr, new_fname) < 0) {
-		pr_err("failed to register filename in directory '%s'\n", fs_cwd);
 		return 0;
 	} else {
-		pr("Registered new filename in directory '%s'\n", fs_cwd);
+		pr("Added new filename to directory '%s' (inode_ptr=%d)\n",
+				new_rp.parent_fname, new_rp.parent_inode_ptr);
 	}
 
 	// update ref_count in file inode
-	struct fs_inode f;
+	struct fs_inode i;
-	read_block(read_inode_ptr(original_inode_ptr), (void *) &f);
+	read_block(read_inode_ptr(prev_rp.target_inode_ptr), &i);
-	f.ref_count++;
+	i.ref_count++;
-	write_block(read_inode_ptr(original_inode_ptr), (void *) &f);
+	write_block(read_inode_ptr(prev_rp.target_inode_ptr), &i);
 
-	pr("Updated inode ref_count (%d -> %d)\n", f.ref_count-1, f.ref_count);
+	pr("Updated inode ref_count (%d -> %d)\n", i.ref_count-1, i.ref_count);
 
 	return 0;
 }
@@ -1677,7 +1640,9 @@ static int extract_basename(char *path, char *name)
 		return -1;
 	}
 
-	strcpy(name, &(path[lsp+1]));
+	// allow the usage of NULL ptr to discard basename string
+	if (name)
+		strcpy(name, &(path[lsp+1]));
 
 	return fname_len;
 }
@@ -2188,23 +2153,25 @@ int fs_la(void *d)
 
 int fs_stat(void *d)
 {
-	char *fname = *((char **) d);
+	char *path = *((char **) d);
 
-	int file_inode_ptr = find_fname_in_directory(fs_cwd_inode_ptr, fname);
+	struct resolved_path rp;
-	if (file_inode_ptr < 0) {
+	resolve_path(&rp, path, 0);
-		pr_err("no such file: '%s'\n", fname);
+
+	if (rp.target_inode_ptr < 0) {
+		pr_err("no such file: '%s'\n", path);
 		return 0;
 	}
 
-	struct fs_inode f;
+	struct fs_inode i;
-	read_block(read_inode_ptr(file_inode_ptr), (void *) &f);
+	read_block(read_inode_ptr(rp.target_inode_ptr), &i);
 
-	if (f.ftype == DIRECTORY) {
+	if (i.ftype == DIRECTORY) {
 		pr_stdout("inode_ptr=%d -> inode=%d\nref_count=%d\nsize=%d\ntype=dir\n",
-				file_inode_ptr, read_inode_ptr(file_inode_ptr), f.ref_count, f.size);
+				rp.target_inode_ptr, read_inode_ptr(rp.target_inode_ptr), i.ref_count, i.size);
 	} else {
 		pr_stdout("inode_ptr=%d -> inode=%d\nref_count=%d\nsize=%d\ntype=reg\n",
-				file_inode_ptr, read_inode_ptr(file_inode_ptr), f.ref_count, f.size);
+				rp.target_inode_ptr, read_inode_ptr(rp.target_inode_ptr), i.ref_count, i.size);
 	}
 
 	return 0;