add CSD$ and CHDIR

include/taskswitch.h

@@ -21,21 +21,22 @@ typedef uint32_t gid_t;		// Group ID
 typedef uint8_t cpu_id_t;	// CPU ID
 
 typedef struct process_t {
-	pid_t		pid;		/* Process ID */
-	pid_t		ppid;		/* Parent Process ID */
-	uid_t		uid;		/* User id - Future use */
-	gid_t		gid;		/* Group id - Future use */
-	process_state_t	state;		/* Running state */
-	time_t		start_time;	/* Start time (UNIX epoch)*/
-	pid_t		waitpid;	/* PID we are waiting on compltion of */
-	cpu_id_t	cpu;		/* CPU ID */
-	const char*	directory;	/* Directory of program */
-	const char*	name;		/* Filename of program */
-	uint64_t	size;		/* Size of program in bytes */
-	struct console*		cons;	/* Program's console */
-	struct ubasic_ctx*	code;	/* BASIC context */
-	struct process_t*	prev;	/* Prev process in doubly linked list */
-	struct process_t*	next;	/* Next process in doubly linked list */
+	pid_t			pid;		/* Process ID */
+	pid_t			ppid;		/* Parent Process ID */
+	uid_t			uid;		/* User id - Future use */
+	gid_t			gid;		/* Group id - Future use */
+	process_state_t		state;		/* Running state */
+	time_t			start_time;	/* Start time (UNIX epoch)*/
+	pid_t			waitpid;	/* PID we are waiting on compltion of */
+	cpu_id_t		cpu;		/* CPU ID */
+	const char*		directory;	/* Directory of program */
+	const char*		name;		/* Filename of program */
+	uint64_t		size;		/* Size of program in bytes */
+	const char*		csd;		/* Current selected directory */
+	struct console*		cons;		/* Program's console */
+	struct ubasic_ctx*	code;		/* BASIC context */
+	struct process_t*	prev;		/* Prev process in doubly linked list */
+	struct process_t*	next;		/* Next process in doubly linked list */
 } process_t;
 
 /**
@@ -73,9 +74,10 @@ typedef struct idle_timer {
  * @param fullpath fully qualified path to file
  * @param cons console
  * @param parent_pid parent PID, or 0
+ * @param csd Currently selected directory
  * @return process_t* new process details
  */
-process_t* proc_load(const char* fullpath, struct console* cons, pid_t parent_pid);
+process_t* proc_load(const char* fullpath, struct console* cons, pid_t parent_pid, const char* csd);
 
 /**
  * @brief Find a process by ID
@@ -171,5 +173,16 @@ pid_t proc_id(int64_t index);
  */
 void proc_register_idle(proc_idle_timer_t handler, idle_type_t type);
 
+/**
+ * @brief Change CSD (currently selected directory) of process
+ * 
+ * @note No validation of the path is peformed, this must be done
+ * extnerally to this function by validating the file information on VFS.
+ * @param proc Process struct
+ * @param csd current directory
+ * @return const char* new current directory
+ */
+const char* proc_set_csd(process_t* proc, const char* csd);
+
 void init_process();
 

include/tokenizer.h

@@ -121,6 +121,7 @@
 	T(PUSH) \
 	T(POP) \
 	T(LOCAL) \
+	T(CHDIR) \
 	T(MOUNT)
 
 /*

include/ubasic.h

@@ -550,6 +550,7 @@ char* ubasic_insocket(struct ubasic_ctx* ctx);
 char* ubasic_upper(struct ubasic_ctx* ctx);
 char* ubasic_lower(struct ubasic_ctx* ctx);
 char* ubasic_tokenize(struct ubasic_ctx* ctx);
+char* ubasic_csd(struct ubasic_ctx* ctx);
 
 /*
  * File I/O functions
@@ -565,6 +566,7 @@ void mkdir_statement(struct ubasic_ctx* ctx);
 void mount_statement(struct ubasic_ctx* ctx);
 void rmdir_statement(struct ubasic_ctx* ctx);
 void write_statement(struct ubasic_ctx* ctx);
+void chdir_statement(struct ubasic_ctx* ctx);
 
 /*
  * Builtin real (double) functions

src/taskswitch.c

@@ -41,7 +41,7 @@ uint32_t process_count = 0;
  */
 idle_timer_t* task_idles = NULL, *timer_idles = NULL;
 
-process_t* proc_load(const char* fullpath, struct console* cons, pid_t parent_pid)
+process_t* proc_load(const char* fullpath, struct console* cons, pid_t parent_pid, const char* csd)
 {
 	fs_directory_entry_t* fsi = fs_get_file_info(fullpath);
 	if (fsi != NULL && !(fsi->flags & FS_DIRECTORY)) {
@@ -61,6 +61,7 @@ process_t* proc_load(const char* fullpath, struct console* cons, pid_t parent_pi
 			newproc->name = strdup(fsi->filename);
 			newproc->pid = nextid++;
 			newproc->directory = strdup(fullpath);
+			newproc->csd = strdup(csd);
 			newproc->size = fsi->size;
 			newproc->start_time = time(NULL);
 			newproc->state = PROC_RUNNING;
@@ -145,6 +146,39 @@ void proc_wait(process_t* proc, pid_t otherpid)
 	proc->waitpid = otherpid;
 }
 
+const char* proc_set_csd(process_t* proc, const char* csd)
+{
+	if (!csd || !*csd || !proc) {
+		return NULL;
+	}
+
+	size_t len = strlen(proc->csd), csdlen = strlen(csd);
+
+	if (*csd == '/') {
+		kfree(proc->csd);
+		proc->csd = strdup(csd);
+		dprintf("Process %d CSD set to: '%s'\n", proc->pid, proc->csd);
+		return proc->csd;
+	}
+
+	proc->csd = krealloc((void*)proc->csd, len + csdlen + 1);
+	strlcpy((char*)(proc->csd + len), csd, len + csdlen + 1);
+	char* end = (char*)proc->csd + csdlen;
+	if (*end == '/') {
+		*end = 0;
+	}
+	dprintf("Process %d CSD set to: '%s'\n", proc->pid, proc->csd);
+	return proc->csd;
+}
+
+const char* proc_get_csd(process_t* proc)
+{
+	if (!proc) {
+		return "";
+	}
+	return proc->csd;
+}
+
 void proc_kill(process_t* proc)
 {
 	for (process_t* cur = proc_list; cur; cur = cur->next) {
@@ -174,6 +208,7 @@ void proc_kill(process_t* proc)
 	ubasic_destroy(proc->code);
 	kfree(proc->name);
 	kfree(proc->directory);
+	kfree(proc->csd);
 	hashmap_delete(process_by_pid, &(proc_id_t){ .id = proc->pid });
 	kfree(proc);
 	process_count--;
@@ -239,7 +274,7 @@ int process_compare(const void *a, const void *b, void *udata) {
 void init_process()
 {
 	process_by_pid = hashmap_new(sizeof(proc_id_t), 0, 704830503, 487304583058, process_hash, process_compare, NULL, NULL);
-	process_t* init = proc_load("/programs/init", (struct console*)current_console, 0);
+	process_t* init = proc_load("/programs/init", (struct console*)current_console, 0, "/");
 	if (!init) {
 		preboot_fail("/programs/init missing or invalid!\n");
 	}

src/tokenizer.c

@@ -31,6 +31,7 @@ const int keywords[] = {
 	BACKGROUND,
 	CALL,
 	CHAIN,
+	CHDIR,
 	CIRCLE,
 	CLOSE,
 	CLS,

src/ubasic.c

@@ -83,6 +83,7 @@ struct ubasic_str_fn builtin_str[] =
 	{ ubasic_upper, "UPPER$" },
 	{ ubasic_lower, "LOWER$" },
 	{ ubasic_tokenize, "TOKENIZE$" },
+	{ ubasic_csd, "CSD$" },
 	{ NULL, NULL }
 };
 
@@ -865,7 +866,7 @@ void chain_statement(struct ubasic_ctx* ctx)
 {
 	accept(CHAIN, ctx);
 	const char* pn = str_expr(ctx);
-	process_t* p = proc_load(pn, ctx->cons, proc_cur()->pid);
+	process_t* p = proc_load(pn, ctx->cons, proc_cur()->pid, proc_cur()->csd);
 	if (p == NULL) {
 		accept(NEWLINE, ctx);
 		return;
@@ -1585,6 +1586,8 @@ void statement(struct ubasic_ctx* ctx)
 			return push_statement(ctx);
 		case POP:
 			return pop_statement(ctx);
+		case CHDIR:
+			return chdir_statement(ctx);
 		case CIRCLE:
 			return circle_statement(ctx);
 		case LET:
@@ -1605,6 +1608,29 @@ void statement(struct ubasic_ctx* ctx)
 	}
 }
 
+void chdir_statement(struct ubasic_ctx* ctx)
+{
+	accept(CHDIR, ctx);
+	const char* csd = str_expr(ctx);
+	accept(NEWLINE, ctx);
+	const char* old = strdup(proc_cur()->csd);
+	const char* new = proc_set_csd(proc_cur(), csd);
+	if (new && fs_is_directory(new)) {
+		kfree(old);
+		return;
+	}
+
+	if (!new) {
+		tokenizer_error_print(ctx, "Invalid directory");
+	}
+	if (!fs_is_directory(new)) {
+		tokenizer_error_print(ctx, "Not a directory");
+	}
+
+	proc_set_csd(proc_cur(), old);
+	kfree(old);
+}
+
 void line_statement(struct ubasic_ctx* ctx)
 {
 	ctx->current_linenum = tokenizer_num(ctx, NUMBER);
@@ -2265,6 +2291,11 @@ char* ubasic_lower(struct ubasic_ctx* ctx)
 	return modified;
 }
 
+char* ubasic_csd(struct ubasic_ctx* ctx)
+{
+	return gc_strdup(proc_cur()->csd);
+}
+
 char* ubasic_tokenize(struct ubasic_ctx* ctx)
 {
 	char* varname, *split;