have command shell block while commands are running

doc/ints.txt

@@ -15,7 +15,6 @@ see table 1
 
 file system calls have units of bytes unless otherwise specified
 functions returning handles or pointers use 0 to indicate error
-functions returning "success" use 1 for success and 0 for failure
 see keys.txt for the return type of the "get key" system call
 the edx register of "start task" is a pointer to a null-terminated string.
   a pointer to a readonly copy of this string is put into the new task's edx.
@@ -31,11 +30,14 @@ table 1:
  close file    | 0x1 |               | handle        |             |           |        |
  file read     | 0x2 | read          | handle        | file offset | count     | buffer |
  get file size | 0x3 | size          | handle        |             |           |        |
- start task    | 0x4 | success       | drive number  | path        | passed sz |        |
+ start task    | 0x4 | handle        | drive number  | path        | passed sz |        |
  log string    | 0x5 |               | sz string     |             |           |        |
  get key       | 0x6 | keycode       |               |             |           |        |
  allocate ram  | 0x7 | start pointer | pages         |             |           |        |
  memory info   | 0x8 | see table 2   | see table 2   |             |           |        |
+ wait for task | 0x9 |               | handle        |             |           |        |
+
+
 
 
 table 2:

src/kernel/elf.c

@@ -73,10 +73,10 @@ struct ph_entry {
   uint32_t align;
 } __attribute__ ((packed));
 
-bool try_elf_run(const struct drive *d, const char *path, const char *pass_old_vma) {
+uint32_t try_elf_run(const struct drive *d, const char *path, const char *pass_old_vma) {
   file_id_t h = d->get_file(d, path);
   if (!h)
-    return false;
+    return 0;
 
   struct elf_header ehead;
 
@@ -87,7 +87,7 @@ bool try_elf_run(const struct drive *d, const char *path, const char *pass_old_v
       (ehead.endianness != LITTLE_ENDIAN) ||
        ehead.os_abi_version) {
     d->free_file(d, h);
-    return false;
+    return 0;
   }
 
   uint32_t phtable_size = ehead.phentry_size * ehead.phtable_count;
@@ -104,7 +104,7 @@ bool try_elf_run(const struct drive *d, const char *path, const char *pass_old_v
       continue;
     void *pma = pd_user_allocate(pd, entry->vma, (entry->vms - 1) / 4096 + 1, entry->flags & PH_WRITABLE);
     fmcpy(pma, d, h, entry->fa, entry->fs);
-    for (uint8_t *pma_i = pma + entry->fs; pma_i < pma + entry->vms; ++pma_i)
+    for (uint8_t *pma_i = pma + entry->fs; pma_i < (uint8_t *)pma + entry->vms; ++pma_i)
       *pma_i = 0;
   }
 
@@ -128,6 +128,7 @@ bool try_elf_run(const struct drive *d, const char *path, const char *pass_old_v
   tstate.page_directory = pd;
   tstate.ret_addr = ehead.entry_vma;
   tstate.edx = (uint32_t)pass_vma;
+  tstate.wait_mode = NONE;
 
   const char *path_end_start = path;
   for (const char *i = path; *i; ++i)
@@ -142,6 +143,5 @@ bool try_elf_run(const struct drive *d, const char *path, const char *pass_old_v
   }
   tstate.name[i] = '\0';
 
-  new_task(tstate);
-  return true;
+  return new_task(tstate);
 }

src/kernel/elf.h

@@ -4,6 +4,6 @@
 #include <stdint.h>
 #include "drive.h"
 
-bool try_elf_run(const struct drive *d, const char *path, const char *pass_old_vma);
+uint32_t try_elf_run(const struct drive *d, const char *path, const char *pass_old_vma);
 
 #endif

src/kernel/idt.c

@@ -54,11 +54,11 @@ static uint32_t sc_file_read(uint32_t handle, uint32_t file_offset, uint32_t cou
   return count;
 }
 
-static bool sc_start_task(uint32_t drive_number, char *path, const char *pass) {
+static uint32_t sc_start_task(uint32_t drive_number, char *path, const char *pass) {
   switch_to_kernel_cr3();
-  bool result = try_elf_run(drives + drive_number, vma_to_pma(active_task->page_directory, path), pass);
+  uint32_t process_id = try_elf_run(drives + drive_number, vma_to_pma(active_task->page_directory, path), pass);
   switch_to_task_cr3();
-  return result;
+  return process_id;
 }
 
 static void *sc_allocate_ram(uint32_t pages) {
@@ -91,6 +91,11 @@ static uint32_t sc_memory_info(enum mi_arg arg) {
   }
 }
 
+static void sc_wait_for_task(uint32_t handle) {
+  active_task->wait_mode = PROCESS_END;
+  active_task->wait_arg = handle;
+}
+
 void const *syscall_table[] = {
   &sc_open_file,
   &sc_close_file,
@@ -100,7 +105,8 @@ void const *syscall_table[] = {
   &logsz,
   &get_key_code,
   &sc_allocate_ram,
-  &sc_memory_info
+  &sc_memory_info,
+  &sc_wait_for_task
 };
 
 //these aren't really void ()'s, but gcc complains if we take an address of a void, so we give it a type

src/kernel/isrs.asm

@@ -23,7 +23,7 @@ extern on_kbd_isr
 extern make_sure_tasks
 extern exception_halt
 
-n_syscalls equ 0x9
+n_syscalls equ 0xa
 
 ;section .bss
 ;_debug_is_start_task resb 1

src/kernel/kbd.c

@@ -1,7 +1,5 @@
 #include <stdint.h>
-#include <stdbool.h>
 #include "panic.h"
-#include "log.h"
 #include "util.h"
 
 static uint32_t *kbd_in_pointer;

src/kernel/task.c

@@ -64,11 +64,11 @@ void init_tasks() {
   : : : "ax");
 }
 
-void new_task(struct task_state state) {
+uint32_t new_task(struct task_state state) {
   for (uint8_t n = 0; n < MAX_TASKS; ++n)
     if (!tasks[n].page_directory) {
       tasks[n] = state;
-      return;
+      return n + 1;
     }
   PANIC("Maximum number of tasks reached.");
 }
@@ -77,15 +77,20 @@ void advance_active_task() {
   do
     if (++active_task == tasks + MAX_TASKS)
       active_task = tasks;
-  while (!active_task->page_directory);
+  while (!active_task->page_directory || active_task->wait_mode);
 }
 
 void make_sure_tasks() {
   for (uint8_t n = 0; n < MAX_TASKS; ++n)
     if (tasks[n].page_directory)
+      while (1) {
+        for (uint8_t n = 0; n < MAX_TASKS; ++n)
+          if (tasks[n].page_directory && !tasks[n].wait_mode)
             return;
+        asm ("hlt");
+      }
   set_log_mode(LOG_SYSTEM);
-  logsz("No active tasks, halting.");
+  logsz("No tasks, halting.");
   while (1)
     asm ("hlt");
 }
@@ -95,4 +100,11 @@ void delete_task(struct task_state *state) {
   free_task_pd(state->page_directory);
   switch_to_task_cr3();
   state->page_directory = 0;
+
+  uint32_t handle = state - tasks + 1;
+  for (uint8_t n = 0; n < MAX_TASKS; ++n)
+    if (tasks[n].page_directory &&
+       (tasks[n].wait_mode == PROCESS_END) &&
+       (tasks[n].wait_arg == handle))
+      tasks[n].wait_mode = NONE;
 }

src/kernel/task.h

@@ -6,6 +6,11 @@
 
 #define TASK_NAME_LEN 15
 
+enum wait_mode {
+  NONE,
+  PROCESS_END,
+};
+
 struct task_state {
   uint32_t ret_addr;
   void *page_directory;
@@ -18,6 +23,9 @@ struct task_state {
   uint32_t ebp;
   uint32_t esp;
 
+  enum wait_mode wait_mode;
+  uint32_t wait_arg;
+
   char name[TASK_NAME_LEN + 1];
 } __attribute__ ((packed));
 
@@ -25,7 +33,7 @@ extern struct task_state *active_task;
 
 void init_tasks();
 
-void new_task(struct task_state state);
+uint32_t new_task(struct task_state state);
 void advance_active_task();
 
 void delete_task(struct task_state *state);

src/user/highway/highway.c

@@ -18,9 +18,7 @@ void main() {
     ask_user_line_sz(line_buf, 1023);
     if (blockequ(line_buf, "exit", 5))
       return;
-    if (try_run_command(path_buf))
-      yield_task();
-    else
+    if (!try_run_command_blocking(path_buf))
       tell_user_sz("An error occured trying to run that command.\n");
   }
 }

src/user/include/knob/task.h

@@ -1,9 +1,11 @@
 #ifndef KNOB_TASK_H
 #define KNOB_TASK_H
 
+#include <stdint.h>
 #include <stdbool.h>
 
-bool try_run_command(const char *path);
+uint32_t run_command(const char *path);
+bool try_run_command_blocking(const char *path);
 void yield_task();
 
 #endif

src/user/include/pland/syscall.h

@@ -8,6 +8,7 @@ typedef uint32_t _file_handle_t;
 typedef uint32_t _task_handle_t;
 typedef uint32_t _drive_number_t;
 typedef uint32_t _pages_t;
+typedef uint32_t _process_handle_t;
 
 typedef enum {
   _KEY_BACKSPACE = '\b',
@@ -43,7 +44,8 @@ enum _scn {
   _SCN_LOG_STRING,
   _SCN_GET_KEY,
   _SCN_ALLOCATE_RAM,
-  _SCN_MEMORY_INFO
+  _SCN_MEMORY_INFO,
+  _SCN_WAIT_FOR_TASK
 };
 
 static inline uint32_t _sc0(enum _scn eax) {
@@ -124,8 +126,8 @@ static inline uint32_t _file_size(_file_handle_t handle) {
   return _sc1(_SCN_FILE_SIZE, handle);
 }
 
-static inline bool _start_task(_drive_number_t drive_number, const char *path, const char *pass) {
-  return (bool)_sc3(_SCN_START_TASK, drive_number, (uint32_t)path, (uint32_t)pass);
+static inline _process_handle_t _start_task(_drive_number_t drive_number, const char *path, const char *pass) {
+  return _sc3(_SCN_START_TASK, drive_number, (uint32_t)path, (uint32_t)pass);
 }
 
 static inline void _log_string(const char *sz) {
@@ -160,4 +162,8 @@ static inline _pages_t _this_process_memory_left() {
   return _sc1(_SCN_MEMORY_INFO, 0x4);
 }
 
+static inline void _wait_for_task(_process_handle_t handle) {
+  _sc1(_SCN_WAIT_FOR_TASK, handle);
+}
+
 #endif

src/user/init/init.c

@@ -7,7 +7,7 @@ void start(const char *cmd) {
   tell_user_sz(cmd);
   tell_user_sz(": ");
   tell_user_sz(
-    try_run_command(cmd)
+    run_command(cmd)
       ? "Succeded.\n"
       : "Failed.\n"
   );

src/user/knob/task.c

@@ -4,7 +4,7 @@
 #include <knob/heap.h>
 #include <knob/block.h>
 
-bool try_run_command(const char *path) {
+_task_handle_t run_command(const char *path) {
   uint8_t dn;
   path = remove_prefix(path, &dn);
 
@@ -22,6 +22,15 @@ bool try_run_command(const char *path) {
   return _start_task(dn, path, "");
 }
 
+bool try_run_command_blocking(const char *path) {
+  _task_handle_t handle = run_command(path);
+  if (!handle)
+    return false;
+  _wait_for_task(handle);
+  _yield_task();
+  return true;
+}
+
 void yield_task() {
   _yield_task();
 }