7 files changed, 44 insertions, 20 deletions

diff --git a/src/kernel/elf.c b/src/kernel/elf.c
index 8113c14..60fa3a9 100644
--- a/src/kernel/elf.c
+++ b/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);
 }
\ No newline at end of file
diff --git a/src/kernel/elf.h b/src/kernel/elf.h
index 98489f2..89726c9 100644
--- a/src/kernel/elf.h
+++ b/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
\ No newline at end of file
diff --git a/src/kernel/idt.c b/src/kernel/idt.c
index b789d42..4ffa1e2 100644
--- a/src/kernel/idt.c
+++ b/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
diff --git a/src/kernel/isrs.asm b/src/kernel/isrs.asm
index 4f2d4e2..8a27d57 100644
--- a/src/kernel/isrs.asm
+++ b/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
diff --git a/src/kernel/kbd.c b/src/kernel/kbd.c
index 73a5ec6..f3eb323 100644
--- a/src/kernel/kbd.c
+++ b/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;
diff --git a/src/kernel/task.c b/src/kernel/task.c
index 6c53510..942d1c4 100644
--- a/src/kernel/task.c
+++ b/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)
-      return;
+      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;
 }
\ No newline at end of file
diff --git a/src/kernel/task.h b/src/kernel/task.h
index 0fa9688..50be93a 100644
--- a/src/kernel/task.h
+++ b/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);