shell can launch another user processgit add .git add .!

build_programs.sh

@@ -20,4 +20,10 @@ bear -- make
 cp vga_text_term.elf ../bin
 cd ..
 
+cd test
+make clean
+bear -- make 
+cp test.elf ../bin
+cd ..
+
 cd ..

compile_commands.json

@@ -26,12 +26,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/vfs.c.o",
+      "obj/kernel/kbd.c.o",
-      "kernel/vfs.c"
+      "kernel/kbd.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/vfs.c",
+    "file": "/home/slinky/source/RockOS/kernel/kbd.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/vfs.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/kbd.c.o"
   },
   {
     "arguments": [
@@ -43,12 +43,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/kmain.c.o",
+      "obj/kernel/gdt.c.o",
-      "kernel/kmain.c"
+      "kernel/gdt.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/kmain.c",
+    "file": "/home/slinky/source/RockOS/kernel/gdt.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/kmain.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.c.o"
   },
   {
     "arguments": [
@@ -67,91 +67,6 @@
     "file": "/home/slinky/source/RockOS/kernel/drivers/pic/pic.c",
     "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pic/pic.c.o"
   },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/devfs/devfs.c.o",
-      "kernel/drivers/devfs/devfs.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/devfs/devfs.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/devfs/devfs.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/cpio/cpio.c.o",
-      "kernel/drivers/cpio/cpio.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/cpio/cpio.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/cpio/cpio.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/pty/pty.c.o",
-      "kernel/drivers/pty/pty.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/pty/pty.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pty/pty.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/vga/vga.c.o",
-      "kernel/drivers/vga/vga.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/vga/vga.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/vga/vga.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/ide/ide.c.o",
-      "kernel/drivers/ide/ide.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/ide/ide.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/ide/ide.c.o"
-  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -196,12 +111,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/gdt.c.o",
+      "obj/kernel/drivers/ide/ide.c.o",
-      "kernel/gdt.c"
+      "kernel/drivers/ide/ide.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/gdt.c",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/ide/ide.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/ide/ide.c.o"
   },
   {
     "arguments": [
@@ -213,12 +128,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/memory/mm.c.o",
+      "obj/kernel/drivers/vga/vga.c.o",
-      "kernel/memory/mm.c"
+      "kernel/drivers/vga/vga.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/memory/mm.c",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/vga/vga.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/vga/vga.c.o"
   },
   {
     "arguments": [
@@ -230,12 +145,80 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/kbd.c.o",
+      "obj/kernel/drivers/cpio/cpio.c.o",
-      "kernel/kbd.c"
+      "kernel/drivers/cpio/cpio.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/kbd.c",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/cpio/cpio.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/kbd.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/cpio/cpio.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/drivers/devfs/devfs.c.o",
+      "kernel/drivers/devfs/devfs.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/devfs/devfs.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/devfs/devfs.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/drivers/pty/pty.c.o",
+      "kernel/drivers/pty/pty.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/pty/pty.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pty/pty.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/scheduler.c.o",
+      "kernel/scheduler.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/scheduler.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/scheduler.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/elf.c.o",
+      "kernel/elf.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/elf.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/elf.c.o"
   },
   {
     "arguments": [
@@ -271,23 +254,6 @@
     "file": "/home/slinky/source/RockOS/kernel/interrupts.c",
     "output": "/home/slinky/source/RockOS/obj/kernel/interrupts.c.o"
   },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/elf.c.o",
-      "kernel/elf.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/elf.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/elf.c.o"
-  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -315,63 +281,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/lib/stream.c.o",
+      "obj/kernel/kmain.c.o",
-      "kernel/lib/stream.c"
+      "kernel/kmain.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/stream.c",
+    "file": "/home/slinky/source/RockOS/kernel/kmain.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/stream.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/kmain.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/lib/memory.c.o",
-      "kernel/lib/memory.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/memory.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/memory.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/lib/print.c.o",
-      "kernel/lib/print.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/print.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/print.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/lib/ringbuf.c.o",
-      "kernel/lib/ringbuf.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/ringbuf.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/ringbuf.c.o"
   },
   {
     "arguments": [
@@ -390,6 +305,40 @@
     "file": "/home/slinky/source/RockOS/kernel/lib/tasks.c",
     "output": "/home/slinky/source/RockOS/obj/kernel/lib/tasks.c.o"
   },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/lib/ringbuf.c.o",
+      "kernel/lib/ringbuf.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/lib/ringbuf.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/ringbuf.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/lib/stream.c.o",
+      "kernel/lib/stream.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/lib/stream.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/stream.c.o"
+  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -417,12 +366,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/scheduler.c.o",
+      "obj/kernel/lib/print.c.o",
-      "kernel/scheduler.c"
+      "kernel/lib/print.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/scheduler.c",
+    "file": "/home/slinky/source/RockOS/kernel/lib/print.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/scheduler.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/print.c.o"
   },
   {
     "arguments": [
@@ -434,12 +383,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/syscall.S.o",
+      "obj/kernel/lib/memory.c.o",
-      "kernel/syscall.S"
+      "kernel/lib/memory.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/syscall.S",
+    "file": "/home/slinky/source/RockOS/kernel/lib/memory.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/syscall.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/memory.c.o"
   },
   {
     "arguments": [
@@ -451,12 +400,29 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/common.S.o",
+      "obj/kernel/vfs.c.o",
-      "kernel/common.S"
+      "kernel/vfs.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/common.S",
+    "file": "/home/slinky/source/RockOS/kernel/vfs.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/common.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/vfs.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/memory/mm.c.o",
+      "kernel/memory/mm.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/memory/mm.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.c.o"
   },
   {
     "arguments": [
@@ -475,23 +441,6 @@
     "file": "/home/slinky/source/RockOS/kernel/drivers/pic/pic.S",
     "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pic/pic.S.o"
   },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/pit/pit.S.o",
-      "kernel/drivers/pit/pit.S"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/pit/pit.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pit/pit.S.o"
-  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -519,12 +468,46 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/memory/mm.S.o",
+      "obj/kernel/drivers/pit/pit.S.o",
-      "kernel/memory/mm.S"
+      "kernel/drivers/pit/pit.S"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/memory/mm.S",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/pit/pit.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pit/pit.S.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/syscall.S.o",
+      "kernel/syscall.S"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/syscall.S",
+    "output": "/home/slinky/source/RockOS/obj/kernel/syscall.S.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/interrupts.S.o",
+      "kernel/interrupts.S"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/interrupts.S",
+    "output": "/home/slinky/source/RockOS/obj/kernel/interrupts.S.o"
   },
   {
     "arguments": [
@@ -543,6 +526,23 @@
     "file": "/home/slinky/source/RockOS/kernel/boot/boot.S",
     "output": "/home/slinky/source/RockOS/obj/kernel/boot/boot.S.o"
   },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/common.S.o",
+      "kernel/common.S"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/common.S",
+    "output": "/home/slinky/source/RockOS/obj/kernel/common.S.o"
+  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -570,12 +570,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/gdt.S.o",
+      "obj/kernel/memory/mm.S.o",
-      "kernel/gdt.S"
+      "kernel/memory/mm.S"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/gdt.S",
+    "file": "/home/slinky/source/RockOS/kernel/memory/mm.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.S.o"
   },
   {
     "arguments": [
@@ -587,11 +587,11 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/interrupts.S.o",
+      "obj/kernel/gdt.S.o",
-      "kernel/interrupts.S"
+      "kernel/gdt.S"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/interrupts.S",
+    "file": "/home/slinky/source/RockOS/kernel/gdt.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/interrupts.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.S.o"
   }
 ]

kernel/process.h

@@ -12,6 +12,7 @@ typedef enum {
     STATE_SLEEPING = 2,
     STATE_BLOCKED = 3,
     STATE_DEAD = 4,
+    STATE_ZOMBIE = 5,
 } process_state_t;
 
 typedef enum {
@@ -32,6 +33,8 @@ typedef struct process_t {
     uint32_t flags;
     file_t* fd_table[MAX_PROCESS_FDS];
     struct process_t* sched_next;
+    struct process_t* waiting;
+    int exit_status;
 } __attribute__((packed)) process_t;
 
 #endif 

kernel/scheduler.c

@@ -186,4 +186,13 @@ void wake(process_t* task) {
     if (task->state == STATE_SLEEPING || task->state == STATE_BLOCKED) {
         task->state = STATE_READY;
     }
+}
+
+process_t* get_task_by_pid(uint32_t pid) {
+    process_t* cur = process_table;
+    while (cur) {
+        if (cur->pid == pid) break;
+        cur = cur->sched_next;
+    }
+    return cur;
 }

kernel/scheduler.h

@@ -11,6 +11,7 @@ void init_scheduler();
 void init_task(process_t* process, uint32_t entry_point, uint32_t cr3, int user, uint32_t u_esp);
 
 process_t* current_task();
+process_t* get_task_by_pid(uint32_t pid);
 
 int get_next_pid();
 void add_task(process_t* task);

kernel/syscall.c

@@ -25,7 +25,11 @@ typedef struct registers {
 
 static int32_t sys_exit(int status) {
     process_t* task = current_task();
-    task->state = STATE_DEAD;
+    task->state = STATE_ZOMBIE;
+    task->exit_status = status;
+    if (task->waiting) {
+        wake(task->waiting);
+    }
     exit();
     return 0;
 }
@@ -163,6 +167,9 @@ static int32_t sys_exec(registers_t* regs, const char* prgm) {
     clear_current_pd();
 
     uint32_t eip = load_elf_program(prgm);
+    if (eip == 0) {
+        return 0;
+    }
 
     uint32_t stack_sz = PAGE_SIZE * 16;
     uint32_t stack_top = 0xBFFF0000;
@@ -204,6 +211,16 @@ static int32_t sys_lseek(int fd, size_t offset, int whence) {
     return 1;
 }
 
+static int32_t sys_waitpid(int pid, int* exit_status) {
+    process_t* current = current_task();
+    process_t* child = get_task_by_pid(pid);
+    current->state = STATE_BLOCKED;
+    child->waiting = current;
+    yield();
+    *exit_status = child->exit_status;
+    return 1;
+}
+
 void syscall(registers_t* regs) {
     int32_t ret;
     switch(regs->eax) {
@@ -218,6 +235,7 @@ void syscall(registers_t* regs) {
         case 22: ret = sys_exec(regs, (const char*)regs->ebx); break;
         case 23: ret = sys_dup2(regs->ebx, regs->ecx); break;
         case 24: ret = sys_lseek(regs->ebx, regs->ecx, regs->edx); break;
+        case 25: ret = sys_waitpid(regs->ebx, (int*)regs->ecx); break;
         default: ret = -1;
     }
     regs->eax = ret;

programs/rocksh/main.c

@@ -1,3 +1,4 @@
+#include "syscall.h"
 #include <unistd.h>
 #include <stdio.h>
 #include <string.h>
@@ -7,6 +8,10 @@ const char* shell_prompt = "rocksh> ";
 char buf[256];
 size_t buf_offset = 0;
 
+char path[256];
+
+const char* bin_dir = "/bin/";
+
 void parse_cmd() {
     if (strcmp(buf, "exit") == 0) {
         printf("bye!\n");
@@ -15,7 +20,25 @@ void parse_cmd() {
 
     if (strcmp(buf, "motd")  == 0) {
         printf("rockos is the best!\n");
+        return;
     }
+
+    // need a strcat
+    char* dst = path;
+    strcpy(dst, bin_dir);
+    dst = path + strlen(bin_dir);
+    strcpy(dst, buf);
+
+    int pid = fork();
+    if (pid == 0) {
+        if (!exec(path)) {
+            return;
+        }
+    }
+
+    int status;
+    waitpid(pid, &status);
+    printf("process exited with status %d\n", status);
 }
 
 void reset() {

programs/test/compile_commands.json

@@ -0,0 +1,36 @@
+[
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-I../../rocklibc/include",
+      "-c",
+      "-o",
+      "crt0.o",
+      "crt0.S"
+    ],
+    "directory": "/home/slinky/source/RockOS/programs/test",
+    "file": "/home/slinky/source/RockOS/programs/test/crt0.S",
+    "output": "/home/slinky/source/RockOS/programs/test/crt0.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-I../../rocklibc/include",
+      "-c",
+      "-o",
+      "main.o",
+      "main.c"
+    ],
+    "directory": "/home/slinky/source/RockOS/programs/test",
+    "file": "/home/slinky/source/RockOS/programs/test/main.c",
+    "output": "/home/slinky/source/RockOS/programs/test/main.o"
+  }
+]

programs/test/crt0.S

@@ -0,0 +1,21 @@
+.global _start
+.extern exit
+.section .text
+_start: 
+    xor %ebp, %ebp
+
+    mov (%esp), %eax
+    lea 4(%esp), %ebx
+    lea 8(%esp,%eax,4), %ecx
+
+    and $-16, %esp
+
+    push %ecx
+    push %ebx
+    push %eax
+
+    call main
+
+    push %eax
+    call exit
+

programs/test/linker.ld

@@ -0,0 +1,31 @@
+ENTRY(_start)
+
+SECTIONS
+{
+    . = 0x40000000;
+
+    .text ALIGN(4K) :
+    {
+        /* Force the crt0.o entry code to be placed FIRST in memory */
+        KEEP(*crt0.o(.text))
+        *(.text .text.*)
+    }
+
+    .rodata ALIGN(4K) :
+    {
+        *(.rodata .rodata.*)
+    }
+
+    .data ALIGN(4K) :
+    {
+        *(.data .data.*)
+    }
+
+    .bss ALIGN(4K) :
+    {
+        _bss_start = .;
+        *(.bss .bss.*)
+        *(COMMON)
+        _bss_end = .;
+    }
+}

programs/test/main.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main(int argc, char** argv) {
+    printf("hello, world!\n");
+    return 0;
+}

programs/test/makefile

@@ -0,0 +1,23 @@
+CC = i686-elf-gcc
+LD = i686-elf-ld
+
+CFLAGS = -ffreestanding -O2 -Wall -Wextra -I../../rocklibc/include
+LDFLAGS = -m elf_i386 -nostdlib
+
+TARGET = test.elf
+
+all: $(TARGET)
+
+crt0.o: crt0.S
+	$(CC) $(CFLAGS) -c crt0.S -o crt0.o
+
+main.o: main.c
+	$(CC) $(CFLAGS) -c main.c -o main.o
+
+$(TARGET): crt0.o main.o ../lib/rlibc.a
+	$(LD) $(LDFLAGS) -T linker.ld crt0.o main.o ../lib/rlibc.a -o $(TARGET)
+
+clean:
+	rm -f *.o $(TARGET)
+
+.PHONY: all clean test

rocklibc/include/syscall.h

@@ -13,7 +13,8 @@
 #define SYS_FORK    21
 #define SYS_EXEC    22
 #define SYS_DUP2    23
-#define SYS_LSEEK    24
+#define SYS_LSEEK   24
+#define SYS_WAIT    25
 
 int open(const char* path);
 int write(int fd, const void *buf, size_t count);
@@ -32,5 +33,6 @@ int pty(int* slave);
 int fork();
 int exec(const char* path);
 int dup2(int src, int dst);
+int waitpid(int pid, int* status);
 
 #endif

rocklibc/src/syscall.c

@@ -61,4 +61,8 @@ int exec(const char* path) {
 
 int dup2(int src, int dst) {
     return syscall3(SYS_DUP2, src, dst, 0);
+}
+
+int waitpid(int pid, int* status) {
+    return syscall3(SYS_WAIT, pid, (uint32_t)status, 0);
 }