kernel: proc: Handle parent exit

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 37 insertions, 4 deletions

diff --git a/sys/include/sys/proc.h b/sys/include/sys/proc.h
index d252ab7..4024879 100644
--- a/sys/include/sys/proc.h
+++ b/sys/include/sys/proc.h
@@ -63,21 +63,31 @@ struct proc {
     struct spinlock vcache_lock;
     struct trapframe tf;
     struct pcb pcb;
+    struct proc *parent;
     size_t priority;
+    int exit_status;
     bool rested;
     uint32_t flags;
+    uint32_t nleaves;
     uintptr_t stack_base;
     struct spinlock ksigq_lock;
+    TAILQ_HEAD(, proc) leafq;
+    TAILQ_ENTRY(proc) leaf_link;
     TAILQ_HEAD(, ksiginfo) ksigq;
     TAILQ_ENTRY(proc) link;
 };
 
 #define PROC_EXITING    BIT(0)  /* Exiting */
 #define PROC_EXEC       BIT(1)  /* Exec called (cleared by sched) */
+#define PROC_ZOMB       BIT(2)  /* Zombie (dead but not deallocated) */
+#define PROC_LEAFQ      BIT(3)  /* Leaf queue is active */
+#define PROC_WAITED     BIT(4)  /* Being waited on by parent */
 
 struct proc *this_td(void);
 int md_spawn(struct proc *p, struct proc *parent, uintptr_t ip);
-int spawn(struct proc *cur, int flags, void(*ip)(void), struct proc **newprocp);
+
+scret_t sys_spawn(struct syscall_args *scargs);
+pid_t spawn(struct proc *cur, void(*func)(void), void *p, int flags, struct proc **newprocp);
 
 void md_td_stackinit(struct proc *td, void *stack_top, struct exec_prog *prog);
 __dead void md_td_kick(struct proc *td);
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 75ab0e9..24c7e74 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -81,7 +81,7 @@ int
 exit1(struct proc *td)
 {
     struct pcb *pcbp;
-    struct proc *curtd;
+    struct proc *curtd, *procp;
     uintptr_t stack;
     pid_t target_pid, curpid;
 
@@ -93,6 +93,13 @@ exit1(struct proc *td)
     stack = td->stack_base;
     td->flags |= PROC_EXITING;
 
+    /* If we have any children, kill them too */
+    if (td->nleaves > 0) {
+        TAILQ_FOREACH(procp, &td->leafq, leaf_link) {
+            exit1(procp);
+        }
+    }
+
     /*
      * If this is on the higher half, it is kernel
      * mapped and we need to convert it to a physical
@@ -107,7 +114,17 @@ exit1(struct proc *td)
     vm_free_frame(stack, PROC_STACK_PAGES);
 
     pmap_destroy_vas(pcbp->addrsp);
-    dynfree(td);
+
+    /*
+     * Only free the process structure if we aren't
+     * being waited on, otherwise let it be so the
+     * parent can examine what's left of it.
+     */
+    if (!ISSET(td->flags, PROC_WAITED)) {
+        dynfree(td);
+    } else {
+        td->flags |= PROC_ZOMB;
+    }
 
     /*
      * If we are the thread exiting, reenter the scheduler
@@ -119,9 +136,15 @@ exit1(struct proc *td)
     return 0;
 }
 
+/*
+ * arg0: Exit status.
+ */
 scret_t
 sys_exit(struct syscall_args *scargs)
 {
-    exit1(this_td());
+    struct proc *td = this_td();
+
+    td->exit_status = scargs->arg0;
+    exit1(td);
     __builtin_unreachable();
 }