Implement process clone trampoline

ce/interp.c

@@ -289,8 +289,8 @@ static void help (struct context* context) {
   cprintf (context, "quit\n");
 }
 
-static void cmd_cancel_proc (void) {
+static void cmd_cancel_proc (void* arg) {
-  int pid = *(int*)argument_ptr ();
+  int pid = *(int*)arg;
 
   char ch = 0;
   for (;;) {
@@ -301,8 +301,6 @@ static void cmd_cancel_proc (void) {
   }
 
   kill (pid);
-
-  quit ();
 }
 
 static void execute_cmd (struct ast_cmd* cmd, struct context* context) {
@@ -342,11 +340,12 @@ static void execute_cmd (struct ast_cmd* cmd, struct context* context) {
       return;
     }
 
-    int cancel_pid = process_spawn (&cmd_cancel_proc, &pid);
+    struct process_data* cancel_pdata = process_spawn (&cmd_cancel_proc, &pid);
 
     wait_for_pid (pid);
 
-    kill (cancel_pid);
+    if (kill (cancel_pdata->pid) < 0)
+      free (cancel_pdata);
   }
 }
 

init/init.c

@@ -10,7 +10,9 @@
 
 static int ce_pgid;
 
-void receiver (void) {
+void receiver (void* arg) {
+  (void)arg;
+
   for (;;) {
     char recv[RECV_MAX];
     memset (recv, 0, sizeof (recv));

libprocess/amd64/.gitignore

@@ -0,0 +1 @@
+*.o

libprocess/amd64/clone_tramp.S

@@ -0,0 +1,7 @@
+.global _clone_tramp
+_clone_tramp:
+  xorq %rbp, %rbp
+  movq %rsp, %rbp
+  andq $-16, %rsp
+
+  callq _clone_tramp1

libprocess/amd64/clone_tramp1.c

@@ -0,0 +1,12 @@
+#include <liballoc.h>
+#include <process.h>
+#include <system.h>
+
+void _clone_tramp1 (void) {
+  struct process_data* pdata = argument_ptr ();
+
+  pdata->fn (pdata->arg_ptr);
+
+  free (pdata);
+  quit ();
+}

libprocess/amd64/src.mk

@@ -0,0 +1,6 @@
+c += amd64/clone_tramp1.c
+
+S += amd64/clone_tramp.S
+
+o += amd64/clone_tramp.o \
+		 amd64/clone_tramp1.o

libprocess/process.c

@@ -7,11 +7,32 @@
 #include <stdint.h>
 #include <system.h>
 
-int process_spawn (process_func_t func, void* argument_ptr) {
+void _clone_tramp (void);
+
+struct process_data* process_spawn (process_func_t func, void* argument_ptr) {
   void* stack = malloc (STACK_SIZE);
   if (stack == NULL)
-    return -ST_OOM_ERROR;
+    return NULL;
+
+  struct process_data* pdata = malloc (sizeof (*pdata));
+
+  if (pdata == NULL) {
+    free (stack);
+    return NULL;
+  }
+
+  pdata->arg_ptr = argument_ptr;
+  pdata->fn = func;
 
   uintptr_t top = (uintptr_t)stack + STACK_SIZE;
-  return clone (top, func, argument_ptr);
+  int pid = clone (top, &_clone_tramp, (void*)pdata);
+
+  if (pid < 0) {
+    free (stack);
+    free (pdata);
+    return NULL;
+  }
+
+  pdata->pid = pid;
+  return pdata;
 }

libprocess/process.h

@@ -8,9 +8,15 @@
 #define STACK_SIZE (256 * PAGE_SIZE)
 
 /* Process entry function */
-typedef void (*process_func_t) (void);
+typedef void (*process_func_t) (void*);
+
+struct process_data {
+  void* arg_ptr;
+  process_func_t fn;
+  int pid;
+};
 
 /* Spawn a new process within the same procgroup with argument */
-int process_spawn (process_func_t func, void* argument_ptr);
+struct process_data* process_spawn (process_func_t func, void* argument_ptr);
 
 #endif // _LIBPROCESS_PROCESS_PROCESS_H

libprocess/src.mk

@@ -1,3 +1,5 @@
+include $(platform)/src.mk
+
 c += process.c
 
 o += process.o