Implement UM#waitpid

Author: noteflakes

CHANGELOG.md

@@ -1,4 +1,5 @@
-- Add `#pipe`
+- Add `#waitpid`
+- Add `UM.pipe`, `UM.kernel_version`
 - Add `#open`
 - Fix `#spin`
 - Fix handling of signal interruption.

TODO.md

@@ -7,7 +7,6 @@
 - statx
 - link / linkat / unlink / unlinkat / symlink
 - rename / renameat
-- waitid
 - fadvise
 - madvise
 - getxattr / setxattr

ext/um/um.c

@@ -513,6 +513,24 @@ VALUE um_open(struct um *machine, VALUE pathname, int flags, int mode) {
   return raise_if_exception(ret);
 }
 
+VALUE um_waitpid(struct um *machine, int pid, int options) {
+  struct um_op op;
+  um_prep_op(machine, &op, OP_BIND);
+  struct io_uring_sqe *sqe = um_get_sqe(machine, &op);
+
+  siginfo_t infop;
+  io_uring_prep_waitid(sqe, P_PID, pid, &infop, options, 0);
+
+  VALUE ret = um_fiber_switch(machine);
+  if (um_check_completion(machine, &op))
+    ret = INT2NUM(op.result.res);
+
+  RB_GC_GUARD(ret);
+  raise_if_exception(ret);
+
+  return rb_ary_new_from_args(2, INT2NUM(infop.si_pid), INT2NUM(infop.si_status));
+}
+
 /*******************************************************************************
                             multishot ops
 *******************************************************************************/

ext/um/um.h

@@ -193,6 +193,7 @@ VALUE um_read_each(struct um *machine, int fd, int bgid);
 VALUE um_write(struct um *machine, int fd, VALUE str, int len);
 VALUE um_close(struct um *machine, int fd);
 VALUE um_open(struct um *machine, VALUE pathname, int flags, int mode);
+VALUE um_waitpid(struct um *machine, int pid, int options);
 
 VALUE um_accept(struct um *machine, int fd);
 VALUE um_accept_each(struct um *machine, int fd);

ext/um/um_class.c

@@ -272,13 +272,18 @@ VALUE UM_open_ensure(VALUE arg) {
 VALUE UM_open(VALUE self, VALUE pathname, VALUE flags) {
   struct um *machine = get_machine(self);
   // TODO: take optional perm (mode) arg
-  VALUE ret = um_open(machine, pathname, NUM2INT(flags), 0666);
+  VALUE fd = um_open(machine, pathname, NUM2INT(flags), 0666);
   if (rb_block_given_p()) {
-    struct um_open_ctx ctx = { self, ret };
-    return rb_ensure(rb_yield, ret, UM_open_ensure, (VALUE)&ctx);
+    struct um_open_ctx ctx = { self, fd };
+    return rb_ensure(rb_yield, fd, UM_open_ensure, (VALUE)&ctx);
   }
   else
-    return ret;
+    return fd;
+}
+
+VALUE UM_waitpid(VALUE self, VALUE pid, VALUE options) {
+  struct um *machine = get_machine(self);
+  return um_waitpid(machine, NUM2INT(pid), NUM2INT(options));
 }
 
 VALUE UM_pipe(VALUE self) {
@@ -322,6 +327,8 @@ void Init_UM(void) {
   rb_define_method(cUM, "sleep", UM_sleep, 1);
   rb_define_method(cUM, "write", UM_write, -1);
 
+  rb_define_method(cUM, "waitpid", UM_waitpid, 2);
+
   rb_define_method(cUM, "accept", UM_accept, 1);
   rb_define_method(cUM, "accept_each", UM_accept_each, 1);
   rb_define_method(cUM, "bind", UM_bind, 3);

ext/um/um_const.c

@@ -1,6 +1,7 @@
 #include "ruby.h"
 
 #include <fcntl.h>
+#include <sys/wait.h>
 
 #include <arpa/inet.h>
 #include <sys/types.h>
@@ -32,6 +33,14 @@ void um_define_net_constants(VALUE mod) {
   DEF_CONST_INT(mod, O_TRUNC);
   DEF_CONST_INT(mod, O_WRONLY);
 
+  DEF_CONST_INT(mod, WNOHANG);
+  DEF_CONST_INT(mod, WUNTRACED);
+  DEF_CONST_INT(mod, WCONTINUED);
+  DEF_CONST_INT(mod, WEXITED);
+  DEF_CONST_INT(mod, WSTOPPED);
+  DEF_CONST_INT(mod, WCONTINUED);
+  DEF_CONST_INT(mod, WNOWAIT);
+
   DEF_CONST_INT(mod, SOCK_STREAM);
   DEF_CONST_INT(mod, SOCK_DGRAM);
   DEF_CONST_INT(mod, SOCK_RAW);

test/test_um.rb

@@ -992,6 +992,11 @@ def test_open_with_block
     assert_raises(Errno::EBADF) { machine.close(res) }
     assert_equal 'bar', IO.read(PATH)
   end
+
+  def test_open_bad_arg
+    assert_raises(Errno::ENOENT) { machine.open(PATH, UM::O_RDONLY) }
+    assert_raises(Errno::ENOENT) { machine.open(PATH, UM::O_RDONLY) {} }
+  end
 end
 
 class PipeTest < UMBaseTest
@@ -1014,11 +1019,31 @@ def test_pipe
   end
 end
 
-# class WaitIDTest < UMBaseTest
-#   def test_waitid
-#     rfd, wfd = UM.pipe
-#     pid = fork do
-#       exit 42
-#     end
-#   end
-# end
+class WaitTest < UMBaseTest
+  def test_waitpid
+    msg = 'hello from child'
+
+    rfd, wfd = UM.pipe
+    pid = fork do
+      m = UM.new
+      m.write(wfd, msg)
+      m.close(wfd)
+      exit 42
+    end
+
+    ret = machine.waitpid(pid, UM::WEXITED)
+    assert_kind_of Array, ret
+    assert_equal [pid, 42], ret
+
+    buf = +''
+    ret = machine.read(rfd, buf, 8192)
+    assert_equal msg.bytesize, ret
+    assert_equal msg, buf
+  end
+
+  def test_waitpid_bad_pid
+    assert_raises(Errno::ECHILD) { machine.waitpid(1, UM::WEXITED) }    
+  end
+
+end
+