igt/shell: First attempt at instantiating an object to wrap OS

5 files changed, 218 insertions, 0 deletions

diff --git a/shell/include/os.h b/shell/include/os.h
new file mode 100644
index 00000000..6e1f01de
--- /dev/null
+++ b/shell/include/os.h
@@ -0,0 +1,10 @@
+#ifndef OS_H
+#define OS_H
+
+#include "v8.h"
+
+extern void os_file_ctor(v8::Isolate *iso, v8::Handle<v8::ObjectTemplate> os);
+
+extern void os_throw_errno(v8::Isolate *iso, int err);
+
+#endif /* OS_H */
diff --git a/shell/lib/os-file.cc b/shell/lib/os-file.cc
new file mode 100644
index 00000000..c10f02df
--- /dev/null
+++ b/shell/lib/os-file.cc
@@ -0,0 +1,88 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "igt-shell.h"
+#include "os.h"
+#include "v8-helpers.h"
+
+using namespace v8;
+
+static void os_open(const FunctionCallbackInfo<Value>& args)
+{
+  auto iso = args.GetIsolate();
+
+  if (args.Length() < 1 || args.Length() > 2)
+    return;
+
+  if (!args[0]->IsString()) {
+    return;
+  }
+
+  int mode = O_RDONLY | O_CLOEXEC;
+  if (args.Length() > 1 && args[1]->IsUint32())
+    mode = args[1]->Uint32Value();
+
+  String::Utf8Value filename(iso, Local<String>::Cast(args[0]));
+  int fd = open(*filename, mode);
+  if (fd < 0) {
+    os_throw_errno(iso, errno);
+    return;
+  }
+
+  args.GetReturnValue().Set(fd);
+}
+
+static void os_reopen(const FunctionCallbackInfo<Value>& args)
+{
+  auto iso = args.GetIsolate();
+
+  if (args.Length() < 1 || !args[0]->IsInt32()) {
+      iso->ThrowException(Exception::TypeError(AsString(iso, "not an int32").ToLocalChecked()));
+    return;
+  }
+
+  char path[256];
+  snprintf(path, sizeof(path), "/proc/self/fd/%d", args[0]->Int32Value());
+
+  int mode = O_RDONLY | O_CLOEXEC;
+  if (args.Length() > 1 && args[1]->IsUint32())
+    mode = args[1]->Uint32Value();
+
+  int fd = open(path, mode);
+  if (fd < 0)
+    os_throw_errno(iso, errno);
+
+  args.GetReturnValue().Set(fd);
+}
+
+static void os_close(const FunctionCallbackInfo<Value>& args)
+{
+  auto iso = args.GetIsolate();
+
+  for (int i = 0; i < args.Length(); i++) {
+    Local<Value> v = args[i];
+
+    if (!v->IsInt32()) {
+      iso->ThrowException(Exception::TypeError(AsString(iso, "not an int32").ToLocalChecked()));
+      continue;
+    }
+
+    if (close(v->Int32Value()))
+      os_throw_errno(iso, errno);
+  }
+}
+
+void os_file_ctor(Isolate *iso, Handle<ObjectTemplate> os)
+{
+  HandleScope handle_scope(iso);
+
+  static const struct v8_helper_fn funcs[] = {
+    { "open", os_open },
+    { "reopen", os_reopen },
+    { "close", os_close },
+
+    {}
+  };
+  v8_helper_funcs(iso, os, funcs);
+}
diff --git a/shell/lib/os.cc b/shell/lib/os.cc
new file mode 100644
index 00000000..64fe64eb
--- /dev/null
+++ b/shell/lib/os.cc
@@ -0,0 +1,109 @@
+#include <pwd.h>
+#include <grp.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "igt-shell.h"
+#include "os.h"
+#include "v8-helpers.h"
+
+using namespace v8;
+
+void os_throw_errno(Isolate *iso, int err)
+{
+  iso->ThrowException(Exception::Error(AsString(iso, "syscall").ToLocalChecked()));
+}
+
+static void os_drop_root(const FunctionCallbackInfo<Value>& args)
+{
+  auto iso = args.GetIsolate();
+
+  /* Arbitrary default values for nobody:video */
+  uid_t uid = 65534;
+  gid_t gid = 44;
+
+  if (getuid())
+    return; /* already a user */
+
+  struct passwd *pw = getpwnam("nobody");
+  if (pw)
+    uid = pw->pw_uid, gid = pw->pw_gid;
+
+  struct group *grp = getgrnam("video");
+  if (grp)
+    gid = grp->gr_gid;
+
+  if (setgid(gid) || setuid(uid)) {
+    os_throw_errno(iso, errno);
+    return;
+  }
+}
+
+static void os_uid(Local<String> prop, const PropertyCallbackInfo<Value>& info)
+{
+  info.GetReturnValue().Set(Int32::New(info.GetIsolate(), getuid()));
+}
+
+static void os_sleep(const FunctionCallbackInfo<Value>& args)
+{
+  if (!args.Length()) {
+    sleep(0);
+    return;
+  }
+
+  auto iso = args.GetIsolate();
+  auto ctx = iso->GetCurrentContext();
+
+  if (!args[0]->IsNumber()) {
+      iso->ThrowException(Exception::TypeError(AsString(iso, "bad arg[0], expecting a Number").ToLocalChecked()));
+      return;
+  }
+
+  double t = args[0]->NumberValue(ctx).FromMaybe(0);
+  struct timespec ts = { (long)t, (long)(1e9*t) % 1000000000 };
+  nanosleep(&ts, NULL);
+}
+
+static void os_now(Local<String> prop, const PropertyCallbackInfo<Value>& info)
+{
+  auto iso = info.GetIsolate();
+
+  struct timespec ts;
+  if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
+    os_throw_errno(iso, errno);
+    return;
+  }
+  info.GetReturnValue().Set(Number::New(iso, 1e3*ts.tv_sec + 1e-6*ts.tv_nsec));
+}
+
+static void os_builtin_ctor(Isolate *iso, Handle<ObjectTemplate> igt)
+{
+  HandleScope handle_scope(iso);
+
+  auto tmpl = ObjectTemplate::New(iso);
+
+  static const struct v8_helper_fn os_funcs[] = {
+    { "drop_root", os_drop_root },
+    { "sleep", os_sleep },
+    {}
+  };
+  v8_helper_funcs(iso, tmpl, os_funcs);
+
+  tmpl->SetAccessor(AsString(iso, "uid").ToLocalChecked(), os_uid);
+  tmpl->SetAccessor(AsString(iso, "now").ToLocalChecked(), os_now);
+
+  os_file_ctor(iso, tmpl);
+
+  igt->Set(iso, "os", tmpl);
+}
+
+static struct igt_builtin os_builtin = {
+  .name = "os",
+  .ctor = os_builtin_ctor
+};
+
+__attribute__((constructor))
+static void __os_register_builtin__(void)
+{
+  igt_register_builtin(&os_builtin);
+}
diff --git a/shell/meson.build b/shell/meson.build
index 9868549e..a361172b 100644
--- a/shell/meson.build
+++ b/shell/meson.build
@@ -2,6 +2,8 @@ executable('igt', [
 	     'igt-shell.cc',
 	     'lib/igt.cc',
 	     'lib/igt-toy.cc',
+	     'lib/os.cc',
+	     'lib/os-file.cc',
 	     'lib/v8-helpers.cc',
 	   ],
 	   objects: 'v8/libv8_monolith.a',
diff --git a/shell/samples/os.sleep.js b/shell/samples/os.sleep.js
new file mode 100644
index 00000000..19f6aac9
--- /dev/null
+++ b/shell/samples/os.sleep.js
@@ -0,0 +1,9 @@
+let elapsed = -igt.os.now;
+let expected = 0;
+for (var i = 2; i > 0.1; i /= 2) {
+  print("Sleeping for " + i + "s");
+  igt.os.sleep(i);
+  expected += i;
+}
+elapsed += igt.os.now;
+print("Elapsed " + elapsed + "ms, expected " + expected*1000 + "ms");