os,syscall: implement functions related to uid, gid and pid on js/wasm

This change implements the following functions on js/wasm:
- os.Chown
- os.Fchown
- os.Lchown
- syscall.Getuid
- syscall.Getgid
- syscall.Geteuid
- syscall.Getegid
- syscall.Getgroups
- syscall.Getpid
- syscall.Getppid
- syscall.Umask

Change-Id: Icdb0fafc02c9df6e9e3573542f8499c3464dc671
Reviewed-on: https://go-review.googlesource.com/c/go/+/154157
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 39 insertions, 8 deletions

diff --git a/src/syscall/syscall_js.go b/src/syscall/syscall_js.go
index 4dfcc6ed64..99f9a935fe 100644
--- a/src/syscall/syscall_js.go
+++ b/src/syscall/syscall_js.go
@@ -285,14 +285,45 @@ func Getwd() (wd string, err error) {
 	return string(buf[:n]), nil
 }
 
-func Getegid() int                      { return 1 }
-func Geteuid() int                      { return 1 }
-func Getgid() int                       { return 1 }
-func Getgroups() ([]int, error)         { return []int{1}, nil }
-func Getppid() int                      { return 2 }
-func Getpid() int                       { return 3 }
-func Gettimeofday(tv *Timeval) error    { return ENOSYS }
-func Getuid() int                       { return 1 }
+func Getuid() int {
+	return jsProcess.Call("getuid").Int()
+}
+
+func Getgid() int {
+	return jsProcess.Call("getgid").Int()
+}
+
+func Geteuid() int {
+	return jsProcess.Call("geteuid").Int()
+}
+
+func Getegid() int {
+	return jsProcess.Call("getegid").Int()
+}
+
+func Getgroups() ([]int, error) {
+	array := jsProcess.Call("getgroups")
+	groups := make([]int, array.Length())
+	for i := range groups {
+		groups[i] = array.Index(i).Int()
+	}
+	return groups, nil
+}
+
+func Getpid() int {
+	return jsProcess.Get("pid").Int()
+}
+
+func Getppid() int {
+	return jsProcess.Get("ppid").Int()
+}
+
+func Umask(mask int) (oldmask int) {
+	return jsProcess.Call("umask", mask).Int()
+}
+
+func Gettimeofday(tv *Timeval) error { return ENOSYS }
+
 func Kill(pid int, signum Signal) error { return ENOSYS }
 func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
 	return 0, ENOSYS