feat(unix): add `poll`

core/os/os_linux.odin

@@ -432,6 +432,18 @@ AT_FDCWD            :: ~uintptr(99)	/* -100 */
 AT_REMOVEDIR        :: uintptr(0x200)
 AT_SYMLINK_NOFOLLOW :: uintptr(0x100)
 
+pollfd :: struct {
+  fd:      c.int,
+  events:  c.short,
+  revents: c.short,
+}
+
+nfds_t :: distinct c.uint
+
+sigset_t :: struct {
+  __val: [16]c.ulong,
+}
+
 foreign libc {
 	@(link_name="__errno_location") __errno_location    :: proc() -> ^int ---
 
@@ -1087,3 +1099,27 @@ fcntl :: proc(fd: int, cmd: int, arg: int) -> (int, Errno) {
 	}
 	return result, ERROR_NONE
 }
+
+// select :: proc(nfds: int, readfds: ^fd_set, writefds: ^fd_set, exceptfds: ^fd_set, timeout: ^timeval) -> (int, Errno) {
+//   result := unix.sys_select(nfds, readfds, writefds, exceptfds, timeout)
+//   if result < 0 {
+//     return 0, _get_errno(result)
+//   }
+//   return result, ERROR_NONE
+// }
+
+poll :: proc(fds: [^]pollfd, nfds: nfds_t, timeout: int) -> (int, Errno) {
+  result := unix.sys_poll(fds, uint(nfds), timeout)
+  if result < 0 {
+    return 0, _get_errno(result)
+  }
+  return result, ERROR_NONE
+}
+
+ppoll :: proc(fds: [^]pollfd, nfds: nfds_t, timeout: ^unix.timespec, sigmask: ^sigset_t) -> (int, Errno) {
+  result := unix.sys_ppoll(fds, uint(nfds), timeout, sigmask, size_of(sigset_t))
+  if result < 0 {
+    return 0, _get_errno(result)
+  }
+  return result, ERROR_NONE
+}

core/sys/unix/syscalls_linux.odin

@@ -1567,6 +1567,23 @@ MADV_HWPOISON    :: 100
 // pipe2 flags
 O_CLOEXEC :: 0o2000000
 
+// poll events
+POLLIN         :: 0x0001
+POLLPRI        :: 0x0002
+POLLOUT        :: 0x0004
+POLLERR        :: 0x0008
+POLLHUP        :: 0x0010
+POLLNVAL       :: 0x0020
+POLLRDNORM     :: 0x0040
+POLLRDBAND     :: 0x0080
+POLLWRNORM     :: 0x0100
+POLLWRBAND     :: 0x0200
+POLLMSG        :: 0x0400
+POLLREMOVE     :: 0x1000
+POLLRDHUP      :: 0x2000
+POLLFREE       :: 0x4000
+POLL_BUSY_LOOP :: 0x8000
+
 // perf event data
 Perf_Sample :: struct #raw_union {
 	period:    u64,
@@ -2057,6 +2074,18 @@ sys_fcntl :: proc "contextless" (fd: int, cmd: int, arg: int) -> int {
 	return int(intrinsics.syscall(SYS_fcntl, uintptr(fd), uintptr(cmd), uintptr(arg)))
 }
 
+sys_select :: proc "contextless" (nfds: int, readfds, writefds, exceptfds: rawptr, timeout: rawptr) -> int {
+  return int(intrinsics.syscall(SYS_select, uintptr(nfds), uintptr(readfds), uintptr(writefds), uintptr(exceptfds), uintptr(timeout)))
+}
+
+sys_poll :: proc "contextless" (fds: rawptr, nfds: uint, timeout: int) -> int {
+  return int(intrinsics.syscall(SYS_poll, uintptr(fds), uintptr(nfds), uintptr(timeout)))
+}
+
+sys_ppoll :: proc "contextless" (fds: rawptr, nfds: uint, timeout: rawptr, sigmask: rawptr, sigsetsize: uint) -> int {
+  return int(intrinsics.syscall(SYS_ppoll, uintptr(fds), uintptr(nfds), uintptr(timeout), uintptr(sigmask), uintptr(sigsetsize)))
+}
+
 get_errno :: proc "contextless" (res: int) -> i32 {
 	if res < 0 && res > -4096 {
 		return i32(-res)