wasi: refactor and enable poll_oneoff() test

This commit refactors and enables the poll_oneoff() WASI test.
The refactor includes testing additional cases, as well as some
platform specific checks.

PR-URL: #33521
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>

test/wasi/c/poll.c

@@ -2,30 +2,72 @@
 #include <poll.h>
 #include <time.h>
 #include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
 
 int main(void) {
-  struct pollfd fds[2];
+  struct pollfd fds[4];
   time_t before, now;
   int ret;
+  char* platform;
+  int is_aix;
+  int is_win;
 
+  platform = getenv("NODE_PLATFORM");
+  is_aix = platform != NULL && 0 == strcmp(platform, "aix");
+  is_win = platform != NULL && 0 == strcmp(platform, "win32");
+
+  // Test sleep() behavior.
+  time(&before);
+  sleep(1);
+  time(&now);
+  assert(now - before >= 1);
+
+  // Test poll() timeout behavior.
+  fds[0] = (struct pollfd){.fd = -1, .events = 0, .revents = 0};
+  time(&before);
+  ret = poll(fds, 1, 2000);
+  time(&now);
+  assert(ret == 0);
+  assert(now - before >= 2);
+
+  // The rest of the test is unsupported on Windows.
+  if (is_win)
+    return 0;
+
+  fds[0] = (struct pollfd){.fd = 1, .events = POLLOUT, .revents = 0};
+  fds[1] = (struct pollfd){.fd = 2, .events = POLLOUT, .revents = 0};
+
+  ret = poll(fds, 2, -1);
+  assert(ret == 2);
+  assert(fds[0].revents == POLLOUT);
+  assert(fds[1].revents == POLLOUT);
+
+  // Make a poll() call with duplicate file descriptors.
   fds[0] = (struct pollfd){.fd = 1, .events = POLLOUT, .revents = 0};
   fds[1] = (struct pollfd){.fd = 2, .events = POLLOUT, .revents = 0};
+  fds[2] = (struct pollfd){.fd = 1, .events = POLLOUT, .revents = 0};
+  fds[3] = (struct pollfd){.fd = 1, .events = POLLIN, .revents = 0};
 
   ret = poll(fds, 2, -1);
   assert(ret == 2);
   assert(fds[0].revents == POLLOUT);
   assert(fds[1].revents == POLLOUT);
+  assert(fds[2].revents == 0);
+  assert(fds[3].revents == 0);
 
+  // The original version of this test expected a timeout and return value of
+  // zero. In the Node test suite, STDIN is not a TTY, and poll() returns one,
+  // with revents = POLLHUP | POLLIN, except on AIX whose poll() does not
+  // support POLLHUP.
   fds[0] = (struct pollfd){.fd = 0, .events = POLLIN, .revents = 0};
-  time(&before);
   ret = poll(fds, 1, 2000);
-  time(&now);
-  assert(ret == 0);
-  assert(now - before >= 2);
+  assert(ret == 1);
 
-  sleep(1);
-  time(&now);
-  assert(now - before >= 3);
+  if (is_aix)
+    assert(fds[0].revents == POLLIN);
+  else
+    assert(fds[0].revents == (POLLHUP | POLLIN));
 
   return 0;
 }

test/wasi/test-wasi.js

@@ -38,7 +38,13 @@ if (process.argv[2] === 'wasi-child') {
 
   function runWASI(options) {
     console.log('executing', options.test);
-    const opts = { env: { ...process.env, NODE_DEBUG_NATIVE: 'wasi' } };
+    const opts = {
+      env: {
+        ...process.env,
+        NODE_DEBUG_NATIVE: 'wasi',
+        NODE_PLATFORM: process.platform
+      }
+    };
 
     if (options.stdin !== undefined)
       opts.input = options.stdin;
@@ -75,7 +81,7 @@ if (process.argv[2] === 'wasi-child') {
   runWASI({ test: 'link' });
   runWASI({ test: 'main_args' });
   runWASI({ test: 'notdir' });
-  // runWASI({ test: 'poll' });
+  runWASI({ test: 'poll' });
   runWASI({ test: 'preopen_populates' });
   runWASI({ test: 'read_file', stdout: `hello from input.txt${EOL}` });
   runWASI({