ext/pcntl: cpu affinity api introduction.

For now, working on Linux, FreeBSD >= 13.x and DragonFlyBSD.
Handy wrapper to assign an array of cpu ids or to retrieve the cpu ids
assigned to a given process.

Author: devnexen

ext/pcntl/config.m4

@@ -7,7 +7,18 @@ if test "$PHP_PCNTL" != "no"; then
   AC_CHECK_FUNCS([fork], [], [AC_MSG_ERROR([pcntl: fork() not supported by this platform])])
   AC_CHECK_FUNCS([waitpid], [], [AC_MSG_ERROR([pcntl: waitpid() not supported by this platform])])
   AC_CHECK_FUNCS([sigaction], [], [AC_MSG_ERROR([pcntl: sigaction() not supported by this platform])])
-  AC_CHECK_FUNCS([getpriority setpriority wait3 wait4 sigwaitinfo sigtimedwait unshare rfork forkx pidfd_open])
+  AC_CHECK_FUNCS([
+	getpriority
+	setpriority
+	wait3
+	wait4
+	sigwaitinfo
+	sigtimedwait
+	unshare
+	rfork 
+	forkx
+	pidfd_open
+	sched_setaffinity])
 
   AC_CHECK_TYPE([siginfo_t],[PCNTL_CFLAGS="-DHAVE_STRUCT_SIGINFO_T"],,[#include <signal.h>])
 

ext/pcntl/pcntl.c

@@ -42,8 +42,13 @@
 #endif
 
 #include <errno.h>
-#ifdef HAVE_UNSHARE
+#if defined(HAVE_UNSHARE) || defined(HAVE_SCHED_SETAFFINITY)
 #include <sched.h>
+#if defined(__FreeBSD__)
+#include <sys/types.h>
+#include <sys/cpuset.h>
+typedef cpuset_t cpu_set_t;
+#endif
 #endif
 
 #ifdef HAVE_PIDFD_OPEN
@@ -1476,6 +1481,102 @@ PHP_FUNCTION(pcntl_setns)
 }
 #endif
 
+#ifdef HAVE_SCHED_SETAFFINITY
+PHP_FUNCTION(pcntl_getcpuaffinity)
+{
+	zend_long pid;
+	bool pid_is_null = 1;
+	cpu_set_t mask;
+	zend_ulong i, maxcpus;
+
+	ZEND_PARSE_PARAMETERS_START(0, 1)
+		Z_PARAM_OPTIONAL
+		Z_PARAM_LONG_OR_NULL(pid, pid_is_null)
+	ZEND_PARSE_PARAMETERS_END();
+
+	// 0 == getpid in this context, we re just saving a syscall
+	pid = pid_is_null ? 0 : pid;
+
+	CPU_ZERO(&mask);
+
+	if (sched_getaffinity(pid, sizeof(mask), &mask) != 0) {
+		PCNTL_G(last_error) = errno;
+		switch (errno) {
+			case ESRCH:
+				zend_argument_value_error(1, "invalid process (" ZEND_LONG_FMT ")", pid);
+				RETURN_THROWS();
+			case EPERM:
+				php_error_docref(NULL, E_WARNING, "Calling process not having the proper privileges");
+				break;
+			default:
+				php_error_docref(NULL, E_WARNING, "Error %d", errno);
+		}
+
+		RETURN_EMPTY_ARRAY();
+	}
+
+	maxcpus = (zend_ulong)sysconf(_SC_NPROCESSORS_ONLN);
+	array_init(return_value);
+
+	for (i = 0; i < maxcpus; i ++) {
+		if (CPU_ISSET(i, &mask)) {
+			add_next_index_long(return_value, i);
+		}
+	}
+}
+
+PHP_FUNCTION(pcntl_setcpuaffinity)
+{
+	zend_long pid;
+	bool pid_is_null = 1;
+	cpu_set_t mask;
+	zval *hmask = NULL, *cpu;
+	zend_ulong maxcpus;
+
+	ZEND_PARSE_PARAMETERS_START(0, 2)
+		Z_PARAM_OPTIONAL
+		Z_PARAM_LONG_OR_NULL(pid, pid_is_null)
+		Z_PARAM_ARRAY(hmask)
+	ZEND_PARSE_PARAMETERS_END();
+
+	if (!hmask || Z_ARRVAL_P(hmask)->nNumOfElements == 0) {
+		zend_argument_value_error(2, "must not be empty");
+		RETURN_THROWS();
+	}
+
+	pid = pid_is_null ? 0 : pid;
+	maxcpus = sysconf(_SC_NPROCESSORS_ONLN);
+	CPU_ZERO(&mask);
+
+	ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(hmask), cpu) {
+		if (Z_TYPE_P(cpu) == IS_LONG && Z_LVAL_P(cpu) >= 0 &&
+                    Z_LVAL_P(cpu) < maxcpus && !CPU_ISSET(Z_LVAL_P(cpu), &mask)) {
+			CPU_SET(Z_LVAL_P(cpu), &mask);
+		}
+	} ZEND_HASH_FOREACH_END();
+
+	if (!CPU_COUNT(&mask)) {
+		zend_argument_value_error(2, "invalid cpu affinity mapping");
+		RETURN_THROWS();
+	}
+
+	if (sched_setaffinity(pid, sizeof(mask), &mask) != 0) {
+		PCNTL_G(last_error) = errno;
+		switch (errno) {
+			case ESRCH:
+				zend_argument_value_error(1, "invalid process (" ZEND_LONG_FMT ")", pid);
+				RETURN_THROWS();
+			case EPERM:
+				php_error_docref(NULL, E_WARNING, "Calling process not having the proper privileges");
+				break;
+		}
+		RETURN_FALSE;
+	} else {
+		RETURN_TRUE;
+	}
+}
+#endif
+
 static void pcntl_interrupt_function(zend_execute_data *execute_data)
 {
 	pcntl_signal_dispatch();

ext/pcntl/pcntl.stub.php

@@ -994,3 +994,8 @@ function pcntl_forkx(int $flags): int{}
 #ifdef HAVE_PIDFD_OPEN
 function pcntl_setns(?int $process_id = null, int $nstype = CLONE_NEWNET): bool {}
 #endif
+
+#ifdef HAVE_SCHED_SETAFFINITY
+function pcntl_getcpuaffinity(?int $process_id = null): array {}
+function pcntl_setcpuaffinity(?int $process_id = null, array $cpu_ids = []): bool {}
+#endif

ext/pcntl/pcntl_arginfo.h

@@ -0,0 +1,46 @@
+--TEST--
+pcntl_getcpuaffinity() and pcntl_setcpuaffinity()
+--EXTENSIONS--
+pcntl
+--SKIPIF--
+<?php
+if (!function_exists("pcntl_setcpuaffinity")) die("skip pcntl_setcpuaffinity is not available");
+?>
+--FILE--
+<?php
+$mask = [0, 1];
+var_dump(pcntl_setcpuaffinity(null, $mask));
+$act_mask = pcntl_getcpuaffinity();
+var_dump(array_diff($mask, $act_mask));
+var_dump(pcntl_setcpuaffinity(null, [PHP_INT_MAX]));
+$n_act_mask = pcntl_getcpuaffinity();
+var_dump(array_diff($act_mask, $n_act_mask));
+
+try {
+	pcntl_setcpuaffinity(null, []);
+} catch (\ValueError $e) {
+	echo $e->getMessage() . PHP_EOL;
+}
+
+try {
+	pcntl_setcpuaffinity(null, [-1024, 64, -2]);
+} catch (\ValueError $e) {
+	echo $e->getMessage() . PHP_EOL;
+}
+
+try {
+	pcntl_getcpuaffinity(-1024);
+} catch (\ValueError $e) {
+	echo $e->getMessage();
+}
+?>
+--EXPECT--
+bool(true)
+array(0) {
+}
+bool(false)
+array(0) {
+}
+pcntl_setcpuaffinity(): Argument #2 ($cpu_ids) must not be empty
+pcntl_setcpuaffinity(): Argument #2 ($cpu_ids) invalid cpu affinity mapping
+pcntl_getcpuaffinity(): Argument #1 ($process_id) invalid process (-1024)