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Extend pcntl_waitid with rusage parameter #15921

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Extend pcntl_waitid with rusage parameter #15921

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5 changes: 5 additions & 0 deletions ext/pcntl/config.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@ if test "$PHP_PCNTL" != "no"; then
wait3
wait4
waitid
wait6
syscall
]))

AC_CHECK_FUNCS([WIFCONTINUED],,
Expand All @@ -43,6 +45,9 @@ if test "$PHP_PCNTL" != "no"; then
]),,,
[#include <sys/wait.h>])

AC_CHECK_DECLS([SYS_waitid],,,
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@bukka bukka Jun 24, 2025 •
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@devnexen This is sort of an off topic but why SYS_pidfd_open is not checked in this way too. There is a check for pidfd_open function but how is that actually passing?

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yes indeed, I'll change that very soon. pidfd_open being a glibc wrapper exclusive (for now at least), it all worked for me locally.

[#include <sys/syscall.h>])

dnl if unsupported, -1 means automatically ENOSYS in this context
AC_CACHE_CHECK([if sched_getcpu is supported], [php_cv_func_sched_getcpu],
[AC_RUN_IFELSE([AC_LANG_SOURCE([
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46 changes: 42 additions & 4 deletions ext/pcntl/pcntl.c
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Expand Up @@ -125,7 +125,15 @@ typedef psetid_t cpu_set_t;
#include <pthread/qos.h>
#endif

#ifdef HAVE_PIDFD_OPEN
#if defined(__linux__) && defined(HAVE_DECL_SYS_WAITID) && HAVE_DECL_SYS_WAITID == 1 && defined(HAVE_SYSCALL)
#define HAVE_LINUX_RAW_SYSCALL_WAITID 1
#endif

#if defined(HAVE_LINUX_RAW_SYSCALL_WAITID)
#include <unistd.h>
#endif

#if defined(HAVE_PIDFD_OPEN) || defined(HAVE_LINUX_RAW_SYSCALL_WAITID)
#include <sys/syscall.h>
#endif

Expand Down Expand Up @@ -401,19 +409,49 @@ PHP_FUNCTION(pcntl_waitid)
bool id_is_null = 1;
zval *user_siginfo = NULL;
zend_long options = WEXITED;
zval *z_rusage = NULL;

ZEND_PARSE_PARAMETERS_START(0, 4)
siginfo_t siginfo;
int status;

ZEND_PARSE_PARAMETERS_START(0, 5)
Z_PARAM_OPTIONAL
Z_PARAM_LONG(idtype)
Z_PARAM_LONG_OR_NULL(id, id_is_null)
Z_PARAM_ZVAL(user_siginfo)
Z_PARAM_LONG(options)
Z_PARAM_ZVAL(z_rusage)
ZEND_PARSE_PARAMETERS_END();

errno = 0;
siginfo_t siginfo;
memset(&siginfo, 0, sizeof(siginfo_t));

int status = waitid((idtype_t) idtype, (id_t) id, &siginfo, (int) options);
#if defined(HAVE_WAIT6) || defined(HAVE_LINUX_RAW_SYSCALL_WAITID)
if (z_rusage) {
z_rusage = zend_try_array_init(z_rusage);
if (!z_rusage) {
RETURN_THROWS();
}
struct rusage rusage;
# if defined(HAVE_WAIT6) /* FreeBSD */
struct __wrusage wrusage;
memset(&wrusage, 0, sizeof(struct __wrusage));
pid_t pid = wait6((idtype_t) idtype, (id_t) id, &status, (int) options, &wrusage, &siginfo);
status = pid > 0 ? 0 : pid;
memcpy(&rusage, &wrusage.wru_self, sizeof(struct rusage));
# else /* Linux */
memset(&rusage, 0, sizeof(struct rusage));
status = syscall(SYS_waitid, (idtype_t) idtype, (id_t) id, &siginfo, (int) options, &rusage);
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Not sure if I like using undocumented syscalls ... There are already some syscalls used here so I'm not objecting but not sure if there is much value in it.

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@bukka Thanks for the review!

I agree that having to use the raw waitid syscall is not very elegant. However the rusage argument to it is actually documented in the wait(2) man page (under VERSIONS). So Linux officially supports this, it's just that glibc seems to be lagging slightly with the wait6 wrapper.

I think it's nice to round off the PHP pcntl_wait* function family functionality with a rich and consistent API, such as FreeBSD and NetBSD have with wait3, wait4 and wait6 (OpenBSD doesn't yet have wait6).

GNU libc has had wait3 and wait4 for a long time, and historically they were aiming at full support for the BSD APIs as well as POSIX and SysV, but it seems that they haven't gotten around to adding wait6 yet. When glibc gets wait6 we can simplify these ifdefs slightly. If I find time I'll look into sending them a patch.

# endif
if (status == 0) {
PHP_RUSAGE_TO_ARRAY(rusage, z_rusage);
}
} else { /* POSIX */
status = waitid((idtype_t) idtype, (id_t) id, &siginfo, (int) options);
}
#else /* POSIX */
status = waitid((idtype_t) idtype, (id_t) id, &siginfo, (int) options);
#endif

if (status == -1) {
PCNTL_G(last_error) = errno;
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7 changes: 5 additions & 2 deletions ext/pcntl/pcntl.stub.php
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Expand Up @@ -1006,8 +1006,11 @@ function pcntl_fork(): int {}
function pcntl_waitpid(int $process_id, &$status, int $flags = 0, &$resource_usage = []): int {}

#if defined (HAVE_WAITID) && defined (HAVE_POSIX_IDTYPES) && defined (HAVE_DECL_WEXITED) && HAVE_DECL_WEXITED == 1
/** @param array $info */
function pcntl_waitid(int $idtype = P_ALL, ?int $id = null, &$info = [], int $flags = WEXITED): bool {}
/**
* @param array $info
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not sure if we have to bother with these thus asking the stub wizard assistance :) once confirmed I ll merge shortly. Thanks for your work.

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@kocsismate Could you please take a quick look at the stub?

* @param array $resource_usage
*/
function pcntl_waitid(int $idtype = P_ALL, ?int $id = null, &$info = [], int $flags = WEXITED, &$resource_usage = []): bool {}
#endif

/**
Expand Down
3 changes: 2 additions & 1 deletion ext/pcntl/pcntl_arginfo.h
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10 changes: 6 additions & 4 deletions ext/pcntl/tests/pcntl_waitid.phpt
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Expand Up @@ -26,10 +26,12 @@ if ($pid == -1) {
} else {
pcntl_signal(SIGUSR1, function ($_signo, $_siginfo) { exit(42); });
posix_kill(posix_getpid(), SIGSTOP);
pcntl_signal_dispatch();
sleep(42);
pcntl_signal_dispatch();
exit(6);
$nanoseconds = 100;
while (true) {
pcntl_signal_dispatch();
time_nanosleep(0, $nanoseconds);
$nanoseconds *= 2;
}
}
?>
--EXPECTF--
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72 changes: 72 additions & 0 deletions ext/pcntl/tests/pcntl_waitid_rusage.phpt
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@@ -0,0 +1,72 @@
--TEST--
pcntl_waitid() and rusage
--EXTENSIONS--
pcntl
posix
--SKIPIF--
<?php
if (!function_exists('pcntl_waitid')) die('skip pcntl_waitid unavailable');
if (!str_contains(PHP_OS, 'Linux') && !str_contains(PHP_OS, 'FreeBSD')) {
die('skip pcntl_waitid can return rusage only on FreeBSD and Linux');
}
?>
--FILE--
<?php
$pid = pcntl_fork();
if ($pid == -1) {
die('failed');
} else if ($pid) {
var_dump(pcntl_waitid(P_PID, $pid, $siginfo, WSTOPPED, $rusage));
var_dump($rusage['ru_utime.tv_sec']);
var_dump($rusage['ru_utime.tv_usec']);

$rusage = array(1,2,3);
posix_kill($pid, SIGCONT);
var_dump(pcntl_waitid(P_PID, $pid, $siginfo, WCONTINUED, $rusage));
var_dump($rusage['ru_utime.tv_sec']);
var_dump($rusage['ru_utime.tv_usec']);

posix_kill($pid, SIGUSR1);
var_dump(pcntl_waitid(P_PID, $pid, $siginfo, WEXITED, $rusage));
var_dump($rusage['ru_maxrss']);
var_dump($siginfo['status']);

$rusage = 'string';
var_dump(pcntl_waitid(P_PID, $pid, $siginfo, WEXITED | WNOHANG, $rusage));
var_dump(gettype($rusage));
var_dump(count($rusage));

$rusage = new stdClass;
var_dump(pcntl_waitid(P_PID, $pid, $siginfo, WEXITED | WNOHANG, $rusage));
var_dump(gettype($rusage));
var_dump(count($rusage));

fwrite(STDOUT, 'END' . PHP_EOL);
} else {
pcntl_signal(SIGUSR1, function ($_signo, $_siginfo) { exit(42); });
posix_kill(posix_getpid(), SIGSTOP);
$nanoseconds = 100;
while (true) {
pcntl_signal_dispatch();
time_nanosleep(0, $nanoseconds);
$nanoseconds *= 2;
}
}
?>
--EXPECTF--
bool(true)
int(%d)
int(%d)
bool(true)
int(%d)
int(%d)
bool(true)
int(%d)
int(42)
bool(false)
string(5) "array"
int(0)
bool(false)
string(5) "array"
int(0)
END