#13546: wait4() doesn't seem to work
-------------------------------+------------------------------
Reporter: korli | Owner: nobody
Type: bug | Status: new
Priority: normal | Milestone: Unscheduled
Component: System/libroot.so | Version: R1/Development
Keywords: | Blocked By:
Blocking: | Has a Patch: 0
Platform: All |
-------------------------------+------------------------------
Test program:
{{{
/*
* Copyright 2007, Axel Dörfler, axeld@xxxxxxxxxxxxxxxx. All rights
reserved.
* Distributed under the terms of the MIT License.
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/resource.h>
#define _BSD_SOURCE
#include <sys/wait.h>
#include <unistd.h>
/*!
wait() should wait only once. If any argument is given, waitpid()
should return
an error (and errno to ECHILD), since there is no child with that
process group ID.
*/
int
child2()
{
sleep(2);
return 2;
}
//! exits before child 2
int
child1()
{
setpgrp();
// put us into a new process group
pid_t child = fork();
if (child == 0)
return child2();
sleep(1);
return 1;
}
int
main(int argc, char** argv)
{
bool waitForGroup = argc > 1;
pid_t child = fork();
if (child == 0)
return child1();
struct rusage usage;
pid_t pid;
do {
int childStatus = -1;
pid = wait4(-1, &childStatus, 0, &usage);
printf("wait4() returned %ld (%s), child status %d\n",
pid, strerror(errno), childStatus);
} while (pid >= 0);
return 0;
}
}}}
Haiku strace output
{{{
[ 581] _kern_image_relocated(0xf6d) (409 us)
[ 581] _kern_set_area_protection(0x2cce, 0x5) = 0x00000000 No error (11
us)
[ 581] _kern_set_area_protection(0x2cd0, 0x5) = 0x00000000 No error (10
us)
[ 581] _kern_set_area_protection(0x2cd2, 0x5) = 0x00000000 No error (23
us)
[ 581] _kern_get_system_info(0x72d84998) = 0x00000000 No error (7 us)
[ 581] _kern_get_system_info(0x72d84798) = 0x00000000 No error (4 us)
[ 581] _kern_reserve_address_range([0x18033000], 0x7, 0x48000000) =
0x00000000 No error (7 us)
[ 581] _kern_create_area("heap", 0xc6b980, 0x1, 0x40000, 0x0, 0x33) =
0x00002cd6 (15 us)
[ 581] _kern_fork() = 0x00000247 (241 us)
[ 581] _kern_wait_for_child(0xffffffff, 0x0, 0x72d84b64) = 0x00000247
(999999 us)
[ 581] --- Child exited (Child exited) ---
[ 581] _kern_get_team_usage_info(0x247, 0x0, 0x72d84bb8, 0x10) =
0x80001103 Operation on invalid team (2 us)
[ 581] _kern_read_stat(0x1, (nil), false, 0x72d83390, 0x58) = 0x00000000
No error (4 us)
[ 581] _kern_ioctl(0x1, TCGETA, 0x72d83338, 0x20) = 0x00000000 No error
(5 us)
wait4() returned -1 (No error), child status 1
[ 581] _kern_write(0x1, 0xffffffffffffffff, 0x180571b0, 0x2f) =
0x0000002f (1379 us)
[ 581] _kern_exit_team(0x0) (9 us)
}}}
Linux output
{{{
wait4() returned 22104 (Success), child status 256
wait4() returned 4294967295 (No child processes), child status -1
}}}
--
Ticket URL: <https://dev.haiku-os.org/ticket/13546>
Haiku <https://dev.haiku-os.org>
The Haiku operating system.
