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Add the wait6(2) system call. It takes POSIX waitid()-like process

Browse Source 
designator to select a process which is waited for. The system call
optionally returns siginfo_t which would be otherwise provided to
SIGCHLD handler, as well as extended structure accounting for child
and cumulative grandchild resource usage.

Allow to get the current rusage information for non-exited processes
as well, similar to Solaris.

The explicit WEXITED flag is required to wait for exited processes,
allowing for more fine-grained control of the events the waiter is
interested in.

Fix the handling of siginfo for WNOWAIT option for all wait*(2)
family, by not removing the queued signal state.

PR:	standards/170346
Submitted by:	"Jukka A. Ukkonen" <jau@iki.fi>
MFC after:	1 month
This commit is contained in:
Konstantin Belousov 2012-11-13 12:52:31 +00:00
parent 84590fd8e5
commit f13b5a0f01
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=242958
13 changed files with 391 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/bsm/audit_kevents.h
View File

@ -602,6 +602,7 @@
#define AUE_PDKILL 43198 /* FreeBSD. */
#define AUE_PDGETPID 43199 /* FreeBSD. */
#define AUE_PDWAIT 43200 /* FreeBSD. */
#define AUE_WAIT6 43201 /* FreeBSD. */
/*
* Darwin BSM uses a number of AUE_O_* definitions, which are aliased to the

4
sys/cddl/contrib/opensolaris/uts/common/sys/procset.h
View File

@ -51,6 +51,7 @@ extern "C" {
#define P_INITUID 0
#define P_INITPGID 0
#ifndef _IDTYPE_T_DECLARED
/*
* The following defines the values for an identifier type. It
@ -81,6 +82,9 @@ typedef enum
P_PSETID /* Processor set identifier */
} idtype_t;
#define _IDTYPE_T_DECLARED
#endif
/*
* The following defines the operations which can be performed to

5
sys/compat/freebsd32/freebsd32.h
View File

@ -88,6 +88,11 @@ struct rusage32 {
int32_t ru_nivcsw;
};
struct wrusage32 {
struct rusage32 wru_self;
struct rusage32 wru_children;
};
struct itimerval32 {
struct timeval32 it_interval;
struct timeval32 it_value;

38
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -180,6 +180,44 @@ freebsd32_wait4(struct thread *td, struct freebsd32_wait4_args *uap)
return (error);
}
int
freebsd32_wait6(struct thread *td, struct freebsd32_wait6_args *uap)
{
struct wrusage32 wru32;
struct __wrusage wru, *wrup;
struct siginfo32 si32;
struct __siginfo si, *sip;
int error, status;
if (uap->wrusage != NULL)
wrup = &wru;
else
wrup = NULL;
if (uap->info != NULL) {
sip = &si;
bzero(sip, sizeof(*sip));
} else
sip = NULL;
error = kern_wait6(td, uap->idtype, uap->id, &status, uap->options,
wrup, sip);
if (error != 0)
return (error);
if (uap->status != NULL)
error = copyout(&status, uap->status, sizeof(status));
if (uap->wrusage != NULL && error == 0) {
freebsd32_rusage_out(&wru.wru_self, &wru32.wru_self);
freebsd32_rusage_out(&wru.wru_children, &wru32.wru_children);
error = copyout(&wru32, uap->wrusage, sizeof(wru32));
}
if (uap->info != NULL && error == 0) {
siginfo_to_siginfo32 (&si, &si32);
error = copyout(&si32, uap->info, sizeof(si32));
}
return (error);
}
#ifdef COMPAT_FREEBSD4
static void
copy_statfs(struct statfs *in, struct statfs32 *out)

5
sys/compat/freebsd32/syscalls.master
View File

@ -1000,3 +1000,8 @@
uint32_t offset1, uint32_t offset2,\
uint32_t len1, uint32_t len2, \
int advice); }
532 AUE_WAIT6 STD { int freebsd32_wait6(int idtype, int id, \
int *status, int options, \
struct wrusage32 *wrusage, \
siginfo_t *info); }

307
sys/kern/kern_exit.c
View File

@ -143,7 +143,7 @@ exit1(struct thread *td, int rv)
* XXX in case we're rebooting we just let init die in order to
* work around an unsolved stack overflow seen very late during
* shutdown on sparc64 when the gmirror worker process exists.
*/
*/
if (p == initproc && rebooting == 0) {
printf("init died (signal %d, exit %d)\n",
WTERMSIG(rv), WEXITSTATUS(rv));
@ -617,7 +617,7 @@ sys_abort2(struct thread *td, struct abort2_args *uap)
sbuf_clear(sb);
sbuf_printf(sb, "%s(pid %d uid %d) aborted: ",
p->p_comm, p->p_pid, td->td_ucred->cr_uid);
/*
/*
* Since we can't return from abort2(), send SIGKILL in cases, where
* abort2() was called improperly
*/
@ -689,7 +689,7 @@ owait(struct thread *td, struct owait_args *uap __unused)
* The dirty work is handled by kern_wait().
*/
int
sys_wait4(struct thread *td, struct wait_args *uap)
sys_wait4(struct thread *td, struct wait4_args *uap)
{
struct rusage ru, *rup;
int error, status;
@ -706,14 +706,51 @@ sys_wait4(struct thread *td, struct wait_args *uap)
return (error);
}
int
sys_wait6(struct thread *td, struct wait6_args *uap)
{
struct __wrusage wru, *wrup;
siginfo_t si, *sip;
int error, status;
idtype_t idtype;
id_t id;
idtype = uap->idtype;
id = uap->id;
if (uap->wrusage != NULL)
wrup = &wru;
else
wrup = NULL;
if (uap->info != NULL) {
sip = &si;
bzero(sip, sizeof(*sip));
} else
sip = NULL;
/*
* We expect all callers of wait6() to know about WEXITED and
* WTRAPPED.
*/
error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip);
if (uap->status != NULL && error == 0)
error = copyout(&status, uap->status, sizeof(status));
if (uap->wrusage != NULL && error == 0)
error = copyout(&wru, uap->wrusage, sizeof(wru));
if (uap->info != NULL && error == 0)
error = copyout(&si, uap->info, sizeof(si));
return (error);
}
/*
* Reap the remains of a zombie process and optionally return status and
* rusage. Asserts and will release both the proctree_lock and the process
* lock as part of its work.
*/
void
proc_reap(struct thread *td, struct proc *p, int *status, int options,
struct rusage *rusage)
proc_reap(struct thread *td, struct proc *p, int *status, int options)
{
struct proc *q, *t;
@ -723,10 +760,7 @@ proc_reap(struct thread *td, struct proc *p, int *status, int options,
KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
q = td->td_proc;
if (rusage) {
*rusage = p->p_ru;
calcru(p, &rusage->ru_utime, &rusage->ru_stime);
}
PROC_SUNLOCK(p);
td->td_retval[0] = p->p_pid;
if (status)
@ -839,20 +873,74 @@ proc_reap(struct thread *td, struct proc *p, int *status, int options,
}
static int
proc_to_reap(struct thread *td, struct proc *p, pid_t pid, int *status,
int options, struct rusage *rusage)
proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo)
{
struct proc *q;
struct rusage *rup;
sx_assert(&proctree_lock, SA_XLOCKED);
q = td->td_proc;
PROC_LOCK(p);
if (pid != WAIT_ANY && p->p_pid != pid && p->p_pgid != -pid) {
switch (idtype) {
case P_ALL:
break;
case P_PID:
if (p->p_pid != (pid_t)id) {
PROC_UNLOCK(p);
return (0);
}
break;
case P_PGID:
if (p->p_pgid != (pid_t)id) {
PROC_UNLOCK(p);
return (0);
}
break;
case P_SID:
if (p->p_session->s_sid != (pid_t)id) {
PROC_UNLOCK(p);
return (0);
}
break;
case P_UID:
if (p->p_ucred->cr_uid != (uid_t)id) {
PROC_UNLOCK(p);
return (0);
}
break;
case P_GID:
if (p->p_ucred->cr_gid != (gid_t)id) {
PROC_UNLOCK(p);
return (0);
}
break;
case P_JAILID:
if (p->p_ucred->cr_prison == NULL ||
(p->p_ucred->cr_prison->pr_id != (int)id)) {
PROC_UNLOCK(p);
return (0);
}
break;
/*
* It seems that the thread structures get zeroed out
* at process exit. This makes it impossible to
* support P_SETID, P_CID or P_CPUID.
*/
default:
PROC_UNLOCK(p);
return (0);
break;
}
if (p_canwait(td, p)) {
PROC_UNLOCK(p);
return (0);
}
if (p_canwait(td, p)) {
if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) {
PROC_UNLOCK(p);
return (0);
}
@ -872,8 +960,59 @@ proc_to_reap(struct thread *td, struct proc *p, pid_t pid, int *status,
}
PROC_SLOCK(p);
if (siginfo != NULL) {
bzero (siginfo, sizeof (*siginfo));
siginfo->si_errno = 0;
/*
* SUSv4 requires that the si_signo value is always
* SIGCHLD. Obey it despite the rfork(2) interface
* allows to request other signal for child exit
* notification.
*/
siginfo->si_signo = SIGCHLD;
/*
* This is still a rough estimate. We will fix the
* cases TRAPPED, STOPPED, and CONTINUED later.
*/
if (WCOREDUMP(p->p_xstat))
siginfo->si_code = CLD_DUMPED;
else if (WIFSIGNALED(p->p_xstat))
siginfo->si_code = CLD_KILLED;
else
siginfo->si_code = CLD_EXITED;
siginfo->si_pid = p->p_pid;
siginfo->si_uid = p->p_ucred->cr_uid;
siginfo->si_status = p->p_xstat;
/*
* The si_addr field would be useful additional
* detail, but apparently the PC value may be lost
* when we reach this point. bzero() above sets
* siginfo->si_addr to NULL.
*/
}
/*
* There should be no reason to limit resources usage info to
* exited processes only. A snapshot about any resources used
* by a stopped process may be exactly what is needed.
*/
if (wrusage != NULL) {
rup = &wrusage->wru_self;
*rup = p->p_ru;
calcru(p, &rup->ru_utime, &rup->ru_stime);
rup = &wrusage->wru_children;
*rup = p->p_stats->p_cru;
calccru(p, &rup->ru_utime, &rup->ru_stime);
}
if (p->p_state == PRS_ZOMBIE) {
proc_reap(td, p, status, options, rusage);
proc_reap(td, p, status, options);
return (-1);
}
PROC_SUNLOCK(p);
@ -884,22 +1023,72 @@ proc_to_reap(struct thread *td, struct proc *p, pid_t pid, int *status,
int
kern_wait(struct thread *td, pid_t pid, int *status, int options,
struct rusage *rusage)
{
struct __wrusage wru, *wrup;
idtype_t idtype;
id_t id;
int ret;
if (pid == WAIT_ANY) {
idtype = P_ALL;
id = 0;
}
else if (pid <= 0) {
idtype = P_PGID;
id = (id_t)-pid;
}
else {
idtype = P_PID;
id = (id_t)pid;
}
if (rusage != NULL)
wrup = &wru;
else
wrup = NULL;
/*
* For backward compatibility we implicitly add flags WEXITED
* and WTRAPPED here.
*/
options |= WEXITED | WTRAPPED;
ret = kern_wait6(td, idtype, id, status, options, wrup, NULL);
if (rusage != NULL)
*rusage = wru.wru_self;
return (ret);
}
int
kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
int options, struct __wrusage *wrusage, siginfo_t *siginfo)
{
struct proc *p, *q;
int error, nfound, ret;
AUDIT_ARG_PID(pid);
AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */
AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */
AUDIT_ARG_VALUE(options);
q = td->td_proc;
if (pid == 0) {
PROC_LOCK(q);
pid = -q->p_pgid;
PROC_UNLOCK(q);
if ((pid_t)id == WAIT_MYPGRP &&
(idtype == P_PID || idtype == P_PGID)) {
id = (id_t)q->p_pgid;
idtype = P_PGID;
}
/* If we don't know the option, just return. */
if (options & ~(WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE))
if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT |
WEXITED | WTRAPPED | WLINUXCLONE)) != 0)
return (EINVAL);
if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) {
/*
* We will be unable to find any matching processes,
* because there are no known events to look for.
* Prefer to return error instead of blocking
* indefinitely.
*/
return (EINVAL);
}
loop:
if (q->p_flag & P_STATCHILD) {
PROC_LOCK(q);
@ -909,7 +1098,8 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
nfound = 0;
sx_xlock(&proctree_lock);
LIST_FOREACH(p, &q->p_children, p_sibling) {
ret = proc_to_reap(td, p, pid, status, options, rusage);
ret = proc_to_reap(td, p, idtype, id, status, options,
wrusage, siginfo);
if (ret == 0)
continue;
else if (ret == 1)
@ -919,37 +1109,77 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
PROC_LOCK(p);
PROC_SLOCK(p);
if ((p->p_flag & P_STOPPED_SIG) &&
if ((options & WTRAPPED) != 0 &&
(p->p_flag & P_TRACED) != 0 &&
(p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 &&
(p->p_suspcount == p->p_numthreads) &&
(p->p_flag & P_WAITED) == 0 &&
(p->p_flag & P_TRACED || options & WUNTRACED)) {
((p->p_flag & P_WAITED) == 0)) {
PROC_SUNLOCK(p);
p->p_flag |= P_WAITED;
if ((options & WNOWAIT) == 0)
p->p_flag |= P_WAITED;
sx_xunlock(&proctree_lock);
td->td_retval[0] = p->p_pid;
if (status)
if (status != NULL)
*status = W_STOPCODE(p->p_xstat);
if (siginfo != NULL) {
siginfo->si_status = p->p_xstat;
siginfo->si_code = CLD_TRAPPED;
}
if ((options & WNOWAIT) == 0) {
PROC_LOCK(q);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(q);
}
PROC_LOCK(q);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(q);
PROC_UNLOCK(p);
return (0);
}
if ((options & WUNTRACED) != 0 &&
(p->p_flag & P_STOPPED_SIG) != 0 &&
(p->p_suspcount == p->p_numthreads) &&
((p->p_flag & P_WAITED) == 0)) {
PROC_SUNLOCK(p);
if ((options & WNOWAIT) == 0)
p->p_flag |= P_WAITED;
sx_xunlock(&proctree_lock);
td->td_retval[0] = p->p_pid;
if (status != NULL)
*status = W_STOPCODE(p->p_xstat);
if (siginfo != NULL) {
siginfo->si_status = p->p_xstat;
siginfo->si_code = CLD_STOPPED;
}
if ((options & WNOWAIT) == 0) {
PROC_LOCK(q);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(q);
}
PROC_UNLOCK(p);
return (0);
}
PROC_SUNLOCK(p);
if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
if ((options & WCONTINUED) != 0 &&
(p->p_flag & P_CONTINUED) != 0) {
sx_xunlock(&proctree_lock);
td->td_retval[0] = p->p_pid;
p->p_flag &= ~P_CONTINUED;
PROC_LOCK(q);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(q);
if ((options & WNOWAIT) == 0) {
p->p_flag &= ~P_CONTINUED;
PROC_LOCK(q);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(q);
}
PROC_UNLOCK(p);
if (status)
if (status != NULL)
*status = SIGCONT;
if (siginfo != NULL) {
siginfo->si_status = SIGCONT;
siginfo->si_code = CLD_CONTINUED;
}
return (0);
}
PROC_UNLOCK(p);
@ -968,7 +1198,8 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
* to successfully wait until the child becomes a zombie.
*/
LIST_FOREACH(p, &q->p_orphans, p_orphan) {
ret = proc_to_reap(td, p, pid, status, options, rusage);
ret = proc_to_reap(td, p, idtype, id, status, options,
wrusage, siginfo);
if (ret == 0)
continue;
else if (ret == 1)
@ -994,7 +1225,7 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
PROC_UNLOCK(q);
if (error)
return (error);
return (error);
goto loop;
}

2
sys/kern/sys_procdesc.c
View File

@ -374,7 +374,7 @@ procdesc_close(struct file *fp, struct thread *td)
*/
PROC_LOCK(p);
PROC_SLOCK(p);
proc_reap(curthread, p, NULL, 0, NULL);
proc_reap(curthread, p, NULL, 0);
} else {
/*
* If the process is not yet dead, we need to kill it, but we

7
sys/kern/syscalls.master
View File

@ -71,8 +71,7 @@
; XXX man page says `mode_t mode'.
6 AUE_CLOSE STD { int close(int fd); }
7 AUE_WAIT4 STD { int wait4(int pid, int *status, \
int options, struct rusage *rusage); } \
wait4 wait_args int
int options, struct rusage *rusage); }
8 AUE_CREAT COMPAT { int creat(char *path, int mode); }
9 AUE_LINK STD { int link(char *path, char *link); }
10 AUE_UNLINK STD { int unlink(char *path); }
@ -952,5 +951,9 @@
off_t offset, off_t len); }
531 AUE_NULL STD { int posix_fadvise(int fd, off_t offset, \
off_t len, int advice); }
532 AUE_WAIT6 STD { int wait6(int idtype, int id, \
int *status, int options, \
struct __wrusage *wrusage, \
siginfo_t *info); }
; Please copy any additions and changes to the following compatability tables:
; sys/compat/freebsd32/syscalls.master

3
sys/sys/proc.h
View File

@ -885,8 +885,7 @@ int proc_getenvv(struct thread *td, struct proc *p, struct sbuf *sb);
void procinit(void);
void proc_linkup0(struct proc *p, struct thread *td);
void proc_linkup(struct proc *p, struct thread *td);
void proc_reap(struct thread *td, struct proc *p, int *status, int options,
struct rusage *rusage);
void proc_reap(struct thread *td, struct proc *p, int *status, int options);
void proc_reparent(struct proc *child, struct proc *newparent);
struct pstats *pstats_alloc(void);
void pstats_fork(struct pstats *src, struct pstats *dst);

7
sys/sys/resource.h
View File

@ -79,6 +79,13 @@ struct rusage {
#define ru_last ru_nivcsw
};
#if __BSD_VISIBLE
struct __wrusage {
struct rusage wru_self;
struct rusage wru_children;
};
#endif
/*
* Resource limits
*/

3
sys/sys/syscallsubr.h
View File

@ -43,6 +43,7 @@ struct msghdr;
struct msqid_ds;
struct rlimit;
struct rusage;
struct __wrusage;
union semun;
struct sockaddr;
struct stat;
@ -234,6 +235,8 @@ int kern_utimesat(struct thread *td, int fd, char *path,
enum uio_seg pathseg, struct timeval *tptr, enum uio_seg tptrseg);
int kern_wait(struct thread *td, pid_t pid, int *status, int options,
struct rusage *rup);
int kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status,
int options, struct __wrusage *wrup, siginfo_t *sip);
int kern_writev(struct thread *td, int fd, struct uio *auio);
int kern_socketpair(struct thread *td, int domain, int type, int protocol,
int *rsv);

40
sys/sys/types.h
View File

@ -141,6 +141,46 @@ typedef __id_t id_t; /* can hold a uid_t or pid_t */
#define _ID_T_DECLARED
#endif
#ifndef _IDTYPE_T_DECLARED
typedef enum
#if defined(__BSD_VISIBLE)
idtype /* pollutes XPG4.2 namespace */
#endif
{
/*
* These names were mostly lifted from Solaris source code and
* still use Solaris style naming to avoid breaking any
* OpenSolaris code which has been ported to FreeBSD. There
* is no clear FreeBSD counterpart for all of the names, but
* some have a clear correspondence to FreeBSD entities.
*/
P_PID, /* A process identifier. */
P_PPID, /* A parent process identifier. */
P_PGID, /* A process group identifier. */
P_SID, /* A session identifier. */
P_CID, /* A scheduling class identifier. */
P_UID, /* A user identifier. */
P_GID, /* A group identifier. */
P_ALL, /* All processes. */
P_LWPID, /* An LWP identifier. */
P_TASKID, /* A task identifier. */
P_PROJID, /* A project identifier. */
P_POOLID, /* A pool identifier. */
P_JAILID, /* A zone identifier. */
P_CTID, /* A (process) contract identifier. */
P_CPUID, /* CPU identifier. */
P_PSETID /* Processor set identifier */
} idtype_t; /* The type of id_t we are using. */
#if defined(__BSD_VISIBLE)
#define P_ZONEID P_JAILID
#endif
#define _IDTYPE_T_DECLARED
#endif
#ifndef _INO_T_DECLARED
typedef __ino_t ino_t; /* inode number */
#define _INO_T_DECLARED

12
sys/sys/wait.h
View File

@ -80,6 +80,9 @@
#define WSTOPPED WUNTRACED /* SUS compatibility */
#define WCONTINUED 4 /* Report a job control continued process. */
#define WNOWAIT 8 /* Poll only. Don't delete the proc entry. */
#define WEXITED 16 /* Wait for exited processes. */
#define WTRAPPED 32 /* Wait for a process to hit a trap or
a breakpoint. */
#if __BSD_VISIBLE
#define WLINUXCLONE 0x80000000 /* Wait for kthread spawned from linux_clone. */
@ -87,6 +90,8 @@
/*
* Tokens for special values of the "pid" parameter to wait4.
* Extended struct __wrusage to collect rusage for both the target
* process and its children within one wait6() call.
*/
#if __BSD_VISIBLE
#define WAIT_ANY (-1) /* any process */
@ -97,12 +102,19 @@
#include <sys/types.h>
__BEGIN_DECLS
struct __siginfo;
pid_t wait(int *);
pid_t waitpid(pid_t, int *, int);
#if __POSIX_VISIBLE >= 200112
int waitid(idtype_t, id_t, struct __siginfo *, int);
#endif
#if __BSD_VISIBLE
struct rusage;
struct __wrusage;
pid_t wait3(int *, int, struct rusage *);
pid_t wait4(pid_t, int *, int, struct rusage *);
pid_t wait6(idtype_t, id_t, int *, int, struct __wrusage *,
struct __siginfo *);
#endif
__END_DECLS
#endif /* !_KERNEL */