[Midnightbsd-cvs] src [7248] trunk/lib/libc: add userland piece for wait6 system call
laffer1 at midnightbsd.org
laffer1 at midnightbsd.org
Fri Aug 14 10:39:58 EDT 2015
Revision: 7248
http://svnweb.midnightbsd.org/src/?rev=7248
Author: laffer1
Date: 2015-08-14 10:39:58 -0400 (Fri, 14 Aug 2015)
Log Message:
-----------
add userland piece for wait6 system call
Modified Paths:
--------------
trunk/lib/libc/gen/Makefile.inc
trunk/lib/libc/include/namespace.h
trunk/lib/libc/include/un-namespace.h
trunk/lib/libc/sys/Makefile.inc
trunk/lib/libc/sys/Symbol.map
trunk/lib/libc/sys/wait.2
Added Paths:
-----------
trunk/lib/libc/gen/waitid.c
Modified: trunk/lib/libc/gen/Makefile.inc
===================================================================
--- trunk/lib/libc/gen/Makefile.inc 2015-08-14 14:20:09 UTC (rev 7247)
+++ trunk/lib/libc/gen/Makefile.inc 2015-08-14 14:39:58 UTC (rev 7248)
@@ -34,7 +34,7 @@
syslog.c telldir.c termios.c time.c times.c timezone.c tls.c \
ttyname.c ttyslot.c ualarm.c ulimit.c uname.c unvis.c \
usleep.c utime.c utxdb.c valloc.c vis.c wait.c wait3.c waitpid.c \
- wordexp.c
+ waitid.c wordexp.c
CANCELPOINTS_SRCS=sem.c sem_new.c
.for src in ${CANCELPOINTS_SRCS}
Added: trunk/lib/libc/gen/waitid.c
===================================================================
--- trunk/lib/libc/gen/waitid.c (rev 0)
+++ trunk/lib/libc/gen/waitid.c 2015-08-14 14:39:58 UTC (rev 7248)
@@ -0,0 +1,65 @@
+/*-
+ * Copyright (c) 2012 Jukka A. Ukkonen
+ * All rights reserved.
+ *
+ * This software was developed by Jukka Ukkonen for FreeBSD.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__MBSDID("$MidnightBSD$");
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stddef.h>
+#include <string.h>
+#include <signal.h>
+#include <errno.h>
+#include "un-namespace.h"
+
+int
+__waitid(idtype_t idtype, id_t id, siginfo_t *info, int flags)
+{
+ int status;
+ pid_t ret;
+
+ ret = _wait6(idtype, id, &status, flags, NULL, info);
+
+ /*
+ * According to SUSv4, waitid() shall not return a PID when a
+ * process is found, but only 0. If a process was actually
+ * found, siginfo_t fields si_signo and si_pid will be
+ * non-zero. In case WNOHANG was set in the flags and no
+ * process was found those fields are set to zero using
+ * memset() below.
+ */
+ if (ret == 0 && info != NULL)
+ memset(info, 0, sizeof(*info));
+ else if (ret > 0)
+ ret = 0;
+ return (ret);
+}
+
+__weak_reference(__waitid, waitid);
+__weak_reference(__waitid, _waitid);
Property changes on: trunk/lib/libc/gen/waitid.c
___________________________________________________________________
Added: svn:eol-style
## -0,0 +1 ##
+native
\ No newline at end of property
Added: svn:keywords
## -0,0 +1 ##
+MidnightBSD=%H
\ No newline at end of property
Added: svn:mime-type
## -0,0 +1 ##
+text/plain
\ No newline at end of property
Modified: trunk/lib/libc/include/namespace.h
===================================================================
--- trunk/lib/libc/include/namespace.h 2015-08-14 14:20:09 UTC (rev 7247)
+++ trunk/lib/libc/include/namespace.h 2015-08-14 14:39:58 UTC (rev 7248)
@@ -229,6 +229,7 @@
#define socketpair _socketpair
#define usleep _usleep
#define wait4 _wait4
+#define wait6 _wait6
#define waitpid _waitpid
#define write _write
#define writev _writev
Modified: trunk/lib/libc/include/un-namespace.h
===================================================================
--- trunk/lib/libc/include/un-namespace.h 2015-08-14 14:20:09 UTC (rev 7247)
+++ trunk/lib/libc/include/un-namespace.h 2015-08-14 14:39:58 UTC (rev 7248)
@@ -210,6 +210,7 @@
#undef socketpair
#undef usleep
#undef wait4
+#undef wait6
#undef waitpid
#undef write
#undef writev
Modified: trunk/lib/libc/sys/Makefile.inc
===================================================================
--- trunk/lib/libc/sys/Makefile.inc 2015-08-14 14:20:09 UTC (rev 7247)
+++ trunk/lib/libc/sys/Makefile.inc 2015-08-14 14:39:58 UTC (rev 7248)
@@ -210,5 +210,5 @@
MLINKS+=truncate.2 ftruncate.2
MLINKS+=unlink.2 unlinkat.2
MLINKS+=utimes.2 futimes.2 utimes.2 futimesat.2 utimes.2 lutimes.2
-MLINKS+=wait.2 wait3.2 wait.2 wait4.2 wait.2 waitpid.2
+MLINKS+=wait.2 wait3.2 wait.2 wait4.2 wait.2 waitpid.2 wait.2 wait6.2
MLINKS+=write.2 pwrite.2 write.2 pwritev.2 write.2 writev.2
Modified: trunk/lib/libc/sys/Symbol.map
===================================================================
--- trunk/lib/libc/sys/Symbol.map 2015-08-14 14:20:09 UTC (rev 7247)
+++ trunk/lib/libc/sys/Symbol.map 2015-08-14 14:39:58 UTC (rev 7248)
@@ -380,6 +380,7 @@
FBSD_1.3 {
posix_fadvise;
+ wait6;
};
FBSDprivate_1.0 {
@@ -1013,6 +1014,8 @@
__sys_vadvise;
_wait4;
__sys_wait4;
+ _wait6;
+ __sys_wait6;
_write;
__sys_write;
_writev;
Modified: trunk/lib/libc/sys/wait.2
===================================================================
--- trunk/lib/libc/sys/wait.2 2015-08-14 14:20:09 UTC (rev 7247)
+++ trunk/lib/libc/sys/wait.2 2015-08-14 14:39:58 UTC (rev 7248)
@@ -28,15 +28,17 @@
.\" @(#)wait.2 8.2 (Berkeley) 4/19/94
.\" $MidnightBSD$
.\"
-.Dd November 12, 2005
+.Dd November 10, 2012
.Dt WAIT 2
.Os
.Sh NAME
.Nm wait ,
+.Nm waitid ,
.Nm waitpid ,
+.Nm wait3 ,
.Nm wait4 ,
-.Nm wait3
-.Nd wait for process termination
+.Nm wait6
+.Nd wait for processes to change status
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
@@ -46,6 +48,9 @@
.Fn wait "int *status"
.Ft pid_t
.Fn waitpid "pid_t wpid" "int *status" "int options"
+.In sys/signal.h
+.Ft int
+.Fn waitid "idtype_t idtype" "id_t id" "siginfo_t *info" "int options"
.In sys/time.h
.In sys/resource.h
.Ft pid_t
@@ -52,6 +57,8 @@
.Fn wait3 "int *status" "int options" "struct rusage *rusage"
.Ft pid_t
.Fn wait4 "pid_t wpid" "int *status" "int options" "struct rusage *rusage"
+.Ft pid_t
+.Fn wait6 "idtype_t idtype" "id_t id" "int *status" "int options" "struct __wrusage *wrusage" "siginfo_t *infop"
.Sh DESCRIPTION
The
.Fn wait
@@ -86,28 +93,172 @@
that need to wait for certain child processes,
that need resource utilization statistics accumulated by child processes,
or that require options.
-The other wait functions are implemented using
-.Fn wait4 .
.Pp
+The broadest interface of all functions in this family is
+.Fn wait6
+which is otherwise very much like
+.Fn wait4
+but with a few very important distinctions.
+To wait for exited processes, the option flag
+.Dv WEXITED
+need to be explicitly specified.
+This allows for waiting for processes which have experienced other
+status changes without having to handle also the exit status from
+the terminated processes.
+Instead of the traditional
+.Dv rusage
+argument, a pointer to a new structure
+.Bd -literal
+struct __wrusage {
+ struct rusage wru_self;
+ struct rusage wru_children;
+};
+.Ed
+can be passed.
+This allows the calling process to collect resource usage statistics
+from both its own child process as well as from its grand children.
+When no resource usage statistics are needed this pointer can be
+.Dv NULL .
+The last argument
+.Fa infop
+must be either
+.Dv NULL
+or a pointer to a
+.Fa siginfo_t
+structure.
+When specified, the structure is filled the same as for
+.Dv SIGNCHLD
+signal, delivered at the process state change.
+.br
+The process, which state is queried, is specified by two arguments
+.Fa idtype
+and
+.Fa id .
+The separate
+.Fa idtype
+and
+.Fa id
+arguments allows to support many other types of
+IDs as well in addition to PID and PGID.
+.Bl -bullet -offset indent
+.It
+If
+.Fa idtype
+is
+.Dv P_PID ,
+.Fn waitid
+and
+.Fn wait6
+wait for the child process with a process ID equal to
+.Dv (pid_t)id .
+.It
+If
+.Fa idtype
+is
+.Dv P_PGID ,
+.Fn waitid
+and
+.Fn wait6
+wait for the child process with a process group ID equal to
+.Dv (pid_t)id .
+.It
+If
+.Fa idtype
+is
+.Dv P_ALL ,
+.Fn waitid
+and
+.Fn wait6
+wait for any child process and the
+.Dv id
+is ignored.
+.It
+If
+.Fa idtype
+is
+.Dv P_PID
+or
+.Dv P_PGID
+and the
+.Dv id
+is zero,
+.Fn waitid
+and
+.Fn wait6
+wait for any child process in the same process group as the caller.
+.El
+.Pp
+Non-standard specifiers for the process to wait for, supported by this
+implementation of
+.Fn waitid
+and
+.Fn wait6 ,
+are:
+.Bl -bullet -offset indent
+.It
The
+.Fa idtype
+value
+.Dv P_UID
+waits for processes which effective UID is equal to
+.Dv (uid_t)id .
+.It
+The
+.Fa idtype
+value
+.Dv P_GID
+waits for processes which effective GID is equal to
+.Dv (gid_t)id .
+.It
+The
+.Fa idtype
+value
+.Dv P_SID
+waits for processes which session ID is equal to
+.Dv id .
+In case the child process started its own new session,
+SID will be the same as its own PID.
+Otherwise the SID of a child process will match the caller's SID.
+.It
+The
+.Fa idtype
+value
+.Dv P_JAILID
+waits for processes within a jail which jail identifier is equal
+to
+.Dv id .
+.El
+.Pp
+For
+.Fn wait ,
+.Fn wait3 ,
+and
+.Fn wait4
+functions, the single
.Fa wpid
argument specifies the set of child processes for which to wait.
+.Bl -bullet -offset indent
+.It
If
.Fa wpid
is -1, the call waits for any child process.
+.It
If
.Fa wpid
is 0,
the call waits for any child process in the process group of the caller.
+.It
If
.Fa wpid
is greater than zero, the call waits for the process with process id
.Fa wpid .
+.It
If
.Fa wpid
is less than -1, the call waits for any process whose process group id
equals the absolute value of
.Fa wpid .
+.El
.Pp
The
.Fa status
@@ -116,42 +267,103 @@
The
.Fa options
argument contains the bitwise OR of any of the following options.
-The
-.Dv WCONTINUED
-option indicates that children of the current process that
+.Bl -tag -width Ds
+.It Dv WCONTINUED
+indicates that children of the current process that
have continued from a job control stop, by receiving a
.Dv SIGCONT
signal, should also have their status reported.
-The
-.Dv WNOHANG
-option
-is used to indicate that the call should not block if
-there are no processes that wish to report status.
-If the
-.Dv WUNTRACED
-option is set,
-children of the current process that are stopped
+.It Dv WNOHANG
+is used to indicate that the call should not block when
+there are no processes wishing to report status.
+.It Dv WUNTRACED
+indicates that children of the current process which are stopped
due to a
.Dv SIGTTIN , SIGTTOU , SIGTSTP ,
or
.Dv SIGSTOP
-signal also have their status reported.
-The
-.Dv WSTOPPED
-option is an alias for
+signal shall have their status reported.
+.It Dv WSTOPPED
+is an alias for
.Dv WUNTRACED .
-The
-.Dv WNOWAIT
-option keeps the process whose status is returned in a waitable state.
+.It Dv WTRAPPED
+allows waiting for processes which have trapped or reached a breakpoint.
+.It Dv WEXITED
+indicates that the caller is wants to receive status reports from
+terminated processes.
+This flag is implicitly set for the functions
+.Fn wait ,
+.Fn waitpid ,
+.Fn wait3 ,
+and
+.Fn wait4 .
+.br
+For the
+.Fn waitid
+and
+.Fn wait6
+functions, the flag has to be explicitly included in the
+.Fa options ,
+if status reports from terminated processes are expected.
+.It Dv WNOWAIT
+keeps the process whose status is returned in a waitable state.
The process may be waited for again after this call completes.
+.El
+.sp
+For the
+.Fn waitid
+and
+.Fn wait6
+functions, at least one of the options
+.Dv WEXITED ,
+.Dv WUNTRACED ,
+.Dv WSTOPPED ,
+.Dv WTRAPPED ,
+or
+.Dv WCONTINUED
+must be specified.
+Otherwise there will be no events for the call to report.
+To avoid hanging indefinitely in such a case these functions
+return -1 with
+.Dv errno
+set to
+.Dv EINVAL .
.Pp
If
.Fa rusage
-is non-zero, a summary of the resources used by the terminated
-process and all its
-children is returned (this information is currently not available
-for stopped or continued processes).
+is non-NULL, a summary of the resources used by the terminated
+process and all its children is returned.
.Pp
+If
+.Fa wrusage
+argument is non-NULL, a resource usage statistics
+from both its own child process as well as from its grand children
+is returned.
+.Pp
+If
+.Fa infop
+is non-NULL, it must point to a
+.Dv siginfo_t
+structure which is filled on return such that the
+.Dv si_signo
+field is always
+.Dv SIGCHLD
+and the field
+.Dv si_pid
+if be non-zero, if there is a status change to report.
+If there are no status changes to report and WNOHANG is applied,
+both of these fields are returned zero.
+When using the
+.Fn waitid
+function with the
+.Dv WNOHANG
+option set, checking these fields is the only way to know whether
+there were any status changes to report, because the return value
+from
+.Fn waitid
+is be zero as it is for any successful return from
+.Fn waitid .
+.Pp
When the
.Dv WNOHANG
option is specified and no processes
@@ -175,9 +387,23 @@
with a
.Fa wpid
value of -1.
+The
+.Fn wait6
+call, with the bits
+.Dv WEXITED
+and
+.Dv WTRAPPED
+set in the
+.Fa options
+and with
+.Fa infop
+set to
+.Dv NULL ,
+is similar to
+.Fn wait4 .
.Pp
The following macros may be used to test the manner of exit of the process.
-One of the first three macros will evaluate to a non-zero (true) value:
+One of the first four macros will evaluate to a non-zero (true) value:
.Bl -tag -width Ds
.It Fn WIFCONTINUED status
True if the process has not terminated, and
@@ -284,6 +510,7 @@
is set to indicate the error.
.Pp
If
+.Fn wait6 ,
.Fn wait4 ,
.Fn wait3 ,
or
@@ -306,6 +533,18 @@
is returned and
.Va errno
is set to indicate the error.
+.Pp
+If
+.Fn waitid
+returns because one or more processes have a state change to report,
+0 is returned.
+To indicate an error, -1 will be returned and
+.Dv errno
+set to an appropriate value.
+If
+.Dv WNOHANG
+was used, 0 can be returned indicating no error, but no processes
+may have changed state either, if si_signo and/or si_pid are zero.
.Sh ERRORS
The
.Fn wait
@@ -335,6 +574,14 @@
or the signal did not have the
.Dv SA_RESTART
flag set.
+.It Bq Er EINVAL
+An invalid value was specified for
+.Fa options ,
+or
+.Fa idtype
+and
+.Fa id
+do not specify a valid set of processes.
.El
.Sh SEE ALSO
.Xr _exit 2 ,
@@ -344,11 +591,13 @@
.Xr siginfo 3
.Sh STANDARDS
The
-.Fn wait
+.Fn wait ,
+.Fn waitpid ,
and
-.Fn waitpid
+.Fn waitid
functions are defined by POSIX;
-.Fn wait4
+.Fn wait6 ,
+.Fn wait4 ,
and
.Fn wait3
are not specified by POSIX.
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