rfork/minherit glue in libc

man pages adapted from OpenBSD's versions.

4 files changed, 237 insertions, 7 deletions

diff --git a/lib/libc/i386/sys/rfork.S b/lib/libc/i386/sys/rfork.S
new file mode 100644
index 0000000..189d399
--- /dev/null
+++ b/lib/libc/i386/sys/rfork.S
@@ -0,0 +1,51 @@
+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * William Jolitz.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ *
+ *	$Id$
+ */
+
+#if defined(SYSLIBC_RCS) && !defined(lint)
+	.text
+	.asciz "$Id$"
+#endif /* SYSLIBC_RCS and not lint */
+
+#include "SYS.h"
+
+PSYSCALL(rfork)
+	cmpl	$0,%edx	/* parent, since %edx == 0 in parent, 1 in child */
+	je	1f
+	movl	$0,%eax
+1:
+	ret		/* pid = rfork(); */
diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index f115d3d..44534cd 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -5,7 +5,7 @@
 
 # modules with non-default implementations on at least one architecture:
 SRCS+=	Ovfork.S brk.S cerror.S exect.S fork.S pipe.S ptrace.S reboot.S \
-	sbrk.S setlogin.S sigpending.S sigprocmask.S sigreturn.S \
+	rfork.S sbrk.S setlogin.S sigpending.S sigprocmask.S sigreturn.S \
 	sigsuspend.S syscall.S
 
 # glue to provide compatibility between GCC 1.X and 2.X
@@ -21,11 +21,13 @@ ASM=	accept.o access.o acct.o adjtime.o bind.o chdir.o chflags.o chmod.o \
 	getrlimit.o getrusage.o getsockname.o getsockopt.o gettimeofday.o \
 	getuid.o ioctl.o kill.o ktrace.o lfs_bmapv.o lfs_markv.o \
 	lfs_segclean.o lfs_segwait.o link.o listen.o lstat.o \
-	madvise.o mincore.o mkdir.o mkfifo.o mknod.o mlock.o mount.o \
+	madvise.o mincore.o minherit.o mkdir.o mkfifo.o mknod.o mlock.o \
+	mount.o \
 	mprotect.o msgsys.o msync.o munlock.o munmap.o nfssvc.o \
 	ntp_adjtime.o open.o pathconf.o profil.o quotactl.o read.o \
 	readlink.o readv.o recvfrom.o recvmsg.o rename.o revoke.o rmdir.o \
-	rtprio.o select.o semsys.o sendmsg.o sendto.o setegid.o seteuid.o setgid.o \
+	rtprio.o select.o semsys.o sendmsg.o sendto.o setegid.o seteuid.o \
+	setgid.o \
 	setgroups.o setitimer.o	setpgid.o setpriority.o	\
 	setregid.o setreuid.o setrlimit.o \
 	setsid.o setsockopt.o settimeofday.o setuid.o shmsys.o shutdown.o \
@@ -93,8 +95,8 @@ MAN2+=	sys/accept.2 sys/access.2 sys/acct.2 sys/adjtime.2 sys/bind.2 \
 	sys/mmap.2 sys/mount.2 sys/mprotect.2 sys/msync.2 sys/munmap.2 \
 	sys/ptrace.2 sys/nfssvc.2 sys/open.2 sys/pathconf.2 sys/pipe.2 \
 	sys/profil.2 sys/quotactl.2 sys/read.2 sys/readlink.2 sys/reboot.2 \
-	sys/recv.2 sys/rename.2 sys/revoke.2 sys/rmdir.2 sys/rtprio.2 \
-	sys/select.2 \
+	sys/recv.2 sys/rename.2 sys/revoke.2 sys/rfork.2 sys/rmdir.2 \
+	sys/rtprio.2 sys/select.2 \
 	sys/semctl.2 sys/semget.2 sys/semop.2 \
 	sys/send.2 sys/setgroups.2 \
 	sys/setpgid.2 sys/setregid.2 sys/setreuid.2 \
@@ -106,8 +108,6 @@ MAN2+=	sys/accept.2 sys/access.2 sys/acct.2 sys/adjtime.2 sys/bind.2 \
 	sys/sync.2 sys/syscall.2 sys/truncate.2 sys/umask.2 sys/unlink.2 \
 	sys/utimes.2 sys/vfork.2 sys/wait.2 sys/write.2
 
-# missing: ptrace.2
-
 MLINKS+=brk.2 sbrk.2
 MLINKS+=dup.2 dup2.2
 MLINKS+=chdir.2 fchdir.2
diff --git a/lib/libc/sys/minherit.2 b/lib/libc/sys/minherit.2
new file mode 100644
index 0000000..cc26fa6
--- /dev/null
+++ b/lib/libc/sys/minherit.2
@@ -0,0 +1,67 @@
+.\"	$Id$
+.\"
+.\" Copyright (c) 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" 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.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"	This product includes software developed by the University of
+.\"	California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+.\"
+.\"	@(#)minherit.2	8.1 (Berkeley) 6/9/93
+.\"
+.Dd Feb 17, 1996
+.Dt MINHERIT 2
+.Os
+.Sh NAME
+.Nm minherit
+.Nd control the inheritance of pages
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/mman.h>
+.Ft int
+.Fn minherit "caddr_t addr" "size_t len" "int inherit"
+.Sh DESCRIPTION
+The
+.Fn minherit
+system call
+changes the specified pages to have the inheritance characteristic
+.Fa inherit .
+Not all implementations will guarantee that the inheritance characteristic
+can be set on a page basis;
+the granularity of changes may be as large as an entire region.
+.Sh SEE ALSO
+.Xr fork 2 ,
+.Xr madvise 2 , 
+.Xr mincore 2 , 
+.Xr mprotect 2 , 
+.Xr msync 2 ,
+.Xr munmap 2 ,
+.Xr rfork 2
+.Sh HISTORY
+The
+.Fn minherit
+function first appeared in OpenBSD.
diff --git a/lib/libc/sys/rfork.2 b/lib/libc/sys/rfork.2
new file mode 100644
index 0000000..6158f51
--- /dev/null
+++ b/lib/libc/sys/rfork.2
@@ -0,0 +1,112 @@
+.\"
+.\" This manual page is taken directly from Plan9, and modified to
+.\" describe the actual BSD implementation. Permission for
+.\" use of this page comes from Rob Pike <rob@plan9.att.com>.
+.\"
+.Dd Jan 12, 1996
+.Dt RFORK 2
+.Os
+.Sh NAME
+.Nm rfork
+.Nd manipulate process resources
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft int
+.Fn rfork "int flags"
+.Sh DESCRIPTION
+Forking, vforking or rforking is the only way new processes are created.
+The
+.Fa flags
+argument to
+.Fn rfork
+selects which resources of the
+invoking process (parent) are shared
+by the new process (child) or initialized to
+their default values.
+The resources include
+the open file descriptor table (which, when shared, permits processes
+to open and close files for other processes),
+and open files.
+.Fa Flags
+is the logical OR of some subset of
+.Bl -tag -width "RFCNAMEG" -compact -offset indent
+.It RFPROC
+If set a new process is created; otherwise changes affect the
+current process.
+The current implementation requires this flag to always be set.
+.It RFNOWAIT
+If set, the child process will be dissociated from the parent. Upon
+exit the child will not leave a status for the parent to collect.
+See 
+.Xr wait 2 .
+This is not currently implemented.
+.It RFNAMEG, RFCNAMEG, RFENVG, RFCENVG, RFNOTEG
+These are Plan 9 specific flags, and not implemented.
+.It RFFDG
+If set, the invoker's file descriptor table (see
+.Xr intro 2
+) is copied; otherwise the two processes share a
+single table.
+.It RFCFDG
+If set, the new process starts with a clean file descriptor table.
+Is mutually exclusive with
+.Dv RFFDG .
+.It RFMEM
+If set, the kernel will force sharing of the entire address space.
+The child
+will then inherit all the shared segments the parent process owns. Other segment
+types will be unaffected.  Subsequent forks by the parent will then
+propagate the shared data and bss between children.  The stack segment
+is always split.  May be set only with
+.Dv RFPROC .
+.El
+.Pp
+File descriptors in a shared file descriptor table are kept
+open until either they are explicitly closed
+or all processes sharing the table exit.
+.Pp
+If
+.Dv RFPROC
+is set, the
+value returned in the parent process
+is the process id
+of the child process; the value returned in the child is zero.
+Without
+.Dv RFPROC ,
+the return value is zero.
+Process id's range from 1 to the maximum integer
+.Ft ( int )
+value.
+.Fn Rfork
+will sleep, if necessary, until required process resources are available.
+.Pp
+.Fn Fork
+can be implemented as a call to
+.Xr rfork "RFFDG|RFPROC"
+but isn't for backwards compatibility.
+.Sh ERRORS
+.Fn Rfork
+will fail and no child process will be created if:
+.Bl -tag -width Er
+.It Bq Er EAGAIN
+The system-imposed limit on the total
+number of processes under execution would be exceeded.
+This limit is configuration-dependent.
+.It Bq Er EAGAIN
+The system-imposed limit
+.Dv MAXUPRC
+.Pq Aq Pa sys/param.h
+on the total number of
+processes under execution by a single user would be exceeded.
+.It Bq Er ENOMEM
+There is insufficient swap space for the new process.
+.El
+.Sh SEE ALSO
+.Xr intro 2 ,
+.Xr fork 2 ,
+.Xr vfork 2 ,
+.Xr minherit 2
+.Sh HISTORY
+The
+.Fn rfork
+function first appeared in Plan9.