Date: Fri, 6 Nov 2009 23:24:46 +0100 From: Jilles Tjoelker <jilles@stack.nl> To: freebsd-hackers@freebsd.org Subject: [patch] add pwait utility Message-ID: <20091106222446.GB60707@stack.nl>
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I propose adding a small new utility to /usr/bin: pwait. Similar to the
Solaris utility of the same name, it waits for any process to terminate.
Some use cases I have in mind:
* rc.subr's wait_for_pids. This is a cleaner and more efficient fix for
PR conf/132766. In the rare case that /usr is not available, the old
sleep(1) method can be used.
* interactive use, e.g. to shut down the computer when some task is done
even if the task is already running
--
Jilles Tjoelker
--5vNYLRcllDrimb99
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Index: usr.bin/pwait/pwait.1
===================================================================
--- usr.bin/pwait/pwait.1 (revision 0)
+++ usr.bin/pwait/pwait.1 (revision 0)
@@ -0,0 +1,78 @@
+.\"
+.\" Copyright (c) 2004-2009, Jilles Tjoelker
+.\" 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.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+.\" COPYRIGHT OWNER 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.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 1, 2009
+.Os
+.Dt PWAIT 1
+.Sh NAME
+.Nm pwait
+.Nd wait for processes to terminate
+.Sh SYNOPSIS
+.Nm
+.Op Fl v
+.Ar pid
+\&...
+.Sh DESCRIPTION
+The
+.Nm
+utility will wait until each of the given processes has terminated.
+.Pp
+The following option is available:
+.Bl -tag -width indent
+.It Fl v
+Print the exit status when each process terminates.
+.El
+.Sh DIAGNOSTICS
+.Pp
+The
+.Nm
+utility returns 0 on success, and >0 if an error occurs.
+.Pp
+Invalid pids elicit a warning message but are otherwise ignored.
+.Sh SEE ALSO
+.Xr kill 1 ,
+.Xr pkill 1 ,
+.Xr ps 1 ,
+.Xr wait 1 ,
+.Xr kqueue 2
+.Sh NOTES
+.Nm
+is not a substitute for the
+.Xr wait 1
+builtin
+as it will not clean up any zombies or state in the parent process.
+.Sh HISTORY
+A
+.Nm
+command first appeared in SunOS 5.8.
Property changes on: usr.bin/pwait/pwait.1
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Added: svn:mime-type
+ text/plain
Added: svn:keywords
+ FreeBSD=%H
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+ native
Index: usr.bin/pwait/pwait.c
===================================================================
--- usr.bin/pwait/pwait.c (revision 0)
+++ usr.bin/pwait/pwait.c (revision 0)
@@ -0,0 +1,148 @@
+/*-
+ * Copyright (c) 2004-2009, Jilles Tjoelker
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static void
+usage(void)
+{
+
+ fprintf(stderr, "usage: pwait [-v] pid ...\n");
+ exit(EX_USAGE);
+}
+
+/*
+ * pwait - wait for processes to terminate
+ */
+int
+main(int argc, char *argv[])
+{
+ int kq;
+ struct kevent *e;
+ int verbose = 0;
+ int opt, nleft, n, i, duplicate, status;
+ long pid;
+ char *s, *end;
+
+ while ((opt = getopt(argc, argv, "v")) != -1) {
+ switch (opt) {
+ case 'v':
+ verbose = 1;
+ break;
+ default:
+ usage();
+ /* NOTREACHED */
+ }
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if (argc == 0)
+ usage();
+
+ kq = kqueue();
+ if (kq == -1)
+ err(1, "kqueue");
+
+ e = malloc(argc * sizeof(struct kevent));
+ if (e == NULL)
+ err(1, "malloc");
+ nleft = 0;
+ for (n = 0; n < argc; n++) {
+ s = argv[n];
+ if (!strncmp(s, "/proc/", 6)) /* Undocumented Solaris compat */
+ s += 6;
+ errno = 0;
+ pid = strtol(s, &end, 10);
+ if (pid < 0 || *end != '\0' || errno != 0) {
+ warnx("%s: bad process id", s);
+ continue;
+ }
+ duplicate = 0;
+ for (i = 0; i < nleft; i++)
+ if (e[i].ident == (uintptr_t)pid)
+ duplicate = 1;
+ if (!duplicate) {
+ EV_SET(e + nleft, pid, EVFILT_PROC, EV_ADD, NOTE_EXIT,
+ 0, NULL);
+ if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
+ warn("%ld", pid);
+ else
+ nleft++;
+ }
+ }
+
+ if (nleft == 0)
+ exit(0); /* Solaris does this too. */
+
+ while (nleft > 0) {
+ n = kevent(kq, NULL, 0, e, nleft, NULL);
+ if (n == -1)
+ err(1, "kevent");
+ if (verbose)
+ for (i = 0; i < n; i++) {
+ status = e[i].data;
+ if (WIFEXITED(status))
+ printf("%ld: exited with status %d.\n",
+ (long)e[i].ident,
+ WEXITSTATUS(status));
+ else if (WIFSIGNALED(status))
+ printf("%ld: killed by signal %d.\n",
+ (long)e[i].ident,
+ WTERMSIG(status));
+ else
+ printf("%ld: terminated.\n",
+ (long)e[i].ident);
+ }
+ nleft -= n;
+ }
+
+ return 0;
+}
Property changes on: usr.bin/pwait/pwait.c
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Added: svn:mime-type
+ text/plain
Added: svn:keywords
+ FreeBSD=%H
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+ native
Index: usr.bin/pwait/Makefile
===================================================================
--- usr.bin/pwait/Makefile (revision 0)
+++ usr.bin/pwait/Makefile (revision 0)
@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+PROG= pwait
+
+WARNS?= 6
+
+.include <bsd.prog.mk>
Property changes on: usr.bin/pwait/Makefile
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+ text/plain
Added: svn:keywords
+ FreeBSD=%H
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Index: usr.bin/Makefile
===================================================================
--- usr.bin/Makefile (revision 198703)
+++ usr.bin/Makefile (working copy)
@@ -154,6 +154,7 @@
printenv \
printf \
procstat \
+ pwait \
${_quota} \
renice \
rev \
--5vNYLRcllDrimb99--
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