add pwait(1)

2 files changed, 286 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index 9ea1ede..297ce12 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,9 @@
 CFLAGS=-Wall -pedantic -ansi
 
-all: extrace
+all: extrace pwait
 
 cap: extrace
-	sudo setcap cap_net_admin+ep extrace
+	sudo setcap cap_net_admin+ep extrace cap_net_admin+ep pwait
 
 clean:
-	rm -f extrace
+	rm -f extrace pwait
diff --git a/pwait.c b/pwait.c
new file mode 100644
index 0000000..21e4077
--- /dev/null
+++ b/pwait.c
@@ -0,0 +1,283 @@
+/* pwait - wait for processes to terminate
+ *
+ * Requires CONFIG_CONNECTOR=y and CONFIG_PROC_EVENTS=y.
+ * Requires root or "setcap cap_net_admin+ep pwait".
+ *
+ * Usage: pwait [-v] PID...
+ * -v  Print the exit status when each process terminates.
+ *
+ * Copyright (C) 2014 Christian Neukirchen <chneukirchen@gmail.com>
+ *
+ * hacked from sources of:
+ */
+/* FreeBSD: head/bin/pwait/pwait.c 245506 2013-01-16 18:15:25Z delphij */
+/*-
+ * 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.
+ */
+/* exec-notify, so you can watch your acrobat reader or vim executing "bash -c"
+ * commands ;-)
+ * Requires some 2.6.x Linux kernel with proc connector enabled.
+ *
+ * $  cc -Wall -ansi -pedantic -std=c99 exec-notify.c
+ *
+ * (C) 2007-2010 Sebastian Krahmer <krahmer@suse.de> original netlink handling
+ * stolen from an proc-connector example, copyright folows:
+ */
+/* Copyright (C) Matt Helsley, IBM Corp. 2005
+ * Derived from fcctl.c by Guillaume Thouvenin
+ * Original copyright notice follows:
+ *
+ * Copyright (C) 2005 BULL SA.
+ * Written by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#define _XOPEN_SOURCE 700
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <linux/connector.h>
+#include <linux/netlink.h>
+#include <linux/cn_proc.h>
+
+#define max(x,y) ((y)<(x)?(x):(y))
+#define min(x,y) ((y)>(x)?(x):(y))
+
+#define SEND_MESSAGE_LEN (NLMSG_LENGTH(sizeof (struct cn_msg) + \
+				       sizeof (enum proc_cn_mcast_op)))
+#define RECV_MESSAGE_LEN (NLMSG_LENGTH(sizeof (struct cn_msg) + \
+				       sizeof (struct proc_event)))
+
+#define SEND_MESSAGE_SIZE    (NLMSG_SPACE(SEND_MESSAGE_LEN))
+#define RECV_MESSAGE_SIZE    (NLMSG_SPACE(RECV_MESSAGE_LEN))
+
+#define BUFF_SIZE (max(max(SEND_MESSAGE_SIZE, RECV_MESSAGE_SIZE), 1024))
+#define MIN_RECV_SIZE (min(SEND_MESSAGE_SIZE, RECV_MESSAGE_SIZE))
+
+sig_atomic_t quit = 0;
+
+static void
+sigint(int sig)
+{
+	quit = 1;
+}
+
+static void
+display(pid_t pid, int status)
+{
+	if (WIFEXITED(status))
+		printf("%ld: exited with status %d.\n",
+		    (long)pid,
+		    WEXITSTATUS(status));
+	else if (WIFSIGNALED(status))
+		printf("%ld: killed by signal %d.\n",
+		    (long)pid,
+		    WTERMSIG(status));
+	else
+		printf("%ld: terminated.\n",
+		    (long)pid);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int sk_nl;
+	struct sockaddr_nl my_nla, kern_nla, from_nla;
+	socklen_t from_nla_len;
+	char buff[BUFF_SIZE];
+	struct nlmsghdr *nl_hdr, *nlh;
+	struct cn_msg *cn_hdr;
+	struct proc_event *ev;
+	enum proc_cn_mcast_op *mcop_msg;
+	size_t recv_len = 0;
+	int opt;
+	int n;
+	pid_t *pids;
+	pid_t pid;
+	char *end;
+	int verbose = 0;
+	int seen = 0;
+	int rc = -1;
+
+	while ((opt = getopt(argc, argv, "+v")) != -1)
+		switch (opt) {
+		case 'v': verbose = 1; break;
+		default: goto usage;
+		}
+	
+	argc -= optind;
+	argv += optind;
+
+	if (argc == 0) {
+usage:
+		fprintf(stderr, "Usage: pwait [-v] PID...\n");
+		exit(1);
+	}
+
+	pids = calloc(argc, sizeof (pid_t));
+	if (!pids) {
+		perror("calloc");
+		exit(1);
+	}
+
+	for (n = 0; n < argc; n++) {
+		errno = 0;
+		pid = strtol(argv[n], &end, 10);
+		if (pid < 0 || *end != '\0' || errno != 0) {
+			fprintf(stderr, "%s: bad process id\n", argv[n]);
+			continue;
+		}
+		pids[n] = pid;
+	}
+
+	sk_nl = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+	if (sk_nl == -1) {
+		perror("socket sk_nl error");
+		exit(1);
+	}
+
+	my_nla.nl_family = AF_NETLINK;
+	my_nla.nl_groups = CN_IDX_PROC;
+	my_nla.nl_pid = getpid();
+
+	kern_nla.nl_family = AF_NETLINK;
+	kern_nla.nl_groups = CN_IDX_PROC;
+	kern_nla.nl_pid = 1;
+
+	if (bind(sk_nl, (struct sockaddr *)&my_nla, sizeof my_nla) == -1) {
+		perror("binding sk_nl error");
+		goto close_and_exit;
+	}
+	nl_hdr = (struct nlmsghdr *)buff;
+	cn_hdr = (struct cn_msg *)NLMSG_DATA(nl_hdr);
+	mcop_msg = (enum proc_cn_mcast_op*)&cn_hdr->data[0];
+
+	memset(buff, 0, sizeof buff);
+	*mcop_msg = PROC_CN_MCAST_LISTEN;
+
+	nl_hdr->nlmsg_len = SEND_MESSAGE_LEN;
+	nl_hdr->nlmsg_type = NLMSG_DONE;
+	nl_hdr->nlmsg_flags = 0;
+	nl_hdr->nlmsg_seq = 0;
+	nl_hdr->nlmsg_pid = getpid();
+
+	cn_hdr->id.idx = CN_IDX_PROC;
+	cn_hdr->id.val = CN_VAL_PROC;
+	cn_hdr->seq = 0;
+	cn_hdr->ack = 0;
+	cn_hdr->len = sizeof (enum proc_cn_mcast_op);
+
+	if (send(sk_nl, nl_hdr, nl_hdr->nlmsg_len, 0) != nl_hdr->nlmsg_len) {
+		fprintf(stderr, "failed to send proc connector mcast ctl op!\n");
+		goto close_and_exit;
+	}
+
+	if (*mcop_msg == PROC_CN_MCAST_IGNORE)
+		goto close_and_exit;
+
+	signal(SIGINT, sigint);
+
+	rc = 0;
+	while (!quit) {
+		memset(buff, 0, sizeof buff);
+
+		from_nla_len = sizeof from_nla;
+		nlh = (struct nlmsghdr *)buff;
+		memcpy(&from_nla, &kern_nla, sizeof from_nla);
+		recv_len = recvfrom(sk_nl, buff, BUFF_SIZE, 0,
+		    (struct sockaddr *)&from_nla, &from_nla_len);
+		if (from_nla.nl_pid != 0 || recv_len < 1)
+			continue;
+
+		while (NLMSG_OK(nlh, recv_len)) {
+			if (nlh->nlmsg_type == NLMSG_NOOP)
+				continue;
+			if (nlh->nlmsg_type == NLMSG_ERROR ||
+			    nlh->nlmsg_type == NLMSG_OVERRUN)
+				break;
+			
+			ev = (struct proc_event *)
+			    ((struct cn_msg *) NLMSG_DATA(nlh))->data;
+			
+			if (ev->what == PROC_EVENT_EXIT) {
+				int status = ev->event_data.exit.exit_code;
+				pid_t pid = ev->event_data.exit.process_pid;
+				
+				seen = 0;
+				for (n = 0; n < argc; n++)
+					if (pids[n] == pid) {
+						if (verbose && !seen)
+							display(pid, status);
+						pids[n] = 0;
+						seen = 1;
+					}
+			}
+			
+			if (nlh->nlmsg_type == NLMSG_DONE)
+				break;
+			nlh = NLMSG_NEXT(nlh, recv_len);
+		}
+		
+		quit = 1;
+		for (n = 0; n < argc; n++)
+			if (pids[n] != 0)
+				quit = 0;
+	}
+
+close_and_exit:
+	close(sk_nl);
+	return rc;
+}