[RFC] Process Events Connector (test program)

Matthew Helsley
2005-09-29T02:53:34Z

The following test program can be used to print the process events
received via the proposed connector.

Cheers,
-Matt Helsley < matthltc at us.ibm.com >

---

/*
* test process event connector - test_cn_proc.c
*
* Listens for process events (fork, exec, change uid/gid/..., and exit)
* received through a kernel connector and prints them.
*
* 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
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/socket.h>
#include <sys/types.h>

#include <linux/connector.h>
#include <linux/netlink.h>
#include "linux/cn_proc.h"

#include <signal.h>
#include <setjmp.h>

#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 max(x,y) ((y)<(x)?(x):(y))
#define min(x,y) ((y)>(x)?(x):(y))

#define BUFF_SIZE (max(max(SEND_MESSAGE_SIZE, RECV_MESSAGE_SIZE), 1024))
#define MIN_RECV_SIZE (min(SEND_MESSAGE_SIZE, RECV_MESSAGE_SIZE))

#define PROC_CN_MCAST_LISTEN (1)
#define PROC_CN_MCAST_IGNORE (2)

/*
* SIGINT causes the program to exit gracefully
* this could happen any time after the LISTEN message has
* been sent
*/
#define INTR_SIG SIGINT
sigjmp_buf g_jmp;

void handle_intr (int signum)
{
siglongjmp(g_jmp, signum);
}

void handle_msg (struct cn_msg *cn_hdr)
{
struct proc_event *ev;

/* print the message */
printf("cn seq: %d\ncn ack: %d\n",
cn_hdr->seq, cn_hdr->ack);
ev = (struct proc_event*)cn_hdr->data;
printf("ev cpu: %d\n", ev->cpu);
switch(ev->what){
case PROC_EVENT_FORK:
printf("event: fork\n\tparent:\t%d %d\n\tchild: %d %d\n",
ev->fork.parent_pid,
ev->fork.parent_tgid,
ev->fork.child_pid,
ev->fork.child_tgid);
break;
case PROC_EVENT_EXEC:
printf("event: exec\n\tprocess:\t%d %d\n",
ev->exec.process_pid,
ev->exec.process_tgid);
break;
case PROC_EVENT_RUID:
printf("event: ruid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.uid,
ev->id.to.uid);
break;
case PROC_EVENT_RGID:
printf("event: rgid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.gid,
ev->id.to.gid);
break;
case PROC_EVENT_EUID:
printf("event: euid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.uid,
ev->id.to.uid);
break;
case PROC_EVENT_EGID:
printf("event: egid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.gid,
ev->id.to.gid);
break;
case PROC_EVENT_SUID:
printf("event: suid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.uid,
ev->id.to.uid);
break;
case PROC_EVENT_SGID:
printf("event: sgid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.gid,
ev->id.to.gid);
break;
case PROC_EVENT_FSUID:
printf("event: fsuid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.uid,
ev->id.to.uid);
break;
case PROC_EVENT_FSGID:
printf("event: fsgid\n\tprocess:\t%d %d\n\t%d -> %d\n",
ev->id.process_pid,
ev->id.process_tgid,
ev->id.from.gid,
ev->id.to.gid);
break;
case PROC_EVENT_EXIT:
printf("event: exit\n\tprocess:\t%d %d\n\texit code:\t%d\n",
ev->exit.process_pid,
ev->exit.process_tgid,
ev->exit.exit_code);
break;
default:
printf("event <unknown>\n");
break;
}
}

int main(int argc, char **argv)
{
int sk_nl;
int err;
struct sockaddr_nl my_nla, kern_nla, from_nla;
socklen_t from_nla_len;
char buff[BUFF_SIZE];
int rc = -1;
struct nlmsghdr *nl_hdr;
struct cn_msg *cn_hdr;
enum proc_cn_mcast_op *mcop_msg;
size_t recv_len = 0;

if (getuid() != 0) {
printf("Only root can start/stop the fork connector\n");
return 0;
}

if (argc != 1)
return 0;

/*
* Create an endpoint for communication. Use the kernel user
* interface device (PF_NETLINK) which is a datagram oriented
* service (SOCK_DGRAM). The protocol used is the connector
* protocol (NETLINK_CONNECTOR)
*/
sk_nl = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
if (sk_nl == -1) {
printf("socket sk_nl error");
return rc;
}

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;

err = bind(sk_nl, (struct sockaddr *)&my_nla, sizeof(my_nla));
if (err == -1) {
printf("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];
if (sigsetjmp(g_jmp, INTR_SIG) != 0) {
printf("sending proc connector: PROC_CN_MCAST_IGNORE... ");
memset(buff, 0, sizeof(buff));
*mcop_msg = PROC_CN_MCAST_IGNORE;
} else {
printf("sending proc connector: PROC_CN_MCAST_LISTEN... ");
memset(buff, 0, sizeof(buff));
*mcop_msg = PROC_CN_MCAST_LISTEN;
signal(INTR_SIG, handle_intr);
}

/* fill the netlink header */
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();

/* fill the connector header */
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) {
printf("failed to send proc connector mcast ctl op!\n");
goto close_and_exit;
}
printf("sent\n");

if (*mcop_msg == PROC_CN_MCAST_IGNORE) {
rc = 0;
goto close_and_exit;
}

printf("Reading process events from proc connector.\n"
"Hit Ctrl-C to exit\n");
for(memset(buff, 0, sizeof(buff)), from_nla_len = sizeof(from_nla);
; memset(buff, 0, sizeof(buff)), from_nla_len = sizeof(from_nla)) {
struct nlmsghdr *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 (recv_len < 1)
continue;
while (NLMSG_OK(nlh, recv_len)) {
cn_hdr = NLMSG_DATA(nlh);
if (nlh->nlmsg_type == NLMSG_NOOP)
continue;
if ((nlh->nlmsg_type == NLMSG_ERROR) ||
(nlh->nlmsg_type == NLMSG_OVERRUN))
break;
handle_msg(cn_hdr);
if (nlh->nlmsg_type == NLMSG_DONE)
break;
nlh = NLMSG_NEXT(nlh, recv_len);
}
}

close_and_exit:
close(sk_nl);
exit(rc);

return 0;
}