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Date:   Fri, 30 Jun 2023 21:43:07 -0400
From:   "Liam R. Howlett" <Liam.Howlett@Oracle.com>
To:     Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
Cc:     davem@davemloft.net, david@fries.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, zbr@ioremap.net,
        brauner@kernel.org, johannes@sipsolutions.net,
        ecree.xilinx@gmail.com, leon@kernel.org, keescook@chromium.org,
        socketcan@hartkopp.net, petrm@nvidia.com,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        akpm@linux-foundation.org
Subject: Re: [PATCH v6 6/6] connector/cn_proc: Selftest for proc connector
Message-ID: <20230701014307.fs6tb7m5pyt6huga@revolver>
References: <20230614234129.3264175-1-anjali.k.kulkarni@oracle.com>
 <20230614234129.3264175-7-anjali.k.kulkarni@oracle.com>
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* Anjali Kulkarni <anjali.k.kulkarni@oracle.com> [230614 19:41]:
> Run as ./proc_filter -f to run new filter code. Run without "-f" to run
> usual proc connector code without the new filtering code.
> 
> Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
> ---
>  tools/testing/selftests/Makefile              |   1 +
>  tools/testing/selftests/connector/Makefile    |   6 +
>  .../testing/selftests/connector/proc_filter.c | 308 ++++++++++++++++++
>  3 files changed, 315 insertions(+)
>  create mode 100644 tools/testing/selftests/connector/Makefile
>  create mode 100644 tools/testing/selftests/connector/proc_filter.c
> 
> diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
> index 90a62cf75008..7c9673951f9a 100644
> --- a/tools/testing/selftests/Makefile
> +++ b/tools/testing/selftests/Makefile
> @@ -7,6 +7,7 @@ TARGETS += breakpoints
>  TARGETS += capabilities
>  TARGETS += cgroup
>  TARGETS += clone3
> +TARGETS += connector
>  TARGETS += core
>  TARGETS += cpufreq
>  TARGETS += cpu-hotplug
> diff --git a/tools/testing/selftests/connector/Makefile b/tools/testing/selftests/connector/Makefile
> new file mode 100644
> index 000000000000..21c9f3a973a0
> --- /dev/null
> +++ b/tools/testing/selftests/connector/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0
> +CFLAGS += -Wall
> +
> +TEST_GEN_PROGS = proc_filter
> +
> +include ../lib.mk
> diff --git a/tools/testing/selftests/connector/proc_filter.c b/tools/testing/selftests/connector/proc_filter.c
> new file mode 100644
> index 000000000000..99a382ea2544
> --- /dev/null
> +++ b/tools/testing/selftests/connector/proc_filter.c
> @@ -0,0 +1,308 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <sys/types.h>
> +#include <sys/epoll.h>
> +#include <sys/socket.h>
> +#include <linux/netlink.h>
> +#include <linux/connector.h>
> +#include <linux/cn_proc.h>
> +
> +#include <stddef.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <strings.h>
> +#include <errno.h>
> +#include <signal.h>
> +#include <string.h>
> +
> +#include "../kselftest.h"
> +
> +#define NL_MESSAGE_SIZE (sizeof(struct nlmsghdr) + sizeof(struct cn_msg) + \
> +			 sizeof(struct proc_input))
> +#define NL_MESSAGE_SIZE_NF (sizeof(struct nlmsghdr) + sizeof(struct cn_msg) + \
> +			 sizeof(int))
> +
> +#define MAX_EVENTS 1
> +
> +volatile static int interrupted;
> +static int nl_sock, ret_errno, tcount;
> +static struct epoll_event evn;
> +
> +static int filter;
> +
> +#ifdef ENABLE_PRINTS
> +#define Printf printf
> +#else
> +#define Printf ksft_print_msg
> +#endif
> +
> +int send_message(void *pinp)
> +{
> +	char buff[NL_MESSAGE_SIZE];
> +	struct nlmsghdr *hdr;
> +	struct cn_msg *msg;
> +
> +	hdr = (struct nlmsghdr *)buff;
> +	if (filter)
> +		hdr->nlmsg_len = NL_MESSAGE_SIZE;
> +	else
> +		hdr->nlmsg_len = NL_MESSAGE_SIZE_NF;
> +	hdr->nlmsg_type = NLMSG_DONE;
> +	hdr->nlmsg_flags = 0;
> +	hdr->nlmsg_seq = 0;
> +	hdr->nlmsg_pid = getpid();
> +
> +	msg = (struct cn_msg *)NLMSG_DATA(hdr);
> +	msg->id.idx = CN_IDX_PROC;
> +	msg->id.val = CN_VAL_PROC;
> +	msg->seq = 0;
> +	msg->ack = 0;
> +	msg->flags = 0;
> +
> +	if (filter) {
> +		msg->len = sizeof(struct proc_input);
> +		((struct proc_input *)msg->data)->mcast_op = ((struct proc_input *)pinp)->mcast_op;
> +		((struct proc_input *)msg->data)->event_type = ((struct proc_input *)pinp)->event_type;

These lines exceed 80 characters.

> +	} else {
> +		msg->len = sizeof(int);
> +		*(int *)msg->data = *(enum proc_cn_mcast_op *)pinp;
> +	}
> +
> +	if (send(nl_sock, hdr, hdr->nlmsg_len, 0) == -1) {
> +		ret_errno = errno;
> +		perror("send failed");
> +		return -3;
> +	}
> +	return 0;
> +}
> +
> +int register_proc_netlink(int *efd, void *input)
> +{
> +	struct sockaddr_nl sa_nl;
> +	int err = 0, epoll_fd;
> +
> +	nl_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
> +
> +	if (nl_sock == -1) {
> +		ret_errno = errno;
> +		perror("socket failed");
> +		return -1;
> +	}
> +
> +	bzero(&sa_nl, sizeof(sa_nl));
> +	sa_nl.nl_family = AF_NETLINK;
> +	sa_nl.nl_groups = CN_IDX_PROC;
> +	sa_nl.nl_pid    = getpid();
> +
> +	if (bind(nl_sock, (struct sockaddr *)&sa_nl, sizeof(sa_nl)) == -1) {
> +		ret_errno = errno;
> +		perror("bind failed");
> +		return -2;
> +	}
> +
> +	epoll_fd = epoll_create1(EPOLL_CLOEXEC);
> +	if (epoll_fd < 0) {
> +		ret_errno = errno;
> +		perror("epoll_create1 failed");
> +		return -2;
> +	}
> +
> +	err = send_message(input);
> +
> +	if (err < 0)
> +		return err;
> +
> +	evn.events = EPOLLIN;
> +	evn.data.fd = nl_sock;
> +	if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, nl_sock, &evn) < 0) {
> +		ret_errno = errno;
> +		perror("epoll_ctl failed");
> +		return -3;
> +	}
> +	*efd = epoll_fd;
> +	return 0;
> +}
> +
> +static void sigint(int sig)
> +{
> +	interrupted = 1;
> +}
> +
> +int handle_packet(char *buff, int fd, struct proc_event *event)
> +{
> +	struct nlmsghdr *hdr;
> +
> +	hdr = (struct nlmsghdr *)buff;
> +
> +	if (hdr->nlmsg_type == NLMSG_ERROR) {
> +		perror("NLMSG_ERROR error\n");
> +		return -3;
> +	} else if (hdr->nlmsg_type == NLMSG_DONE) {
> +		event = (struct proc_event *)
> +			((struct cn_msg *)NLMSG_DATA(hdr))->data;
> +		tcount++;
> +		switch (event->what) {
> +		case PROC_EVENT_EXIT:
> +			Printf("Exit process %d (tgid %d) with code %d, signal %d\n",
> +			       event->event_data.exit.process_pid,
> +			       event->event_data.exit.process_tgid,
> +			       event->event_data.exit.exit_code,
> +			       event->event_data.exit.exit_signal);
> +			break;
> +		case PROC_EVENT_FORK:
> +			Printf("Fork process %d (tgid %d), parent %d (tgid %d)\n",
> +			       event->event_data.fork.child_pid,
> +			       event->event_data.fork.child_tgid,
> +			       event->event_data.fork.parent_pid,
> +			       event->event_data.fork.parent_tgid);
> +			break;
> +		case PROC_EVENT_EXEC:
> +			Printf("Exec process %d (tgid %d)\n",
> +			       event->event_data.exec.process_pid,
> +			       event->event_data.exec.process_tgid);
> +			break;
> +		case PROC_EVENT_UID:
> +			Printf("UID process %d (tgid %d) uid %d euid %d\n",
> +			       event->event_data.id.process_pid,
> +			       event->event_data.id.process_tgid,
> +			       event->event_data.id.r.ruid,
> +			       event->event_data.id.e.euid);
> +			break;
> +		case PROC_EVENT_GID:
> +			Printf("GID process %d (tgid %d) gid %d egid %d\n",
> +			       event->event_data.id.process_pid,
> +			       event->event_data.id.process_tgid,
> +			       event->event_data.id.r.rgid,
> +			       event->event_data.id.e.egid);
> +			break;
> +		case PROC_EVENT_SID:
> +			Printf("SID process %d (tgid %d)\n",
> +			       event->event_data.sid.process_pid,
> +			       event->event_data.sid.process_tgid);
> +			break;
> +		case PROC_EVENT_PTRACE:
> +			Printf("Ptrace process %d (tgid %d), Tracer %d (tgid %d)\n",
> +			       event->event_data.ptrace.process_pid,
> +			       event->event_data.ptrace.process_tgid,
> +			       event->event_data.ptrace.tracer_pid,
> +			       event->event_data.ptrace.tracer_tgid);
> +			break;
> +		case PROC_EVENT_COMM:
> +			Printf("Comm process %d (tgid %d) comm %s\n",
> +			       event->event_data.comm.process_pid,
> +			       event->event_data.comm.process_tgid,
> +			       event->event_data.comm.comm);
> +			break;
> +		case PROC_EVENT_COREDUMP:
> +			Printf("Coredump process %d (tgid %d) parent %d, (tgid %d)\n",
> +			       event->event_data.coredump.process_pid,
> +			       event->event_data.coredump.process_tgid,
> +			       event->event_data.coredump.parent_pid,
> +			       event->event_data.coredump.parent_tgid);
> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +	return 0;
> +}
> +
> +int handle_events(int epoll_fd, struct proc_event *pev)
> +{
> +	char buff[CONNECTOR_MAX_MSG_SIZE];
> +	struct epoll_event ev[MAX_EVENTS];
> +	int i, event_count = 0, err = 0;
> +
> +	event_count = epoll_wait(epoll_fd, ev, MAX_EVENTS, -1);
> +	if (event_count < 0) {
> +		ret_errno = errno;
> +		if (ret_errno != EINTR)
> +			perror("epoll_wait failed");
> +		return -3;
> +	}
> +	for (i = 0; i < event_count; i++) {
> +		if (!(ev[i].events & EPOLLIN))
> +			continue;
> +		if (recv(ev[i].data.fd, buff, sizeof(buff), 0) == -1) {
> +			ret_errno = errno;
> +			perror("recv failed");
> +			return -3;
> +		}
> +		err = handle_packet(buff, ev[i].data.fd, pev);
> +		if (err < 0)
> +			return err;
> +	}
> +	return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	int epoll_fd, err;
> +	struct proc_event proc_ev;
> +	struct proc_input input;
> +
> +	signal(SIGINT, sigint);
> +
> +	if (argc > 2) {
> +		printf("Expected 0(assume no-filter) or 1 argument(-f)\n");
> +		exit(1);
> +	}
> +
> +	if (argc == 2) {
> +		if (strcmp(argv[1], "-f") == 0) {
> +			filter = 1;
> +		} else {
> +			printf("Valid option : -f (for filter feature)\n");
> +			exit(1);
> +		}
> +	}
> +
> +	if (filter) {
> +		input.event_type = PROC_EVENT_NONZERO_EXIT;
> +		input.mcast_op = PROC_CN_MCAST_LISTEN;
> +		err = register_proc_netlink(&epoll_fd, (void*)&input);
> +	} else {
> +		enum proc_cn_mcast_op op = PROC_CN_MCAST_LISTEN;
> +		err = register_proc_netlink(&epoll_fd, (void*)&op);
> +	}
> +
> +	if (err < 0) {
 
 -2 is ENOENT, -3 is ESRCH (no such process), so I think you won't have
 collisions with the send_message() returns.  Ah, but this is test code
 so it's probably fine.

> +		if (err == -2)
> +			close(nl_sock);
> +		if (err == -3) {
> +			close(nl_sock);
> +			close(epoll_fd);
> +		}
> +		exit(1);
> +	}
> +
> +	while (!interrupted) {
> +		err = handle_events(epoll_fd, &proc_ev);
> +		if (err < 0) {
> +			if (ret_errno == EINTR)
> +				continue;
> +			if (err == -2)
> +				close(nl_sock);
> +			if (err == -3) {
> +				close(nl_sock);
> +				close(epoll_fd);
> +			}
> +			exit(1);
> +		}
> +	}
> +
> +	if (filter) {
> +		input.mcast_op = PROC_CN_MCAST_IGNORE;
> +		send_message((void*)&input);
> +	} else {
> +		enum proc_cn_mcast_op op = PROC_CN_MCAST_IGNORE;
> +		send_message((void*)&op);
> +	}
> +
> +	close(epoll_fd);
> +	close(nl_sock);
> +
> +	printf("Done total count: %d\n", tcount);
> +	exit(0);
> +}
> -- 
> 2.41.0
>