Re: [PATCH v6 6/6] connector/cn_proc: Selftest for proc connector

From: Anjali Kulkarni
Date: Mon Jul 03 2023 - 15:18:27 EST

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> On Jun 30, 2023, at 6:43 PM, Liam Howlett <liam.howlett@xxxxxxxxxx> wrote:
>
> * Anjali Kulkarni <anjali.k.kulkarni@xxxxxxxxxx> [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@xxxxxxxxxx>
>> ---
>> 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.

Will fix it.

>
>> + } 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.

Yes, these are just internal error codes to this program..

>
>> + 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

Next message: Tejun Heo: "Re: [PATCH] cgroup/cpuset: update parent subparts cpumask while holding css refcnt"
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