// SPDX-License-Identifier: GPL-2.0

  /* getdelays.c
   *
   * Utility to get per-pid and per-tgid delay accounting statistics
   * Also illustrates usage of the taskstats interface
   *
   * Copyright (C) Shailabh Nagar, IBM Corp. 2005
   * Copyright (C) Balbir Singh, IBM Corp. 2006

   * Copyright (c) Jay Lan, SGI. 2006

   *

   * Compile with
   *	gcc -I/usr/src/linux/include getdelays.c -o getdelays

   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <errno.h>
  #include <unistd.h>
  #include <poll.h>
  #include <string.h>
  #include <fcntl.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/socket.h>

  #include <sys/wait.h>

  #include <signal.h>
  
  #include <linux/genetlink.h>
  #include <linux/taskstats.h>

  #include <linux/cgroupstats.h>

  
  /*
   * Generic macros for dealing with netlink sockets. Might be duplicated
   * elsewhere. It is recommended that commercial grade applications use
   * libnl or libnetlink and use the interfaces provided by the library
   */
  #define GENLMSG_DATA(glh)	((void *)(NLMSG_DATA(glh) + GENL_HDRLEN))
  #define GENLMSG_PAYLOAD(glh)	(NLMSG_PAYLOAD(glh, 0) - GENL_HDRLEN)
  #define NLA_DATA(na)		((void *)((char*)(na) + NLA_HDRLEN))
  #define NLA_PAYLOAD(len)	(len - NLA_HDRLEN)

  #define err(code, fmt, arg...)			\
  	do {					\
  		fprintf(stderr, fmt, ##arg);	\
  		exit(code);			\
  	} while (0)
  
  int done;
  int rcvbufsz;
  char name[100];
  int dbg;
  int print_delays;

  int print_io_accounting;

  int print_task_context_switch_counts;

  #define PRINTF(fmt, arg...) {			\
  	    if (dbg) {				\
  		printf(fmt, ##arg);		\
  	    }					\
  	}
  
  /* Maximum size of response requested or message sent */

  #define MAX_MSG_SIZE	1024

  /* Maximum number of cpus expected to be specified in a cpumask */
  #define MAX_CPUS	32

  
  struct msgtemplate {
  	struct nlmsghdr n;
  	struct genlmsghdr g;
  	char buf[MAX_MSG_SIZE];
  };
  
  char cpumask[100+6*MAX_CPUS];

  static void usage(void)
  {
  	fprintf(stderr, "getdelays [-dilv] [-w logfile] [-r bufsize] "
  			"[-m cpumask] [-t tgid] [-p pid]
  ");
  	fprintf(stderr, "  -d: print delayacct stats
  ");
  	fprintf(stderr, "  -i: print IO accounting (works only with -p)
  ");
  	fprintf(stderr, "  -l: listen forever
  ");
  	fprintf(stderr, "  -v: debug on
  ");

  	fprintf(stderr, "  -C: container path
  ");

  }

  /*
   * Create a raw netlink socket and bind
   */

  static int create_nl_socket(int protocol)

  {

  	int fd;
  	struct sockaddr_nl local;
  
  	fd = socket(AF_NETLINK, SOCK_RAW, protocol);
  	if (fd < 0)
  		return -1;
  
  	if (rcvbufsz)
  		if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF,
  				&rcvbufsz, sizeof(rcvbufsz)) < 0) {

  			fprintf(stderr, "Unable to set socket rcv buf size to %d
  ",

  				rcvbufsz);

  			goto error;

  		}

  	memset(&local, 0, sizeof(local));
  	local.nl_family = AF_NETLINK;

  	if (bind(fd, (struct sockaddr *) &local, sizeof(local)) < 0)
  		goto error;

  	return fd;
  error:
  	close(fd);
  	return -1;

  }

  static int send_cmd(int sd, __u16 nlmsg_type, __u32 nlmsg_pid,

  	     __u8 genl_cmd, __u16 nla_type,
  	     void *nla_data, int nla_len)

  {

  	struct nlattr *na;
  	struct sockaddr_nl nladdr;
  	int r, buflen;
  	char *buf;
  
  	struct msgtemplate msg;
  
  	msg.n.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
  	msg.n.nlmsg_type = nlmsg_type;
  	msg.n.nlmsg_flags = NLM_F_REQUEST;
  	msg.n.nlmsg_seq = 0;
  	msg.n.nlmsg_pid = nlmsg_pid;
  	msg.g.cmd = genl_cmd;
  	msg.g.version = 0x1;
  	na = (struct nlattr *) GENLMSG_DATA(&msg);
  	na->nla_type = nla_type;
  	na->nla_len = nla_len + 1 + NLA_HDRLEN;
  	memcpy(NLA_DATA(na), nla_data, nla_len);
  	msg.n.nlmsg_len += NLMSG_ALIGN(na->nla_len);
  
  	buf = (char *) &msg;
  	buflen = msg.n.nlmsg_len ;
  	memset(&nladdr, 0, sizeof(nladdr));
  	nladdr.nl_family = AF_NETLINK;
  	while ((r = sendto(sd, buf, buflen, 0, (struct sockaddr *) &nladdr,
  			   sizeof(nladdr))) < buflen) {
  		if (r > 0) {
  			buf += r;
  			buflen -= r;
  		} else if (errno != EAGAIN)
  			return -1;
  	}
  	return 0;

  }

  /*
   * Probe the controller in genetlink to find the family id
   * for the TASKSTATS family
   */

  static int get_family_id(int sd)

  {

  	struct {
  		struct nlmsghdr n;
  		struct genlmsghdr g;
  		char buf[256];
  	} ans;

  	int id = 0, rc;

  	struct nlattr *na;
  	int rep_len;
  
  	strcpy(name, TASKSTATS_GENL_NAME);
  	rc = send_cmd(sd, GENL_ID_CTRL, getpid(), CTRL_CMD_GETFAMILY,
  			CTRL_ATTR_FAMILY_NAME, (void *)name,
  			strlen(TASKSTATS_GENL_NAME)+1);

  	if (rc < 0)
  		return 0;	/* sendto() failure? */

  
  	rep_len = recv(sd, &ans, sizeof(ans), 0);
  	if (ans.n.nlmsg_type == NLMSG_ERROR ||
  	    (rep_len < 0) || !NLMSG_OK((&ans.n), rep_len))
  		return 0;

  	na = (struct nlattr *) GENLMSG_DATA(&ans);
  	na = (struct nlattr *) ((char *) na + NLA_ALIGN(na->nla_len));
  	if (na->nla_type == CTRL_ATTR_FAMILY_ID) {
  		id = *(__u16 *) NLA_DATA(na);
  	}
  	return id;

  }

  #define average_ms(t, c) (t / 1000000ULL / (c ? c : 1))

  static void print_delayacct(struct taskstats *t)

  {

  	printf("
  
  CPU   %15s%15s%15s%15s%15s
  "
  	       "      %15llu%15llu%15llu%15llu%15.3fms
  "
  	       "IO    %15s%15s%15s
  "
  	       "      %15llu%15llu%15llums
  "
  	       "SWAP  %15s%15s%15s
  "
  	       "      %15llu%15llu%15llums
  "
  	       "RECLAIM  %12s%15s%15s
  "
  	       "      %15llu%15llu%15llums
  ",
  	       "count", "real total", "virtual total",
  	       "delay total", "delay average",

  	       (unsigned long long)t->cpu_count,
  	       (unsigned long long)t->cpu_run_real_total,
  	       (unsigned long long)t->cpu_run_virtual_total,
  	       (unsigned long long)t->cpu_delay_total,

  	       average_ms((double)t->cpu_delay_total, t->cpu_count),
  	       "count", "delay total", "delay average",

  	       (unsigned long long)t->blkio_count,
  	       (unsigned long long)t->blkio_delay_total,

  	       average_ms(t->blkio_delay_total, t->blkio_count),
  	       "count", "delay total", "delay average",

  	       (unsigned long long)t->swapin_count,
  	       (unsigned long long)t->swapin_delay_total,

  	       average_ms(t->swapin_delay_total, t->swapin_count),
  	       "count", "delay total", "delay average",

  	       (unsigned long long)t->freepages_count,

  	       (unsigned long long)t->freepages_delay_total,
  	       average_ms(t->freepages_delay_total, t->freepages_count));

  }

  static void task_context_switch_counts(struct taskstats *t)

  {
  	printf("
  
  Task   %15s%15s
  "

  	       "       %15llu%15llu
  ",

  	       "voluntary", "nonvoluntary",

  	       (unsigned long long)t->nvcsw, (unsigned long long)t->nivcsw);

  }

  static void print_cgroupstats(struct cgroupstats *c)

  {
  	printf("sleeping %llu, blocked %llu, running %llu, stopped %llu, "

  		"uninterruptible %llu
  ", (unsigned long long)c->nr_sleeping,
  		(unsigned long long)c->nr_io_wait,
  		(unsigned long long)c->nr_running,
  		(unsigned long long)c->nr_stopped,
  		(unsigned long long)c->nr_uninterruptible);

  }

  static void print_ioacct(struct taskstats *t)

  {
  	printf("%s: read=%llu, write=%llu, cancelled_write=%llu
  ",
  		t->ac_comm,
  		(unsigned long long)t->read_bytes,
  		(unsigned long long)t->write_bytes,
  		(unsigned long long)t->cancelled_write_bytes);
  }

  int main(int argc, char *argv[])
  {

  	int c, rc, rep_len, aggr_len, len2;
  	int cmd_type = TASKSTATS_CMD_ATTR_UNSPEC;

  	__u16 id;
  	__u32 mypid;
  
  	struct nlattr *na;
  	int nl_sd = -1;
  	int len = 0;
  	pid_t tid = 0;
  	pid_t rtid = 0;
  
  	int fd = 0;
  	int count = 0;
  	int write_file = 0;
  	int maskset = 0;

  	char *logfile = NULL;

  	int loop = 0;

  	int containerset = 0;

  	char *containerpath = NULL;

  	int cfd = 0;

  	int forking = 0;
  	sigset_t sigset;

  
  	struct msgtemplate msg;

  	while (!forking) {
  		c = getopt(argc, argv, "qdiw:r:m:t:p:vlC:c:");

  		if (c < 0)
  			break;

  		switch (c) {
  		case 'd':
  			printf("print delayacct stats ON
  ");
  			print_delays = 1;
  			break;

  		case 'i':
  			printf("printing IO accounting
  ");
  			print_io_accounting = 1;
  			break;

  		case 'q':
  			printf("printing task/process context switch rates
  ");
  			print_task_context_switch_counts = 1;
  			break;

  		case 'C':
  			containerset = 1;

  			containerpath = optarg;

  			break;

  		case 'w':

  			logfile = strdup(optarg);

  			printf("write to file %s
  ", logfile);
  			write_file = 1;
  			break;
  		case 'r':
  			rcvbufsz = atoi(optarg);
  			printf("receive buf size %d
  ", rcvbufsz);
  			if (rcvbufsz < 0)
  				err(1, "Invalid rcv buf size
  ");
  			break;
  		case 'm':
  			strncpy(cpumask, optarg, sizeof(cpumask));

  			cpumask[sizeof(cpumask) - 1] = '\0';

  			maskset = 1;
  			printf("cpumask %s maskset %d
  ", cpumask, maskset);
  			break;
  		case 't':
  			tid = atoi(optarg);
  			if (!tid)
  				err(1, "Invalid tgid
  ");
  			cmd_type = TASKSTATS_CMD_ATTR_TGID;

  			break;
  		case 'p':
  			tid = atoi(optarg);
  			if (!tid)
  				err(1, "Invalid pid
  ");
  			cmd_type = TASKSTATS_CMD_ATTR_PID;

  			break;

  		case 'c':
  
  			/* Block SIGCHLD for sigwait() later */
  			if (sigemptyset(&sigset) == -1)
  				err(1, "Failed to empty sigset");
  			if (sigaddset(&sigset, SIGCHLD))
  				err(1, "Failed to set sigchld in sigset");
  			sigprocmask(SIG_BLOCK, &sigset, NULL);
  
  			/* fork/exec a child */
  			tid = fork();
  			if (tid < 0)
  				err(1, "Fork failed
  ");
  			if (tid == 0)
  				if (execvp(argv[optind - 1],
  				    &argv[optind - 1]) < 0)
  					exit(-1);
  
  			/* Set the command type and avoid further processing */
  			cmd_type = TASKSTATS_CMD_ATTR_PID;
  			forking = 1;
  			break;

  		case 'v':
  			printf("debug on
  ");
  			dbg = 1;
  			break;
  		case 'l':
  			printf("listen forever
  ");
  			loop = 1;
  			break;
  		default:

  			usage();

  			exit(-1);

  		}

  	}

  	if (write_file) {
  		fd = open(logfile, O_WRONLY | O_CREAT | O_TRUNC,
  			  S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
  		if (fd == -1) {
  			perror("Cannot open output file
  ");
  			exit(1);
  		}
  	}

  	nl_sd = create_nl_socket(NETLINK_GENERIC);
  	if (nl_sd < 0)

  		err(1, "error creating Netlink socket
  ");

  	mypid = getpid();
  	id = get_family_id(nl_sd);
  	if (!id) {

  		fprintf(stderr, "Error getting family id, errno %d
  ", errno);

  		goto err;

  	}

  	PRINTF("family id %d
  ", id);
  
  	if (maskset) {
  		rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
  			      TASKSTATS_CMD_ATTR_REGISTER_CPUMASK,

  			      &cpumask, strlen(cpumask) + 1);

  		PRINTF("Sent register cpumask, retval %d
  ", rc);
  		if (rc < 0) {

  			fprintf(stderr, "error sending register cpumask
  ");

  			goto err;
  		}

  	}

  	if (tid && containerset) {
  		fprintf(stderr, "Select either -t or -C, not both
  ");
  		goto err;
  	}

  	/*
  	 * If we forked a child, wait for it to exit. Cannot use waitpid()
  	 * as all the delicious data would be reaped as part of the wait
  	 */
  	if (tid && forking) {
  		int sig_received;
  		sigwait(&sigset, &sig_received);
  	}

  	if (tid) {
  		rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
  			      cmd_type, &tid, sizeof(__u32));
  		PRINTF("Sent pid/tgid, retval %d
  ", rc);
  		if (rc < 0) {

  			fprintf(stderr, "error sending tid/tgid cmd
  ");

  			goto done;
  		}

  	}

  	if (containerset) {
  		cfd = open(containerpath, O_RDONLY);
  		if (cfd < 0) {
  			perror("error opening container file");
  			goto err;
  		}
  		rc = send_cmd(nl_sd, id, mypid, CGROUPSTATS_CMD_GET,
  			      CGROUPSTATS_CMD_ATTR_FD, &cfd, sizeof(__u32));
  		if (rc < 0) {
  			perror("error sending cgroupstats command");
  			goto err;
  		}
  	}

  	if (!maskset && !tid && !containerset) {
  		usage();
  		goto err;
  	}

  	do {

  		rep_len = recv(nl_sd, &msg, sizeof(msg), 0);
  		PRINTF("received %d bytes
  ", rep_len);

  		if (rep_len < 0) {

  			fprintf(stderr, "nonfatal reply error: errno %d
  ",
  				errno);

  			continue;
  		}
  		if (msg.n.nlmsg_type == NLMSG_ERROR ||
  		    !NLMSG_OK((&msg.n), rep_len)) {

  			struct nlmsgerr *err = NLMSG_DATA(&msg);

  			fprintf(stderr, "fatal reply error,  errno %d
  ",
  				err->error);

  			goto done;
  		}

  		PRINTF("nlmsghdr size=%zu, nlmsg_len=%d, rep_len=%d
  ",

  		       sizeof(struct nlmsghdr), msg.n.nlmsg_len, rep_len);
  
  
  		rep_len = GENLMSG_PAYLOAD(&msg.n);
  
  		na = (struct nlattr *) GENLMSG_DATA(&msg);
  		len = 0;

  		while (len < rep_len) {
  			len += NLA_ALIGN(na->nla_len);
  			switch (na->nla_type) {
  			case TASKSTATS_TYPE_AGGR_TGID:
  				/* Fall through */
  			case TASKSTATS_TYPE_AGGR_PID:
  				aggr_len = NLA_PAYLOAD(na->nla_len);
  				len2 = 0;
  				/* For nested attributes, na follows */
  				na = (struct nlattr *) NLA_DATA(na);
  				done = 0;
  				while (len2 < aggr_len) {
  					switch (na->nla_type) {
  					case TASKSTATS_TYPE_PID:
  						rtid = *(int *) NLA_DATA(na);
  						if (print_delays)
  							printf("PID\t%d
  ", rtid);
  						break;
  					case TASKSTATS_TYPE_TGID:
  						rtid = *(int *) NLA_DATA(na);
  						if (print_delays)
  							printf("TGID\t%d
  ", rtid);
  						break;
  					case TASKSTATS_TYPE_STATS:
  						count++;
  						if (print_delays)
  							print_delayacct((struct taskstats *) NLA_DATA(na));

  						if (print_io_accounting)
  							print_ioacct((struct taskstats *) NLA_DATA(na));

  						if (print_task_context_switch_counts)
  							task_context_switch_counts((struct taskstats *) NLA_DATA(na));

  						if (fd) {
  							if (write(fd, NLA_DATA(na), na->nla_len) < 0) {
  								err(1,"write error
  ");
  							}
  						}
  						if (!loop)
  							goto done;
  						break;

  					case TASKSTATS_TYPE_NULL:
  						break;

  					default:

  						fprintf(stderr, "Unknown nested"
  							" nla_type %d
  ",
  							na->nla_type);

  						break;
  					}
  					len2 += NLA_ALIGN(na->nla_len);

  					na = (struct nlattr *)((char *)na +
  							       NLA_ALIGN(na->nla_len));

  				}
  				break;

  			case CGROUPSTATS_TYPE_CGROUP_STATS:
  				print_cgroupstats(NLA_DATA(na));
  				break;

  			default:

  				fprintf(stderr, "Unknown nla_type %d
  ",
  					na->nla_type);

  			case TASKSTATS_TYPE_NULL:

  				break;

  			}

  			na = (struct nlattr *) (GENLMSG_DATA(&msg) + len);

  		}

  	} while (loop);
  done:
  	if (maskset) {
  		rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
  			      TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK,

  			      &cpumask, strlen(cpumask) + 1);

  		printf("Sent deregister mask, retval %d
  ", rc);
  		if (rc < 0)
  			err(rc, "error sending deregister cpumask
  ");

  	}

  err:
  	close(nl_sd);
  	if (fd)
  		close(fd);

  	if (cfd)
  		close(cfd);

  	return 0;

  }