// 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 <time.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 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]\n");
        fprintf(stderr, "  -d: print delayacct stats\n");
        fprintf(stderr, "  -i: print IO accounting (works only with -p)\n");
        fprintf(stderr, "  -l: listen forever\n");
        fprintf(stderr, "  -v: debug on\n");
        fprintf(stderr, "  -C: container path\n");
}

/*
 * 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\n",
                                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 + 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))
#define delay_ms(t) (t / 1000000ULL)

/*
 * Format __kernel_timespec to human readable string (YYYY-MM-DD HH:MM:SS)
 * Returns formatted string or "N/A" if timestamp is zero
 */
static const char *format_timespec(struct __kernel_timespec *ts)
{
        static char buffer[32];
        struct tm tm_info;
        __kernel_time_t time_sec;

        /* Check if timestamp is zero (not set) */
        if (ts->tv_sec == 0 && ts->tv_nsec == 0)
                return "N/A";

        time_sec = ts->tv_sec;

        /* Use thread-safe localtime_r */
        if (localtime_r(&time_sec, &tm_info) == NULL)
                return "N/A";

        snprintf(buffer, sizeof(buffer), "%04d-%02d-%02dT%02d:%02d:%02d",
                tm_info.tm_year + 1900,
                tm_info.tm_mon + 1,
                tm_info.tm_mday,
                tm_info.tm_hour,
                tm_info.tm_min,
                tm_info.tm_sec);

        return buffer;
}

/*
 * Version compatibility note:
 * Field availability depends on taskstats version (t->version),
 * corresponding to TASKSTATS_VERSION in kernel headers
 * see include/uapi/linux/taskstats.h
 *
 * Version feature mapping:
 * version >= 11  - supports COMPACT statistics
 * version >= 13  - supports WPCOPY statistics
 * version >= 14  - supports IRQ statistics
 * version >= 16  - supports *_max and *_min delay statistics
 * version >= 17  - supports delay max timestamp statistics
 *
 * Always verify version before accessing version-dependent fields
 * to maintain backward compatibility.
 */
#define PRINT_CPU_DELAY(version, t) \
        do { \
                if (version >= 17) { \
                        printf("%-10s%15s%15s%15s%15s%15s%15s%15s%25s\n", \
                                "CPU", "count", "real total", "virtual total", \
                                "delay total", "delay average", "delay max", \
                                "delay min", "delay max timestamp"); \
                        printf("          %15llu%15llu%15llu%15llu%15.3fms%13.6fms%13.6fms%23s\n", \
                                (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), \
                                delay_ms((double)(t)->cpu_delay_max), \
                                delay_ms((double)(t)->cpu_delay_min), \
                                format_timespec(&(t)->cpu_delay_max_ts)); \
                } else if (version >= 16) { \
                        printf("%-10s%15s%15s%15s%15s%15s%15s%15s\n", \
                                "CPU", "count", "real total", "virtual total", \
                                "delay total", "delay average", "delay max", "delay min"); \
                        printf("          %15llu%15llu%15llu%15llu%15.3fms%13.6fms%13.6fms\n", \
                                (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), \
                                delay_ms((double)(t)->cpu_delay_max), \
                                delay_ms((double)(t)->cpu_delay_min)); \
                } else { \
                        printf("%-10s%15s%15s%15s%15s%15s\n", \
                                "CPU", "count", "real total", "virtual total", \
                                "delay total", "delay average"); \
                        printf("          %15llu%15llu%15llu%15llu%15.3fms\n", \
                                (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)); \
                } \
        } while (0)
#define PRINT_FILED_DELAY(name, version, t, count, total, max, min) \
        do { \
                if (version >= 16) { \
                        printf("%-10s%15s%15s%15s%15s%15s\n", \
                                name, "count", "delay total", "delay average", \
                                "delay max", "delay min"); \
                        printf("          %15llu%15llu%15.3fms%13.6fms%13.6fms\n", \
                                (unsigned long long)(t)->count, \
                                (unsigned long long)(t)->total, \
                                average_ms((double)(t)->total, (t)->count), \
                                delay_ms((double)(t)->max), \
                                delay_ms((double)(t)->min)); \
                } else { \
                        printf("%-10s%15s%15s%15s\n", \
                                name, "count", "delay total", "delay average"); \
                        printf("          %15llu%15llu%15.3fms\n", \
                                (unsigned long long)(t)->count, \
                                (unsigned long long)(t)->total, \
                                average_ms((double)(t)->total, (t)->count)); \
                } \
        } while (0)

#define PRINT_FILED_DELAY_WITH_TS(name, version, t, count, total, max, min, max_ts) \
        do { \
                if (version >= 17) { \
                        printf("%-10s%15s%15s%15s%15s%15s%25s\n", \
                                name, "count", "delay total", "delay average", \
                                "delay max", "delay min", "delay max timestamp"); \
                        printf("          %15llu%15llu%15.3fms%13.6fms%13.6fms%23s\n", \
                                (unsigned long long)(t)->count, \
                                (unsigned long long)(t)->total, \
                                average_ms((double)(t)->total, (t)->count), \
                                delay_ms((double)(t)->max), \
                                delay_ms((double)(t)->min), \
                                format_timespec(&(t)->max_ts)); \
                } else if (version >= 16) { \
                        printf("%-10s%15s%15s%15s%15s%15s\n", \
                                name, "count", "delay total", "delay average", \
                                "delay max", "delay min"); \
                        printf("          %15llu%15llu%15.3fms%13.6fms%13.6fms\n", \
                                (unsigned long long)(t)->count, \
                                (unsigned long long)(t)->total, \
                                average_ms((double)(t)->total, (t)->count), \
                                delay_ms((double)(t)->max), \
                                delay_ms((double)(t)->min)); \
                } else { \
                        printf("%-10s%15s%15s%15s\n", \
                                name, "count", "delay total", "delay average"); \
                        printf("          %15llu%15llu%15.3fms\n", \
                                (unsigned long long)(t)->count, \
                                (unsigned long long)(t)->total, \
                                average_ms((double)(t)->total, (t)->count)); \
                } \
        } while (0)

static void print_delayacct(struct taskstats *t)
{
        printf("\n\n");

        PRINT_CPU_DELAY(t->version, t);

        /* Use new macro with timestamp support for version >= 17 */
        if (t->version >= 17) {
                PRINT_FILED_DELAY_WITH_TS("IO", t->version, t,
                        blkio_count, blkio_delay_total,
                        blkio_delay_max, blkio_delay_min, blkio_delay_max_ts);

                PRINT_FILED_DELAY_WITH_TS("SWAP", t->version, t,
                        swapin_count, swapin_delay_total,
                        swapin_delay_max, swapin_delay_min, swapin_delay_max_ts);

                PRINT_FILED_DELAY_WITH_TS("RECLAIM", t->version, t,
                        freepages_count, freepages_delay_total,
                        freepages_delay_max, freepages_delay_min, freepages_delay_max_ts);

                PRINT_FILED_DELAY_WITH_TS("THRASHING", t->version, t,
                        thrashing_count, thrashing_delay_total,
                        thrashing_delay_max, thrashing_delay_min, thrashing_delay_max_ts);

                if (t->version >= 11) {
                        PRINT_FILED_DELAY_WITH_TS("COMPACT", t->version, t,
                                compact_count, compact_delay_total,
                                compact_delay_max, compact_delay_min, compact_delay_max_ts);
                }

                if (t->version >= 13) {
                        PRINT_FILED_DELAY_WITH_TS("WPCOPY", t->version, t,
                                wpcopy_count, wpcopy_delay_total,
                                wpcopy_delay_max, wpcopy_delay_min, wpcopy_delay_max_ts);
                }

                if (t->version >= 14) {
                        PRINT_FILED_DELAY_WITH_TS("IRQ", t->version, t,
                                irq_count, irq_delay_total,
                                irq_delay_max, irq_delay_min, irq_delay_max_ts);
                }
        } else {
                /* Use original macro for older versions */
                PRINT_FILED_DELAY("IO", t->version, t,
                        blkio_count, blkio_delay_total,
                        blkio_delay_max, blkio_delay_min);

                PRINT_FILED_DELAY("SWAP", t->version, t,
                        swapin_count, swapin_delay_total,
                        swapin_delay_max, swapin_delay_min);

                PRINT_FILED_DELAY("RECLAIM", t->version, t,
                        freepages_count, freepages_delay_total,
                        freepages_delay_max, freepages_delay_min);

                PRINT_FILED_DELAY("THRASHING", t->version, t,
                        thrashing_count, thrashing_delay_total,
                        thrashing_delay_max, thrashing_delay_min);

                if (t->version >= 11) {
                        PRINT_FILED_DELAY("COMPACT", t->version, t,
                                compact_count, compact_delay_total,
                                compact_delay_max, compact_delay_min);
                }

                if (t->version >= 13) {
                        PRINT_FILED_DELAY("WPCOPY", t->version, t,
                                wpcopy_count, wpcopy_delay_total,
                                wpcopy_delay_max, wpcopy_delay_min);
                }

                if (t->version >= 14) {
                        PRINT_FILED_DELAY("IRQ", t->version, t,
                                irq_count, irq_delay_total,
                                irq_delay_max, irq_delay_min);
                }
        }
}

static void task_context_switch_counts(struct taskstats *t)
{
        printf("\n\nTask   %15s%15s\n"
               "       %15llu%15llu\n",
               "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\n", (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\n",
                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 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\n");
                        print_delays = 1;
                        break;
                case 'i':
                        printf("printing IO accounting\n");
                        print_io_accounting = 1;
                        break;
                case 'q':
                        printf("printing task/process context switch rates\n");
                        print_task_context_switch_counts = 1;
                        break;
                case 'C':
                        containerset = 1;
                        containerpath = optarg;
                        break;
                case 'w':
                        logfile = strdup(optarg);
                        printf("write to file %s\n", logfile);
                        write_file = 1;
                        break;
                case 'r':
                        rcvbufsz = atoi(optarg);
                        printf("receive buf size %d\n", rcvbufsz);
                        if (rcvbufsz < 0)
                                err(1, "Invalid rcv buf size\n");
                        break;
                case 'm':
                        strncpy(cpumask, optarg, sizeof(cpumask));
                        cpumask[sizeof(cpumask) - 1] = '\0';
                        maskset = 1;
                        printf("cpumask %s maskset %d\n", cpumask, maskset);
                        break;
                case 't':
                        tid = atoi(optarg);
                        if (!tid)
                                err(1, "Invalid tgid\n");
                        cmd_type = TASKSTATS_CMD_ATTR_TGID;
                        break;
                case 'p':
                        tid = atoi(optarg);
                        if (!tid)
                                err(1, "Invalid pid\n");
                        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\n");
                        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\n");
                        dbg = 1;
                        break;
                case 'l':
                        printf("listen forever\n");
                        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\n");
                        exit(1);
                }
        }

        nl_sd = create_nl_socket(NETLINK_GENERIC);
        if (nl_sd < 0)
                err(1, "error creating Netlink socket\n");


        mypid = getpid();
        id = get_family_id(nl_sd);
        if (!id) {
                fprintf(stderr, "Error getting family id, errno %d\n", errno);
                goto err;
        }
        PRINTF("family id %d\n", 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\n", rc);
                if (rc < 0) {
                        fprintf(stderr, "error sending register cpumask\n");
                        goto err;
                }
        }

        if (tid && containerset) {
                fprintf(stderr, "Select either -t or -C, not both\n");
                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\n", rc);
                if (rc < 0) {
                        fprintf(stderr, "error sending tid/tgid cmd\n");
                        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\n", rep_len);

                if (rep_len < 0) {
                        fprintf(stderr, "nonfatal reply error: errno %d\n",
                                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\n",
                                err->error);
                        goto done;
                }

                PRINTF("nlmsghdr size=%zu, nlmsg_len=%d, rep_len=%d\n",
                       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);
                                while (len2 < aggr_len) {
                                        switch (na->nla_type) {
                                        case TASKSTATS_TYPE_PID:
                                                rtid = *(int *) NLA_DATA(na);
                                                if (print_delays)
                                                        printf("PID\t%d\n", rtid);
                                                break;
                                        case TASKSTATS_TYPE_TGID:
                                                rtid = *(int *) NLA_DATA(na);
                                                if (print_delays)
                                                        printf("TGID\t%d\n", rtid);
                                                break;
                                        case TASKSTATS_TYPE_STATS:
                                                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\n");
                                                        }
                                                }
                                                if (!loop)
                                                        goto done;
                                                break;
                                        case TASKSTATS_TYPE_NULL:
                                                break;
                                        default:
                                                fprintf(stderr, "Unknown nested"
                                                        " nla_type %d\n",
                                                        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\n",
                                        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\n", rc);
                if (rc < 0)
                        err(rc, "error sending deregister cpumask\n");
        }
err:
        close(nl_sd);
        if (fd)
                close(fd);
        if (cfd)
                close(cfd);
        return 0;
}