/*****************************************************************************\
 *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
 *  Copyright (C) 2007 The Regents of the University of California.
 *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
 *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
 *  UCRL-CODE-235197
 *
 *  This file is part of the SPL, Solaris Porting Layer.
 *  For details, see <http://github.com/behlendorf/spl/>.
 *
 *  The SPL 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.
 *
 *  The SPL 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 the SPL.  If not, see <http://www.gnu.org/licenses/>.
 *****************************************************************************
 *  Solaris Porting Layer (SPL) Kstat Implementation.
\*****************************************************************************/

#include <linux/seq_file.h>
#include <sys/kstat.h>
#include <spl-debug.h>

#ifdef SS_DEBUG_SUBSYS
#undef SS_DEBUG_SUBSYS
#endif

#define SS_DEBUG_SUBSYS SS_KSTAT

static spinlock_t kstat_lock;
static struct list_head kstat_list;
static kid_t kstat_id;

static void
kstat_seq_show_headers(struct seq_file *f)
{
        kstat_t *ksp = (kstat_t *)f->private;
        ASSERT(ksp->ks_magic == KS_MAGIC);

        seq_printf(f, "%d %d 0x%02x %d %d %lld %lld\n",
		   ksp->ks_kid, ksp->ks_type, ksp->ks_flags,
		   ksp->ks_ndata, (int)ksp->ks_data_size,
		   ksp->ks_crtime, ksp->ks_snaptime);

	switch (ksp->ks_type) {
                case KSTAT_TYPE_RAW:
                        seq_printf(f, "raw data");
                        break;
                case KSTAT_TYPE_NAMED:
                        seq_printf(f, "%-31s %-4s %s\n",
                                   "name", "type", "data");
                        break;
                case KSTAT_TYPE_INTR:
                        seq_printf(f, "%-8s %-8s %-8s %-8s %-8s\n",
                                   "hard", "soft", "watchdog",
                                   "spurious", "multsvc");
                        break;
                case KSTAT_TYPE_IO:
                        seq_printf(f,
                                   "%-8s %-8s %-8s %-8s %-8s %-8s "
                                   "%-8s %-8s %-8s %-8s %-8s %-8s\n",
                                   "nread", "nwritten", "reads", "writes",
                                   "wtime", "wlentime", "wupdate",
                                   "rtime", "rlentime", "rupdate",
                                   "wcnt", "rcnt");
                        break;
                case KSTAT_TYPE_TIMER:
                        seq_printf(f,
                                   "%-31s %-8s "
                                   "%-8s %-8s %-8s %-8s %-8s\n",
                                   "name", "events", "elapsed",
                                   "min", "max", "start", "stop");
                        break;
                default:
                        PANIC("Undefined kstat type %d\n", ksp->ks_type);
        }
}

static int
kstat_seq_show_raw(struct seq_file *f, unsigned char *p, int l)
{
        int i, j;

        for (i = 0; ; i++) {
                seq_printf(f, "%03x:", i);

                for (j = 0; j < 16; j++) {
                        if (i * 16 + j >= l) {
                                seq_printf(f, "\n");
                                goto out;
                        }

                        seq_printf(f, " %02x", (unsigned char)p[i * 16 + j]);
                }
                seq_printf(f, "\n");
        }
out:
        return 0;
}

static int
kstat_seq_show_named(struct seq_file *f, kstat_named_t *knp)
{
        seq_printf(f, "%-31s %-4d ", knp->name, knp->data_type);

        switch (knp->data_type) {
                case KSTAT_DATA_CHAR:
                        knp->value.c[15] = '\0'; /* NULL terminate */
                        seq_printf(f, "%-16s", knp->value.c);
                        break;
                /* XXX - We need to be more careful able what tokens are
                 * used for each arch, for now this is correct for x86_64.
                 */
                case KSTAT_DATA_INT32:
                        seq_printf(f, "%d", knp->value.i32);
                        break;
                case KSTAT_DATA_UINT32:
                        seq_printf(f, "%u", knp->value.ui32);
                        break;
                case KSTAT_DATA_INT64:
                        seq_printf(f, "%lld", (signed long long)knp->value.i64);
                        break;
                case KSTAT_DATA_UINT64:
                        seq_printf(f, "%llu", (unsigned long long)knp->value.ui64);
                        break;
                case KSTAT_DATA_LONG:
                        seq_printf(f, "%ld", knp->value.l);
                        break;
                case KSTAT_DATA_ULONG:
                        seq_printf(f, "%lu", knp->value.ul);
                        break;
                case KSTAT_DATA_STRING:
                        KSTAT_NAMED_STR_PTR(knp)
                                [KSTAT_NAMED_STR_BUFLEN(knp)-1] = '\0';
                        seq_printf(f, "%s", KSTAT_NAMED_STR_PTR(knp));
                        break;
                default:
                        PANIC("Undefined kstat data type %d\n", knp->data_type);
        }

        seq_printf(f, "\n");

        return 0;
}

static int
kstat_seq_show_intr(struct seq_file *f, kstat_intr_t *kip)
{
        seq_printf(f, "%-8u %-8u %-8u %-8u %-8u\n",
                   kip->intrs[KSTAT_INTR_HARD],
                   kip->intrs[KSTAT_INTR_SOFT],
                   kip->intrs[KSTAT_INTR_WATCHDOG],
                   kip->intrs[KSTAT_INTR_SPURIOUS],
                   kip->intrs[KSTAT_INTR_MULTSVC]);

        return 0;
}

static int
kstat_seq_show_io(struct seq_file *f, kstat_io_t *kip)
{
        seq_printf(f,
                   "%-8llu %-8llu %-8u %-8u %-8lld %-8lld "
                   "%-8lld %-8lld %-8lld %-8lld %-8u %-8u\n",
                   kip->nread, kip->nwritten,
                   kip->reads, kip->writes,
                   kip->wtime, kip->wlentime, kip->wlastupdate,
                   kip->rtime, kip->wlentime, kip->rlastupdate,
                   kip->wcnt,  kip->rcnt);

        return 0;
}

static int
kstat_seq_show_timer(struct seq_file *f, kstat_timer_t *ktp)
{
        seq_printf(f,
                   "%-31s %-8llu %-8lld %-8lld %-8lld %-8lld %-8lld\n",
                   ktp->name, ktp->num_events, ktp->elapsed_time,
                   ktp->min_time, ktp->max_time,
                   ktp->start_time, ktp->stop_time);

        return 0;
}

static int
kstat_seq_show(struct seq_file *f, void *p)
{
        kstat_t *ksp = (kstat_t *)f->private;
        int rc = 0;

        ASSERT(ksp->ks_magic == KS_MAGIC);

	switch (ksp->ks_type) {
                case KSTAT_TYPE_RAW:
                        ASSERT(ksp->ks_ndata == 1);
                        rc = kstat_seq_show_raw(f, ksp->ks_data,
                                                ksp->ks_data_size);
                        break;
                case KSTAT_TYPE_NAMED:
                        rc = kstat_seq_show_named(f, (kstat_named_t *)p);
                        break;
                case KSTAT_TYPE_INTR:
                        rc = kstat_seq_show_intr(f, (kstat_intr_t *)p);
                        break;
                case KSTAT_TYPE_IO:
                        rc = kstat_seq_show_io(f, (kstat_io_t *)p);
                        break;
                case KSTAT_TYPE_TIMER:
                        rc = kstat_seq_show_timer(f, (kstat_timer_t *)p);
                        break;
                default:
                        PANIC("Undefined kstat type %d\n", ksp->ks_type);
        }

        return rc;
}

int
kstat_default_update(kstat_t *ksp, int rw)
{
	ASSERT(ksp != NULL);
	return 0;
}

static void *
kstat_seq_data_addr(kstat_t *ksp, loff_t n)
{
        void *rc = NULL;
        SENTRY;

	switch (ksp->ks_type) {
                case KSTAT_TYPE_RAW:
	                rc = ksp->ks_data;
                        break;
                case KSTAT_TYPE_NAMED:
                        rc = ksp->ks_data + n * sizeof(kstat_named_t);
                        break;
                case KSTAT_TYPE_INTR:
                        rc = ksp->ks_data + n * sizeof(kstat_intr_t);
                        break;
                case KSTAT_TYPE_IO:
                        rc = ksp->ks_data + n * sizeof(kstat_io_t);
                        break;
                case KSTAT_TYPE_TIMER:
                        rc = ksp->ks_data + n * sizeof(kstat_timer_t);
                        break;
                default:
                        PANIC("Undefined kstat type %d\n", ksp->ks_type);
        }

        SRETURN(rc);
}

static void *
kstat_seq_start(struct seq_file *f, loff_t *pos)
{
        loff_t n = *pos;
        kstat_t *ksp = (kstat_t *)f->private;
        ASSERT(ksp->ks_magic == KS_MAGIC);
        SENTRY;

        /* Dynamically update kstat, on error existing kstats are used */
        (void) ksp->ks_update(ksp, KSTAT_READ);

        spin_lock(&ksp->ks_lock);
	ksp->ks_snaptime = gethrtime();

        if (!n)
                kstat_seq_show_headers(f);

        if (n >= ksp->ks_ndata)
                SRETURN(NULL);

        SRETURN(kstat_seq_data_addr(ksp, n));
}

static void *
kstat_seq_next(struct seq_file *f, void *p, loff_t *pos)
{
        kstat_t *ksp = (kstat_t *)f->private;
        ASSERT(ksp->ks_magic == KS_MAGIC);
        SENTRY;

        ++*pos;
        if (*pos >= ksp->ks_ndata)
                SRETURN(NULL);

        SRETURN(kstat_seq_data_addr(ksp, *pos));
}

static void
kstat_seq_stop(struct seq_file *f, void *v)
{
        kstat_t *ksp = (kstat_t *)f->private;
        ASSERT(ksp->ks_magic == KS_MAGIC);

        spin_unlock(&ksp->ks_lock);
}

static struct seq_operations kstat_seq_ops = {
        .show  = kstat_seq_show,
        .start = kstat_seq_start,
        .next  = kstat_seq_next,
        .stop  = kstat_seq_stop,
};

static int
proc_kstat_open(struct inode *inode, struct file *filp)
{
        struct seq_file *f;
        int rc;

        rc = seq_open(filp, &kstat_seq_ops);
        if (rc)
                return rc;

        f = filp->private_data;
        f->private = PDE(inode)->data;

        return rc;
}

static struct file_operations proc_kstat_operations = {
        .open           = proc_kstat_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

kstat_t *
__kstat_create(const char *ks_module, int ks_instance, const char *ks_name,
             const char *ks_class, uchar_t ks_type, uint_t ks_ndata,
             uchar_t ks_flags)
{
	kstat_t *ksp;

	ASSERT(ks_module);
	ASSERT(ks_instance == 0);
	ASSERT(ks_name);
	ASSERT(!(ks_flags & KSTAT_FLAG_UNSUPPORTED));

	if ((ks_type == KSTAT_TYPE_INTR) || (ks_type == KSTAT_TYPE_IO))
                ASSERT(ks_ndata == 1);

	ksp = kmem_zalloc(sizeof(*ksp), KM_SLEEP);
	if (ksp == NULL)
		return ksp;

	spin_lock(&kstat_lock);
	ksp->ks_kid = kstat_id;
        kstat_id++;
	spin_unlock(&kstat_lock);

        ksp->ks_magic = KS_MAGIC;
	spin_lock_init(&ksp->ks_lock);
	INIT_LIST_HEAD(&ksp->ks_list);

	ksp->ks_crtime = gethrtime();
        ksp->ks_snaptime = ksp->ks_crtime;
	strncpy(ksp->ks_module, ks_module, KSTAT_STRLEN);
	ksp->ks_instance = ks_instance;
	strncpy(ksp->ks_name, ks_name, KSTAT_STRLEN);
	strncpy(ksp->ks_class, ks_class, KSTAT_STRLEN);
	ksp->ks_type = ks_type;
	ksp->ks_flags = ks_flags;
	ksp->ks_update = kstat_default_update;
	ksp->ks_private = NULL;

	switch (ksp->ks_type) {
                case KSTAT_TYPE_RAW:
	                ksp->ks_ndata = 1;
                        ksp->ks_data_size = ks_ndata;
                        break;
                case KSTAT_TYPE_NAMED:
	                ksp->ks_ndata = ks_ndata;
                        ksp->ks_data_size = ks_ndata * sizeof(kstat_named_t);
                        break;
                case KSTAT_TYPE_INTR:
	                ksp->ks_ndata = ks_ndata;
                        ksp->ks_data_size = ks_ndata * sizeof(kstat_intr_t);
                        break;
                case KSTAT_TYPE_IO:
	                ksp->ks_ndata = ks_ndata;
                        ksp->ks_data_size = ks_ndata * sizeof(kstat_io_t);
                        break;
                case KSTAT_TYPE_TIMER:
	                ksp->ks_ndata = ks_ndata;
                        ksp->ks_data_size = ks_ndata * sizeof(kstat_timer_t);
                        break;
                default:
                        PANIC("Undefined kstat type %d\n", ksp->ks_type);
        }

	if (ksp->ks_flags & KSTAT_FLAG_VIRTUAL) {
                ksp->ks_data = NULL;
        } else {
                ksp->ks_data = kmem_alloc(ksp->ks_data_size, KM_SLEEP);
                if (ksp->ks_data == NULL) {
                        kmem_free(ksp, sizeof(*ksp));
                        ksp = NULL;
                }
        }

	return ksp;
}
EXPORT_SYMBOL(__kstat_create);

void
__kstat_install(kstat_t *ksp)
{
	struct proc_dir_entry *de_module, *de_name;
	kstat_t *tmp;
	int rc = 0;
	SENTRY;

	spin_lock(&kstat_lock);

	/* Item may only be added to the list once */
        list_for_each_entry(tmp, &kstat_list, ks_list) {
                if (tmp == ksp) {
		        spin_unlock(&kstat_lock);
			SGOTO(out, rc = -EEXIST);
		}
	}

        list_add_tail(&ksp->ks_list, &kstat_list);
	spin_unlock(&kstat_lock);

	de_module = proc_dir_entry_find(proc_spl_kstat, ksp->ks_module);
	if (de_module == NULL) {
                de_module = proc_mkdir(ksp->ks_module, proc_spl_kstat);
		if (de_module == NULL)
			SGOTO(out, rc = -EUNATCH);
	}

	de_name = create_proc_entry(ksp->ks_name, 0444, de_module);
	if (de_name == NULL)
		SGOTO(out, rc = -EUNATCH);

	spin_lock(&ksp->ks_lock);
	ksp->ks_proc = de_name;
	de_name->proc_fops = &proc_kstat_operations;
        de_name->data = (void *)ksp;
	spin_unlock(&ksp->ks_lock);
out:
	if (rc) {
		spin_lock(&kstat_lock);
	        list_del_init(&ksp->ks_list);
		spin_unlock(&kstat_lock);
	}

	SEXIT;
}
EXPORT_SYMBOL(__kstat_install);

void
__kstat_delete(kstat_t *ksp)
{
	struct proc_dir_entry *de_module;

	spin_lock(&kstat_lock);
        list_del_init(&ksp->ks_list);
	spin_unlock(&kstat_lock);

        if (ksp->ks_proc) {
	        de_module = ksp->ks_proc->parent;
	        remove_proc_entry(ksp->ks_name, de_module);

	        /* Remove top level module directory if it's empty */
	        if (proc_dir_entries(de_module) == 0)
		        remove_proc_entry(de_module->name, de_module->parent);
	}

	if (!(ksp->ks_flags & KSTAT_FLAG_VIRTUAL))
                kmem_free(ksp->ks_data, ksp->ks_data_size);

	kmem_free(ksp, sizeof(*ksp));

	return;
}
EXPORT_SYMBOL(__kstat_delete);

int
spl_kstat_init(void)
{
	SENTRY;
	spin_lock_init(&kstat_lock);
	INIT_LIST_HEAD(&kstat_list);
        kstat_id = 0;
	SRETURN(0);
}

void
spl_kstat_fini(void)
{
	SENTRY;
	ASSERT(list_empty(&kstat_list));
	SEXIT;
}