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/* $Id: plugin_diskstats.c,v 1.8 2005/05/08 04:32:44 reinelt Exp $
 *
 * plugin for /proc/diskstats parsing
 *
 * Copyright (C) 2003 Michael Reinelt <reinelt@eunet.at>
 * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * This file is part of LCD4Linux.
 *
 * LCD4Linux 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, or (at your option)
 * any later version.
 *
 * LCD4Linux 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 this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 * $Log: plugin_diskstats.c,v $
 * Revision 1.8  2005/05/08 04:32:44  reinelt
 * CodingStyle added and applied
 *
 * Revision 1.7  2005/01/18 06:30:23  reinelt
 * added (C) to all copyright statements
 *
 * Revision 1.6  2004/06/26 12:05:00  reinelt
 *
 * uh-oh... the last CVS log message messed up things a lot...
 *
 * Revision 1.5  2004/06/26 09:27:21  reinelt
 *
 * added '-W' to CFLAGS
 * changed all C++ comments to C ones
 * cleaned up a lot of signed/unsigned mistakes
 *
 * Revision 1.4  2004/06/17 10:58:58  reinelt
 *
 * changed plugin_netdev to use the new fast hash model
 *
 * Revision 1.3  2004/06/17 06:23:43  reinelt
 *
 * hash handling rewritten to solve performance issues
 *
 * Revision 1.2  2004/05/29 01:07:56  reinelt
 * bug in plugin_diskstats fixed
 *
 * Revision 1.1  2004/05/29 00:27:23  reinelt
 *
 * added plugin_diskstats.c
 *
 */

/* 
 * exported functions:
 *
 * int plugin_init_diskstats (void)
 *  adds functions to access /proc/stat
 *
 */


#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include "debug.h"
#include "plugin.h"
#include "hash.h"


static HASH DISKSTATS;
static FILE *stream = NULL;


static int parse_diskstats(void)
{
    int age;

    /* reread every 10 msec only */
    age = hash_age(&DISKSTATS, NULL);
    if (age > 0 && age <= 10)
	return 0;

    if (stream == NULL)
	stream = fopen("/proc/diskstats", "r");
    if (stream == NULL) {
	error("fopen(/proc/diskstats) failed: %s", strerror(errno));
	return -1;
    }

    rewind(stream);

    while (!feof(stream)) {
	char buffer[1024];
	char dev[64];
	char *beg, *end;
	unsigned int num, len;

	if (fgets(buffer, sizeof(buffer), stream) == NULL)
	    break;

	/* fetch device name (3rd column) as key */
	num = 0;
	beg = buffer;
	end = beg;
	while (*beg) {
	    while (*beg == ' ')
		beg++;
	    end = beg + 1;
	    while (*end && *end != ' ')
		end++;
	    if (num++ == 2)
		break;
	    beg = end ? end + 1 : NULL;
	}
	len = end ? (unsigned) (end - beg) : strlen(beg);

	if (len >= sizeof(dev))
	    len = sizeof(dev) - 1;
	strncpy(dev, beg, len);
	dev[len] = '\0';

	hash_put_delta(&DISKSTATS, dev, buffer);

    }
    return 0;
}


static void my_diskstats(RESULT * result, RESULT * arg1, RESULT * arg2, RESULT * arg3)
{
    char *dev, *key;
    int delay;
    double value;

    if (parse_diskstats() < 0) {
	SetResult(&result, R_STRING, "");
	return;
    }

    dev = R2S(arg1);
    key = R2S(arg2);
    delay = R2N(arg3);

    value = hash_get_regex(&DISKSTATS, dev, key, delay);

    SetResult(&result, R_NUMBER, &value);
}


int plugin_init_diskstats(void)
{
    int i;
    char *header[] = { "major", "minor", "name",
	"reads", "read_merges", "read_sectors", "read_ticks",
	"writes", "write_merges", "write_sectors", "write_ticks",
	"in_flight", "io_ticks", "time_in_queue", ""
    };

    hash_create(&DISKSTATS);
    hash_set_delimiter(&DISKSTATS, " \n");
    for (i = 0; *header[i] != '\0'; i++) {
	hash_set_column(&DISKSTATS, i, header[i]);
    }

    AddFunction("diskstats", 3, my_diskstats);
    return 0;
}

void plugin_exit_diskstats(void)
{
    if (stream != NULL) {
	fclose(stream);
	stream = NULL;
    }
    hash_destroy(&DISKSTATS);
}
pan> HASH_ITEM *ha = (HASH_ITEM *) a; HASH_ITEM *hb = (HASH_ITEM *) b; return strcasecmp(ha->key, hb->key); } /* bsearch compare function for hash headers */ static int hash_lookup_column(const void *a, const void *b) { char *key = (char *) a; HASH_COLUMN *column = (HASH_COLUMN *) b; return strcasecmp(key, column->key); } /* qsort compare function for hash headers */ static int hash_sort_column(const void *a, const void *b) { HASH_COLUMN *ha = (HASH_COLUMN *) a; HASH_COLUMN *hb = (HASH_COLUMN *) b; return strcasecmp(ha->key, hb->key); } /* split a value into columns and */ /* return the nth column in a string */ /* WARNING: does return a pointer to a static string!! */ static char *split(const char *val, const int column, const char *delimiter) { static char buffer[256]; int num; size_t len; const char *beg, *end; if (column < 0) return (char *) val; if (val == NULL) return NULL; num = 0; len = 0; beg = val; end = beg; while (beg && *beg) { while (strchr(delimiter, *beg)) beg++; end = strpbrk(beg, delimiter); if (num++ == column) break; beg = end ? end + 1 : NULL; } if (beg != NULL) { len = end ? (size_t) (end - beg) : strlen(beg); if (len >= sizeof(buffer)) len = sizeof(buffer) - 1; strncpy(buffer, beg, len); } buffer[len] = '\0'; return buffer; } /* search an entry in the hash table: */ /* If the table is flagged "sorted", the entry is looked */ /* up using the bsearch function. If the table is */ /* unsorted, it will be searched in a linear way */ static HASH_ITEM *hash_lookup(HASH * Hash, const char *key, const int do_sort) { HASH_ITEM *Item = NULL; /* maybe sort the array */ if (do_sort && !Hash->sorted) { qsort(Hash->Items, Hash->nItems, sizeof(HASH_ITEM), hash_sort_item); Hash->sorted = 1; } /* no key was passed */ if (key == NULL) return NULL; /* lookup using bsearch */ if (Hash->sorted) { Item = bsearch(key, Hash->Items, Hash->nItems, sizeof(HASH_ITEM), hash_lookup_item); } /* linear search */ if (Item == NULL) { int i; for (i = 0; i < Hash->nItems; i++) { if (strcmp(key, Hash->Items[i].key) == 0) { Item = &(Hash->Items[i]); break; } } } return Item; } /* return the age in milliseconds of an entry from the hash table */ /* or from the hash table itself if key is NULL */ /* returns -1 if entry does not exist */ int hash_age(HASH * Hash, const char *key) { HASH_ITEM *Item; struct timeval now, *timestamp; if (key == NULL) { timestamp = &(Hash->timestamp); } else { Item = hash_lookup(Hash, key, 1); if (Item == NULL) return -1; timestamp = &(Item->Slot[Item->index].timestamp); } gettimeofday(&now, NULL); return (now.tv_sec - timestamp->tv_sec) * 1000 + (now.tv_usec - timestamp->tv_usec) / 1000; } /* add an entry to the column header table */ void hash_set_column(HASH * Hash, const int number, const char *column) { if (Hash == NULL) return; Hash->nColumns++; Hash->Columns = realloc(Hash->Columns, Hash->nColumns * sizeof(HASH_COLUMN)); Hash->Columns[Hash->nColumns - 1].key = strdup(column); Hash->Columns[Hash->nColumns - 1].val = number; qsort(Hash->Columns, Hash->nColumns, sizeof(HASH_COLUMN), hash_sort_column); } /* fetch a column number by column header */ static int hash_get_column(HASH * Hash, const char *key) { HASH_COLUMN *Column; if (key == NULL || *key == '\0') return -1; Column = bsearch(key, Hash->Columns, Hash->nColumns, sizeof(HASH_COLUMN), hash_lookup_column); if (Column == NULL) return -1; return Column->val; } /* set column delimiters */ void hash_set_delimiter(HASH * Hash, const char *delimiter) { if (Hash->delimiter != NULL) free(Hash->delimiter); Hash->delimiter = strdup(delimiter); } /* get a string from the hash table */ char *hash_get(HASH * Hash, const char *key, const char *column) { HASH_ITEM *Item; int c; Item = hash_lookup(Hash, key, 1); if (Item == NULL) return NULL; c = hash_get_column(Hash, column); return split(Item->Slot[Item->index].value, c, Hash->delimiter); } /* get a delta value from the delta table */ double hash_get_delta(HASH * Hash, const char *key, const char *column, const int delay) { HASH_ITEM *Item; HASH_SLOT *Slot1, *Slot2; int i, c; double v1, v2; double dv, dt; struct timeval now, end; /* lookup item */ Item = hash_lookup(Hash, key, 1); if (Item == NULL) return 0.0; /* this is the "current" Slot */ Slot1 = &(Item->Slot[Item->index]); /* fetch column number */ c = hash_get_column(Hash, column); /* if delay is zero, return absolute value */ if (delay == 0) return atof(split(Slot1->value, c, Hash->delimiter)); /* prepare timing values */ now = Slot1->timestamp; end.tv_sec = now.tv_sec; end.tv_usec = now.tv_usec - 1000 * delay; while (end.tv_usec < 0) { end.tv_sec--; end.tv_usec += 1000000; } /* search delta slot */ Slot2 = &(Item->Slot[Item->index]); for (i = 1; i < Item->nSlot; i++) { Slot2 = &(Item->Slot[(Item->index + i) % Item->nSlot]); if (Slot2->timestamp.tv_sec == 0) break; if (timercmp(&(Slot2->timestamp), &end, <)) break; } /* empty slot => try the one before */ if (Slot2->timestamp.tv_sec == 0) { i--; Slot2 = &(Item->Slot[(Item->index + i) % Item->nSlot]); } /* not enough slots available... */ if (i == 0) return 0.0; /* delta value, delta time */ v1 = atof(split(Slot1->value, c, Hash->delimiter)); v2 = atof(split(Slot2->value, c, Hash->delimiter)); dv = v1 - v2; dt = (Slot1->timestamp.tv_sec - Slot2->timestamp.tv_sec) + (Slot1->timestamp.tv_usec - Slot2->timestamp.tv_usec) / 1000000.0; if (dt > 0.0 && dv >= 0.0) return dv / dt; return 0.0; } /* get a delta value from the delta table */ /* key may contain regular expressions, and the sum */ /* of all matching entries is returned. */ double hash_get_regex(HASH * Hash, const char *key, const char *column, const int delay) { double sum; regex_t preg; int i, err; err = regcomp(&preg, key, REG_ICASE | REG_NOSUB); if (err != 0) { char buffer[32]; regerror(err, &preg, buffer, sizeof(buffer)); error("error in regular expression: %s", buffer); regfree(&preg); return 0.0; } /* force the table to be sorted by requesting anything */ hash_lookup(Hash, NULL, 1); sum = 0.0; for (i = 0; i < Hash->nItems; i++) { if (regexec(&preg, Hash->Items[i].key, 0, NULL, 0) == 0) { sum += hash_get_delta(Hash, Hash->Items[i].key, column, delay); } } regfree(&preg); return sum; } /* insert a key/val pair into the hash table */ /* If the entry does already exist, it will be overwritten, */ /* and the table stays sorted (if it has been before). */ /* Otherwise, the entry is appended at the end, and */ /* the table will be flagged 'unsorted' afterwards */ static HASH_ITEM *hash_set(HASH * Hash, const char *key, const char *value, const int delta) { HASH_ITEM *Item; HASH_SLOT *Slot; int size; Item = hash_lookup(Hash, key, 0); if (Item == NULL) { /* add entry */ Hash->sorted = 0; Hash->nItems++; Hash->Items = realloc(Hash->Items, Hash->nItems * sizeof(HASH_ITEM)); Item = &(Hash->Items[Hash->nItems - 1]); Item->key = strdup(key); Item->index = 0; Item->nSlot = delta; Item->Slot = malloc(Item->nSlot * sizeof(HASH_SLOT)); memset(Item->Slot, 0, Item->nSlot * sizeof(HASH_SLOT)); } else { /* maybe enlarge delta table */ if (Item->nSlot < delta) { Item->nSlot = delta; Item->Slot = realloc(Item->Slot, Item->nSlot * sizeof(HASH_SLOT)); } } if (Item->nSlot > 1) { /* move the pointer to the next free slot, wrap around if necessary */ if (--Item->index < 0) Item->index = Item->nSlot - 1; } /* create entry */ Slot = &(Item->Slot[Item->index]); size = strlen(value) + 1; /* maybe enlarge value buffer */ if (size > Slot->size) { /* buffer is either empty or too small */ /* allocate memory in multiples of CHUNK_SIZE */ Slot->size = CHUNK_SIZE * (size / CHUNK_SIZE + 1); Slot->value = realloc(Slot->value, Slot->size); } /* set value */ strcpy(Slot->value, value); /* set timestamps */ gettimeofday(&(Hash->timestamp), NULL); Slot->timestamp = Hash->timestamp; return Item; } /* insert a string into the hash table */ /* without delta processing */ void hash_put(HASH * Hash, const char *key, const char *value) { hash_set(Hash, key, value, 1); } /* insert a string into the hash table */ /* with delta processing */ void hash_put_delta(HASH * Hash, const char *key, const char *value) { hash_set(Hash, key, value, DELTA_SLOTS); } void hash_destroy(HASH * Hash) { int i; if (Hash->Items) { /* free all headers */ for (i = 0; i < Hash->nColumns; i++) { if (Hash->Columns[i].key) free(Hash->Columns[i].key); } /* free header table */ free(Hash->Columns); /* free all items */ for (i = 0; i < Hash->nItems; i++) { if (Hash->Items[i].key) free(Hash->Items[i].key); if (Hash->Items[i].Slot) free(Hash->Items[i].Slot); } /* free items table */ free(Hash->Items); } Hash->sorted = 0; Hash->nItems = 0; Hash->Items = NULL; }