src/libstatgrab/disk_stats.c

/*
 * i-scream libstatgrab
 * http://www.i-scream.org
 * Copyright (C) 2000-2004 i-scream
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307 USA
 *
 * $Id: disk_stats.c,v 1.66 2004/04/07 19:26:16 tdb Exp $
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "statgrab.h"
#include "vector.h"
#include "tools.h"

#ifdef SOLARIS
#include <sys/mnttab.h>
#include <sys/statvfs.h>
#include <kstat.h>
#define VALID_FS_TYPES {"ufs", "tmpfs"}
#endif

#if defined(LINUX) || defined(CYGWIN)
#include <mntent.h>
#include <sys/vfs.h>
#endif

#ifdef LINUX
#define VALID_FS_TYPES {"adfs", "affs", "befs", "bfs", "efs", "ext2", \
                        "ext3", "vxfs", "hfs", "hfsplus", "hpfs", "jffs", \
                        "jffs2", "minix", "msdos", "ntfs", "qnx4", "ramfs", \
                        "rootfs", "reiserfs", "sysv", "v7", "udf", "ufs", \
                        "umsdos", "vfat", "xfs", "jfs"}
#endif

#ifdef CYGWIN
#define VALID_FS_TYPES {"user"}
#endif

#ifdef ALLBSD
#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>
#endif
#if defined(FREEBSD) || defined(DFBSD)
#include <sys/dkstat.h>
#include <devstat.h>
#define VALID_FS_TYPES {"hpfs", "msdosfs", "ntfs", "udf", "ext2fs", \
                        "ufs", "mfs"}
#endif
#if defined(NETBSD) || defined(OPENBSD)
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/disk.h>
#define VALID_FS_TYPES {"ffs", "mfs", "msdos", "lfs", "adosfs", "ext2fs", \
                        "ntfs"}
#endif

static void disk_stat_init(sg_fs_stats *d) {
        d->device_name = NULL;
        d->fs_type = NULL;
        d->mnt_point = NULL;
}

static void disk_stat_destroy(sg_fs_stats *d) {
        free(d->device_name);
        free(d->fs_type);
        free(d->mnt_point);
}

static int is_valid_fs_type(const char *type) {
        const char *types[] = VALID_FS_TYPES;
        int i;

        for (i = 0; i < (sizeof types / sizeof *types); i++) {
                if (strcmp(types[i], type) == 0) {
                        return 1;
                }
        }
        return 0;
}

sg_fs_stats *sg_get_fs_stats(int *entries){
        VECTOR_DECLARE_STATIC(disk_stats, sg_fs_stats, 10,
                              disk_stat_init, disk_stat_destroy);

        int valid_type;
        int num_disks=0;
#if defined(LINUX) || defined (SOLARIS) || defined(CYGWIN)
        FILE *f;
#endif

        sg_fs_stats *disk_ptr;

#ifdef SOLARIS
        struct mnttab mp;
        struct statvfs fs;
#endif
#if defined(LINUX) || defined(CYGWIN)
        struct mntent *mp;
        struct statfs fs;
#endif
#ifdef ALLBSD
        int nummnt;
        struct statfs *mp;
#endif

#ifdef ALLBSD
        nummnt=getmntinfo(&mp , MNT_LOCAL);
        if (nummnt<=0){
                sg_set_error(SG_ERROR_GETMNTINFO, NULL);
                return NULL;
        }
        for(;nummnt--; mp++){
                valid_type = is_valid_fs_type(mp->f_fstypename);
#endif

#if defined(LINUX) || defined(CYGWIN)
        if ((f=setmntent("/etc/mtab", "r" ))==NULL){
                sg_set_error(SG_ERROR_SETMNTENT, NULL);
                return NULL;
        }

        while((mp=getmntent(f))){
                if((statfs(mp->mnt_dir, &fs)) !=0){
                        continue;
                }       

                valid_type = is_valid_fs_type(mp->mnt_type);
#endif

#ifdef SOLARIS
        if ((f=fopen("/etc/mnttab", "r" ))==NULL){
                sg_set_error(SG_ERROR_OPEN, "/etc/mnttab");
                return NULL;
        }
        while((getmntent(f, &mp)) == 0){
                if ((statvfs(mp.mnt_mountp, &fs)) !=0){
                        continue;
                }
                valid_type = is_valid_fs_type(mp.mnt_fstype);
#endif

                if(valid_type){
                        if (VECTOR_RESIZE(disk_stats, num_disks + 1) < 0) {
                                return NULL;
                        }
                        disk_ptr=disk_stats+num_disks;

#ifdef ALLBSD
                        if (sg_update_string(&disk_ptr->device_name, mp->f_mntfromname) < 0) {
                                return NULL;
                        }
                        if (sg_update_string(&disk_ptr->fs_type, mp->f_fstypename) < 0) {
                                return NULL;
                        }
                        if (sg_update_string(&disk_ptr->mnt_point, mp->f_mntonname) < 0) {
                                return NULL;
                        }

                        disk_ptr->size = (long long)mp->f_bsize * (long long) mp->f_blocks;
                        disk_ptr->avail = (long long)mp->f_bsize * (long long) mp->f_bavail;
                        disk_ptr->used = (disk_ptr->size) - ((long long)mp->f_bsize * (long long)mp->f_bfree);

                        disk_ptr->total_inodes=(long long)mp->f_files;
                        disk_ptr->free_inodes=(long long)mp->f_ffree;
                        /* Freebsd doesn't have a "available" inodes */
                        disk_ptr->used_inodes=disk_ptr->total_inodes-disk_ptr->free_inodes;
#endif
#if defined(LINUX) || defined(CYGWIN)
                        if (sg_update_string(&disk_ptr->device_name, mp->mnt_fsname) < 0) {
                                return NULL;
                        }
                                
                        if (sg_update_string(&disk_ptr->fs_type, mp->mnt_type) < 0) {   
                                return NULL;
                        }

                        if (sg_update_string(&disk_ptr->mnt_point, mp->mnt_dir) < 0) {
                                return NULL;
                        }
                        disk_ptr->size = (long long)fs.f_bsize * (long long)fs.f_blocks;
                        disk_ptr->avail = (long long)fs.f_bsize * (long long)fs.f_bavail;
                        disk_ptr->used = (disk_ptr->size) - ((long long)fs.f_bsize * (long long)fs.f_bfree);

                        disk_ptr->total_inodes=(long long)fs.f_files;
                        disk_ptr->free_inodes=(long long)fs.f_ffree;
                        /* Linux doesn't have a "available" inodes */
                        disk_ptr->used_inodes=disk_ptr->total_inodes-disk_ptr->free_inodes;
#endif

#ifdef SOLARIS
                        /* Maybe make this char[bigenough] and do strncpy's and put a null in the end? 
                         * Downside is its a bit hungry for a lot of mounts, as MNT_MAX_SIZE would prob 
                         * be upwards of a k each 
                         */
                        if (sg_update_string(&disk_ptr->device_name, mp.mnt_special) < 0) {
                                return NULL;
                        }

                        if (sg_update_string(&disk_ptr->fs_type, mp.mnt_fstype) < 0) {
                                return NULL;
                        }
        
                        if (sg_update_string(&disk_ptr->mnt_point, mp.mnt_mountp) < 0) {
                                return NULL;
                        }
                        
                        disk_ptr->size = (long long)fs.f_frsize * (long long)fs.f_blocks;
                        disk_ptr->avail = (long long)fs.f_frsize * (long long)fs.f_bavail;
                        disk_ptr->used = (disk_ptr->size) - ((long long)fs.f_frsize * (long long)fs.f_bfree);
                
                        disk_ptr->total_inodes=(long long)fs.f_files;
                        disk_ptr->used_inodes=disk_ptr->total_inodes - (long long)fs.f_ffree;
                        disk_ptr->free_inodes=(long long)fs.f_favail;
#endif
                        num_disks++;
                }
        }

        *entries=num_disks;     

        /* If this fails, there is very little i can do about it, so
           I'll ignore it :) */
#if defined(LINUX) || defined(CYGWIN)
        endmntent(f);
#endif
#if defined(SOLARIS)
        fclose(f);
#endif

        return disk_stats;

}

int sg_fs_compare_device_name(const void *va, const void *vb) {
        const sg_fs_stats *a = (const sg_fs_stats *)va;
        const sg_fs_stats *b = (const sg_fs_stats *)vb;

        return strcmp(a->device_name, b->device_name);
}

int sg_fs_compare_mnt_point(const void *va, const void *vb) {
        const sg_fs_stats *a = (const sg_fs_stats *)va;
        const sg_fs_stats *b = (const sg_fs_stats *)vb;

        return strcmp(a->mnt_point, b->mnt_point);
}

static void diskio_stat_init(sg_disk_io_stats *d) {
        d->disk_name = NULL;
}

static void diskio_stat_destroy(sg_disk_io_stats *d) {
        free(d->disk_name);
}

VECTOR_DECLARE_STATIC(diskio_stats, sg_disk_io_stats, 10,
                      diskio_stat_init, diskio_stat_destroy);

#ifdef LINUX
typedef struct {
        int major;
        int minor;
} partition;
#endif

sg_disk_io_stats *sg_get_disk_io_stats(int *entries){
        int num_diskio;
#ifndef LINUX
        sg_disk_io_stats *diskio_stats_ptr;
#endif

#ifdef SOLARIS
        kstat_ctl_t *kc;
        kstat_t *ksp;
        kstat_io_t kios;
#endif
#ifdef LINUX
        FILE *f;
        char *line_ptr;
        int major, minor;
        int has_pp_stats = 1;
        VECTOR_DECLARE_STATIC(parts, partition, 16, NULL, NULL);
        int i, n;
        time_t now;
        const char *format;
#endif
#if defined(FREEBSD) || defined(DFBSD)
        static struct statinfo stats;
        static int stats_init = 0;
        int counter;
        struct device_selection *dev_sel = NULL;
        int n_selected, n_selections;
        long sel_gen;
        struct devstat *dev_ptr;
#endif
#ifdef NETBSD
        struct disk_sysctl *stats;
#endif
#ifdef OPENBSD
        int diskcount;
        char *disknames, *name, *bufpp;
        char **dk_name;
        struct diskstats *stats;
#endif
#ifdef NETBSD
#define MIBSIZE 3
#endif
#ifdef OPENBSD
#define MIBSIZE 2
#endif
#if defined(NETBSD) || defined(OPENBSD)
        int num_disks, i;
        int mib[MIBSIZE];
        size_t size;
#endif

        num_diskio=0;

#ifdef OPENBSD
        mib[0] = CTL_HW;
        mib[1] = HW_DISKCOUNT;

        size = sizeof(diskcount);
        if (sysctl(mib, MIBSIZE, &diskcount, &size, NULL, 0) < 0) {
                sg_error(SG_ERROR_SYSCTL, "CTL_HW.HW_DISKCOUNT");
                return NULL;
        }

        mib[0] = CTL_HW;
        mib[1] = HW_DISKNAMES;

        if (sysctl(mib, MIBSIZE, NULL, &size, NULL, 0) < 0) {
                sg_error(SG_ERROR_SYSCTL, "CTL_HW.HW_DISKNAMES");
                return NULL;
        }

        disknames = sg_malloc(size);
        if (disknames == NULL) {
                return NULL;
        }

        if (sysctl(mib, MIBSIZE, disknames, &size, NULL, 0) < 0) {
                sg_error(SG_ERROR_SYSCTL, "CTL_HW.HW_DISKNAMES");
                return NULL;
        }

        dk_name = sg_malloc(diskcount * sizeof(char *));
        bufpp = disknames;
        for (i = 0; i < diskcount && (name = strsep(&bufpp, ",")) != NULL; i++) {
                dk_name[i] = name;
        }
#endif

#if defined(NETBSD) || defined(OPENBSD)
        mib[0] = CTL_HW;
        mib[1] = HW_DISKSTATS;
#ifdef NETBSD
        mib[2] = sizeof(struct disk_sysctl);
#endif

        if (sysctl(mib, MIBSIZE, NULL, &size, NULL, 0) < 0) {
                sg_error(SG_ERROR_SYSCTL, "CTL_HW.HW_DISKSTATS");
                return NULL;
        }

#ifdef NETBSD
        num_disks = size / sizeof(struct disk_sysctl);
#else
        num_disks = size / sizeof(struct diskstats);
#endif

        stats = sg_malloc(size);
        if (stats == NULL) {
                return NULL;
        }

        if (sysctl(mib, MIBSIZE, stats, &size, NULL, 0) < 0) {
                sg_error(SG_ERROR_SYSCTL, "CTL_HW.HW_DISKSTATS");
                return NULL;
        }

        for (i = 0; i < num_disks; i++) {
                const char *name;
                u_int64_t rbytes, wbytes;

#ifdef NETBSD
#ifdef HAVE_DK_RBYTES
                rbytes = stats[i].dk_rbytes;
                wbytes = stats[i].dk_wbytes;
#else
                /* Before 1.7, NetBSD merged reads and writes. */
                rbytes = wbytes = stats[i].dk_bytes;
#endif
#else
                rbytes = wbytes = stats[i].ds_bytes;
#endif

                /* Don't keep stats for disks that have never been used. */
                if (rbytes == 0 && wbytes == 0) {
                        continue;
                }

                if (VECTOR_RESIZE(diskio_stats, num_diskio + 1) < 0) {
                        return NULL;
                }
                diskio_stats_ptr = diskio_stats + num_diskio;
                
                diskio_stats_ptr->read_bytes = rbytes;
                diskio_stats_ptr->write_bytes = wbytes;
#ifdef NETBSD
                name = stats[i].dk_name;
#else
                name = dk_name[i];
#endif
                if (sg_update_string(&diskio_stats_ptr->disk_name, name) < 0) {
                        return NULL;
                }
                diskio_stats_ptr->systime = time(NULL);
        
                num_diskio++;   
        }

        free(stats);
#ifdef OPENBSD
        free(dk_name);
        free(disknames);
#endif
#endif

#if defined(FREEBSD) || defined(DFBSD)
        if (!stats_init) {
                stats.dinfo=sg_malloc(sizeof(struct devinfo));
                if(stats.dinfo==NULL) return NULL;
                bzero(stats.dinfo, sizeof(struct devinfo));
                stats_init = 1;
        }
#ifdef FREEBSD5
        if ((devstat_getdevs(NULL, &stats)) < 0) {
                sg_set_error(SG_ERROR_DEVSTAT_GETDEVS, NULL);
                return NULL;
        }
        /* Not aware of a get all devices, so i said 999. If we ever
         * find a machine with more than 999 disks, then i'll change
         * this number :)
         */
        if (devstat_selectdevs(&dev_sel, &n_selected, &n_selections, &sel_gen, stats.dinfo->generation, stats.dinfo->devices, stats.dinfo->numdevs, NULL, 0, NULL, 0, DS_SELECT_ONLY, 999, 1) < 0) {
                sg_set_error(SG_ERROR_DEVSTAT_SELECTDEVS, NULL);
                return NULL;
        }
#else
        if ((getdevs(&stats)) < 0) {
                sg_set_error(SG_ERROR_DEVSTAT_GETDEVS, NULL);
                return NULL;
        }
        /* Not aware of a get all devices, so i said 999. If we ever
         * find a machine with more than 999 disks, then i'll change
         * this number :)
         */
        if (selectdevs(&dev_sel, &n_selected, &n_selections, &sel_gen, stats.dinfo->generation, stats.dinfo->devices, stats.dinfo->numdevs, NULL, 0, NULL, 0, DS_SELECT_ONLY, 999, 1) < 0) {
                sg_set_error(SG_ERROR_DEVSTAT_SELECTDEVS, NULL);
                return NULL;
        }
#endif

        for(counter=0;counter<stats.dinfo->numdevs;counter++){
                dev_ptr=&stats.dinfo->devices[dev_sel[counter].position];

                /* Throw away devices that have done nothing, ever.. Eg "odd" 
                 * devices.. like mem, proc.. and also doesn't report floppy
                 * drives etc unless they are doing stuff :)
                 */
#ifdef FREEBSD5
                if((dev_ptr->bytes[DEVSTAT_READ]==0) && (dev_ptr->bytes[DEVSTAT_WRITE]==0)) continue;
#else
                if((dev_ptr->bytes_read==0) && (dev_ptr->bytes_written==0)) continue;
#endif

                if (VECTOR_RESIZE(diskio_stats, num_diskio + 1) < 0) {
                        return NULL;
                }
                diskio_stats_ptr=diskio_stats+num_diskio;

#ifdef FREEBSD5         
                diskio_stats_ptr->read_bytes=dev_ptr->bytes[DEVSTAT_READ];
                diskio_stats_ptr->write_bytes=dev_ptr->bytes[DEVSTAT_WRITE];
#else
                diskio_stats_ptr->read_bytes=dev_ptr->bytes_read;
                diskio_stats_ptr->write_bytes=dev_ptr->bytes_written;
#endif
                if(diskio_stats_ptr->disk_name!=NULL) free(diskio_stats_ptr->disk_name);
                if (asprintf((&diskio_stats_ptr->disk_name), "%s%d", dev_ptr->device_name, dev_ptr->unit_number) == -1) {
                        sg_set_error(SG_ERROR_ASPRINTF, NULL);
                        return NULL;
                }
                diskio_stats_ptr->systime=time(NULL);

                num_diskio++;
        }
        free(dev_sel);

#endif
#ifdef SOLARIS
        if ((kc = kstat_open()) == NULL) {
                sg_set_error(SG_ERROR_KSTAT_OPEN, NULL);
                return NULL;
        }

        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                if (!strcmp(ksp->ks_class, "disk")) {

                        if(ksp->ks_type != KSTAT_TYPE_IO) continue;
                        /* We dont want metadevices appearins as num_diskio */
                        if(strcmp(ksp->ks_module, "md")==0) continue;
                        if((kstat_read(kc, ksp, &kios))==-1){   
                        }
                        
                        if (VECTOR_RESIZE(diskio_stats, num_diskio + 1) < 0) {
                                kstat_close(kc);
                                return NULL;
                        }
                        diskio_stats_ptr=diskio_stats+num_diskio;
                        
                        diskio_stats_ptr->read_bytes=kios.nread;
                        diskio_stats_ptr->write_bytes=kios.nwritten;
                        if (sg_update_string(&diskio_stats_ptr->disk_name,
                                             sg_get_svr_from_bsd(ksp->ks_name)) < 0) {
                                return NULL;
                        }
                        diskio_stats_ptr->systime=time(NULL);

                        num_diskio++;
                }
        }

        kstat_close(kc);
#endif

#ifdef LINUX
        num_diskio = 0;
        n = 0;

        /* Read /proc/partitions to find what devices exist. Recent 2.4 kernels
           have statistics in here too, so we can use those directly.
           2.6 kernels have /proc/diskstats instead with almost (but not quite)
           the same format. */

        f = fopen("/proc/diskstats", "r");
        format = " %d %d %99s %*d %*d %lld %*d %*d %*d %lld";
        if (f == NULL) {
                f = fopen("/proc/partitions", "r");
                format = " %d %d %*d %99s %*d %*d %lld %*d %*d %*d %lld";
        }
        if (f == NULL) goto out;
        now = time(NULL);

        while ((line_ptr = sg_f_read_line(f, "")) != NULL) {
                char name[100];
                char *s;
                long long rsect, wsect;

                int nr = sscanf(line_ptr, format,
                        &major, &minor, name, &rsect, &wsect);
                if (nr < 3) continue;

                /* Skip device names ending in numbers, since they're
                   partitions. */
                s = name;
                while (*s != '\0') s++;
                --s;
                if (*s >= '0' && *s <= '9') continue;

                if (nr < 5) {
                        has_pp_stats = 0;
                        rsect = 0;
                        wsect = 0;
                }

                if (VECTOR_RESIZE(diskio_stats, n + 1) < 0) {
                        goto out;
                }
                if (VECTOR_RESIZE(parts, n + 1) < 0) {
                        goto out;
                }

                if (sg_update_string(&diskio_stats[n].disk_name, name) < 0) {
                        goto out;
                }
                diskio_stats[n].read_bytes = rsect * 512;
                diskio_stats[n].write_bytes = wsect * 512;
                diskio_stats[n].systime = now;
                parts[n].major = major;
                parts[n].minor = minor;

                n++;
        }

        fclose(f);
        f = NULL;

        if (!has_pp_stats) {
                /* This is an older kernel where /proc/partitions doesn't
                   contain stats. Read what we can from /proc/stat instead, and
                   fill in the appropriate bits of the list allocated above. */

                f = fopen("/proc/stat", "r");
                if (f == NULL) goto out;
                now = time(NULL);
        
                line_ptr = sg_f_read_line(f, "disk_io:");
                if (line_ptr == NULL) goto out;
        
                while((line_ptr=strchr(line_ptr, ' '))!=NULL){
                        long long rsect, wsect;

                        if (*++line_ptr == '\0') break;
        
                        if((sscanf(line_ptr,
                                "(%d,%d):(%*d, %*d, %lld, %*d, %lld)",
                                &major, &minor, &rsect, &wsect)) != 4) {
                                        continue;
                        }

                        /* Find the corresponding device from earlier.
                           Just to add to the fun, "minor" is actually the disk
                           number, not the device minor, so we need to figure
                           out the real minor number based on the major!
                           This list is not exhaustive; if you're running
                           an older kernel you probably don't have fancy
                           I2O hardware anyway... */
                        switch (major) {
                        case 3:
                        case 21:
                        case 22:
                        case 33:
                        case 34:
                        case 36:
                        case 56:
                        case 57:
                        case 88:
                        case 89:
                        case 90:
                        case 91:
                                minor *= 64;
                                break;
                        case 9:
                        case 43:
                                break;
                        default:
                                minor *= 16;
                                break;
                        }
                        for (i = 0; i < n; i++) {
                                if (major == parts[i].major
                                        && minor == parts[i].minor)
                                        break;
                        }
                        if (i == n) continue;

                        /* We read the number of blocks. Blocks are stored in
                           512 bytes */
                        diskio_stats[i].read_bytes = rsect * 512;
                        diskio_stats[i].write_bytes = wsect * 512;
                        diskio_stats[i].systime = now;
                }
        }

        num_diskio = n;
out:
        if (f != NULL) fclose(f);
#endif

#ifdef CYGWIN
        sg_set_error(SG_ERROR_UNSUPPORTED, "Cygwin");
        return NULL;
#endif

        *entries=num_diskio;

        return diskio_stats;
}

sg_disk_io_stats *sg_get_disk_io_stats_diff(int *entries){
        VECTOR_DECLARE_STATIC(diff, sg_disk_io_stats, 1,
                              diskio_stat_init, diskio_stat_destroy);
        sg_disk_io_stats *src = NULL, *dest;
        int i, j, diff_count, new_count;

        if (diskio_stats == NULL) {
                /* No previous stats, so we can't calculate a difference. */
                return sg_get_disk_io_stats(entries);
        }

        /* Resize the results array to match the previous stats. */
        diff_count = VECTOR_SIZE(diskio_stats);
        if (VECTOR_RESIZE(diff, diff_count) < 0) {
                return NULL;
        }

        /* Copy the previous stats into the result. */
        for (i = 0; i < diff_count; i++) {
                src = &diskio_stats[i];
                dest = &diff[i];

                if (sg_update_string(&dest->disk_name, src->disk_name) < 0) {
                        return NULL;
                }
                dest->read_bytes = src->read_bytes;
                dest->write_bytes = src->write_bytes;
                dest->systime = src->systime;
        }

        /* Get a new set of stats. */
        if (sg_get_disk_io_stats(&new_count) == NULL) {
                return NULL;
        }

        /* For each previous stat... */
        for (i = 0; i < diff_count; i++) {
                dest = &diff[i];

                /* ... find the corresponding new stat ... */
                for (j = 0; j < new_count; j++) {
                        /* Try the new stat in the same position first,
                           since that's most likely to be it. */
                        src = &diskio_stats[(i + j) % new_count];
                        if (strcmp(src->disk_name, dest->disk_name) == 0) {
                                break;
                        }
                }
                if (j == new_count) {
                        /* No match found. */
                        continue;
                }

                /* ... and subtract the previous stat from it to get the
                   difference. */
                dest->read_bytes = src->read_bytes - dest->read_bytes;
                dest->write_bytes = src->write_bytes - dest->write_bytes;
                dest->systime = src->systime - dest->systime;
        }

        *entries = diff_count;
        return diff;
}

int sg_disk_io_compare_name(const void *va, const void *vb) {
        const sg_disk_io_stats *a = (const sg_disk_io_stats *)va;
        const sg_disk_io_stats *b = (const sg_disk_io_stats *)vb;

        return strcmp(a->disk_name, b->disk_name);
}

Revision:	1.67
Committed:	Thu Apr 8 13:44:44 2004 UTC (20 years, 1 month ago) by ats
Content type:	text/plain
Branch:	MAIN
Changes since 1.66:	+22 -1 lines
Log Message:	Add comparison functions for names where that's likely to be useful. Make the network_iface_stats example show how to use bsearch to find an interface by name.