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procps/proc/diskstats.c
Jim Warner e524e48138 library: eliminate distorted history 1st time switches 
Upon reflection, at the point where the 'priming read'
was introduced, any possibility of history distortions
was also eliminated.  This was true because all of the
'old' (zeroed) data will have been replaced with 'new'
data whenever a user finally calls get, select & reap.

Thus, any DELTA values will automatically reflect that
interval between 'new' and subsequent retrieval calls.

[ diskstats didn't actually employ a 1st time switch ]
[ like the others so we have changed a comment only. ]
[ but that module will retain something similar used ]
[ inside node_update whenever a new node is created. ]

Reference(s):
. priming read added to slabinfo
commit 5d5a52a380
. priming read added to diskstats
commit ecd64f4445
. priming read added to meminfo, stat, vmstat
commit 1a2b62c779

Signed-off-by: Jim Warner <james.warner@comcast.net>
2017-01-05 06:48:38 +11:00

1054 lines
33 KiB
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/*
* diskstat - Disk statistics - part of procps
*
* Copyright (C) 2003 Fabian Frederick
* Copyright (C) 2003 Albert Cahalan
* Copyright (C) 2015 Craig Small <csmall@enc.com.au>
* Copyright (C) 2016 Jim Warner <james.warner@comcast.net>
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <proc/procps-private.h>
#include <proc/diskstats.h>
/* The following define will cause the 'node_add' function to maintain our |
nodes list in ascending alphabetical order which could be used to avoid |
a sort on name. Without it, we default to a 'pull-up' stack at slightly |
more effort than a simple 'push-down' list to duplicate prior behavior. | */
//#define ALPHABETIC_NODES
#define DISKSTATS_LINE_LEN 1024
#define DISKSTATS_NAME_LEN 34
#define DISKSTATS_FILE "/proc/diskstats"
#define SYSBLOCK_DIR "/sys/block"
#define STACKS_INCR 64 // amount reap stack allocations grow
#define STR_COMPARE strverscmp
struct dev_data {
unsigned long reads;
unsigned long reads_merged;
unsigned long read_sectors;
unsigned long read_time;
unsigned long writes;
unsigned long writes_merged;
unsigned long write_sectors;
unsigned long write_time;
unsigned long io_inprogress;
unsigned long io_time;
unsigned long io_wtime;
};
struct dev_node {
char name[DISKSTATS_NAME_LEN+1];
int type;
int major;
int minor;
time_t stamped;
struct dev_data new;
struct dev_data old;
struct dev_node *next;
};
struct stacks_extent {
int ext_numstacks;
struct stacks_extent *next;
struct diskstats_stack **stacks;
};
struct ext_support {
int numitems; // includes 'logical_end' delimiter
enum diskstats_item *items; // includes 'logical_end' delimiter
struct stacks_extent *extents; // anchor for these extents
int dirty_stacks;
};
struct fetch_support {
struct diskstats_stack **anchor; // fetch consolidated extents
int n_alloc; // number of above pointers allocated
int n_inuse; // number of above pointers occupied
int n_alloc_save; // last known reap.stacks allocation
struct diskstats_reap results; // count + stacks for return to caller
};
struct diskstats_info {
int refcount;
FILE *diskstats_fp;
time_t old_stamp; /* previous read seconds */
time_t new_stamp; /* current read seconds */
struct dev_node *nodes; /* dev nodes anchor */
struct ext_support select_ext; /* supports concurrent select/reap */
struct ext_support fetch_ext; /* supports concurrent select/reap */
struct fetch_support fetch; /* support for procps_diskstats_reap */
struct diskstats_result get_this; /* used by procps_diskstats_get */
};
// ___ Results 'Set' Support ||||||||||||||||||||||||||||||||||||||||||||||||||
#define setNAME(e) set_diskstats_ ## e
#define setDECL(e) static void setNAME(e) \
(struct diskstats_result *R, struct dev_node *N)
// regular assignment
#define DEV_set(e,t,x) setDECL(e) { R->result. t = N-> x; }
#define REG_set(e,t,x) setDECL(e) { R->result. t = N->new . x; }
// delta assignment
#define HST_set(e,t,x) setDECL(e) { R->result. t = ( N->new . x - N->old. x ); }
setDECL(noop) { (void)R; (void)N; }
setDECL(extra) { (void)R; (void)N; }
DEV_set(DISKSTATS_NAME, str, name)
DEV_set(DISKSTATS_TYPE, s_int, type)
DEV_set(DISKSTATS_MAJOR, s_int, major)
DEV_set(DISKSTATS_MINOR, s_int, minor)
REG_set(DISKSTATS_READS, ul_int, reads)
REG_set(DISKSTATS_READS_MERGED, ul_int, reads_merged)
REG_set(DISKSTATS_READ_SECTORS, ul_int, read_sectors)
REG_set(DISKSTATS_READ_TIME, ul_int, read_time)
REG_set(DISKSTATS_WRITES, ul_int, writes)
REG_set(DISKSTATS_WRITES_MERGED, ul_int, writes_merged)
REG_set(DISKSTATS_WRITE_SECTORS, ul_int, write_sectors)
REG_set(DISKSTATS_WRITE_TIME, ul_int, write_time)
REG_set(DISKSTATS_IO_TIME, ul_int, io_time)
REG_set(DISKSTATS_IO_WTIME, ul_int, io_wtime)
REG_set(DISKSTATS_IO_INPROGRESS, s_int, io_inprogress)
HST_set(DISKSTATS_DELTA_READS, s_int, reads)
HST_set(DISKSTATS_DELTA_READS_MERGED, s_int, reads_merged)
HST_set(DISKSTATS_DELTA_READ_SECTORS, s_int, read_sectors)
HST_set(DISKSTATS_DELTA_READ_TIME, s_int, read_time)
HST_set(DISKSTATS_DELTA_WRITES, s_int, writes)
HST_set(DISKSTATS_DELTA_WRITES_MERGED, s_int, writes_merged)
HST_set(DISKSTATS_DELTA_WRITE_SECTORS, s_int, write_sectors)
HST_set(DISKSTATS_DELTA_WRITE_TIME, s_int, write_time)
HST_set(DISKSTATS_DELTA_IO_TIME, s_int, io_time)
HST_set(DISKSTATS_DELTA_IO_WTIME, s_int, io_wtime)
#undef setDECL
#undef DEV_set
#undef REG_set
#undef HST_set
// ___ Sorting Support ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
struct sort_parms {
int offset;
enum diskstats_sort_order order;
};
#define srtNAME(t) sort_diskstats_ ## t
#define srtDECL(t) static int srtNAME(t) \
(const struct diskstats_stack **A, const struct diskstats_stack **B, struct sort_parms *P)
srtDECL(s_int) {
const struct diskstats_result *a = (*A)->head + P->offset; \
const struct diskstats_result *b = (*B)->head + P->offset; \
return P->order * (a->result.s_int - b->result.s_int);
}
srtDECL(ul_int) {
const struct diskstats_result *a = (*A)->head + P->offset; \
const struct diskstats_result *b = (*B)->head + P->offset; \
if ( a->result.ul_int > b->result.ul_int ) return P->order > 0 ? 1 : -1; \
if ( a->result.ul_int < b->result.ul_int ) return P->order > 0 ? -1 : 1; \
return 0;
}
srtDECL(str) {
const struct diskstats_result *a = (*A)->head + P->offset;
const struct diskstats_result *b = (*B)->head + P->offset;
return P->order * STR_COMPARE(a->result.str, b->result.str);
}
srtDECL(noop) { \
(void)A; (void)B; (void)P; \
return 0;
}
#undef srtDECL
// ___ Controlling Table ||||||||||||||||||||||||||||||||||||||||||||||||||||||
typedef void (*SET_t)(struct diskstats_result *, struct dev_node *);
#define RS(e) (SET_t)setNAME(e)
typedef int (*QSR_t)(const void *, const void *, void *);
#define QS(t) (QSR_t)srtNAME(t)
#define TS(t) STRINGIFY(t)
#define TS_noop ""
/*
* Need it be said?
* This table must be kept in the exact same order as
* those *enum diskstats_item* guys ! */
static struct {
SET_t setsfunc; // the actual result setting routine
QSR_t sortfunc; // sort cmp func for a specific type
char *type2str; // the result type as a string value
} Item_table[] = {
/* setsfunc sortfunc type2str
---------------------------------- ----------- ---------- */
{ RS(noop), QS(noop), TS_noop },
{ RS(extra), QS(ul_int), TS_noop },
{ RS(DISKSTATS_NAME), QS(str), TS(str) },
{ RS(DISKSTATS_TYPE), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_MAJOR), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_MINOR), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_READS), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_READS_MERGED), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_READ_SECTORS), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_READ_TIME), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_WRITES), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_WRITES_MERGED), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_WRITE_SECTORS), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_WRITE_TIME), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_IO_TIME), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_IO_WTIME), QS(ul_int), TS(ul_int) },
{ RS(DISKSTATS_IO_INPROGRESS), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_READS), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_READS_MERGED), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_READ_SECTORS), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_READ_TIME), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_WRITES), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_WRITES_MERGED), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_WRITE_SECTORS), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_WRITE_TIME), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_IO_TIME), QS(s_int), TS(s_int) },
{ RS(DISKSTATS_DELTA_IO_WTIME), QS(s_int), TS(s_int) },
// dummy entry corresponding to DISKSTATS_logical_end ...
{ NULL, NULL, NULL }
};
/* please note,
* this enum MUST be 1 greater than the highest value of any enum */
enum diskstats_item DISKSTATS_logical_end = DISKSTATS_DELTA_IO_WTIME + 1;
#undef setNAME
#undef srtNAME
#undef RS
#undef QS
// ___ Private Functions ||||||||||||||||||||||||||||||||||||||||||||||||||||||
// --- dev_node specific support ----------------------------------------------
static struct dev_node *node_add (
struct diskstats_info *info,
struct dev_node *this)
{
struct dev_node *prev, *walk;
#ifdef ALPHABETIC_NODES
if (!info->nodes
|| (STR_COMPARE(this->name, info->nodes->name) < 0)) {
this->next = info->nodes;
info->nodes = this;
return this;
}
prev = info->nodes;
walk = info->nodes->next;
while (walk) {
if (STR_COMPARE(this->name, walk->name) < 0)
break;
prev = walk;
walk = walk->next;
}
prev->next = this;
this->next = walk;
#else
if (!info->nodes)
info->nodes = this;
else {
walk = info->nodes;
do {
prev = walk;
walk = walk->next;
} while (walk);
prev->next = this;
}
#endif
return this;
} // end: node_add
static void node_classify (
struct dev_node *this)
{
DIR *dirp;
struct dirent *dent;
/* all disks start off as partitions. this function
checks /sys/block and changes a device found there
into a disk. if /sys/block cannot have the directory
read, all devices are then treated as disks. */
this->type = DISKSTATS_TYPE_PARTITION;
if (!(dirp = opendir(SYSBLOCK_DIR))) {
this->type = DISKSTATS_TYPE_DISK;
return;
}
while ((dent = readdir(dirp))) {
if (strcmp(this->name, dent->d_name) == 0) {
this->type = DISKSTATS_TYPE_DISK;
break;
}
}
closedir(dirp);
} // end: node_classify
static struct dev_node *node_cut (
struct diskstats_info *info,
struct dev_node *this)
{
struct dev_node *node = info->nodes;
if (this) {
if (this == node) {
info->nodes = node->next;
return this;
}
do {
if (this == node->next) {
node->next = node->next->next;
return this;
}
node = node->next;
} while (node);
}
return NULL;
} // end: node_cut
static struct dev_node *node_get (
struct diskstats_info *info,
const char *name)
{
struct dev_node *node = info->nodes;
while (node) {
if (strcmp(name, node->name) == 0)
break;
node = node->next;
}
if (node) {
/* if this disk or partition has somehow gotten stale, we'll lose
it and then pretend it was never actually found ...
[ we test against both stamps in case a 'read' was avoided ] */
if (node->stamped != info->old_stamp
&& (node->stamped != info->new_stamp)) {
free(node_cut(info, node));
node = NULL;
}
}
return node;
} // end: node_get
static int node_update (
struct diskstats_info *info,
struct dev_node *source)
{
struct dev_node *target = node_get(info, source->name);
if (!target) {
if (!(target = malloc(sizeof(struct dev_node))))
return -ENOMEM;
memcpy(target, source, sizeof(struct dev_node));
// let's not distort the deltas when a new node is created ...
memcpy(&target->old, &target->new, sizeof(struct dev_data));
node_classify(target);
node_add(info, target);
return 0;
}
// remember history from last time around ...
memcpy(&source->old, &target->new, sizeof(struct dev_data));
// preserve some stuff from the existing node struct ...
source->type = target->type;
source->next = target->next;
// finally 'update' the existing node struct ...
memcpy(target, source, sizeof(struct dev_node));
return 0;
} // end: node_update
// ___ Private Functions ||||||||||||||||||||||||||||||||||||||||||||||||||||||
// --- generalized support ----------------------------------------------------
static inline void diskstats_assign_results (
struct diskstats_stack *stack,
struct dev_node *node)
{
struct diskstats_result *this = stack->head;
for (;;) {
enum diskstats_item item = this->item;
if (item >= DISKSTATS_logical_end)
break;
Item_table[item].setsfunc(this, node);
++this;
}
return;
} // end: diskstats_assign_results
static inline void diskstats_cleanup_stack (
struct diskstats_result *this)
{
for (;;) {
if (this->item >= DISKSTATS_logical_end)
break;
if (this->item > DISKSTATS_noop)
this->result.ul_int = 0;
++this;
}
} // end: diskstats_cleanup_stack
static inline void diskstats_cleanup_stacks_all (
struct ext_support *this)
{
struct stacks_extent *ext = this->extents;
int i;
while (ext) {
for (i = 0; ext->stacks[i]; i++)
diskstats_cleanup_stack(ext->stacks[i]->head);
ext = ext->next;
};
this->dirty_stacks = 0;
} // end: diskstats_cleanup_stacks_all
static void diskstats_extents_free_all (
struct ext_support *this)
{
while (this->extents) {
struct stacks_extent *p = this->extents;
this->extents = this->extents->next;
free(p);
};
} // end: diskstats_extents_free_all
static inline struct diskstats_result *diskstats_itemize_stack (
struct diskstats_result *p,
int depth,
enum diskstats_item *items)
{
struct diskstats_result *p_sav = p;
int i;
for (i = 0; i < depth; i++) {
p->item = items[i];
p->result.ul_int = 0;
++p;
}
return p_sav;
} // end: diskstats_itemize_stack
static void diskstats_itemize_stacks_all (
struct ext_support *this)
{
struct stacks_extent *ext = this->extents;
while (ext) {
int i;
for (i = 0; ext->stacks[i]; i++)
diskstats_itemize_stack(ext->stacks[i]->head, this->numitems, this->items);
ext = ext->next;
};
this->dirty_stacks = 0;
} // end: diskstats_itemize_stacks_all
static inline int diskstats_items_check_failed (
struct ext_support *this,
enum diskstats_item *items,
int numitems)
{
int i;
/* if an enum is passed instead of an address of one or more enums, ol' gcc
* will silently convert it to an address (possibly NULL). only clang will
* offer any sort of warning like the following:
*
* warning: incompatible integer to pointer conversion passing 'int' to parameter of type 'enum diskstats_item *'
* my_stack = procps_diskstats_select(info, DISKSTATS_noop, num);
* ^~~~~~~~~~~~~~~~
*/
if (numitems < 1
|| (void *)items < (void *)(unsigned long)(2 * DISKSTATS_logical_end))
return -1;
for (i = 0; i < numitems; i++) {
// a diskstats_item is currently unsigned, but we'll protect our future
if (items[i] < 0)
return -1;
if (items[i] >= DISKSTATS_logical_end)
return -1;
}
return 0;
} // end: diskstats_items_check_failed
/*
* diskstats_read_failed:
*
* @info: info structure created at procps_diskstats_new
*
* Read the data out of /proc/diskstats putting the information
* into the supplied info structure
*
* Returns: 0 on success, negative on error
*/
static int diskstats_read_failed (
struct diskstats_info *info)
{
static const char *fmtstr = "%d %d %" STRINGIFY(DISKSTATS_NAME_LEN) \
"s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu";
char buf[DISKSTATS_LINE_LEN];
struct dev_node node;
int rc;
if (!info->diskstats_fp
&& (!(info->diskstats_fp = fopen(DISKSTATS_FILE, "r"))))
return -errno;
if (fseek(info->diskstats_fp, 0L, SEEK_SET) == -1)
return -errno;
info->old_stamp = info->new_stamp;
info->new_stamp = time(NULL);
while (fgets(buf, DISKSTATS_LINE_LEN, info->diskstats_fp)) {
// clear out the soon to be 'current'values
memset(&node, 0, sizeof(struct dev_node));
rc = sscanf(buf, fmtstr
, &node.major
, &node.minor
, &node.name[0]
, &node.new.reads
, &node.new.reads_merged
, &node.new.read_sectors
, &node.new.read_time
, &node.new.writes
, &node.new.writes_merged
, &node.new.write_sectors
, &node.new.write_time
, &node.new.io_inprogress
, &node.new.io_time
, &node.new.io_wtime);
if (rc != 14) {
if (errno != 0)
return -errno;
return -EIO;
}
node.stamped = info->new_stamp;
if ((rc = node_update(info, &node)))
return rc;
}
return 0;
} // end: diskstats_read_failed
/*
* diskstats_stacks_alloc():
*
* Allocate and initialize one or more stacks each of which is anchored in an
* associated context structure.
*
* All such stacks will have their result structures properly primed with
* 'items', while the result itself will be zeroed.
*
* Returns a stacks_extent struct anchoring the 'heads' of each new stack.
*/
static struct stacks_extent *diskstats_stacks_alloc (
struct ext_support *this,
int maxstacks)
{
struct stacks_extent *p_blob;
struct diskstats_stack **p_vect;
struct diskstats_stack *p_head;
size_t vect_size, head_size, list_size, blob_size;
void *v_head, *v_list;
int i;
if (this == NULL || this->items == NULL)
return NULL;
if (maxstacks < 1)
return NULL;
vect_size = sizeof(void *) * maxstacks; // size of the addr vectors |
vect_size += sizeof(void *); // plus NULL addr delimiter |
head_size = sizeof(struct diskstats_stack); // size of that head struct |
list_size = sizeof(struct diskstats_result) * this->numitems; // any single results stack |
blob_size = sizeof(struct stacks_extent); // the extent anchor itself |
blob_size += vect_size; // plus room for addr vects |
blob_size += head_size * maxstacks; // plus room for head thing |
blob_size += list_size * maxstacks; // plus room for our stacks |
/* note: all of our memory is allocated in one single blob, facilitating some later free(). |
as a minimum, it's important that all of those result structs themselves always be |
contiguous within every stack since they will be accessed via a relative position. | */
if (NULL == (p_blob = calloc(1, blob_size)))
return NULL;
p_blob->next = this->extents; // push this extent onto... |
this->extents = p_blob; // ...some existing extents |
p_vect = (void *)p_blob + sizeof(struct stacks_extent); // prime our vector pointer |
p_blob->stacks = p_vect; // set actual vectors start |
v_head = (void *)p_vect + vect_size; // prime head pointer start |
v_list = v_head + (head_size * maxstacks); // prime our stacks pointer |
for (i = 0; i < maxstacks; i++) {
p_head = (struct diskstats_stack *)v_head;
p_head->head = diskstats_itemize_stack((struct diskstats_result *)v_list, this->numitems, this->items);
p_blob->stacks[i] = p_head;
v_list += list_size;
v_head += head_size;
}
p_blob->ext_numstacks = maxstacks;
return p_blob;
} // end: diskstats_stacks_alloc
static int diskstats_stacks_fetch (
struct diskstats_info *info)
{
#define n_alloc info->fetch.n_alloc
#define n_inuse info->fetch.n_inuse
#define n_saved info->fetch.n_alloc_save
struct stacks_extent *ext;
struct dev_node *node;
// initialize stuff -----------------------------------
if (!info->fetch.anchor) {
if (!(info->fetch.anchor = calloc(sizeof(void *), STACKS_INCR)))
return -ENOMEM;
n_alloc = STACKS_INCR;
}
if (!info->fetch_ext.extents) {
if (!(ext = diskstats_stacks_alloc(&info->fetch_ext, n_alloc)))
return -ENOMEM;
memset(info->fetch.anchor, 0, sizeof(void *) * n_alloc);
memcpy(info->fetch.anchor, ext->stacks, sizeof(void *) * n_alloc);
diskstats_itemize_stacks_all(&info->fetch_ext);
}
diskstats_cleanup_stacks_all(&info->fetch_ext);
// iterate stuff --------------------------------------
n_inuse = 0;
node = info->nodes;
while (node) {
if (!(n_inuse < n_alloc)) {
n_alloc += STACKS_INCR;
if ((!(info->fetch.anchor = realloc(info->fetch.anchor, sizeof(void *) * n_alloc)))
|| (!(ext = diskstats_stacks_alloc(&info->fetch_ext, STACKS_INCR))))
return -1;
memcpy(info->fetch.anchor + n_inuse, ext->stacks, sizeof(void *) * STACKS_INCR);
}
diskstats_assign_results(info->fetch.anchor[n_inuse], node);
++n_inuse;
node = node->next;
}
// finalize stuff -------------------------------------
/* note: we go to this trouble of maintaining a duplicate of the consolidated |
extent stacks addresses represented as our 'anchor' since these ptrs |
are exposed to a user (um, not that we don't trust 'em or anything). |
plus, we can NULL delimit these ptrs which we couldn't do otherwise. | */
if (n_saved < n_inuse + 1) {
n_saved = n_inuse + 1;
if (!(info->fetch.results.stacks = realloc(info->fetch.results.stacks, sizeof(void *) * n_saved)))
return -ENOMEM;
}
memcpy(info->fetch.results.stacks, info->fetch.anchor, sizeof(void *) * n_inuse);
info->fetch.results.stacks[n_inuse] = NULL;
info->fetch.results.total = n_inuse;
return n_inuse;
#undef n_alloc
#undef n_inuse
#undef n_saved
} // end: diskstats_stacks_fetch
static int diskstats_stacks_reconfig_maybe (
struct ext_support *this,
enum diskstats_item *items,
int numitems)
{
if (diskstats_items_check_failed(this, items, numitems))
return -EINVAL;
/* is this the first time or have things changed since we were last called?
if so, gotta' redo all of our stacks stuff ... */
if (this->numitems != numitems + 1
|| memcmp(this->items, items, sizeof(enum diskstats_item) * numitems)) {
// allow for our DISKSTATS_logical_end
if (!(this->items = realloc(this->items, sizeof(enum diskstats_item) * (numitems + 1))))
return -ENOMEM;
memcpy(this->items, items, sizeof(enum diskstats_item) * numitems);
this->items[numitems] = DISKSTATS_logical_end;
this->numitems = numitems + 1;
if (this->extents)
diskstats_extents_free_all(this);
return 1;
}
return 0;
} // end: diskstats_stacks_reconfig_maybe
// ___ Public Functions |||||||||||||||||||||||||||||||||||||||||||||||||||||||
// --- standard required functions --------------------------------------------
/*
* procps_diskstats_new():
*
* @info: location of returned new structure
*
* Returns: < 0 on failure, 0 on success along with
* a pointer to a new context struct
*/
PROCPS_EXPORT int procps_diskstats_new (
struct diskstats_info **info)
{
struct diskstats_info *p;
int rc;
if (info == NULL)
return -EINVAL;
if (!(p = calloc(1, sizeof(struct diskstats_info))))
return -ENOMEM;
p->refcount = 1;
/* do a priming read here for the following potential benefits: |
1) ensure there will be no problems with subsequent access |
2) make delta results potentially useful, even if 1st time |
3) elimnate need for history distortions 1st time 'switch' | */
if ((rc = diskstats_read_failed(p))) {
procps_diskstats_unref(&p);
return rc;
}
*info = p;
return 0;
} // end: procps_diskstats_new
PROCPS_EXPORT int procps_diskstats_ref (
struct diskstats_info *info)
{
if (info == NULL)
return -EINVAL;
info->refcount++;
return info->refcount;
} // end: procps_diskstats_ref
PROCPS_EXPORT int procps_diskstats_unref (
struct diskstats_info **info)
{
struct dev_node *node;
if (info == NULL || *info == NULL)
return -EINVAL;
(*info)->refcount--;
if ((*info)->refcount < 1) {
if ((*info)->diskstats_fp) {
fclose((*info)->diskstats_fp);
(*info)->diskstats_fp = NULL;
}
node = (*info)->nodes;
while (node) {
struct dev_node *p = node;
node = p->next;
free(p);
}
if ((*info)->select_ext.extents)
diskstats_extents_free_all((&(*info)->select_ext));
if ((*info)->select_ext.items)
free((*info)->select_ext.items);
if ((*info)->fetch.anchor)
free((*info)->fetch.anchor);
if ((*info)->fetch.results.stacks)
free((*info)->fetch.results.stacks);
if ((*info)->fetch_ext.extents)
diskstats_extents_free_all(&(*info)->fetch_ext);
if ((*info)->fetch_ext.items)
free((*info)->fetch_ext.items);
free(*info);
*info = NULL;
return 0;
}
return (*info)->refcount;
} // end: procps_diskstats_unref
// --- variable interface functions -------------------------------------------
PROCPS_EXPORT struct diskstats_result *procps_diskstats_get (
struct diskstats_info *info,
const char *name,
enum diskstats_item item)
{
struct dev_node *node;
time_t cur_secs;
if (info == NULL)
return NULL;
if (item < 0 || item >= DISKSTATS_logical_end)
return NULL;
/* we will NOT read the diskstat file with every call - rather, we'll offer
a granularity of 1 second between reads ... */
cur_secs = time(NULL);
if (1 <= cur_secs - info->new_stamp) {
if (diskstats_read_failed(info))
return NULL;
}
info->get_this.item = item;
// with 'get', we must NOT honor the usual 'noop' guarantee
// if (item > DISKSTATS_noop)
info->get_this.result.ul_int = 0;
if (!(node = node_get(info, name)))
return NULL;
Item_table[item].setsfunc(&info->get_this, node);
return &info->get_this;
} // end: procps_diskstats_get
/* procps_diskstats_reap():
*
* Harvest all the requested disks information providing
* the result stacks along with the total number of harvested.
*
* Returns: pointer to a diskstats_reap struct on success, NULL on error.
*/
PROCPS_EXPORT struct diskstats_reap *procps_diskstats_reap (
struct diskstats_info *info,
enum diskstats_item *items,
int numitems)
{
if (info == NULL || items == NULL)
return NULL;
if (0 > diskstats_stacks_reconfig_maybe(&info->fetch_ext, items, numitems))
return NULL;
if (info->fetch_ext.dirty_stacks)
diskstats_cleanup_stacks_all(&info->fetch_ext);
if (diskstats_read_failed(info))
return NULL;
diskstats_stacks_fetch(info);
info->fetch_ext.dirty_stacks = 1;
return &info->fetch.results;
} // end: procps_diskstats_reap
/* procps_diskstats_select():
*
* Obtain all the requested disk/partition information then return
* it in a single library provided results stack.
*
* Returns: pointer to a diskstats_stack struct on success, NULL on error.
*/
PROCPS_EXPORT struct diskstats_stack *procps_diskstats_select (
struct diskstats_info *info,
const char *name,
enum diskstats_item *items,
int numitems)
{
struct dev_node *node;
if (info == NULL || items == NULL)
return NULL;
if (0 > diskstats_stacks_reconfig_maybe(&info->select_ext, items, numitems))
return NULL;
if (!info->select_ext.extents
&& (!diskstats_stacks_alloc(&info->select_ext, 1)))
return NULL;
if (info->select_ext.dirty_stacks)
diskstats_cleanup_stacks_all(&info->select_ext);
if (diskstats_read_failed(info))
return NULL;
if (!(node = node_get(info, name)))
return NULL;
diskstats_assign_results(info->select_ext.extents->stacks[0], node);
info->select_ext.dirty_stacks = 1;
return info->select_ext.extents->stacks[0];
} // end: procps_diskstats_select
/*
* procps_diskstats_sort():
*
* Sort stacks anchored in the passed stack pointers array
* based on the designated sort enumerator and specified order.
*
* Returns those same addresses sorted.
*
* Note: all of the stacks must be homogeneous (of equal length and content).
*/
PROCPS_EXPORT struct diskstats_stack **procps_diskstats_sort (
struct diskstats_info *info,
struct diskstats_stack *stacks[],
int numstacked,
enum diskstats_item sortitem,
enum diskstats_sort_order order)
{
struct diskstats_result *p;
struct sort_parms parms;
int offset;
if (info == NULL || stacks == NULL)
return NULL;
// a diskstats_item is currently unsigned, but we'll protect our future
if (sortitem < 0 || sortitem >= DISKSTATS_logical_end)
return NULL;
if (order != DISKSTATS_SORT_ASCEND && order != DISKSTATS_SORT_DESCEND)
return NULL;
if (numstacked < 2)
return stacks;
offset = 0;
p = stacks[0]->head;
for (;;) {
if (p->item == sortitem)
break;
++offset;
if (p->item >= DISKSTATS_logical_end)
return NULL;
++p;
}
parms.offset = offset;
parms.order = order;
qsort_r(stacks, numstacked, sizeof(void *), (QSR_t)Item_table[p->item].sortfunc, &parms);
return stacks;
} // end: procps_diskstats_sort
// --- special debugging function(s) ------------------------------------------
/*
* The following isn't part of the normal programming interface. Rather,
* it exists to validate result types referenced in application programs.
*
* It's used only when:
* 1) the 'XTRA_PROCPS_DEBUG' has been defined, or
* 2) the '#include <proc/xtra-procps-debug.h>' used
*/
PROCPS_EXPORT struct diskstats_result *xtra_diskstats_get (
struct diskstats_info *info,
const char *name,
enum diskstats_item actual_enum,
const char *typestr,
const char *file,
int lineno)
{
struct diskstats_result *r = procps_diskstats_get(info, name, actual_enum);
if (actual_enum < 0 || actual_enum >= DISKSTATS_logical_end) {
fprintf(stderr, "%s line %d: invalid item = %d, type = %s\n"
, file, lineno, actual_enum, typestr);
}
if (r) {
char *str = Item_table[r->item].type2str;
if (str[0]
&& (strcmp(typestr, str)))
fprintf(stderr, "%s line %d: was %s, expected %s\n", file, lineno, typestr, str);
}
return r;
} // end: xtra_diskstats_get_
PROCPS_EXPORT struct diskstats_result *xtra_diskstats_val (
int relative_enum,
const char *typestr,
const struct diskstats_stack *stack,
struct diskstats_info *info,
const char *file,
int lineno)
{
char *str;
int i;
for (i = 0; stack->head[i].item < DISKSTATS_logical_end; i++)
;
if (relative_enum < 0 || relative_enum >= i) {
fprintf(stderr, "%s line %d: invalid relative_enum = %d, type = %s\n"
, file, lineno, relative_enum, typestr);
return NULL;
}
str = Item_table[stack->head[relative_enum].item].type2str;
if (str[0]
&& (strcmp(typestr, str))) {
fprintf(stderr, "%s line %d: was %s, expected %s\n", file, lineno, typestr, str);
}
return &stack->head[relative_enum];
} // end: xtra_diskstats_val
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