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procps/library/diskstats.c
Jim Warner 3c3a9354a3 library: correct boo-boos in /proc file opening commit 
Signed-off-by: Jim Warner <james.warner@comcast.net>
2024-06-30 19:34:02 +10:00

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/*
* diskstats.c - disk I/O related definitions for libproc2
*
* Copyright © 2015-2024 Jim Warner <james.warner@comcast.net>
* Copyright © 2015-2023 Craig Small <csmall@dropbear.xyz>
* Copyright © 2003 Albert Cahalan
* Copyright © 2003 Fabian Frederick
*
* 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 "procps-private.h"
#include "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
/* ----------------------------------------------------------------------- +
this provision can help ensure that our Item_table remains synchronized |
with the enumerators found in the associated header file. It's intended |
to only be used locally (& temporarily) at some point before a release! | */
// #define ITEMTABLE_DEBUG //--------------------------------------------- |
// ----------------------------------------------------------------------- +
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
};
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_reaped 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)N; R->result.ul_int = 0; }
DEV_set(NAME, str, name)
DEV_set(TYPE, s_int, type)
DEV_set(MAJOR, s_int, major)
DEV_set(MINOR, s_int, minor)
REG_set(READS, ul_int, reads)
REG_set(READS_MERGED, ul_int, reads_merged)
REG_set(READ_SECTORS, ul_int, read_sectors)
REG_set(READ_TIME, ul_int, read_time)
REG_set(WRITES, ul_int, writes)
REG_set(WRITES_MERGED, ul_int, writes_merged)
REG_set(WRITE_SECTORS, ul_int, write_sectors)
REG_set(WRITE_TIME, ul_int, write_time)
REG_set(IO_TIME, ul_int, io_time)
REG_set(WEIGHTED_TIME, ul_int, io_wtime)
REG_set(IO_INPROGRESS, s_int, io_inprogress)
HST_set(DELTA_READS, s_int, reads)
HST_set(DELTA_READS_MERGED, s_int, reads_merged)
HST_set(DELTA_READ_SECTORS, s_int, read_sectors)
HST_set(DELTA_READ_TIME, s_int, read_time)
HST_set(DELTA_WRITES, s_int, writes)
HST_set(DELTA_WRITES_MERGED, s_int, writes_merged)
HST_set(DELTA_WRITE_SECTORS, s_int, write_sectors)
HST_set(DELTA_WRITE_TIME, s_int, write_time)
HST_set(DELTA_IO_TIME, s_int, io_time)
HST_set(DELTA_WEIGHTED_TIME, 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 *);
#ifdef ITEMTABLE_DEBUG
#define RS(e) (SET_t)setNAME(e), DISKSTATS_ ## e, STRINGIFY(DISKSTATS_ ## e)
#else
#define RS(e) (SET_t)setNAME(e)
#endif
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
#ifdef ITEMTABLE_DEBUG
int enumnumb; // enumerator (must match position!)
char *enum2str; // enumerator name as a char* string
#endif
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(NAME), QS(str), TS(str) },
{ RS(TYPE), QS(s_int), TS(s_int) },
{ RS(MAJOR), QS(s_int), TS(s_int) },
{ RS(MINOR), QS(s_int), TS(s_int) },
{ RS(READS), QS(ul_int), TS(ul_int) },
{ RS(READS_MERGED), QS(ul_int), TS(ul_int) },
{ RS(READ_SECTORS), QS(ul_int), TS(ul_int) },
{ RS(READ_TIME), QS(ul_int), TS(ul_int) },
{ RS(WRITES), QS(ul_int), TS(ul_int) },
{ RS(WRITES_MERGED), QS(ul_int), TS(ul_int) },
{ RS(WRITE_SECTORS), QS(ul_int), TS(ul_int) },
{ RS(WRITE_TIME), QS(ul_int), TS(ul_int) },
{ RS(IO_TIME), QS(ul_int), TS(ul_int) },
{ RS(WEIGHTED_TIME), QS(ul_int), TS(ul_int) },
{ RS(IO_INPROGRESS), QS(s_int), TS(s_int) },
{ RS(DELTA_READS), QS(s_int), TS(s_int) },
{ RS(DELTA_READS_MERGED), QS(s_int), TS(s_int) },
{ RS(DELTA_READ_SECTORS), QS(s_int), TS(s_int) },
{ RS(DELTA_READ_TIME), QS(s_int), TS(s_int) },
{ RS(DELTA_WRITES), QS(s_int), TS(s_int) },
{ RS(DELTA_WRITES_MERGED), QS(s_int), TS(s_int) },
{ RS(DELTA_WRITE_SECTORS), QS(s_int), TS(s_int) },
{ RS(DELTA_WRITE_TIME), QS(s_int), TS(s_int) },
{ RS(DELTA_IO_TIME), QS(s_int), TS(s_int) },
{ RS(DELTA_WEIGHTED_TIME), QS(s_int), TS(s_int) },
};
/* please note,
* this enum MUST be 1 greater than the highest value of any enum */
enum diskstats_item DISKSTATS_logical_end = MAXTABLE(Item_table);
#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 0;
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 1;
}
// 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 1;
} // 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 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;
}
return p_sav;
} // end: diskstats_itemize_stack
static inline int diskstats_items_check_failed (
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, 1 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 1;
else {
if (-1 == fseek(info->diskstats_fp, 0L, SEEK_SET)) {
/* a concession to libvirt lxc support, which has been
known to treat a /proc file as non-seekable ... */
if (ESPIPE != errno)
return 1;
fclose(info->diskstats_fp);
if (!(info->diskstats_fp = fopen(DISKSTATS_FILE, "r")))
return 1;
}
}
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) {
errno = ERANGE;
return 1;
}
node.stamped = info->new_stamp;
if (!node_update(info, &node))
return 1; // here, errno was set to ENOMEM
}
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;
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 -1; // here, errno was set to ENOMEM
memcpy(info->fetch.anchor, ext->stacks, sizeof(void *) * n_alloc);
}
// 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; // here, errno was set to ENOMEM
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 -1;
}
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(items, numitems))
return -1;
/* 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 -1; // here, errno was set to ENOMEM
memcpy(this->items, items, sizeof(enum diskstats_item) * numitems);
this->items[numitems] = DISKSTATS_logical_end;
this->numitems = numitems + 1;
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;
#ifdef ITEMTABLE_DEBUG
int i, failed = 0;
for (i = 0; i < MAXTABLE(Item_table); i++) {
if (i != Item_table[i].enumnumb) {
fprintf(stderr, "%s: enum/table error: Item_table[%d] was %s, but its value is %d\n"
, __FILE__, i, Item_table[i].enum2str, Item_table[i].enumnumb);
failed = 1;
}
}
if (failed) _Exit(EXIT_FAILURE);
#endif
if (info == NULL || *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 (diskstats_read_failed(p)) {
procps_diskstats_unref(&p);
return -errno;
}
*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) {
int errno_sav = errno;
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;
errno = errno_sav;
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;
errno = EINVAL;
if (info == NULL)
return NULL;
if (item < 0 || item >= DISKSTATS_logical_end)
return NULL;
errno = 0;
/* 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
info->get_this.result.ul_int = 0;
if (!(node = node_get(info, name))) {
errno = ENXIO;
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_reaped struct on success, NULL on error.
*/
PROCPS_EXPORT struct diskstats_reaped *procps_diskstats_reap (
struct diskstats_info *info,
enum diskstats_item *items,
int numitems)
{
errno = EINVAL;
if (info == NULL || items == NULL)
return NULL;
if (0 > diskstats_stacks_reconfig_maybe(&info->fetch_ext, items, numitems))
return NULL; // here, errno may be overridden with ENOMEM
errno = 0;
if (diskstats_read_failed(info))
return NULL;
if (0 > diskstats_stacks_fetch(info))
return NULL;
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;
errno = EINVAL;
if (info == NULL || items == NULL)
return NULL;
if (0 > diskstats_stacks_reconfig_maybe(&info->select_ext, items, numitems))
return NULL; // here, errno may be overridden with ENOMEM
errno = 0;
if (!info->select_ext.extents
&& (!diskstats_stacks_alloc(&info->select_ext, 1)))
return NULL;
if (diskstats_read_failed(info))
return NULL;
if (!(node = node_get(info, name))) {
errno = ENXIO;
return NULL;
}
diskstats_assign_results(info->select_ext.extents->stacks[0], node);
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;
errno = EINVAL;
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;
}
errno = 0;
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) an #include of 'xtra-procps-debug.h' is 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,
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, valid range = 0-%d\n"
, file, lineno, relative_enum, i-1);
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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