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v4.0.6
library/diskstats.c
1 035 строк
33 KB
Jim Warner
library: other changes for 'stable' mergesort function
22 ноя 2025, 01:13
22 ноя 2025, 01:13
5d3edd4
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/* * diskstats.c - disk I/O related definitions for libproc2 * * Copyright © 2015-2025 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 <sort.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(STACKS_INCR, sizeof(void *)))) 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; if (!mergesort_r(stacks, numstacked, (QSR_t)Item_table[p->item].sortfunc, &parms)) return NULL; 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