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// copyright 2012–2021 nick black
#ifndef GROWLIGHT_STATS
#define GROWLIGHT_STATS
#ifdef __cplusplus
extern "C" {
#endif
#include <limits.h>
#include <stdint.h>
// See Linux's documentation/iostats.txt for description of the procfs disk
// statistics. On Linux 4.18+, we have 17 fields:
//
// major minor devname
// readsComp readsMerged sectorsRead msRead
// writesComp writesMerged sectorsWritten msWritten
// iosInProgress msIOs weightedmsIOs
// discardsComp discardsMerged sectorsDiscarded msDiscarded
//
// Prior to 4.18, the last four fields were not present.
typedef struct statpack {
uint64_t sectors_read;
uint64_t sectors_written;
} statpack;
typedef struct diskstats {
char name[NAME_MAX + 1];
statpack total;
} diskstats;
// Reads the entirety of /proc/diskstats, and copies the results we care about
// into a heap-allocated array of stats objects. We use /proc/diskstats because
// we'd otherwise need open a sysfs file per partition/block device. The return
// value is the number of entries in *stats. *stats is NULL iff the return
// value is less than or equal to 0. An error results in a negative return.
int read_proc_diskstats(diskstats **stats);
// Allows the path to be specified.
int read_diskstats(const char *path, diskstats **stats);
#ifdef __cplusplus
}
#endif
#endif
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