libzutil: allow to display powers of 1000 bytes

ZFS displays bytes with K/M/G/T/P/E prefixes. They represent powers of
1024 bytes, i.e. KiB, MiB, GiB, TiB, PiB, EiB.
Some users may want these prefixes to represent powers of 1000 bytes,
i.e. KB, MB, GB, TB, PB, EB.
This adds the new unit format and allows to use such display by
defining an environment variable.

Signed-off-by: Julien Cassette <[email protected]>

include/libzutil.h

@@ -144,13 +144,15 @@ _LIBZUTIL_H boolean_t zfs_isnumber(const char *);
  * ZFS_NICENUM_TIME:	Print nanosecs, microsecs, millisecs, seconds...
  * ZFS_NICENUM_RAW:	Print the raw number without any formatting
  * ZFS_NICENUM_RAWTIME:	Same as RAW, but print dashes ('-') for zero.
+ * ZFS_NICENUM_1000: Same as ZFS_NICENUM_BYTES but use powers of 1000.
  */
 enum zfs_nicenum_format {
 	ZFS_NICENUM_1024 = 0,
 	ZFS_NICENUM_BYTES = 1,
 	ZFS_NICENUM_TIME = 2,
 	ZFS_NICENUM_RAW = 3,
-	ZFS_NICENUM_RAWTIME = 4
+	ZFS_NICENUM_RAWTIME = 4,
+	ZFS_NICENUM_1000 = 5
 };
 
 /*

lib/libzutil/zutil_nicenum.c

@@ -26,6 +26,7 @@
 #include <ctype.h>
 #include <math.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <libzutil.h>
 #include <string.h>
 
@@ -64,19 +65,22 @@ zfs_nicenum_format(uint64_t num, char *buf, size_t buflen,
 	uint64_t n = num;
 	int index = 0;
 	const char *u;
-	const char *units[3][7] = {
+	const char *units[6][7] = {
 	    [ZFS_NICENUM_1024] = {"", "K", "M", "G", "T", "P", "E"},
 	    [ZFS_NICENUM_BYTES] = {"B", "K", "M", "G", "T", "P", "E"},
-	    [ZFS_NICENUM_TIME] = {"ns", "us", "ms", "s", "?", "?", "?"}
+	    [ZFS_NICENUM_TIME] = {"ns", "us", "ms", "s", "?", "?", "?"},
+	    [ZFS_NICENUM_1000] = {"B", "K", "M", "G", "T", "P", "E"}
 	};
 
 	const int units_len[] = {[ZFS_NICENUM_1024] = 6,
 	    [ZFS_NICENUM_BYTES] = 6,
-	    [ZFS_NICENUM_TIME] = 4};
+	    [ZFS_NICENUM_TIME] = 4,
+	    [ZFS_NICENUM_1000] = 6};
 
 	const int k_unit[] = {	[ZFS_NICENUM_1024] = 1024,
 	    [ZFS_NICENUM_BYTES] = 1024,
-	    [ZFS_NICENUM_TIME] = 1000};
+	    [ZFS_NICENUM_TIME] = 1000,
+	    [ZFS_NICENUM_1000] = 1000};
 
 	double val;
 
@@ -180,5 +184,9 @@ zfs_niceraw(uint64_t num, char *buf, size_t buflen)
 void
 zfs_nicebytes(uint64_t num, char *buf, size_t buflen)
 {
-	zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_BYTES);
+	if (getenv("ZFS_OUTPUT_BYTES_SI") != NULL) {
+		zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_1000);
+	} else {
+		zfs_nicenum_format(num, buf, buflen, ZFS_NICENUM_BYTES);
+	}
 }

man/man8/zdb.8

@@ -567,6 +567,15 @@ refcnt   blocks   LSIZE   PSIZE   DSIZE   blocks   LSIZE   PSIZE   DSIZE
 dedup = 1.11, compress = 1.80, copies = 1.00, dedup * compress / copies = 2.00
 .Ed
 .
+.Sh ENVIRONMENT VARIABLES
+.Bl -tag -width "ZFS_OUTPUT_BYTES_SI"
+.\" Shared with zfs.8 and zpool.8
+.It Sy ZFS_OUTPUT_BYTES_SI
+Make K/M/G/T/P/E prefixes in
+.Nm zdb
+output to represent powers of 1000 bytes, i.e. KB, MB, GB, TB, PB, EB.
+.El
+.
 .Sh SEE ALSO
 .Xr zfs 8 ,
 .Xr zpool 8

man/man8/zfs.8

@@ -763,6 +763,12 @@ to set the maximum pipe size for sends/recieves.
 Disabled by default on Linux
 due to an unfixed deadlock in Linux's pipe size handling code.
 .
+.\" Shared with zdb.8 and zpool.8
+.It Sy ZFS_OUTPUT_BYTES_SI
+Make K/M/G/T/P/E prefixes in
+.Nm zfs
+output to represent powers of 1000 bytes, i.e. KB, MB, GB, TB, PB, EB.
+.
 .\" Shared with zpool.8
 .It Sy ZFS_MODULE_TIMEOUT
 Time, in seconds, to wait for

man/man8/zpool.8

@@ -561,6 +561,12 @@ If
 .Sy ZPOOL_SCRIPTS_ENABLED
 is not set, it is assumed that the user is allowed to run
 .Nm zpool Cm status Ns / Ns Cm iostat Fl c .
+.\" Shared with zdb.8 and zfs.8
+.It Sy ZFS_OUTPUT_BYTES_SI
+Make K/M/G/T/P/E prefixes in
+.Nm zpool
+output to represent powers of 1000 bytes, i.e. KB, MB, GB, TB, PB, EB.
+.
 .\" Shared with zfs.8
 .It Sy ZFS_MODULE_TIMEOUT
 Time, in seconds, to wait for