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bin/uuidgen: add support for v4 uuids

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The version 4 UUID is meant for generating UUIDs from truly-random or
pseudo-random numbers. [1]

bin/uuidgen gained the new flag '-r' to create version 4 UUID.

[1] RFC 4122, https://www.rfc-editor.org/rfc/rfc4122#section-4.4

Reviewed by:		pstef
Approved by:		bapt
MFC after:		1 week
Differential Revision:	https://reviews.freebsd.org/D37695
This commit is contained in:
Tobias C. Berner 2022-12-14 06:59:36 +01:00
parent 195f1b124d
commit f176fe8e7f
2 changed files with 67 additions and 12 deletions
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3
bin/uuidgen/uuidgen.1
View File

@ -33,6 +33,7 @@
.Sh SYNOPSIS
.Nm
.Op Fl 1
.Op Fl r
.Op Fl n Ar count
.Op Fl o Ar filename
.Sh DESCRIPTION
@ -50,6 +51,8 @@ This option only has effect if multiple identifiers are to be generated and
instructs
.Nm
to not generate them in batch, but one at a time.
.It Fl r
This option controls creation of random UUID (version 4).
.It Fl n
This option controls the number of identifiers generated.
By default, multiple identifiers are generated in batch.

76
bin/uuidgen/uuidgen.c
View File

@ -1,5 +1,6 @@
/*
* Copyright (c) 2002 Marcel Moolenaar
* Copyright (c) 2022 Tobias C. Berner
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -40,26 +41,63 @@ __FBSDID("$FreeBSD$");
static void
usage(void)
{
(void)fprintf(stderr, "usage: uuidgen [-1] [-n count] [-o filename]\n");
(void)fprintf(stderr,
"usage: uuidgen [-1] [-r] [-n count] [-o filename]\n");
exit(1);
}
static int
uuidgen_v4(struct uuid *store, int count)
{
int size;
struct uuid *item;
if (count < 1) {
errno = EINVAL;
return (-1);
}
size = sizeof(struct uuid) * count;
arc4random_buf(store, size);
item = store;
for (int i = 0; i < count; ++i) {
/*
* Set the two most significant bits (bits 6 and 7) of the
* clock_seq_hi_and_reserved to zero and one, respectively.
*/
item->clock_seq_hi_and_reserved &= ~(3 << 6);
item->clock_seq_hi_and_reserved |= (2 << 6);
/*
* Set the four most significant bits (bits 12 through 15) of
* the time_hi_and_version field to the 4-bit version number
* from Section 4.1.3.
*/
item->time_hi_and_version &= ~(15 << 12);
item->time_hi_and_version |= (4 << 12);
item++;
};
return (0);
}
int
main(int argc, char *argv[])
{
FILE *fp;
uuid_t *store, *uuid;
char *p;
int ch, count, i, iterate, status;
int ch, count, i, iterate, status, version;
count = -1; /* no count yet */
fp = stdout; /* default output file */
iterate = 0; /* not one at a time */
while ((ch = getopt(argc, argv, "1n:o:")) != -1)
count = -1; /* no count yet */
fp = stdout; /* default output file */
iterate = 0; /* not one at a time */
version = 1; /* create uuid v1 by default */
while ((ch = getopt(argc, argv, "1rn:o:")) != -1)
switch (ch) {
case '1':
iterate = 1;
break;
case 'r':
version = 4;
break;
case 'n':
if (count > 0)
usage();
@ -92,19 +130,33 @@ main(int argc, char *argv[])
if (count == -1)
count = 1;
store = (uuid_t*)malloc(sizeof(uuid_t) * count);
store = (uuid_t *)malloc(sizeof(uuid_t) * count);
if (store == NULL)
err(1, "malloc()");
if (!iterate) {
/* Get them all in a single batch */
if (uuidgen(store, count) != 0)
err(1, "uuidgen()");
if (version == 1) {
if (uuidgen(store, count) != 0)
err(1, "uuidgen()");
} else if (version == 4) {
if (uuidgen_v4(store, count) != 0)
err(1, "uuidgen_v4()");
} else {
err(1, "unsupported version");
}
} else {
uuid = store;
for (i = 0; i < count; i++) {
if (uuidgen(uuid++, 1) != 0)
err(1, "uuidgen()");
if (version == 1) {
if (uuidgen(uuid++, 1) != 0)
err(1, "uuidgen()");
} else if (version == 4) {
if (uuidgen_v4(uuid++, 1) != 0)
err(1, "uuidgen_v4()");
} else {
err(1, "unsupported version");
}
}
}
@ -112,7 +164,7 @@ main(int argc, char *argv[])
while (count--) {
uuid_to_string(uuid++, &p, &status);
if (status != uuid_s_ok)
err(1, "cannot stringify a UUID");
err(1, "cannot stringify a UUID");
fprintf(fp, "%s\n", p);
free(p);
}