search for: random_state

v2: - Fix seeding. - Add a test that nbdkit-random-plugin is producing something which looks at least somewhat random. Rich.

...t http://xoshiro.di.unimi.it/ . Specifically + * this is ‘xoshiro256** 1.0’. + * + * This does _NOT_ generate cryptographically secure random numbers + * (CSPRNG) and so should not be used when cryptography or security is + * required - use gcrypt if you need those. + */ + +/* You can seed ‘struct random_state’ by setting the s[] elements + * directly - but not you must NOT set it all to zero. OR if you have + * a 64 bit seed, you can use xsrandom below to initialize the state. + */ +struct random_state { + uint64_t s[4]; +}; + +static inline uint64_t +snext (uint64_t *seed) +{ + uint64_t z = (*seed +...

...ebastiano Vigna at http://xoshiro.di.unimi.it/ . Specifically + * this is ‘xoshiro256** 1.0’. + * + * This does _NOT_ generate cryptographically secure random numbers + * (CSPRNG) and so should not be used when cryptography or security is + * required - use gcrypt if you need those. + */ + +struct random_state { + uint64_t s[4]; +}; + +static inline uint64_t +rotl (const uint64_t x, int k) +{ + return (x << k) | (x >> (64 - k)); +} + +/* Returns 64 random bits. Updates the state. */ +uint64_t +xrandom (struct random_state *state) +{ + const uint64_t result_starstar = rotl (state->s[1]...

...cally > + * this is ‘xoshiro256** 1.0’. > + * > + * This does _NOT_ generate cryptographically secure random numbers > + * (CSPRNG) and so should not be used when cryptography or security is > + * required - use gcrypt if you need those. > + */ > + > +/* You can seed ‘struct random_state’ by setting the s[] elements > + * directly - but not you must NOT set it all to zero. OR if you have s/not you/note you/ > + * a 64 bit seed, you can use xsrandom below to initialize the state. > + */ > +struct random_state { > + uint64_t s[4]; > +}; > + > +static inlin...

...struct file *files = NULL; size_t nr_files = 0; /* Virtual disk layout. */ -struct regions regions; +regions the_regions; /* Primary and secondary partition tables and extended boot records. * Secondary PT is only used for GPT. EBR array of sectors is only @@ -93,7 +93,7 @@ static struct random_state random_state; static void partitioning_load (void) { - init_regions (&regions); + init_regions (&the_regions); parse_guid (DEFAULT_TYPE_GUID, type_guid); xsrandom (time (NULL), &random_state); } @@ -110,7 +110,7 @@ partitioning_unload (void) /* We don't need to free r...

.../filters/error/error.c @@ -283,9 +283,10 @@ random_error (const struct error_settings *error_settings, * representable in a 64 bit integer, and because we don't need all * this precision anyway, let's work in 32 bits. */ - pthread_mutex_lock (&lock); - rand = xrandom (&random_state) & UINT32_MAX; - pthread_mutex_unlock (&lock); + { + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); + rand = xrandom (&random_state) & UINT32_MAX; + } if (rand >= error_settings->rate * UINT32_MAX) return false; diff --git a/filters/log/log.c b/filters/log/log.c...

...: disk[%zu] != expected type %" PRIu32 "\n", + j, type); + dump_extents_map (map); + exit (EXIT_FAILURE); + } + } + + return 0; +} + +int +main (int argc, char *argv[]) +{ + unsigned i; + uint64_t offset, length; + uint32_t type; + size_t j; + struct random_state random_state; + struct nbdkit_extents_map *map; + + xsrandom (time (NULL), &random_state); + + map = nbdkit_extents_new (); + assert (map != NULL); + + for (i = 0; i < 1000; ++i) { + type = xrandom (&random_state); + type &= 3; + offset = xrandom (&random_state); +...

...ory, label, type, size parameters. */ +char *dir; +const char *label; +const char *type = "ext2"; +int64_t size; +bool size_add_estimate; /* if size=+SIZE was used */ + +/* Virtual disk. */ +static struct virtual_disk disk; + +/* Used to create a random GUID for the partition. */ +struct random_state random_state; + +static void +linuxdisk_load (void) +{ + init_virtual_disk (&disk); + xsrandom (time (NULL), &random_state); +} + +static void +linuxdisk_unload (void) +{ + free_virtual_disk (&disk); + free (dir); +} + +static int +linuxdisk_config (const char *key, const char *valu...

Should we use attribute((nonnull)) at all? There's a very interesting history of this in libvirt -- try looking at commit eefb881 plus the commits referencing eefb881 -- but it does seem to work for me using recent GCC and Clang. I only did a few functions because annotating them gets old quickly... Rich.

...rds. + * Secondary PT is only used for GPT. EBR array of sectors is only + * used for MBR with > 4 partitions and has length equal to nr_files-3. + */ +unsigned char *primary = NULL, *secondary = NULL, **ebr = NULL; /* Used to generate random unique partition GUIDs for GPT. */ static struct random_state random_state; @@ -106,12 +109,17 @@ partitioning_unload (void) free (files); /* We don't need to free regions.regions[].u.data because it points - * to either primary or secondary which we free here. + * to primary, secondary or ebr which we free here. */ free_regions (&r...

An evolution of the patch I posted yesterday to qemu-devel (https://www.mail-archive.com/qemu-devel@nongnu.org/msg588920.html) which (a) works and (b) has a test. Rich.

...disk.h" + +/* Directory, label, size parameters. */ +char **dirs; +size_t nr_dirs; +const char *label; +int64_t size; +bool size_add_estimate; /* if size=+SIZE was used */ + +/* Virtual disk. */ +static struct virtual_disk disk; + +/* Used to create a random GUID for the partition. */ +struct random_state random_state; + +static void +linuxdisk_load (void) +{ + load_filesystem (); + init_virtual_disk (&disk); + xsrandom (time (NULL), &random_state); +} + +static void +linuxdisk_unload (void) +{ + size_t i; + + free_virtual_disk (&disk); + + for (i = 0; i < nr_dirs; ++i) + fre...

I do have a question about whether patch 2 is right, or whether I've exposed a bigger problem in the truncate (and possibly other) filter, but the rest seem fairly straightforward. Eric Blake (4): server: Check for pthread lock failures truncate: Factor out reading real_size under mutex plugins: Check for mutex failures filters: Check for mutex failures filters/cache/cache.c

...andom.h index eb08295..098c6d6 100644 --- a/common/include/random.h +++ b/common/include/random.h @@ -67,7 +67,7 @@ snext (uint64_t *seed) } /* Seed the random state from a 64 bit seed. */ -static inline void +static inline void __attribute__((__nonnull__ (2))) xsrandom (uint64_t seed, struct random_state *state) { state->s[0] = snext (&seed); @@ -83,7 +83,7 @@ rotl (const uint64_t x, int k) } /* Returns 64 random bits. Updates the state. */ -static inline uint64_t +static inline uint64_t __attribute__((__nonnull__ (1))) xrandom (struct random_state *state) { const uint64_t resu...

For v3 I reimplemented this using mke2fs -d. This obviously makes the implementation a whole lot simpler, but cannot support multiple directory merging. Patches 1-3 are the same as before. I've also reproduced the notes from v2 below. v2: - Fix inconsistent tab/space. - All 3 plugins now contain a block of text pointing to the other 2 plugins. - TMDIR -> TMPDIR - Unlink the

v1 was here: https://www.redhat.com/archives/libguestfs/2019-January/msg00008.html In v2 I have provided two patches: The first patch extends attribute((nonnull)) to most internal functions, but not to the external API. The second patch uses a macro so that attribute((format)) is only used in the public API on GCC or Clang. At least in theory these headers could be used by a C compiler which

I want to post this but mainly for discussion and early review. It's not safe for these patches to all go upstream yet (because not all filters have been checked/adjusted), but if any patches were to go upstream then probably 1 & 2 only are safe. File, VDDK, memory and data plugins all work, although I have only done minimal testing on them. The current tests, such as they are, all

Another interesting thing you can do with this plugin: https://rwmj.wordpress.com/2019/02/19/nbdkit-linuxdisk-plugin/ v2: - Fix inconsistent tab/space. - All 3 plugins now contain a block of text pointing to the other 2 plugins. - TMDIR -> TMPDIR - Unlink the temporary file and other cleanups along error paths. - fclose -> pclose, and check the return value for errors. -

Turns out Japanese trains are good for coding! In supermin we have a bunch of code to create the libguestfs appliance. It creates it directly using libext2fs (part of e2fsprogs). We can use the same technique to create ext2 virtual disks in nbdkit, which is what this new plugin does. Why a new plugin instead of modifying the floppy plugin? See the 4/4 commit message for an explanation. The

This is a revised version of the two series previously posted here: https://www.redhat.com/archives/libguestfs/2019-January/msg00137.html https://www.redhat.com/archives/libguestfs/2019-January/msg00139.html There have been many smaller changes but the highlights are: - Using SECTOR_SIZE instead of hard-coding 512 everywhere. - Additional safety checks that the EBR chain doesn't jump