/*
* Copyright 2014 Tushar Gohad, Kevin M Greenan, Eric Lambert, Mark Storer
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY
* THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* liberasurecode API implementation
*
* vi: set noai tw=79 ts=4 sw=4:
*/
#include "list.h"
#include "erasurecode.h"
#include "erasurecode_backend.h"
#include "erasurecode_helpers.h"
#include "erasurecode_helpers_ext.h"
#include "erasurecode_preprocessing.h"
#include "erasurecode_postprocessing.h"
#include "erasurecode_stdinc.h"
#include "alg_sig.h"
#include "erasurecode_log.h"
/* =~=*=~==~=*=~==~=*=~= Supported EC backends =~=*=~==~=*=~==~=*=~==~=*=~== */
/* EC backend references */
extern struct ec_backend_common backend_null;
extern struct ec_backend_common backend_flat_xor_hd;
extern struct ec_backend_common backend_jerasure_rs_vand;
extern struct ec_backend_common backend_jerasure_rs_cauchy;
extern struct ec_backend_common backend_isa_l_rs_vand;
extern struct ec_backend_common backend_shss;
extern struct ec_backend_common backend_liberasurecode_rs_vand;
ec_backend_t ec_backends_supported[] = {
(ec_backend_t) &backend_null,
(ec_backend_t) &backend_jerasure_rs_vand,
(ec_backend_t) &backend_jerasure_rs_cauchy,
(ec_backend_t) &backend_flat_xor_hd,
(ec_backend_t) &backend_isa_l_rs_vand,
(ec_backend_t) &backend_shss,
(ec_backend_t) &backend_liberasurecode_rs_vand,
NULL,
};
/* backend list to return to the caller */
int num_supported_backends = 0;
char *ec_backends_supported_str[EC_BACKENDS_MAX];
/* =~=*=~==~=*=~==~=*=~= EC backend instance management =~=*=~==~=*=~==~=*= */
/* Registered erasure code backend instances */
SLIST_HEAD(backend_list, ec_backend) active_instances =
SLIST_HEAD_INITIALIZER(active_instances);
rwlock_t active_instances_rwlock = RWLOCK_INITIALIZER;
/* Backend instance id */
int next_backend_desc = 0;
/**
* Look up a backend instance by descriptor
*
* @returns pointer to a registered liberasurecode instance
* The caller must hold active_instances_rwlock
*/
ec_backend_t liberasurecode_backend_instance_get_by_desc(int desc)
{
struct ec_backend *b = NULL;
SLIST_FOREACH(b, &active_instances, link) {
if (b->idesc == desc)
break;
}
return b;
}
/**
* Allocated backend instance descriptor
*
* Returns a unique descriptor for a new backend.
* The caller must hold active_instances_rwlock
*/
int liberasurecode_backend_alloc_desc(void)
{
for (;;) {
if (++next_backend_desc <= 0)
next_backend_desc = 1;
if (!liberasurecode_backend_instance_get_by_desc(next_backend_desc))
return next_backend_desc;
}
}
/**
* Register a backend instance with liberasurecode
*
* @param instance - backend enum
*
* @returns new backend descriptor
*/
int liberasurecode_backend_instance_register(ec_backend_t instance)
{
int desc = -1; /* descriptor to return */
int rc = 0; /* return call value */
rc = rwlock_wrlock(&active_instances_rwlock);
if (rc == 0) {
SLIST_INSERT_HEAD(&active_instances, instance, link);
desc = liberasurecode_backend_alloc_desc();
if (desc <= 0)
goto register_out;
instance->idesc = desc;
} else {
goto exit;
}
register_out:
rwlock_unlock(&active_instances_rwlock);
exit:
return desc;
}
/**
* Unregister a backend instance
*
* @returns 0 on success, non-0 on error
*/
int liberasurecode_backend_instance_unregister(ec_backend_t instance)
{
int rc = 0; /* return call value */
rc = rwlock_wrlock(&active_instances_rwlock);
if (rc == 0) {
SLIST_REMOVE(&active_instances, instance, ec_backend, link);
} else {
goto exit;
}
rwlock_unlock(&active_instances_rwlock);
exit:
return rc;
}
/* =~=*=~==~=*=~== liberasurecode backend API helpers =~=*=~==~=*=~== */
static void print_dlerror(const char *caller)
{
char *msg = dlerror();
if (NULL == msg)
log_error("%s: unknown dynamic linking error\n", caller);
else
log_error("%s: dynamic linking error %s\n", caller, msg);
}
/* Generic dlopen/dlclose routines */
int liberasurecode_backend_open(ec_backend_t instance)
{
if (instance && NULL != instance->desc.backend_sohandle)
return 0;
/* Use RTLD_LOCAL to avoid symbol collisions */
instance->desc.backend_sohandle = dlopen(instance->common.soname,
RTLD_LAZY | RTLD_LOCAL);
if (NULL == instance->desc.backend_sohandle) {
print_dlerror(__func__);
return -EBACKENDNOTAVAIL;
}
dlerror(); /* Clear any existing errors */
return 0;
}
int liberasurecode_backend_close(ec_backend_t instance)
{
if (NULL == instance || NULL == instance->desc.backend_sohandle)
return 0;
dlclose(instance->desc.backend_sohandle);
dlerror(); /* Clear any existing errors */
instance->desc.backend_sohandle = NULL;
return 0;
}
/* =*=~==~=*=~==~=*=~= liberasurecode init/exit routines =~=*=~==~=*=~==~=*= */
void __attribute__ ((constructor))
liberasurecode_init(void) {
/* init logging */
openlog("liberasurecode", LOG_PID | LOG_CONS | LOG_NDELAY | LOG_PERROR, LOG_USER);
/* populate supported backends list as a string */
{
int i;
for (i = 0; ec_backends_supported[i]; ++i) {
ec_backends_supported_str[i] = strdup(
ec_backends_supported[i]->common.name);
}
num_supported_backends = i;
}
}
void __attribute__ ((destructor))
liberasurecode_exit(void) {
int i;
for (i = 0; i < num_supported_backends; ++i)
free(ec_backends_supported_str[i]);
closelog();
}
/* =~=*=~==~=*=~= liberasurecode frontend API implementation =~=*=~==~=*=~== */
/**
* Create a liberasurecode instance and return a descriptor
* for use with EC operations (encode, decode, reconstruct)
*
* @param id - one of the supported backends as
* defined by ec_backend_id_t
* @param ec_args - arguments to the EC backend
* arguments common to all backends
* k - number of data fragments
* m - number of parity fragments
* w - word size, in bits
* hd - hamming distance (=m for Reed-Solomon)
* ct - fragment checksum type (stored with the fragment metadata)
* backend-specific arguments
* null_args - arguments for the null backend
* flat_xor_hd, jerasure do not require any special args
*
* @returns liberasurecode instance descriptor (int > 0)
*/
int liberasurecode_instance_create(const ec_backend_id_t id,
struct ec_args *args)
{
int err = 0;
ec_backend_t instance = NULL;
struct ec_backend_args bargs;
if (!args)
return -EINVALIDPARAMS;
if (id >= EC_BACKENDS_MAX)
return -EBACKENDNOTSUPP;
if ((args->k + args->m) > EC_MAX_FRAGMENTS) {
log_error("Total number of fragments (k + m) must be less than %d\n",
EC_MAX_FRAGMENTS);
return -EINVALIDPARAMS;
}
/* Allocate memory for ec_backend instance */
instance = calloc(1, sizeof(*instance));
if (NULL == instance)
return -ENOMEM;
/* Copy common backend, args struct */
instance->common = ec_backends_supported[id]->common;
memcpy(&(bargs.uargs), args, sizeof (struct ec_args));
instance->args = bargs;
/* Open backend .so if not already open */
/* .so handle is returned in instance->desc.backend_sohandle */
err = liberasurecode_backend_open(instance);
if (err < 0) {
/* ignore during init, return the same handle */
free(instance);
return err;
}
/* Call private init() for the backend */
instance->desc.backend_desc = instance->common.ops->init(
&instance->args, instance->desc.backend_sohandle);
if (NULL == instance->desc.backend_desc) {
free (instance);
return -EBACKENDINITERR;
}
/* Register instance and return a descriptor/instance id */
instance->idesc = liberasurecode_backend_instance_register(instance);
return instance->idesc;
}
/**
* Close a liberasurecode instance
*
* @param liberasurecode descriptor to close
*/
int liberasurecode_instance_destroy(int desc)
{
ec_backend_t instance = NULL; /* instance to destroy */
int rc = 0; /* return code */
instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance)
return -EBACKENDNOTAVAIL;
/* Call private exit() for the backend */
instance->common.ops->exit(instance->desc.backend_desc);
/* dlclose() backend library */
liberasurecode_backend_close(instance);
/* Remove instace from registry */
rc = liberasurecode_backend_instance_unregister(instance);
if (rc == 0) {
free(instance);
}
return rc;
}
/**
* Cleanup structures allocated by librasurecode_encode
*
* The caller has no context, so cannot safely free memory
* allocated by liberasurecode, so it must pass the
* deallocation responsibility back to liberasurecode.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param encoded_data - (char **) array of k data
* fragments (char *), allocated by liberasurecode_encode
* @param encoded_parity - (char **) array of m parity
* fragments (char *), allocated by liberasurecode_encode
* @return 0 in success; -error otherwise
*/
int liberasurecode_encode_cleanup(int desc,
char **encoded_data,
char **encoded_parity)
{
int i, k, m;
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
return -EBACKENDNOTAVAIL;
}
k = instance->args.uargs.k;
m = instance->args.uargs.m;
if (encoded_data) {
for (i = 0; i < k; i++) {
free(encoded_data[i]);
}
free(encoded_data);
}
if (encoded_parity) {
for (i = 0; i < m; i++) {
free(encoded_parity[i]);
}
free(encoded_parity);
}
return 0;
}
/**
* Erasure encode a data buffer
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param orig_data - data to encode
* @param orig_data_size - length of data to encode
* @param encoded_data - pointer to _output_ array (char **) of k data
* fragments (char *), allocated by the callee
* @param encoded_parity - pointer to _output_ array (char **) of m parity
* fragments (char *), allocated by the callee
* @param fragment_len - pointer to _output_ length of each fragment, assuming
* all fragments are the same length
*
* @return 0 on success, -error code otherwise
*/
int liberasurecode_encode(int desc,
const char *orig_data, uint64_t orig_data_size, /* input */
char ***encoded_data, char ***encoded_parity, /* output */
uint64_t *fragment_len) /* output */
{
int k, m;
int ret = 0; /* return code */
int blocksize = 0; /* length of each of k data elements */
if (orig_data == NULL) {
log_error("Pointer to data buffer is null!");
ret = -EINVALIDPARAMS;
goto out;
}
if (encoded_data == NULL) {
log_error("Pointer to encoded data buffers is null!");
return -EINVALIDPARAMS;
}
if (encoded_parity == NULL) {
log_error("Pointer to encoded parity buffers is null!");
return -EINVALIDPARAMS;
}
if (fragment_len == NULL) {
log_error("Pointer to fragment length is null!");
ret = -EINVALIDPARAMS;
goto out;
}
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
ret = -EBACKENDNOTAVAIL;
goto out;
}
k = instance->args.uargs.k;
m = instance->args.uargs.m;
/*
* Allocate arrays for data, parity and missing_idxs
*/
*encoded_data = (char **) alloc_zeroed_buffer(sizeof(char *) * k);
if (NULL == *encoded_data) {
log_error("Could not allocate data buffer!");
goto out;
}
*encoded_parity = (char **) alloc_zeroed_buffer(sizeof(char *) * m);
if (NULL == *encoded_parity) {
log_error("Could not allocate parity buffer!");
goto out;
}
ret = prepare_fragments_for_encode(instance, k, m, orig_data, orig_data_size,
*encoded_data, *encoded_parity, &blocksize);
if (ret < 0) {
// ensure encoded_data/parity point the head of fragment_ptr
get_fragment_ptr_array_from_data(*encoded_data, *encoded_data, k);
get_fragment_ptr_array_from_data(*encoded_parity, *encoded_parity, m);
goto out;
}
/* call the backend encode function passing it desc instance */
ret = instance->common.ops->encode(instance->desc.backend_desc,
*encoded_data, *encoded_parity, blocksize);
if (ret < 0) {
// ensure encoded_data/parity point the head of fragment_ptr
get_fragment_ptr_array_from_data(*encoded_data, *encoded_data, k);
get_fragment_ptr_array_from_data(*encoded_parity, *encoded_parity, m);
goto out;
}
ret = finalize_fragments_after_encode(instance, k, m, blocksize, orig_data_size,
*encoded_data, *encoded_parity);
*fragment_len = get_fragment_size((*encoded_data)[0]);
out:
if (ret) {
/* Cleanup the allocations we have done */
liberasurecode_encode_cleanup(desc, *encoded_data, *encoded_parity);
log_error("Error in liberasurecode_encode %d", ret);
}
return ret;
}
/**
* Cleanup structures allocated by librasurecode_decode
*
* The caller has no context, so cannot safely free memory
* allocated by liberasurecode, so it must pass the
* deallocation responsibility back to liberasurecode.
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param data - (char *) buffer of data decoded by
* librasurecode_decode
* @return 0 in success; -error otherwise
*/
int liberasurecode_decode_cleanup(int desc, char *data)
{
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
return -EBACKENDNOTAVAIL;
}
free(data);
return 0;
}
/**
* Reconstruct original data from a set of k encoded fragments
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param fragments - erasure encoded fragments (> = k)
* @param num_fragments - number of fragments being passed in
* @param fragment_len - length of each fragment (assume they are the same)
* @param force_metadata_checks - force fragment metadata checks (default: 0)
* @param out_data - _output_ pointer to decoded data
* @param out_data_len - _output_ length of decoded output
* @return 0 on success, -error code otherwise
*/
int liberasurecode_decode(int desc,
char **available_fragments, /* input */
int num_fragments, uint64_t fragment_len, /* input */
int force_metadata_checks, /* input */
char **out_data, uint64_t *out_data_len) /* output */
{
int i, j;
int ret = 0;
int k = -1, m = -1;
int orig_data_size = 0;
int blocksize = 0;
char **data = NULL;
char **parity = NULL;
char **data_segments = NULL;
char **parity_segments = NULL;
int *missing_idxs = NULL;
uint64_t realloc_bm = 0;
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
ret = -EBACKENDNOTAVAIL;
goto out;
}
if (NULL == available_fragments) {
log_error("Pointer to encoded fragments buffer is null!");
ret = -EINVALIDPARAMS;
goto out;
}
if (NULL == out_data) {
log_error("Pointer to decoded data buffer is null!");
ret = -EINVALIDPARAMS;
goto out;
}
if (NULL == out_data_len) {
log_error("Pointer to decoded data length variable is null!");
ret = -EINVALIDPARAMS;
goto out;
}
k = instance->args.uargs.k;
m = instance->args.uargs.m;
if (num_fragments < k) {
ret = -EINSUFFFRAGS;
goto out;
}
if (instance->common.id != EC_BACKEND_SHSS) {
/* shss (ntt_backend) must force to decode */
// TODO: Add a frag and function to handle whether the backend want to decode or not.
/*
* Try to re-assebmle the original data before attempting a decode
*/
ret = fragments_to_string(k, m,
available_fragments, num_fragments,
out_data, out_data_len);
if (ret == 0) {
/* We were able to get the original data without decoding! */
goto out;
}
}
/*
* Allocate arrays for data, parity and missing_idxs
*/
data = alloc_zeroed_buffer(sizeof(char*) * k);
if (NULL == data) {
log_error("Could not allocate data buffer!");
goto out;
}
parity = alloc_zeroed_buffer(sizeof(char*) * m);
if (NULL == parity) {
log_error("Could not allocate parity buffer!");
goto out;
}
missing_idxs = alloc_and_set_buffer(sizeof(char*) * (k + m), -1);
if (NULL == missing_idxs) {
log_error("Could not allocate missing_idxs buffer!");
goto out;
}
/* If metadata checks requested, check fragment integrity upfront */
if (force_metadata_checks) {
int num_invalid_fragments = 0;
for (i = 0; i < num_fragments; ++i) {
if (is_invalid_fragment(desc, available_fragments[i])) {
++num_invalid_fragments;
}
}
if ((num_fragments - num_invalid_fragments) < k) {
ret = -EINSUFFFRAGS;
log_error("Not enough valid fragments available for decode!");
goto out;
}
}
/*
* Separate the fragments into data and parity. Also determine which
* pieces are missing.
*/
ret = get_fragment_partition(k, m, available_fragments, num_fragments,
data, parity, missing_idxs);
if (ret < 0) {
log_error("Could not properly partition the fragments!");
goto out;
}
/*
* Preparing the fragments for decode. This will alloc aligned buffers
* when unaligned buffers were passed in available_fragments. It passes
* back a bitmap telling us which buffers need to be freed by us
* (realloc_bm).
*
*/
ret = prepare_fragments_for_decode(k, m,
data, parity, missing_idxs,
&orig_data_size, &blocksize,
fragment_len, &realloc_bm);
if (ret < 0) {
log_error("Could not prepare fragments for decode!");
goto out;
}
data_segments = alloc_zeroed_buffer(k * sizeof(char *));
parity_segments = alloc_zeroed_buffer(m * sizeof(char *));
get_data_ptr_array_from_fragments(data_segments, data, k);
get_data_ptr_array_from_fragments(parity_segments, parity, m);
/* call the backend decode function passing it desc instance */
ret = instance->common.ops->decode(instance->desc.backend_desc,
data_segments, parity_segments,
missing_idxs, blocksize);
if (ret < 0) {
log_error("Encountered error in backend decode function!");
goto out;
}
/*
* Need to fill in the missing data headers so we can generate
* the original string.
*/
j = 0;
while (missing_idxs[j] >= 0) {
int set_chksum = 1;
int missing_idx = missing_idxs[j];
if (missing_idx < k) {
/* Generate headers */
char *fragment_ptr = data[missing_idx];
init_fragment_header(fragment_ptr);
add_fragment_metadata(instance, fragment_ptr, missing_idx,
orig_data_size, blocksize, instance->args.uargs.ct,
!set_chksum);
}
j++;
}
/* Try to generate the original string */
ret = fragments_to_string(k, m, data, k, out_data, out_data_len);
if (ret < 0) {
log_error("Could not convert decoded fragments to a string!");
}
out:
/* Free the buffers allocated in prepare_fragments_for_decode */
if (realloc_bm != 0) {
for (i = 0; i < k; i++) {
if (realloc_bm & (1 << i)) {
free(data[i]);
}
}
for (i = 0; i < m; i++) {
if (realloc_bm & (1 << (i + k))) {
free(parity[i]);
}
}
}
free(data);
free(parity);
free(missing_idxs);
free(data_segments);
free(parity_segments);
return ret;
}
/**
* Reconstruct a missing fragment from a subset of available fragments
*
* @param desc - liberasurecode descriptor/handle
* from liberasurecode_instance_create()
* @param fragment_len - size in bytes of the fragments
* @param available_fragments - erasure encoded fragments
* @param num_fragments - number of fragments being passed in
* @param destination_idx - missing idx to reconstruct
* @param out_fragment - output of reconstruct
* @return 0 on success, -error code otherwise
*/
int liberasurecode_reconstruct_fragment(int desc,
char **available_fragments, /* input */
int num_fragments, uint64_t fragment_len, /* input */
int destination_idx, /* input */
char* out_fragment) /* output */
{
int ret = 0;
int blocksize = 0;
int orig_data_size = 0;
char **data = NULL;
char **parity = NULL;
int *missing_idxs = NULL;
char *fragment_ptr = NULL;
int is_destination_missing = 0;
int k = -1;
int m = -1;
int i;
uint64_t realloc_bm = 0;
char **data_segments = NULL;
char **parity_segments = NULL;
int set_chksum = 1;
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
ret = -EBACKENDNOTAVAIL;
goto out;
}
if (NULL == available_fragments) {
log_error("Can not reconstruct fragment, available fragments pointer is NULL");
ret = -EINVALIDPARAMS;
goto out;
}
if (NULL == out_fragment) {
log_error("Can not reconstruct fragment, output fragment pointer is NULL");
ret = -EINVALIDPARAMS;
goto out;
}
k = instance->args.uargs.k;
m = instance->args.uargs.m;
/*
* Allocate arrays for data, parity and missing_idxs
*/
data = alloc_zeroed_buffer(sizeof(char*) * k);
if (NULL == data) {
log_error("Could not allocate data buffer!");
goto out;
}
parity = alloc_zeroed_buffer(sizeof(char*) * m);
if (NULL == parity) {
log_error("Could not allocate parity buffer!");
goto out;
}
missing_idxs = alloc_and_set_buffer(sizeof(int*) * (k + m), -1);
if (NULL == missing_idxs) {
log_error("Could not allocate missing_idxs buffer!");
goto out;
}
/*
* Separate the fragments into data and parity. Also determine which
* pieces are missing.
*/
ret = get_fragment_partition(k, m, available_fragments, num_fragments,
data, parity, missing_idxs);
if (ret < 0) {
log_error("Could not properly partition the fragments!");
goto out;
}
/*
* Odd corner-case: If the caller passes in a destination_idx that
* is also included in the available fragments list, we should *not*
* try to reconstruct.
*
* For now, we will log a warning and do nothing. In the future, we
* should probably log and return an error.
*
*/
i = 0;
while (missing_idxs[i] > -1) {
if (missing_idxs[i] == destination_idx) {
is_destination_missing = 1;
}
i++;
}
if (!is_destination_missing) {
if (destination_idx < k) {
fragment_ptr = data[destination_idx];
} else {
fragment_ptr = parity[destination_idx - k];
}
log_warn("Dest idx for reconstruction was supplied as available buffer!");
goto destination_available;
}
/*
* Preparing the fragments for reconstruction. This will alloc aligned
* buffers when unaligned buffers were passed in available_fragments.
* It passes back a bitmap telling us which buffers need to be freed by
* us (realloc_bm).
*/
ret = prepare_fragments_for_decode(k, m, data, parity, missing_idxs,
&orig_data_size, &blocksize,
fragment_len, &realloc_bm);
if (ret < 0) {
log_error("Could not prepare fragments for reconstruction!");
goto out;
}
data_segments = alloc_zeroed_buffer(k * sizeof(char *));
parity_segments = alloc_zeroed_buffer(m * sizeof(char *));
get_data_ptr_array_from_fragments(data_segments, data, k);
get_data_ptr_array_from_fragments(parity_segments, parity, m);
/* call the backend reconstruct function passing it desc instance */
ret = instance->common.ops->reconstruct(instance->desc.backend_desc,
data_segments, parity_segments,
missing_idxs, destination_idx,
blocksize);
if (ret < 0) {
log_error("Could not reconstruct fragment!");
goto out;
}
/*
* Update the header to reflect the newly constructed fragment
*/
if (destination_idx < k) {
fragment_ptr = data[destination_idx];
} else {
fragment_ptr = parity[destination_idx - k];
}
init_fragment_header(fragment_ptr);
add_fragment_metadata(instance, fragment_ptr, destination_idx,
orig_data_size, blocksize, instance->args.uargs.ct,
set_chksum);
destination_available:
/*
* Copy the reconstructed fragment to the output buffer
*
* Note: the address stored in fragment_ptr will be freed below
*/
memcpy(out_fragment, fragment_ptr, fragment_len);
out:
/* Free the buffers allocated in prepare_fragments_for_decode */
if (realloc_bm != 0) {
for (i = 0; i < k; i++) {
if (realloc_bm & (1 << i)) {
free(data[i]);
}
}
for (i = 0; i < m; i++) {
if (realloc_bm & (1 << (i + k))) {
free(parity[i]);
}
}
}
free(data);
free(parity);
free(missing_idxs);
free(data_segments);
free(parity_segments);
return ret;
}
/**
* Return a list of lists with valid rebuild indexes given
* a list of missing indexes.
*
* @desc: liberasurecode instance descriptor (obtained with
* liberasurecode_instance_create)
* @fragments_to_reconstruct list of indexes to reconstruct
* @fragments_to_exclude list of indexes to exclude from
reconstruction equation
* @fragments_needed list of fragments needed to reconstruct
fragments in fragments_to_reconstruct
*
* @return a list of lists (bitmaps) of indexes to rebuild data
* from (in 'fragments_needed')
*/
int liberasurecode_fragments_needed(int desc,
int *fragments_to_reconstruct,
int *fragments_to_exclude,
int *fragments_needed)
{
int ret = 0;
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
ret = -EBACKENDNOTAVAIL;
goto out_error;
}
if (NULL == fragments_to_reconstruct) {
log_error("Unable to determine list of fragments needed, pointer to list of indexes to reconstruct is NULL.");
ret = -EINVALIDPARAMS;
goto out_error;
}
if (NULL == fragments_to_exclude) {
log_error("Unable to determine list of fragments needed, pointer to list of fragments to exclude is NULL.");
ret = -EINVALIDPARAMS;
goto out_error;
}
if (NULL == fragments_needed) {
log_error("Unable to determine list of fragments needed, pointer to list of fragments to reconstruct is NULL.");
ret = -EINVALIDPARAMS;
goto out_error;
}
/* FIXME preprocessing */
/* call the backend fragments_needed function passing it desc instance */
ret = instance->common.ops->fragments_needed(
instance->desc.backend_desc,
fragments_to_reconstruct, fragments_to_exclude, fragments_needed);
out_error:
return ret;
}
/* =~=*=~==~=*=~==~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~= */
/**
* Get opaque metadata for a fragment. The metadata is opaque to the
* client, but meaningful to the underlying library. It is used to verify
* stripes in verify_stripe_metadata().
*
* @param fragment - fragment pointer
*
* @param fragment_metadata - pointer to output fragment metadata struct
* (reference passed by the user)
*/
int liberasurecode_get_fragment_metadata(char *fragment,
fragment_metadata_t *fragment_metadata)
{
int ret = 0;
fragment_header_t *fragment_hdr = NULL;
if (NULL == fragment) {
log_error("Need valid fragment object to get metadata for");
ret = -EINVALIDPARAMS;
goto out;
}
if (NULL == fragment_metadata) {
log_error("Need valid fragment_metadata object for return value");
ret = -EINVALIDPARAMS;
goto out;
}
memcpy(fragment_metadata, fragment, sizeof(struct fragment_metadata));
fragment_hdr = (fragment_header_t *) fragment;
if (LIBERASURECODE_FRAG_HEADER_MAGIC != fragment_hdr->magic) {
log_error("Invalid fragment, illegal magic value");
ret = -EINVALIDPARAMS;
goto out;
}
switch(fragment_hdr->meta.chksum_type) {
case CHKSUM_CRC32: {
uint32_t computed_chksum = 0;
uint32_t stored_chksum = fragment_hdr->meta.chksum[0];
char *fragment_data = get_data_ptr_from_fragment(fragment);
uint64_t fragment_size = fragment_hdr->meta.size;
computed_chksum = crc32(0, fragment_data, fragment_size);
if (stored_chksum != computed_chksum) {
fragment_metadata->chksum_mismatch = 1;
} else {
fragment_metadata->chksum_mismatch = 0;
}
break;
}
case CHKSUM_MD5:
break;
case CHKSUM_NONE:
default:
break;
}
out:
return ret;
}
int liberasurecode_verify_fragment_metadata(ec_backend_t be,
fragment_metadata_t *md)
{
if (md->backend_id != be->common.id) {
return 1;
}
if (!be->common.ops->is_compatible_with(md->backend_version)) {
return 1;
}
return 0;
}
int is_invalid_fragment(int desc, char *fragment)
{
uint32_t ver = 0;
fragment_metadata_t fragment_metadata;
ec_backend_t be = liberasurecode_backend_instance_get_by_desc(desc);
if (!be) {
log_error("Unable to verify fragment metadata: invalid backend id %d.",
desc);
return 1;
}
if (!fragment) {
log_error("Unable to verify fragment validity: fragments missing.");
return 1;
}
if (get_libec_version(fragment, &ver) != 0 ||
ver != LIBERASURECODE_VERSION) {
return 1;
}
if (liberasurecode_get_fragment_metadata(fragment,
&fragment_metadata) != 0) {
return 1;
}
if (liberasurecode_verify_fragment_metadata(be,
&fragment_metadata) != 0) {
return 1;
}
return 0;
}
int is_valid_fragment_metadata(int desc, fragment_metadata_t *fragment_metadata)
{
ec_backend_t be = liberasurecode_backend_instance_get_by_desc(desc);
if (!be) {
log_error("Unable to verify stripe metadata: invalid backend id %d.",
desc);
return -EINVALIDPARAMS;
}
if (liberasurecode_verify_fragment_metadata(be,
fragment_metadata) != 0) {
return -EBADHEADER;
}
if (!be->common.ops->is_compatible_with(fragment_metadata->backend_version)) {
return -EBADHEADER;
}
if (fragment_metadata->chksum_mismatch == 1) {
return -EBADCHKSUM;
}
return 0;
}
int liberasurecode_verify_stripe_metadata(int desc,
char **fragments, int num_fragments)
{
int i = 0;
if (!fragments) {
log_error("Unable to verify stripe metadata: fragments missing.");
return -EINVALIDPARAMS;
}
if (num_fragments <= 0) {
log_error("Unable to verify stripe metadata: "
"number of fragments must be greater than 0.");
return -EINVALIDPARAMS;
}
for (i = 0; i < num_fragments; i++) {
fragment_metadata_t *fragment_metadata = (fragment_metadata_t*)fragments[i];
int ret = is_valid_fragment_metadata(desc, fragment_metadata);
if (ret < 0) {
return ret;
}
}
return 0;
}
/* =~=*=~==~=*=~==~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~= */
/**
* This computes the aligned size of a buffer passed into
* the encode function. The encode function must pad fragments
* to be algined with the word size (w) and the last fragment also
* needs to be aligned. This computes the sum of the algined fragment
* sizes for a given buffer to encode.
*/
int liberasurecode_get_aligned_data_size(int desc, uint64_t data_len)
{
int k;
int ret = 0;
int word_size;
int alignment_multiple;
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
if (NULL == instance) {
ret = -EBACKENDNOTAVAIL;
goto out;
}
k = instance->args.uargs.k;
word_size = instance->common.ops->element_size(
instance->desc.backend_desc) / 8;
alignment_multiple = k * word_size;
ret = (int) ceill( (double)
data_len / alignment_multiple) * alignment_multiple;
out:
return ret;
}
/**
* This will return the minumum encode size, which is the minimum
* buffer size that can be encoded.
*/
int liberasurecode_get_minimum_encode_size(int desc)
{
return liberasurecode_get_aligned_data_size(desc, 1);
}
int liberasurecode_get_fragment_size(int desc, int data_len)
{
ec_backend_t instance = liberasurecode_backend_instance_get_by_desc(desc);
// TODO: Create a common function to calculate fragment size also for preprocessing
int aligned_data_len = get_aligned_data_size(instance, data_len);
int size = (aligned_data_len / instance->args.uargs.k) + instance->common.backend_metadata_size;
return size;
}
/* ==~=*=~==~=*=~==~=*=~==~=*=~==~=* misc *=~==~=*=~==~=*=~==~=*=~==~=*=~== */
#if 0
/* Validate backend before calling init */
int liberasurecode_backend_validate(ec_backend_t backend)
{
/* Verify that the backend implements all required methods */
}
/* FIXME - do we need to use reference counts if we are creating
* a new instance per user */
/* Get a reference to an EC backend */
ec_backend_t liberasurecode_backend_get(const char *name)
{
ec_backend_t b = liberasurecode_backend_lookup_by_name(name);
if (NULL != b)
++b->users;
return b;
}
/* Drop an EC backend reference held */
void liberasurecode_backend_put(ec_backend_t backend)
{
if (backend->users > 0)
--backend->users;
}
/* Query interface for active instances */
ec_backend_t liberasurecode_backend_instance_active(ec_backend_t instance)
{
ec_backend_t b;
SLIST_FOREACH(b, &active_instances, link) {
if (strcmp(b->name, name) == 0)
return b;
}
return NULL;
}
ec_backend_t liberasurecode_backend_lookup_by_soname(const char *soname)
{
ec_backend_t b;
SLIST_FOREACH(b, &active_instances, link) {
if (strcmp(b->soname, soname) == 0)
return b;
}
return NULL;
}
#endif
/* ==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~==~=*=~== */