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Diffstat (limited to 'src/core/ext/census/resource.c')
| -rw-r--r-- | src/core/ext/census/resource.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/src/core/ext/census/resource.c b/src/core/ext/census/resource.c new file mode 100644 index 0000000000..ed44f004f9 --- /dev/null +++ b/src/core/ext/census/resource.c @@ -0,0 +1,312 @@ +/* + * + * Copyright 2016, Google Inc. + * All rights reserved. + * + * 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. + * * Neither the name of Google Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * 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 + * OWNER 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. + * + */ + +#include "src/core/ext/census/resource.h" +#include "third_party/nanopb/pb_decode.h" + +#include <grpc/census.h> +#include <grpc/support/alloc.h> +#include <grpc/support/log.h> +#include <grpc/support/sync.h> + +#include <stdbool.h> +#include <string.h> + +// Protect local resource data structures. +static gpr_mu resource_lock; + +// Deleteing and creating resources are relatively rare events, and should not +// be done in the critical path of performance sensitive code. We record +// current resource id's used in a simple array, and just search it each time +// we need to assign a new id, or look up a resource. +static resource **resources = NULL; + +// Number of entries in *resources +static size_t n_resources = 0; + +// Number of defined resources +static size_t n_defined_resources = 0; + +void initialize_resources(void) { + gpr_mu_init(&resource_lock); + gpr_mu_lock(&resource_lock); + GPR_ASSERT(resources == NULL && n_resources == 0 && n_defined_resources == 0); + gpr_mu_unlock(&resource_lock); +} + +// Delete a resource given it's ID. The ID must be a valid resource ID. Must be +// called with resource_lock held. +static void delete_resource_locked(size_t rid) { + GPR_ASSERT(resources[rid] != NULL); + gpr_free(resources[rid]->name); + gpr_free(resources[rid]->description); + gpr_free(resources[rid]->numerators); + gpr_free(resources[rid]->denominators); + gpr_free(resources[rid]); + resources[rid] = NULL; + n_defined_resources--; +} + +void shutdown_resources(void) { + gpr_mu_lock(&resource_lock); + for (size_t i = 0; i < n_resources; i++) { + if (resources[i] != NULL) { + delete_resource_locked(i); + } + } + GPR_ASSERT(n_defined_resources == 0); + gpr_free(resources); + resources = NULL; + n_resources = 0; + gpr_mu_unlock(&resource_lock); +} + +// Check the contents of string fields in a resource proto. +static bool validate_string(pb_istream_t *stream, const pb_field_t *field, + void **arg) { + resource *vresource = (resource *)*arg; + switch (field->tag) { + case google_census_Resource_name_tag: + // Name must have at least one character + if (stream->bytes_left == 0) { + gpr_log(GPR_INFO, "Zero-length Resource name."); + return false; + } + vresource->name = gpr_malloc(stream->bytes_left + 1); + vresource->name[stream->bytes_left] = '\0'; + if (!pb_read(stream, (uint8_t *)vresource->name, stream->bytes_left)) { + return false; + } + // Can't have same name as an existing resource. + for (size_t i = 0; i < n_resources; i++) { + resource *compare = resources[i]; + if (compare == vresource || compare == NULL) continue; + if (strcmp(compare->name, vresource->name) == 0) { + gpr_log(GPR_INFO, "Duplicate Resource name %s.", vresource->name); + return false; + } + } + break; + case google_census_Resource_description_tag: + if (stream->bytes_left == 0) { + return true; + } + vresource->description = gpr_malloc(stream->bytes_left + 1); + vresource->description[stream->bytes_left] = '\0'; + if (!pb_read(stream, (uint8_t *)vresource->description, + stream->bytes_left)) { + return false; + } + break; + default: + // No other string fields in Resource. Print warning and skip. + gpr_log(GPR_INFO, "Unknown string field type in Resource protobuf."); + if (!pb_read(stream, NULL, stream->bytes_left)) { + return false; + } + break; + } + return true; +} + +// Decode numerators/denominators in a stream. The `count` and `bup` +// (BasicUnit pointer) are pointers to the approriate fields in a resource +// struct. +static bool validate_units_helper(pb_istream_t *stream, int *count, + google_census_Resource_BasicUnit **bup) { + while (stream->bytes_left) { + (*count)++; + // Have to allocate a new array of values. Normal case is 0 or 1, so + // this should normally not be an issue. + google_census_Resource_BasicUnit *new_bup = + gpr_malloc((size_t)*count * sizeof(google_census_Resource_BasicUnit)); + if (*count != 1) { + memcpy(new_bup, *bup, + (size_t)(*count - 1) * sizeof(google_census_Resource_BasicUnit)); + gpr_free(*bup); + } + *bup = new_bup; + uint64_t value; + if (!pb_decode_varint(stream, &value)) { + return false; + } + *(*bup + *count - 1) = (google_census_Resource_BasicUnit)value; + } + return true; +} + +// Validate units field of a Resource proto. +static bool validate_units(pb_istream_t *stream, const pb_field_t *field, + void **arg) { + resource *vresource = (resource *)(*arg); + switch (field->tag) { + case google_census_Resource_MeasurementUnit_numerator_tag: + return validate_units_helper(stream, &vresource->n_numerators, + &vresource->numerators); + break; + case google_census_Resource_MeasurementUnit_denominator_tag: + return validate_units_helper(stream, &vresource->n_denominators, + &vresource->denominators); + break; + default: + gpr_log(GPR_ERROR, "Unknown field type."); + return false; + break; + } + return true; +} + +// Validate the contents of a Resource proto. `id` is the intended resource id. +static bool validate_resource_pb(const uint8_t *resource_pb, + size_t resource_pb_size, size_t id) { + GPR_ASSERT(id < n_resources); + if (resource_pb == NULL) { + return false; + } + google_census_Resource vresource; + vresource.name.funcs.decode = &validate_string; + vresource.name.arg = resources[id]; + vresource.description.funcs.decode = &validate_string; + vresource.description.arg = resources[id]; + vresource.unit.numerator.funcs.decode = &validate_units; + vresource.unit.numerator.arg = resources[id]; + vresource.unit.denominator.funcs.decode = &validate_units; + vresource.unit.denominator.arg = resources[id]; + + pb_istream_t stream = + pb_istream_from_buffer((uint8_t *)resource_pb, resource_pb_size); + if (!pb_decode(&stream, google_census_Resource_fields, &vresource)) { + return false; + } + // A Resource must have a name, a unit, with at least one numerator. + return (resources[id]->name != NULL && vresource.has_unit && + resources[id]->n_numerators > 0); +} + +// Allocate a blank resource, and return associated ID. Must be called with +// resource_lock held. +size_t allocate_resource(void) { + // use next_id to optimize expected placement of next new resource. + static size_t next_id = 0; + size_t id = n_resources; // resource ID - initialize to invalid value. + // Expand resources if needed. + if (n_resources == n_defined_resources) { + size_t new_n_resources = n_resources ? n_resources * 2 : 2; + resource **new_resources = gpr_malloc(new_n_resources * sizeof(resource *)); + memcpy(new_resources, resources, n_resources * sizeof(resource *)); + memset(new_resources + n_resources, 0, + (new_n_resources - n_resources) * sizeof(resource *)); + gpr_free(resources); + resources = new_resources; + n_resources = new_n_resources; + id = n_defined_resources; + } else { + GPR_ASSERT(n_defined_resources < n_resources); + // Find a free id. + for (size_t base = 0; base < n_resources; base++) { + id = (next_id + base) % n_resources; + if (resources[id] == NULL) break; + } + } + GPR_ASSERT(id < n_resources && resources[id] == NULL); + resources[id] = gpr_malloc(sizeof(resource)); + memset(resources[id], 0, sizeof(resource)); + n_defined_resources++; + next_id = (id + 1) % n_resources; + return id; +} + +int32_t census_define_resource(const uint8_t *resource_pb, + size_t resource_pb_size) { + if (resource_pb == NULL) { + return -1; + } + gpr_mu_lock(&resource_lock); + size_t id = allocate_resource(); + // Validate pb, extract name. + if (!validate_resource_pb(resource_pb, resource_pb_size, id)) { + delete_resource_locked(id); + gpr_mu_unlock(&resource_lock); + return -1; + } + gpr_mu_unlock(&resource_lock); + return (int32_t)id; +} + +void census_delete_resource(int32_t rid) { + gpr_mu_lock(&resource_lock); + if (rid >= 0 && (size_t)rid < n_resources && resources[rid] != NULL) { + delete_resource_locked((size_t)rid); + } + gpr_mu_unlock(&resource_lock); +} + +int32_t census_resource_id(const char *name) { + gpr_mu_lock(&resource_lock); + for (int32_t id = 0; (size_t)id < n_resources; id++) { + if (resources[id] != NULL && strcmp(resources[id]->name, name) == 0) { + gpr_mu_unlock(&resource_lock); + return id; + } + } + gpr_mu_unlock(&resource_lock); + return -1; +} + +int32_t define_resource(const resource *base) { + GPR_ASSERT(base != NULL && base->name != NULL && base->n_numerators > 0 && + base->numerators != NULL); + gpr_mu_lock(&resource_lock); + size_t id = allocate_resource(); + size_t len = strlen(base->name) + 1; + resources[id]->name = gpr_malloc(len); + memcpy(resources[id]->name, base->name, len); + if (base->description) { + len = strlen(base->description) + 1; + resources[id]->description = gpr_malloc(len); + memcpy(resources[id]->description, base->description, len); + } + resources[id]->prefix = base->prefix; + resources[id]->n_numerators = base->n_numerators; + len = (size_t)base->n_numerators * sizeof(*base->numerators); + resources[id]->numerators = gpr_malloc(len); + memcpy(resources[id]->numerators, base->numerators, len); + resources[id]->n_denominators = base->n_denominators; + if (base->n_denominators != 0) { + len = (size_t)base->n_denominators * sizeof(*base->denominators); + resources[id]->denominators = gpr_malloc(len); + memcpy(resources[id]->denominators, base->denominators, len); + } + gpr_mu_unlock(&resource_lock); + return (int32_t)id; +} |