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Add checksum helper functions.

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These functions make it easier to write code that wants to compute a
checksum for some data while allowing the user to configure the type
of checksum that gets used.

This is another piece of infrastructure for the upcoming patch to add
backup manifests.

Patch written from scratch by me, but it is similar to previous work
by Rushabh Lathia and Suraj Kharage. Suraj also reviewed this version
off-list. Advice on how not to break Windows from Davinder Singh.

Discussion: http://postgr.es/m/CA+TgmoZV8dw1H2bzZ9xkKwdrk8+XYa+DC9H=F7heO2zna5T6qg@mail.gmail.com
Discussion: http://postgr.es/m/CA+TgmoZRTBiPyvQEwV79PU1ePTtSEo2UeVncrkJMbn1sU1gnRA@mail.gmail.com
This commit is contained in:
Robert Haas
2020-04-03 11:50:38 -04:00
parent 6dd9f35779
commit c12e43a2e0
4 changed files with 267 additions and 2 deletions
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1
src/common/Makefile
View File

@@ -48,6 +48,7 @@ LIBS += $(PTHREAD_LIBS)
OBJS_COMMON = \
archive.o \
base64.o \
checksum_helper.o \
config_info.o \
controldata_utils.o \
d2s.o \

190
src/common/checksum_helper.c Normal file
View File

@@ -0,0 +1,190 @@
/*-------------------------------------------------------------------------
*
* checksum_helper.c
* Compute a checksum of any of various types using common routines
*
* Portions Copyright (c) 2016-2020, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/common/checksum_helper.c
*
*-------------------------------------------------------------------------
*/
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
#include "common/checksum_helper.h"
/*
* If 'name' is a recognized checksum type, set *type to the corresponding
* constant and return true. Otherwise, set *type to CHECKSUM_TYPE_NONE and
* return false.
*/
bool
pg_checksum_parse_type(char *name, pg_checksum_type *type)
{
pg_checksum_type result_type = CHECKSUM_TYPE_NONE;
bool result = true;
if (pg_strcasecmp(name, "none") == 0)
result_type = CHECKSUM_TYPE_NONE;
else if (pg_strcasecmp(name, "crc32c") == 0)
result_type = CHECKSUM_TYPE_CRC32C;
else if (pg_strcasecmp(name, "sha224") == 0)
result_type = CHECKSUM_TYPE_SHA224;
else if (pg_strcasecmp(name, "sha256") == 0)
result_type = CHECKSUM_TYPE_SHA256;
else if (pg_strcasecmp(name, "sha384") == 0)
result_type = CHECKSUM_TYPE_SHA384;
else if (pg_strcasecmp(name, "sha512") == 0)
result_type = CHECKSUM_TYPE_SHA512;
else
result = false;
*type = result_type;
return result;
}
/*
* Get the canonical human-readable name corresponding to a checksum type.
*/
char *
pg_checksum_type_name(pg_checksum_type type)
{
switch (type)
{
case CHECKSUM_TYPE_NONE:
return "NONE";
case CHECKSUM_TYPE_CRC32C:
return "CRC32C";
case CHECKSUM_TYPE_SHA224:
return "SHA224";
case CHECKSUM_TYPE_SHA256:
return "SHA256";
case CHECKSUM_TYPE_SHA384:
return "SHA384";
case CHECKSUM_TYPE_SHA512:
return "SHA512";
}
Assert(false);
return "???";
}
/*
* Initialize a checksum context for checksums of the given type.
*/
void
pg_checksum_init(pg_checksum_context *context, pg_checksum_type type)
{
context->type = type;
switch (type)
{
case CHECKSUM_TYPE_NONE:
/* do nothing */
break;
case CHECKSUM_TYPE_CRC32C:
INIT_CRC32C(context->raw_context.c_crc32c);
break;
case CHECKSUM_TYPE_SHA224:
pg_sha224_init(&context->raw_context.c_sha224);
break;
case CHECKSUM_TYPE_SHA256:
pg_sha256_init(&context->raw_context.c_sha256);
break;
case CHECKSUM_TYPE_SHA384:
pg_sha384_init(&context->raw_context.c_sha384);
break;
case CHECKSUM_TYPE_SHA512:
pg_sha512_init(&context->raw_context.c_sha512);
break;
}
}
/*
* Update a checksum context with new data.
*/
void
pg_checksum_update(pg_checksum_context *context, const uint8 *input,
size_t len)
{
switch (context->type)
{
case CHECKSUM_TYPE_NONE:
/* do nothing */
break;
case CHECKSUM_TYPE_CRC32C:
COMP_CRC32C(context->raw_context.c_crc32c, input, len);
break;
case CHECKSUM_TYPE_SHA224:
pg_sha224_update(&context->raw_context.c_sha224, input, len);
break;
case CHECKSUM_TYPE_SHA256:
pg_sha256_update(&context->raw_context.c_sha256, input, len);
break;
case CHECKSUM_TYPE_SHA384:
pg_sha384_update(&context->raw_context.c_sha384, input, len);
break;
case CHECKSUM_TYPE_SHA512:
pg_sha512_update(&context->raw_context.c_sha512, input, len);
break;
}
}
/*
* Finalize a checksum computation and write the result to an output buffer.
*
* The caller must ensure that the buffer is at least PG_CHECKSUM_MAX_LENGTH
* bytes in length. The return value is the number of bytes actually written.
*/
int
pg_checksum_final(pg_checksum_context *context, uint8 *output)
{
int retval = 0;
StaticAssertStmt(sizeof(pg_crc32c) <= PG_CHECKSUM_MAX_LENGTH,
"CRC-32C digest too big for PG_CHECKSUM_MAX_LENGTH");
StaticAssertStmt(PG_SHA224_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
"SHA224 digest too for PG_CHECKSUM_MAX_LENGTH");
StaticAssertStmt(PG_SHA256_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
"SHA256 digest too for PG_CHECKSUM_MAX_LENGTH");
StaticAssertStmt(PG_SHA384_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
"SHA384 digest too for PG_CHECKSUM_MAX_LENGTH");
StaticAssertStmt(PG_SHA512_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
"SHA512 digest too for PG_CHECKSUM_MAX_LENGTH");
switch (context->type)
{
case CHECKSUM_TYPE_NONE:
break;
case CHECKSUM_TYPE_CRC32C:
FIN_CRC32C(context->raw_context.c_crc32c);
retval = sizeof(pg_crc32c);
memcpy(output, &context->raw_context.c_crc32c, retval);
break;
case CHECKSUM_TYPE_SHA224:
pg_sha224_final(&context->raw_context.c_sha224, output);
retval = PG_SHA224_DIGEST_LENGTH;
break;
case CHECKSUM_TYPE_SHA256:
pg_sha256_final(&context->raw_context.c_sha256, output);
retval = PG_SHA256_DIGEST_LENGTH;
break;
case CHECKSUM_TYPE_SHA384:
pg_sha384_final(&context->raw_context.c_sha384, output);
retval = PG_SHA384_DIGEST_LENGTH;
break;
case CHECKSUM_TYPE_SHA512:
pg_sha512_final(&context->raw_context.c_sha512, output);
retval = PG_SHA512_DIGEST_LENGTH;
break;
}
Assert(retval <= PG_CHECKSUM_MAX_LENGTH);
return retval;
}