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- /*
- This file is part of GNUnet.
- Copyright (C) 2001-2013 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- or (at your option) any later version.
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Affero General Public License for more details.
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file util/crypto_hash_file.c
- * @brief incremental hashing of files
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #include <gcrypt.h>
- #define LOG(kind, ...) GNUNET_log_from (kind, "util-crypto-hash-file", \
- __VA_ARGS__)
- #define LOG_STRERROR_FILE(kind, syscall, \
- filename) GNUNET_log_from_strerror_file (kind, \
- "util-crypto-hash-file", \
- syscall, \
- filename)
- /**
- * Context used when hashing a file.
- */
- struct GNUNET_CRYPTO_FileHashContext
- {
- /**
- * Function to call upon completion.
- */
- GNUNET_CRYPTO_HashCompletedCallback callback;
- /**
- * Closure for callback.
- */
- void *callback_cls;
- /**
- * IO buffer.
- */
- unsigned char *buffer;
- /**
- * Name of the file we are hashing.
- */
- char *filename;
- /**
- * File descriptor.
- */
- struct GNUNET_DISK_FileHandle *fh;
- /**
- * Cummulated hash.
- */
- gcry_md_hd_t md;
- /**
- * Size of the file.
- */
- uint64_t fsize;
- /**
- * Current offset.
- */
- uint64_t offset;
- /**
- * Current task for hashing.
- */
- struct GNUNET_SCHEDULER_Task *task;
- /**
- * Priority we use.
- */
- enum GNUNET_SCHEDULER_Priority priority;
- /**
- * Blocksize.
- */
- size_t bsize;
- };
- /**
- * Report result of hash computation to callback
- * and free associated resources.
- */
- static void
- file_hash_finish (struct GNUNET_CRYPTO_FileHashContext *fhc,
- const struct GNUNET_HashCode *res)
- {
- fhc->callback (fhc->callback_cls, res);
- GNUNET_free (fhc->filename);
- if (! GNUNET_DISK_handle_invalid (fhc->fh))
- GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
- gcry_md_close (fhc->md);
- GNUNET_free (fhc); /* also frees fhc->buffer */
- }
- /**
- * File hashing task.
- *
- * @param cls closure
- */
- static void
- file_hash_task (void *cls)
- {
- struct GNUNET_CRYPTO_FileHashContext *fhc = cls;
- struct GNUNET_HashCode *res;
- size_t delta;
- ssize_t sret;
- fhc->task = NULL;
- GNUNET_assert (fhc->offset <= fhc->fsize);
- delta = fhc->bsize;
- if (fhc->fsize - fhc->offset < delta)
- delta = fhc->fsize - fhc->offset;
- sret = GNUNET_DISK_file_read (fhc->fh,
- fhc->buffer,
- delta);
- if ((sret < 0) ||
- (delta != (size_t) sret))
- {
- LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
- "read",
- fhc->filename);
- file_hash_finish (fhc,
- NULL);
- return;
- }
- gcry_md_write (fhc->md,
- fhc->buffer,
- delta);
- fhc->offset += delta;
- if (fhc->offset == fhc->fsize)
- {
- res = (struct GNUNET_HashCode *) gcry_md_read (fhc->md,
- GCRY_MD_SHA512);
- file_hash_finish (fhc, res);
- return;
- }
- fhc->task = GNUNET_SCHEDULER_add_with_priority (fhc->priority,
- &file_hash_task,
- fhc);
- }
- /**
- * Compute the hash of an entire file.
- *
- * @param priority scheduling priority to use
- * @param filename name of file to hash
- * @param blocksize number of bytes to process in one task
- * @param callback function to call upon completion
- * @param callback_cls closure for @a callback
- * @return NULL on (immediate) error
- */
- struct GNUNET_CRYPTO_FileHashContext *
- GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
- const char *filename,
- size_t blocksize,
- GNUNET_CRYPTO_HashCompletedCallback callback,
- void *callback_cls)
- {
- struct GNUNET_CRYPTO_FileHashContext *fhc;
- GNUNET_assert (blocksize > 0);
- fhc =
- GNUNET_malloc (sizeof(struct GNUNET_CRYPTO_FileHashContext) + blocksize);
- fhc->callback = callback;
- fhc->callback_cls = callback_cls;
- fhc->buffer = (unsigned char *) &fhc[1];
- fhc->filename = GNUNET_strdup (filename);
- if (GPG_ERR_NO_ERROR != gcry_md_open (&fhc->md, GCRY_MD_SHA512, 0))
- {
- GNUNET_break (0);
- GNUNET_free (fhc);
- return NULL;
- }
- fhc->bsize = blocksize;
- if (GNUNET_OK !=
- GNUNET_DISK_file_size (filename,
- &fhc->fsize,
- GNUNET_NO,
- GNUNET_YES))
- {
- GNUNET_free (fhc->filename);
- GNUNET_free (fhc);
- return NULL;
- }
- fhc->fh = GNUNET_DISK_file_open (filename,
- GNUNET_DISK_OPEN_READ,
- GNUNET_DISK_PERM_NONE);
- if (! fhc->fh)
- {
- GNUNET_free (fhc->filename);
- GNUNET_free (fhc);
- return NULL;
- }
- fhc->priority = priority;
- fhc->task = GNUNET_SCHEDULER_add_with_priority (priority,
- &file_hash_task,
- fhc);
- return fhc;
- }
- /**
- * Cancel a file hashing operation.
- *
- * @param fhc operation to cancel (callback must not yet have been invoked)
- */
- void
- GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc)
- {
- GNUNET_SCHEDULER_cancel (fhc->task);
- GNUNET_free (fhc->filename);
- GNUNET_break (GNUNET_OK ==
- GNUNET_DISK_file_close (fhc->fh));
- GNUNET_free (fhc);
- }
- /* end of crypto_hash_file.c */
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