librsync  2.3.4
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1/*= -*- c-basic-offset: 4; indent-tabs-mode: nil; -*-
2 *
3 * librsync -- library for network deltas
4 *
5 * Copyright 1999-2001, 2014, 2015 by Martin Pool <>
6 * Copyright (C) 1999 by Andrew Tridgell <>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU Lesser General Public License as published by
10 * the Free Software Foundation; either version 2.1 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * GNU Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
23/** \file mksum.c
24 * Generate file signatures.
25 *
26 * Generating checksums is pretty easy, since we can always just process
27 * whatever data is available. When a whole block has arrived, or we've reached
28 * the end of the file, we write the checksum out. */
30#include "config.h" /* IWYU pragma: keep */
31#include <stdlib.h>
32#include "librsync.h"
33#include "job.h"
34#include "sumset.h"
35#include "scoop.h"
36#include "netint.h"
37#include "trace.h"
38#include "util.h"
40/* Possible state functions for signature generation. */
44/** State of trying to send the signature header. \private */
47 rs_signature_t *sig = job->signature;
48 rs_result result;
50 if ((result =
51 rs_signature_init(sig, job->sig_magic, job->sig_block_len,
52 job->sig_strong_len, 0)) != RS_DONE)
53 return result;
54 rs_squirt_n4(job, sig->magic);
55 rs_squirt_n4(job, sig->block_len);
56 rs_squirt_n4(job, sig->strong_sum_len);
57 rs_trace("sent header (magic %#x, block len = %d, strong sum len = %d)",
58 sig->magic, sig->block_len, sig->strong_sum_len);
59 job->stats.block_len = sig->block_len;
62 return RS_RUNNING;
65/** Generate the checksums for a block and write it out. Called when we
66 * already know we have enough data in memory at \p block. \private */
67static rs_result rs_sig_do_block(rs_job_t *job, const void *block, size_t len)
69 rs_signature_t *sig = job->signature;
70 rs_weak_sum_t weak_sum;
71 rs_strong_sum_t strong_sum;
73 weak_sum = rs_signature_calc_weak_sum(sig, block, len);
74 rs_signature_calc_strong_sum(sig, block, len, &strong_sum);
75 rs_squirt_n4(job, weak_sum);
76 rs_tube_write(job, strong_sum, sig->strong_sum_len);
77 if (rs_trace_enabled()) {
78 char strong_sum_hex[RS_MAX_STRONG_SUM_LENGTH * 2 + 1];
79 rs_hexify(strong_sum_hex, strong_sum, sig->strong_sum_len);
80 rs_trace("sent block: weak=" FMT_WEAKSUM ", strong=%s", weak_sum,
81 strong_sum_hex);
82 }
83 job->stats.sig_blocks++;
84 return RS_RUNNING;
87/** State of reading a block and trying to generate its sum. \private */
90 rs_result result;
91 size_t len;
92 void *block;
94 /* must get a whole block, otherwise try again */
95 len = job->signature->block_len;
96 result = rs_scoop_read(job, len, &block);
97 /* If we are near EOF, get whatever is left. */
98 if (result == RS_INPUT_ENDED)
99 result = rs_scoop_read_rest(job, &len, &block);
100 if (result == RS_INPUT_ENDED) {
101 return RS_DONE;
102 } else if (result != RS_DONE) {
103 rs_trace("generate stopped: %s", rs_strerror(result));
104 return result;
105 }
106 rs_trace("got " FMT_SIZE " byte block", len);
107 return rs_sig_do_block(job, block, len);
110rs_job_t *rs_sig_begin(size_t block_len, size_t strong_len,
111 rs_magic_number sig_magic)
113 rs_job_t *job;
115 job = rs_job_new("signature", rs_sig_s_header);
117 job->job_owns_sig = 1;
118 job->sig_magic = sig_magic;
119 job->sig_block_len = (int)block_len;
120 job->sig_strong_len = (int)strong_len;
121 return job;
Generic state-machine interface.
Public header for librsync.
LIBRSYNC_EXPORT char const * rs_strerror(rs_result r)
Return an English description of a rs_result value.
Definition: msg.c:46
Return codes from nonblocking rsync operations.
Definition: librsync.h:180
The job is still running, and not yet finished or blocked.
Definition: librsync.h:183
Completed successfully.
Definition: librsync.h:181
Unexpected end of input file, perhaps due to a truncated file or dropped network connection.
Definition: librsync.h:190
A uint32 magic number, emitted in bigendian/network order at the start of librsync files.
Definition: librsync.h:65
LIBRSYNC_EXPORT void rs_hexify(char *to_buf, void const *from_buf, int from_len)
Convert from_len bytes at from_buf into a hex representation in to_buf, which must be twice as long p...
Definition: hex.c:23
rs_job_t * rs_sig_begin(size_t block_len, size_t strong_len, rs_magic_number sig_magic)
Start generating a signature.
Definition: mksum.c:110
static rs_result rs_sig_s_generate(rs_job_t *)
State of reading a block and trying to generate its sum.
Definition: mksum.c:88
static rs_result rs_sig_s_header(rs_job_t *)
State of trying to send the signature header.
Definition: mksum.c:45
Network-byte-order output to the tube.
rs_result rs_scoop_read(rs_job_t *job, size_t len, void **ptr)
Read LEN bytes if possible, and remove them from the input scoop.
Definition: scoop.c:192
rs_result rs_scoop_read_rest(rs_job_t *job, size_t *len, void **ptr)
Read whatever data remains in the input stream.
Definition: scoop.c:212
Manage librsync streams of IO.
void rs_tube_write(rs_job_t *job, void const *buf, size_t len)
Push some data into the tube for storage.
Definition: tube.c:174
The contents of this structure are private.
Definition: job.h:47
int job_owns_sig
Flag indicating signature should be destroyed with the job.
Definition: job.h:75
rs_result(* statefn)(rs_job_t *)
Callback for each processing step.
Definition: job.h:56
rs_signature_t * signature
Pointer to the signature that's being used by the operation.
Definition: job.h:72
rs_stats_t stats
Encoding statistics.
Definition: job.h:93
Signature of a whole file.
Definition: sumset.h:44
int magic
The signature magic value.
Definition: sumset.h:45
int block_len
The block length.
Definition: sumset.h:46
int strong_sum_len
The block strong sum length.
Definition: sumset.h:47
rs_long_t sig_blocks
Number of blocks described by the signature.
Definition: librsync.h:222
The rs_signature class implementation of a file signature.
static rs_weak_sum_t rs_signature_calc_weak_sum(rs_signature_t const *sig, void const *buf, size_t len)
Calculate the weak sum of a buffer.
Definition: sumset.h:128
static void rs_signature_calc_strong_sum(rs_signature_t const *sig, void const *buf, size_t len, rs_strong_sum_t *sum)
Calculate the strong sum of a buffer.
Definition: sumset.h:136
rs_result rs_signature_init(rs_signature_t *sig, rs_magic_number magic, size_t block_len, size_t strong_len, rs_long_t sig_fsize)
Initialize an rs_signature instance.
Definition: sumset.c:183
logging functions.
#define rs_trace_enabled()
Call this before putting too much effort into generating trace messages.
Definition: trace.h:70
Misc utility functions used by librsync.
#define rs_alloc_struct(type)
Allocate and zero-fill an instance of TYPE.
Definition: util.h:41