librsync  2.3.4
patch.c
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1/*= -*- c-basic-offset: 4; indent-tabs-mode: nil; -*-
2 *
3 * librsync -- the library for network deltas
4 *
5 * Copyright (C) 2000, 2001 by Martin Pool <mbp@sourcefrog.net>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public License
9 * as published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22 /*=
23 | This is Tranquility Base.
24 */
25
26/** \file patch.c
27 * Apply a delta to an old file to generate a new file. */
28
29#include "config.h" /* IWYU pragma: keep */
30#include <assert.h>
31#include <stdlib.h>
32#include <string.h>
33#include <stdint.h>
34#include "librsync.h"
35#include "job.h"
36#include "netint.h"
37#include "scoop.h"
38#include "command.h"
39#include "prototab.h"
40#include "trace.h"
41
46static rs_result rs_patch_s_copy(rs_job_t *);
48
49/** State of trying to read the first byte of a command. Once we've taken that
50 * in, we can know how much data to read to get the arguments. */
52{
53 rs_result result;
54
55 if ((result = rs_suck_byte(job, &job->op)) != RS_DONE)
56 return result;
57 job->cmd = &rs_prototab[job->op];
58 rs_trace("got command %#04x (%s), len_1=%d, len_2=%d", job->op,
59 rs_op_kind_name(job->cmd->kind), job->cmd->len_1, job->cmd->len_2);
60 if (job->cmd->len_1)
62 else {
63 job->param1 = job->cmd->immediate;
65 }
66 return RS_RUNNING;
67}
68
69/** Called after reading a command byte to pull in its parameters and then
70 * setup to execute the command. */
72{
73 rs_result result;
74 const size_t len = (size_t)(job->cmd->len_1 + job->cmd->len_2);
75 void *p;
76
77 assert(len);
78 result = rs_scoop_readahead(job, len, &p);
79 if (result != RS_DONE)
80 return result;
81 /* we now must have LEN bytes buffered */
82 result = rs_suck_netint(job, &job->param1, job->cmd->len_1);
83 /* shouldn't fail, since we already checked */
84 assert(result == RS_DONE);
85 if (job->cmd->len_2) {
86 result = rs_suck_netint(job, &job->param2, job->cmd->len_2);
87 assert(result == RS_DONE);
88 }
90 return RS_RUNNING;
91}
92
93/** Called when we've read in the whole command and we need to execute it. */
95{
96 rs_trace("running command %#04x", job->op);
97 switch (job->cmd->kind) {
98 case RS_KIND_LITERAL:
100 return RS_RUNNING;
101 case RS_KIND_END:
102 return RS_DONE;
103 /* so we exit here; trying to continue causes an error */
104 case RS_KIND_COPY:
105 job->statefn = rs_patch_s_copy;
106 return RS_RUNNING;
107 default:
108 rs_error("bogus command %#04x", job->op);
109 return RS_CORRUPT;
110 }
111}
112
113/** Called when trying to copy through literal data. */
115{
116 const rs_long_t len = job->param1;
117 rs_stats_t *stats = &job->stats;
118
119 rs_trace("LITERAL(length=" FMT_LONG ")", len);
120 if (len <= 0 || len > SIZE_MAX) {
121 rs_error("invalid length=" FMT_LONG " on LITERAL command", len);
122 return RS_CORRUPT;
123 }
124 stats->lit_cmds++;
125 stats->lit_bytes += len;
126 stats->lit_cmdbytes += 1 + job->cmd->len_1;
127 rs_tube_copy(job, (size_t)len);
129 return RS_RUNNING;
130}
131
132static rs_result rs_patch_s_copy(rs_job_t *job)
133{
134 const rs_long_t pos = job->param1;
135 const rs_long_t len = job->param2;
136 rs_stats_t *stats = &job->stats;
137
138 rs_trace("COPY(position=" FMT_LONG ", length=" FMT_LONG ")", pos, len);
139 if (len <= 0) {
140 rs_error("invalid length=" FMT_LONG " on COPY command", len);
141 return RS_CORRUPT;
142 }
143 if (pos < 0) {
144 rs_error("invalid position=" FMT_LONG " on COPY command", pos);
145 return RS_CORRUPT;
146 }
147 stats->copy_cmds++;
148 stats->copy_bytes += len;
149 stats->copy_cmdbytes += 1 + job->cmd->len_1 + job->cmd->len_2;
150 job->basis_pos = pos;
151 job->basis_len = len;
153 return RS_RUNNING;
154}
155
156/** Called when we're executing a COPY command and waiting for all the data to
157 * be retrieved from the callback. */
159{
160 rs_result result;
161 rs_buffers_t *buffs = job->stream;
162 rs_long_t req = job->basis_len;
163 size_t len = buffs->avail_out;
164 void *ptr = buffs->next_out;
165
166 /* We are blocked if there is no space left to copy into. */
167 if (!len)
168 return RS_BLOCKED;
169 /* Adjust request to min of amount requested and space available. */
170 if ((rs_long_t)len < req)
171 req = (rs_long_t)len;
172 rs_trace("copy " FMT_LONG " bytes from basis at offset " FMT_LONG "", req,
173 job->basis_pos);
174 len = (size_t)req;
175 result = (job->copy_cb) (job->copy_arg, job->basis_pos, &len, &ptr);
176 if (result != RS_DONE) {
177 rs_trace("copy callback returned %s", rs_strerror(result));
178 return result;
179 }
180 rs_trace("got " FMT_SIZE " bytes back from basis callback", len);
181 /* Actual copied length cannot be greater than requested length. */
182 assert(len <= req);
183 /* Backwards-compatible defensively handle this for NDEBUG builds. */
184 if ((rs_long_t)len > req) {
185 rs_warn("copy_cb() returned more than the requested length");
186 len = (size_t)req;
187 }
188 /* copy back to out buffer only if the callback has used its own buffer */
189 if (ptr != buffs->next_out)
190 memcpy(buffs->next_out, ptr, len);
191 /* Update buffs and copy for copied data. */
192 buffs->next_out += len;
193 buffs->avail_out -= len;
194 job->basis_pos += (rs_long_t)len;
195 job->basis_len -= (rs_long_t)len;
196 if (!job->basis_len) {
197 /* Nothing left to copy, we are done! */
199 }
200 return RS_RUNNING;
201}
202
203/** Called while we're trying to read the header of the patch. */
205{
206 int v;
207 rs_result result;
208
209 if ((result = rs_suck_n4(job, &v)) != RS_DONE)
210 return result;
211 if (v != RS_DELTA_MAGIC) {
212 rs_error("got magic number %#x rather than expected value %#x", v,
214 return RS_BAD_MAGIC;
215 } else
216 rs_trace("got patch magic %#x", v);
218 return RS_RUNNING;
219}
220
221rs_job_t *rs_patch_begin(rs_copy_cb * copy_cb, void *copy_arg)
222{
223 rs_job_t *job = rs_job_new("patch", rs_patch_s_header);
224
225 job->copy_cb = copy_cb;
226 job->copy_arg = copy_arg;
227 rs_mdfour_begin(&job->output_md4);
228 return job;
229}
Types of commands present in the encoding stream.
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
rs_result
Return codes from nonblocking rsync operations.
Definition: librsync.h:180
@ RS_RUNNING
The job is still running, and not yet finished or blocked.
Definition: librsync.h:183
@ RS_DONE
Completed successfully.
Definition: librsync.h:181
@ RS_CORRUPT
Unbelievable value in stream.
Definition: librsync.h:198
@ RS_BAD_MAGIC
Bad magic number at start of stream.
Definition: librsync.h:193
@ RS_BLOCKED
Blocked waiting for more data.
Definition: librsync.h:182
@ RS_DELTA_MAGIC
A delta file.
Definition: librsync.h:71
rs_result rs_copy_cb(void *opaque, rs_long_t pos, size_t *len, void **buf)
Callback used to retrieve parts of the basis file.
Definition: librsync.h:502
Network-byte-order output to the tube.
static rs_result rs_patch_s_literal(rs_job_t *)
Called when trying to copy through literal data.
Definition: patch.c:114
static rs_result rs_patch_s_params(rs_job_t *)
Called after reading a command byte to pull in its parameters and then setup to execute the command.
Definition: patch.c:71
static rs_result rs_patch_s_cmdbyte(rs_job_t *)
State of trying to read the first byte of a command.
Definition: patch.c:51
static rs_result rs_patch_s_copying(rs_job_t *)
Called when we're executing a COPY command and waiting for all the data to be retrieved from the call...
Definition: patch.c:158
static rs_result rs_patch_s_header(rs_job_t *job)
Called while we're trying to read the header of the patch.
Definition: patch.c:204
static rs_result rs_patch_s_run(rs_job_t *)
Called when we've read in the whole command and we need to execute it.
Definition: patch.c:94
rs_job_t * rs_patch_begin(rs_copy_cb *copy_cb, void *copy_arg)
Apply a delta to a basis file to recreate the new file.
Definition: patch.c:221
Delta file commands.
rs_result rs_scoop_readahead(rs_job_t *job, size_t len, void **ptr)
Read from scoop without advancing.
Definition: scoop.c:148
Manage librsync streams of IO.
void rs_tube_copy(rs_job_t *job, size_t len)
Queue up a request to copy through len bytes from the input to the output of the stream.
Definition: tube.c:160
Description of input and output buffers.
Definition: librsync.h:328
size_t avail_out
Remaining free space at next_out.
Definition: librsync.h:357
char * next_out
Next output byte should be put there.
Definition: librsync.h:351
The contents of this structure are private.
Definition: job.h:47
rs_long_t basis_pos
Copy from the basis position.
Definition: job.h:117
unsigned char op
Command byte currently being processed, if any.
Definition: job.h:78
rs_copy_cb * copy_cb
Callback used to copy data from the basis into the output.
Definition: job.h:120
rs_result(* statefn)(rs_job_t *)
Callback for each processing step.
Definition: job.h:56
rs_stats_t stats
Encoding statistics.
Definition: job.h:93
rs_long_t param1
Lengths of expected parameters.
Definition: job.h:87
Performance statistics from a librsync encoding or decoding operation.
Definition: librsync.h:210
int lit_cmds
Number of literal commands.
Definition: librsync.h:213
rs_long_t lit_cmdbytes
Number of bytes used in literal command headers.
Definition: librsync.h:215
rs_long_t lit_bytes
Number of literal bytes.
Definition: librsync.h:214
logging functions.