librsync  2.3.2
patch.c
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#include "config.h"
27#include <assert.h>
28#include <stdlib.h>
29#include <string.h>
30#include "librsync.h"
31#include "job.h"
32#include "netint.h"
33#include "stream.h"
34#include "command.h"
35#include "prototab.h"
36#include "trace.h"
37
38static rs_result rs_patch_s_cmdbyte(rs_job_t *);
39static rs_result rs_patch_s_params(rs_job_t *);
40static rs_result rs_patch_s_run(rs_job_t *);
41static rs_result rs_patch_s_literal(rs_job_t *);
42static rs_result rs_patch_s_copy(rs_job_t *);
43static rs_result rs_patch_s_copying(rs_job_t *);
44
45/** State of trying to read the first byte of a command. Once we've taken that
46 * in, we can know how much data to read to get the arguments. */
47static rs_result rs_patch_s_cmdbyte(rs_job_t *job)
48{
49 rs_result result;
50
51 if ((result = rs_suck_byte(job, &job->op)) != RS_DONE)
52 return result;
53 job->cmd = &rs_prototab[job->op];
54 rs_trace("got command %#04x (%s), len_1=%d, len_2=%d", job->op,
55 rs_op_kind_name(job->cmd->kind), job->cmd->len_1, job->cmd->len_2);
56 if (job->cmd->len_1)
57 job->statefn = rs_patch_s_params;
58 else {
59 job->param1 = job->cmd->immediate;
60 job->statefn = rs_patch_s_run;
61 }
62 return RS_RUNNING;
63}
64
65/** Called after reading a command byte to pull in its parameters and then
66 * setup to execute the command. */
67static rs_result rs_patch_s_params(rs_job_t *job)
68{
69 rs_result result;
70 const size_t len = (size_t)(job->cmd->len_1 + job->cmd->len_2);
71 void *p;
72
73 assert(len);
74 result = rs_scoop_readahead(job, len, &p);
75 if (result != RS_DONE)
76 return result;
77 /* we now must have LEN bytes buffered */
78 result = rs_suck_netint(job, &job->param1, job->cmd->len_1);
79 /* shouldn't fail, since we already checked */
80 assert(result == RS_DONE);
81 if (job->cmd->len_2) {
82 result = rs_suck_netint(job, &job->param2, job->cmd->len_2);
83 assert(result == RS_DONE);
84 }
85 job->statefn = rs_patch_s_run;
86 return RS_RUNNING;
87}
88
89/** Called when we've read in the whole command and we need to execute it. */
90static rs_result rs_patch_s_run(rs_job_t *job)
91{
92 rs_trace("running command %#04x", job->op);
93 switch (job->cmd->kind) {
94 case RS_KIND_LITERAL:
95 job->statefn = rs_patch_s_literal;
96 return RS_RUNNING;
97 case RS_KIND_END:
98 return RS_DONE;
99 /* so we exit here; trying to continue causes an error */
100 case RS_KIND_COPY:
101 job->statefn = rs_patch_s_copy;
102 return RS_RUNNING;
103 default:
104 rs_error("bogus command %#04x", job->op);
105 return RS_CORRUPT;
106 }
107}
108
109/** Called when trying to copy through literal data. */
110static rs_result rs_patch_s_literal(rs_job_t *job)
111{
112 const rs_long_t len = job->param1;
113 rs_stats_t *stats = &job->stats;
114
115 rs_trace("LITERAL(length=" FMT_LONG ")", len);
116 if (len <= 0 || len > SIZE_MAX) {
117 rs_error("invalid length=" FMT_LONG " on LITERAL command", len);
118 return RS_CORRUPT;
119 }
120 stats->lit_cmds++;
121 stats->lit_bytes += len;
122 stats->lit_cmdbytes += 1 + job->cmd->len_1;
123 rs_tube_copy(job, (size_t)len);
124 job->statefn = rs_patch_s_cmdbyte;
125 return RS_RUNNING;
126}
127
128static rs_result rs_patch_s_copy(rs_job_t *job)
129{
130 const rs_long_t pos = job->param1;
131 const rs_long_t len = job->param2;
132 rs_stats_t *stats = &job->stats;
133
134 rs_trace("COPY(position=" FMT_LONG ", length=" FMT_LONG ")", pos, len);
135 if (len <= 0) {
136 rs_error("invalid length=" FMT_LONG " on COPY command", len);
137 return RS_CORRUPT;
138 }
139 if (pos < 0) {
140 rs_error("invalid position=" FMT_LONG " on COPY command", pos);
141 return RS_CORRUPT;
142 }
143 stats->copy_cmds++;
144 stats->copy_bytes += len;
145 stats->copy_cmdbytes += 1 + job->cmd->len_1 + job->cmd->len_2;
146 job->basis_pos = pos;
147 job->basis_len = len;
148 job->statefn = rs_patch_s_copying;
149 return RS_RUNNING;
150}
151
152/** Called when we're executing a COPY command and waiting for all the data to
153 * be retrieved from the callback. */
154static rs_result rs_patch_s_copying(rs_job_t *job)
155{
156 rs_result result;
157 rs_buffers_t *buffs = job->stream;
158 rs_long_t req = job->basis_len;
159 size_t len = buffs->avail_out;
160 void *ptr = buffs->next_out;
161
162 /* We are blocked if there is no space left to copy into. */
163 if (!len)
164 return RS_BLOCKED;
165 /* Adjust request to min of amount requested and space available. */
166 if (len < req)
167 req = (rs_long_t)len;
168 rs_trace("copy " FMT_LONG " bytes from basis at offset " FMT_LONG "", req,
169 job->basis_pos);
170 len = (size_t)req;
171 result = (job->copy_cb) (job->copy_arg, job->basis_pos, &len, &ptr);
172 if (result != RS_DONE) {
173 rs_trace("copy callback returned %s", rs_strerror(result));
174 return result;
175 }
176 rs_trace("got " FMT_SIZE " bytes back from basis callback", len);
177 /* Actual copied length cannot be greater than requested length. */
178 assert(len <= req);
179 /* Backwards-compatible defensively handle this for NDEBUG builds. */
180 if (len > req) {
181 rs_warn("copy_cb() returned more than the requested length");
182 len = (size_t)req;
183 }
184 /* copy back to out buffer only if the callback has used its own buffer */
185 if (ptr != buffs->next_out)
186 memcpy(buffs->next_out, ptr, len);
187 /* Update buffs and copy for copied data. */
188 buffs->next_out += len;
189 buffs->avail_out -= len;
190 job->basis_pos += (rs_long_t)len;
191 job->basis_len -= (rs_long_t)len;
192 if (!job->basis_len) {
193 /* Nothing left to copy, we are done! */
194 job->statefn = rs_patch_s_cmdbyte;
195 }
196 return RS_RUNNING;
197}
198
199/** Called while we're trying to read the header of the patch. */
200static rs_result rs_patch_s_header(rs_job_t *job)
201{
202 int v;
203 rs_result result;
204
205 if ((result = rs_suck_n4(job, &v)) != RS_DONE)
206 return result;
207 if (v != RS_DELTA_MAGIC) {
208 rs_error("got magic number %#x rather than expected value %#x", v,
210 return RS_BAD_MAGIC;
211 } else
212 rs_trace("got patch magic %#x", v);
213 job->statefn = rs_patch_s_cmdbyte;
214 return RS_RUNNING;
215}
216
217rs_job_t *rs_patch_begin(rs_copy_cb * copy_cb, void *copy_arg)
218{
219 rs_job_t *job = rs_job_new("patch", rs_patch_s_header);
220
221 job->copy_cb = copy_cb;
222 job->copy_arg = copy_arg;
223 rs_mdfour_begin(&job->output_md4);
224 return job;
225}
Types of commands present in the encoding stream.
Public header for librsync.
LIBRSYNC_EXPORT 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:217
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:493
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:200
Description of input and output buffers.
Definition: librsync.h:322
size_t avail_out
Remaining free space at next_out.
Definition: librsync.h:351
char * next_out
Next output byte should be put there.
Definition: librsync.h:345
The contents of this structure are private.
Definition: job.h:26
rs_long_t basis_pos
Copy from the basis position.
Definition: job.h:92
unsigned char op
Command byte currently being processed, if any.
Definition: job.h:57
rs_copy_cb * copy_cb
Callback used to copy data from the basis into the output.
Definition: job.h:95
rs_result(* statefn)(rs_job_t *)
Callback for each processing step.
Definition: job.h:35
rs_stats_t stats
Encoding statistics.
Definition: job.h:72
rs_long_t param1
Lengths of expected parameters.
Definition: job.h:66
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.