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1 | // -*- mode: cpp; mode: fold -*- | |
2 | // Description /*{{{*/ | |
3 | // $Id: multicompress.cc,v 1.4 2003/02/10 07:34:41 doogie Exp $ | |
4 | /* ###################################################################### | |
5 | ||
6 | MultiCompressor | |
7 | ||
8 | This class is very complicated in order to optimize for the common | |
9 | case of its use, writing a large set of compressed files that are | |
10 | different from the old set. It spawns off compressors in parallel | |
11 | to maximize compression throughput and has a separate task managing | |
12 | the data going into the compressors. | |
13 | ||
14 | ##################################################################### */ | |
15 | /*}}}*/ | |
16 | // Include Files /*{{{*/ | |
17 | #include <config.h> | |
18 | ||
19 | #include <apt-pkg/fileutl.h> | |
20 | #include <apt-pkg/strutl.h> | |
21 | #include <apt-pkg/error.h> | |
22 | #include <apt-pkg/md5.h> | |
23 | ||
24 | #include <sys/types.h> | |
25 | #include <sys/stat.h> | |
26 | #include <utime.h> | |
27 | #include <unistd.h> | |
28 | #include <iostream> | |
29 | ||
30 | #include "multicompress.h" | |
31 | #include <apti18n.h> | |
32 | /*}}}*/ | |
33 | ||
34 | using namespace std; | |
35 | ||
36 | ||
37 | // MultiCompress::MultiCompress - Constructor /*{{{*/ | |
38 | // --------------------------------------------------------------------- | |
39 | /* Setup the file outputs, compression modes and fork the writer child */ | |
40 | MultiCompress::MultiCompress(string const &Output,string const &Compress, | |
41 | mode_t const &Permissions,bool const &Write) : | |
42 | Permissions(Permissions) | |
43 | { | |
44 | Outputs = 0; | |
45 | Outputter = -1; | |
46 | Input = 0; | |
47 | UpdateMTime = 0; | |
48 | ||
49 | /* Parse the compression string, a space separated lists of compresison | |
50 | types */ | |
51 | string::const_iterator I = Compress.begin(); | |
52 | for (; I != Compress.end();) | |
53 | { | |
54 | for (; I != Compress.end() && isspace(*I); ++I); | |
55 | ||
56 | // Grab a word | |
57 | string::const_iterator Start = I; | |
58 | for (; I != Compress.end() && !isspace(*I); ++I); | |
59 | ||
60 | // Find the matching compressor | |
61 | std::vector<APT::Configuration::Compressor> Compressors = APT::Configuration::getCompressors(); | |
62 | std::vector<APT::Configuration::Compressor>::const_iterator Comp = Compressors.begin(); | |
63 | for (; Comp != Compressors.end(); ++Comp) | |
64 | if (stringcmp(Start,I,Comp->Name.c_str()) == 0) | |
65 | break; | |
66 | ||
67 | // Hmm.. unknown. | |
68 | if (Comp == Compressors.end()) | |
69 | { | |
70 | _error->Warning(_("Unknown compression algorithm '%s'"),string(Start,I).c_str()); | |
71 | continue; | |
72 | } | |
73 | ||
74 | // Create and link in a new output | |
75 | Files *NewOut = new Files; | |
76 | NewOut->Next = Outputs; | |
77 | Outputs = NewOut; | |
78 | NewOut->CompressProg = *Comp; | |
79 | NewOut->Output = Output+Comp->Extension; | |
80 | ||
81 | struct stat St; | |
82 | if (stat(NewOut->Output.c_str(),&St) == 0) | |
83 | NewOut->OldMTime = St.st_mtime; | |
84 | else | |
85 | NewOut->OldMTime = 0; | |
86 | } | |
87 | ||
88 | if (Write == false) | |
89 | return; | |
90 | ||
91 | /* Open all the temp files now so we can report any errors. File is | |
92 | made unreable to prevent people from touching it during creating. */ | |
93 | for (Files *I = Outputs; I != 0; I = I->Next) | |
94 | I->TmpFile.Open(I->Output + ".new", FileFd::WriteOnly | FileFd::Create | FileFd::Empty, FileFd::Extension, 0600); | |
95 | if (_error->PendingError() == true) | |
96 | return; | |
97 | ||
98 | if (Outputs == 0) | |
99 | { | |
100 | _error->Error(_("Compressed output %s needs a compression set"),Output.c_str()); | |
101 | return; | |
102 | } | |
103 | ||
104 | Start(); | |
105 | } | |
106 | /*}}}*/ | |
107 | // MultiCompress::~MultiCompress - Destructor /*{{{*/ | |
108 | // --------------------------------------------------------------------- | |
109 | /* Just erase the file linked list. */ | |
110 | MultiCompress::~MultiCompress() | |
111 | { | |
112 | Die(); | |
113 | ||
114 | for (; Outputs != 0;) | |
115 | { | |
116 | Files *Tmp = Outputs->Next; | |
117 | delete Outputs; | |
118 | Outputs = Tmp; | |
119 | } | |
120 | } | |
121 | /*}}}*/ | |
122 | // MultiCompress::GetStat - Get stat information for compressed files /*{{{*/ | |
123 | // --------------------------------------------------------------------- | |
124 | /* This checks each compressed file to make sure it exists and returns | |
125 | stat information for a random file from the collection. False means | |
126 | one or more of the files is missing. */ | |
127 | bool MultiCompress::GetStat(string const &Output,string const &Compress,struct stat &St) | |
128 | { | |
129 | /* Parse the compression string, a space separated lists of compresison | |
130 | types */ | |
131 | string::const_iterator I = Compress.begin(); | |
132 | bool DidStat = false; | |
133 | for (; I != Compress.end();) | |
134 | { | |
135 | for (; I != Compress.end() && isspace(*I); ++I); | |
136 | ||
137 | // Grab a word | |
138 | string::const_iterator Start = I; | |
139 | for (; I != Compress.end() && !isspace(*I); ++I); | |
140 | ||
141 | // Find the matching compressor | |
142 | std::vector<APT::Configuration::Compressor> Compressors = APT::Configuration::getCompressors(); | |
143 | std::vector<APT::Configuration::Compressor>::const_iterator Comp = Compressors.begin(); | |
144 | for (; Comp != Compressors.end(); ++Comp) | |
145 | if (stringcmp(Start,I,Comp->Name.c_str()) == 0) | |
146 | break; | |
147 | ||
148 | // Hmm.. unknown. | |
149 | if (Comp == Compressors.end()) | |
150 | continue; | |
151 | ||
152 | string Name = Output+Comp->Extension; | |
153 | if (stat(Name.c_str(),&St) != 0) | |
154 | return false; | |
155 | DidStat = true; | |
156 | } | |
157 | return DidStat; | |
158 | } | |
159 | /*}}}*/ | |
160 | // MultiCompress::Start - Start up the writer child /*{{{*/ | |
161 | // --------------------------------------------------------------------- | |
162 | /* Fork a child and setup the communication pipe. */ | |
163 | bool MultiCompress::Start() | |
164 | { | |
165 | // Create a data pipe | |
166 | int Pipe[2] = {-1,-1}; | |
167 | if (pipe(Pipe) != 0) | |
168 | return _error->Errno("pipe",_("Failed to create IPC pipe to subprocess")); | |
169 | for (int I = 0; I != 2; I++) | |
170 | SetCloseExec(Pipe[I],true); | |
171 | ||
172 | // The child.. | |
173 | Outputter = fork(); | |
174 | if (Outputter == 0) | |
175 | { | |
176 | close(Pipe[1]); | |
177 | Child(Pipe[0]); | |
178 | if (_error->PendingError() == true) | |
179 | { | |
180 | _error->DumpErrors(); | |
181 | _exit(100); | |
182 | } | |
183 | _exit(0); | |
184 | }; | |
185 | ||
186 | close(Pipe[0]); | |
187 | Input = fdopen(Pipe[1],"w"); | |
188 | if (Input == 0) | |
189 | return _error->Errno("fdopen",_("Failed to create FILE*")); | |
190 | ||
191 | if (Outputter == -1) | |
192 | return _error->Errno("fork",_("Failed to fork")); | |
193 | return true; | |
194 | } | |
195 | /*}}}*/ | |
196 | // MultiCompress::Die - Clean up the writer /*{{{*/ | |
197 | // --------------------------------------------------------------------- | |
198 | /* */ | |
199 | bool MultiCompress::Die() | |
200 | { | |
201 | if (Input == 0) | |
202 | return true; | |
203 | ||
204 | fclose(Input); | |
205 | Input = 0; | |
206 | bool Res = ExecWait(Outputter,_("Compress child"),false); | |
207 | Outputter = -1; | |
208 | return Res; | |
209 | } | |
210 | /*}}}*/ | |
211 | // MultiCompress::Finalize - Finish up writing /*{{{*/ | |
212 | // --------------------------------------------------------------------- | |
213 | /* This is only necessary for statistics reporting. */ | |
214 | bool MultiCompress::Finalize(unsigned long long &OutSize) | |
215 | { | |
216 | OutSize = 0; | |
217 | if (Input == 0 || Die() == false) | |
218 | return false; | |
219 | ||
220 | time_t Now; | |
221 | time(&Now); | |
222 | ||
223 | // Check the mtimes to see if the files were replaced. | |
224 | bool Changed = false; | |
225 | for (Files *I = Outputs; I != 0; I = I->Next) | |
226 | { | |
227 | struct stat St; | |
228 | if (stat(I->Output.c_str(),&St) != 0) | |
229 | return _error->Error(_("Internal error, failed to create %s"), | |
230 | I->Output.c_str()); | |
231 | ||
232 | if (I->OldMTime != St.st_mtime) | |
233 | Changed = true; | |
234 | else | |
235 | { | |
236 | // Update the mtime if necessary | |
237 | if (UpdateMTime > 0 && | |
238 | (Now - St.st_mtime > (signed)UpdateMTime || St.st_mtime > Now)) | |
239 | { | |
240 | struct utimbuf Buf; | |
241 | Buf.actime = Buf.modtime = Now; | |
242 | utime(I->Output.c_str(),&Buf); | |
243 | Changed = true; | |
244 | } | |
245 | } | |
246 | ||
247 | // Force the file permissions | |
248 | if (St.st_mode != Permissions) | |
249 | chmod(I->Output.c_str(),Permissions); | |
250 | ||
251 | OutSize += St.st_size; | |
252 | } | |
253 | ||
254 | if (Changed == false) | |
255 | OutSize = 0; | |
256 | ||
257 | return true; | |
258 | } | |
259 | /*}}}*/ | |
260 | // MultiCompress::OpenOld - Open an old file /*{{{*/ | |
261 | // --------------------------------------------------------------------- | |
262 | /* This opens one of the original output files, possibly decompressing it. */ | |
263 | bool MultiCompress::OpenOld(int &Fd,pid_t &Proc) | |
264 | { | |
265 | Files *Best = Outputs; | |
266 | for (Files *I = Outputs; I != 0; I = I->Next) | |
267 | if (Best->CompressProg.Cost > I->CompressProg.Cost) | |
268 | Best = I; | |
269 | ||
270 | // Open the file | |
271 | FileFd F(Best->Output,FileFd::ReadOnly); | |
272 | if (_error->PendingError() == true) | |
273 | return false; | |
274 | ||
275 | // Decompress the file so we can read it | |
276 | if (ExecCompressor(Best->CompressProg,&Proc,F.Fd(),Fd,false) == false) | |
277 | return false; | |
278 | ||
279 | return true; | |
280 | } | |
281 | /*}}}*/ | |
282 | // MultiCompress::CloseOld - Close the old file /*{{{*/ | |
283 | // --------------------------------------------------------------------- | |
284 | /* */ | |
285 | bool MultiCompress::CloseOld(int Fd,pid_t Proc) | |
286 | { | |
287 | close(Fd); | |
288 | if (Proc != -1) | |
289 | if (ExecWait(Proc,_("decompressor"),false) == false) | |
290 | return false; | |
291 | return true; | |
292 | } | |
293 | /*}}}*/ | |
294 | // MultiCompress::Child - The writer child /*{{{*/ | |
295 | // --------------------------------------------------------------------- | |
296 | /* The child process forks a bunch of compression children and takes | |
297 | input on FD and passes it to all the compressor child. On the way it | |
298 | computes the MD5 of the raw data. After this the raw data in the | |
299 | original files is compared to see if this data is new. If the data | |
300 | is new then the temp files are renamed, otherwise they are erased. */ | |
301 | bool MultiCompress::Child(int const &FD) | |
302 | { | |
303 | /* Okay, now we just feed data from FD to all the other FDs. Also | |
304 | stash a hash of the data to use later. */ | |
305 | SetNonBlock(FD,false); | |
306 | unsigned char Buffer[32*1024]; | |
307 | unsigned long long FileSize = 0; | |
308 | MD5Summation MD5; | |
309 | while (1) | |
310 | { | |
311 | WaitFd(FD,false); | |
312 | int Res = read(FD,Buffer,sizeof(Buffer)); | |
313 | if (Res == 0) | |
314 | break; | |
315 | if (Res < 0) | |
316 | continue; | |
317 | ||
318 | MD5.Add(Buffer,Res); | |
319 | FileSize += Res; | |
320 | for (Files *I = Outputs; I != 0; I = I->Next) | |
321 | { | |
322 | if (I->TmpFile.Write(Buffer, Res) == false) | |
323 | { | |
324 | _error->Errno("write",_("IO to subprocess/file failed")); | |
325 | break; | |
326 | } | |
327 | } | |
328 | } | |
329 | ||
330 | if (_error->PendingError() == true) | |
331 | return false; | |
332 | ||
333 | /* Now we have to copy the files over, or erase them if they | |
334 | have not changed. First find the cheapest decompressor */ | |
335 | bool Missing = false; | |
336 | for (Files *I = Outputs; I != 0; I = I->Next) | |
337 | { | |
338 | if (I->OldMTime == 0) | |
339 | { | |
340 | Missing = true; | |
341 | break; | |
342 | } | |
343 | } | |
344 | ||
345 | // Check the MD5 of the lowest cost entity. | |
346 | while (Missing == false) | |
347 | { | |
348 | int CompFd = -1; | |
349 | pid_t Proc = -1; | |
350 | if (OpenOld(CompFd,Proc) == false) | |
351 | { | |
352 | _error->Discard(); | |
353 | break; | |
354 | } | |
355 | ||
356 | // Compute the hash | |
357 | MD5Summation OldMD5; | |
358 | unsigned long long NewFileSize = 0; | |
359 | while (1) | |
360 | { | |
361 | int Res = read(CompFd,Buffer,sizeof(Buffer)); | |
362 | if (Res == 0) | |
363 | break; | |
364 | if (Res < 0) | |
365 | return _error->Errno("read",_("Failed to read while computing MD5")); | |
366 | NewFileSize += Res; | |
367 | OldMD5.Add(Buffer,Res); | |
368 | } | |
369 | ||
370 | // Tidy the compressor | |
371 | if (CloseOld(CompFd,Proc) == false) | |
372 | return false; | |
373 | ||
374 | // Check the hash | |
375 | if (OldMD5.Result() == MD5.Result() && | |
376 | FileSize == NewFileSize) | |
377 | { | |
378 | for (Files *I = Outputs; I != 0; I = I->Next) | |
379 | { | |
380 | I->TmpFile.Close(); | |
381 | if (unlink(I->TmpFile.Name().c_str()) != 0) | |
382 | _error->Errno("unlink",_("Problem unlinking %s"), | |
383 | I->TmpFile.Name().c_str()); | |
384 | } | |
385 | return !_error->PendingError(); | |
386 | } | |
387 | break; | |
388 | } | |
389 | ||
390 | // Finalize | |
391 | for (Files *I = Outputs; I != 0; I = I->Next) | |
392 | { | |
393 | // Set the correct file modes | |
394 | fchmod(I->TmpFile.Fd(),Permissions); | |
395 | ||
396 | if (rename(I->TmpFile.Name().c_str(),I->Output.c_str()) != 0) | |
397 | _error->Errno("rename",_("Failed to rename %s to %s"), | |
398 | I->TmpFile.Name().c_str(),I->Output.c_str()); | |
399 | I->TmpFile.Close(); | |
400 | } | |
401 | ||
402 | return !_error->PendingError(); | |
403 | } | |
404 | /*}}}*/ | |
405 |