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b2e465d6 AL |
1 | // -*- mode: cpp; mode: fold -*- |
2 | // Description /*{{{*/ | |
7db98ffc | 3 | // $Id: extracttar.cc,v 1.8.2.1 2004/01/16 18:58:50 mdz Exp $ |
b2e465d6 AL |
4 | /* ###################################################################### |
5 | ||
6 | Extract a Tar - Tar Extractor | |
7 | ||
8 | Some performance measurements showed that zlib performed quite poorly | |
9 | in comparision to a forked gzip process. This tar extractor makes use | |
10 | of the fact that dup'd file descriptors have the same seek pointer | |
11 | and that gzip will not read past the end of a compressed stream, | |
12 | even if there is more data. We use the dup property to track extraction | |
13 | progress and the gzip feature to just feed gzip a fd in the middle | |
14 | of an AR file. | |
15 | ||
16 | ##################################################################### */ | |
17 | /*}}}*/ | |
18 | // Include Files /*{{{*/ | |
ea542140 | 19 | #include<config.h> |
b2e465d6 | 20 | |
472ff00e | 21 | #include <apt-pkg/dirstream.h> |
ea542140 | 22 | #include <apt-pkg/extracttar.h> |
b2e465d6 AL |
23 | #include <apt-pkg/error.h> |
24 | #include <apt-pkg/strutl.h> | |
25 | #include <apt-pkg/configuration.h> | |
aea7f4c8 | 26 | #include <apt-pkg/macros.h> |
b2e465d6 AL |
27 | |
28 | #include <stdlib.h> | |
29 | #include <unistd.h> | |
30 | #include <signal.h> | |
31 | #include <fcntl.h> | |
90f057fd | 32 | #include <iostream> |
ea542140 | 33 | |
d77559ac | 34 | #include <apti18n.h> |
b2e465d6 | 35 | /*}}}*/ |
d77559ac | 36 | |
584e4558 | 37 | using namespace std; |
4520bfdf | 38 | |
b2e465d6 AL |
39 | // The on disk header for a tar file. |
40 | struct ExtractTar::TarHeader | |
41 | { | |
42 | char Name[100]; | |
43 | char Mode[8]; | |
44 | char UserID[8]; | |
45 | char GroupID[8]; | |
46 | char Size[12]; | |
47 | char MTime[12]; | |
48 | char Checksum[8]; | |
49 | char LinkFlag; | |
50 | char LinkName[100]; | |
51 | char MagicNumber[8]; | |
52 | char UserName[32]; | |
53 | char GroupName[32]; | |
54 | char Major[8]; | |
55 | char Minor[8]; | |
56 | }; | |
57 | ||
58 | // ExtractTar::ExtractTar - Constructor /*{{{*/ | |
59 | // --------------------------------------------------------------------- | |
60 | /* */ | |
b21c0438 MZ |
61 | ExtractTar::ExtractTar(FileFd &Fd,unsigned long Max,string DecompressionProgram) : File(Fd), |
62 | MaxInSize(Max), DecompressProg(DecompressionProgram) | |
b2e465d6 AL |
63 | |
64 | { | |
65 | GZPid = -1; | |
66 | InFd = -1; | |
67 | Eof = false; | |
68 | } | |
69 | /*}}}*/ | |
70 | // ExtractTar::ExtractTar - Destructor /*{{{*/ | |
71 | // --------------------------------------------------------------------- | |
72 | /* */ | |
73 | ExtractTar::~ExtractTar() | |
74 | { | |
4520bfdf AL |
75 | // Error close |
76 | Done(true); | |
b2e465d6 AL |
77 | } |
78 | /*}}}*/ | |
79 | // ExtractTar::Done - Reap the gzip sub process /*{{{*/ | |
80 | // --------------------------------------------------------------------- | |
81 | /* If the force flag is given then error messages are suppressed - this | |
82 | means we hit the end of the tar file but there was still gzip data. */ | |
83 | bool ExtractTar::Done(bool Force) | |
84 | { | |
85 | InFd.Close(); | |
86 | if (GZPid <= 0) | |
87 | return true; | |
88 | ||
89 | /* If there is a pending error then we are cleaning up gzip and are | |
90 | not interested in it's failures */ | |
91 | if (_error->PendingError() == true) | |
92 | Force = true; | |
93 | ||
94 | // Make sure we clean it up! | |
95 | kill(GZPid,SIGINT); | |
b21c0438 MZ |
96 | string confvar = string("dir::bin::") + DecompressProg; |
97 | if (ExecWait(GZPid,_config->Find(confvar.c_str(),DecompressProg.c_str()).c_str(), | |
b2e465d6 AL |
98 | Force) == false) |
99 | { | |
100 | GZPid = -1; | |
101 | return Force; | |
102 | } | |
103 | ||
104 | GZPid = -1; | |
105 | return true; | |
106 | } | |
107 | /*}}}*/ | |
108 | // ExtractTar::StartGzip - Startup gzip /*{{{*/ | |
109 | // --------------------------------------------------------------------- | |
110 | /* This creates a gzip sub process that has its input as the file itself. | |
111 | If this tar file is embedded into something like an ar file then | |
112 | gzip will efficiently ignore the extra bits. */ | |
113 | bool ExtractTar::StartGzip() | |
114 | { | |
115 | int Pipes[2]; | |
116 | if (pipe(Pipes) != 0) | |
05eb7df0 | 117 | return _error->Errno("pipe",_("Failed to create pipes")); |
b2e465d6 AL |
118 | |
119 | // Fork off the process | |
120 | GZPid = ExecFork(); | |
121 | ||
122 | // Spawn the subprocess | |
123 | if (GZPid == 0) | |
124 | { | |
125 | // Setup the FDs | |
126 | dup2(Pipes[1],STDOUT_FILENO); | |
127 | dup2(File.Fd(),STDIN_FILENO); | |
128 | int Fd = open("/dev/null",O_RDWR); | |
129 | if (Fd == -1) | |
130 | _exit(101); | |
131 | dup2(Fd,STDERR_FILENO); | |
132 | close(Fd); | |
133 | SetCloseExec(STDOUT_FILENO,false); | |
134 | SetCloseExec(STDIN_FILENO,false); | |
135 | SetCloseExec(STDERR_FILENO,false); | |
136 | ||
137 | const char *Args[3]; | |
b21c0438 | 138 | string confvar = string("dir::bin::") + DecompressProg; |
a9be43ff MV |
139 | string argv0 = _config->Find(confvar.c_str(),DecompressProg.c_str()); |
140 | Args[0] = argv0.c_str(); | |
b2e465d6 AL |
141 | Args[1] = "-d"; |
142 | Args[2] = 0; | |
b21c0438 | 143 | execvp(Args[0],(char **)Args); |
05eb7df0 | 144 | cerr << _("Failed to exec gzip ") << Args[0] << endl; |
b2e465d6 AL |
145 | _exit(100); |
146 | } | |
147 | ||
148 | // Fix up our FDs | |
2448a064 | 149 | InFd.OpenDescriptor(Pipes[0], FileFd::ReadOnly, FileFd::None, true); |
b2e465d6 AL |
150 | close(Pipes[1]); |
151 | return true; | |
152 | } | |
153 | /*}}}*/ | |
154 | // ExtractTar::Go - Perform extraction /*{{{*/ | |
155 | // --------------------------------------------------------------------- | |
156 | /* This reads each 512 byte block from the archive and extracts the header | |
157 | information into the Item structure. Then it resolves the UID/GID and | |
158 | invokes the correct processing function. */ | |
159 | bool ExtractTar::Go(pkgDirStream &Stream) | |
160 | { | |
161 | if (StartGzip() == false) | |
162 | return false; | |
163 | ||
164 | // Loop over all blocks | |
165 | string LastLongLink; | |
166 | string LastLongName; | |
167 | while (1) | |
168 | { | |
169 | bool BadRecord = false; | |
170 | unsigned char Block[512]; | |
171 | if (InFd.Read(Block,sizeof(Block),true) == false) | |
172 | return false; | |
173 | ||
174 | if (InFd.Eof() == true) | |
175 | break; | |
176 | ||
177 | // Get the checksum | |
178 | TarHeader *Tar = (TarHeader *)Block; | |
179 | unsigned long CheckSum; | |
180 | if (StrToNum(Tar->Checksum,CheckSum,sizeof(Tar->Checksum),8) == false) | |
05eb7df0 | 181 | return _error->Error(_("Corrupted archive")); |
b2e465d6 AL |
182 | |
183 | /* Compute the checksum field. The actual checksum is blanked out | |
184 | with spaces so it is not included in the computation */ | |
185 | unsigned long NewSum = 0; | |
186 | memset(Tar->Checksum,' ',sizeof(Tar->Checksum)); | |
187 | for (int I = 0; I != sizeof(Block); I++) | |
188 | NewSum += Block[I]; | |
189 | ||
190 | /* Check for a block of nulls - in this case we kill gzip, GNU tar | |
191 | does this.. */ | |
192 | if (NewSum == ' '*sizeof(Tar->Checksum)) | |
193 | return Done(true); | |
194 | ||
195 | if (NewSum != CheckSum) | |
db0db9fe | 196 | return _error->Error(_("Tar checksum failed, archive corrupted")); |
b2e465d6 AL |
197 | |
198 | // Decode all of the fields | |
199 | pkgDirStream::Item Itm; | |
b2e465d6 | 200 | if (StrToNum(Tar->Mode,Itm.Mode,sizeof(Tar->Mode),8) == false || |
54f2f0a3 NH |
201 | (Base256ToNum(Tar->UserID,Itm.UID,8) == false && |
202 | StrToNum(Tar->UserID,Itm.UID,sizeof(Tar->UserID),8) == false) || | |
203 | (Base256ToNum(Tar->GroupID,Itm.GID,8) == false && | |
204 | StrToNum(Tar->GroupID,Itm.GID,sizeof(Tar->GroupID),8) == false) || | |
205 | (Base256ToNum(Tar->Size,Itm.Size,12) == false && | |
206 | StrToNum(Tar->Size,Itm.Size,sizeof(Tar->Size),8) == false) || | |
207 | (Base256ToNum(Tar->MTime,Itm.MTime,12) == false && | |
208 | StrToNum(Tar->MTime,Itm.MTime,sizeof(Tar->MTime),8) == false) || | |
b2e465d6 AL |
209 | StrToNum(Tar->Major,Itm.Major,sizeof(Tar->Major),8) == false || |
210 | StrToNum(Tar->Minor,Itm.Minor,sizeof(Tar->Minor),8) == false) | |
05eb7df0 | 211 | return _error->Error(_("Corrupted archive")); |
b2e465d6 AL |
212 | |
213 | // Grab the filename | |
214 | if (LastLongName.empty() == false) | |
215 | Itm.Name = (char *)LastLongName.c_str(); | |
216 | else | |
217 | { | |
3c8cda8b | 218 | Tar->Name[sizeof(Tar->Name)-1] = 0; |
b2e465d6 AL |
219 | Itm.Name = Tar->Name; |
220 | } | |
221 | if (Itm.Name[0] == '.' && Itm.Name[1] == '/' && Itm.Name[2] != 0) | |
222 | Itm.Name += 2; | |
223 | ||
224 | // Grab the link target | |
3c8cda8b | 225 | Tar->Name[sizeof(Tar->LinkName)-1] = 0; |
b2e465d6 AL |
226 | Itm.LinkTarget = Tar->LinkName; |
227 | ||
228 | if (LastLongLink.empty() == false) | |
229 | Itm.LinkTarget = (char *)LastLongLink.c_str(); | |
230 | ||
231 | // Convert the type over | |
232 | switch (Tar->LinkFlag) | |
233 | { | |
234 | case NormalFile0: | |
235 | case NormalFile: | |
236 | Itm.Type = pkgDirStream::Item::File; | |
237 | break; | |
238 | ||
239 | case HardLink: | |
240 | Itm.Type = pkgDirStream::Item::HardLink; | |
241 | break; | |
242 | ||
243 | case SymbolicLink: | |
244 | Itm.Type = pkgDirStream::Item::SymbolicLink; | |
245 | break; | |
246 | ||
247 | case CharacterDevice: | |
248 | Itm.Type = pkgDirStream::Item::CharDevice; | |
249 | break; | |
250 | ||
251 | case BlockDevice: | |
252 | Itm.Type = pkgDirStream::Item::BlockDevice; | |
253 | break; | |
254 | ||
255 | case Directory: | |
256 | Itm.Type = pkgDirStream::Item::Directory; | |
257 | break; | |
258 | ||
259 | case FIFO: | |
260 | Itm.Type = pkgDirStream::Item::FIFO; | |
261 | break; | |
262 | ||
263 | case GNU_LongLink: | |
264 | { | |
265 | unsigned long Length = Itm.Size; | |
266 | unsigned char Block[512]; | |
267 | while (Length > 0) | |
268 | { | |
269 | if (InFd.Read(Block,sizeof(Block),true) == false) | |
270 | return false; | |
271 | if (Length <= sizeof(Block)) | |
272 | { | |
273 | LastLongLink.append(Block,Block+sizeof(Block)); | |
274 | break; | |
275 | } | |
276 | LastLongLink.append(Block,Block+sizeof(Block)); | |
277 | Length -= sizeof(Block); | |
278 | } | |
279 | continue; | |
280 | } | |
281 | ||
282 | case GNU_LongName: | |
283 | { | |
284 | unsigned long Length = Itm.Size; | |
285 | unsigned char Block[512]; | |
286 | while (Length > 0) | |
287 | { | |
288 | if (InFd.Read(Block,sizeof(Block),true) == false) | |
289 | return false; | |
290 | if (Length < sizeof(Block)) | |
291 | { | |
292 | LastLongName.append(Block,Block+sizeof(Block)); | |
293 | break; | |
294 | } | |
295 | LastLongName.append(Block,Block+sizeof(Block)); | |
296 | Length -= sizeof(Block); | |
297 | } | |
298 | continue; | |
299 | } | |
300 | ||
301 | default: | |
302 | BadRecord = true; | |
4c6a9fad | 303 | _error->Warning(_("Unknown TAR header type %u, member %s"),(unsigned)Tar->LinkFlag,Tar->Name); |
b2e465d6 AL |
304 | break; |
305 | } | |
306 | ||
307 | int Fd = -1; | |
308 | if (BadRecord == false) | |
309 | if (Stream.DoItem(Itm,Fd) == false) | |
310 | return false; | |
311 | ||
312 | // Copy the file over the FD | |
313 | unsigned long Size = Itm.Size; | |
314 | while (Size != 0) | |
315 | { | |
316 | unsigned char Junk[32*1024]; | |
42ab8223 | 317 | unsigned long Read = min(Size,(unsigned long)sizeof(Junk)); |
b2e465d6 AL |
318 | if (InFd.Read(Junk,((Read+511)/512)*512) == false) |
319 | return false; | |
320 | ||
321 | if (BadRecord == false) | |
322 | { | |
323 | if (Fd > 0) | |
324 | { | |
325 | if (write(Fd,Junk,Read) != (signed)Read) | |
326 | return Stream.Fail(Itm,Fd); | |
327 | } | |
328 | else | |
329 | { | |
330 | /* An Fd of -2 means to send to a special processing | |
331 | function */ | |
332 | if (Fd == -2) | |
333 | if (Stream.Process(Itm,Junk,Read,Itm.Size - Size) == false) | |
334 | return Stream.Fail(Itm,Fd); | |
335 | } | |
336 | } | |
337 | ||
338 | Size -= Read; | |
339 | } | |
340 | ||
341 | // And finish up | |
59152cdb | 342 | if (BadRecord == false) |
b2e465d6 AL |
343 | if (Stream.FinishedFile(Itm,Fd) == false) |
344 | return false; | |
345 | ||
346 | LastLongName.erase(); | |
347 | LastLongLink.erase(); | |
348 | } | |
349 | ||
350 | return Done(false); | |
351 | } | |
352 | /*}}}*/ |