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da6ee469 JF |
1 | // -*- mode: cpp; mode: fold -*- |
2 | // Description /*{{{*/ | |
3 | // $Id: dpkgpm.cc,v 1.28 2004/01/27 02:25:01 mdz Exp $ | |
4 | /* ###################################################################### | |
5 | ||
6 | DPKG Package Manager - Provide an interface to dpkg | |
7 | ||
8 | ##################################################################### */ | |
9 | /*}}}*/ | |
10 | // Includes /*{{{*/ | |
da6ee469 JF |
11 | #include <apt-pkg/dpkgpm.h> |
12 | #include <apt-pkg/error.h> | |
13 | #include <apt-pkg/configuration.h> | |
14 | #include <apt-pkg/depcache.h> | |
15 | #include <apt-pkg/strutl.h> | |
00ec24d0 JF |
16 | #include <apti18n.h> |
17 | #include <apt-pkg/fileutl.h> | |
da6ee469 JF |
18 | |
19 | #include <unistd.h> | |
20 | #include <stdlib.h> | |
21 | #include <fcntl.h> | |
00ec24d0 | 22 | #include <sys/select.h> |
da6ee469 JF |
23 | #include <sys/types.h> |
24 | #include <sys/wait.h> | |
25 | #include <signal.h> | |
26 | #include <errno.h> | |
27 | #include <stdio.h> | |
00ec24d0 JF |
28 | #include <string.h> |
29 | #include <algorithm> | |
da6ee469 JF |
30 | #include <sstream> |
31 | #include <map> | |
32 | ||
00ec24d0 JF |
33 | #include <termios.h> |
34 | #include <unistd.h> | |
35 | #include <sys/ioctl.h> | |
36 | #include <sys/stat.h> | |
37 | #include <util.h> | |
38 | ||
da6ee469 JF |
39 | #include <config.h> |
40 | #include <apti18n.h> | |
41 | /*}}}*/ | |
42 | ||
43 | using namespace std; | |
44 | ||
00ec24d0 JF |
45 | namespace |
46 | { | |
47 | // Maps the dpkg "processing" info to human readable names. Entry 0 | |
48 | // of each array is the key, entry 1 is the value. | |
49 | const std::pair<const char *, const char *> PackageProcessingOps[] = { | |
50 | std::make_pair("install", N_("Installing %s")), | |
51 | std::make_pair("configure", N_("Configuring %s")), | |
52 | std::make_pair("remove", N_("Removing %s")), | |
53 | std::make_pair("trigproc", N_("Running post-installation trigger %s")) | |
54 | }; | |
55 | ||
56 | const std::pair<const char *, const char *> * const PackageProcessingOpsBegin = PackageProcessingOps; | |
57 | const std::pair<const char *, const char *> * const PackageProcessingOpsEnd = PackageProcessingOps + sizeof(PackageProcessingOps) / sizeof(PackageProcessingOps[0]); | |
58 | ||
59 | // Predicate to test whether an entry in the PackageProcessingOps | |
60 | // array matches a string. | |
61 | class MatchProcessingOp | |
62 | { | |
63 | const char *target; | |
64 | ||
65 | public: | |
66 | MatchProcessingOp(const char *the_target) | |
67 | : target(the_target) | |
68 | { | |
69 | } | |
70 | ||
71 | bool operator()(const std::pair<const char *, const char *> &pair) const | |
72 | { | |
73 | return strcmp(pair.first, target) == 0; | |
74 | } | |
75 | }; | |
76 | } | |
77 | ||
da6ee469 JF |
78 | // DPkgPM::pkgDPkgPM - Constructor /*{{{*/ |
79 | // --------------------------------------------------------------------- | |
80 | /* */ | |
00ec24d0 JF |
81 | pkgDPkgPM::pkgDPkgPM(pkgDepCache *Cache) |
82 | : pkgPackageManager(Cache), dpkgbuf_pos(0), | |
83 | term_out(NULL), PackagesDone(0), PackagesTotal(0) | |
da6ee469 JF |
84 | { |
85 | } | |
86 | /*}}}*/ | |
87 | // DPkgPM::pkgDPkgPM - Destructor /*{{{*/ | |
88 | // --------------------------------------------------------------------- | |
89 | /* */ | |
90 | pkgDPkgPM::~pkgDPkgPM() | |
91 | { | |
92 | } | |
93 | /*}}}*/ | |
94 | // DPkgPM::Install - Install a package /*{{{*/ | |
95 | // --------------------------------------------------------------------- | |
96 | /* Add an install operation to the sequence list */ | |
97 | bool pkgDPkgPM::Install(PkgIterator Pkg,string File) | |
98 | { | |
99 | if (File.empty() == true || Pkg.end() == true) | |
100 | return _error->Error("Internal Error, No file name for %s",Pkg.Name()); | |
101 | ||
102 | List.push_back(Item(Item::Install,Pkg,File)); | |
103 | return true; | |
104 | } | |
105 | /*}}}*/ | |
106 | // DPkgPM::Configure - Configure a package /*{{{*/ | |
107 | // --------------------------------------------------------------------- | |
108 | /* Add a configure operation to the sequence list */ | |
109 | bool pkgDPkgPM::Configure(PkgIterator Pkg) | |
110 | { | |
111 | if (Pkg.end() == true) | |
112 | return false; | |
113 | ||
114 | List.push_back(Item(Item::Configure,Pkg)); | |
115 | return true; | |
116 | } | |
117 | /*}}}*/ | |
118 | // DPkgPM::Remove - Remove a package /*{{{*/ | |
119 | // --------------------------------------------------------------------- | |
120 | /* Add a remove operation to the sequence list */ | |
121 | bool pkgDPkgPM::Remove(PkgIterator Pkg,bool Purge) | |
122 | { | |
123 | if (Pkg.end() == true) | |
124 | return false; | |
125 | ||
126 | if (Purge == true) | |
127 | List.push_back(Item(Item::Purge,Pkg)); | |
128 | else | |
129 | List.push_back(Item(Item::Remove,Pkg)); | |
130 | return true; | |
131 | } | |
132 | /*}}}*/ | |
da6ee469 JF |
133 | // DPkgPM::SendV2Pkgs - Send version 2 package info /*{{{*/ |
134 | // --------------------------------------------------------------------- | |
135 | /* This is part of the helper script communication interface, it sends | |
136 | very complete information down to the other end of the pipe.*/ | |
137 | bool pkgDPkgPM::SendV2Pkgs(FILE *F) | |
138 | { | |
139 | fprintf(F,"VERSION 2\n"); | |
140 | ||
141 | /* Write out all of the configuration directives by walking the | |
142 | configuration tree */ | |
143 | const Configuration::Item *Top = _config->Tree(0); | |
144 | for (; Top != 0;) | |
145 | { | |
146 | if (Top->Value.empty() == false) | |
147 | { | |
148 | fprintf(F,"%s=%s\n", | |
149 | QuoteString(Top->FullTag(),"=\"\n").c_str(), | |
150 | QuoteString(Top->Value,"\n").c_str()); | |
151 | } | |
152 | ||
153 | if (Top->Child != 0) | |
154 | { | |
155 | Top = Top->Child; | |
156 | continue; | |
157 | } | |
158 | ||
159 | while (Top != 0 && Top->Next == 0) | |
160 | Top = Top->Parent; | |
161 | if (Top != 0) | |
162 | Top = Top->Next; | |
163 | } | |
164 | fprintf(F,"\n"); | |
165 | ||
166 | // Write out the package actions in order. | |
167 | for (vector<Item>::iterator I = List.begin(); I != List.end(); I++) | |
168 | { | |
169 | pkgDepCache::StateCache &S = Cache[I->Pkg]; | |
170 | ||
171 | fprintf(F,"%s ",I->Pkg.Name()); | |
172 | // Current version | |
173 | if (I->Pkg->CurrentVer == 0) | |
174 | fprintf(F,"- "); | |
175 | else | |
176 | fprintf(F,"%s ",I->Pkg.CurrentVer().VerStr()); | |
177 | ||
178 | // Show the compare operator | |
179 | // Target version | |
180 | if (S.InstallVer != 0) | |
181 | { | |
182 | int Comp = 2; | |
183 | if (I->Pkg->CurrentVer != 0) | |
184 | Comp = S.InstVerIter(Cache).CompareVer(I->Pkg.CurrentVer()); | |
185 | if (Comp < 0) | |
186 | fprintf(F,"> "); | |
187 | if (Comp == 0) | |
188 | fprintf(F,"= "); | |
189 | if (Comp > 0) | |
190 | fprintf(F,"< "); | |
191 | fprintf(F,"%s ",S.InstVerIter(Cache).VerStr()); | |
192 | } | |
193 | else | |
194 | fprintf(F,"> - "); | |
195 | ||
196 | // Show the filename/operation | |
197 | if (I->Op == Item::Install) | |
198 | { | |
199 | // No errors here.. | |
200 | if (I->File[0] != '/') | |
201 | fprintf(F,"**ERROR**\n"); | |
202 | else | |
203 | fprintf(F,"%s\n",I->File.c_str()); | |
204 | } | |
205 | if (I->Op == Item::Configure) | |
206 | fprintf(F,"**CONFIGURE**\n"); | |
207 | if (I->Op == Item::Remove || | |
208 | I->Op == Item::Purge) | |
209 | fprintf(F,"**REMOVE**\n"); | |
210 | ||
211 | if (ferror(F) != 0) | |
212 | return false; | |
213 | } | |
214 | return true; | |
215 | } | |
216 | /*}}}*/ | |
217 | // DPkgPM::RunScriptsWithPkgs - Run scripts with package names on stdin /*{{{*/ | |
218 | // --------------------------------------------------------------------- | |
219 | /* This looks for a list of scripts to run from the configuration file | |
220 | each one is run and is fed on standard input a list of all .deb files | |
221 | that are due to be installed. */ | |
222 | bool pkgDPkgPM::RunScriptsWithPkgs(const char *Cnf) | |
223 | { | |
224 | Configuration::Item const *Opts = _config->Tree(Cnf); | |
225 | if (Opts == 0 || Opts->Child == 0) | |
226 | return true; | |
227 | Opts = Opts->Child; | |
228 | ||
229 | unsigned int Count = 1; | |
230 | for (; Opts != 0; Opts = Opts->Next, Count++) | |
231 | { | |
232 | if (Opts->Value.empty() == true) | |
233 | continue; | |
234 | ||
235 | // Determine the protocol version | |
236 | string OptSec = Opts->Value; | |
237 | string::size_type Pos; | |
238 | if ((Pos = OptSec.find(' ')) == string::npos || Pos == 0) | |
239 | Pos = OptSec.length(); | |
240 | OptSec = "DPkg::Tools::Options::" + string(Opts->Value.c_str(),Pos); | |
241 | ||
242 | unsigned int Version = _config->FindI(OptSec+"::Version",1); | |
243 | ||
244 | // Create the pipes | |
245 | int Pipes[2]; | |
246 | if (pipe(Pipes) != 0) | |
247 | return _error->Errno("pipe","Failed to create IPC pipe to subprocess"); | |
248 | SetCloseExec(Pipes[0],true); | |
249 | SetCloseExec(Pipes[1],true); | |
250 | ||
251 | // Purified Fork for running the script | |
252 | pid_t Process = ExecFork(); | |
253 | if (Process == 0) | |
254 | { | |
255 | // Setup the FDs | |
256 | dup2(Pipes[0],STDIN_FILENO); | |
257 | SetCloseExec(STDOUT_FILENO,false); | |
258 | SetCloseExec(STDIN_FILENO,false); | |
259 | SetCloseExec(STDERR_FILENO,false); | |
260 | ||
261 | const char *Args[4]; | |
262 | Args[0] = "/bin/sh"; | |
263 | Args[1] = "-c"; | |
264 | Args[2] = Opts->Value.c_str(); | |
265 | Args[3] = 0; | |
266 | execv(Args[0],(char **)Args); | |
267 | _exit(100); | |
268 | } | |
269 | close(Pipes[0]); | |
270 | FILE *F = fdopen(Pipes[1],"w"); | |
271 | if (F == 0) | |
272 | return _error->Errno("fdopen","Faild to open new FD"); | |
273 | ||
274 | // Feed it the filenames. | |
275 | bool Die = false; | |
276 | if (Version <= 1) | |
277 | { | |
278 | for (vector<Item>::iterator I = List.begin(); I != List.end(); I++) | |
279 | { | |
280 | // Only deal with packages to be installed from .deb | |
281 | if (I->Op != Item::Install) | |
282 | continue; | |
283 | ||
284 | // No errors here.. | |
285 | if (I->File[0] != '/') | |
286 | continue; | |
287 | ||
288 | /* Feed the filename of each package that is pending install | |
289 | into the pipe. */ | |
290 | fprintf(F,"%s\n",I->File.c_str()); | |
291 | if (ferror(F) != 0) | |
292 | { | |
293 | Die = true; | |
294 | break; | |
295 | } | |
296 | } | |
297 | } | |
298 | else | |
299 | Die = !SendV2Pkgs(F); | |
300 | ||
301 | fclose(F); | |
302 | ||
303 | // Clean up the sub process | |
304 | if (ExecWait(Process,Opts->Value.c_str()) == false) | |
305 | return _error->Error("Failure running script %s",Opts->Value.c_str()); | |
306 | } | |
307 | ||
308 | return true; | |
309 | } | |
00ec24d0 JF |
310 | |
311 | /*}}}*/ | |
312 | // DPkgPM::DoStdin - Read stdin and pass to slave pty /*{{{*/ | |
313 | // --------------------------------------------------------------------- | |
314 | /* | |
315 | */ | |
316 | void pkgDPkgPM::DoStdin(int master) | |
317 | { | |
318 | unsigned char input_buf[256] = {0,}; | |
319 | ssize_t len = read(0, input_buf, sizeof(input_buf)); | |
320 | if (len) | |
321 | write(master, input_buf, len); | |
322 | else | |
323 | stdin_is_dev_null = true; | |
324 | } | |
325 | /*}}}*/ | |
326 | // DPkgPM::DoTerminalPty - Read the terminal pty and write log /*{{{*/ | |
327 | // --------------------------------------------------------------------- | |
328 | /* | |
329 | * read the terminal pty and write log | |
330 | */ | |
331 | void pkgDPkgPM::DoTerminalPty(int master) | |
332 | { | |
333 | unsigned char term_buf[1024] = {0,0, }; | |
334 | ||
335 | ssize_t len=read(master, term_buf, sizeof(term_buf)); | |
336 | if(len == -1 && errno == EIO) | |
337 | { | |
338 | // this happens when the child is about to exit, we | |
339 | // give it time to actually exit, otherwise we run | |
340 | // into a race | |
341 | usleep(500000); | |
342 | return; | |
343 | } | |
344 | if(len <= 0) | |
345 | return; | |
346 | write(1, term_buf, len); | |
347 | if(term_out) | |
348 | fwrite(term_buf, len, sizeof(char), term_out); | |
349 | } | |
da6ee469 | 350 | /*}}}*/ |
00ec24d0 JF |
351 | // DPkgPM::ProcessDpkgStatusBuf /*{{{*/ |
352 | // --------------------------------------------------------------------- | |
353 | /* | |
354 | */ | |
355 | void pkgDPkgPM::ProcessDpkgStatusLine(int OutStatusFd, char *line) | |
356 | { | |
357 | // the status we output | |
358 | ostringstream status; | |
359 | ||
360 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
361 | std::clog << "got from dpkg '" << line << "'" << std::endl; | |
362 | ||
363 | ||
364 | /* dpkg sends strings like this: | |
365 | 'status: <pkg>: <pkg qstate>' | |
366 | errors look like this: | |
367 | 'status: /var/cache/apt/archives/krecipes_0.8.1-0ubuntu1_i386.deb : error : trying to overwrite `/usr/share/doc/kde/HTML/en/krecipes/krectip.png', which is also in package krecipes-data | |
368 | and conffile-prompt like this | |
369 | 'status: conffile-prompt: conffile : 'current-conffile' 'new-conffile' useredited distedited | |
370 | ||
371 | Newer versions of dpkg sent also: | |
372 | 'processing: install: pkg' | |
373 | 'processing: configure: pkg' | |
374 | 'processing: remove: pkg' | |
375 | 'processing: trigproc: trigger' | |
376 | ||
377 | */ | |
378 | char* list[5]; | |
379 | // dpkg sends multiline error messages sometimes (see | |
380 | // #374195 for a example. we should support this by | |
381 | // either patching dpkg to not send multiline over the | |
382 | // statusfd or by rewriting the code here to deal with | |
383 | // it. for now we just ignore it and not crash | |
384 | TokSplitString(':', line, list, sizeof(list)/sizeof(list[0])); | |
385 | if( list[0] == NULL || list[1] == NULL || list[2] == NULL) | |
386 | { | |
387 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
388 | std::clog << "ignoring line: not enough ':'" << std::endl; | |
389 | return; | |
390 | } | |
391 | char *pkg = list[1]; | |
392 | char *action = _strstrip(list[2]); | |
393 | ||
394 | // 'processing' from dpkg looks like | |
395 | // 'processing: action: pkg' | |
396 | if(strncmp(list[0], "processing", strlen("processing")) == 0) | |
397 | { | |
398 | char s[200]; | |
399 | char *pkg_or_trigger = _strstrip(list[2]); | |
400 | action =_strstrip( list[1]); | |
401 | const std::pair<const char *, const char *> * const iter = | |
402 | std::find_if(PackageProcessingOpsBegin, | |
403 | PackageProcessingOpsEnd, | |
404 | MatchProcessingOp(action)); | |
405 | if(iter == PackageProcessingOpsEnd) | |
406 | { | |
407 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
408 | std::clog << "ignoring unknwon action: " << action << std::endl; | |
409 | return; | |
410 | } | |
411 | snprintf(s, sizeof(s), _(iter->second), pkg_or_trigger); | |
412 | ||
413 | status << "pmstatus:" << pkg_or_trigger | |
414 | << ":" << (PackagesDone/float(PackagesTotal)*100.0) | |
415 | << ":" << s | |
416 | << endl; | |
417 | if(OutStatusFd > 0) | |
418 | write(OutStatusFd, status.str().c_str(), status.str().size()); | |
419 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
420 | std::clog << "send: '" << status.str() << "'" << endl; | |
421 | return; | |
422 | } | |
423 | ||
424 | if(strncmp(action,"error",strlen("error")) == 0) | |
425 | { | |
426 | status << "pmerror:" << list[1] | |
427 | << ":" << (PackagesDone/float(PackagesTotal)*100.0) | |
428 | << ":" << list[3] | |
429 | << endl; | |
430 | if(OutStatusFd > 0) | |
431 | write(OutStatusFd, status.str().c_str(), status.str().size()); | |
432 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
433 | std::clog << "send: '" << status.str() << "'" << endl; | |
434 | return; | |
435 | } | |
436 | if(strncmp(action,"conffile",strlen("conffile")) == 0) | |
437 | { | |
438 | status << "pmconffile:" << list[1] | |
439 | << ":" << (PackagesDone/float(PackagesTotal)*100.0) | |
440 | << ":" << list[3] | |
441 | << endl; | |
442 | if(OutStatusFd > 0) | |
443 | write(OutStatusFd, status.str().c_str(), status.str().size()); | |
444 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
445 | std::clog << "send: '" << status.str() << "'" << endl; | |
446 | return; | |
447 | } | |
448 | ||
449 | vector<struct DpkgState> &states = PackageOps[pkg]; | |
450 | const char *next_action = NULL; | |
451 | if(PackageOpsDone[pkg] < states.size()) | |
452 | next_action = states[PackageOpsDone[pkg]].state; | |
453 | // check if the package moved to the next dpkg state | |
454 | if(next_action && (strcmp(action, next_action) == 0)) | |
455 | { | |
456 | // only read the translation if there is actually a next | |
457 | // action | |
458 | const char *translation = _(states[PackageOpsDone[pkg]].str); | |
459 | char s[200]; | |
460 | snprintf(s, sizeof(s), translation, pkg); | |
461 | ||
462 | // we moved from one dpkg state to a new one, report that | |
463 | PackageOpsDone[pkg]++; | |
464 | PackagesDone++; | |
465 | // build the status str | |
466 | status << "pmstatus:" << pkg | |
467 | << ":" << (PackagesDone/float(PackagesTotal)*100.0) | |
468 | << ":" << s | |
469 | << endl; | |
470 | if(OutStatusFd > 0) | |
471 | write(OutStatusFd, status.str().c_str(), status.str().size()); | |
472 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
473 | std::clog << "send: '" << status.str() << "'" << endl; | |
474 | } | |
475 | if (_config->FindB("Debug::pkgDPkgProgressReporting",false) == true) | |
476 | std::clog << "(parsed from dpkg) pkg: " << pkg | |
477 | << " action: " << action << endl; | |
478 | } | |
479 | ||
480 | // DPkgPM::DoDpkgStatusFd /*{{{*/ | |
481 | // --------------------------------------------------------------------- | |
482 | /* | |
483 | */ | |
484 | void pkgDPkgPM::DoDpkgStatusFd(int statusfd, int OutStatusFd) | |
485 | { | |
486 | char *p, *q; | |
487 | int len; | |
488 | ||
489 | len=read(statusfd, &dpkgbuf[dpkgbuf_pos], sizeof(dpkgbuf)-dpkgbuf_pos); | |
490 | dpkgbuf_pos += len; | |
491 | if(len <= 0) | |
492 | return; | |
493 | ||
494 | // process line by line if we have a buffer | |
495 | p = q = dpkgbuf; | |
496 | while((q=(char*)memchr(p, '\n', dpkgbuf+dpkgbuf_pos-p)) != NULL) | |
497 | { | |
498 | *q = 0; | |
499 | ProcessDpkgStatusLine(OutStatusFd, p); | |
500 | p=q+1; // continue with next line | |
501 | } | |
502 | ||
503 | // now move the unprocessed bits (after the final \n that is now a 0x0) | |
504 | // to the start and update dpkgbuf_pos | |
505 | void *memrchr(void const *, int, size_t); | |
506 | p = (char*)memrchr(dpkgbuf, 0, dpkgbuf_pos); | |
507 | if(p == NULL) | |
508 | return; | |
509 | ||
510 | // we are interessted in the first char *after* 0x0 | |
511 | p++; | |
512 | ||
513 | // move the unprocessed tail to the start and update pos | |
514 | memmove(dpkgbuf, p, p-dpkgbuf); | |
515 | dpkgbuf_pos = dpkgbuf+dpkgbuf_pos-p; | |
516 | } | |
517 | /*}}}*/ | |
518 | ||
519 | bool pkgDPkgPM::OpenLog() | |
520 | { | |
521 | string logdir = _config->FindDir("Dir::Log"); | |
522 | if(not FileExists(logdir)) | |
523 | return _error->Error(_("Directory '%s' missing"), logdir.c_str()); | |
524 | string logfile_name = flCombine(logdir, | |
525 | _config->Find("Dir::Log::Terminal")); | |
526 | if (!logfile_name.empty()) | |
527 | { | |
528 | term_out = fopen(logfile_name.c_str(),"a"); | |
529 | chmod(logfile_name.c_str(), 0600); | |
530 | // output current time | |
531 | char outstr[200]; | |
532 | time_t t = time(NULL); | |
533 | struct tm *tmp = localtime(&t); | |
534 | strftime(outstr, sizeof(outstr), "%F %T", tmp); | |
535 | fprintf(term_out, "\nLog started: "); | |
536 | fprintf(term_out, "%s", outstr); | |
537 | fprintf(term_out, "\n"); | |
538 | } | |
539 | return true; | |
540 | } | |
541 | ||
542 | bool pkgDPkgPM::CloseLog() | |
543 | { | |
544 | if(term_out) | |
545 | { | |
546 | char outstr[200]; | |
547 | time_t t = time(NULL); | |
548 | struct tm *tmp = localtime(&t); | |
549 | strftime(outstr, sizeof(outstr), "%F %T", tmp); | |
550 | fprintf(term_out, "Log ended: "); | |
551 | fprintf(term_out, "%s", outstr); | |
552 | fprintf(term_out, "\n"); | |
553 | fclose(term_out); | |
554 | } | |
555 | term_out = NULL; | |
556 | return true; | |
557 | } | |
558 | ||
559 | /*{{{*/ | |
560 | // This implements a racy version of pselect for those architectures | |
561 | // that don't have a working implementation. | |
562 | // FIXME: Probably can be removed on Lenny+1 | |
563 | static int racy_pselect(int nfds, fd_set *readfds, fd_set *writefds, | |
564 | fd_set *exceptfds, const struct timespec *timeout, | |
565 | const sigset_t *sigmask) | |
566 | { | |
567 | sigset_t origmask; | |
568 | struct timeval tv; | |
569 | int retval; | |
570 | ||
571 | tv.tv_sec = timeout->tv_sec; | |
572 | tv.tv_usec = timeout->tv_nsec/1000; | |
573 | ||
574 | sigprocmask(SIG_SETMASK, sigmask, &origmask); | |
575 | retval = select(nfds, readfds, writefds, exceptfds, &tv); | |
576 | sigprocmask(SIG_SETMASK, &origmask, 0); | |
577 | return retval; | |
578 | } | |
579 | /*}}}*/ | |
580 | ||
da6ee469 JF |
581 | // DPkgPM::Go - Run the sequence /*{{{*/ |
582 | // --------------------------------------------------------------------- | |
583 | /* This globs the operations and calls dpkg | |
584 | * | |
585 | * If it is called with "OutStatusFd" set to a valid file descriptor | |
586 | * apt will report the install progress over this fd. It maps the | |
587 | * dpkg states a package goes through to human readable (and i10n-able) | |
588 | * names and calculates a percentage for each step. | |
589 | */ | |
590 | bool pkgDPkgPM::Go(int OutStatusFd) | |
591 | { | |
592 | unsigned int MaxArgs = _config->FindI("Dpkg::MaxArgs",8*1024); | |
593 | unsigned int MaxArgBytes = _config->FindI("Dpkg::MaxArgBytes",32*1024); | |
00ec24d0 | 594 | bool NoTriggers = _config->FindB("DPkg::NoTriggers",false); |
da6ee469 JF |
595 | |
596 | if (RunScripts("DPkg::Pre-Invoke") == false) | |
597 | return false; | |
598 | ||
599 | if (RunScriptsWithPkgs("DPkg::Pre-Install-Pkgs") == false) | |
600 | return false; | |
00ec24d0 | 601 | |
da6ee469 JF |
602 | // map the dpkg states to the operations that are performed |
603 | // (this is sorted in the same way as Item::Ops) | |
00ec24d0 | 604 | static const struct DpkgState DpkgStatesOpMap[][7] = { |
da6ee469 JF |
605 | // Install operation |
606 | { | |
607 | {"half-installed", N_("Preparing %s")}, | |
608 | {"unpacked", N_("Unpacking %s") }, | |
609 | {NULL, NULL} | |
610 | }, | |
611 | // Configure operation | |
612 | { | |
613 | {"unpacked",N_("Preparing to configure %s") }, | |
614 | {"half-configured", N_("Configuring %s") }, | |
00ec24d0 JF |
615 | #if 0 |
616 | {"triggers-awaited", N_("Processing triggers for %s") }, | |
617 | {"triggers-pending", N_("Processing triggers for %s") }, | |
618 | #endif | |
da6ee469 JF |
619 | { "installed", N_("Installed %s")}, |
620 | {NULL, NULL} | |
621 | }, | |
622 | // Remove operation | |
623 | { | |
624 | {"half-configured", N_("Preparing for removal of %s")}, | |
00ec24d0 JF |
625 | #if 0 |
626 | {"triggers-awaited", N_("Preparing for removal of %s")}, | |
627 | {"triggers-pending", N_("Preparing for removal of %s")}, | |
628 | #endif | |
da6ee469 JF |
629 | {"half-installed", N_("Removing %s")}, |
630 | {"config-files", N_("Removed %s")}, | |
631 | {NULL, NULL} | |
632 | }, | |
633 | // Purge operation | |
634 | { | |
635 | {"config-files", N_("Preparing to completely remove %s")}, | |
636 | {"not-installed", N_("Completely removed %s")}, | |
637 | {NULL, NULL} | |
638 | }, | |
639 | }; | |
640 | ||
da6ee469 JF |
641 | // init the PackageOps map, go over the list of packages that |
642 | // that will be [installed|configured|removed|purged] and add | |
643 | // them to the PackageOps map (the dpkg states it goes through) | |
644 | // and the PackageOpsTranslations (human readable strings) | |
645 | for (vector<Item>::iterator I = List.begin(); I != List.end();I++) | |
646 | { | |
647 | string name = (*I).Pkg.Name(); | |
648 | PackageOpsDone[name] = 0; | |
649 | for(int i=0; (DpkgStatesOpMap[(*I).Op][i]).state != NULL; i++) | |
650 | { | |
651 | PackageOps[name].push_back(DpkgStatesOpMap[(*I).Op][i]); | |
00ec24d0 | 652 | PackagesTotal++; |
da6ee469 JF |
653 | } |
654 | } | |
655 | ||
00ec24d0 JF |
656 | stdin_is_dev_null = false; |
657 | ||
658 | // create log | |
659 | OpenLog(); | |
660 | ||
da6ee469 JF |
661 | // this loop is runs once per operation |
662 | for (vector<Item>::iterator I = List.begin(); I != List.end();) | |
663 | { | |
664 | vector<Item>::iterator J = I; | |
665 | for (; J != List.end() && J->Op == I->Op; J++); | |
666 | ||
667 | // Generate the argument list | |
668 | const char *Args[MaxArgs + 50]; | |
669 | if (J - I > (signed)MaxArgs) | |
670 | J = I + MaxArgs; | |
671 | ||
672 | unsigned int n = 0; | |
673 | unsigned long Size = 0; | |
674 | string Tmp = _config->Find("Dir::Bin::dpkg","dpkg"); | |
675 | Args[n++] = Tmp.c_str(); | |
676 | Size += strlen(Args[n-1]); | |
677 | ||
678 | // Stick in any custom dpkg options | |
679 | Configuration::Item const *Opts = _config->Tree("DPkg::Options"); | |
680 | if (Opts != 0) | |
681 | { | |
682 | Opts = Opts->Child; | |
683 | for (; Opts != 0; Opts = Opts->Next) | |
684 | { | |
685 | if (Opts->Value.empty() == true) | |
686 | continue; | |
687 | Args[n++] = Opts->Value.c_str(); | |
688 | Size += Opts->Value.length(); | |
689 | } | |
690 | } | |
691 | ||
692 | char status_fd_buf[20]; | |
693 | int fd[2]; | |
694 | pipe(fd); | |
695 | ||
696 | Args[n++] = "--status-fd"; | |
697 | Size += strlen(Args[n-1]); | |
698 | snprintf(status_fd_buf,sizeof(status_fd_buf),"%i", fd[1]); | |
699 | Args[n++] = status_fd_buf; | |
700 | Size += strlen(Args[n-1]); | |
701 | ||
702 | switch (I->Op) | |
703 | { | |
704 | case Item::Remove: | |
705 | Args[n++] = "--force-depends"; | |
706 | Size += strlen(Args[n-1]); | |
7ae8af64 JF |
707 | Args[n++] = "--force-remove-reinstreq"; |
708 | Size += strlen(Args[n-1]); | |
da6ee469 JF |
709 | Args[n++] = "--force-remove-essential"; |
710 | Size += strlen(Args[n-1]); | |
711 | Args[n++] = "--remove"; | |
712 | Size += strlen(Args[n-1]); | |
713 | break; | |
714 | ||
715 | case Item::Purge: | |
716 | Args[n++] = "--force-depends"; | |
717 | Size += strlen(Args[n-1]); | |
7ae8af64 JF |
718 | Args[n++] = "--force-remove-reinstreq"; |
719 | Size += strlen(Args[n-1]); | |
da6ee469 JF |
720 | Args[n++] = "--force-remove-essential"; |
721 | Size += strlen(Args[n-1]); | |
722 | Args[n++] = "--purge"; | |
723 | Size += strlen(Args[n-1]); | |
724 | break; | |
725 | ||
726 | case Item::Configure: | |
727 | Args[n++] = "--configure"; | |
00ec24d0 JF |
728 | if (NoTriggers) |
729 | Args[n++] = "--no-triggers"; | |
da6ee469 JF |
730 | Size += strlen(Args[n-1]); |
731 | break; | |
732 | ||
733 | case Item::Install: | |
734 | Args[n++] = "--unpack"; | |
735 | Size += strlen(Args[n-1]); | |
00ec24d0 JF |
736 | Args[n++] = "--auto-deconfigure"; |
737 | Size += strlen(Args[n-1]); | |
da6ee469 JF |
738 | break; |
739 | } | |
740 | ||
741 | // Write in the file or package names | |
742 | if (I->Op == Item::Install) | |
743 | { | |
744 | for (;I != J && Size < MaxArgBytes; I++) | |
745 | { | |
746 | if (I->File[0] != '/') | |
747 | return _error->Error("Internal Error, Pathname to install is not absolute '%s'",I->File.c_str()); | |
748 | Args[n++] = I->File.c_str(); | |
749 | Size += strlen(Args[n-1]); | |
750 | } | |
751 | } | |
752 | else | |
753 | { | |
754 | for (;I != J && Size < MaxArgBytes; I++) | |
755 | { | |
756 | Args[n++] = I->Pkg.Name(); | |
757 | Size += strlen(Args[n-1]); | |
758 | } | |
759 | } | |
760 | Args[n] = 0; | |
761 | J = I; | |
762 | ||
763 | if (_config->FindB("Debug::pkgDPkgPM",false) == true) | |
764 | { | |
765 | for (unsigned int k = 0; k != n; k++) | |
766 | clog << Args[k] << ' '; | |
767 | clog << endl; | |
768 | continue; | |
769 | } | |
770 | ||
771 | cout << flush; | |
772 | clog << flush; | |
773 | cerr << flush; | |
774 | ||
775 | typedef void (*sighandler_t)(int); | |
776 | ||
777 | /* Mask off sig int/quit. We do this because dpkg also does when | |
778 | it forks scripts. What happens is that when you hit ctrl-c it sends | |
779 | it to all processes in the group. Since dpkg ignores the signal | |
780 | it doesn't die but we do! So we must also ignore it */ | |
781 | sighandler_t old_SIGQUIT = signal(SIGQUIT,SIG_IGN); | |
782 | sighandler_t old_SIGINT = signal(SIGINT,SIG_IGN); | |
00ec24d0 JF |
783 | |
784 | // ignore SIGHUP as well (debian #463030) | |
785 | sighandler_t old_SIGHUP = signal(SIGHUP,SIG_IGN); | |
786 | ||
787 | struct termios tt; | |
788 | struct termios tt_out; | |
789 | struct winsize win; | |
790 | int master; | |
791 | int slave; | |
792 | ||
793 | // FIXME: setup sensible signal handling (*ick*) | |
794 | tcgetattr(0, &tt); | |
795 | tcgetattr(1, &tt_out); | |
796 | ioctl(0, TIOCGWINSZ, (char *)&win); | |
797 | if (openpty(&master, &slave, NULL, &tt_out, &win) < 0) | |
798 | { | |
799 | const char *s = _("Can not write log, openpty() " | |
800 | "failed (/dev/pts not mounted?)\n"); | |
801 | fprintf(stderr, "%s",s); | |
802 | fprintf(term_out, "%s",s); | |
803 | master = slave = -1; | |
804 | } else { | |
805 | struct termios rtt; | |
806 | rtt = tt; | |
807 | cfmakeraw(&rtt); | |
808 | rtt.c_lflag &= ~ECHO; | |
809 | tcsetattr(0, TCSAFLUSH, &rtt); | |
810 | } | |
811 | ||
da6ee469 JF |
812 | // Fork dpkg |
813 | pid_t Child; | |
814 | _config->Set("APT::Keep-Fds::",fd[1]); | |
815 | Child = ExecFork(); | |
816 | ||
817 | // This is the child | |
818 | if (Child == 0) | |
819 | { | |
00ec24d0 JF |
820 | if(slave >= 0 && master >= 0) |
821 | { | |
822 | setsid(); | |
823 | ioctl(slave, TIOCSCTTY, 0); | |
824 | close(master); | |
825 | dup2(slave, 0); | |
826 | dup2(slave, 1); | |
827 | dup2(slave, 2); | |
828 | close(slave); | |
829 | } | |
da6ee469 | 830 | close(fd[0]); // close the read end of the pipe |
00ec24d0 | 831 | |
da6ee469 JF |
832 | if (chdir(_config->FindDir("DPkg::Run-Directory","/").c_str()) != 0) |
833 | _exit(100); | |
834 | ||
835 | if (_config->FindB("DPkg::FlushSTDIN",true) == true && isatty(STDIN_FILENO)) | |
836 | { | |
837 | int Flags,dummy; | |
838 | if ((Flags = fcntl(STDIN_FILENO,F_GETFL,dummy)) < 0) | |
839 | _exit(100); | |
840 | ||
841 | // Discard everything in stdin before forking dpkg | |
842 | if (fcntl(STDIN_FILENO,F_SETFL,Flags | O_NONBLOCK) < 0) | |
843 | _exit(100); | |
844 | ||
845 | while (read(STDIN_FILENO,&dummy,1) == 1); | |
846 | ||
847 | if (fcntl(STDIN_FILENO,F_SETFL,Flags & (~(long)O_NONBLOCK)) < 0) | |
848 | _exit(100); | |
849 | } | |
00ec24d0 JF |
850 | |
851 | ||
da6ee469 JF |
852 | /* No Job Control Stop Env is a magic dpkg var that prevents it |
853 | from using sigstop */ | |
00ec24d0 | 854 | putenv((char *)"DPKG_NO_TSTP=yes"); |
da6ee469 JF |
855 | execvp(Args[0],(char **)Args); |
856 | cerr << "Could not exec dpkg!" << endl; | |
857 | _exit(100); | |
858 | } | |
859 | ||
860 | // clear the Keep-Fd again | |
861 | _config->Clear("APT::Keep-Fds",fd[1]); | |
862 | ||
863 | // Wait for dpkg | |
864 | int Status = 0; | |
865 | ||
866 | // we read from dpkg here | |
867 | int _dpkgin = fd[0]; | |
da6ee469 JF |
868 | close(fd[1]); // close the write end of the pipe |
869 | ||
da6ee469 JF |
870 | // the result of the waitpid call |
871 | int res; | |
00ec24d0 JF |
872 | if(slave > 0) |
873 | close(slave); | |
874 | ||
875 | // setups fds | |
876 | fd_set rfds; | |
877 | struct timespec tv; | |
878 | sigset_t sigmask; | |
879 | sigset_t original_sigmask; | |
880 | sigemptyset(&sigmask); | |
881 | sigprocmask(SIG_BLOCK,&sigmask,&original_sigmask); | |
da6ee469 | 882 | |
00ec24d0 | 883 | int select_ret; |
da6ee469 JF |
884 | while ((res=waitpid(Child,&Status, WNOHANG)) != Child) { |
885 | if(res < 0) { | |
886 | // FIXME: move this to a function or something, looks ugly here | |
887 | // error handling, waitpid returned -1 | |
888 | if (errno == EINTR) | |
889 | continue; | |
890 | RunScripts("DPkg::Post-Invoke"); | |
891 | ||
892 | // Restore sig int/quit | |
893 | signal(SIGQUIT,old_SIGQUIT); | |
894 | signal(SIGINT,old_SIGINT); | |
00ec24d0 | 895 | signal(SIGHUP,old_SIGHUP); |
da6ee469 JF |
896 | return _error->Errno("waitpid","Couldn't wait for subprocess"); |
897 | } | |
da6ee469 | 898 | |
00ec24d0 JF |
899 | // wait for input or output here |
900 | FD_ZERO(&rfds); | |
901 | if (!stdin_is_dev_null) | |
902 | FD_SET(0, &rfds); | |
903 | FD_SET(_dpkgin, &rfds); | |
904 | if(master >= 0) | |
905 | FD_SET(master, &rfds); | |
906 | tv.tv_sec = 1; | |
907 | tv.tv_nsec = 0; | |
908 | select_ret = pselect(max(master, _dpkgin)+1, &rfds, NULL, NULL, | |
909 | &tv, &original_sigmask); | |
910 | if (select_ret < 0 && (errno == EINVAL || errno == ENOSYS)) | |
911 | select_ret = racy_pselect(max(master, _dpkgin)+1, &rfds, NULL, | |
912 | NULL, &tv, &original_sigmask); | |
913 | if (select_ret == 0) | |
914 | continue; | |
915 | else if (select_ret < 0 && errno == EINTR) | |
916 | continue; | |
917 | else if (select_ret < 0) | |
918 | { | |
919 | perror("select() returned error"); | |
920 | continue; | |
921 | } | |
da6ee469 | 922 | |
00ec24d0 JF |
923 | if(master >= 0 && FD_ISSET(master, &rfds)) |
924 | DoTerminalPty(master); | |
925 | if(master >= 0 && FD_ISSET(0, &rfds)) | |
926 | DoStdin(master); | |
927 | if(FD_ISSET(_dpkgin, &rfds)) | |
928 | DoDpkgStatusFd(_dpkgin, OutStatusFd); | |
da6ee469 JF |
929 | } |
930 | close(_dpkgin); | |
931 | ||
932 | // Restore sig int/quit | |
933 | signal(SIGQUIT,old_SIGQUIT); | |
934 | signal(SIGINT,old_SIGINT); | |
00ec24d0 JF |
935 | signal(SIGHUP,old_SIGHUP); |
936 | ||
937 | if(master >= 0) | |
938 | { | |
939 | tcsetattr(0, TCSAFLUSH, &tt); | |
940 | close(master); | |
941 | } | |
da6ee469 JF |
942 | |
943 | // Check for an error code. | |
944 | if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0) | |
945 | { | |
946 | // if it was set to "keep-dpkg-runing" then we won't return | |
947 | // here but keep the loop going and just report it as a error | |
948 | // for later | |
949 | bool stopOnError = _config->FindB("Dpkg::StopOnError",true); | |
950 | ||
951 | if(stopOnError) | |
952 | RunScripts("DPkg::Post-Invoke"); | |
953 | ||
954 | if (WIFSIGNALED(Status) != 0 && WTERMSIG(Status) == SIGSEGV) | |
955 | _error->Error("Sub-process %s received a segmentation fault.",Args[0]); | |
956 | else if (WIFEXITED(Status) != 0) | |
957 | _error->Error("Sub-process %s returned an error code (%u)",Args[0],WEXITSTATUS(Status)); | |
958 | else | |
959 | _error->Error("Sub-process %s exited unexpectedly",Args[0]); | |
960 | ||
00ec24d0 JF |
961 | if(stopOnError) |
962 | { | |
963 | CloseLog(); | |
da6ee469 | 964 | return false; |
00ec24d0 | 965 | } |
da6ee469 JF |
966 | } |
967 | } | |
00ec24d0 | 968 | CloseLog(); |
da6ee469 JF |
969 | |
970 | if (RunScripts("DPkg::Post-Invoke") == false) | |
971 | return false; | |
00ec24d0 JF |
972 | |
973 | Cache.writeStateFile(NULL); | |
da6ee469 JF |
974 | return true; |
975 | } | |
976 | /*}}}*/ | |
977 | // pkgDpkgPM::Reset - Dump the contents of the command list /*{{{*/ | |
978 | // --------------------------------------------------------------------- | |
979 | /* */ | |
980 | void pkgDPkgPM::Reset() | |
981 | { | |
982 | List.erase(List.begin(),List.end()); | |
983 | } | |
984 | /*}}}*/ | |
00ec24d0 JF |
985 | |
986 | /* memrchr -- find the last occurrence of a byte in a memory block | |
987 | ||
988 | Copyright (C) 1991, 1993, 1996, 1997, 1999, 2000, 2003, 2004, 2005, | |
989 | 2006, 2007, 2008 Free Software Foundation, Inc. | |
990 | ||
991 | Based on strlen implementation by Torbjorn Granlund (tege@sics.se), | |
992 | with help from Dan Sahlin (dan@sics.se) and | |
993 | commentary by Jim Blandy (jimb@ai.mit.edu); | |
994 | adaptation to memchr suggested by Dick Karpinski (dick@cca.ucsf.edu), | |
995 | and implemented by Roland McGrath (roland@ai.mit.edu). | |
996 | ||
997 | This program is free software: you can redistribute it and/or modify | |
998 | it under the terms of the GNU General Public License as published by | |
999 | the Free Software Foundation; either version 3 of the License, or | |
1000 | (at your option) any later version. | |
1001 | ||
1002 | This program is distributed in the hope that it will be useful, | |
1003 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
1004 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
1005 | GNU General Public License for more details. | |
1006 | ||
1007 | You should have received a copy of the GNU General Public License | |
1008 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
1009 | ||
1010 | #if defined _LIBC | |
1011 | # include <memcopy.h> | |
1012 | #else | |
1013 | # include <config.h> | |
1014 | # define reg_char char | |
1015 | #endif | |
1016 | ||
1017 | #include <string.h> | |
1018 | #include <limits.h> | |
1019 | ||
1020 | #undef __memrchr | |
1021 | #ifdef _LIBC | |
1022 | # undef memrchr | |
1023 | #endif | |
1024 | ||
1025 | #ifndef weak_alias | |
1026 | # define __memrchr memrchr | |
1027 | #endif | |
1028 | ||
1029 | /* Search no more than N bytes of S for C. */ | |
1030 | void * | |
1031 | __memrchr (void const *s, int c_in, size_t n) | |
1032 | { | |
1033 | /* On 32-bit hardware, choosing longword to be a 32-bit unsigned | |
1034 | long instead of a 64-bit uintmax_t tends to give better | |
1035 | performance. On 64-bit hardware, unsigned long is generally 64 | |
1036 | bits already. Change this typedef to experiment with | |
1037 | performance. */ | |
1038 | typedef unsigned long int longword; | |
1039 | ||
1040 | const unsigned char *char_ptr; | |
1041 | const longword *longword_ptr; | |
1042 | longword repeated_one; | |
1043 | longword repeated_c; | |
1044 | unsigned reg_char c; | |
1045 | ||
1046 | c = (unsigned char) c_in; | |
1047 | ||
1048 | /* Handle the last few bytes by reading one byte at a time. | |
1049 | Do this until CHAR_PTR is aligned on a longword boundary. */ | |
1050 | for (char_ptr = (const unsigned char *) s + n; | |
1051 | n > 0 && (size_t) char_ptr % sizeof (longword) != 0; | |
1052 | --n) | |
1053 | if (*--char_ptr == c) | |
1054 | return (void *) char_ptr; | |
1055 | ||
1056 | longword_ptr = (const longword *) char_ptr; | |
1057 | ||
1058 | /* All these elucidatory comments refer to 4-byte longwords, | |
1059 | but the theory applies equally well to any size longwords. */ | |
1060 | ||
1061 | /* Compute auxiliary longword values: | |
1062 | repeated_one is a value which has a 1 in every byte. | |
1063 | repeated_c has c in every byte. */ | |
1064 | repeated_one = 0x01010101; | |
1065 | repeated_c = c | (c << 8); | |
1066 | repeated_c |= repeated_c << 16; | |
1067 | if (0xffffffffU < (longword) -1) | |
1068 | { | |
1069 | repeated_one |= repeated_one << 31 << 1; | |
1070 | repeated_c |= repeated_c << 31 << 1; | |
1071 | if (8 < sizeof (longword)) | |
1072 | { | |
1073 | size_t i; | |
1074 | ||
1075 | for (i = 64; i < sizeof (longword) * 8; i *= 2) | |
1076 | { | |
1077 | repeated_one |= repeated_one << i; | |
1078 | repeated_c |= repeated_c << i; | |
1079 | } | |
1080 | } | |
1081 | } | |
1082 | ||
1083 | /* Instead of the traditional loop which tests each byte, we will test a | |
1084 | longword at a time. The tricky part is testing if *any of the four* | |
1085 | bytes in the longword in question are equal to c. We first use an xor | |
1086 | with repeated_c. This reduces the task to testing whether *any of the | |
1087 | four* bytes in longword1 is zero. | |
1088 | ||
1089 | We compute tmp = | |
1090 | ((longword1 - repeated_one) & ~longword1) & (repeated_one << 7). | |
1091 | That is, we perform the following operations: | |
1092 | 1. Subtract repeated_one. | |
1093 | 2. & ~longword1. | |
1094 | 3. & a mask consisting of 0x80 in every byte. | |
1095 | Consider what happens in each byte: | |
1096 | - If a byte of longword1 is zero, step 1 and 2 transform it into 0xff, | |
1097 | and step 3 transforms it into 0x80. A carry can also be propagated | |
1098 | to more significant bytes. | |
1099 | - If a byte of longword1 is nonzero, let its lowest 1 bit be at | |
1100 | position k (0 <= k <= 7); so the lowest k bits are 0. After step 1, | |
1101 | the byte ends in a single bit of value 0 and k bits of value 1. | |
1102 | After step 2, the result is just k bits of value 1: 2^k - 1. After | |
1103 | step 3, the result is 0. And no carry is produced. | |
1104 | So, if longword1 has only non-zero bytes, tmp is zero. | |
1105 | Whereas if longword1 has a zero byte, call j the position of the least | |
1106 | significant zero byte. Then the result has a zero at positions 0, ..., | |
1107 | j-1 and a 0x80 at position j. We cannot predict the result at the more | |
1108 | significant bytes (positions j+1..3), but it does not matter since we | |
1109 | already have a non-zero bit at position 8*j+7. | |
1110 | ||
1111 | So, the test whether any byte in longword1 is zero is equivalent to | |
1112 | testing whether tmp is nonzero. */ | |
1113 | ||
1114 | while (n >= sizeof (longword)) | |
1115 | { | |
1116 | longword longword1 = *--longword_ptr ^ repeated_c; | |
1117 | ||
1118 | if ((((longword1 - repeated_one) & ~longword1) | |
1119 | & (repeated_one << 7)) != 0) | |
1120 | { | |
1121 | longword_ptr++; | |
1122 | break; | |
1123 | } | |
1124 | n -= sizeof (longword); | |
1125 | } | |
1126 | ||
1127 | char_ptr = (const unsigned char *) longword_ptr; | |
1128 | ||
1129 | /* At this point, we know that either n < sizeof (longword), or one of the | |
1130 | sizeof (longword) bytes starting at char_ptr is == c. On little-endian | |
1131 | machines, we could determine the first such byte without any further | |
1132 | memory accesses, just by looking at the tmp result from the last loop | |
1133 | iteration. But this does not work on big-endian machines. Choose code | |
1134 | that works in both cases. */ | |
1135 | ||
1136 | while (n-- > 0) | |
1137 | { | |
1138 | if (*--char_ptr == c) | |
1139 | return (void *) char_ptr; | |
1140 | } | |
1141 | ||
1142 | return NULL; | |
1143 | } | |
1144 | #ifdef weak_alias | |
1145 | weak_alias (__memrchr, memrchr) | |
1146 | #endif |