git.sesse.net Git - plocate/blob - plocate.cpp

   1 #include "db.h"
   2 #include "io_uring_engine.h"
   3 #include "parse_trigrams.h"
   4 #include "turbopfor.h"
   5 #include "unique_sort.h"
   6
   7 #include <algorithm>
   8 #include <assert.h>
   9 #include <chrono>
  10 #include <fcntl.h>
  11 #include <fnmatch.h>
  12 #include <functional>
  13 #include <getopt.h>
  14 #include <iosfwd>
  15 #include <iterator>
  16 #include <limits>
  17 #include <memory>
  18 #include <queue>
  19 #include <regex.h>
  20 #include <stdint.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <string>
  25 #include <string_view>
  26 #include <unistd.h>
  27 #include <unordered_map>
  28 #include <unordered_set>
  29 #include <utility>
  30 #include <vector>
  31 #include <zstd.h>
  32
  33 using namespace std;
  34 using namespace std::chrono;
  35
  36 #define dprintf(...) \
  37         do { \
  38                 if (use_debug) { \
  39                         fprintf(stderr, __VA_ARGS__); \
  40                 } \
  41         } while (false)
  42
  43 #define DEFAULT_DBPATH "/var/lib/mlocate/plocate.db"
  44
  45 const char *dbpath = DEFAULT_DBPATH;
  46 bool ignore_case = false;
  47 bool only_count = false;
  48 bool print_nul = false;
  49 bool use_debug = false;
  50 int64_t limit_matches = numeric_limits<int64_t>::max();
  51
  52 class Serializer {
  53 public:
  54         bool ready_to_print(int seq) { return next_seq == seq; }
  55         void print_delayed(int seq, const vector<string> msg);
  56         void release_current();
  57
  58 private:
  59         int next_seq = 0;
  60         struct Element {
  61                 int seq;
  62                 vector<string> msg;
  63
  64                 bool operator<(const Element &other) const
  65                 {
  66                         return seq > other.seq;
  67                 }
  68         };
  69         priority_queue<Element> pending;
  70 };
  71
  72 void Serializer::print_delayed(int seq, const vector<string> msg)
  73 {
  74         pending.push(Element{ seq, move(msg) });
  75 }
  76
  77 void Serializer::release_current()
  78 {
  79         ++next_seq;
  80
  81         // See if any delayed prints can now be dealt with.
  82         while (!pending.empty() && pending.top().seq == next_seq) {
  83                 if (limit_matches-- <= 0)
  84                         return;
  85                 for (const string &msg : pending.top().msg) {
  86                         if (print_nul) {
  87                                 printf("%s%c", msg.c_str(), 0);
  88                         } else {
  89                                 printf("%s\n", msg.c_str());
  90                         }
  91                 }
  92                 pending.pop();
  93                 ++next_seq;
  94         }
  95 }
  96
  97 struct Needle {
  98         enum { STRSTR,
  99                REGEX,  // Not currently used.
 100                GLOB } type;
 101         string str;  // Filled in no matter what.
 102         regex_t re;  // For REGEX.
 103 };
 104
 105 bool matches(const Needle &needle, const char *haystack)
 106 {
 107         if (needle.type == Needle::STRSTR) {
 108                 return strstr(haystack, needle.str.c_str()) != nullptr;
 109         } else if (needle.type == Needle::GLOB) {
 110                 int flags = ignore_case ? FNM_CASEFOLD : 0;
 111                 return fnmatch(needle.str.c_str(), haystack, flags) == 0;
 112         } else {
 113                 assert(needle.type == Needle::REGEX);
 114                 return regexec(&needle.re, haystack, /*nmatch=*/0, /*pmatch=*/nullptr, /*flags=*/0) == 0;
 115         }
 116 }
 117
 118 bool has_access(const char *filename,
 119                 unordered_map<string, bool> *access_rx_cache)
 120 {
 121         const char *end = strchr(filename + 1, '/');
 122         while (end != nullptr) {
 123                 string parent_path(filename, end);
 124                 auto it = access_rx_cache->find(parent_path);
 125                 bool ok;
 126                 if (it == access_rx_cache->end()) {
 127                         ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
 128                         access_rx_cache->emplace(move(parent_path), ok);
 129                 } else {
 130                         ok = it->second;
 131                 }
 132                 if (!ok) {
 133                         return false;
 134                 }
 135                 end = strchr(end + 1, '/');
 136         }
 137
 138         return true;
 139 }
 140
 141 class Corpus {
 142 public:
 143         Corpus(int fd, IOUringEngine *engine);
 144         ~Corpus();
 145         void find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb);
 146         void get_compressed_filename_block(uint32_t docid, function<void(string_view)> cb) const;
 147         size_t get_num_filename_blocks() const;
 148         off_t offset_for_block(uint32_t docid) const
 149         {
 150                 return hdr.filename_index_offset_bytes + docid * sizeof(uint64_t);
 151         }
 152
 153 public:
 154         const int fd;
 155         IOUringEngine *const engine;
 156
 157         Header hdr;
 158 };
 159
 160 Corpus::Corpus(int fd, IOUringEngine *engine)
 161         : fd(fd), engine(engine)
 162 {
 163         // Enable to test cold-cache behavior (except for access()).
 164         if (false) {
 165                 off_t len = lseek(fd, 0, SEEK_END);
 166                 if (len == -1) {
 167                         perror("lseek");
 168                         exit(1);
 169                 }
 170                 posix_fadvise(fd, 0, len, POSIX_FADV_DONTNEED);
 171         }
 172
 173         complete_pread(fd, &hdr, sizeof(hdr), /*offset=*/0);
 174         if (memcmp(hdr.magic, "\0plocate", 8) != 0) {
 175                 fprintf(stderr, "plocate.db is corrupt or an old version; please rebuild it.\n");
 176                 exit(1);
 177         }
 178         if (hdr.version != 0) {
 179                 fprintf(stderr, "plocate.db has version %u, expected 0; please rebuild it.\n", hdr.version);
 180                 exit(1);
 181         }
 182 }
 183
 184 Corpus::~Corpus()
 185 {
 186         close(fd);
 187 }
 188
 189 void Corpus::find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb)
 190 {
 191         uint32_t bucket = hash_trigram(trgm, hdr.hashtable_size);
 192         engine->submit_read(fd, sizeof(Trigram) * (hdr.extra_ht_slots + 2), hdr.hash_table_offset_bytes + sizeof(Trigram) * bucket, [this, trgm, cb{ move(cb) }](string_view s) {
 193                 const Trigram *trgmptr = reinterpret_cast<const Trigram *>(s.data());
 194                 for (unsigned i = 0; i < hdr.extra_ht_slots + 1; ++i) {
 195                         if (trgmptr[i].trgm == trgm) {
 196                                 cb(trgmptr + i, trgmptr[i + 1].offset - trgmptr[i].offset);
 197                                 return;
 198                         }
 199                 }
 200
 201                 // Not found.
 202                 cb(nullptr, 0);
 203         });
 204 }
 205
 206 void Corpus::get_compressed_filename_block(uint32_t docid, function<void(string_view)> cb) const
 207 {
 208         // Read the file offset from this docid and the next one.
 209         // This is always allowed, since we have a sentinel block at the end.
 210         engine->submit_read(fd, sizeof(uint64_t) * 2, offset_for_block(docid), [this, cb{ move(cb) }](string_view s) {
 211                 const uint64_t *ptr = reinterpret_cast<const uint64_t *>(s.data());
 212                 off_t offset = ptr[0];
 213                 size_t len = ptr[1] - ptr[0];
 214                 engine->submit_read(fd, len, offset, cb);
 215         });
 216 }
 217
 218 size_t Corpus::get_num_filename_blocks() const
 219 {
 220         return hdr.num_docids;
 221 }
 222
 223 uint64_t scan_file_block(const vector<Needle> &needles, string_view compressed,
 224                          unordered_map<string, bool> *access_rx_cache, int seq,
 225                          Serializer *serializer)
 226 {
 227         uint64_t matched = 0;
 228
 229         unsigned long long uncompressed_len = ZSTD_getFrameContentSize(compressed.data(), compressed.size());
 230         if (uncompressed_len == ZSTD_CONTENTSIZE_UNKNOWN || uncompressed_len == ZSTD_CONTENTSIZE_ERROR) {
 231                 fprintf(stderr, "ZSTD_getFrameContentSize() failed\n");
 232                 exit(1);
 233         }
 234
 235         string block;
 236         block.resize(uncompressed_len + 1);
 237
 238         size_t err = ZSTD_decompress(&block[0], block.size(), compressed.data(),
 239                                      compressed.size());
 240         if (ZSTD_isError(err)) {
 241                 fprintf(stderr, "ZSTD_decompress(): %s\n", ZSTD_getErrorName(err));
 242                 exit(1);
 243         }
 244         block[block.size() - 1] = '\0';
 245
 246         bool immediate_print = (serializer == nullptr || serializer->ready_to_print(seq));
 247         vector<string> delayed;
 248
 249         for (const char *filename = block.data();
 250              filename != block.data() + block.size();
 251              filename += strlen(filename) + 1) {
 252                 bool found = true;
 253                 for (const Needle &needle : needles) {
 254                         if (!matches(needle, filename)) {
 255                                 found = false;
 256                                 break;
 257                         }
 258                 }
 259                 if (found && has_access(filename, access_rx_cache)) {
 260                         if (limit_matches-- <= 0)
 261                                 break;
 262                         ++matched;
 263                         if (only_count)
 264                                 continue;
 265                         if (immediate_print) {
 266                                 if (print_nul) {
 267                                         printf("%s%c", filename, 0);
 268                                 } else {
 269                                         printf("%s\n", filename);
 270                                 }
 271                         } else {
 272                                 delayed.push_back(filename);
 273                         }
 274                 }
 275         }
 276         if (serializer != nullptr && !only_count) {
 277                 if (immediate_print) {
 278                         serializer->release_current();
 279                 } else {
 280                         serializer->print_delayed(seq, move(delayed));
 281                 }
 282         }
 283         return matched;
 284 }
 285
 286 size_t scan_docids(const vector<Needle> &needles, const vector<uint32_t> &docids, const Corpus &corpus, IOUringEngine *engine)
 287 {
 288         Serializer docids_in_order;
 289         unordered_map<string, bool> access_rx_cache;
 290         uint64_t matched = 0;
 291         for (size_t i = 0; i < docids.size(); ++i) {
 292                 uint32_t docid = docids[i];
 293                 corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, &docids_in_order](string_view compressed) {
 294                         matched += scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order);
 295                 });
 296         }
 297         engine->finish();
 298         return matched;
 299 }
 300
 301 // We do this sequentially, as it's faster than scattering
 302 // a lot of I/O through io_uring and hoping the kernel will
 303 // coalesce it plus readahead for us.
 304 uint64_t scan_all_docids(const vector<Needle> &needles, int fd, const Corpus &corpus, IOUringEngine *engine)
 305 {
 306         unordered_map<string, bool> access_rx_cache;
 307         uint32_t num_blocks = corpus.get_num_filename_blocks();
 308         unique_ptr<uint64_t[]> offsets(new uint64_t[num_blocks + 1]);
 309         complete_pread(fd, offsets.get(), (num_blocks + 1) * sizeof(uint64_t), corpus.offset_for_block(0));
 310         string compressed;
 311         uint64_t matched = 0;
 312         for (uint32_t io_docid = 0; io_docid < num_blocks; io_docid += 32) {
 313                 uint32_t last_docid = std::min(io_docid + 32, num_blocks);
 314                 size_t io_len = offsets[last_docid] - offsets[io_docid];
 315                 if (compressed.size() < io_len) {
 316                         compressed.resize(io_len);
 317                 }
 318                 complete_pread(fd, &compressed[0], io_len, offsets[io_docid]);
 319
 320                 for (uint32_t docid = io_docid; docid < last_docid; ++docid) {
 321                         size_t relative_offset = offsets[docid] - offsets[io_docid];
 322                         size_t len = offsets[docid + 1] - offsets[docid];
 323                         matched += scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, 0, nullptr);
 324                         if (limit_matches <= 0)
 325                                 return matched;
 326                 }
 327         }
 328         return matched;
 329 }
 330
 331 // Takes the given posting list, unions it into the parts of the trigram disjunction
 332 // already read; if the list is complete, intersects with “cur_candidates”.
 333 //
 334 // Returns true if the search should be aborted (we are done).
 335 bool new_posting_list_read(TrigramDisjunction *td, vector<uint32_t> decoded, vector<uint32_t> *cur_candidates, vector<uint32_t> *tmp)
 336 {
 337         if (td->docids.empty()) {
 338                 td->docids = move(decoded);
 339         } else {
 340                 tmp->clear();
 341                 set_union(decoded.begin(), decoded.end(), td->docids.begin(), td->docids.end(), back_inserter(*tmp));
 342                 swap(*tmp, td->docids);
 343         }
 344         if (--td->remaining_trigrams_to_read > 0) {
 345                 // Need to wait for more.
 346                 if (ignore_case) {
 347                         dprintf("  ... %u reads left in OR group %u (%zu docids in list)\n",
 348                                 td->remaining_trigrams_to_read, td->index, td->docids.size());
 349                 }
 350                 return false;
 351         }
 352         if (cur_candidates->empty()) {
 353                 if (ignore_case) {
 354                         dprintf("  ... all reads done for OR group %u (%zu docids)\n",
 355                                 td->index, td->docids.size());
 356                 }
 357                 *cur_candidates = move(td->docids);
 358         } else {
 359                 tmp->clear();
 360                 set_intersection(cur_candidates->begin(), cur_candidates->end(),
 361                                  td->docids.begin(), td->docids.end(),
 362                                  back_inserter(*tmp));
 363                 swap(*cur_candidates, *tmp);
 364                 if (ignore_case) {
 365                         if (cur_candidates->empty()) {
 366                                 dprintf("  ... all reads done for OR group %u (%zu docids), intersected (none left, search is done)\n",
 367                                         td->index, td->docids.size());
 368                                 return true;
 369                         } else {
 370                                 dprintf("  ... all reads done for OR group %u (%zu docids), intersected (%zu left)\n",
 371                                         td->index, td->docids.size(), cur_candidates->size());
 372                         }
 373                 }
 374         }
 375         return false;
 376 }
 377
 378 void do_search_file(const vector<Needle> &needles, const char *filename)
 379 {
 380         int fd = open(filename, O_RDONLY);
 381         if (fd == -1) {
 382                 perror(filename);
 383                 exit(1);
 384         }
 385
 386         // Drop privileges.
 387         if (setgid(getgid()) != 0) {
 388                 perror("setgid");
 389                 exit(EXIT_FAILURE);
 390         }
 391
 392         steady_clock::time_point start __attribute__((unused)) = steady_clock::now();
 393         if (access("/", R_OK | X_OK)) {
 394                 // We can't find anything, no need to bother...
 395                 return;
 396         }
 397
 398         IOUringEngine engine(/*slop_bytes=*/16);  // 16 slop bytes as described in turbopfor.h.
 399         Corpus corpus(fd, &engine);
 400         dprintf("Corpus init done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
 401
 402         vector<TrigramDisjunction> trigram_groups;
 403         for (const Needle &needle : needles) {
 404                 if (needle.str.size() < 3)
 405                         continue;
 406                 parse_trigrams(needle.str, ignore_case, &trigram_groups);
 407         }
 408         unique_sort(
 409                 &trigram_groups,
 410                 [](const TrigramDisjunction &a, const TrigramDisjunction &b) { return a.trigram_alternatives < b.trigram_alternatives; },
 411                 [](const TrigramDisjunction &a, const TrigramDisjunction &b) { return a.trigram_alternatives == b.trigram_alternatives; });
 412
 413         // Give them names for debugging.
 414         unsigned td_index = 0;
 415         for (TrigramDisjunction &td : trigram_groups) {
 416                 td.index = td_index++;
 417         }
 418
 419         // Collect which trigrams we need to look up in the hash table.
 420         unordered_map<uint32_t, vector<TrigramDisjunction *>> trigrams_to_lookup;
 421         for (TrigramDisjunction &td : trigram_groups) {
 422                 for (uint32_t trgm : td.trigram_alternatives) {
 423                         trigrams_to_lookup[trgm].push_back(&td);
 424                 }
 425         }
 426         if (trigrams_to_lookup.empty()) {
 427                 // Too short for trigram matching. Apply brute force.
 428                 // (We could have searched through all trigrams that matched
 429                 // the pattern and done a union of them, but that's a lot of
 430                 // work for fairly unclear gain.)
 431                 uint64_t matched = scan_all_docids(needles, fd, corpus, &engine);
 432                 if (only_count) {
 433                         printf("%zu\n", matched);
 434                 }
 435                 return;
 436         }
 437
 438         // Look them all up on disk.
 439         for (auto &[trgm, trigram_groups] : trigrams_to_lookup) {
 440                 corpus.find_trigram(trgm, [trgm{ trgm }, trigram_groups{ &trigram_groups }](const Trigram *trgmptr, size_t len) {
 441                         if (trgmptr == nullptr) {
 442                                 dprintf("trigram %s isn't found\n", print_trigram(trgm).c_str());
 443                                 for (TrigramDisjunction *td : *trigram_groups) {
 444                                         --td->remaining_trigrams_to_read;
 445                                         if (td->remaining_trigrams_to_read == 0 && td->read_trigrams.empty()) {
 446                                                 dprintf("zero matches in %s, so we are done\n", print_td(*td).c_str());
 447                                                 if (only_count) {
 448                                                         printf("0\n");
 449                                                 }
 450                                                 exit(0);
 451                                         }
 452                                 }
 453                                 return;
 454                         }
 455                         for (TrigramDisjunction *td : *trigram_groups) {
 456                                 --td->remaining_trigrams_to_read;
 457                                 td->max_num_docids += trgmptr->num_docids;
 458                                 td->read_trigrams.emplace_back(*trgmptr, len);
 459                         }
 460                 });
 461         }
 462         engine.finish();
 463         dprintf("Hashtable lookups done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
 464
 465         for (TrigramDisjunction &td : trigram_groups) {
 466                 // Reset for reads.
 467                 td.remaining_trigrams_to_read = td.read_trigrams.size();
 468
 469                 if (ignore_case) {  // If case-sensitive, they'll all be pretty obvious single-entry groups.
 470                         dprintf("OR group %u (max_num_docids=%u): %s\n", td.index, td.max_num_docids, print_td(td).c_str());
 471                 }
 472         }
 473
 474         // TODO: For case-insensitive (ie. more than one alternative in each),
 475         // prioritize the ones with fewer seeks?
 476         sort(trigram_groups.begin(), trigram_groups.end(),
 477              [&](const TrigramDisjunction &a, const TrigramDisjunction &b) {
 478                      return a.max_num_docids < b.max_num_docids;
 479              });
 480
 481         unordered_map<uint32_t, vector<TrigramDisjunction *>> uses_trigram;
 482         for (TrigramDisjunction &td : trigram_groups) {
 483                 for (uint32_t trgm : td.trigram_alternatives) {
 484                         uses_trigram[trgm].push_back(&td);
 485                 }
 486         }
 487
 488         unordered_set<uint32_t> trigrams_submitted_read;
 489         vector<uint32_t> cur_candidates, tmp, decoded;
 490         bool done = false;
 491         for (TrigramDisjunction &td : trigram_groups) {
 492                 if (!cur_candidates.empty() && td.max_num_docids > cur_candidates.size() * 100) {
 493                         dprintf("%s has up to %u entries, ignoring the rest (will "
 494                                 "weed out false positives later)\n",
 495                                 print_td(td).c_str(), td.max_num_docids);
 496                         break;
 497                 }
 498
 499                 for (auto &[trgmptr, len] : td.read_trigrams) {
 500                         if (trigrams_submitted_read.count(trgmptr.trgm) != 0) {
 501                                 continue;
 502                         }
 503                         trigrams_submitted_read.insert(trgmptr.trgm);
 504                         // Only stay a certain amount ahead, so that we don't spend I/O
 505                         // on reading the latter, large posting lists. We are unlikely
 506                         // to need them anyway, even if they should come in first.
 507                         if (engine.get_waiting_reads() >= 5) {
 508                                 engine.finish();
 509                                 if (done)
 510                                         break;
 511                         }
 512                         engine.submit_read(fd, len, trgmptr.offset, [trgmptr{ trgmptr }, len{ len }, &done, &cur_candidates, &tmp, &decoded, &uses_trigram](string_view s) {
 513                                 if (done)
 514                                         return;
 515
 516                                 uint32_t trgm __attribute__((unused)) = trgmptr.trgm;
 517                                 const unsigned char *pldata = reinterpret_cast<const unsigned char *>(s.data());
 518                                 size_t num = trgmptr.num_docids;
 519                                 decoded.resize(num);
 520                                 decode_pfor_delta1_128(pldata, num, /*interleaved=*/true, &decoded[0]);
 521
 522                                 assert(uses_trigram.count(trgm) != 0);
 523                                 bool was_empty = cur_candidates.empty();
 524                                 if (ignore_case) {
 525                                         dprintf("trigram %s (%zu bytes) decoded to %zu entries\n", print_trigram(trgm).c_str(), len, num);
 526                                 }
 527
 528                                 for (TrigramDisjunction *td : uses_trigram[trgm]) {
 529                                         done |= new_posting_list_read(td, decoded, &cur_candidates, &tmp);
 530                                         if (done)
 531                                                 break;
 532                                 }
 533                                 if (!ignore_case) {
 534                                         if (was_empty) {
 535                                                 dprintf("trigram %s (%zu bytes) decoded to %zu entries\n", print_trigram(trgm).c_str(), len, num);
 536                                         } else if (cur_candidates.empty()) {
 537                                                 dprintf("trigram %s (%zu bytes) decoded to %zu entries (none left, search is done)\n", print_trigram(trgm).c_str(), len, num);
 538                                         } else {
 539                                                 dprintf("trigram %s (%zu bytes) decoded to %zu entries (%zu left)\n", print_trigram(trgm).c_str(), len, num, cur_candidates.size());
 540                                         }
 541                                 }
 542                         });
 543                 }
 544         }
 545         engine.finish();
 546         if (done) {
 547                 return;
 548         }
 549         dprintf("Intersection done after %.1f ms. Doing final verification and printing:\n",
 550                 1e3 * duration<float>(steady_clock::now() - start).count());
 551
 552         uint64_t matched = scan_docids(needles, cur_candidates, corpus, &engine);
 553         dprintf("Done in %.1f ms, found %zu matches.\n",
 554                 1e3 * duration<float>(steady_clock::now() - start).count(), matched);
 555
 556         if (only_count) {
 557                 printf("%zu\n", matched);
 558         }
 559 }
 560
 561 string unescape_glob_to_plain_string(const string &needle)
 562 {
 563         string unescaped;
 564         for (size_t i = 0; i < needle.size(); i += read_unigram(needle, i).second) {
 565                 uint32_t ch = read_unigram(needle, i).first;
 566                 assert(ch != WILDCARD_UNIGRAM);
 567                 if (ch == PREMATURE_END_UNIGRAM) {
 568                         fprintf(stderr, "Pattern '%s' ended prematurely\n", needle.c_str());
 569                         exit(1);
 570                 }
 571                 unescaped.push_back(ch);
 572         }
 573         return unescaped;
 574 }
 575
 576 void usage()
 577 {
 578         printf(
 579                 "Usage: plocate [OPTION]... PATTERN...\n"
 580                 "\n"
 581                 "  -c, --count            print number of matches instead of the matches\n"
 582                 "  -d, --database DBPATH  search for files in DBPATH\n"
 583                 "                         (default is " DEFAULT_DBPATH ")\n"
 584                 "  -i, --ignore-case      search case-insensitively\n"
 585                 "  -l, --limit LIMIT      stop after LIMIT matches\n"
 586                 "  -0, --null             delimit matches by NUL instead of newline\n"
 587                 "      --help             print this help\n"
 588                 "      --version          print version information\n");
 589 }
 590
 591 void version()
 592 {
 593         printf("plocate %s\n", PLOCATE_VERSION);
 594         printf("Copyright 2020 Steinar H. Gunderson\n");
 595         printf("License GPLv2+: GNU GPL version 2 or later <https://gnu.org/licenses/gpl.html>.\n");
 596         printf("This is free software: you are free to change and redistribute it.\n");
 597         printf("There is NO WARRANTY, to the extent permitted by law.\n");
 598         exit(0);
 599 }
 600
 601 int main(int argc, char **argv)
 602 {
 603         static const struct option long_options[] = {
 604                 { "help", no_argument, 0, 'h' },
 605                 { "count", no_argument, 0, 'c' },
 606                 { "database", required_argument, 0, 'd' },
 607                 { "ignore-case", no_argument, 0, 'i' },
 608                 { "limit", required_argument, 0, 'l' },
 609                 { "null", no_argument, 0, '0' },
 610                 { "version", no_argument, 0, 'V' },
 611                 { "debug", no_argument, 0, 'D' },  // Not documented.
 612                 { 0, 0, 0, 0 }
 613         };
 614
 615         setlocale(LC_ALL, "");
 616         for (;;) {
 617                 int option_index = 0;
 618                 int c = getopt_long(argc, argv, "cd:hil:n:0VD", long_options, &option_index);
 619                 if (c == -1) {
 620                         break;
 621                 }
 622                 switch (c) {
 623                 case 'c':
 624                         only_count = true;
 625                         break;
 626                 case 'd':
 627                         dbpath = strdup(optarg);
 628                         break;
 629                 case 'h':
 630                         usage();
 631                         exit(0);
 632                 case 'i':
 633                         ignore_case = true;
 634                         break;
 635                 case 'l':
 636                 case 'n':
 637                         limit_matches = atoll(optarg);
 638                         break;
 639                 case '0':
 640                         print_nul = true;
 641                         break;
 642                 case 'D':
 643                         use_debug = true;
 644                         break;
 645                 case 'V':
 646                         version();
 647                         break;
 648                 default:
 649                         exit(1);
 650                 }
 651         }
 652
 653         if (use_debug) {
 654                 // Debug information would leak information about which files exist,
 655                 // so drop setgid before we open the file; one would either need to run
 656                 // as root, or use a locally-built file.
 657                 if (setgid(getgid()) != 0) {
 658                         perror("setgid");
 659                         exit(EXIT_FAILURE);
 660                 }
 661         }
 662
 663         vector<Needle> needles;
 664         for (int i = optind; i < argc; ++i) {
 665                 Needle needle;
 666                 needle.str = argv[i];
 667
 668                 // See if there are any wildcard characters, which indicates we should treat it
 669                 // as an (anchored) glob.
 670                 bool any_wildcard = false;
 671                 for (size_t i = 0; i < needle.str.size(); i += read_unigram(needle.str, i).second) {
 672                         if (read_unigram(needle.str, i).first == WILDCARD_UNIGRAM) {
 673                                 any_wildcard = true;
 674                                 break;
 675                         }
 676                 }
 677
 678                 if (any_wildcard) {
 679                         needle.type = Needle::GLOB;
 680                 } else if (ignore_case) {
 681                         // strcasestr() doesn't handle locales correctly (even though LSB
 682                         // claims it should), but somehow, fnmatch() does, and it's about
 683                         // the same speed as using a regex.
 684                         needle.type = Needle::GLOB;
 685                         needle.str = "*" + needle.str + "*";
 686                 } else {
 687                         needle.type = Needle::STRSTR;
 688                         needle.str = unescape_glob_to_plain_string(needle.str);
 689                 }
 690                 needles.push_back(move(needle));
 691         }
 692         if (needles.empty()) {
 693                 fprintf(stderr, "plocate: no pattern to search for specified\n");
 694                 exit(0);
 695         }
 696         do_search_file(needles, dbpath);
 697 }