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

   1 #include "db.h"
   2 #include "dprintf.h"
   3 #include "io_uring_engine.h"
   4 #include "parse_trigrams.h"
   5 #include "turbopfor.h"
   6 #include "unique_sort.h"
   7
   8 #include <algorithm>
   9 #include <assert.h>
  10 #include <chrono>
  11 #include <fcntl.h>
  12 #include <fnmatch.h>
  13 #include <functional>
  14 #include <getopt.h>
  15 #include <iosfwd>
  16 #include <iterator>
  17 #include <limits>
  18 #include <memory>
  19 #include <queue>
  20 #include <regex.h>
  21 #include <stdint.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <string>
  26 #include <string_view>
  27 #include <unistd.h>
  28 #include <unordered_map>
  29 #include <unordered_set>
  30 #include <utility>
  31 #include <vector>
  32 #include <zstd.h>
  33
  34 using namespace std;
  35 using namespace std::chrono;
  36
  37 #define DEFAULT_DBPATH "/var/lib/mlocate/plocate.db"
  38
  39 const char *dbpath = DEFAULT_DBPATH;
  40 bool ignore_case = false;
  41 bool only_count = false;
  42 bool print_nul = false;
  43 bool use_debug = false;
  44 bool patterns_are_regex = false;
  45 bool use_extended_regex = false;
  46 int64_t limit_matches = numeric_limits<int64_t>::max();
  47
  48 class Serializer {
  49 public:
  50         bool ready_to_print(int seq) { return next_seq == seq; }
  51         void print_delayed(int seq, const vector<string> msg);
  52         void release_current();
  53
  54 private:
  55         int next_seq = 0;
  56         struct Element {
  57                 int seq;
  58                 vector<string> msg;
  59
  60                 bool operator<(const Element &other) const
  61                 {
  62                         return seq > other.seq;
  63                 }
  64         };
  65         priority_queue<Element> pending;
  66 };
  67
  68 void Serializer::print_delayed(int seq, const vector<string> msg)
  69 {
  70         pending.push(Element{ seq, move(msg) });
  71 }
  72
  73 void Serializer::release_current()
  74 {
  75         ++next_seq;
  76
  77         // See if any delayed prints can now be dealt with.
  78         while (!pending.empty() && pending.top().seq == next_seq) {
  79                 if (limit_matches-- <= 0)
  80                         return;
  81                 for (const string &msg : pending.top().msg) {
  82                         if (print_nul) {
  83                                 printf("%s%c", msg.c_str(), 0);
  84                         } else {
  85                                 printf("%s\n", msg.c_str());
  86                         }
  87                 }
  88                 pending.pop();
  89                 ++next_seq;
  90         }
  91 }
  92
  93 struct Needle {
  94         enum { STRSTR,
  95                REGEX,
  96                GLOB } type;
  97         string str;  // Filled in no matter what.
  98         regex_t re;  // For REGEX.
  99 };
 100
 101 bool matches(const Needle &needle, const char *haystack)
 102 {
 103         if (needle.type == Needle::STRSTR) {
 104                 return strstr(haystack, needle.str.c_str()) != nullptr;
 105         } else if (needle.type == Needle::GLOB) {
 106                 int flags = ignore_case ? FNM_CASEFOLD : 0;
 107                 return fnmatch(needle.str.c_str(), haystack, flags) == 0;
 108         } else {
 109                 assert(needle.type == Needle::REGEX);
 110                 return regexec(&needle.re, haystack, /*nmatch=*/0, /*pmatch=*/nullptr, /*flags=*/0) == 0;
 111         }
 112 }
 113
 114 bool has_access(const char *filename,
 115                 unordered_map<string, bool> *access_rx_cache)
 116 {
 117         const char *end = strchr(filename + 1, '/');
 118         while (end != nullptr) {
 119                 string parent_path(filename, end);
 120                 auto it = access_rx_cache->find(parent_path);
 121                 bool ok;
 122                 if (it == access_rx_cache->end()) {
 123                         ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
 124                         access_rx_cache->emplace(move(parent_path), ok);
 125                 } else {
 126                         ok = it->second;
 127                 }
 128                 if (!ok) {
 129                         return false;
 130                 }
 131                 end = strchr(end + 1, '/');
 132         }
 133
 134         return true;
 135 }
 136
 137 class Corpus {
 138 public:
 139         Corpus(int fd, IOUringEngine *engine);
 140         ~Corpus();
 141         void find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb);
 142         void get_compressed_filename_block(uint32_t docid, function<void(string_view)> cb) const;
 143         size_t get_num_filename_blocks() const;
 144         off_t offset_for_block(uint32_t docid) const
 145         {
 146                 return hdr.filename_index_offset_bytes + docid * sizeof(uint64_t);
 147         }
 148
 149 public:
 150         const int fd;
 151         IOUringEngine *const engine;
 152
 153         Header hdr;
 154 };
 155
 156 Corpus::Corpus(int fd, IOUringEngine *engine)
 157         : fd(fd), engine(engine)
 158 {
 159         // Enable to test cold-cache behavior (except for access()).
 160         if (false) {
 161                 off_t len = lseek(fd, 0, SEEK_END);
 162                 if (len == -1) {
 163                         perror("lseek");
 164                         exit(1);
 165                 }
 166                 posix_fadvise(fd, 0, len, POSIX_FADV_DONTNEED);
 167         }
 168
 169         complete_pread(fd, &hdr, sizeof(hdr), /*offset=*/0);
 170         if (memcmp(hdr.magic, "\0plocate", 8) != 0) {
 171                 fprintf(stderr, "plocate.db is corrupt or an old version; please rebuild it.\n");
 172                 exit(1);
 173         }
 174         if (hdr.version != 0) {
 175                 fprintf(stderr, "plocate.db has version %u, expected 0; please rebuild it.\n", hdr.version);
 176                 exit(1);
 177         }
 178 }
 179
 180 Corpus::~Corpus()
 181 {
 182         close(fd);
 183 }
 184
 185 void Corpus::find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb)
 186 {
 187         uint32_t bucket = hash_trigram(trgm, hdr.hashtable_size);
 188         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) {
 189                 const Trigram *trgmptr = reinterpret_cast<const Trigram *>(s.data());
 190                 for (unsigned i = 0; i < hdr.extra_ht_slots + 1; ++i) {
 191                         if (trgmptr[i].trgm == trgm) {
 192                                 cb(trgmptr + i, trgmptr[i + 1].offset - trgmptr[i].offset);
 193                                 return;
 194                         }
 195                 }
 196
 197                 // Not found.
 198                 cb(nullptr, 0);
 199         });
 200 }
 201
 202 void Corpus::get_compressed_filename_block(uint32_t docid, function<void(string_view)> cb) const
 203 {
 204         // Read the file offset from this docid and the next one.
 205         // This is always allowed, since we have a sentinel block at the end.
 206         engine->submit_read(fd, sizeof(uint64_t) * 2, offset_for_block(docid), [this, cb{ move(cb) }](string_view s) {
 207                 const uint64_t *ptr = reinterpret_cast<const uint64_t *>(s.data());
 208                 off_t offset = ptr[0];
 209                 size_t len = ptr[1] - ptr[0];
 210                 engine->submit_read(fd, len, offset, cb);
 211         });
 212 }
 213
 214 size_t Corpus::get_num_filename_blocks() const
 215 {
 216         return hdr.num_docids;
 217 }
 218
 219 uint64_t scan_file_block(const vector<Needle> &needles, string_view compressed,
 220                          unordered_map<string, bool> *access_rx_cache, int seq,
 221                          Serializer *serializer)
 222 {
 223         uint64_t matched = 0;
 224
 225         unsigned long long uncompressed_len = ZSTD_getFrameContentSize(compressed.data(), compressed.size());
 226         if (uncompressed_len == ZSTD_CONTENTSIZE_UNKNOWN || uncompressed_len == ZSTD_CONTENTSIZE_ERROR) {
 227                 fprintf(stderr, "ZSTD_getFrameContentSize() failed\n");
 228                 exit(1);
 229         }
 230
 231         string block;
 232         block.resize(uncompressed_len + 1);
 233
 234         size_t err = ZSTD_decompress(&block[0], block.size(), compressed.data(),
 235                                      compressed.size());
 236         if (ZSTD_isError(err)) {
 237                 fprintf(stderr, "ZSTD_decompress(): %s\n", ZSTD_getErrorName(err));
 238                 exit(1);
 239         }
 240         block[block.size() - 1] = '\0';
 241
 242         bool immediate_print = (serializer == nullptr || serializer->ready_to_print(seq));
 243         vector<string> delayed;
 244
 245         for (const char *filename = block.data();
 246              filename != block.data() + block.size();
 247              filename += strlen(filename) + 1) {
 248                 bool found = true;
 249                 for (const Needle &needle : needles) {
 250                         if (!matches(needle, filename)) {
 251                                 found = false;
 252                                 break;
 253                         }
 254                 }
 255                 if (found && has_access(filename, access_rx_cache)) {
 256                         if (limit_matches-- <= 0)
 257                                 break;
 258                         ++matched;
 259                         if (only_count)
 260                                 continue;
 261                         if (immediate_print) {
 262                                 if (print_nul) {
 263                                         printf("%s%c", filename, 0);
 264                                 } else {
 265                                         printf("%s\n", filename);
 266                                 }
 267                         } else {
 268                                 delayed.push_back(filename);
 269                         }
 270                 }
 271         }
 272         if (serializer != nullptr && !only_count) {
 273                 if (immediate_print) {
 274                         serializer->release_current();
 275                 } else {
 276                         serializer->print_delayed(seq, move(delayed));
 277                 }
 278         }
 279         return matched;
 280 }
 281
 282 size_t scan_docids(const vector<Needle> &needles, const vector<uint32_t> &docids, const Corpus &corpus, IOUringEngine *engine)
 283 {
 284         Serializer docids_in_order;
 285         unordered_map<string, bool> access_rx_cache;
 286         uint64_t matched = 0;
 287         for (size_t i = 0; i < docids.size(); ++i) {
 288                 uint32_t docid = docids[i];
 289                 corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, &docids_in_order](string_view compressed) {
 290                         matched += scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order);
 291                 });
 292         }
 293         engine->finish();
 294         return matched;
 295 }
 296
 297 // We do this sequentially, as it's faster than scattering
 298 // a lot of I/O through io_uring and hoping the kernel will
 299 // coalesce it plus readahead for us.
 300 uint64_t scan_all_docids(const vector<Needle> &needles, int fd, const Corpus &corpus, IOUringEngine *engine)
 301 {
 302         unordered_map<string, bool> access_rx_cache;
 303         uint32_t num_blocks = corpus.get_num_filename_blocks();
 304         unique_ptr<uint64_t[]> offsets(new uint64_t[num_blocks + 1]);
 305         complete_pread(fd, offsets.get(), (num_blocks + 1) * sizeof(uint64_t), corpus.offset_for_block(0));
 306         string compressed;
 307         uint64_t matched = 0;
 308         for (uint32_t io_docid = 0; io_docid < num_blocks; io_docid += 32) {
 309                 uint32_t last_docid = std::min(io_docid + 32, num_blocks);
 310                 size_t io_len = offsets[last_docid] - offsets[io_docid];
 311                 if (compressed.size() < io_len) {
 312                         compressed.resize(io_len);
 313                 }
 314                 complete_pread(fd, &compressed[0], io_len, offsets[io_docid]);
 315
 316                 for (uint32_t docid = io_docid; docid < last_docid; ++docid) {
 317                         size_t relative_offset = offsets[docid] - offsets[io_docid];
 318                         size_t len = offsets[docid + 1] - offsets[docid];
 319                         matched += scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, 0, nullptr);
 320                         if (limit_matches <= 0)
 321                                 return matched;
 322                 }
 323         }
 324         return matched;
 325 }
 326
 327 // Takes the given posting list, unions it into the parts of the trigram disjunction
 328 // already read; if the list is complete, intersects with “cur_candidates”.
 329 //
 330 // Returns true if the search should be aborted (we are done).
 331 bool new_posting_list_read(TrigramDisjunction *td, vector<uint32_t> decoded, vector<uint32_t> *cur_candidates, vector<uint32_t> *tmp)
 332 {
 333         if (td->docids.empty()) {
 334                 td->docids = move(decoded);
 335         } else {
 336                 tmp->clear();
 337                 set_union(decoded.begin(), decoded.end(), td->docids.begin(), td->docids.end(), back_inserter(*tmp));
 338                 swap(*tmp, td->docids);
 339         }
 340         if (--td->remaining_trigrams_to_read > 0) {
 341                 // Need to wait for more.
 342                 if (ignore_case) {
 343                         dprintf("  ... %u reads left in OR group %u (%zu docids in list)\n",
 344                                 td->remaining_trigrams_to_read, td->index, td->docids.size());
 345                 }
 346                 return false;
 347         }
 348         if (cur_candidates->empty()) {
 349                 if (ignore_case) {
 350                         dprintf("  ... all reads done for OR group %u (%zu docids)\n",
 351                                 td->index, td->docids.size());
 352                 }
 353                 *cur_candidates = move(td->docids);
 354         } else {
 355                 tmp->clear();
 356                 set_intersection(cur_candidates->begin(), cur_candidates->end(),
 357                                  td->docids.begin(), td->docids.end(),
 358                                  back_inserter(*tmp));
 359                 swap(*cur_candidates, *tmp);
 360                 if (ignore_case) {
 361                         if (cur_candidates->empty()) {
 362                                 dprintf("  ... all reads done for OR group %u (%zu docids), intersected (none left, search is done)\n",
 363                                         td->index, td->docids.size());
 364                                 return true;
 365                         } else {
 366                                 dprintf("  ... all reads done for OR group %u (%zu docids), intersected (%zu left)\n",
 367                                         td->index, td->docids.size(), cur_candidates->size());
 368                         }
 369                 }
 370         }
 371         return false;
 372 }
 373
 374 void do_search_file(const vector<Needle> &needles, const char *filename)
 375 {
 376         int fd = open(filename, O_RDONLY);
 377         if (fd == -1) {
 378                 perror(filename);
 379                 exit(1);
 380         }
 381
 382         // Drop privileges.
 383         if (setgid(getgid()) != 0) {
 384                 perror("setgid");
 385                 exit(EXIT_FAILURE);
 386         }
 387
 388         steady_clock::time_point start __attribute__((unused)) = steady_clock::now();
 389         if (access("/", R_OK | X_OK)) {
 390                 // We can't find anything, no need to bother...
 391                 return;
 392         }
 393
 394         IOUringEngine engine(/*slop_bytes=*/16);  // 16 slop bytes as described in turbopfor.h.
 395         Corpus corpus(fd, &engine);
 396         dprintf("Corpus init done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
 397
 398         vector<TrigramDisjunction> trigram_groups;
 399         if (patterns_are_regex) {
 400                 // We could parse the regex to find trigrams that have to be there
 401                 // (there are actually known algorithms to deal with disjunctions
 402                 // and such, too), but for now, we just go brute force.
 403                 // Using locate with regexes is pretty niche.
 404         } else {
 405                 for (const Needle &needle : needles) {
 406                         parse_trigrams(needle.str, ignore_case, &trigram_groups);
 407                 }
 408         }
 409
 410         unique_sort(
 411                 &trigram_groups,
 412                 [](const TrigramDisjunction &a, const TrigramDisjunction &b) { return a.trigram_alternatives < b.trigram_alternatives; },
 413                 [](const TrigramDisjunction &a, const TrigramDisjunction &b) { return a.trigram_alternatives == b.trigram_alternatives; });
 414
 415         // Give them names for debugging.
 416         unsigned td_index = 0;
 417         for (TrigramDisjunction &td : trigram_groups) {
 418                 td.index = td_index++;
 419         }
 420
 421         // Collect which trigrams we need to look up in the hash table.
 422         unordered_map<uint32_t, vector<TrigramDisjunction *>> trigrams_to_lookup;
 423         for (TrigramDisjunction &td : trigram_groups) {
 424                 for (uint32_t trgm : td.trigram_alternatives) {
 425                         trigrams_to_lookup[trgm].push_back(&td);
 426                 }
 427         }
 428         if (trigrams_to_lookup.empty()) {
 429                 // Too short for trigram matching. Apply brute force.
 430                 // (We could have searched through all trigrams that matched
 431                 // the pattern and done a union of them, but that's a lot of
 432                 // work for fairly unclear gain.)
 433                 uint64_t matched = scan_all_docids(needles, fd, corpus, &engine);
 434                 if (only_count) {
 435                         printf("%zu\n", matched);
 436                 }
 437                 return;
 438         }
 439
 440         // Look them all up on disk.
 441         for (auto &[trgm, trigram_groups] : trigrams_to_lookup) {
 442                 corpus.find_trigram(trgm, [trgm{ trgm }, trigram_groups{ &trigram_groups }](const Trigram *trgmptr, size_t len) {
 443                         if (trgmptr == nullptr) {
 444                                 dprintf("trigram %s isn't found\n", print_trigram(trgm).c_str());
 445                                 for (TrigramDisjunction *td : *trigram_groups) {
 446                                         --td->remaining_trigrams_to_read;
 447                                         if (td->remaining_trigrams_to_read == 0 && td->read_trigrams.empty()) {
 448                                                 dprintf("zero matches in %s, so we are done\n", print_td(*td).c_str());
 449                                                 if (only_count) {
 450                                                         printf("0\n");
 451                                                 }
 452                                                 exit(0);
 453                                         }
 454                                 }
 455                                 return;
 456                         }
 457                         for (TrigramDisjunction *td : *trigram_groups) {
 458                                 --td->remaining_trigrams_to_read;
 459                                 td->max_num_docids += trgmptr->num_docids;
 460                                 td->read_trigrams.emplace_back(*trgmptr, len);
 461                         }
 462                 });
 463         }
 464         engine.finish();
 465         dprintf("Hashtable lookups done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
 466
 467         for (TrigramDisjunction &td : trigram_groups) {
 468                 // Reset for reads.
 469                 td.remaining_trigrams_to_read = td.read_trigrams.size();
 470
 471                 if (ignore_case) {  // If case-sensitive, they'll all be pretty obvious single-entry groups.
 472                         dprintf("OR group %u (max_num_docids=%u): %s\n", td.index, td.max_num_docids, print_td(td).c_str());
 473                 }
 474         }
 475
 476         // TODO: For case-insensitive (ie. more than one alternative in each),
 477         // prioritize the ones with fewer seeks?
 478         sort(trigram_groups.begin(), trigram_groups.end(),
 479              [&](const TrigramDisjunction &a, const TrigramDisjunction &b) {
 480                      return a.max_num_docids < b.max_num_docids;
 481              });
 482
 483         unordered_map<uint32_t, vector<TrigramDisjunction *>> uses_trigram;
 484         for (TrigramDisjunction &td : trigram_groups) {
 485                 for (uint32_t trgm : td.trigram_alternatives) {
 486                         uses_trigram[trgm].push_back(&td);
 487                 }
 488         }
 489
 490         unordered_set<uint32_t> trigrams_submitted_read;
 491         vector<uint32_t> cur_candidates, tmp, decoded;
 492         bool done = false;
 493         for (TrigramDisjunction &td : trigram_groups) {
 494                 if (!cur_candidates.empty() && td.max_num_docids > cur_candidates.size() * 100) {
 495                         dprintf("%s has up to %u entries, ignoring the rest (will "
 496                                 "weed out false positives later)\n",
 497                                 print_td(td).c_str(), td.max_num_docids);
 498                         break;
 499                 }
 500
 501                 for (auto &[trgmptr, len] : td.read_trigrams) {
 502                         if (trigrams_submitted_read.count(trgmptr.trgm) != 0) {
 503                                 continue;
 504                         }
 505                         trigrams_submitted_read.insert(trgmptr.trgm);
 506                         // Only stay a certain amount ahead, so that we don't spend I/O
 507                         // on reading the latter, large posting lists. We are unlikely
 508                         // to need them anyway, even if they should come in first.
 509                         if (engine.get_waiting_reads() >= 5) {
 510                                 engine.finish();
 511                                 if (done)
 512                                         break;
 513                         }
 514                         engine.submit_read(fd, len, trgmptr.offset, [trgmptr{ trgmptr }, len{ len }, &done, &cur_candidates, &tmp, &decoded, &uses_trigram](string_view s) {
 515                                 if (done)
 516                                         return;
 517
 518                                 uint32_t trgm __attribute__((unused)) = trgmptr.trgm;
 519                                 const unsigned char *pldata = reinterpret_cast<const unsigned char *>(s.data());
 520                                 size_t num = trgmptr.num_docids;
 521                                 decoded.resize(num);
 522                                 decode_pfor_delta1_128(pldata, num, /*interleaved=*/true, &decoded[0]);
 523
 524                                 assert(uses_trigram.count(trgm) != 0);
 525                                 bool was_empty = cur_candidates.empty();
 526                                 if (ignore_case) {
 527                                         dprintf("trigram %s (%zu bytes) decoded to %zu entries\n", print_trigram(trgm).c_str(), len, num);
 528                                 }
 529
 530                                 for (TrigramDisjunction *td : uses_trigram[trgm]) {
 531                                         done |= new_posting_list_read(td, decoded, &cur_candidates, &tmp);
 532                                         if (done)
 533                                                 break;
 534                                 }
 535                                 if (!ignore_case) {
 536                                         if (was_empty) {
 537                                                 dprintf("trigram %s (%zu bytes) decoded to %zu entries\n", print_trigram(trgm).c_str(), len, num);
 538                                         } else if (cur_candidates.empty()) {
 539                                                 dprintf("trigram %s (%zu bytes) decoded to %zu entries (none left, search is done)\n", print_trigram(trgm).c_str(), len, num);
 540                                         } else {
 541                                                 dprintf("trigram %s (%zu bytes) decoded to %zu entries (%zu left)\n", print_trigram(trgm).c_str(), len, num, cur_candidates.size());
 542                                         }
 543                                 }
 544                         });
 545                 }
 546         }
 547         engine.finish();
 548         if (done) {
 549                 return;
 550         }
 551         dprintf("Intersection done after %.1f ms. Doing final verification and printing:\n",
 552                 1e3 * duration<float>(steady_clock::now() - start).count());
 553
 554         uint64_t matched = scan_docids(needles, cur_candidates, corpus, &engine);
 555         dprintf("Done in %.1f ms, found %zu matches.\n",
 556                 1e3 * duration<float>(steady_clock::now() - start).count(), matched);
 557
 558         if (only_count) {
 559                 printf("%zu\n", matched);
 560         }
 561 }
 562
 563 string unescape_glob_to_plain_string(const string &needle)
 564 {
 565         string unescaped;
 566         for (size_t i = 0; i < needle.size(); i += read_unigram(needle, i).second) {
 567                 uint32_t ch = read_unigram(needle, i).first;
 568                 assert(ch != WILDCARD_UNIGRAM);
 569                 if (ch == PREMATURE_END_UNIGRAM) {
 570                         fprintf(stderr, "Pattern '%s' ended prematurely\n", needle.c_str());
 571                         exit(1);
 572                 }
 573                 unescaped.push_back(ch);
 574         }
 575         return unescaped;
 576 }
 577
 578 regex_t compile_regex(const string &needle)
 579 {
 580         regex_t re;
 581         int flags = REG_NOSUB;
 582         if (ignore_case) {
 583                 flags |= REG_ICASE;
 584         }
 585         if (use_extended_regex) {
 586                 flags |= REG_EXTENDED;
 587         }
 588         int err = regcomp(&re, needle.c_str(), flags);
 589         if (err != 0) {
 590                 char errbuf[256];
 591                 regerror(err, &re, errbuf, sizeof(errbuf));
 592                 fprintf(stderr, "Error when compiling regex '%s': %s\n", needle.c_str(), errbuf);
 593                 exit(1);
 594         }
 595         return re;
 596 }
 597
 598 void usage()
 599 {
 600         printf(
 601                 "Usage: plocate [OPTION]... PATTERN...\n"
 602                 "\n"
 603                 "  -c, --count            print number of matches instead of the matches\n"
 604                 "  -d, --database DBPATH  search for files in DBPATH\n"
 605                 "                         (default is " DEFAULT_DBPATH ")\n"
 606                 "  -i, --ignore-case      search case-insensitively\n"
 607                 "  -l, --limit LIMIT      stop after LIMIT matches\n"
 608                 "  -0, --null             delimit matches by NUL instead of newline\n"
 609                 "  -r, --regexp           interpret patterns as basic regexps (slow)\n"
 610                 "      --regex            interpret patterns as extended regexps (slow)\n"
 611                 "      --help             print this help\n"
 612                 "      --version          print version information\n");
 613 }
 614
 615 void version()
 616 {
 617         printf("plocate %s\n", PLOCATE_VERSION);
 618         printf("Copyright 2020 Steinar H. Gunderson\n");
 619         printf("License GPLv2+: GNU GPL version 2 or later <https://gnu.org/licenses/gpl.html>.\n");
 620         printf("This is free software: you are free to change and redistribute it.\n");
 621         printf("There is NO WARRANTY, to the extent permitted by law.\n");
 622         exit(0);
 623 }
 624
 625 int main(int argc, char **argv)
 626 {
 627         constexpr int EXTENDED_REGEX = 1000;
 628         static const struct option long_options[] = {
 629                 { "help", no_argument, 0, 'h' },
 630                 { "count", no_argument, 0, 'c' },
 631                 { "database", required_argument, 0, 'd' },
 632                 { "ignore-case", no_argument, 0, 'i' },
 633                 { "limit", required_argument, 0, 'l' },
 634                 { "null", no_argument, 0, '0' },
 635                 { "version", no_argument, 0, 'V' },
 636                 { "regexp", no_argument, 0, 'r' },
 637                 { "regex", no_argument, 0, EXTENDED_REGEX },
 638                 { "debug", no_argument, 0, 'D' },  // Not documented.
 639                 { 0, 0, 0, 0 }
 640         };
 641
 642         setlocale(LC_ALL, "");
 643         for (;;) {
 644                 int option_index = 0;
 645                 int c = getopt_long(argc, argv, "cd:hil:n:0VD", long_options, &option_index);
 646                 if (c == -1) {
 647                         break;
 648                 }
 649                 switch (c) {
 650                 case 'c':
 651                         only_count = true;
 652                         break;
 653                 case 'd':
 654                         dbpath = strdup(optarg);
 655                         break;
 656                 case 'h':
 657                         usage();
 658                         exit(0);
 659                 case 'i':
 660                         ignore_case = true;
 661                         break;
 662                 case 'l':
 663                 case 'n':
 664                         limit_matches = atoll(optarg);
 665                         if (limit_matches <= 0) {
 666                                 fprintf(stderr, "Error: limit must be a strictly positive number.\n");
 667                                 exit(1);
 668                         }
 669                         break;
 670                 case '0':
 671                         print_nul = true;
 672                         break;
 673                 case 'r':
 674                         patterns_are_regex = true;
 675                         break;
 676                 case EXTENDED_REGEX:
 677                         patterns_are_regex = true;
 678                         use_extended_regex = true;
 679                         break;
 680                 case 'D':
 681                         use_debug = true;
 682                         break;
 683                 case 'V':
 684                         version();
 685                         break;
 686                 default:
 687                         exit(1);
 688                 }
 689         }
 690
 691         if (use_debug) {
 692                 // Debug information would leak information about which files exist,
 693                 // so drop setgid before we open the file; one would either need to run
 694                 // as root, or use a locally-built file.
 695                 if (setgid(getgid()) != 0) {
 696                         perror("setgid");
 697                         exit(EXIT_FAILURE);
 698                 }
 699         }
 700
 701         vector<Needle> needles;
 702         for (int i = optind; i < argc; ++i) {
 703                 Needle needle;
 704                 needle.str = argv[i];
 705
 706                 // See if there are any wildcard characters, which indicates we should treat it
 707                 // as an (anchored) glob.
 708                 bool any_wildcard = false;
 709                 for (size_t i = 0; i < needle.str.size(); i += read_unigram(needle.str, i).second) {
 710                         if (read_unigram(needle.str, i).first == WILDCARD_UNIGRAM) {
 711                                 any_wildcard = true;
 712                                 break;
 713                         }
 714                 }
 715
 716                 if (patterns_are_regex) {
 717                         needle.type = Needle::REGEX;
 718                         needle.re = compile_regex(needle.str);
 719                 } else if (any_wildcard) {
 720                         needle.type = Needle::GLOB;
 721                 } else if (ignore_case) {
 722                         // strcasestr() doesn't handle locales correctly (even though LSB
 723                         // claims it should), but somehow, fnmatch() does, and it's about
 724                         // the same speed as using a regex.
 725                         needle.type = Needle::GLOB;
 726                         needle.str = "*" + needle.str + "*";
 727                 } else {
 728                         needle.type = Needle::STRSTR;
 729                         needle.str = unescape_glob_to_plain_string(needle.str);
 730                 }
 731                 needles.push_back(move(needle));
 732         }
 733         if (needles.empty()) {
 734                 fprintf(stderr, "plocate: no pattern to search for specified\n");
 735                 exit(0);
 736         }
 737         do_search_file(needles, dbpath);
 738 }