2 #include "io_uring_engine.h"
18 #include <unordered_map>
23 using namespace std::chrono;
26 //#define dprintf(...) fprintf(stderr, __VA_ARGS__);
28 #include "turbopfor.h"
30 const char *dbpath = "/var/lib/mlocate/plocate.db";
31 bool only_count = false;
32 bool print_nul = false;
36 bool ready_to_print(int seq) { return next_seq == seq; }
37 void print_delayed(int seq, const vector<string> msg);
38 void release_current();
46 bool operator<(const Element &other) const
48 return seq > other.seq;
51 priority_queue<Element> pending;
54 void Serializer::print_delayed(int seq, const vector<string> msg)
56 pending.push(Element{ seq, move(msg) });
59 void Serializer::release_current()
63 // See if any delayed prints can now be dealt with.
64 while (!pending.empty() && pending.top().seq == next_seq) {
65 for (const string &msg : pending.top().msg) {
67 printf("%s%c", msg.c_str(), 0);
69 printf("%s\n", msg.c_str());
77 static inline uint32_t read_unigram(const string &s, size_t idx)
80 return (unsigned char)s[idx];
86 static inline uint32_t read_trigram(const string &s, size_t start)
88 return read_unigram(s, start) | (read_unigram(s, start + 1) << 8) |
89 (read_unigram(s, start + 2) << 16);
92 bool has_access(const char *filename,
93 unordered_map<string, bool> *access_rx_cache)
95 const char *end = strchr(filename + 1, '/');
96 while (end != nullptr) {
97 string parent_path(filename, end);
98 auto it = access_rx_cache->find(parent_path);
100 if (it == access_rx_cache->end()) {
101 ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
102 access_rx_cache->emplace(move(parent_path), ok);
109 end = strchr(end + 1, '/');
117 Corpus(int fd, IOUringEngine *engine);
119 void find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb);
120 void get_compressed_filename_block(uint32_t docid, function<void(string)> cb) const;
121 size_t get_num_filename_blocks() const;
122 off_t offset_for_block(uint32_t docid) const
124 return hdr.filename_index_offset_bytes + docid * sizeof(uint64_t);
129 IOUringEngine *const engine;
134 Corpus::Corpus(int fd, IOUringEngine *engine)
135 : fd(fd), engine(engine)
137 // Enable to test cold-cache behavior (except for access()).
139 off_t len = lseek(fd, 0, SEEK_END);
144 posix_fadvise(fd, 0, len, POSIX_FADV_DONTNEED);
147 complete_pread(fd, &hdr, sizeof(hdr), /*offset=*/0);
148 if (memcmp(hdr.magic, "\0plocate", 8) != 0) {
149 fprintf(stderr, "plocate.db is corrupt or an old version; please rebuild it.\n");
152 if (hdr.version != 0) {
153 fprintf(stderr, "plocate.db has version %u, expected 0; please rebuild it.\n", hdr.version);
163 void Corpus::find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb)
165 uint32_t bucket = hash_trigram(trgm, hdr.hashtable_size);
166 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 s) {
167 const Trigram *trgmptr = reinterpret_cast<const Trigram *>(s.data());
168 for (unsigned i = 0; i < hdr.extra_ht_slots + 1; ++i) {
169 if (trgmptr[i].trgm == trgm) {
170 cb(trgmptr + i, trgmptr[i + 1].offset - trgmptr[i].offset);
180 void Corpus::get_compressed_filename_block(uint32_t docid, function<void(string)> cb) const
182 // Read the file offset from this docid and the next one.
183 // This is always allowed, since we have a sentinel block at the end.
184 engine->submit_read(fd, sizeof(uint64_t) * 2, offset_for_block(docid), [this, cb{ move(cb) }](string s) {
185 const uint64_t *ptr = reinterpret_cast<const uint64_t *>(s.data());
186 off_t offset = ptr[0];
187 size_t len = ptr[1] - ptr[0];
188 engine->submit_read(fd, len, offset, cb);
192 size_t Corpus::get_num_filename_blocks() const
194 return hdr.num_docids;
197 uint64_t scan_file_block(const vector<string> &needles, string_view compressed,
198 unordered_map<string, bool> *access_rx_cache, int seq,
199 Serializer *serializer)
201 uint64_t matched = 0;
203 unsigned long long uncompressed_len = ZSTD_getFrameContentSize(compressed.data(), compressed.size());
204 if (uncompressed_len == ZSTD_CONTENTSIZE_UNKNOWN || uncompressed_len == ZSTD_CONTENTSIZE_ERROR) {
205 fprintf(stderr, "ZSTD_getFrameContentSize() failed\n");
210 block.resize(uncompressed_len + 1);
212 size_t err = ZSTD_decompress(&block[0], block.size(), compressed.data(),
214 if (ZSTD_isError(err)) {
215 fprintf(stderr, "ZSTD_decompress(): %s\n", ZSTD_getErrorName(err));
218 block[block.size() - 1] = '\0';
220 bool immediate_print = (serializer == nullptr || serializer->ready_to_print(seq));
221 vector<string> delayed;
223 for (const char *filename = block.data();
224 filename != block.data() + block.size();
225 filename += strlen(filename) + 1) {
227 for (const string &needle : needles) {
228 if (strstr(filename, needle.c_str()) == nullptr) {
233 if (found && has_access(filename, access_rx_cache)) {
235 if (only_count) continue;
236 if (immediate_print) {
238 printf("%s%c", filename, 0);
240 printf("%s\n", filename);
243 delayed.push_back(filename);
247 if (serializer != nullptr && !only_count) {
248 if (immediate_print) {
249 serializer->release_current();
251 serializer->print_delayed(seq, move(delayed));
257 size_t scan_docids(const vector<string> &needles, const vector<uint32_t> &docids, const Corpus &corpus, IOUringEngine *engine)
259 Serializer docids_in_order;
260 unordered_map<string, bool> access_rx_cache;
261 uint64_t matched = 0;
262 for (size_t i = 0; i < docids.size(); ++i) {
263 uint32_t docid = docids[i];
264 corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, &docids_in_order](string compressed) {
265 matched += scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order);
272 // We do this sequentially, as it's faster than scattering
273 // a lot of I/O through io_uring and hoping the kernel will
274 // coalesce it plus readahead for us.
275 uint64_t scan_all_docids(const vector<string> &needles, int fd, const Corpus &corpus, IOUringEngine *engine)
277 unordered_map<string, bool> access_rx_cache;
278 uint32_t num_blocks = corpus.get_num_filename_blocks();
279 unique_ptr<uint64_t[]> offsets(new uint64_t[num_blocks + 1]);
280 complete_pread(fd, offsets.get(), (num_blocks + 1) * sizeof(uint64_t), corpus.offset_for_block(0));
282 uint64_t matched = 0;
283 for (uint32_t io_docid = 0; io_docid < num_blocks; io_docid += 32) {
284 uint32_t last_docid = std::min(io_docid + 32, num_blocks);
285 size_t io_len = offsets[last_docid] - offsets[io_docid];
286 if (compressed.size() < io_len) {
287 compressed.resize(io_len);
289 complete_pread(fd, &compressed[0], io_len, offsets[io_docid]);
291 for (uint32_t docid = io_docid; docid < last_docid; ++docid) {
292 size_t relative_offset = offsets[docid] - offsets[io_docid];
293 size_t len = offsets[docid + 1] - offsets[docid];
294 matched += scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, 0, nullptr);
300 void do_search_file(const vector<string> &needles, const char *filename)
302 int fd = open(filename, O_RDONLY);
309 if (setgid(getgid()) != 0) {
314 steady_clock::time_point start __attribute__((unused)) = steady_clock::now();
315 if (access("/", R_OK | X_OK)) {
316 // We can't find anything, no need to bother...
320 IOUringEngine engine;
321 Corpus corpus(fd, &engine);
322 dprintf("Corpus init done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
324 vector<pair<Trigram, size_t>> trigrams;
325 uint64_t shortest_so_far = numeric_limits<uint32_t>::max();
326 for (const string &needle : needles) {
327 if (needle.size() < 3)
329 for (size_t i = 0; i < needle.size() - 2; ++i) {
330 uint32_t trgm = read_trigram(needle, i);
331 corpus.find_trigram(trgm, [trgm, &trigrams, &shortest_so_far](const Trigram *trgmptr, size_t len) {
332 if (trgmptr == nullptr) {
333 dprintf("trigram '%c%c%c' isn't found, we abort the search\n",
334 trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff);
340 if (trgmptr->num_docids > shortest_so_far * 100) {
341 dprintf("not loading trigram '%c%c%c' with %u docids, it would be ignored later anyway\n",
342 trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff,
343 trgmptr->num_docids);
345 trigrams.emplace_back(*trgmptr, len);
346 shortest_so_far = std::min<uint64_t>(shortest_so_far, trgmptr->num_docids);
352 dprintf("Hashtable lookups done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
354 if (trigrams.empty()) {
355 // Too short for trigram matching. Apply brute force.
356 // (We could have searched through all trigrams that matched
357 // the pattern and done a union of them, but that's a lot of
358 // work for fairly unclear gain.)
359 uint64_t matched = scan_all_docids(needles, fd, corpus, &engine);
360 printf("%zu\n", matched);
363 sort(trigrams.begin(), trigrams.end());
365 auto last = unique(trigrams.begin(), trigrams.end());
366 trigrams.erase(last, trigrams.end());
368 sort(trigrams.begin(), trigrams.end(),
369 [&](const pair<Trigram, size_t> &a, const pair<Trigram, size_t> &b) {
370 return a.first.num_docids < b.first.num_docids;
373 vector<uint32_t> in1, in2, out;
375 for (auto [trgmptr, len] : trigrams) {
376 if (!in1.empty() && trgmptr.num_docids > in1.size() * 100) {
377 uint32_t trgm __attribute__((unused)) = trgmptr.trgm;
378 dprintf("trigram '%c%c%c' (%zu bytes) has %u entries, ignoring the rest (will "
379 "weed out false positives later)\n",
380 trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff,
381 len, trgmptr.num_docids);
385 // Only stay a certain amount ahead, so that we don't spend I/O
386 // on reading the latter, large posting lists. We are unlikely
387 // to need them anyway, even if they should come in first.
388 if (engine.get_waiting_reads() >= 5) {
393 engine.submit_read(fd, len, trgmptr.offset, [trgmptr{trgmptr}, len{len}, &done, &in1, &in2, &out](string s) {
396 uint32_t trgm __attribute__((unused)) = trgmptr.trgm;
397 size_t num = trgmptr.num_docids;
398 unsigned char *pldata = reinterpret_cast<unsigned char *>(s.data());
400 in1.resize(num + 128);
401 decode_pfor_delta1<128>(pldata, num, /*interleaved=*/true, &in1[0]);
403 dprintf("trigram '%c%c%c' (%zu bytes) decoded to %zu entries\n", trgm & 0xff,
404 (trgm >> 8) & 0xff, (trgm >> 16) & 0xff, len, num);
406 if (in2.size() < num + 128) {
407 in2.resize(num + 128);
409 decode_pfor_delta1<128>(pldata, num, /*interleaved=*/true, &in2[0]);
412 set_intersection(in1.begin(), in1.end(), in2.begin(), in2.begin() + num,
415 dprintf("trigram '%c%c%c' (%zu bytes) decoded to %zu entries, %zu left\n",
416 trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff,
417 len, num, in1.size());
419 dprintf("no matches (intersection list is empty)\n");
429 dprintf("Intersection done after %.1f ms. Doing final verification and printing:\n",
430 1e3 * duration<float>(steady_clock::now() - start).count());
432 uint64_t matched = scan_docids(needles, in1, corpus, &engine);
433 dprintf("Done in %.1f ms, found %zu matches.\n",
434 1e3 * duration<float>(steady_clock::now() - start).count(), matched);
437 printf("%zu\n", matched);
443 // The help text comes from mlocate.
444 printf("Usage: plocate [OPTION]... PATTERN...\n");
446 printf(" -c, --count only print number of found entries\n");
447 printf(" -d, --database DBPATH use DBPATH instead of default database (which is\n");
448 printf(" %s)\n", dbpath);
449 printf(" -h, --help print this help\n");
450 printf(" -0, --null separate entries with NUL on output\n");
453 int main(int argc, char **argv)
455 static const struct option long_options[] = {
456 { "help", no_argument, 0, 'h' },
457 { "count", no_argument, 0, 'c' },
458 { "database", required_argument, 0, 'd' },
459 { "null", no_argument, 0, '0' },
464 int option_index = 0;
465 int c = getopt_long(argc, argv, "cd:h0", long_options, &option_index);
474 dbpath = strdup(optarg);
487 vector<string> needles;
488 for (int i = optind; i < argc; ++i) {
489 needles.push_back(argv[i]);
491 if (needles.empty()) {
492 fprintf(stderr, "plocate: no pattern to search for specified\n");
495 do_search_file(needles, dbpath);