Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * compress_zstd.c
4 : * Routines for archivers to write a Zstd compressed data stream.
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/bin/pg_dump/compress_zstd.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 :
15 : #include "postgres_fe.h"
16 :
17 : #include "compress_zstd.h"
18 : #include "pg_backup_utils.h"
19 :
20 : #ifndef USE_ZSTD
21 :
22 : void
23 0 : InitCompressorZstd(CompressorState *cs, const pg_compress_specification compression_spec)
24 : {
25 0 : pg_fatal("this build does not support compression with %s", "ZSTD");
26 : }
27 :
28 : void
29 0 : InitCompressFileHandleZstd(CompressFileHandle *CFH, const pg_compress_specification compression_spec)
30 : {
31 0 : pg_fatal("this build does not support compression with %s", "ZSTD");
32 : }
33 :
34 : #else
35 :
36 : #include <zstd.h>
37 :
38 : typedef struct ZstdCompressorState
39 : {
40 : /* This is a normal file to which we read/write compressed data */
41 : FILE *fp;
42 :
43 : ZSTD_CStream *cstream;
44 : ZSTD_DStream *dstream;
45 : ZSTD_outBuffer output;
46 : ZSTD_inBuffer input;
47 :
48 : /* pointer to a static string like from strerror(), for Zstd_write() */
49 : const char *zstderror;
50 : } ZstdCompressorState;
51 :
52 : static ZSTD_CStream *_ZstdCStreamParams(pg_compress_specification compress);
53 : static void EndCompressorZstd(ArchiveHandle *AH, CompressorState *cs);
54 : static void WriteDataToArchiveZstd(ArchiveHandle *AH, CompressorState *cs,
55 : const void *data, size_t dLen);
56 : static void ReadDataFromArchiveZstd(ArchiveHandle *AH, CompressorState *cs);
57 :
58 : static void
59 : _Zstd_CCtx_setParam_or_die(ZSTD_CStream *cstream,
60 : ZSTD_cParameter param, int value, char *paramname)
61 : {
62 : size_t res;
63 :
64 : res = ZSTD_CCtx_setParameter(cstream, param, value);
65 : if (ZSTD_isError(res))
66 : pg_fatal("could not set compression parameter \"%s\": %s",
67 : paramname, ZSTD_getErrorName(res));
68 : }
69 :
70 : /* Return a compression stream with parameters set per argument */
71 : static ZSTD_CStream *
72 : _ZstdCStreamParams(pg_compress_specification compress)
73 : {
74 : ZSTD_CStream *cstream;
75 :
76 : cstream = ZSTD_createCStream();
77 : if (cstream == NULL)
78 : pg_fatal("could not initialize compression library");
79 :
80 : _Zstd_CCtx_setParam_or_die(cstream, ZSTD_c_compressionLevel,
81 : compress.level, "level");
82 :
83 : if (compress.options & PG_COMPRESSION_OPTION_LONG_DISTANCE)
84 : _Zstd_CCtx_setParam_or_die(cstream,
85 : ZSTD_c_enableLongDistanceMatching,
86 : compress.long_distance, "long");
87 :
88 : return cstream;
89 : }
90 :
91 : /* Helper function for WriteDataToArchiveZstd and EndCompressorZstd */
92 : static void
93 : _ZstdWriteCommon(ArchiveHandle *AH, CompressorState *cs, bool flush)
94 : {
95 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
96 : ZSTD_inBuffer *input = &zstdcs->input;
97 : ZSTD_outBuffer *output = &zstdcs->output;
98 :
99 : /* Loop while there's any input or until flushed */
100 : while (input->pos != input->size || flush)
101 : {
102 : size_t res;
103 :
104 : output->pos = 0;
105 : res = ZSTD_compressStream2(zstdcs->cstream, output,
106 : input, flush ? ZSTD_e_end : ZSTD_e_continue);
107 :
108 : if (ZSTD_isError(res))
109 : pg_fatal("could not compress data: %s", ZSTD_getErrorName(res));
110 :
111 : /*
112 : * Extra paranoia: avoid zero-length chunks, since a zero length chunk
113 : * is the EOF marker in the custom format. This should never happen
114 : * but...
115 : */
116 : if (output->pos > 0)
117 : cs->writeF(AH, output->dst, output->pos);
118 :
119 : if (res == 0)
120 : break; /* End of frame or all input consumed */
121 : }
122 : }
123 :
124 : static void
125 : EndCompressorZstd(ArchiveHandle *AH, CompressorState *cs)
126 : {
127 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
128 :
129 : if (cs->readF != NULL)
130 : {
131 : Assert(zstdcs->cstream == NULL);
132 : ZSTD_freeDStream(zstdcs->dstream);
133 : pg_free(unconstify(void *, zstdcs->input.src));
134 : }
135 : else if (cs->writeF != NULL)
136 : {
137 : Assert(zstdcs->dstream == NULL);
138 : _ZstdWriteCommon(AH, cs, true);
139 : ZSTD_freeCStream(zstdcs->cstream);
140 : }
141 :
142 : /* output buffer may be allocated in either mode */
143 : pg_free(zstdcs->output.dst);
144 : pg_free(zstdcs);
145 : }
146 :
147 : static void
148 : WriteDataToArchiveZstd(ArchiveHandle *AH, CompressorState *cs,
149 : const void *data, size_t dLen)
150 : {
151 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
152 :
153 : zstdcs->input.src = data;
154 : zstdcs->input.size = dLen;
155 : zstdcs->input.pos = 0;
156 :
157 : _ZstdWriteCommon(AH, cs, false);
158 : }
159 :
160 : static void
161 : ReadDataFromArchiveZstd(ArchiveHandle *AH, CompressorState *cs)
162 : {
163 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
164 : ZSTD_outBuffer *output = &zstdcs->output;
165 : ZSTD_inBuffer *input = &zstdcs->input;
166 : size_t input_allocated_size = ZSTD_DStreamInSize();
167 : size_t res;
168 :
169 : for (;;)
170 : {
171 : size_t cnt;
172 :
173 : /*
174 : * Read compressed data. Note that readF can resize the buffer; the
175 : * new size is tracked and used for future loops.
176 : */
177 : input->size = input_allocated_size;
178 : cnt = cs->readF(AH, (char **) unconstify(void **, &input->src), &input->size);
179 :
180 : /* ensure that readF didn't *shrink* the buffer */
181 : Assert(input->size >= input_allocated_size);
182 : input_allocated_size = input->size;
183 : input->size = cnt;
184 : input->pos = 0;
185 :
186 : if (cnt == 0)
187 : break;
188 :
189 : /* Now decompress */
190 : while (input->pos < input->size)
191 : {
192 : output->pos = 0;
193 : res = ZSTD_decompressStream(zstdcs->dstream, output, input);
194 : if (ZSTD_isError(res))
195 : pg_fatal("could not decompress data: %s", ZSTD_getErrorName(res));
196 :
197 : /*
198 : * then write the decompressed data to the output handle
199 : */
200 : ((char *) output->dst)[output->pos] = '\0';
201 : ahwrite(output->dst, 1, output->pos, AH);
202 :
203 : if (res == 0)
204 : break; /* End of frame */
205 : }
206 : }
207 : }
208 :
209 : /* Public routine that supports Zstd compressed data I/O */
210 : void
211 : InitCompressorZstd(CompressorState *cs,
212 : const pg_compress_specification compression_spec)
213 : {
214 : ZstdCompressorState *zstdcs;
215 :
216 : cs->readData = ReadDataFromArchiveZstd;
217 : cs->writeData = WriteDataToArchiveZstd;
218 : cs->end = EndCompressorZstd;
219 :
220 : cs->compression_spec = compression_spec;
221 :
222 : zstdcs = (ZstdCompressorState *) pg_malloc0(sizeof(*zstdcs));
223 : cs->private_data = zstdcs;
224 :
225 : /* We expect that exactly one of readF/writeF is specified */
226 : Assert((cs->readF == NULL) != (cs->writeF == NULL));
227 :
228 : if (cs->readF != NULL)
229 : {
230 : zstdcs->dstream = ZSTD_createDStream();
231 : if (zstdcs->dstream == NULL)
232 : pg_fatal("could not initialize compression library");
233 :
234 : zstdcs->input.size = ZSTD_DStreamInSize();
235 : zstdcs->input.src = pg_malloc(zstdcs->input.size);
236 :
237 : /*
238 : * output.size is the buffer size we tell zstd it can output to.
239 : * Allocate an additional byte such that ReadDataFromArchiveZstd() can
240 : * call ahwrite() with a null-terminated string, which is an optimized
241 : * case in ExecuteSqlCommandBuf().
242 : */
243 : zstdcs->output.size = ZSTD_DStreamOutSize();
244 : zstdcs->output.dst = pg_malloc(zstdcs->output.size + 1);
245 : }
246 : else if (cs->writeF != NULL)
247 : {
248 : zstdcs->cstream = _ZstdCStreamParams(cs->compression_spec);
249 :
250 : zstdcs->output.size = ZSTD_CStreamOutSize();
251 : zstdcs->output.dst = pg_malloc(zstdcs->output.size);
252 : zstdcs->output.pos = 0;
253 : }
254 : }
255 :
256 : /*
257 : * Compressed stream API
258 : */
259 :
260 : static bool
261 : Zstd_read(void *ptr, size_t size, size_t *rdsize, CompressFileHandle *CFH)
262 : {
263 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
264 : ZSTD_inBuffer *input = &zstdcs->input;
265 : ZSTD_outBuffer *output = &zstdcs->output;
266 : size_t input_allocated_size = ZSTD_DStreamInSize();
267 : size_t res,
268 : cnt;
269 :
270 : output->size = size;
271 : output->dst = ptr;
272 : output->pos = 0;
273 :
274 : for (;;)
275 : {
276 : Assert(input->pos <= input->size);
277 : Assert(input->size <= input_allocated_size);
278 :
279 : /*
280 : * If the input is completely consumed, start back at the beginning
281 : */
282 : if (input->pos == input->size)
283 : {
284 : /* input->size is size produced by "fread" */
285 : input->size = 0;
286 : /* input->pos is position consumed by decompress */
287 : input->pos = 0;
288 : }
289 :
290 : /* read compressed data if we must produce more input */
291 : if (input->pos == input->size)
292 : {
293 : cnt = fread(unconstify(void *, input->src), 1, input_allocated_size, zstdcs->fp);
294 : input->size = cnt;
295 :
296 : Assert(cnt <= input_allocated_size);
297 :
298 : /* If we have no more input to consume, we're done */
299 : if (cnt == 0)
300 : break;
301 : }
302 :
303 : while (input->pos < input->size)
304 : {
305 : /* now decompress */
306 : res = ZSTD_decompressStream(zstdcs->dstream, output, input);
307 :
308 : if (ZSTD_isError(res))
309 : pg_fatal("could not decompress data: %s", ZSTD_getErrorName(res));
310 :
311 : if (output->pos == output->size)
312 : break; /* No more room for output */
313 :
314 : if (res == 0)
315 : break; /* End of frame */
316 : }
317 :
318 : if (output->pos == output->size)
319 : break; /* We read all the data that fits */
320 : }
321 :
322 : if (rdsize != NULL)
323 : *rdsize = output->pos;
324 :
325 : return true;
326 : }
327 :
328 : static bool
329 : Zstd_write(const void *ptr, size_t size, CompressFileHandle *CFH)
330 : {
331 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
332 : ZSTD_inBuffer *input = &zstdcs->input;
333 : ZSTD_outBuffer *output = &zstdcs->output;
334 : size_t res,
335 : cnt;
336 :
337 : input->src = ptr;
338 : input->size = size;
339 : input->pos = 0;
340 :
341 : /* Consume all input, to be flushed later */
342 : while (input->pos != input->size)
343 : {
344 : output->pos = 0;
345 : res = ZSTD_compressStream2(zstdcs->cstream, output, input, ZSTD_e_continue);
346 : if (ZSTD_isError(res))
347 : {
348 : zstdcs->zstderror = ZSTD_getErrorName(res);
349 : return false;
350 : }
351 :
352 : cnt = fwrite(output->dst, 1, output->pos, zstdcs->fp);
353 : if (cnt != output->pos)
354 : {
355 : zstdcs->zstderror = strerror(errno);
356 : return false;
357 : }
358 : }
359 :
360 : return size;
361 : }
362 :
363 : static int
364 : Zstd_getc(CompressFileHandle *CFH)
365 : {
366 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
367 : int ret;
368 :
369 : if (CFH->read_func(&ret, 1, NULL, CFH) != 1)
370 : {
371 : if (feof(zstdcs->fp))
372 : pg_fatal("could not read from input file: end of file");
373 : else
374 : pg_fatal("could not read from input file: %m");
375 : }
376 : return ret;
377 : }
378 :
379 : static char *
380 : Zstd_gets(char *buf, int len, CompressFileHandle *CFH)
381 : {
382 : int i;
383 :
384 : Assert(len > 0);
385 :
386 : /*
387 : * Read one byte at a time until newline or EOF. This is only used to read
388 : * the list of LOs, and the I/O is buffered anyway.
389 : */
390 : for (i = 0; i < len - 1; ++i)
391 : {
392 : size_t readsz;
393 :
394 : if (!CFH->read_func(&buf[i], 1, &readsz, CFH))
395 : break;
396 : if (readsz != 1)
397 : break;
398 : if (buf[i] == '\n')
399 : {
400 : ++i;
401 : break;
402 : }
403 : }
404 : buf[i] = '\0';
405 : return i > 0 ? buf : NULL;
406 : }
407 :
408 : static bool
409 : Zstd_close(CompressFileHandle *CFH)
410 : {
411 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
412 :
413 : if (zstdcs->cstream)
414 : {
415 : size_t res,
416 : cnt;
417 : ZSTD_inBuffer *input = &zstdcs->input;
418 : ZSTD_outBuffer *output = &zstdcs->output;
419 :
420 : /* Loop until the compression buffers are fully consumed */
421 : for (;;)
422 : {
423 : output->pos = 0;
424 : res = ZSTD_compressStream2(zstdcs->cstream, output, input, ZSTD_e_end);
425 : if (ZSTD_isError(res))
426 : {
427 : zstdcs->zstderror = ZSTD_getErrorName(res);
428 : return false;
429 : }
430 :
431 : cnt = fwrite(output->dst, 1, output->pos, zstdcs->fp);
432 : if (cnt != output->pos)
433 : {
434 : zstdcs->zstderror = strerror(errno);
435 : return false;
436 : }
437 :
438 : if (res == 0)
439 : break; /* End of frame */
440 : }
441 :
442 : ZSTD_freeCStream(zstdcs->cstream);
443 : pg_free(zstdcs->output.dst);
444 : }
445 :
446 : if (zstdcs->dstream)
447 : {
448 : ZSTD_freeDStream(zstdcs->dstream);
449 : pg_free(unconstify(void *, zstdcs->input.src));
450 : }
451 :
452 : if (fclose(zstdcs->fp) != 0)
453 : return false;
454 :
455 : pg_free(zstdcs);
456 : return true;
457 : }
458 :
459 : static bool
460 : Zstd_eof(CompressFileHandle *CFH)
461 : {
462 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
463 :
464 : return feof(zstdcs->fp);
465 : }
466 :
467 : static bool
468 : Zstd_open(const char *path, int fd, const char *mode,
469 : CompressFileHandle *CFH)
470 : {
471 : FILE *fp;
472 : ZstdCompressorState *zstdcs;
473 :
474 : if (fd >= 0)
475 : fp = fdopen(fd, mode);
476 : else
477 : fp = fopen(path, mode);
478 :
479 : if (fp == NULL)
480 : return false;
481 :
482 : zstdcs = (ZstdCompressorState *) pg_malloc0(sizeof(*zstdcs));
483 : CFH->private_data = zstdcs;
484 : zstdcs->fp = fp;
485 :
486 : if (mode[0] == 'r')
487 : {
488 : zstdcs->input.src = pg_malloc0(ZSTD_DStreamInSize());
489 : zstdcs->dstream = ZSTD_createDStream();
490 : if (zstdcs->dstream == NULL)
491 : pg_fatal("could not initialize compression library");
492 : }
493 : else if (mode[0] == 'w' || mode[0] == 'a')
494 : {
495 : zstdcs->output.size = ZSTD_CStreamOutSize();
496 : zstdcs->output.dst = pg_malloc0(zstdcs->output.size);
497 : zstdcs->cstream = _ZstdCStreamParams(CFH->compression_spec);
498 : if (zstdcs->cstream == NULL)
499 : pg_fatal("could not initialize compression library");
500 : }
501 : else
502 : pg_fatal("unhandled mode \"%s\"", mode);
503 :
504 : return true;
505 : }
506 :
507 : static bool
508 : Zstd_open_write(const char *path, const char *mode, CompressFileHandle *CFH)
509 : {
510 : char fname[MAXPGPATH];
511 :
512 : sprintf(fname, "%s.zst", path);
513 : return CFH->open_func(fname, -1, mode, CFH);
514 : }
515 :
516 : static const char *
517 : Zstd_get_error(CompressFileHandle *CFH)
518 : {
519 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
520 :
521 : return zstdcs->zstderror;
522 : }
523 :
524 : void
525 : InitCompressFileHandleZstd(CompressFileHandle *CFH,
526 : const pg_compress_specification compression_spec)
527 : {
528 : CFH->open_func = Zstd_open;
529 : CFH->open_write_func = Zstd_open_write;
530 : CFH->read_func = Zstd_read;
531 : CFH->write_func = Zstd_write;
532 : CFH->gets_func = Zstd_gets;
533 : CFH->getc_func = Zstd_getc;
534 : CFH->close_func = Zstd_close;
535 : CFH->eof_func = Zstd_eof;
536 : CFH->get_error_func = Zstd_get_error;
537 :
538 : CFH->compression_spec = compression_spec;
539 :
540 : CFH->private_data = NULL;
541 : }
542 :
543 : #endif /* USE_ZSTD */
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