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 : #include <unistd.h>
17 :
18 : #include "compress_zstd.h"
19 : #include "pg_backup_utils.h"
20 :
21 : #ifndef USE_ZSTD
22 :
23 : void
24 0 : InitCompressorZstd(CompressorState *cs, const pg_compress_specification compression_spec)
25 : {
26 0 : pg_fatal("this build does not support compression with %s", "ZSTD");
27 : }
28 :
29 : void
30 0 : InitCompressFileHandleZstd(CompressFileHandle *CFH, const pg_compress_specification compression_spec)
31 : {
32 0 : pg_fatal("this build does not support compression with %s", "ZSTD");
33 : }
34 :
35 : #else
36 :
37 : #include <zstd.h>
38 :
39 : typedef struct ZstdCompressorState
40 : {
41 : /* This is a normal file to which we read/write compressed data */
42 : FILE *fp;
43 :
44 : ZSTD_CStream *cstream;
45 : ZSTD_DStream *dstream;
46 : ZSTD_outBuffer output;
47 : ZSTD_inBuffer input;
48 :
49 : /* pointer to a static string like from strerror(), for Zstd_write() */
50 : const char *zstderror;
51 : } ZstdCompressorState;
52 :
53 : static ZSTD_CStream *_ZstdCStreamParams(pg_compress_specification compress);
54 : static void EndCompressorZstd(ArchiveHandle *AH, CompressorState *cs);
55 : static void WriteDataToArchiveZstd(ArchiveHandle *AH, CompressorState *cs,
56 : const void *data, size_t dLen);
57 : static void ReadDataFromArchiveZstd(ArchiveHandle *AH, CompressorState *cs);
58 :
59 : static void
60 : _Zstd_CCtx_setParam_or_die(ZSTD_CStream *cstream,
61 : ZSTD_cParameter param, int value, char *paramname)
62 : {
63 : size_t res;
64 :
65 : res = ZSTD_CCtx_setParameter(cstream, param, value);
66 : if (ZSTD_isError(res))
67 : pg_fatal("could not set compression parameter \"%s\": %s",
68 : paramname, ZSTD_getErrorName(res));
69 : }
70 :
71 : /* Return a compression stream with parameters set per argument */
72 : static ZSTD_CStream *
73 : _ZstdCStreamParams(pg_compress_specification compress)
74 : {
75 : ZSTD_CStream *cstream;
76 :
77 : cstream = ZSTD_createCStream();
78 : if (cstream == NULL)
79 : pg_fatal("could not initialize compression library");
80 :
81 : _Zstd_CCtx_setParam_or_die(cstream, ZSTD_c_compressionLevel,
82 : compress.level, "level");
83 :
84 : if (compress.options & PG_COMPRESSION_OPTION_LONG_DISTANCE)
85 : _Zstd_CCtx_setParam_or_die(cstream,
86 : ZSTD_c_enableLongDistanceMatching,
87 : compress.long_distance, "long");
88 :
89 : return cstream;
90 : }
91 :
92 : /* Helper function for WriteDataToArchiveZstd and EndCompressorZstd */
93 : static void
94 : _ZstdWriteCommon(ArchiveHandle *AH, CompressorState *cs, bool flush)
95 : {
96 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
97 : ZSTD_inBuffer *input = &zstdcs->input;
98 : ZSTD_outBuffer *output = &zstdcs->output;
99 :
100 : /* Loop while there's any input or until flushed */
101 : while (input->pos != input->size || flush)
102 : {
103 : size_t res;
104 :
105 : output->pos = 0;
106 : res = ZSTD_compressStream2(zstdcs->cstream, output,
107 : input, flush ? ZSTD_e_end : ZSTD_e_continue);
108 :
109 : if (ZSTD_isError(res))
110 : pg_fatal("could not compress data: %s", ZSTD_getErrorName(res));
111 :
112 : /*
113 : * Extra paranoia: avoid zero-length chunks, since a zero length chunk
114 : * is the EOF marker in the custom format. This should never happen
115 : * but...
116 : */
117 : if (output->pos > 0)
118 : cs->writeF(AH, output->dst, output->pos);
119 :
120 : if (res == 0)
121 : break; /* End of frame or all input consumed */
122 : }
123 : }
124 :
125 : static void
126 : EndCompressorZstd(ArchiveHandle *AH, CompressorState *cs)
127 : {
128 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
129 :
130 : if (cs->readF != NULL)
131 : {
132 : Assert(zstdcs->cstream == NULL);
133 : ZSTD_freeDStream(zstdcs->dstream);
134 : pg_free(unconstify(void *, zstdcs->input.src));
135 : }
136 : else if (cs->writeF != NULL)
137 : {
138 : Assert(zstdcs->dstream == NULL);
139 : _ZstdWriteCommon(AH, cs, true);
140 : ZSTD_freeCStream(zstdcs->cstream);
141 : }
142 :
143 : /* output buffer may be allocated in either mode */
144 : pg_free(zstdcs->output.dst);
145 : pg_free(zstdcs);
146 : cs->private_data = NULL;
147 : }
148 :
149 : static void
150 : WriteDataToArchiveZstd(ArchiveHandle *AH, CompressorState *cs,
151 : const void *data, size_t dLen)
152 : {
153 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
154 :
155 : zstdcs->input.src = data;
156 : zstdcs->input.size = dLen;
157 : zstdcs->input.pos = 0;
158 :
159 : _ZstdWriteCommon(AH, cs, false);
160 : }
161 :
162 : static void
163 : ReadDataFromArchiveZstd(ArchiveHandle *AH, CompressorState *cs)
164 : {
165 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) cs->private_data;
166 : ZSTD_outBuffer *output = &zstdcs->output;
167 : ZSTD_inBuffer *input = &zstdcs->input;
168 : size_t input_allocated_size = ZSTD_DStreamInSize();
169 : size_t res;
170 :
171 : for (;;)
172 : {
173 : size_t cnt;
174 :
175 : /*
176 : * Read compressed data. Note that readF can resize the buffer; the
177 : * new size is tracked and used for future loops.
178 : */
179 : input->size = input_allocated_size;
180 : cnt = cs->readF(AH, (char **) unconstify(void **, &input->src), &input->size);
181 :
182 : /* ensure that readF didn't *shrink* the buffer */
183 : Assert(input->size >= input_allocated_size);
184 : input_allocated_size = input->size;
185 : input->size = cnt;
186 : input->pos = 0;
187 :
188 : if (cnt == 0)
189 : break;
190 :
191 : /* Now decompress */
192 : while (input->pos < input->size)
193 : {
194 : output->pos = 0;
195 : res = ZSTD_decompressStream(zstdcs->dstream, output, input);
196 : if (ZSTD_isError(res))
197 : pg_fatal("could not decompress data: %s", ZSTD_getErrorName(res));
198 :
199 : /*
200 : * then write the decompressed data to the output handle
201 : */
202 : ((char *) output->dst)[output->pos] = '\0';
203 : ahwrite(output->dst, 1, output->pos, AH);
204 :
205 : if (res == 0)
206 : break; /* End of frame */
207 : }
208 : }
209 : }
210 :
211 : /* Public routine that supports Zstd compressed data I/O */
212 : void
213 : InitCompressorZstd(CompressorState *cs,
214 : const pg_compress_specification compression_spec)
215 : {
216 : ZstdCompressorState *zstdcs;
217 :
218 : cs->readData = ReadDataFromArchiveZstd;
219 : cs->writeData = WriteDataToArchiveZstd;
220 : cs->end = EndCompressorZstd;
221 :
222 : cs->compression_spec = compression_spec;
223 :
224 : zstdcs = (ZstdCompressorState *) pg_malloc0(sizeof(*zstdcs));
225 : cs->private_data = zstdcs;
226 :
227 : /* We expect that exactly one of readF/writeF is specified */
228 : Assert((cs->readF == NULL) != (cs->writeF == NULL));
229 :
230 : if (cs->readF != NULL)
231 : {
232 : zstdcs->dstream = ZSTD_createDStream();
233 : if (zstdcs->dstream == NULL)
234 : pg_fatal("could not initialize compression library");
235 :
236 : zstdcs->input.size = ZSTD_DStreamInSize();
237 : zstdcs->input.src = pg_malloc(zstdcs->input.size);
238 :
239 : /*
240 : * output.size is the buffer size we tell zstd it can output to.
241 : * Allocate an additional byte such that ReadDataFromArchiveZstd() can
242 : * call ahwrite() with a null-terminated string, which is an optimized
243 : * case in ExecuteSqlCommandBuf().
244 : */
245 : zstdcs->output.size = ZSTD_DStreamOutSize();
246 : zstdcs->output.dst = pg_malloc(zstdcs->output.size + 1);
247 : }
248 : else if (cs->writeF != NULL)
249 : {
250 : zstdcs->cstream = _ZstdCStreamParams(cs->compression_spec);
251 :
252 : zstdcs->output.size = ZSTD_CStreamOutSize();
253 : zstdcs->output.dst = pg_malloc(zstdcs->output.size);
254 : zstdcs->output.pos = 0;
255 : }
256 : }
257 :
258 : /*
259 : * Compressed stream API
260 : */
261 :
262 : static size_t
263 : Zstd_read_internal(void *ptr, size_t size, CompressFileHandle *CFH, bool exit_on_error)
264 : {
265 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
266 : ZSTD_inBuffer *input = &zstdcs->input;
267 : ZSTD_outBuffer *output = &zstdcs->output;
268 : size_t input_allocated_size = ZSTD_DStreamInSize();
269 : size_t res,
270 : cnt;
271 :
272 : /*
273 : * If this is the first call to the reading function, initialize the
274 : * required datastructures.
275 : */
276 : if (zstdcs->dstream == NULL)
277 : {
278 : zstdcs->input.src = pg_malloc0(input_allocated_size);
279 : zstdcs->dstream = ZSTD_createDStream();
280 : if (zstdcs->dstream == NULL)
281 : {
282 : if (exit_on_error)
283 : pg_fatal("could not initialize compression library");
284 : return -1;
285 : }
286 : }
287 :
288 : output->size = size;
289 : output->dst = ptr;
290 : output->pos = 0;
291 :
292 : for (;;)
293 : {
294 : Assert(input->pos <= input->size);
295 : Assert(input->size <= input_allocated_size);
296 :
297 : /*
298 : * If the input is completely consumed, start back at the beginning
299 : */
300 : if (input->pos == input->size)
301 : {
302 : /* input->size is size produced by "fread" */
303 : input->size = 0;
304 : /* input->pos is position consumed by decompress */
305 : input->pos = 0;
306 : }
307 :
308 : /* read compressed data if we must produce more input */
309 : if (input->pos == input->size)
310 : {
311 : cnt = fread(unconstify(void *, input->src), 1, input_allocated_size, zstdcs->fp);
312 : if (ferror(zstdcs->fp))
313 : {
314 : if (exit_on_error)
315 : pg_fatal("could not read from input file: %m");
316 : return -1;
317 : }
318 :
319 : input->size = cnt;
320 :
321 : Assert(cnt <= input_allocated_size);
322 :
323 : /* If we have no more input to consume, we're done */
324 : if (cnt == 0)
325 : break;
326 : }
327 :
328 : while (input->pos < input->size)
329 : {
330 : /* now decompress */
331 : res = ZSTD_decompressStream(zstdcs->dstream, output, input);
332 :
333 : if (ZSTD_isError(res))
334 : {
335 : if (exit_on_error)
336 : pg_fatal("could not decompress data: %s", ZSTD_getErrorName(res));
337 : return -1;
338 : }
339 :
340 : if (output->pos == output->size)
341 : break; /* No more room for output */
342 :
343 : if (res == 0)
344 : break; /* End of frame */
345 : }
346 :
347 : if (output->pos == output->size)
348 : break; /* We read all the data that fits */
349 : }
350 :
351 : return output->pos;
352 : }
353 :
354 : static void
355 : Zstd_write(const void *ptr, size_t size, CompressFileHandle *CFH)
356 : {
357 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
358 : ZSTD_inBuffer *input = &zstdcs->input;
359 : ZSTD_outBuffer *output = &zstdcs->output;
360 : size_t res,
361 : cnt;
362 :
363 : input->src = ptr;
364 : input->size = size;
365 : input->pos = 0;
366 :
367 : if (zstdcs->cstream == NULL)
368 : {
369 : zstdcs->output.size = ZSTD_CStreamOutSize();
370 : zstdcs->output.dst = pg_malloc0(zstdcs->output.size);
371 : zstdcs->cstream = _ZstdCStreamParams(CFH->compression_spec);
372 : if (zstdcs->cstream == NULL)
373 : pg_fatal("could not initialize compression library");
374 : }
375 :
376 : /* Consume all input, to be flushed later */
377 : while (input->pos != input->size)
378 : {
379 : output->pos = 0;
380 : res = ZSTD_compressStream2(zstdcs->cstream, output, input, ZSTD_e_continue);
381 : if (ZSTD_isError(res))
382 : pg_fatal("could not write to file: %s", ZSTD_getErrorName(res));
383 :
384 : errno = 0;
385 : cnt = fwrite(output->dst, 1, output->pos, zstdcs->fp);
386 : if (cnt != output->pos)
387 : {
388 : errno = (errno) ? errno : ENOSPC;
389 : pg_fatal("could not write to file: %m");
390 : }
391 : }
392 : }
393 :
394 : static int
395 : Zstd_getc(CompressFileHandle *CFH)
396 : {
397 : unsigned char ret;
398 :
399 : if (CFH->read_func(&ret, 1, CFH) != 1)
400 : pg_fatal("could not read from input file: end of file");
401 : return ret;
402 : }
403 :
404 : static char *
405 : Zstd_gets(char *buf, int len, CompressFileHandle *CFH)
406 : {
407 : int i;
408 :
409 : Assert(len > 0);
410 :
411 : /*
412 : * Read one byte at a time until newline or EOF. This is only used to read
413 : * the list of LOs, and the I/O is buffered anyway.
414 : */
415 : for (i = 0; i < len - 1; ++i)
416 : {
417 : if (Zstd_read_internal(&buf[i], 1, CFH, false) != 1)
418 : break;
419 : if (buf[i] == '\n')
420 : {
421 : ++i;
422 : break;
423 : }
424 : }
425 : buf[i] = '\0';
426 : return i > 0 ? buf : NULL;
427 : }
428 :
429 : static size_t
430 : Zstd_read(void *ptr, size_t size, CompressFileHandle *CFH)
431 : {
432 : return Zstd_read_internal(ptr, size, CFH, true);
433 : }
434 :
435 : static bool
436 : Zstd_close(CompressFileHandle *CFH)
437 : {
438 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
439 : bool success = true;
440 :
441 : if (zstdcs->cstream)
442 : {
443 : size_t res,
444 : cnt;
445 : ZSTD_inBuffer *input = &zstdcs->input;
446 : ZSTD_outBuffer *output = &zstdcs->output;
447 :
448 : /* Loop until the compression buffers are fully consumed */
449 : for (;;)
450 : {
451 : output->pos = 0;
452 : res = ZSTD_compressStream2(zstdcs->cstream, output, input, ZSTD_e_end);
453 : if (ZSTD_isError(res))
454 : {
455 : zstdcs->zstderror = ZSTD_getErrorName(res);
456 : success = false;
457 : break;
458 : }
459 :
460 : errno = 0;
461 : cnt = fwrite(output->dst, 1, output->pos, zstdcs->fp);
462 : if (cnt != output->pos)
463 : {
464 : errno = (errno) ? errno : ENOSPC;
465 : zstdcs->zstderror = strerror(errno);
466 : success = false;
467 : break;
468 : }
469 :
470 : if (res == 0)
471 : break; /* End of frame */
472 : }
473 :
474 : ZSTD_freeCStream(zstdcs->cstream);
475 : pg_free(zstdcs->output.dst);
476 : }
477 :
478 : if (zstdcs->dstream)
479 : {
480 : ZSTD_freeDStream(zstdcs->dstream);
481 : pg_free(unconstify(void *, zstdcs->input.src));
482 : }
483 :
484 : errno = 0;
485 : if (fclose(zstdcs->fp) != 0)
486 : {
487 : zstdcs->zstderror = strerror(errno);
488 : success = false;
489 : }
490 :
491 : pg_free(zstdcs);
492 : CFH->private_data = NULL;
493 : return success;
494 : }
495 :
496 : static bool
497 : Zstd_eof(CompressFileHandle *CFH)
498 : {
499 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
500 :
501 : return feof(zstdcs->fp);
502 : }
503 :
504 : static bool
505 : Zstd_open(const char *path, int fd, const char *mode,
506 : CompressFileHandle *CFH)
507 : {
508 : FILE *fp;
509 : ZstdCompressorState *zstdcs;
510 :
511 : /*
512 : * Clear state storage to avoid having the fd point to non-NULL memory on
513 : * error return.
514 : */
515 : CFH->private_data = NULL;
516 :
517 : zstdcs = (ZstdCompressorState *) pg_malloc_extended(sizeof(*zstdcs),
518 : MCXT_ALLOC_NO_OOM | MCXT_ALLOC_ZERO);
519 : if (!zstdcs)
520 : {
521 : errno = ENOMEM;
522 : return false;
523 : }
524 :
525 : if (fd >= 0)
526 : fp = fdopen(dup(fd), mode);
527 : else
528 : fp = fopen(path, mode);
529 :
530 : if (fp == NULL)
531 : {
532 : pg_free(zstdcs);
533 : return false;
534 : }
535 :
536 : zstdcs->fp = fp;
537 : CFH->private_data = zstdcs;
538 :
539 : return true;
540 : }
541 :
542 : static bool
543 : Zstd_open_write(const char *path, const char *mode, CompressFileHandle *CFH)
544 : {
545 : char fname[MAXPGPATH];
546 :
547 : sprintf(fname, "%s.zst", path);
548 : return CFH->open_func(fname, -1, mode, CFH);
549 : }
550 :
551 : static const char *
552 : Zstd_get_error(CompressFileHandle *CFH)
553 : {
554 : ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
555 :
556 : return zstdcs->zstderror;
557 : }
558 :
559 : void
560 : InitCompressFileHandleZstd(CompressFileHandle *CFH,
561 : const pg_compress_specification compression_spec)
562 : {
563 : CFH->open_func = Zstd_open;
564 : CFH->open_write_func = Zstd_open_write;
565 : CFH->read_func = Zstd_read;
566 : CFH->write_func = Zstd_write;
567 : CFH->gets_func = Zstd_gets;
568 : CFH->getc_func = Zstd_getc;
569 : CFH->close_func = Zstd_close;
570 : CFH->eof_func = Zstd_eof;
571 : CFH->get_error_func = Zstd_get_error;
572 :
573 : CFH->compression_spec = compression_spec;
574 :
575 : CFH->private_data = NULL;
576 : }
577 :
578 : #endif /* USE_ZSTD */
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