Branch data Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * astreamer_file.c
4 : : *
5 : : * Archive streamers that write to files. astreamer_plain_writer writes
6 : : * the whole archive to a single file, and astreamer_extractor writes
7 : : * each archive member to a separate file in a given directory.
8 : : *
9 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
10 : : *
11 : : * IDENTIFICATION
12 : : * src/fe_utils/astreamer_file.c
13 : : *-------------------------------------------------------------------------
14 : : */
15 : :
16 : : #include "postgres_fe.h"
17 : :
18 : : #include <unistd.h>
19 : :
20 : : #include "common/file_perm.h"
21 : : #include "common/logging.h"
22 : : #include "fe_utils/astreamer.h"
23 : :
24 : : typedef struct astreamer_plain_writer
25 : : {
26 : : astreamer base;
27 : : char *pathname;
28 : : FILE *file;
29 : : bool should_close_file;
30 : : } astreamer_plain_writer;
31 : :
32 : : typedef struct astreamer_extractor
33 : : {
34 : : astreamer base;
35 : : char *basepath;
36 : : const char *(*link_map) (const char *);
37 : : void (*report_output_file) (const char *);
38 : : char filename[MAXPGPATH];
39 : : FILE *file;
40 : : } astreamer_extractor;
41 : :
42 : : static void astreamer_plain_writer_content(astreamer *streamer,
43 : : astreamer_member *member,
44 : : const char *data, int len,
45 : : astreamer_archive_context context);
46 : : static void astreamer_plain_writer_finalize(astreamer *streamer);
47 : : static void astreamer_plain_writer_free(astreamer *streamer);
48 : :
49 : : static const astreamer_ops astreamer_plain_writer_ops = {
50 : : .content = astreamer_plain_writer_content,
51 : : .finalize = astreamer_plain_writer_finalize,
52 : : .free = astreamer_plain_writer_free
53 : : };
54 : :
55 : : static void astreamer_extractor_content(astreamer *streamer,
56 : : astreamer_member *member,
57 : : const char *data, int len,
58 : : astreamer_archive_context context);
59 : : static void astreamer_extractor_finalize(astreamer *streamer);
60 : : static void astreamer_extractor_free(astreamer *streamer);
61 : : static void extract_directory(const char *filename, mode_t mode);
62 : : static void extract_link(const char *filename, const char *linktarget);
63 : : static FILE *create_file_for_extract(const char *filename, mode_t mode);
64 : :
65 : : static const astreamer_ops astreamer_extractor_ops = {
66 : : .content = astreamer_extractor_content,
67 : : .finalize = astreamer_extractor_finalize,
68 : : .free = astreamer_extractor_free
69 : : };
70 : :
71 : : /*
72 : : * Create a astreamer that just writes data to a file.
73 : : *
74 : : * The caller must specify a pathname and may specify a file. The pathname is
75 : : * used for error-reporting purposes either way. If file is NULL, the pathname
76 : : * also identifies the file to which the data should be written: it is opened
77 : : * for writing and closed when done. If file is not NULL, the data is written
78 : : * there.
79 : : */
80 : : astreamer *
81 : 19 : astreamer_plain_writer_new(char *pathname, FILE *file)
82 : : {
83 : : astreamer_plain_writer *streamer;
84 : :
85 : 19 : streamer = palloc0_object(astreamer_plain_writer);
86 : 19 : *((const astreamer_ops **) &streamer->base.bbs_ops) =
87 : : &astreamer_plain_writer_ops;
88 : :
89 : 19 : streamer->pathname = pstrdup(pathname);
90 : 19 : streamer->file = file;
91 : :
92 [ + - ]: 19 : if (file == NULL)
93 : : {
94 : 19 : streamer->file = fopen(pathname, "wb");
95 [ - + ]: 19 : if (streamer->file == NULL)
96 : 0 : pg_fatal("could not create file \"%s\": %m", pathname);
97 : 19 : streamer->should_close_file = true;
98 : : }
99 : :
100 : 19 : return &streamer->base;
101 : : }
102 : :
103 : : /*
104 : : * Write archive content to file.
105 : : */
106 : : static void
107 : 30596 : astreamer_plain_writer_content(astreamer *streamer,
108 : : astreamer_member *member, const char *data,
109 : : int len, astreamer_archive_context context)
110 : : {
111 : : astreamer_plain_writer *mystreamer;
112 : :
113 : 30596 : mystreamer = (astreamer_plain_writer *) streamer;
114 : :
115 [ - + ]: 30596 : if (len == 0)
116 : 0 : return;
117 : :
118 : 30596 : errno = 0;
119 [ - + ]: 30596 : if (fwrite(data, len, 1, mystreamer->file) != 1)
120 : : {
121 : : /* if write didn't set errno, assume problem is no disk space */
122 [ # # ]: 0 : if (errno == 0)
123 : 0 : errno = ENOSPC;
124 : 0 : pg_fatal("could not write to file \"%s\": %m",
125 : : mystreamer->pathname);
126 : : }
127 : : }
128 : :
129 : : /*
130 : : * End-of-archive processing when writing to a plain file consists of closing
131 : : * the file if we opened it, but not if the caller provided it.
132 : : */
133 : : static void
134 : 19 : astreamer_plain_writer_finalize(astreamer *streamer)
135 : : {
136 : : astreamer_plain_writer *mystreamer;
137 : :
138 : 19 : mystreamer = (astreamer_plain_writer *) streamer;
139 : :
140 [ + - - + ]: 19 : if (mystreamer->should_close_file && fclose(mystreamer->file) != 0)
141 : 0 : pg_fatal("could not close file \"%s\": %m",
142 : : mystreamer->pathname);
143 : :
144 : 19 : mystreamer->file = NULL;
145 : 19 : mystreamer->should_close_file = false;
146 : 19 : }
147 : :
148 : : /*
149 : : * Free memory associated with this astreamer.
150 : : */
151 : : static void
152 : 19 : astreamer_plain_writer_free(astreamer *streamer)
153 : : {
154 : : astreamer_plain_writer *mystreamer;
155 : :
156 : 19 : mystreamer = (astreamer_plain_writer *) streamer;
157 : :
158 : : Assert(!mystreamer->should_close_file);
159 : : Assert(mystreamer->base.bbs_next == NULL);
160 : :
161 : 19 : pfree(mystreamer->pathname);
162 : 19 : pfree(mystreamer);
163 : 19 : }
164 : :
165 : : /*
166 : : * Create a astreamer that extracts an archive.
167 : : *
168 : : * All pathnames in the archive are interpreted relative to basepath.
169 : : *
170 : : * Unlike e.g. astreamer_plain_writer_new() we can't do anything useful here
171 : : * with untyped chunks; we need typed chunks which follow the rules described
172 : : * in astreamer.h. Assuming we have that, we don't need to worry about the
173 : : * original archive format; it's enough to just look at the member information
174 : : * provided and write to the corresponding file.
175 : : *
176 : : * 'link_map' is a function that will be applied to the target of any
177 : : * symbolic link, and which should return a replacement pathname to be used
178 : : * in its place. If NULL, the symbolic link target is used without
179 : : * modification.
180 : : *
181 : : * 'report_output_file' is a function that will be called each time we open a
182 : : * new output file. The pathname to that file is passed as an argument. If
183 : : * NULL, the call is skipped.
184 : : */
185 : : astreamer *
186 : 180 : astreamer_extractor_new(const char *basepath,
187 : : const char *(*link_map) (const char *),
188 : : void (*report_output_file) (const char *))
189 : : {
190 : : astreamer_extractor *streamer;
191 : :
192 : 180 : streamer = palloc0_object(astreamer_extractor);
193 : 180 : *((const astreamer_ops **) &streamer->base.bbs_ops) =
194 : : &astreamer_extractor_ops;
195 : 180 : streamer->basepath = pstrdup(basepath);
196 : 180 : streamer->link_map = link_map;
197 : 180 : streamer->report_output_file = report_output_file;
198 : :
199 : 180 : return &streamer->base;
200 : : }
201 : :
202 : : /*
203 : : * Extract archive contents to the filesystem.
204 : : */
205 : : static void
206 : 511877 : astreamer_extractor_content(astreamer *streamer, astreamer_member *member,
207 : : const char *data, int len,
208 : : astreamer_archive_context context)
209 : : {
210 : 511877 : astreamer_extractor *mystreamer = (astreamer_extractor *) streamer;
211 : : int fnamelen;
212 : :
213 : : Assert(member != NULL || context == ASTREAMER_ARCHIVE_TRAILER);
214 : : Assert(context != ASTREAMER_UNKNOWN);
215 : :
216 [ + + + + : 511877 : switch (context)
- ]
217 : : {
218 : 162452 : case ASTREAMER_MEMBER_HEADER:
219 : : Assert(mystreamer->file == NULL);
220 : :
221 [ - + ]: 162452 : if (!path_is_safe_for_extraction(member->pathname))
222 : 0 : pg_fatal("tar member has unsafe path name: \"%s\"",
223 : : member->pathname);
224 : :
225 : : /* Prepend basepath. */
226 : 162452 : snprintf(mystreamer->filename, sizeof(mystreamer->filename),
227 : 162452 : "%s/%s", mystreamer->basepath, member->pathname);
228 : :
229 : : /* Remove any trailing slash. */
230 : 162452 : fnamelen = strlen(mystreamer->filename);
231 [ + + ]: 162452 : if (mystreamer->filename[fnamelen - 1] == '/')
232 : 3977 : mystreamer->filename[fnamelen - 1] = '\0';
233 : :
234 : : /* Dispatch based on file type. */
235 [ + + ]: 162452 : if (member->is_regular)
236 : 158475 : mystreamer->file =
237 : 158475 : create_file_for_extract(mystreamer->filename,
238 : : member->mode);
239 [ + + ]: 3977 : else if (member->is_directory)
240 : 3961 : extract_directory(mystreamer->filename, member->mode);
241 [ + - ]: 16 : else if (member->is_symlink)
242 : : {
243 : 16 : const char *linktarget = member->linktarget;
244 : :
245 [ + - ]: 16 : if (mystreamer->link_map)
246 : 16 : linktarget = mystreamer->link_map(linktarget);
247 : :
248 [ - + ]: 16 : if (!is_absolute_path(linktarget) &&
249 [ # # ]: 0 : !path_is_safe_for_extraction(member->linktarget))
250 : : {
251 : 0 : pg_fatal("link target has unsafe path name: \"%s\"",
252 : : member->linktarget);
253 : : }
254 : :
255 : 16 : extract_link(mystreamer->filename, linktarget);
256 : : }
257 : :
258 : : /* Report output file change. */
259 [ + - ]: 162452 : if (mystreamer->report_output_file)
260 : 162452 : mystreamer->report_output_file(mystreamer->filename);
261 : 162452 : break;
262 : :
263 : 186797 : case ASTREAMER_MEMBER_CONTENTS:
264 [ - + ]: 186797 : if (mystreamer->file == NULL)
265 : 0 : break;
266 : :
267 : 186797 : errno = 0;
268 [ + + - + ]: 186797 : if (len > 0 && fwrite(data, len, 1, mystreamer->file) != 1)
269 : : {
270 : : /* if write didn't set errno, assume problem is no disk space */
271 [ # # ]: 0 : if (errno == 0)
272 : 0 : errno = ENOSPC;
273 : 0 : pg_fatal("could not write to file \"%s\": %m",
274 : : mystreamer->filename);
275 : : }
276 : 186797 : break;
277 : :
278 : 162450 : case ASTREAMER_MEMBER_TRAILER:
279 [ + + ]: 162450 : if (mystreamer->file == NULL)
280 : 3977 : break;
281 [ - + ]: 158473 : if (fclose(mystreamer->file) != 0)
282 : 0 : pg_fatal("could not close file \"%s\": %m",
283 : : mystreamer->filename);
284 : 158473 : mystreamer->file = NULL;
285 : 158473 : break;
286 : :
287 : 178 : case ASTREAMER_ARCHIVE_TRAILER:
288 : 178 : break;
289 : :
290 : 0 : default:
291 : : /* Shouldn't happen. */
292 : 0 : pg_fatal("unexpected state while extracting archive");
293 : : }
294 : 511877 : }
295 : :
296 : : /*
297 : : * Should we tolerate an already-existing directory?
298 : : *
299 : : * When streaming WAL, pg_wal (or pg_xlog for pre-9.6 clusters) will have been
300 : : * created by the wal receiver process. Also, when the WAL directory location
301 : : * was specified, pg_wal (or pg_xlog) has already been created as a symbolic
302 : : * link before starting the actual backup. So just ignore creation failures
303 : : * on related directories.
304 : : *
305 : : * If in-place tablespaces are used, pg_tblspc and subdirectories may already
306 : : * exist when we get here. So tolerate that case, too.
307 : : */
308 : : static bool
309 : 439 : should_allow_existing_directory(const char *pathname)
310 : : {
311 : 439 : const char *filename = last_dir_separator(pathname) + 1;
312 : :
313 [ + + ]: 439 : if (strcmp(filename, "pg_wal") == 0 ||
314 [ + - ]: 300 : strcmp(filename, "pg_xlog") == 0 ||
315 [ + + ]: 300 : strcmp(filename, "archive_status") == 0 ||
316 [ + + ]: 161 : strcmp(filename, "summaries") == 0 ||
317 [ + + ]: 22 : strcmp(filename, "pg_tblspc") == 0)
318 : 425 : return true;
319 : :
320 [ + - ]: 14 : if (strspn(filename, "0123456789") == strlen(filename))
321 : : {
322 : 14 : const char *pg_tblspc = strstr(pathname, "/pg_tblspc/");
323 : :
324 [ + - + - ]: 14 : return pg_tblspc != NULL && pg_tblspc + 11 == filename;
325 : : }
326 : :
327 : 0 : return false;
328 : : }
329 : :
330 : : /*
331 : : * Create a directory.
332 : : */
333 : : static void
334 : 3961 : extract_directory(const char *filename, mode_t mode)
335 : : {
336 [ + + ]: 3961 : if (mkdir(filename, pg_dir_create_mode) != 0 &&
337 [ + - - + ]: 439 : (errno != EEXIST || !should_allow_existing_directory(filename)))
338 : 0 : pg_fatal("could not create directory \"%s\": %m",
339 : : filename);
340 : :
341 : : #ifndef WIN32
342 [ - + ]: 3961 : if (chmod(filename, mode))
343 : 0 : pg_fatal("could not set permissions on directory \"%s\": %m",
344 : : filename);
345 : : #endif
346 : 3961 : }
347 : :
348 : : /*
349 : : * Create a symbolic link.
350 : : *
351 : : * It's most likely a link in pg_tblspc directory, to the location of a
352 : : * tablespace. Apply any tablespace mapping given on the command line
353 : : * (--tablespace-mapping). (We blindly apply the mapping without checking that
354 : : * the link really is inside pg_tblspc. We don't expect there to be other
355 : : * symlinks in a data directory, but if there are, you can call it an
356 : : * undocumented feature that you can map them too.)
357 : : */
358 : : static void
359 : 16 : extract_link(const char *filename, const char *linktarget)
360 : : {
361 [ - + ]: 16 : if (symlink(linktarget, filename) != 0)
362 : 0 : pg_fatal("could not create symbolic link from \"%s\" to \"%s\": %m",
363 : : filename, linktarget);
364 : 16 : }
365 : :
366 : : /*
367 : : * Create a regular file.
368 : : *
369 : : * Return the resulting handle so we can write the content to the file.
370 : : */
371 : : static FILE *
372 : 158475 : create_file_for_extract(const char *filename, mode_t mode)
373 : : {
374 : : FILE *file;
375 : :
376 : 158475 : file = fopen(filename, "wb");
377 [ - + ]: 158475 : if (file == NULL)
378 : 0 : pg_fatal("could not create file \"%s\": %m", filename);
379 : :
380 : : #ifndef WIN32
381 [ - + ]: 158475 : if (chmod(filename, mode))
382 : 0 : pg_fatal("could not set permissions on file \"%s\": %m",
383 : : filename);
384 : : #endif
385 : :
386 : 158475 : return file;
387 : : }
388 : :
389 : : /*
390 : : * End-of-stream processing for extracting an archive.
391 : : *
392 : : * There's nothing to do here but sanity checking.
393 : : */
394 : : static void
395 : 178 : astreamer_extractor_finalize(astreamer *streamer)
396 : : {
397 : 178 : astreamer_extractor *mystreamer PG_USED_FOR_ASSERTS_ONLY
398 : : = (astreamer_extractor *) streamer;
399 : :
400 : : Assert(mystreamer->file == NULL);
401 : 178 : }
402 : :
403 : : /*
404 : : * Free memory.
405 : : */
406 : : static void
407 : 178 : astreamer_extractor_free(astreamer *streamer)
408 : : {
409 : 178 : astreamer_extractor *mystreamer = (astreamer_extractor *) streamer;
410 : :
411 : 178 : pfree(mystreamer->basepath);
412 : 178 : pfree(mystreamer);
413 : 178 : }
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