Line data Source code
1 : /*
2 : * psql - the PostgreSQL interactive terminal
3 : *
4 : * Copyright (c) 2000-2024, PostgreSQL Global Development Group
5 : *
6 : * src/bin/psql/input.c
7 : */
8 : #include "postgres_fe.h"
9 :
10 : #ifndef WIN32
11 : #include <unistd.h>
12 : #endif
13 : #include <fcntl.h>
14 : #include <limits.h>
15 :
16 : #include "common.h"
17 : #include "common/logging.h"
18 : #include "input.h"
19 : #include "settings.h"
20 : #include "tab-complete.h"
21 :
22 : #ifndef WIN32
23 : #define PSQLHISTORY ".psql_history"
24 : #else
25 : #define PSQLHISTORY "psql_history"
26 : #endif
27 :
28 : /* Runtime options for turning off readline and history */
29 : /* (of course there is no runtime command for doing that :) */
30 : #ifdef USE_READLINE
31 : static bool useReadline;
32 : static bool useHistory;
33 :
34 : static char *psql_history;
35 :
36 : static int history_lines_added;
37 :
38 :
39 : /*
40 : * Preserve newlines in saved queries by mapping '\n' to NL_IN_HISTORY
41 : *
42 : * It is assumed NL_IN_HISTORY will never be entered by the user
43 : * nor appear inside a multi-byte string. 0x00 is not properly
44 : * handled by the readline routines so it can not be used
45 : * for this purpose.
46 : */
47 : #define NL_IN_HISTORY 0x01
48 : #endif
49 :
50 : static void finishInput(void);
51 :
52 :
53 : /*
54 : * gets_interactive()
55 : *
56 : * Gets a line of interactive input, using readline if desired.
57 : *
58 : * prompt: the prompt string to be used
59 : * query_buf: buffer containing lines already read in the current command
60 : * (query_buf is not modified here, but may be consulted for tab completion)
61 : *
62 : * The result is a malloc'd string.
63 : *
64 : * Caller *must* have set up sigint_interrupt_jmp before calling.
65 : */
66 : char *
67 108 : gets_interactive(const char *prompt, PQExpBuffer query_buf)
68 : {
69 : #ifdef USE_READLINE
70 108 : if (useReadline)
71 : {
72 : char *result;
73 :
74 : /*
75 : * Some versions of readline don't notice SIGWINCH signals that arrive
76 : * when not actively reading input. The simplest fix is to always
77 : * re-read the terminal size. This leaves a window for SIGWINCH to be
78 : * missed between here and where readline() enables libreadline's
79 : * signal handler, but that's probably short enough to be ignored.
80 : */
81 : #ifdef HAVE_RL_RESET_SCREEN_SIZE
82 108 : rl_reset_screen_size();
83 : #endif
84 :
85 : /* Make current query_buf available to tab completion callback */
86 108 : tab_completion_query_buf = query_buf;
87 :
88 : /* Enable SIGINT to longjmp to sigint_interrupt_jmp */
89 108 : sigint_interrupt_enabled = true;
90 :
91 108 : result = readline(prompt);
92 :
93 : /* Disable SIGINT again */
94 108 : sigint_interrupt_enabled = false;
95 :
96 : /* Pure neatnik-ism */
97 108 : tab_completion_query_buf = NULL;
98 :
99 108 : return result;
100 : }
101 : #endif
102 :
103 0 : fputs(prompt, stdout);
104 0 : fflush(stdout);
105 0 : return gets_fromFile(stdin);
106 : }
107 :
108 :
109 : /*
110 : * Append the line to the history buffer, making sure there is a trailing '\n'
111 : */
112 : void
113 96 : pg_append_history(const char *s, PQExpBuffer history_buf)
114 : {
115 : #ifdef USE_READLINE
116 96 : if (useHistory && s)
117 : {
118 96 : appendPQExpBufferStr(history_buf, s);
119 96 : if (!s[0] || s[strlen(s) - 1] != '\n')
120 96 : appendPQExpBufferChar(history_buf, '\n');
121 : }
122 : #endif
123 96 : }
124 :
125 :
126 : /*
127 : * Emit accumulated history entry to readline's history mechanism,
128 : * then reset the buffer to empty.
129 : *
130 : * Note: we write nothing if history_buf is empty, so extra calls to this
131 : * function don't hurt. There must have been at least one line added by
132 : * pg_append_history before we'll do anything.
133 : */
134 : void
135 314 : pg_send_history(PQExpBuffer history_buf)
136 : {
137 : #ifdef USE_READLINE
138 : static char *prev_hist = NULL;
139 :
140 314 : char *s = history_buf->data;
141 : int i;
142 :
143 : /* Trim any trailing \n's (OK to scribble on history_buf) */
144 408 : for (i = strlen(s) - 1; i >= 0 && s[i] == '\n'; i--)
145 : ;
146 314 : s[i + 1] = '\0';
147 :
148 314 : if (useHistory && s[0])
149 : {
150 94 : if (((pset.histcontrol & hctl_ignorespace) &&
151 0 : s[0] == ' ') ||
152 94 : ((pset.histcontrol & hctl_ignoredups) &&
153 0 : prev_hist && strcmp(s, prev_hist) == 0))
154 : {
155 : /* Ignore this line as far as history is concerned */
156 : }
157 : else
158 : {
159 : /* Save each previous line for ignoredups processing */
160 94 : free(prev_hist);
161 94 : prev_hist = pg_strdup(s);
162 : /* And send it to readline */
163 94 : add_history(s);
164 : /* Count lines added to history for use later */
165 94 : history_lines_added++;
166 : }
167 : }
168 :
169 314 : resetPQExpBuffer(history_buf);
170 : #endif
171 314 : }
172 :
173 :
174 : /*
175 : * gets_fromFile
176 : *
177 : * Gets a line of noninteractive input from a file (which could be stdin).
178 : * The result is a malloc'd string, or NULL on EOF or input error.
179 : *
180 : * Caller *must* have set up sigint_interrupt_jmp before calling.
181 : *
182 : * Note: we re-use a static PQExpBuffer for each call. This is to avoid
183 : * leaking memory if interrupted by SIGINT.
184 : */
185 : char *
186 772814 : gets_fromFile(FILE *source)
187 : {
188 : static PQExpBuffer buffer = NULL;
189 :
190 : char line[1024];
191 :
192 772814 : if (buffer == NULL) /* first time through? */
193 15486 : buffer = createPQExpBuffer();
194 : else
195 757328 : resetPQExpBuffer(buffer);
196 :
197 : for (;;)
198 12658 : {
199 : char *result;
200 :
201 : /* Enable SIGINT to longjmp to sigint_interrupt_jmp */
202 785472 : sigint_interrupt_enabled = true;
203 :
204 : /* Get some data */
205 785472 : result = fgets(line, sizeof(line), source);
206 :
207 : /* Disable SIGINT again */
208 785472 : sigint_interrupt_enabled = false;
209 :
210 : /* EOF or error? */
211 785472 : if (result == NULL)
212 : {
213 27846 : if (ferror(source))
214 : {
215 0 : pg_log_error("could not read from input file: %m");
216 0 : return NULL;
217 : }
218 27846 : break;
219 : }
220 :
221 757626 : appendPQExpBufferStr(buffer, line);
222 :
223 757626 : if (PQExpBufferBroken(buffer))
224 : {
225 0 : pg_log_error("out of memory");
226 0 : return NULL;
227 : }
228 :
229 : /* EOL? */
230 757626 : if (buffer->len > 0 && buffer->data[buffer->len - 1] == '\n')
231 : {
232 744968 : buffer->data[buffer->len - 1] = '\0';
233 744968 : return pg_strdup(buffer->data);
234 : }
235 : }
236 :
237 27846 : if (buffer->len > 0) /* EOF after reading some bufferload(s) */
238 12530 : return pg_strdup(buffer->data);
239 :
240 : /* EOF, so return null */
241 15316 : return NULL;
242 : }
243 :
244 :
245 : #ifdef USE_READLINE
246 :
247 : /*
248 : * Macros to iterate over each element of the history list in order
249 : *
250 : * You would think this would be simple enough, but in its inimitable fashion
251 : * libedit has managed to break it: in libreadline we must use next_history()
252 : * to go from oldest to newest, but in libedit we must use previous_history().
253 : * To detect what to do, we make a trial call of previous_history(): if it
254 : * fails, then either next_history() is what to use, or there's zero or one
255 : * history entry so that it doesn't matter which direction we go.
256 : *
257 : * In case that wasn't disgusting enough: the code below is not as obvious as
258 : * it might appear. In some libedit releases history_set_pos(0) fails until
259 : * at least one add_history() call has been done. This is not an issue for
260 : * printHistory() or encode_history(), which cannot be invoked before that has
261 : * happened. In decode_history(), that's not so, and what actually happens is
262 : * that we are sitting on the newest entry to start with, previous_history()
263 : * fails, and we iterate over all the entries using next_history(). So the
264 : * decode_history() loop iterates over the entries in the wrong order when
265 : * using such a libedit release, and if there were another attempt to use
266 : * BEGIN_ITERATE_HISTORY() before some add_history() call had happened, it
267 : * wouldn't work. Fortunately we don't care about either of those things.
268 : *
269 : * Usage pattern is:
270 : *
271 : * BEGIN_ITERATE_HISTORY(varname);
272 : * {
273 : * loop body referencing varname->line;
274 : * }
275 : * END_ITERATE_HISTORY();
276 : */
277 : #define BEGIN_ITERATE_HISTORY(VARNAME) \
278 : do { \
279 : HIST_ENTRY *VARNAME; \
280 : bool use_prev_; \
281 : \
282 : history_set_pos(0); \
283 : use_prev_ = (previous_history() != NULL); \
284 : history_set_pos(0); \
285 : for (VARNAME = current_history(); VARNAME != NULL; \
286 : VARNAME = use_prev_ ? previous_history() : next_history()) \
287 : { \
288 : (void) 0
289 :
290 : #define END_ITERATE_HISTORY() \
291 : } \
292 : } while(0)
293 :
294 :
295 : /*
296 : * Convert newlines to NL_IN_HISTORY for safe saving in readline history file
297 : */
298 : static void
299 2 : encode_history(void)
300 : {
301 78 : BEGIN_ITERATE_HISTORY(cur_hist);
302 : {
303 : char *cur_ptr;
304 :
305 : /* some platforms declare HIST_ENTRY.line as const char * */
306 2128 : for (cur_ptr = (char *) cur_hist->line; *cur_ptr; cur_ptr++)
307 : {
308 2052 : if (*cur_ptr == '\n')
309 2 : *cur_ptr = NL_IN_HISTORY;
310 : }
311 : }
312 : END_ITERATE_HISTORY();
313 2 : }
314 :
315 : /*
316 : * Reverse the above encoding
317 : */
318 : static void
319 4 : decode_history(void)
320 : {
321 4 : BEGIN_ITERATE_HISTORY(cur_hist);
322 : {
323 : char *cur_ptr;
324 :
325 : /* some platforms declare HIST_ENTRY.line as const char * */
326 0 : for (cur_ptr = (char *) cur_hist->line; *cur_ptr; cur_ptr++)
327 : {
328 0 : if (*cur_ptr == NL_IN_HISTORY)
329 0 : *cur_ptr = '\n';
330 : }
331 : }
332 : END_ITERATE_HISTORY();
333 4 : }
334 : #endif /* USE_READLINE */
335 :
336 :
337 : /*
338 : * Put any startup stuff related to input in here. It's good to maintain
339 : * abstraction this way.
340 : *
341 : * The only "flag" right now is 1 for use readline & history.
342 : */
343 : void
344 4 : initializeInput(int flags)
345 : {
346 : #ifdef USE_READLINE
347 4 : if (flags & 1)
348 : {
349 : const char *histfile;
350 : char home[MAXPGPATH];
351 :
352 4 : useReadline = true;
353 :
354 : /* set appropriate values for Readline's global variables */
355 4 : initialize_readline();
356 :
357 : #ifdef HAVE_RL_VARIABLE_BIND
358 : /* set comment-begin to a useful value for SQL */
359 4 : (void) rl_variable_bind("comment-begin", "-- ");
360 : #endif
361 :
362 : /* this reads ~/.inputrc, so do it after rl_variable_bind */
363 4 : rl_initialize();
364 :
365 4 : useHistory = true;
366 4 : using_history();
367 4 : history_lines_added = 0;
368 :
369 4 : histfile = GetVariable(pset.vars, "HISTFILE");
370 :
371 4 : if (histfile == NULL)
372 : {
373 : char *envhist;
374 :
375 4 : envhist = getenv("PSQL_HISTORY");
376 4 : if (envhist != NULL && strlen(envhist) > 0)
377 4 : histfile = envhist;
378 : }
379 :
380 4 : if (histfile == NULL)
381 : {
382 0 : if (get_home_path(home))
383 0 : psql_history = psprintf("%s/%s", home, PSQLHISTORY);
384 : }
385 : else
386 : {
387 4 : psql_history = pg_strdup(histfile);
388 4 : expand_tilde(&psql_history);
389 : }
390 :
391 4 : if (psql_history)
392 : {
393 4 : read_history(psql_history);
394 4 : decode_history();
395 : }
396 : }
397 : #endif
398 :
399 4 : atexit(finishInput);
400 4 : }
401 :
402 :
403 : /*
404 : * This function saves the readline history when psql exits.
405 : *
406 : * fname: pathname of history file. (Should really be "const char *",
407 : * but some ancient versions of readline omit the const-decoration.)
408 : *
409 : * max_lines: if >= 0, limit history file to that many entries.
410 : */
411 : #ifdef USE_READLINE
412 : static bool
413 4 : saveHistory(char *fname, int max_lines)
414 : {
415 : int errnum;
416 :
417 : /*
418 : * Suppressing the write attempt when HISTFILE is set to /dev/null may
419 : * look like a negligible optimization, but it's necessary on e.g. macOS,
420 : * where write_history will fail because it tries to chmod the target
421 : * file.
422 : */
423 4 : if (strcmp(fname, DEVNULL) != 0)
424 : {
425 : /*
426 : * Encode \n, since otherwise readline will reload multiline history
427 : * entries as separate lines. (libedit doesn't really need this, but
428 : * we do it anyway since it's too hard to tell which implementation we
429 : * are using.)
430 : */
431 2 : encode_history();
432 :
433 : /*
434 : * On newer versions of libreadline, truncate the history file as
435 : * needed and then append what we've added. This avoids overwriting
436 : * history from other concurrent sessions (although there are still
437 : * race conditions when two sessions exit at about the same time). If
438 : * we don't have those functions, fall back to write_history().
439 : */
440 : #if defined(HAVE_HISTORY_TRUNCATE_FILE) && defined(HAVE_APPEND_HISTORY)
441 : {
442 : int nlines;
443 : int fd;
444 :
445 : /* truncate previous entries if needed */
446 2 : if (max_lines >= 0)
447 : {
448 2 : nlines = Max(max_lines - history_lines_added, 0);
449 2 : (void) history_truncate_file(fname, nlines);
450 : }
451 : /* append_history fails if file doesn't already exist :-( */
452 2 : fd = open(fname, O_CREAT | O_WRONLY | PG_BINARY, 0600);
453 2 : if (fd >= 0)
454 2 : close(fd);
455 : /* append the appropriate number of lines */
456 2 : if (max_lines >= 0)
457 2 : nlines = Min(max_lines, history_lines_added);
458 : else
459 0 : nlines = history_lines_added;
460 2 : errnum = append_history(nlines, fname);
461 2 : if (errnum == 0)
462 2 : return true;
463 : }
464 : #else /* don't have append support */
465 : {
466 : /* truncate what we have ... */
467 : if (max_lines >= 0)
468 : stifle_history(max_lines);
469 : /* ... and overwrite file. Tough luck for concurrent sessions. */
470 : errnum = write_history(fname);
471 : if (errnum == 0)
472 : return true;
473 : }
474 : #endif
475 :
476 0 : pg_log_error("could not save history to file \"%s\": %m", fname);
477 : }
478 2 : return false;
479 : }
480 : #endif
481 :
482 :
483 :
484 : /*
485 : * Print history to the specified file, or to the console if fname is NULL
486 : * (psql \s command)
487 : *
488 : * We used to use saveHistory() for this purpose, but that doesn't permit
489 : * use of a pager; moreover libedit's implementation behaves incompatibly
490 : * (preferring to encode its output) and may fail outright when the target
491 : * file is specified as /dev/tty.
492 : */
493 : bool
494 0 : printHistory(const char *fname, unsigned short int pager)
495 : {
496 : #ifdef USE_READLINE
497 : FILE *output;
498 : bool is_pager;
499 :
500 0 : if (!useHistory)
501 0 : return false;
502 :
503 0 : if (fname == NULL)
504 : {
505 : /* use pager, if enabled, when printing to console */
506 0 : output = PageOutput(INT_MAX, pager ? &(pset.popt.topt) : NULL);
507 0 : is_pager = true;
508 : }
509 : else
510 : {
511 0 : output = fopen(fname, "w");
512 0 : if (output == NULL)
513 : {
514 0 : pg_log_error("could not save history to file \"%s\": %m", fname);
515 0 : return false;
516 : }
517 0 : is_pager = false;
518 : }
519 :
520 0 : BEGIN_ITERATE_HISTORY(cur_hist);
521 : {
522 0 : fprintf(output, "%s\n", cur_hist->line);
523 : }
524 : END_ITERATE_HISTORY();
525 :
526 0 : if (is_pager)
527 0 : ClosePager(output);
528 : else
529 0 : fclose(output);
530 :
531 0 : return true;
532 : #else
533 : pg_log_error("history is not supported by this installation");
534 : return false;
535 : #endif
536 : }
537 :
538 :
539 : static void
540 4 : finishInput(void)
541 : {
542 : #ifdef USE_READLINE
543 4 : if (useHistory && psql_history)
544 : {
545 4 : (void) saveHistory(psql_history, pset.histsize);
546 4 : free(psql_history);
547 4 : psql_history = NULL;
548 : }
549 : #endif
550 4 : }
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