Line data Source code
1 : /*
2 : * psql - the PostgreSQL interactive terminal
3 : *
4 : * Copyright (c) 2000-2025, PostgreSQL Global Development Group
5 : *
6 : * src/bin/psql/variables.c
7 : */
8 : #include "postgres_fe.h"
9 :
10 : #include <math.h>
11 :
12 : #include "common.h"
13 : #include "common/logging.h"
14 : #include "variables.h"
15 :
16 : /*
17 : * Check whether a variable's name is allowed.
18 : *
19 : * We allow any non-ASCII character, as well as ASCII letters, digits, and
20 : * underscore. Keep this in sync with the definition of variable_char in
21 : * psqlscan.l and psqlscanslash.l.
22 : */
23 : static bool
24 3226394 : valid_variable_name(const char *name)
25 : {
26 3226394 : const unsigned char *ptr = (const unsigned char *) name;
27 :
28 : /* Mustn't be zero-length */
29 3226394 : if (*ptr == '\0')
30 0 : return false;
31 :
32 45073044 : while (*ptr)
33 : {
34 41846662 : if (IS_HIGHBIT_SET(*ptr) ||
35 41846662 : strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
36 41846662 : "_0123456789", *ptr) != NULL)
37 41846650 : ptr++;
38 : else
39 12 : return false;
40 : }
41 :
42 3226382 : return true;
43 : }
44 :
45 : /*
46 : * A "variable space" is represented by an otherwise-unused struct _variable
47 : * that serves as list header.
48 : *
49 : * The list entries are kept in name order (according to strcmp). This
50 : * is mainly to make the output of PrintVariables() more pleasing.
51 : */
52 : VariableSpace
53 19864 : CreateVariableSpace(void)
54 : {
55 : struct _variable *ptr;
56 :
57 19864 : ptr = pg_malloc(sizeof *ptr);
58 19864 : ptr->name = NULL;
59 19864 : ptr->value = NULL;
60 19864 : ptr->substitute_hook = NULL;
61 19864 : ptr->assign_hook = NULL;
62 19864 : ptr->next = NULL;
63 :
64 19864 : return ptr;
65 : }
66 :
67 : /*
68 : * Get string value of variable, or NULL if it's not defined.
69 : *
70 : * Note: result is valid until variable is next assigned to.
71 : */
72 : const char *
73 3822 : GetVariable(VariableSpace space, const char *name)
74 : {
75 : struct _variable *current;
76 :
77 3822 : if (!space)
78 0 : return NULL;
79 :
80 146450 : for (current = space->next; current; current = current->next)
81 : {
82 146448 : int cmp = strcmp(current->name, name);
83 :
84 146448 : if (cmp == 0)
85 : {
86 : /* this is correct answer when value is NULL, too */
87 3340 : return current->value;
88 : }
89 143108 : if (cmp > 0)
90 480 : break; /* it's not there */
91 : }
92 :
93 482 : return NULL;
94 : }
95 :
96 : /*
97 : * Try to interpret "value" as a boolean value, and if successful,
98 : * store it in *result. Otherwise don't clobber *result.
99 : *
100 : * Valid values are: true, false, yes, no, on, off, 1, 0; as well as unique
101 : * prefixes thereof.
102 : *
103 : * "name" is the name of the variable we're assigning to, to use in error
104 : * report if any. Pass name == NULL to suppress the error report.
105 : *
106 : * Return true when "value" is syntactically valid, false otherwise.
107 : */
108 : bool
109 269704 : ParseVariableBool(const char *value, const char *name, bool *result)
110 : {
111 : size_t len;
112 269704 : bool valid = true;
113 :
114 : /* Treat "unset" as an empty string, which will lead to error below */
115 269704 : if (value == NULL)
116 0 : value = "";
117 :
118 269704 : len = strlen(value);
119 :
120 269704 : if (len > 0 && pg_strncasecmp(value, "true", len) == 0)
121 224 : *result = true;
122 269480 : else if (len > 0 && pg_strncasecmp(value, "false", len) == 0)
123 258 : *result = false;
124 269222 : else if (len > 0 && pg_strncasecmp(value, "yes", len) == 0)
125 6 : *result = true;
126 269216 : else if (len > 0 && pg_strncasecmp(value, "no", len) == 0)
127 6 : *result = false;
128 : /* 'o' is not unique enough */
129 269210 : else if (pg_strncasecmp(value, "on", (len > 2 ? len : 2)) == 0)
130 58680 : *result = true;
131 210530 : else if (pg_strncasecmp(value, "off", (len > 2 ? len : 2)) == 0)
132 198846 : *result = false;
133 11684 : else if (pg_strcasecmp(value, "1") == 0)
134 11658 : *result = true;
135 26 : else if (pg_strcasecmp(value, "0") == 0)
136 8 : *result = false;
137 : else
138 : {
139 : /* string is not recognized; don't clobber *result */
140 18 : if (name)
141 12 : pg_log_error("unrecognized value \"%s\" for \"%s\": Boolean expected",
142 : value, name);
143 18 : valid = false;
144 : }
145 269704 : return valid;
146 : }
147 :
148 : /*
149 : * Try to interpret "value" as an integer value, and if successful,
150 : * store it in *result. Otherwise don't clobber *result.
151 : *
152 : * "name" is the name of the variable we're assigning to, to use in error
153 : * report if any. Pass name == NULL to suppress the error report.
154 : *
155 : * Return true when "value" is syntactically valid, false otherwise.
156 : */
157 : bool
158 59672 : ParseVariableNum(const char *value, const char *name, int *result)
159 : {
160 : char *end;
161 : long numval;
162 :
163 : /* Treat "unset" as an empty string, which will lead to error below */
164 59672 : if (value == NULL)
165 0 : value = "";
166 :
167 59672 : errno = 0;
168 59672 : numval = strtol(value, &end, 0);
169 59672 : if (errno == 0 && *end == '\0' && end != value && numval == (int) numval)
170 : {
171 59666 : *result = (int) numval;
172 59666 : return true;
173 : }
174 : else
175 : {
176 : /* string is not recognized; don't clobber *result */
177 6 : if (name)
178 6 : pg_log_error("invalid value \"%s\" for \"%s\": integer expected",
179 : value, name);
180 6 : return false;
181 : }
182 : }
183 :
184 : /*
185 : * Try to interpret "value" as a double value, and if successful store it in
186 : * *result. If unsuccessful, *result isn't clobbered. "name" is the variable
187 : * which is being assigned, the value of which is only used to produce a good
188 : * error message. Pass NULL as the name to suppress the error message. The
189 : * value must be within the range [min,max] in order to be considered valid.
190 : *
191 : * Returns true, with *result containing the interpreted value, if "value" is
192 : * syntactically valid, else false (with *result unchanged).
193 : */
194 : bool
195 19872 : ParseVariableDouble(const char *value, const char *name, double *result, double min, double max)
196 : {
197 : char *end;
198 : double dblval;
199 :
200 : /*
201 : * Empty-string input has historically been treated differently by strtod
202 : * on various platforms, so handle that by specifically checking for it.
203 : */
204 19872 : if ((value == NULL) || (*value == '\0'))
205 : {
206 0 : if (name)
207 0 : pg_log_error("invalid input syntax for \"%s\"", name);
208 0 : return false;
209 : }
210 :
211 19872 : errno = 0;
212 19872 : dblval = strtod(value, &end);
213 19872 : if (errno == 0 && *end == '\0' && end != value)
214 : {
215 19870 : if (dblval < min)
216 : {
217 0 : if (name)
218 0 : pg_log_error("invalid value \"%s\" for \"%s\": must be greater than %.2f",
219 : value, name, min);
220 0 : return false;
221 : }
222 19870 : else if (dblval > max)
223 : {
224 0 : if (name)
225 0 : pg_log_error("invalid value \"%s\" for \"%s\": must be less than %.2f",
226 : value, name, max);
227 : }
228 19870 : *result = dblval;
229 19870 : return true;
230 : }
231 :
232 : /*
233 : * Cater for platforms which treat values which aren't zero, but that are
234 : * too close to zero to have full precision, by checking for zero or real
235 : * out-of-range values.
236 : */
237 2 : else if ((errno == ERANGE) &&
238 2 : (dblval == 0.0 || dblval >= HUGE_VAL || dblval <= -HUGE_VAL))
239 : {
240 2 : if (name)
241 2 : pg_log_error("\"%s\" is out of range for \"%s\"", value, name);
242 2 : return false;
243 : }
244 : else
245 : {
246 0 : if (name)
247 0 : pg_log_error("invalid value \"%s\" for \"%s\"", value, name);
248 0 : return false;
249 : }
250 : }
251 :
252 : /*
253 : * Print values of all variables.
254 : */
255 : void
256 0 : PrintVariables(VariableSpace space)
257 : {
258 : struct _variable *ptr;
259 :
260 0 : if (!space)
261 0 : return;
262 :
263 0 : for (ptr = space->next; ptr; ptr = ptr->next)
264 : {
265 0 : if (ptr->value)
266 0 : printf("%s = '%s'\n", ptr->name, ptr->value);
267 0 : if (cancel_pressed)
268 0 : break;
269 : }
270 : }
271 :
272 : /*
273 : * Set the variable named "name" to value "value",
274 : * or delete it if "value" is NULL.
275 : *
276 : * Returns true if successful, false if not; in the latter case a suitable
277 : * error message has been printed, except for the unexpected case of
278 : * space or name being NULL.
279 : */
280 : bool
281 2769522 : SetVariable(VariableSpace space, const char *name, const char *value)
282 : {
283 : struct _variable *current,
284 : *previous;
285 :
286 2769522 : if (!space || !name)
287 0 : return false;
288 :
289 2769522 : if (!valid_variable_name(name))
290 : {
291 : /* Deletion of non-existent variable is not an error */
292 12 : if (!value)
293 0 : return true;
294 12 : pg_log_error("invalid variable name: \"%s\"", name);
295 12 : return false;
296 : }
297 :
298 59427542 : for (previous = space, current = space->next;
299 : current;
300 56658032 : previous = current, current = current->next)
301 : {
302 59426876 : int cmp = strcmp(current->name, name);
303 :
304 59426876 : if (cmp == 0)
305 : {
306 : /*
307 : * Found entry, so update, unless assign hook returns false.
308 : *
309 : * We must duplicate the passed value to start with. This
310 : * simplifies the API for substitute hooks. Moreover, some assign
311 : * hooks assume that the passed value has the same lifespan as the
312 : * variable. Having to free the string again on failure is a
313 : * small price to pay for keeping these APIs simple.
314 : */
315 2386918 : char *new_value = value ? pg_strdup(value) : NULL;
316 : bool confirmed;
317 :
318 2386918 : if (current->substitute_hook)
319 72648 : new_value = current->substitute_hook(new_value);
320 :
321 2386918 : if (current->assign_hook)
322 132240 : confirmed = current->assign_hook(new_value);
323 : else
324 2254678 : confirmed = true;
325 :
326 2386918 : if (confirmed)
327 : {
328 2386898 : pg_free(current->value);
329 2386898 : current->value = new_value;
330 :
331 : /*
332 : * If we deleted the value, and there are no hooks to
333 : * remember, we can discard the variable altogether.
334 : */
335 2386898 : if (new_value == NULL &&
336 6 : current->substitute_hook == NULL &&
337 6 : current->assign_hook == NULL)
338 : {
339 6 : previous->next = current->next;
340 6 : free(current->name);
341 6 : free(current);
342 : }
343 : }
344 : else
345 20 : pg_free(new_value); /* current->value is left unchanged */
346 :
347 2386918 : return confirmed;
348 : }
349 57039958 : if (cmp > 0)
350 381926 : break; /* it's not there */
351 : }
352 :
353 : /* not present, make new entry ... unless we were asked to delete */
354 382592 : if (value)
355 : {
356 362736 : current = pg_malloc(sizeof *current);
357 362736 : current->name = pg_strdup(name);
358 362736 : current->value = pg_strdup(value);
359 362736 : current->substitute_hook = NULL;
360 362736 : current->assign_hook = NULL;
361 362736 : current->next = previous->next;
362 362736 : previous->next = current;
363 : }
364 382592 : return true;
365 : }
366 :
367 : /*
368 : * Attach substitute and/or assign hook functions to the named variable.
369 : * If you need only one hook, pass NULL for the other.
370 : *
371 : * If the variable doesn't already exist, create it with value NULL, just so
372 : * we have a place to store the hook function(s). (The substitute hook might
373 : * immediately change the NULL to something else; if not, this state is
374 : * externally the same as the variable not being defined.)
375 : *
376 : * The substitute hook, if given, is immediately called on the variable's
377 : * value. Then the assign hook, if given, is called on the variable's value.
378 : * This is meant to let it update any derived psql state. If the assign hook
379 : * doesn't like the current value, it will print a message to that effect,
380 : * but we'll ignore it. Generally we do not expect any such failure here,
381 : * because this should get called before any user-supplied value is assigned.
382 : */
383 : void
384 456872 : SetVariableHooks(VariableSpace space, const char *name,
385 : VariableSubstituteHook shook,
386 : VariableAssignHook ahook)
387 : {
388 : struct _variable *current,
389 : *previous;
390 :
391 456872 : if (!space || !name)
392 0 : return;
393 :
394 456872 : if (!valid_variable_name(name))
395 0 : return;
396 :
397 3476200 : for (previous = space, current = space->next;
398 : current;
399 3019328 : previous = current, current = current->next)
400 : {
401 3337152 : int cmp = strcmp(current->name, name);
402 :
403 3337152 : if (cmp == 0)
404 : {
405 : /* found entry, so update */
406 0 : current->substitute_hook = shook;
407 0 : current->assign_hook = ahook;
408 0 : if (shook)
409 0 : current->value = (*shook) (current->value);
410 0 : if (ahook)
411 0 : (void) (*ahook) (current->value);
412 0 : return;
413 : }
414 3337152 : if (cmp > 0)
415 317824 : break; /* it's not there */
416 : }
417 :
418 : /* not present, make new entry */
419 456872 : current = pg_malloc(sizeof *current);
420 456872 : current->name = pg_strdup(name);
421 456872 : current->value = NULL;
422 456872 : current->substitute_hook = shook;
423 456872 : current->assign_hook = ahook;
424 456872 : current->next = previous->next;
425 456872 : previous->next = current;
426 456872 : if (shook)
427 377416 : current->value = (*shook) (current->value);
428 456872 : if (ahook)
429 456872 : (void) (*ahook) (current->value);
430 : }
431 :
432 : /*
433 : * Return true iff the named variable has substitute and/or assign hook
434 : * functions.
435 : */
436 : bool
437 904 : VariableHasHook(VariableSpace space, const char *name)
438 : {
439 : struct _variable *current;
440 :
441 : Assert(space);
442 : Assert(name);
443 :
444 45074 : for (current = space->next; current; current = current->next)
445 : {
446 44760 : int cmp = strcmp(current->name, name);
447 :
448 44760 : if (cmp == 0)
449 274 : return (current->substitute_hook != NULL ||
450 134 : current->assign_hook != NULL);
451 44620 : if (cmp > 0)
452 450 : break; /* it's not there */
453 : }
454 :
455 764 : return false;
456 : }
457 :
458 : /*
459 : * Convenience function to set a variable's value to "on".
460 : */
461 : bool
462 54478 : SetVariableBool(VariableSpace space, const char *name)
463 : {
464 54478 : return SetVariable(space, name, "on");
465 : }
466 :
467 : /*
468 : * Attempt to delete variable.
469 : *
470 : * If unsuccessful, print a message and return "false".
471 : * Deleting a nonexistent variable is not an error.
472 : */
473 : bool
474 0 : DeleteVariable(VariableSpace space, const char *name)
475 : {
476 0 : return SetVariable(space, name, NULL);
477 : }
478 :
479 : /*
480 : * Emit error with suggestions for variables or commands
481 : * accepting enum-style arguments.
482 : * This function just exists to standardize the wording.
483 : * suggestions should follow the format "fee, fi, fo, fum".
484 : */
485 : void
486 6 : PsqlVarEnumError(const char *name, const char *value, const char *suggestions)
487 : {
488 6 : pg_log_error("unrecognized value \"%s\" for \"%s\"\n"
489 : "Available values are: %s.",
490 : value, name, suggestions);
491 6 : }
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