summaryrefslogtreecommitdiffstats
path: root/eval.c
blob: 6f03249639a0c4ff8c1868921fef3147e807cd9b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
/*********************************************************************
 * bfs                                                               *
 * Copyright (C) 2015-2016 Tavian Barnes <tavianator@tavianator.com> *
 *                                                                   *
 * This program is free software. It comes without any warranty, to  *
 * the extent permitted by applicable law. You can redistribute it   *
 * and/or modify it under the terms of the Do What The Fuck You Want *
 * To Public License, Version 2, as published by Sam Hocevar. See    *
 * the COPYING file or http://www.wtfpl.net/ for more details.       *
 *********************************************************************/

#include "bfs.h"
#include "bftw.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>

struct eval_state {
	/** Data about the current file. */
	struct BFTW *ftwbuf;
	/** The parsed command line. */
	const struct cmdline *cmdline;
	/** The bftw() callback return value. */
	enum bftw_action action;
	/** The eval_cmdline() return value. */
	int ret;
	/** A stat() buffer, if necessary. */
	struct stat statbuf;
};

/**
 * Report an error that occurs during evaluation.
 */
static void eval_error(struct eval_state *state) {
	pretty_error(state->cmdline->stderr_colors,
	             "'%s': %s\n", state->ftwbuf->path, strerror(errno));
	state->ret = -1;
}

/**
 * Perform a stat() call if necessary.
 */
static const struct stat *fill_statbuf(struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;
	if (!ftwbuf->statbuf) {
		if (fstatat(ftwbuf->at_fd, ftwbuf->at_path, &state->statbuf, ftwbuf->at_flags) == 0) {
			ftwbuf->statbuf = &state->statbuf;
		} else {
			eval_error(state);
		}
	}
	return ftwbuf->statbuf;
}

/**
 * Get the difference (in seconds) between two struct timespecs.
 */
static time_t timespec_diff(const struct timespec *lhs, const struct timespec *rhs) {
	time_t ret = lhs->tv_sec - rhs->tv_sec;
	if (lhs->tv_nsec < rhs->tv_nsec) {
		--ret;
	}
	return ret;
}

/**
 * Perform a comparison.
 */
static bool do_cmp(const struct expr *expr, int n) {
	switch (expr->cmp) {
	case CMP_EXACT:
		return n == expr->idata;
	case CMP_LESS:
		return n < expr->idata;
	case CMP_GREATER:
		return n > expr->idata;
	}

	return false;
}

/**
 * -true test.
 */
bool eval_true(const struct expr *expr, struct eval_state *state) {
	return true;
}

/**
 * -false test.
 */
bool eval_false(const struct expr *expr, struct eval_state *state) {
	return false;
}

/**
 * -executable, -readable, -writable tests.
 */
bool eval_access(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;
	return faccessat(ftwbuf->at_fd, ftwbuf->at_path, expr->idata, ftwbuf->at_flags) == 0;
}

/**
 * -[acm]{min,time} tests.
 */
bool eval_acmtime(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	const struct timespec *time;
	switch (expr->timefield) {
	case ATIME:
		time = &statbuf->st_atim;
		break;
	case CTIME:
		time = &statbuf->st_ctim;
		break;
	case MTIME:
		time = &statbuf->st_mtim;
		break;
	}

	time_t diff = timespec_diff(&expr->reftime, time);
	switch (expr->timeunit) {
	case MINUTES:
		diff /= 60;
		break;
	case DAYS:
		diff /= 60*60*24;
		break;
	}

	return do_cmp(expr, diff);
}

/**
 * -[ac]?newer tests.
 */
bool eval_acnewer(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	const struct timespec *time;
	switch (expr->timefield) {
	case ATIME:
		time = &statbuf->st_atim;
		break;
	case CTIME:
		time = &statbuf->st_ctim;
		break;
	case MTIME:
		time = &statbuf->st_mtim;
		break;
	}

	return time->tv_sec > expr->reftime.tv_sec
		|| (time->tv_sec == expr->reftime.tv_sec && time->tv_nsec > expr->reftime.tv_nsec);
}

/**
 * -gid test.
 */
bool eval_gid(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	return do_cmp(expr, statbuf->st_gid);
}

/**
 * -uid test.
 */
bool eval_uid(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	return do_cmp(expr, statbuf->st_uid);
}

/**
 * -delete action.
 */
bool eval_delete(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;

	int flag = 0;
	if (ftwbuf->typeflag == BFTW_DIR) {
		flag |= AT_REMOVEDIR;
	}

	if (unlinkat(ftwbuf->at_fd, ftwbuf->at_path, flag) != 0) {
		eval_error(state);
		return false;
	}

	return true;
}

/**
 * -empty test.
 */
bool eval_empty(const struct expr *expr, struct eval_state *state) {
	bool ret = false;
	struct BFTW *ftwbuf = state->ftwbuf;

	if (ftwbuf->typeflag == BFTW_DIR) {
		int dfd = openat(ftwbuf->at_fd, ftwbuf->at_path, O_DIRECTORY);
		if (dfd < 0) {
			eval_error(state);
			goto done;
		}

		DIR *dir = fdopendir(dfd);
		if (!dir) {
			eval_error(state);
			close(dfd);
			goto done;
		}

		ret = true;

		struct dirent *de;
		while ((de = readdir(dir)) != NULL) {
			if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0) {
				ret = false;
				break;
			}
		}

		closedir(dir);
	} else {
		const struct stat *statbuf = fill_statbuf(state);
		if (statbuf) {
			ret = statbuf->st_size == 0;
		}
	}

done:
	return ret;
}

/**
 * -prune action.
 */
bool eval_prune(const struct expr *expr, struct eval_state *state) {
	state->action = BFTW_SKIP_SUBTREE;
	return true;
}

/**
 * -hidden test.
 */
bool eval_hidden(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;
	return ftwbuf->nameoff > 0 && ftwbuf->path[ftwbuf->nameoff] == '.';
}

/**
 * -nohidden action.
 */
bool eval_nohidden(const struct expr *expr, struct eval_state *state) {
	if (eval_hidden(expr, state)) {
		eval_prune(expr, state);
		return false;
	} else {
		return true;
	}
}

/**
 * -inum test.
 */
bool eval_inum(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	return do_cmp(expr, statbuf->st_ino);
}

/**
 * -links test.
 */
bool eval_links(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	return do_cmp(expr, statbuf->st_nlink);
}

/**
 * -i?lname test.
 */
bool eval_lname(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;
	if (ftwbuf->typeflag != BFTW_LNK) {
		return false;
	}

	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	size_t size = statbuf->st_size + 1;
	char *name = malloc(size);
	if (!name) {
		eval_error(state);
		return false;
	}

	ssize_t ret = readlinkat(ftwbuf->at_fd, ftwbuf->at_path, name, size);
	if (ret < 0) {
		eval_error(state);
		return false;
	} else if (ret >= size) {
		return false;
	}

	name[ret] = '\0';

	bool match = fnmatch(expr->sdata, name, expr->idata) == 0;
	free(name);
	return match;
}

/**
 * -i?name test.
 */
bool eval_name(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;

	const char *name = ftwbuf->path + ftwbuf->nameoff;
	char *copy = NULL;
	if (ftwbuf->depth == 0) {
		// Any trailing slashes are not part of the name.  This can only
		// happen for the root path.
		const char *slash = strchr(name, '/');
		if (slash == name) {
			// The name of "/" (or "//", etc.) is "/"
			name = "/";
		} else if (slash) {
			copy = strdup(name);
			if (!copy) {
				eval_error(state);
				return false;
			}
			copy[slash - name] = '\0';
			name = copy;
		}
	}

	bool ret = fnmatch(expr->sdata, name, expr->idata) == 0;
	free(copy);
	return ret;
}

/**
 * -i?path test.
 */
bool eval_path(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;
	return fnmatch(expr->sdata, ftwbuf->path, expr->idata) == 0;
}

/**
 * -print action.
 */
bool eval_print(const struct expr *expr, struct eval_state *state) {
	const struct colors *colors = state->cmdline->stdout_colors;
	if (colors) {
		fill_statbuf(state);
	}

	pretty_print(colors, state->ftwbuf);
	return true;
}

/**
 * -print0 action.
 */
bool eval_print0(const struct expr *expr, struct eval_state *state) {
	const char *path = state->ftwbuf->path;
	fwrite(path, 1, strlen(path) + 1, stdout);
	return true;
}

/**
 * -quit action.
 */
bool eval_quit(const struct expr *expr, struct eval_state *state) {
	state->action = BFTW_STOP;
	return true;
}

/**
 * -samefile test.
 */
bool eval_samefile(const struct expr *expr, struct eval_state *state) {
	const struct stat *statbuf = fill_statbuf(state);
	if (!statbuf) {
		return false;
	}

	return statbuf->st_dev == expr->dev && statbuf->st_ino == expr->ino;
}

/**
 * -type test.
 */
bool eval_type(const struct expr *expr, struct eval_state *state) {
	return state->ftwbuf->typeflag == expr->idata;
}

/**
 * -xtype test.
 */
bool eval_xtype(const struct expr *expr, struct eval_state *state) {
	struct BFTW *ftwbuf = state->ftwbuf;

	bool is_root = ftwbuf->depth == 0;
	bool follow = state->cmdline->flags & (is_root ? BFTW_FOLLOW_ROOT : BFTW_FOLLOW_NONROOT);

	bool is_link = ftwbuf->typeflag == BFTW_LNK;
	if (follow == is_link) {
		return eval_type(expr, state);
	}

	// -xtype does the opposite of everything else
	int at_flags = follow ? AT_SYMLINK_NOFOLLOW : 0;

	struct stat sb;
	if (fstatat(ftwbuf->at_fd, ftwbuf->at_path, &sb, at_flags) != 0) {
		if (!follow && errno == ENOENT) {
			// Broken symlink
			return eval_type(expr, state);
		} else {
			eval_error(state);
			return false;
		}
	}

	switch (expr->idata) {
	case BFTW_BLK:
		return S_ISBLK(sb.st_mode);
	case BFTW_CHR:
		return S_ISCHR(sb.st_mode);
	case BFTW_DIR:
		return S_ISDIR(sb.st_mode);
	case BFTW_FIFO:
		return S_ISFIFO(sb.st_mode);
	case BFTW_LNK:
		return S_ISLNK(sb.st_mode);
	case BFTW_REG:
		return S_ISREG(sb.st_mode);
	case BFTW_SOCK:
		return S_ISSOCK(sb.st_mode);
	}

	return false;
}

/**
 * Evaluate a negation.
 */
bool eval_not(const struct expr *expr, struct eval_state *state) {
	return !expr->rhs->eval(expr, state);
}

/**
 * Evaluate a conjunction.
 */
bool eval_and(const struct expr *expr, struct eval_state *state) {
	return expr->lhs->eval(expr->lhs, state) && expr->rhs->eval(expr->rhs, state);
}

/**
 * Evaluate a disjunction.
 */
bool eval_or(const struct expr *expr, struct eval_state *state) {
	return expr->lhs->eval(expr->lhs, state) || expr->rhs->eval(expr->rhs, state);
}

/**
 * Evaluate the comma operator.
 */
bool eval_comma(const struct expr *expr, struct eval_state *state) {
	expr->lhs->eval(expr->lhs, state);
	return expr->rhs->eval(expr->rhs, state);
}

/**
 * Type passed as the argument to the bftw() callback.
 */
struct callback_args {
	/** The parsed command line. */
	const struct cmdline *cmdline;
	/** Eventual return value from eval_cmdline(). */
	int ret;
};

/**
 * bftw() callback.
 */
static enum bftw_action cmdline_callback(struct BFTW *ftwbuf, void *ptr) {
	struct callback_args *args = ptr;

	const struct cmdline *cmdline = args->cmdline;

	if (ftwbuf->typeflag == BFTW_ERROR) {
		pretty_error(cmdline->stderr_colors, "'%s': %s\n", ftwbuf->path, strerror(ftwbuf->error));
		return BFTW_SKIP_SUBTREE;
	}

	struct eval_state state = {
		.ftwbuf = ftwbuf,
		.cmdline = cmdline,
		.action = BFTW_CONTINUE,
		.ret = args->ret,
	};

	if (ftwbuf->depth >= cmdline->maxdepth) {
		state.action = BFTW_SKIP_SUBTREE;
	}

	// In -depth mode, only handle directories on the BFTW_POST visit
	enum bftw_visit expected_visit = BFTW_PRE;
	if ((cmdline->flags & BFTW_DEPTH)
	    && ftwbuf->typeflag == BFTW_DIR
	    && ftwbuf->depth < cmdline->maxdepth) {
		expected_visit = BFTW_POST;
	}

	if (ftwbuf->visit == expected_visit
	    && ftwbuf->depth >= cmdline->mindepth
	    && ftwbuf->depth <= cmdline->maxdepth) {
		cmdline->expr->eval(cmdline->expr, &state);
	}

	args->ret = state.ret;
	return state.action;
}

/**
 * Infer the number of open file descriptors we're allowed to have.
 */
static int infer_fdlimit() {
	int ret = 4096;

	struct rlimit rl;
	if (getrlimit(RLIMIT_NOFILE, &rl) == 0) {
		if (rl.rlim_cur != RLIM_INFINITY) {
			ret = rl.rlim_cur;
		}
	}

	// Account for std{in,out,err}, and allow an extra fd for the predicates
	int nopen = 4;

	// Check /dev/fd for the current number of open fds, if possible (we may
	// have inherited more than just the standard ones)
	DIR *dir = opendir("/dev/fd");
	if (dir) {
		nopen = 0;

		struct dirent *de;
		while ((de = readdir(dir)) != NULL) {
			if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0) {
				++nopen;
			}
		}

		closedir(dir);
	}

	if (ret > nopen) {
		ret -= nopen;
	} else {
		ret = 1;
	}

	return ret;
}

/**
 * Evaluate the command line.
 */
int eval_cmdline(const struct cmdline *cmdline) {
	if (!cmdline->expr) {
		return 0;
	}

	int nopenfd = infer_fdlimit();

	struct callback_args args = {
		.cmdline = cmdline,
		.ret = 0,
	};

	for (size_t i = 0; i < cmdline->nroots; ++i) {
		if (bftw(cmdline->roots[i], cmdline_callback, nopenfd, cmdline->flags, &args) != 0) {
			args.ret = -1;
			perror("bftw()");
		}
	}

	return args.ret;
}