xref: /freebsd/libexec/rtld-elf/libmap.c (revision cddbc3b40812213ff00041f79174cac0be360a2a)
1 /*
2  * $FreeBSD$
3  */
4 
5 #include <sys/types.h>
6 #include <sys/param.h>
7 #include <sys/fcntl.h>
8 #include <sys/mman.h>
9 #include <sys/queue.h>
10 #include <sys/stat.h>
11 #include <dirent.h>
12 #include <errno.h>
13 #include <stdlib.h>
14 #include <string.h>
15 
16 #include "debug.h"
17 #include "rtld.h"
18 #include "libmap.h"
19 #include "paths.h"
20 
21 TAILQ_HEAD(lm_list, lm);
22 struct lm {
23 	char *f;
24 	char *t;
25 	TAILQ_ENTRY(lm)	lm_link;
26 };
27 
28 static TAILQ_HEAD(lmp_list, lmp) lmp_head = TAILQ_HEAD_INITIALIZER(lmp_head);
29 struct lmp {
30 	char *p;
31 	enum { T_EXACT=0, T_BASENAME, T_DIRECTORY } type;
32 	struct lm_list lml;
33 	TAILQ_ENTRY(lmp) lmp_link;
34 };
35 
36 static TAILQ_HEAD(lmc_list, lmc) lmc_head = TAILQ_HEAD_INITIALIZER(lmc_head);
37 struct lmc {
38 	char *path;
39 	dev_t dev;
40 	ino_t ino;
41 	TAILQ_ENTRY(lmc) next;
42 };
43 
44 static int lm_count;
45 
46 static void lmc_parse(char *, size_t);
47 static void lmc_parse_file(const char *);
48 static void lmc_parse_dir(const char *);
49 static void lm_add(const char *, const char *, const char *);
50 static void lm_free(struct lm_list *);
51 static char *lml_find(struct lm_list *, const char *);
52 static struct lm_list *lmp_find(const char *);
53 static struct lm_list *lmp_init(char *);
54 static const char *quickbasename(const char *);
55 
56 #define	iseol(c)	(((c) == '#') || ((c) == '\0') || \
57 			 ((c) == '\n') || ((c) == '\r'))
58 
59 /*
60  * Do not use ctype.h macros, which rely on working TLS.  It is
61  * too early to have thread-local variables functional.
62  */
63 #define	rtld_isspace(c)	((c) == ' ' || (c) == '\t')
64 
65 int
66 lm_init(char *libmap_override)
67 {
68 	char *p;
69 
70 	dbg("lm_init(\"%s\")", libmap_override);
71 	TAILQ_INIT(&lmp_head);
72 
73 	lmc_parse_file(ld_path_libmap_conf);
74 
75 	if (libmap_override) {
76 		/*
77 		 * Do some character replacement to make $LDLIBMAP look
78 		 * like a text file, then parse it.
79 		 */
80 		libmap_override = xstrdup(libmap_override);
81 		for (p = libmap_override; *p; p++) {
82 			switch (*p) {
83 			case '=':
84 				*p = ' ';
85 				break;
86 			case ',':
87 				*p = '\n';
88 				break;
89 			}
90 		}
91 		lmc_parse(libmap_override, p - libmap_override);
92 		free(libmap_override);
93 	}
94 
95 	return (lm_count == 0);
96 }
97 
98 static void
99 lmc_parse_file(const char *path)
100 {
101 	struct lmc *p;
102 	char *lm_map;
103 	struct stat st;
104 	ssize_t retval;
105 	int fd;
106 
107 	TAILQ_FOREACH(p, &lmc_head, next) {
108 		if (strcmp(p->path, path) == 0)
109 			return;
110 	}
111 
112 	fd = open(path, O_RDONLY | O_CLOEXEC);
113 	if (fd == -1) {
114 		dbg("lm_parse_file: open(\"%s\") failed, %s", path,
115 		    rtld_strerror(errno));
116 		return;
117 	}
118 	if (fstat(fd, &st) == -1) {
119 		close(fd);
120 		dbg("lm_parse_file: fstat(\"%s\") failed, %s", path,
121 		    rtld_strerror(errno));
122 		return;
123 	}
124 
125 	TAILQ_FOREACH(p, &lmc_head, next) {
126 		if (p->dev == st.st_dev && p->ino == st.st_ino) {
127 			close(fd);
128 			return;
129 		}
130 	}
131 
132 	lm_map = xmalloc(st.st_size);
133 	retval = read(fd, lm_map, st.st_size);
134 	if (retval != st.st_size) {
135 		close(fd);
136 		free(lm_map);
137 		dbg("lm_parse_file: read(\"%s\") failed, %s", path,
138 		    rtld_strerror(errno));
139 		return;
140 	}
141 	close(fd);
142 	p = xmalloc(sizeof(struct lmc));
143 	p->path = xstrdup(path);
144 	p->dev = st.st_dev;
145 	p->ino = st.st_ino;
146 	TAILQ_INSERT_HEAD(&lmc_head, p, next);
147 	lmc_parse(lm_map, st.st_size);
148 	free(lm_map);
149 }
150 
151 static void
152 lmc_parse_dir(const char *idir)
153 {
154 	DIR *d;
155 	struct dirent *dp;
156 	struct lmc *p;
157 	char conffile[MAXPATHLEN];
158 	char *ext;
159 
160 	TAILQ_FOREACH(p, &lmc_head, next) {
161 		if (strcmp(p->path, idir) == 0)
162 			return;
163 	}
164 	d = opendir(idir);
165 	if (d == NULL)
166 		return;
167 
168 	p = xmalloc(sizeof(struct lmc));
169 	p->path = xstrdup(idir);
170 	p->dev = NODEV;
171 	p->ino = 0;
172 	TAILQ_INSERT_HEAD(&lmc_head, p, next);
173 
174 	while ((dp = readdir(d)) != NULL) {
175 		if (dp->d_ino == 0)
176 			continue;
177 		if (dp->d_type != DT_REG)
178 			continue;
179 		ext = strrchr(dp->d_name, '.');
180 		if (ext == NULL)
181 			continue;
182 		if (strcmp(ext, ".conf") != 0)
183 			continue;
184 		if (strlcpy(conffile, idir, MAXPATHLEN) >= MAXPATHLEN)
185 			continue; /* too long */
186 		if (strlcat(conffile, "/", MAXPATHLEN) >= MAXPATHLEN)
187 			continue; /* too long */
188 		if (strlcat(conffile, dp->d_name, MAXPATHLEN) >= MAXPATHLEN)
189 			continue; /* too long */
190 		lmc_parse_file(conffile);
191 	}
192 	closedir(d);
193 }
194 
195 static void
196 lmc_parse(char *lm_p, size_t lm_len)
197 {
198 	char *cp, *f, *t, *c, *p;
199 	char prog[MAXPATHLEN];
200 	/* allow includedir + full length path */
201 	char line[MAXPATHLEN + 13];
202 	size_t cnt, i;
203 
204 	cnt = 0;
205 	p = NULL;
206 	while (cnt < lm_len) {
207 		i = 0;
208 		while (cnt < lm_len && lm_p[cnt] != '\n' &&
209 		    i < sizeof(line) - 1) {
210 			line[i] = lm_p[cnt];
211 			cnt++;
212 			i++;
213 		}
214 		line[i] = '\0';
215 		while (cnt < lm_len && lm_p[cnt] != '\n')
216 			cnt++;
217 		/* skip over nl */
218 		cnt++;
219 
220 		cp = &line[0];
221 		t = f = c = NULL;
222 
223 		/* Skip over leading space */
224 		while (rtld_isspace(*cp))
225 			cp++;
226 
227 		/* Found a comment or EOL */
228 		if (iseol(*cp))
229 			continue;
230 
231 		/* Found a constraint selector */
232 		if (*cp == '[') {
233 			cp++;
234 
235 			/* Skip leading space */
236 			while (rtld_isspace(*cp))
237 				cp++;
238 
239 			/* Found comment, EOL or end of selector */
240 			if  (iseol(*cp) || *cp == ']')
241 				continue;
242 
243 			c = cp++;
244 			/* Skip to end of word */
245 			while (!rtld_isspace(*cp) && !iseol(*cp) && *cp != ']')
246 				cp++;
247 
248 			/* Skip and zero out trailing space */
249 			while (rtld_isspace(*cp))
250 				*cp++ = '\0';
251 
252 			/* Check if there is a closing brace */
253 			if (*cp != ']')
254 				continue;
255 
256 			/* Terminate string if there was no trailing space */
257 			*cp++ = '\0';
258 
259 			/*
260 			 * There should be nothing except whitespace or comment
261 			  from this point to the end of the line.
262 			 */
263 			while (rtld_isspace(*cp))
264 				cp++;
265 			if (!iseol(*cp))
266 				continue;
267 
268 			if (strlcpy(prog, c, sizeof prog) >= sizeof prog)
269 				continue;
270 			p = prog;
271 			continue;
272 		}
273 
274 		/* Parse the 'from' candidate. */
275 		f = cp++;
276 		while (!rtld_isspace(*cp) && !iseol(*cp))
277 			cp++;
278 
279 		/* Skip and zero out the trailing whitespace */
280 		while (rtld_isspace(*cp))
281 			*cp++ = '\0';
282 
283 		/* Found a comment or EOL */
284 		if (iseol(*cp))
285 			continue;
286 
287 		/* Parse 'to' mapping */
288 		t = cp++;
289 		while (!rtld_isspace(*cp) && !iseol(*cp))
290 			cp++;
291 
292 		/* Skip and zero out the trailing whitespace */
293 		while (rtld_isspace(*cp))
294 			*cp++ = '\0';
295 
296 		/* Should be no extra tokens at this point */
297 		if (!iseol(*cp))
298 			continue;
299 
300 		*cp = '\0';
301 		if (strcmp(f, "includedir") == 0)
302 			lmc_parse_dir(t);
303 		else if (strcmp(f, "include") == 0)
304 			lmc_parse_file(t);
305 		else
306 			lm_add(p, f, t);
307 	}
308 }
309 
310 static void
311 lm_free(struct lm_list *lml)
312 {
313 	struct lm *lm;
314 
315 	dbg("%s(%p)", __func__, lml);
316 
317 	while (!TAILQ_EMPTY(lml)) {
318 		lm = TAILQ_FIRST(lml);
319 		TAILQ_REMOVE(lml, lm, lm_link);
320 		free(lm->f);
321 		free(lm->t);
322 		free(lm);
323 	}
324 }
325 
326 void
327 lm_fini(void)
328 {
329 	struct lmp *lmp;
330 	struct lmc *p;
331 
332 	dbg("%s()", __func__);
333 
334 	while (!TAILQ_EMPTY(&lmc_head)) {
335 		p = TAILQ_FIRST(&lmc_head);
336 		TAILQ_REMOVE(&lmc_head, p, next);
337 		free(p->path);
338 		free(p);
339 	}
340 
341 	while (!TAILQ_EMPTY(&lmp_head)) {
342 		lmp = TAILQ_FIRST(&lmp_head);
343 		TAILQ_REMOVE(&lmp_head, lmp, lmp_link);
344 		free(lmp->p);
345 		lm_free(&lmp->lml);
346 		free(lmp);
347 	}
348 }
349 
350 static void
351 lm_add(const char *p, const char *f, const char *t)
352 {
353 	struct lm_list *lml;
354 	struct lm *lm;
355 	const char *t1;
356 
357 	if (p == NULL)
358 		p = "$DEFAULT$";
359 
360 	dbg("%s(\"%s\", \"%s\", \"%s\")", __func__, p, f, t);
361 
362 	if ((lml = lmp_find(p)) == NULL)
363 		lml = lmp_init(xstrdup(p));
364 
365 	t1 = lml_find(lml, f);
366 	if (t1 == NULL || strcmp(t1, t) != 0) {
367 		lm = xmalloc(sizeof(struct lm));
368 		lm->f = xstrdup(f);
369 		lm->t = xstrdup(t);
370 		TAILQ_INSERT_HEAD(lml, lm, lm_link);
371 		lm_count++;
372 	}
373 }
374 
375 char *
376 lm_find(const char *p, const char *f)
377 {
378 	struct lm_list *lml;
379 	char *t;
380 
381 	dbg("%s(\"%s\", \"%s\")", __func__, p, f);
382 
383 	if (p != NULL && (lml = lmp_find(p)) != NULL) {
384 		t = lml_find(lml, f);
385 		if (t != NULL) {
386 			/*
387 			 * Add a global mapping if we have
388 			 * a successful constrained match.
389 			 */
390 			lm_add(NULL, f, t);
391 			return (t);
392 		}
393 	}
394 	lml = lmp_find("$DEFAULT$");
395 	if (lml != NULL)
396 		return (lml_find(lml, f));
397 	return (NULL);
398 }
399 
400 /*
401  * Given a libmap translation list and a library name, return the
402  * replacement library, or NULL.
403  */
404 char *
405 lm_findn(const char *p, const char *f, const size_t n)
406 {
407 	char pathbuf[64], *s, *t;
408 
409 	if (n < sizeof(pathbuf) - 1)
410 		s = pathbuf;
411 	else
412 		s = xmalloc(n + 1);
413 	memcpy(s, f, n);
414 	s[n] = '\0';
415 	t = lm_find(p, s);
416 	if (s != pathbuf)
417 		free(s);
418 	return (t);
419 }
420 
421 static char *
422 lml_find(struct lm_list *lmh, const char *f)
423 {
424 	struct lm *lm;
425 
426 	dbg("%s(%p, \"%s\")", __func__, lmh, f);
427 
428 	TAILQ_FOREACH(lm, lmh, lm_link) {
429 		if (strcmp(f, lm->f) == 0)
430 			return (lm->t);
431 	}
432 	return (NULL);
433 }
434 
435 /*
436  * Given an executable name, return a pointer to the translation list or
437  * NULL if no matches.
438  */
439 static struct lm_list *
440 lmp_find(const char *n)
441 {
442 	struct lmp *lmp;
443 
444 	dbg("%s(\"%s\")", __func__, n);
445 
446 	TAILQ_FOREACH(lmp, &lmp_head, lmp_link) {
447 		if ((lmp->type == T_EXACT && strcmp(n, lmp->p) == 0) ||
448 		    (lmp->type == T_DIRECTORY && strncmp(n, lmp->p,
449 		    strlen(lmp->p)) == 0) ||
450 		    (lmp->type == T_BASENAME && strcmp(quickbasename(n),
451 		    lmp->p) == 0))
452 			return (&lmp->lml);
453 	}
454 	return (NULL);
455 }
456 
457 static struct lm_list *
458 lmp_init(char *n)
459 {
460 	struct lmp *lmp;
461 
462 	dbg("%s(\"%s\")", __func__, n);
463 
464 	lmp = xmalloc(sizeof(struct lmp));
465 	lmp->p = n;
466 	if (n[strlen(n) - 1] == '/')
467 		lmp->type = T_DIRECTORY;
468 	else if (strchr(n,'/') == NULL)
469 		lmp->type = T_BASENAME;
470 	else
471 		lmp->type = T_EXACT;
472 	TAILQ_INIT(&lmp->lml);
473 	TAILQ_INSERT_HEAD(&lmp_head, lmp, lmp_link);
474 
475 	return (&lmp->lml);
476 }
477 
478 /*
479  * libc basename is overkill.  Return a pointer to the character after
480  * the last /, or the original string if there are no slashes.
481  */
482 static const char *
483 quickbasename(const char *path)
484 {
485 	const char *p;
486 
487 	for (p = path; *path != '\0'; path++) {
488 		if (*path == '/')
489 			p = path + 1;
490 	}
491 	return (p);
492 }
493