xref: /freebsd/libexec/rtld-elf/libmap.c (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
1 /*
2  * $FreeBSD$
3  */
4 
5 #include <stdio.h>
6 #include <ctype.h>
7 #include <string.h>
8 #include <stdlib.h>
9 #include <sys/queue.h>
10 #include <sys/param.h>
11 
12 #include "debug.h"
13 #include "rtld.h"
14 #include "libmap.h"
15 
16 #ifndef _PATH_LIBMAP_CONF
17 #define	_PATH_LIBMAP_CONF	"/etc/libmap.conf"
18 #endif
19 
20 #ifdef COMPAT_32BIT
21 #undef _PATH_LIBMAP_CONF
22 #define	_PATH_LIBMAP_CONF	"/etc/libmap32.conf"
23 #endif
24 
25 TAILQ_HEAD(lm_list, lm);
26 struct lm {
27 	char *f;
28 	char *t;
29 
30 	TAILQ_ENTRY(lm)	lm_link;
31 };
32 
33 TAILQ_HEAD(lmp_list, lmp) lmp_head = TAILQ_HEAD_INITIALIZER(lmp_head);
34 struct lmp {
35 	char *p;
36 	enum { T_EXACT=0, T_BASENAME, T_DIRECTORY } type;
37 	struct lm_list lml;
38 	TAILQ_ENTRY(lmp) lmp_link;
39 };
40 
41 static void		lm_add		(const char *, const char *, const char *);
42 static void		lm_free		(struct lm_list *);
43 static char *		lml_find	(struct lm_list *, const char *);
44 static struct lm_list *	lmp_find	(const char *);
45 static struct lm_list *	lmp_init	(char *);
46 static const char * quickbasename	(const char *);
47 
48 #define	iseol(c)	(((c) == '#') || ((c) == '\0') || \
49 			 ((c) == '\n') || ((c) == '\r'))
50 
51 int
52 lm_init (void)
53 {
54 	FILE	*fp;
55 	char	*cp;
56 	char	*f, *t, *p, *c;
57 	char	prog[MAXPATHLEN];
58 	char	line[MAXPATHLEN + 2];
59 
60 	dbg("%s()", __func__);
61 
62 	TAILQ_INIT(&lmp_head);
63 
64 	if ((fp = fopen(_PATH_LIBMAP_CONF, "r")) == NULL)
65 		return (1);
66 
67 	p = NULL;
68 	while ((cp = fgets(line, MAXPATHLEN + 1, fp)) != NULL) {
69 		t = f = c = NULL;
70 
71 		/* Skip over leading space */
72 		while (isspace(*cp)) cp++;
73 
74 		/* Found a comment or EOL */
75 		if (iseol(*cp)) continue;
76 
77 		/* Found a constraint selector */
78 		if (*cp == '[') {
79 			cp++;
80 
81 			/* Skip leading space */
82 			while (isspace(*cp)) cp++;
83 
84 			/* Found comment, EOL or end of selector */
85 			if  (iseol(*cp) || *cp == ']')
86 				continue;
87 
88 			c = cp++;
89 			/* Skip to end of word */
90 			while (!isspace(*cp) && !iseol(*cp) && *cp != ']')
91 				cp++;
92 
93 			/* Skip and zero out trailing space */
94 			while (isspace(*cp)) *cp++ = '\0';
95 
96 			/* Check if there is a closing brace */
97 			if (*cp != ']') continue;
98 
99 			/* Terminate string if there was no trailing space */
100 			*cp++ = '\0';
101 
102 			/*
103 			 * There should be nothing except whitespace or comment
104 			  from this point to the end of the line.
105 			 */
106 			while(isspace(*cp)) cp++;
107 			if (!iseol(*cp)) continue;
108 
109 			strcpy(prog, c);
110 			p = prog;
111 			continue;
112 		}
113 
114 		/* Parse the 'from' candidate. */
115 		f = cp++;
116 		while (!isspace(*cp) && !iseol(*cp)) cp++;
117 
118 		/* Skip and zero out the trailing whitespace */
119 		while (isspace(*cp)) *cp++ = '\0';
120 
121 		/* Found a comment or EOL */
122 		if (iseol(*cp)) continue;
123 
124 		/* Parse 'to' mapping */
125 		t = cp++;
126 		while (!isspace(*cp) && !iseol(*cp)) cp++;
127 
128 		/* Skip and zero out the trailing whitespace */
129 		while (isspace(*cp)) *cp++ = '\0';
130 
131 		/* Should be no extra tokens at this point */
132 		if (!iseol(*cp)) continue;
133 
134 		*cp = '\0';
135 		lm_add(p, f, t);
136 	}
137 	fclose(fp);
138 	return (0);
139 }
140 
141 static void
142 lm_free (struct lm_list *lml)
143 {
144 	struct lm *lm;
145 
146 	dbg("%s(%p)", __func__, lml);
147 
148 	while (!TAILQ_EMPTY(lml)) {
149 		lm = TAILQ_FIRST(lml);
150 		TAILQ_REMOVE(lml, lm, lm_link);
151 		free(lm->f);
152 		free(lm->t);
153 		free(lm);
154 	}
155 	return;
156 }
157 
158 void
159 lm_fini (void)
160 {
161 	struct lmp *lmp;
162 
163 	dbg("%s()", __func__);
164 
165 	while (!TAILQ_EMPTY(&lmp_head)) {
166 		lmp = TAILQ_FIRST(&lmp_head);
167 		TAILQ_REMOVE(&lmp_head, lmp, lmp_link);
168 		free(lmp->p);
169 		lm_free(&lmp->lml);
170 		free(lmp);
171 	}
172 	return;
173 }
174 
175 static void
176 lm_add (const char *p, const char *f, const char *t)
177 {
178 	struct lm_list *lml;
179 	struct lm *lm;
180 
181 	if (p == NULL)
182 		p = "$DEFAULT$";
183 
184 	dbg("%s(\"%s\", \"%s\", \"%s\")", __func__, p, f, t);
185 
186 	if ((lml = lmp_find(p)) == NULL)
187 		lml = lmp_init(xstrdup(p));
188 
189 	lm = xmalloc(sizeof(struct lm));
190 	lm->f = xstrdup(f);
191 	lm->t = xstrdup(t);
192 	TAILQ_INSERT_HEAD(lml, lm, lm_link);
193 }
194 
195 char *
196 lm_find (const char *p, const char *f)
197 {
198 	struct lm_list *lml;
199 	char *t;
200 
201 	dbg("%s(\"%s\", \"%s\")", __func__, p, f);
202 
203 	if (p != NULL && (lml = lmp_find(p)) != NULL) {
204 		t = lml_find(lml, f);
205 		if (t != NULL) {
206 			/*
207 			 * Add a global mapping if we have
208 			 * a successful constrained match.
209 			 */
210 			lm_add(NULL, f, t);
211 			return (t);
212 		}
213 	}
214 	lml = lmp_find("$DEFAULT$");
215 	if (lml != NULL)
216 		return (lml_find(lml, f));
217 	else
218 		return (NULL);
219 }
220 
221 /* Given a libmap translation list and a library name, return the
222    replacement library, or NULL */
223 #ifdef COMPAT_32BIT
224 char *
225 lm_findn (const char *p, const char *f, const int n)
226 {
227 	char pathbuf[64], *s, *t;
228 
229 	if (n < sizeof(pathbuf) - 1) {
230 		memcpy(pathbuf, f, n);
231 		pathbuf[n] = '\0';
232 		s = pathbuf;
233 	} else {
234 		s = xmalloc(n + 1);
235 		strcpy(s, f);
236 	}
237 	t = lm_find(p, s);
238 	if (s != pathbuf)
239 		free(s);
240 	return (t);
241 }
242 #endif
243 
244 static char *
245 lml_find (struct lm_list *lmh, const char *f)
246 {
247 	struct lm *lm;
248 
249 	dbg("%s(%p, \"%s\")", __func__, lmh, f);
250 
251 	TAILQ_FOREACH(lm, lmh, lm_link)
252 		if (strcmp(f, lm->f) == 0)
253 			return (lm->t);
254 	return NULL;
255 }
256 
257 /* Given an executable name, return a pointer to the translation list or
258    NULL if no matches */
259 static struct lm_list *
260 lmp_find (const char *n)
261 {
262 	struct lmp *lmp;
263 
264 	dbg("%s(\"%s\")", __func__, n);
265 
266 	TAILQ_FOREACH(lmp, &lmp_head, lmp_link)
267 		if ((lmp->type == T_EXACT && strcmp(n, lmp->p) == 0) ||
268 		    (lmp->type == T_DIRECTORY && strncmp(n, lmp->p, strlen(lmp->p)) == 0) ||
269 		    (lmp->type == T_BASENAME && strcmp(quickbasename(n), lmp->p) == 0))
270 			return (&lmp->lml);
271 	return (NULL);
272 }
273 
274 static struct lm_list *
275 lmp_init (char *n)
276 {
277 	struct lmp *lmp;
278 
279 	dbg("%s(\"%s\")", __func__, n);
280 
281 	lmp = xmalloc(sizeof(struct lmp));
282 	lmp->p = n;
283 	if (n[strlen(n)-1] == '/')
284 		lmp->type = T_DIRECTORY;
285 	else if (strchr(n,'/') == NULL)
286 		lmp->type = T_BASENAME;
287 	else
288 		lmp->type = T_EXACT;
289 	TAILQ_INIT(&lmp->lml);
290 	TAILQ_INSERT_HEAD(&lmp_head, lmp, lmp_link);
291 
292 	return (&lmp->lml);
293 }
294 
295 /* libc basename is overkill.  Return a pointer to the character after the
296    last /, or the original string if there are no slashes. */
297 static const char *
298 quickbasename (const char *path)
299 {
300 	const char *p = path;
301 	for (; *path; path++)
302 	{
303 		if (*path == '/')
304 			p = path+1;
305 	}
306 	return p;
307 }
308