elfhints.c revision 64360
1/*-
2 * Copyright (c) 1998 John D. Polstra
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sbin/ldconfig/elfhints.c 64360 2000-08-07 19:12:04Z jdp $
27 */
28
29#include <sys/param.h>
30#include <sys/mman.h>
31#include <sys/stat.h>
32
33#include <ctype.h>
34#include <dirent.h>
35#include <elf.h>
36#include <err.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <unistd.h>
43
44#include "ldconfig.h"
45
46#define MAXDIRS		1024		/* Maximum directories in path */
47#define MAXFILESIZE	(16*1024)	/* Maximum hints file size */
48
49static void	add_dir(const char *, const char *, int);
50static void	read_dirs_from_file(const char *, const char *);
51static void	read_elf_hints(const char *, int);
52static void	write_elf_hints(const char *);
53
54static const char	*dirs[MAXDIRS];
55static int		 ndirs;
56
57static void
58add_dir(const char *hintsfile, const char *name, int trusted)
59{
60	struct stat 	stbuf;
61	int		i;
62
63	/* Do some security checks */
64	if (!trusted && !insecure) {
65		if (stat(name, &stbuf) == -1) {
66			warn("%s", name);
67			return;
68		}
69		if (stbuf.st_uid != 0) {
70			warnx("%s: ignoring directory not owned by root", name);
71			return;
72		}
73		if ((stbuf.st_mode & S_IWOTH) != 0) {
74			warnx("%s: ignoring world-writable directory", name);
75			return;
76		}
77	}
78
79	for (i = 0;  i < ndirs;  i++)
80		if (strcmp(dirs[i], name) == 0)
81			return;
82	if (ndirs >= MAXDIRS)
83		errx(1, "\"%s\": Too many directories in path", hintsfile);
84	dirs[ndirs++] = name;
85}
86
87void
88list_elf_hints(const char *hintsfile)
89{
90	int	i;
91	int	nlibs;
92
93	read_elf_hints(hintsfile, 1);
94	printf("%s:\n", hintsfile);
95	printf("\tsearch directories:");
96	for (i = 0;  i < ndirs;  i++)
97		printf("%c%s", i == 0 ? ' ' : ':', dirs[i]);
98	printf("\n");
99
100	nlibs = 0;
101	for (i = 0;  i < ndirs;  i++) {
102		DIR		*dirp;
103		struct dirent	*dp;
104
105		if ((dirp = opendir(dirs[i])) == NULL)
106			continue;
107		while ((dp = readdir(dirp)) != NULL) {
108			int		 len;
109			int		 namelen;
110			const char	*name;
111			const char	*vers;
112
113			/* Name can't be shorter than "libx.so.0" */
114			if ((len = strlen(dp->d_name)) < 9 ||
115			    strncmp(dp->d_name, "lib", 3) != 0)
116				continue;
117			name = dp->d_name + 3;
118			vers = dp->d_name + len;
119			while (vers > dp->d_name && isdigit(*(vers-1)))
120				vers--;
121			if (vers == dp->d_name + len)
122				continue;
123			if (vers < dp->d_name + 4 ||
124			    strncmp(vers - 4, ".so.", 4) != 0)
125				continue;
126
127			/* We have a valid shared library name. */
128			namelen = (vers - 4) - name;
129			printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs,
130			    namelen, name, vers, dirs[i], dp->d_name);
131			nlibs++;
132		}
133		closedir(dirp);
134	}
135}
136
137static void
138read_dirs_from_file(const char *hintsfile, const char *listfile)
139{
140	FILE	*fp;
141	char	 buf[MAXPATHLEN];
142	int	 linenum;
143
144	if ((fp = fopen(listfile, "r")) == NULL)
145		err(1, "%s", listfile);
146
147	linenum = 0;
148	while (fgets(buf, sizeof buf, fp) != NULL) {
149		char	*cp, *sp;
150
151		linenum++;
152		cp = buf;
153		/* Skip leading white space. */
154		while (isspace(*cp))
155			cp++;
156		if (*cp == '#' || *cp == '\0')
157			continue;
158		sp = cp;
159		/* Advance over the directory name. */
160		while (!isspace(*cp) && *cp != '\0')
161			cp++;
162		/* Terminate the string and skip trailing white space. */
163		if (*cp != '\0') {
164			*cp++ = '\0';
165			while (isspace(*cp))
166				cp++;
167		}
168		/* Now we had better be at the end of the line. */
169		if (*cp != '\0')
170			warnx("%s:%d: trailing characters ignored",
171			    listfile, linenum);
172
173		if ((sp = strdup(sp)) == NULL)
174			errx(1, "Out of memory");
175		add_dir(hintsfile, sp, 0);
176	}
177
178	fclose(fp);
179}
180
181static void
182read_elf_hints(const char *hintsfile, int must_exist)
183{
184	int	 		 fd;
185	struct stat		 s;
186	void			*mapbase;
187	struct elfhints_hdr	*hdr;
188	char			*strtab;
189	char			*dirlist;
190	char			*p;
191
192	if ((fd = open(hintsfile, O_RDONLY)) == -1) {
193		if (errno == ENOENT && !must_exist)
194			return;
195		err(1, "Cannot open \"%s\"", hintsfile);
196	}
197	if (fstat(fd, &s) == -1)
198		err(1, "Cannot stat \"%s\"", hintsfile);
199	if (s.st_size > MAXFILESIZE)
200		errx(1, "\"%s\" is unreasonably large", hintsfile);
201	/*
202	 * We use a read-write, private mapping so that we can null-terminate
203	 * some strings in it without affecting the underlying file.
204	 */
205	mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE,
206	    MAP_PRIVATE, fd, 0);
207	if (mapbase == MAP_FAILED)
208		err(1, "Cannot mmap \"%s\"", hintsfile);
209	close(fd);
210
211	hdr = (struct elfhints_hdr *)mapbase;
212	if (hdr->magic != ELFHINTS_MAGIC)
213		errx(1, "\"%s\": invalid file format", hintsfile);
214	if (hdr->version != 1)
215		errx(1, "\"%s\": unrecognized file version (%d)", hintsfile,
216		    hdr->version);
217
218	strtab = (char *)mapbase + hdr->strtab;
219	dirlist = strtab + hdr->dirlist;
220
221	if (*dirlist != '\0')
222		while ((p = strsep(&dirlist, ":")) != NULL)
223			add_dir(hintsfile, p, 1);
224}
225
226void
227update_elf_hints(const char *hintsfile, int argc, char **argv, int merge)
228{
229	int	i;
230
231	if (merge)
232		read_elf_hints(hintsfile, 0);
233	for (i = 0;  i < argc;  i++) {
234		struct stat	s;
235
236		if (stat(argv[i], &s) == -1)
237			warn("warning: %s", argv[i]);
238		else if (S_ISREG(s.st_mode))
239			read_dirs_from_file(hintsfile, argv[i]);
240		else
241			add_dir(hintsfile, argv[i], 0);
242	}
243	write_elf_hints(hintsfile);
244}
245
246static void
247write_elf_hints(const char *hintsfile)
248{
249	struct elfhints_hdr	 hdr;
250	char			*tempname;
251	int			 fd;
252	FILE			*fp;
253	int			 i;
254
255	if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1)
256		errx(1, "Out of memory");
257	if ((fd = mkstemp(tempname)) ==  -1)
258		err(1, "mkstemp(%s)", tempname);
259	if (fchmod(fd, 0444) == -1)
260		err(1, "fchmod(%s)", tempname);
261	if ((fp = fdopen(fd, "wb")) == NULL)
262		err(1, "fdopen(%s)", tempname);
263
264	hdr.magic = ELFHINTS_MAGIC;
265	hdr.version = 1;
266	hdr.strtab = sizeof hdr;
267	hdr.strsize = 0;
268	hdr.dirlist = 0;
269	memset(hdr.spare, 0, sizeof hdr.spare);
270
271	/* Count up the size of the string table. */
272	if (ndirs > 0) {
273		hdr.strsize += strlen(dirs[0]);
274		for (i = 1;  i < ndirs;  i++)
275			hdr.strsize += 1 + strlen(dirs[i]);
276	}
277	hdr.dirlistlen = hdr.strsize;
278	hdr.strsize++;	/* For the null terminator */
279
280	/* Write the header. */
281	if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr)
282		err(1, "%s: write error", tempname);
283	/* Write the strings. */
284	if (ndirs > 0) {
285		if (fputs(dirs[0], fp) == EOF)
286			err(1, "%s: write error", tempname);
287		for (i = 1;  i < ndirs;  i++)
288			if (fprintf(fp, ":%s", dirs[i]) < 0)
289				err(1, "%s: write error", tempname);
290	}
291	if (putc('\0', fp) == EOF || fclose(fp) == EOF)
292		err(1, "%s: write error", tempname);
293
294	if (rename(tempname, hintsfile) == -1)
295		err(1, "rename %s to %s", tempname, hintsfile);
296	free(tempname);
297}
298