1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1998 John D. Polstra
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/endian.h>
31 #include <sys/mman.h>
32 #include <sys/stat.h>
33
34 #include <ctype.h>
35 #include <dirent.h>
36 #include <elf-hints.h>
37 #include <err.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44
45 #include "ldconfig.h"
46
47 #define MAXDIRS 1024 /* Maximum directories in path */
48 #define MAXFILESIZE (16*1024) /* Maximum hints file size */
49
50 static void add_dir(const char *, const char *, bool);
51 static void read_dirs_from_file(const char *, const char *);
52 static void read_elf_hints(const char *, bool, bool);
53 static void write_elf_hints(const char *);
54
55 static const char *dirs[MAXDIRS];
56 static int ndirs;
57 static bool is_be;
58 bool insecure;
59
60 static void
add_dir(const char * hintsfile,const char * name,bool trusted)61 add_dir(const char *hintsfile, const char *name, bool trusted)
62 {
63 struct stat stbuf;
64 int i;
65
66 /* Do some security checks */
67 if (!trusted && !insecure) {
68 if (stat(name, &stbuf) == -1) {
69 warn("%s", name);
70 return;
71 }
72 if (stbuf.st_uid != 0) {
73 warnx("%s: ignoring directory not owned by root", name);
74 return;
75 }
76 if ((stbuf.st_mode & S_IWOTH) != 0) {
77 warnx("%s: ignoring world-writable directory", name);
78 return;
79 }
80 if ((stbuf.st_mode & S_IWGRP) != 0) {
81 warnx("%s: ignoring group-writable directory", name);
82 return;
83 }
84 }
85
86 for (i = 0; i < ndirs; i++)
87 if (strcmp(dirs[i], name) == 0)
88 return;
89 if (ndirs >= MAXDIRS)
90 errx(1, "\"%s\": Too many directories in path", hintsfile);
91 dirs[ndirs++] = name;
92 }
93
94 void
list_elf_hints(const char * hintsfile)95 list_elf_hints(const char *hintsfile)
96 {
97 int i;
98 int nlibs;
99
100 read_elf_hints(hintsfile, true, false);
101 printf("%s:\n", hintsfile);
102 printf("\tsearch directories:");
103 for (i = 0; i < ndirs; i++)
104 printf("%c%s", i == 0 ? ' ' : ':', dirs[i]);
105 printf("\n");
106
107 nlibs = 0;
108 for (i = 0; i < ndirs; i++) {
109 DIR *dirp;
110 struct dirent *dp;
111
112 if ((dirp = opendir(dirs[i])) == NULL)
113 continue;
114 while ((dp = readdir(dirp)) != NULL) {
115 int len;
116 int namelen;
117 const char *name;
118 const char *vers;
119
120 /* Name can't be shorter than "libx.so.0" */
121 if ((len = strlen(dp->d_name)) < 9 ||
122 strncmp(dp->d_name, "lib", 3) != 0)
123 continue;
124 name = dp->d_name + 3;
125 vers = dp->d_name + len;
126 while (vers > dp->d_name && isdigit(*(vers-1)))
127 vers--;
128 if (vers == dp->d_name + len)
129 continue;
130 if (vers < dp->d_name + 4 ||
131 strncmp(vers - 4, ".so.", 4) != 0)
132 continue;
133
134 /* We have a valid shared library name. */
135 namelen = (vers - 4) - name;
136 printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs,
137 namelen, name, vers, dirs[i], dp->d_name);
138 nlibs++;
139 }
140 closedir(dirp);
141 }
142 }
143
144 static void
read_dirs_from_file(const char * hintsfile,const char * listfile)145 read_dirs_from_file(const char *hintsfile, const char *listfile)
146 {
147 FILE *fp;
148 char buf[MAXPATHLEN];
149 int linenum;
150
151 if ((fp = fopen(listfile, "r")) == NULL)
152 err(1, "%s", listfile);
153
154 linenum = 0;
155 while (fgets(buf, sizeof buf, fp) != NULL) {
156 char *cp, *sp;
157
158 linenum++;
159 cp = buf;
160 /* Skip leading white space. */
161 while (isspace(*cp))
162 cp++;
163 if (*cp == '#' || *cp == '\0')
164 continue;
165 sp = cp;
166 /* Advance over the directory name. */
167 while (!isspace(*cp) && *cp != '\0')
168 cp++;
169 /* Terminate the string and skip trailing white space. */
170 if (*cp != '\0') {
171 *cp++ = '\0';
172 while (isspace(*cp))
173 cp++;
174 }
175 /* Now we had better be at the end of the line. */
176 if (*cp != '\0')
177 warnx("%s:%d: trailing characters ignored",
178 listfile, linenum);
179
180 if ((sp = strdup(sp)) == NULL)
181 errx(1, "Out of memory");
182 add_dir(hintsfile, sp, 0);
183 }
184
185 fclose(fp);
186 }
187
188 /* Convert between native byte order and forced little resp. big endian. */
189 #define COND_SWAP(n) (is_be ? be32toh(n) : le32toh(n))
190
191 static void
read_elf_hints(const char * hintsfile,bool must_exist,bool force_be)192 read_elf_hints(const char *hintsfile, bool must_exist, bool force_be)
193 {
194 int fd;
195 struct stat s;
196 void *mapbase;
197 struct elfhints_hdr *hdr;
198 char *strtab;
199 char *dirlist;
200 char *p;
201 int hdr_version;
202
203 if ((fd = open(hintsfile, O_RDONLY)) == -1) {
204 if (errno == ENOENT && !must_exist)
205 return;
206 err(1, "Cannot open \"%s\"", hintsfile);
207 }
208 if (fstat(fd, &s) == -1)
209 err(1, "Cannot stat \"%s\"", hintsfile);
210 if (s.st_size > MAXFILESIZE)
211 errx(1, "\"%s\" is unreasonably large", hintsfile);
212 /*
213 * We use a read-write, private mapping so that we can null-terminate
214 * some strings in it without affecting the underlying file.
215 */
216 mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE,
217 MAP_PRIVATE, fd, 0);
218 if (mapbase == MAP_FAILED)
219 err(1, "Cannot mmap \"%s\"", hintsfile);
220 close(fd);
221
222 hdr = (struct elfhints_hdr *)mapbase;
223 is_be = hdr->magic == htobe32(ELFHINTS_MAGIC);
224 if (COND_SWAP(hdr->magic) != ELFHINTS_MAGIC)
225 errx(1, "\"%s\": invalid file format", hintsfile);
226 if (force_be && !is_be)
227 errx(1, "\"%s\": incompatible endianness requested", hintsfile);
228 hdr_version = COND_SWAP(hdr->version);
229 if (hdr_version != 1)
230 errx(1, "\"%s\": unrecognized file version (%d)", hintsfile,
231 hdr_version);
232
233 strtab = (char *)mapbase + COND_SWAP(hdr->strtab);
234 dirlist = strtab + COND_SWAP(hdr->dirlist);
235
236 if (*dirlist != '\0')
237 while ((p = strsep(&dirlist, ":")) != NULL)
238 add_dir(hintsfile, p, 1);
239 }
240
241 void
update_elf_hints(const char * hintsfile,int argc,char ** argv,bool merge,bool force_be)242 update_elf_hints(const char *hintsfile, int argc, char **argv, bool merge,
243 bool force_be)
244 {
245 struct stat s;
246 int i;
247
248 /*
249 * Create little-endian hints files on all architectures unless
250 * ldconfig has been invoked with the -B option.
251 */
252 is_be = force_be;
253 if (merge)
254 read_elf_hints(hintsfile, false, force_be);
255 for (i = 0; i < argc; i++) {
256 if (stat(argv[i], &s) == -1)
257 warn("warning: %s", argv[i]);
258 else if (S_ISREG(s.st_mode))
259 read_dirs_from_file(hintsfile, argv[i]);
260 else
261 add_dir(hintsfile, argv[i], 0);
262 }
263 write_elf_hints(hintsfile);
264 }
265
266 static void
write_elf_hints(const char * hintsfile)267 write_elf_hints(const char *hintsfile)
268 {
269 struct elfhints_hdr hdr;
270 char *tempname;
271 int fd;
272 FILE *fp;
273 int i;
274
275 if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1)
276 errx(1, "Out of memory");
277 if ((fd = mkstemp(tempname)) == -1)
278 err(1, "mkstemp(%s)", tempname);
279 if (fchmod(fd, 0444) == -1)
280 err(1, "fchmod(%s)", tempname);
281 if ((fp = fdopen(fd, "wb")) == NULL)
282 err(1, "fdopen(%s)", tempname);
283
284 hdr.magic = COND_SWAP(ELFHINTS_MAGIC);
285 hdr.version = COND_SWAP(1);
286 hdr.strtab = COND_SWAP(sizeof hdr);
287 hdr.strsize = 0;
288 hdr.dirlist = 0;
289 memset(hdr.spare, 0, sizeof hdr.spare);
290
291 /* Count up the size of the string table. */
292 if (ndirs > 0) {
293 hdr.strsize += strlen(dirs[0]);
294 for (i = 1; i < ndirs; i++)
295 hdr.strsize += 1 + strlen(dirs[i]);
296 }
297 hdr.dirlistlen = COND_SWAP(hdr.strsize);
298 hdr.strsize++; /* For the null terminator */
299 /* convert in-place from native to target endianness */
300 hdr.strsize = COND_SWAP(hdr.strsize);
301
302 /* Write the header. */
303 if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr)
304 err(1, "%s: write error", tempname);
305 /* Write the strings. */
306 if (ndirs > 0) {
307 if (fputs(dirs[0], fp) == EOF)
308 err(1, "%s: write error", tempname);
309 for (i = 1; i < ndirs; i++)
310 if (fprintf(fp, ":%s", dirs[i]) < 0)
311 err(1, "%s: write error", tempname);
312 }
313 if (putc('\0', fp) == EOF || fclose(fp) == EOF)
314 err(1, "%s: write error", tempname);
315
316 if (rename(tempname, hintsfile) == -1)
317 err(1, "rename %s to %s", tempname, hintsfile);
318 free(tempname);
319 }
320