elfhints.c revision 63872
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 63872 2000-07-26 04:47:17Z 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 *); 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) 59{ 60 struct stat stbuf; 61 int i; 62 63 /* Do some security checks */ 64 if (stat(name, &stbuf) == -1) { 65 warn("%s", name); 66 return; 67 } 68 if (stbuf.st_uid != 0) { 69 warnx("%s: not owned by root", name); 70 return; 71 } 72 if ((stbuf.st_mode & S_IWOTH) != 0) { 73 warnx("%s: ignoring world-writable directory", name); 74 return; 75 } 76 77 for (i = 0; i < ndirs; i++) 78 if (strcmp(dirs[i], name) == 0) 79 return; 80 if (ndirs >= MAXDIRS) 81 errx(1, "\"%s\": Too many directories in path", hintsfile); 82 dirs[ndirs++] = name; 83} 84 85void 86list_elf_hints(const char *hintsfile) 87{ 88 int i; 89 int nlibs; 90 91 read_elf_hints(hintsfile, 1); 92 printf("%s:\n", hintsfile); 93 printf("\tsearch directories:"); 94 for (i = 0; i < ndirs; i++) 95 printf("%c%s", i == 0 ? ' ' : ':', dirs[i]); 96 printf("\n"); 97 98 nlibs = 0; 99 for (i = 0; i < ndirs; i++) { 100 DIR *dirp; 101 struct dirent *dp; 102 103 if ((dirp = opendir(dirs[i])) == NULL) 104 continue; 105 while ((dp = readdir(dirp)) != NULL) { 106 int len; 107 int namelen; 108 const char *name; 109 const char *vers; 110 111 /* Name can't be shorter than "libx.so.0" */ 112 if ((len = strlen(dp->d_name)) < 9 || 113 strncmp(dp->d_name, "lib", 3) != 0) 114 continue; 115 name = dp->d_name + 3; 116 vers = dp->d_name + len; 117 while (vers > dp->d_name && isdigit(*(vers-1))) 118 vers--; 119 if (vers == dp->d_name + len) 120 continue; 121 if (vers < dp->d_name + 4 || 122 strncmp(vers - 4, ".so.", 4) != 0) 123 continue; 124 125 /* We have a valid shared library name. */ 126 namelen = (vers - 4) - name; 127 printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs, 128 namelen, name, vers, dirs[i], dp->d_name); 129 nlibs++; 130 } 131 closedir(dirp); 132 } 133} 134 135static void 136read_dirs_from_file(const char *hintsfile, const char *listfile) 137{ 138 FILE *fp; 139 char buf[MAXPATHLEN]; 140 int linenum; 141 142 if ((fp = fopen(listfile, "r")) == NULL) 143 err(1, "%s", listfile); 144 145 linenum = 0; 146 while (fgets(buf, sizeof buf, fp) != NULL) { 147 char *cp, *sp; 148 149 linenum++; 150 cp = buf; 151 /* Skip leading white space. */ 152 while (isspace(*cp)) 153 cp++; 154 if (*cp == '#' || *cp == '\0') 155 continue; 156 sp = cp; 157 /* Advance over the directory name. */ 158 while (!isspace(*cp) && *cp != '\0') 159 cp++; 160 /* Terminate the string and skip trailing white space. */ 161 if (*cp != '\0') { 162 *cp++ = '\0'; 163 while (isspace(*cp)) 164 cp++; 165 } 166 /* Now we had better be at the end of the line. */ 167 if (*cp != '\0') 168 warnx("%s:%d: trailing characters ignored", 169 listfile, linenum); 170 171 if ((sp = strdup(sp)) == NULL) 172 errx(1, "Out of memory"); 173 add_dir(hintsfile, sp); 174 } 175 176 fclose(fp); 177} 178 179static void 180read_elf_hints(const char *hintsfile, int must_exist) 181{ 182 int fd; 183 struct stat s; 184 void *mapbase; 185 struct elfhints_hdr *hdr; 186 char *strtab; 187 char *dirlist; 188 char *p; 189 190 if ((fd = open(hintsfile, O_RDONLY)) == -1) { 191 if (errno == ENOENT && !must_exist) 192 return; 193 err(1, "Cannot open \"%s\"", hintsfile); 194 } 195 if (fstat(fd, &s) == -1) 196 err(1, "Cannot stat \"%s\"", hintsfile); 197 if (s.st_size > MAXFILESIZE) 198 errx(1, "\"%s\" is unreasonably large", hintsfile); 199 /* 200 * We use a read-write, private mapping so that we can null-terminate 201 * some strings in it without affecting the underlying file. 202 */ 203 mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE, 204 MAP_PRIVATE, fd, 0); 205 if (mapbase == MAP_FAILED) 206 err(1, "Cannot mmap \"%s\"", hintsfile); 207 close(fd); 208 209 hdr = (struct elfhints_hdr *)mapbase; 210 if (hdr->magic != ELFHINTS_MAGIC) 211 errx(1, "\"%s\": invalid file format", hintsfile); 212 if (hdr->version != 1) 213 errx(1, "\"%s\": unrecognized file version (%d)", hintsfile, 214 hdr->version); 215 216 strtab = (char *)mapbase + hdr->strtab; 217 dirlist = strtab + hdr->dirlist; 218 219 if (*dirlist != '\0') 220 while ((p = strsep(&dirlist, ":")) != NULL) 221 add_dir(hintsfile, p); 222} 223 224void 225update_elf_hints(const char *hintsfile, int argc, char **argv, int merge) 226{ 227 int i; 228 229 if (merge) 230 read_elf_hints(hintsfile, 0); 231 for (i = 0; i < argc; i++) { 232 struct stat s; 233 234 if (stat(argv[i], &s) == -1) 235 warn("warning: %s", argv[i]); 236 else if (S_ISREG(s.st_mode)) 237 read_dirs_from_file(hintsfile, argv[i]); 238 else 239 add_dir(hintsfile, argv[i]); 240 } 241 write_elf_hints(hintsfile); 242} 243 244static void 245write_elf_hints(const char *hintsfile) 246{ 247 struct elfhints_hdr hdr; 248 char *tempname; 249 int fd; 250 FILE *fp; 251 int i; 252 253 if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1) 254 errx(1, "Out of memory"); 255 if ((fd = mkstemp(tempname)) == -1) 256 err(1, "mkstemp(%s)", tempname); 257 if (fchmod(fd, 0444) == -1) 258 err(1, "fchmod(%s)", tempname); 259 if ((fp = fdopen(fd, "wb")) == NULL) 260 err(1, "fdopen(%s)", tempname); 261 262 hdr.magic = ELFHINTS_MAGIC; 263 hdr.version = 1; 264 hdr.strtab = sizeof hdr; 265 hdr.strsize = 0; 266 hdr.dirlist = 0; 267 memset(hdr.spare, 0, sizeof hdr.spare); 268 269 /* Count up the size of the string table. */ 270 if (ndirs > 0) { 271 hdr.strsize += strlen(dirs[0]); 272 for (i = 1; i < ndirs; i++) 273 hdr.strsize += 1 + strlen(dirs[i]); 274 } 275 hdr.dirlistlen = hdr.strsize; 276 hdr.strsize++; /* For the null terminator */ 277 278 /* Write the header. */ 279 if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr) 280 err(1, "%s: write error", tempname); 281 /* Write the strings. */ 282 if (ndirs > 0) { 283 if (fputs(dirs[0], fp) == EOF) 284 err(1, "%s: write error", tempname); 285 for (i = 1; i < ndirs; i++) 286 if (fprintf(fp, ":%s", dirs[i]) < 0) 287 err(1, "%s: write error", tempname); 288 } 289 if (putc('\0', fp) == EOF || fclose(fp) == EOF) 290 err(1, "%s: write error", tempname); 291 292 if (rename(tempname, hintsfile) == -1) 293 err(1, "rename %s to %s", tempname, hintsfile); 294 free(tempname); 295} 296