sbin/ldconfig/elfhints.c

   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  * $FreeBSD$
  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-hints.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
  49 static void     add_dir(const char *, const char *, int);
  50 static void     read_dirs_from_file(const char *, const char *);
  51 static void     read_elf_hints(const char *, int);
  52 static void     write_elf_hints(const char *);
  53
  54 static const char       *dirs[MAXDIRS];
  55 static int               ndirs;
  56 int                      insecure;
  57
  58 static void
  59 add_dir(const char *hintsfile, const char *name, int trusted)
  60 {
  61         struct stat     stbuf;
  62         int             i;
  63
  64         /* Do some security checks */
  65         if (!trusted && !insecure) {
  66                 if (stat(name, &stbuf) == -1) {
  67                         warn("%s", name);
  68                         return;
  69                 }
  70                 if (stbuf.st_uid != 0) {
  71                         warnx("%s: ignoring directory not owned by root", name);
  72                         return;
  73                 }
  74                 if ((stbuf.st_mode & S_IWOTH) != 0) {
  75                         warnx("%s: ignoring world-writable directory", name);
  76                         return;
  77                 }
  78                 if ((stbuf.st_mode & S_IWGRP) != 0) {
  79                         warnx("%s: ignoring group-writable directory", name);
  80                         return;
  81                 }
  82         }
  83
  84         for (i = 0;  i < ndirs;  i++)
  85                 if (strcmp(dirs[i], name) == 0)
  86                         return;
  87         if (ndirs >= MAXDIRS)
  88                 errx(1, "\"%s\": Too many directories in path", hintsfile);
  89         dirs[ndirs++] = name;
  90 }
  91
  92 void
  93 list_elf_hints(const char *hintsfile)
  94 {
  95         int     i;
  96         int     nlibs;
  97
  98         read_elf_hints(hintsfile, 1);
  99         printf("%s:\n", hintsfile);
 100         printf("\tsearch directories:");
 101         for (i = 0;  i < ndirs;  i++)
 102                 printf("%c%s", i == 0 ? ' ' : ':', dirs[i]);
 103         printf("\n");
 104
 105         nlibs = 0;
 106         for (i = 0;  i < ndirs;  i++) {
 107                 DIR             *dirp;
 108                 struct dirent   *dp;
 109
 110                 if ((dirp = opendir(dirs[i])) == NULL)
 111                         continue;
 112                 while ((dp = readdir(dirp)) != NULL) {
 113                         int              len;
 114                         int              namelen;
 115                         const char      *name;
 116                         const char      *vers;
 117
 118                         /* Name can't be shorter than "libx.so.0" */
 119                         if ((len = strlen(dp->d_name)) < 9 ||
 120                             strncmp(dp->d_name, "lib", 3) != 0)
 121                                 continue;
 122                         name = dp->d_name + 3;
 123                         vers = dp->d_name + len;
 124                         while (vers > dp->d_name && isdigit(*(vers-1)))
 125                                 vers--;
 126                         if (vers == dp->d_name + len)
 127                                 continue;
 128                         if (vers < dp->d_name + 4 ||
 129                             strncmp(vers - 4, ".so.", 4) != 0)
 130                                 continue;
 131
 132                         /* We have a valid shared library name. */
 133                         namelen = (vers - 4) - name;
 134                         printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs,
 135                             namelen, name, vers, dirs[i], dp->d_name);
 136                         nlibs++;
 137                 }
 138                 closedir(dirp);
 139         }
 140 }
 141
 142 static void
 143 read_dirs_from_file(const char *hintsfile, const char *listfile)
 144 {
 145         FILE    *fp;
 146         char     buf[MAXPATHLEN];
 147         int      linenum;
 148
 149         if ((fp = fopen(listfile, "r")) == NULL)
 150                 err(1, "%s", listfile);
 151
 152         linenum = 0;
 153         while (fgets(buf, sizeof buf, fp) != NULL) {
 154                 char    *cp, *sp;
 155
 156                 linenum++;
 157                 cp = buf;
 158                 /* Skip leading white space. */
 159                 while (isspace(*cp))
 160                         cp++;
 161                 if (*cp == '#' || *cp == '\0')
 162                         continue;
 163                 sp = cp;
 164                 /* Advance over the directory name. */
 165                 while (!isspace(*cp) && *cp != '\0')
 166                         cp++;
 167                 /* Terminate the string and skip trailing white space. */
 168                 if (*cp != '\0') {
 169                         *cp++ = '\0';
 170                         while (isspace(*cp))
 171                                 cp++;
 172                 }
 173                 /* Now we had better be at the end of the line. */
 174                 if (*cp != '\0')
 175                         warnx("%s:%d: trailing characters ignored",
 176                             listfile, linenum);
 177
 178                 if ((sp = strdup(sp)) == NULL)
 179                         errx(1, "Out of memory");
 180                 add_dir(hintsfile, sp, 0);
 181         }
 182
 183         fclose(fp);
 184 }
 185
 186 static void
 187 read_elf_hints(const char *hintsfile, int must_exist)
 188 {
 189         int                      fd;
 190         struct stat              s;
 191         void                    *mapbase;
 192         struct elfhints_hdr     *hdr;
 193         char                    *strtab;
 194         char                    *dirlist;
 195         char                    *p;
 196
 197         if ((fd = open(hintsfile, O_RDONLY)) == -1) {
 198                 if (errno == ENOENT && !must_exist)
 199                         return;
 200                 err(1, "Cannot open \"%s\"", hintsfile);
 201         }
 202         if (fstat(fd, &s) == -1)
 203                 err(1, "Cannot stat \"%s\"", hintsfile);
 204         if (s.st_size > MAXFILESIZE)
 205                 errx(1, "\"%s\" is unreasonably large", hintsfile);
 206         /*
 207          * We use a read-write, private mapping so that we can null-terminate
 208          * some strings in it without affecting the underlying file.
 209          */
 210         mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE,
 211             MAP_PRIVATE, fd, 0);
 212         if (mapbase == MAP_FAILED)
 213                 err(1, "Cannot mmap \"%s\"", hintsfile);
 214         close(fd);
 215
 216         hdr = (struct elfhints_hdr *)mapbase;
 217         if (hdr->magic != ELFHINTS_MAGIC)
 218                 errx(1, "\"%s\": invalid file format", hintsfile);
 219         if (hdr->version != 1)
 220                 errx(1, "\"%s\": unrecognized file version (%d)", hintsfile,
 221                     hdr->version);
 222
 223         strtab = (char *)mapbase + hdr->strtab;
 224         dirlist = strtab + hdr->dirlist;
 225
 226         if (*dirlist != '\0')
 227                 while ((p = strsep(&dirlist, ":")) != NULL)
 228                         add_dir(hintsfile, p, 1);
 229 }
 230
 231 void
 232 update_elf_hints(const char *hintsfile, int argc, char **argv, int merge)
 233 {
 234         int     i;
 235
 236         if (merge)
 237                 read_elf_hints(hintsfile, 0);
 238         for (i = 0;  i < argc;  i++) {
 239                 struct stat     s;
 240
 241                 if (stat(argv[i], &s) == -1)
 242                         warn("warning: %s", argv[i]);
 243                 else if (S_ISREG(s.st_mode))
 244                         read_dirs_from_file(hintsfile, argv[i]);
 245                 else
 246                         add_dir(hintsfile, argv[i], 0);
 247         }
 248         write_elf_hints(hintsfile);
 249 }
 250
 251 static void
 252 write_elf_hints(const char *hintsfile)
 253 {
 254         struct elfhints_hdr      hdr;
 255         char                    *tempname;
 256         int                      fd;
 257         FILE                    *fp;
 258         int                      i;
 259
 260         if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1)
 261                 errx(1, "Out of memory");
 262         if ((fd = mkstemp(tempname)) ==  -1)
 263                 err(1, "mkstemp(%s)", tempname);
 264         if (fchmod(fd, 0444) == -1)
 265                 err(1, "fchmod(%s)", tempname);
 266         if ((fp = fdopen(fd, "wb")) == NULL)
 267                 err(1, "fdopen(%s)", tempname);
 268
 269         hdr.magic = ELFHINTS_MAGIC;
 270         hdr.version = 1;
 271         hdr.strtab = sizeof hdr;
 272         hdr.strsize = 0;
 273         hdr.dirlist = 0;
 274         memset(hdr.spare, 0, sizeof hdr.spare);
 275
 276         /* Count up the size of the string table. */
 277         if (ndirs > 0) {
 278                 hdr.strsize += strlen(dirs[0]);
 279                 for (i = 1;  i < ndirs;  i++)
 280                         hdr.strsize += 1 + strlen(dirs[i]);
 281         }
 282         hdr.dirlistlen = hdr.strsize;
 283         hdr.strsize++;  /* For the null terminator */
 284
 285         /* Write the header. */
 286         if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr)
 287                 err(1, "%s: write error", tempname);
 288         /* Write the strings. */
 289         if (ndirs > 0) {
 290                 if (fputs(dirs[0], fp) == EOF)
 291                         err(1, "%s: write error", tempname);
 292                 for (i = 1;  i < ndirs;  i++)
 293                         if (fprintf(fp, ":%s", dirs[i]) < 0)
 294                                 err(1, "%s: write error", tempname);
 295         }
 296         if (putc('\0', fp) == EOF || fclose(fp) == EOF)
 297                 err(1, "%s: write error", tempname);
 298
 299         if (rename(tempname, hintsfile) == -1)
 300                 err(1, "rename %s to %s", tempname, hintsfile);
 301         free(tempname);
 302 }