mtools/syslinux.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
   4  *   Copyright 2010 Intel Corporation; author: H. Peter Anvin
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   9  *   Boston MA 02111-1307, USA; either version 2 of the License, or
  10  *   (at your option) any later version; incorporated herein by reference.
  11  *
  12  * ----------------------------------------------------------------------- */
  13
  14 /*
  15  * syslinux.c - Linux installer program for SYSLINUX
  16  *
  17  * This program now requires mtools.  It turned out to be a lot
  18  * easier to deal with than dealing with needing mount privileges.
  19  * We need device write permission anyway.
  20  */
  21
  22 #define _GNU_SOURCE
  23 #include <alloca.h>
  24 #include <errno.h>
  25 #include <fcntl.h>
  26 #include <getopt.h>
  27 #include <inttypes.h>
  28 #include <mntent.h>
  29 #include <paths.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33 #include <sysexits.h>
  34 #include <syslog.h>
  35 #include <unistd.h>
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <sys/wait.h>
  39
  40 #include "syslinux.h"
  41 #include "libfat.h"
  42 #include "setadv.h"
  43 #include "syslxopt.h"
  44 #include "syslxfs.h"
  45
  46 char *program;                  /* Name of program */
  47 pid_t mypid;
  48
  49 void __attribute__ ((noreturn)) die(const char *msg)
  50 {
  51     fprintf(stderr, "%s: %s\n", program, msg);
  52     exit(1);
  53 }
  54
  55 void __attribute__ ((noreturn)) die_err(const char *msg)
  56 {
  57     fprintf(stderr, "%s: %s: %s\n", program, msg, strerror(errno));
  58     exit(1);
  59 }
  60
  61 /*
  62  * read/write wrapper functions
  63  */
  64 ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
  65 {
  66     char *bufp = (char *)buf;
  67     ssize_t rv;
  68     ssize_t done = 0;
  69
  70     while (count) {
  71         rv = pread(fd, bufp, count, offset);
  72         if (rv == 0) {
  73             die("short read");
  74         } else if (rv == -1) {
  75             if (errno == EINTR) {
  76                 continue;
  77             } else {
  78                 die(strerror(errno));
  79             }
  80         } else {
  81             bufp += rv;
  82             offset += rv;
  83             done += rv;
  84             count -= rv;
  85         }
  86     }
  87
  88     return done;
  89 }
  90
  91 ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
  92 {
  93     const char *bufp = (const char *)buf;
  94     ssize_t rv;
  95     ssize_t done = 0;
  96
  97     while (count) {
  98         rv = pwrite(fd, bufp, count, offset);
  99         if (rv == 0) {
 100             die("short write");
 101         } else if (rv == -1) {
 102             if (errno == EINTR) {
 103                 continue;
 104             } else {
 105                 die(strerror(errno));
 106             }
 107         } else {
 108             bufp += rv;
 109             offset += rv;
 110             done += rv;
 111             count -= rv;
 112         }
 113     }
 114
 115     return done;
 116 }
 117
 118 /*
 119  * Version of the read function suitable for libfat
 120  */
 121 int libfat_xpread(intptr_t pp, void *buf, size_t secsize,
 122                   libfat_sector_t sector)
 123 {
 124     off_t offset = (off_t) sector * secsize + opt.offset;
 125     return xpread(pp, buf, secsize, offset);
 126 }
 127
 128 static int move_file(char *filename)
 129 {
 130     char target_file[4096], command[5120];
 131     char *cp = target_file, *ep = target_file + sizeof target_file - 16;
 132     const char *sd;
 133     int slash = 1;
 134     int status;
 135
 136     cp += sprintf(cp, "'s:/");
 137     for (sd = opt.directory; *sd; sd++) {
 138         if (*sd == '/' || *sd == '\\') {
 139             if (slash)
 140                 continue;       /* Remove duplicated slashes */
 141             slash = 1;
 142         } else if (*sd == '\'' || *sd == '!') {
 143             slash = 0;
 144             if (cp < ep)
 145                 *cp++ = '\'';
 146             if (cp < ep)
 147                 *cp++ = '\\';
 148             if (cp < ep)
 149                 *cp++ = *sd;
 150             if (cp < ep)
 151                 *cp++ = '\'';
 152             continue;
 153         } else {
 154             slash = 0;
 155         }
 156
 157         if (cp < ep)
 158             *cp++ = *sd;
 159     }
 160     if (!slash)
 161         *cp++ = '/';
 162     sprintf(cp, "%s'", filename);
 163
 164     /* This command may fail legitimately */
 165     sprintf(command, "mattrib -h -r -s %s 2>/dev/null", target_file);
 166     status = system(command);
 167     (void)status;               /* Keep _FORTIFY_SOURCE happy */
 168
 169     sprintf(command, "mmove -D o -D O s:/%s %s", filename, target_file);
 170     status = system(command);
 171
 172     if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 173         fprintf(stderr,
 174                 "%s: warning: unable to move %s\n", program, filename);
 175
 176         sprintf(command, "mattrib +r +h +s s:/%s", filename);
 177         status = system(command);
 178     } else {
 179         sprintf(command, "mattrib +r +h +s %s", target_file);
 180         status = system(command);
 181     }
 182
 183     return status;
 184 }
 185
 186 int main(int argc, char *argv[])
 187 {
 188     static unsigned char sectbuf[SECTOR_SIZE];
 189     int dev_fd;
 190     struct stat st;
 191     int status;
 192     const char *tmpdir;
 193     char *mtools_conf;
 194     int mtc_fd;
 195     FILE *mtc, *mtp;
 196     struct libfat_filesystem *fs;
 197     libfat_sector_t s, *secp;
 198     libfat_sector_t *sectors;
 199     int32_t ldlinux_cluster;
 200     int nsectors;
 201     const char *errmsg;
 202     int ldlinux_sectors, patch_sectors;
 203     int i;
 204
 205     (void)argc;                 /* Unused */
 206
 207     mypid = getpid();
 208     program = argv[0];
 209
 210     parse_options(argc, argv, MODE_SYSLINUX);
 211
 212     if (!opt.device)
 213         usage(EX_USAGE, MODE_SYSLINUX);
 214
 215     if (opt.sectors || opt.heads || opt.reset_adv || opt.set_once
 216         || (opt.update_only > 0) || opt.menu_save) {
 217         fprintf(stderr,
 218                 "At least one specified option not yet implemented"
 219                 " for this installer.\n");
 220         exit(1);
 221     }
 222
 223     /*
 224      * Temp directory of choice...
 225      */
 226     tmpdir = getenv("TMPDIR");
 227     if (!tmpdir) {
 228 #ifdef P_tmpdir
 229         tmpdir = P_tmpdir;
 230 #elif defined(_PATH_TMP)
 231         tmpdir = _PATH_TMP;
 232 #else
 233         tmpdir = "/tmp";
 234 #endif
 235     }
 236
 237     /*
 238      * First make sure we can open the device at all, and that we have
 239      * read/write permission.
 240      */
 241     dev_fd = open(opt.device, O_RDWR);
 242     if (dev_fd < 0 || fstat(dev_fd, &st) < 0) {
 243         die_err(opt.device);
 244         exit(1);
 245     }
 246
 247     if (!opt.force && !S_ISBLK(st.st_mode) && !S_ISREG(st.st_mode)) {
 248         fprintf(stderr,
 249                 "%s: not a block device or regular file (use -f to override)\n",
 250                 opt.device);
 251         exit(1);
 252     }
 253
 254     xpread(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
 255
 256     /*
 257      * Check to see that what we got was indeed an MS-DOS boot sector/superblock
 258      */
 259     if ((errmsg = syslinux_check_bootsect(sectbuf, NULL))) {
 260         die(errmsg);
 261     }
 262
 263     /*
 264      * Create an mtools configuration file
 265      */
 266     if (asprintf(&mtools_conf, "%s//syslinux-mtools-XXXXXX", tmpdir) < 0 ||
 267         !mtools_conf)
 268         die_err(tmpdir);
 269
 270     mtc_fd = mkstemp(mtools_conf);
 271     if (mtc_fd < 0 || !(mtc = fdopen(mtc_fd, "w")))
 272         die_err(mtools_conf);
 273
 274     fprintf(mtc,
 275             /* These are needed for some flash memories */
 276             "MTOOLS_SKIP_CHECK=1\n"
 277             "MTOOLS_FAT_COMPATIBILITY=1\n"
 278             "drive s:\n"
 279             "  file=\"/proc/%lu/fd/%d\"\n"
 280             "  offset=%llu\n",
 281             (unsigned long)mypid,
 282             dev_fd, (unsigned long long)opt.offset);
 283
 284     if (ferror(mtc) || fclose(mtc))
 285         die_err(mtools_conf);
 286
 287     /*
 288      * Run mtools to create the LDLINUX.SYS file
 289      */
 290     if (setenv("MTOOLSRC", mtools_conf, 1)) {
 291         perror(program);
 292         exit(1);
 293     }
 294
 295     /*
 296      * Create a vacuous ADV in memory.  This should be smarter.
 297      */
 298     syslinux_reset_adv(syslinux_adv);
 299
 300     /* This command may fail legitimately */
 301     status = system("mattrib -h -r -s s:/ldlinux.sys 2>/dev/null");
 302     (void)status;               /* Keep _FORTIFY_SOURCE happy */
 303
 304     mtp = popen("mcopy -D o -D O -o - s:/ldlinux.sys", "w");
 305     if (!mtp ||
 306         fwrite((const void _force *)syslinux_ldlinux,
 307                1, syslinux_ldlinux_len, mtp)
 308                 != syslinux_ldlinux_len ||
 309         fwrite((const void _force *)syslinux_adv,
 310                1, 2 * ADV_SIZE, mtp)
 311                 != 2 * ADV_SIZE ||
 312         (status = pclose(mtp), !WIFEXITED(status) || WEXITSTATUS(status))) {
 313         die("failed to create ldlinux.sys");
 314     }
 315
 316     /*
 317      * Now, use libfat to create a block map
 318      */
 319     ldlinux_sectors = (syslinux_ldlinux_len + 2 * ADV_SIZE
 320                        + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
 321     sectors = calloc(ldlinux_sectors, sizeof *sectors);
 322     fs = libfat_open(libfat_xpread, dev_fd);
 323     ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
 324     secp = sectors;
 325     nsectors = 0;
 326     s = libfat_clustertosector(fs, ldlinux_cluster);
 327     while (s && nsectors < ldlinux_sectors) {
 328         *secp++ = s;
 329         nsectors++;
 330         s = libfat_nextsector(fs, s);
 331     }
 332     libfat_close(fs);
 333
 334     /* Patch ldlinux.sys and the boot sector */
 335     i = syslinux_patch(sectors, nsectors, opt.stupid_mode, opt.raid_mode,
 336                        opt.directory, NULL);
 337     patch_sectors = (i + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
 338
 339     /* Write the now-patched first sectors of ldlinux.sys */
 340     for (i = 0; i < patch_sectors; i++) {
 341         xpwrite(dev_fd, (const char _force *)syslinux_ldlinux
 342                 + i * SECTOR_SIZE, SECTOR_SIZE,
 343                 opt.offset + ((off_t) sectors[i] << SECTOR_SHIFT));
 344     }
 345
 346     /* Move ldlinux.sys to the desired location */
 347     if (opt.directory) {
 348         status = move_file("ldlinux.sys");
 349     } else {
 350         status = system("mattrib +r +h +s s:/ldlinux.sys");
 351     }
 352
 353     if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 354         fprintf(stderr,
 355                 "%s: warning: failed to set system bit on ldlinux.sys\n",
 356                 program);
 357     }
 358
 359     /* This command may fail legitimately */
 360     status = system("mattrib -h -r -s s:/ldlinux.c32 2>/dev/null");
 361     (void)status;               /* Keep _FORTIFY_SOURCE happy */
 362
 363     mtp = popen("mcopy -D o -D O -o - s:/ldlinux.c32", "w");
 364     if (!mtp || fwrite((const char _force *)syslinux_ldlinuxc32,
 365                        1, syslinux_ldlinuxc32_len, mtp)
 366         != syslinux_ldlinuxc32_len ||
 367         (status = pclose(mtp), !WIFEXITED(status) || WEXITSTATUS(status))) {
 368         die("failed to create ldlinux.c32");
 369     }
 370
 371     /* Move ldlinux.c32 to the desired location */
 372     if (opt.directory) {
 373         status = move_file("ldlinux.c32");
 374     } else {
 375         status = system("mattrib +r +h +s s:/ldlinux.c32");
 376     }
 377
 378     if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 379         fprintf(stderr,
 380                 "%s: warning: failed to set system bit on ldlinux.c32\n",
 381                 program);
 382     }
 383
 384     /*
 385      * Cleanup
 386      */
 387     unlink(mtools_conf);
 388
 389     /*
 390      * To finish up, write the boot sector
 391      */
 392
 393     /* Read the superblock again since it might have changed while mounted */
 394     xpread(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
 395
 396     /* Copy the syslinux code into the boot sector */
 397     syslinux_make_bootsect(sectbuf, VFAT);
 398
 399     /* Write new boot sector */
 400     xpwrite(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
 401
 402     close(dev_fd);
 403     sync();
 404
 405     /* Done! */
 406
 407     return 0;
 408 }