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 #include "syslxrw.h"
  46
  47 const char *program;
  48 pid_t mypid;
  49
  50 void __attribute__ ((noreturn)) die(const char *msg)
  51 {
  52     fprintf(stderr, "%s: %s\n", program, msg);
  53     exit(1);
  54 }
  55
  56 void __attribute__ ((noreturn)) die_err(const char *msg)
  57 {
  58     fprintf(stderr, "%s: %s: %s\n", program, msg, strerror(errno));
  59     exit(1);
  60 }
  61
  62 /*
  63  * Version of the read function suitable for libfat
  64  */
  65 int libfat_xpread(intptr_t pp, void *buf, size_t secsize,
  66                   libfat_sector_t sector)
  67 {
  68     off_t offset = (off_t) sector * secsize + opt.offset;
  69     return xpread(pp, buf, secsize, offset);
  70 }
  71
  72 static int move_file(char *filename)
  73 {
  74     char target_file[4096], command[5120];
  75     char *cp = target_file, *ep = target_file + sizeof target_file - 16;
  76     const char *sd;
  77     int slash = 1;
  78     int status;
  79
  80     cp += sprintf(cp, "'s:/");
  81     for (sd = opt.directory; *sd; sd++) {
  82         if (*sd == '/' || *sd == '\\') {
  83             if (slash)
  84                 continue;       /* Remove duplicated slashes */
  85             slash = 1;
  86         } else if (*sd == '\'' || *sd == '!') {
  87             slash = 0;
  88             if (cp < ep)
  89                 *cp++ = '\'';
  90             if (cp < ep)
  91                 *cp++ = '\\';
  92             if (cp < ep)
  93                 *cp++ = *sd;
  94             if (cp < ep)
  95                 *cp++ = '\'';
  96             continue;
  97         } else {
  98             slash = 0;
  99         }
 100
 101         if (cp < ep)
 102             *cp++ = *sd;
 103     }
 104     if (!slash)
 105         *cp++ = '/';
 106     sprintf(cp, "%s'", filename);
 107
 108     /* This command may fail legitimately */
 109     sprintf(command, "mattrib -h -r -s %s 2>/dev/null", target_file);
 110     status = system(command);
 111     (void)status;               /* Keep _FORTIFY_SOURCE happy */
 112
 113     sprintf(command, "mmove -D o -D O s:/%s %s", filename, target_file);
 114     status = system(command);
 115
 116     if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 117         fprintf(stderr,
 118                 "%s: warning: unable to move %s\n", program, filename);
 119
 120         sprintf(command, "mattrib +r +h +s s:/%s", filename);
 121         status = system(command);
 122     } else {
 123         sprintf(command, "mattrib +r +h +s %s", target_file);
 124         status = system(command);
 125     }
 126
 127     return status;
 128 }
 129
 130 int main(int argc, char *argv[])
 131 {
 132     static unsigned char sectbuf[SECTOR_SIZE];
 133     int dev_fd;
 134     struct stat st;
 135     int status;
 136     const char *tmpdir;
 137     char *mtools_conf;
 138     int mtc_fd;
 139     FILE *mtc, *mtp;
 140     struct libfat_filesystem *fs;
 141     libfat_sector_t s, *secp;
 142     libfat_sector_t *sectors;
 143     int32_t ldlinux_cluster;
 144     int nsectors;
 145     const char *errmsg;
 146     int ldlinux_sectors, patch_sectors;
 147     int i;
 148
 149     (void)argc;                 /* Unused */
 150
 151     mypid = getpid();
 152     program = argv[0];
 153
 154     parse_options(argc, argv, MODE_SYSLINUX);
 155
 156     if (!opt.device)
 157         usage(EX_USAGE, MODE_SYSLINUX);
 158
 159     if (opt.sectors || opt.heads || opt.reset_adv || opt.set_once
 160         || (opt.update_only > 0) || opt.menu_save) {
 161         fprintf(stderr,
 162                 "At least one specified option not yet implemented"
 163                 " for this installer.\n");
 164         exit(1);
 165     }
 166
 167     /*
 168      * Temp directory of choice...
 169      */
 170     tmpdir = getenv("TMPDIR");
 171     if (!tmpdir) {
 172 #ifdef P_tmpdir
 173         tmpdir = P_tmpdir;
 174 #elif defined(_PATH_TMP)
 175         tmpdir = _PATH_TMP;
 176 #else
 177         tmpdir = "/tmp";
 178 #endif
 179     }
 180
 181     /*
 182      * First make sure we can open the device at all, and that we have
 183      * read/write permission.
 184      */
 185     dev_fd = open(opt.device, O_RDWR);
 186     if (dev_fd < 0 || fstat(dev_fd, &st) < 0) {
 187         die_err(opt.device);
 188         exit(1);
 189     }
 190
 191     if (!opt.force && !S_ISBLK(st.st_mode) && !S_ISREG(st.st_mode)) {
 192         fprintf(stderr,
 193                 "%s: not a block device or regular file (use -f to override)\n",
 194                 opt.device);
 195         exit(1);
 196     }
 197
 198     xpread(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
 199
 200     /*
 201      * Check to see that what we got was indeed an MS-DOS boot sector/superblock
 202      */
 203     if ((errmsg = syslinux_check_bootsect(sectbuf, NULL))) {
 204         die(errmsg);
 205     }
 206
 207     /*
 208      * Create an mtools configuration file
 209      */
 210     if (asprintf(&mtools_conf, "%s//syslinux-mtools-XXXXXX", tmpdir) < 0 ||
 211         !mtools_conf)
 212         die_err(tmpdir);
 213
 214     mtc_fd = mkstemp(mtools_conf);
 215     if (mtc_fd < 0 || !(mtc = fdopen(mtc_fd, "w")))
 216         die_err(mtools_conf);
 217
 218     fprintf(mtc,
 219             /* These are needed for some flash memories */
 220             "MTOOLS_SKIP_CHECK=1\n"
 221             "MTOOLS_FAT_COMPATIBILITY=1\n"
 222             "drive s:\n"
 223             "  file=\"/proc/%lu/fd/%d\"\n"
 224             "  offset=%llu\n",
 225             (unsigned long)mypid,
 226             dev_fd, (unsigned long long)opt.offset);
 227
 228     if (ferror(mtc) || fclose(mtc))
 229         die_err(mtools_conf);
 230
 231     /*
 232      * Run mtools to create the LDLINUX.SYS file
 233      */
 234     if (setenv("MTOOLSRC", mtools_conf, 1)) {
 235         perror(program);
 236         exit(1);
 237     }
 238
 239     /*
 240      * Create a vacuous ADV in memory.  This should be smarter.
 241      */
 242     syslinux_reset_adv(syslinux_adv);
 243
 244     /* This command may fail legitimately */
 245     status = system("mattrib -h -r -s s:/ldlinux.sys 2>/dev/null");
 246     (void)status;               /* Keep _FORTIFY_SOURCE happy */
 247
 248     mtp = popen("mcopy -D o -D O -o - s:/ldlinux.sys", "w");
 249     if (!mtp ||
 250         fwrite((const void _force *)syslinux_ldlinux,
 251                1, syslinux_ldlinux_len, mtp)
 252                 != syslinux_ldlinux_len ||
 253         fwrite((const void _force *)syslinux_adv,
 254                1, 2 * ADV_SIZE, mtp)
 255                 != 2 * ADV_SIZE ||
 256         (status = pclose(mtp), !WIFEXITED(status) || WEXITSTATUS(status))) {
 257         die("failed to create ldlinux.sys");
 258     }
 259
 260     /*
 261      * Now, use libfat to create a block map
 262      */
 263     ldlinux_sectors = (syslinux_ldlinux_len + 2 * ADV_SIZE
 264                        + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
 265     sectors = calloc(ldlinux_sectors, sizeof *sectors);
 266     fs = libfat_open(libfat_xpread, dev_fd);
 267     ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
 268     secp = sectors;
 269     nsectors = 0;
 270     s = libfat_clustertosector(fs, ldlinux_cluster);
 271     while (s && nsectors < ldlinux_sectors) {
 272         *secp++ = s;
 273         nsectors++;
 274         s = libfat_nextsector(fs, s);
 275     }
 276     libfat_close(fs);
 277
 278     /* Patch ldlinux.sys and the boot sector */
 279     i = syslinux_patch(sectors, nsectors, opt.stupid_mode, opt.raid_mode,
 280                        opt.directory, NULL);
 281     patch_sectors = (i + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
 282
 283     /* Write the now-patched first sectors of ldlinux.sys */
 284     for (i = 0; i < patch_sectors; i++) {
 285         xpwrite(dev_fd, (const char _force *)syslinux_ldlinux
 286                 + i * SECTOR_SIZE, SECTOR_SIZE,
 287                 opt.offset + ((off_t) sectors[i] << SECTOR_SHIFT));
 288     }
 289
 290     /* Move ldlinux.sys to the desired location */
 291     if (opt.directory) {
 292         status = move_file("ldlinux.sys");
 293     } else {
 294         status = system("mattrib +r +h +s s:/ldlinux.sys");
 295     }
 296
 297     if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 298         fprintf(stderr,
 299                 "%s: warning: failed to set system bit on ldlinux.sys\n",
 300                 program);
 301     }
 302
 303     /* This command may fail legitimately */
 304     status = system("mattrib -h -r -s s:/ldlinux.c32 2>/dev/null");
 305     (void)status;               /* Keep _FORTIFY_SOURCE happy */
 306
 307     mtp = popen("mcopy -D o -D O -o - s:/ldlinux.c32", "w");
 308     if (!mtp || fwrite((const char _force *)syslinux_ldlinuxc32,
 309                        1, syslinux_ldlinuxc32_len, mtp)
 310         != syslinux_ldlinuxc32_len ||
 311         (status = pclose(mtp), !WIFEXITED(status) || WEXITSTATUS(status))) {
 312         die("failed to create ldlinux.c32");
 313     }
 314
 315     /* Move ldlinux.c32 to the desired location */
 316     if (opt.directory) {
 317         status = move_file("ldlinux.c32");
 318     } else {
 319         status = system("mattrib +r +h +s s:/ldlinux.c32");
 320     }
 321
 322     if (!WIFEXITED(status) || WEXITSTATUS(status)) {
 323         fprintf(stderr,
 324                 "%s: warning: failed to set system bit on ldlinux.c32\n",
 325                 program);
 326     }
 327
 328     /*
 329      * Cleanup
 330      */
 331     unlink(mtools_conf);
 332
 333     /*
 334      * To finish up, write the boot sector
 335      */
 336
 337     /* Read the superblock again since it might have changed while mounted */
 338     xpread(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
 339
 340     /* Copy the syslinux code into the boot sector */
 341     syslinux_make_bootsect(sectbuf, VFAT);
 342
 343     /* Write new boot sector */
 344     xpwrite(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
 345
 346     close(dev_fd);
 347     sync();
 348
 349     /* Done! */
 350
 351     return 0;
 352 }