1 /* ----------------------------------------------------------------------- *
3 * Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
4 * Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
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.
12 * ----------------------------------------------------------------------- */
15 * syslinux.c - Linux installer program for SYSLINUX
17 * This is Linux-specific by now.
19 * This is an alternate version of the installer which doesn't require
20 * mtools, but requires root privilege.
24 * If DO_DIRECT_MOUNT is 0, call mount(8)
25 * If DO_DIRECT_MOUNT is 1, call mount(2)
28 # define DO_DIRECT_MOUNT 1
30 # define DO_DIRECT_MOUNT 0 /* glibc has broken losetup ioctls */
34 #define _XOPEN_SOURCE 500 /* For pread() pwrite() */
35 #define _FILE_OFFSET_BITS 64
46 #include <sys/types.h>
48 #include <sys/mount.h>
50 #include "linuxioctl.h"
54 # define _PATH_MOUNT "/bin/mount"
57 # define _PATH_UMOUNT "/bin/umount"
60 # define _PATH_TMP "/tmp/"
66 # include <linux/loop.h>
73 #include "syslxopt.h" /* unified options */
75 extern const char *program; /* Name of program */
78 char *mntpath = NULL; /* Path on which to mount */
83 #define boot_image syslinux_ldlinux
84 #define boot_image_len syslinux_ldlinux_len
87 int loop_fd = -1; /* Loop device */
90 void __attribute__ ((noreturn)) die(const char *msg)
92 fprintf(stderr, "%s: %s\n", program, msg);
96 ioctl(loop_fd, LOOP_CLR_FD, 0); /* Free loop device */
111 int do_mount(int dev_fd, int *cookie, const char *mntpath, const char *fstype)
117 if (fstat(dev_fd, &st) < 0)
122 if (!S_ISBLK(st.st_mode)) {
123 /* It's file, need to mount it loopback */
125 struct loop_info64 loopinfo;
128 for (n = 0; loop_fd < 0; n++) {
129 snprintf(devfdname, sizeof devfdname, "/dev/loop%u", n);
130 loop_fd = open(devfdname, O_RDWR);
131 if (loop_fd < 0 && errno == ENOENT) {
132 die("no available loopback device!");
134 if (ioctl(loop_fd, LOOP_SET_FD, (void *)dev_fd)) {
138 die("cannot set up loopback device");
143 if (ioctl(loop_fd, LOOP_GET_STATUS64, &loopinfo) ||
144 (loopinfo.lo_offset = opt.offset,
145 ioctl(loop_fd, LOOP_SET_STATUS64, &loopinfo)))
146 die("cannot set up loopback device");
151 snprintf(devfdname, sizeof devfdname, "/proc/%lu/fd/%d",
152 (unsigned long)mypid, dev_fd);
156 return mount(devfdname, mntpath, fstype,
157 MS_NOEXEC | MS_NOSUID, "umask=077,quiet");
161 char devfdname[128], mnt_opts[128];
165 snprintf(devfdname, sizeof devfdname, "/proc/%lu/fd/%d",
166 (unsigned long)mypid, dev_fd);
172 if (!S_ISBLK(st.st_mode)) {
173 snprintf(mnt_opts, sizeof mnt_opts,
174 "rw,nodev,noexec,loop,offset=%llu,umask=077,quiet",
175 (unsigned long long)opt.offset);
177 snprintf(mnt_opts, sizeof mnt_opts,
178 "rw,nodev,noexec,umask=077,quiet");
180 execl(_PATH_MOUNT, _PATH_MOUNT, "-t", fstype, "-o", mnt_opts,
181 devfdname, mntpath, NULL);
182 _exit(255); /* execl failed */
185 w = waitpid(f, &status, 0);
186 return (w != f || status) ? -1 : 0;
194 void do_umount(const char *mntpath, int cookie)
197 int loop_fd = cookie;
199 if (umount2(mntpath, 0))
200 die("could not umount path");
203 ioctl(loop_fd, LOOP_CLR_FD, 0); /* Free loop device */
217 execl(_PATH_UMOUNT, _PATH_UMOUNT, mntpath, NULL);
220 w = waitpid(f, &status, 0);
221 if (w != f || status) {
228 * Make any user-specified ADV modifications
235 if (syslinux_setadv(ADV_BOOTONCE, strlen(opt.set_once), opt.set_once)) {
236 fprintf(stderr, "%s: not enough space for boot-once command\n",
246 * Modify the ADV of an existing installation
248 int modify_existing_adv(const char *path)
251 syslinux_reset_adv(syslinux_adv);
252 else if (read_adv(path, "ldlinux.sys") < 0)
255 if (modify_adv() < 0)
258 if (write_adv(path, "ldlinux.sys") < 0)
264 int main(int argc, char *argv[])
266 static unsigned char sectbuf[SECTOR_SIZE];
274 sector_t *sectors = NULL;
275 int ldlinux_sectors = (boot_image_len + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
283 parse_options(argc, argv, MODE_SYSLINUX);
285 /* Note: subdir is guaranteed to start and end in / */
286 if (opt.directory && opt.directory[0]) {
287 int len = strlen(opt.directory);
288 asprintf(&subdir, "%s%s%s",
289 opt.directory[0] == '/' ? "" : "/",
291 opt.directory[len-1] == '/' ? "" : "/");
301 usage(EX_USAGE, MODE_SYSLINUX);
304 * First make sure we can open the device at all, and that we have
305 * read/write permission.
307 dev_fd = open(opt.device, O_RDWR);
308 if (dev_fd < 0 || fstat(dev_fd, &st) < 0) {
313 if (!S_ISBLK(st.st_mode) && !S_ISREG(st.st_mode) && !S_ISCHR(st.st_mode)) {
314 die("not a device or regular file");
317 if (opt.offset && S_ISBLK(st.st_mode)) {
318 die("can't combine an offset with a block device");
322 xpread(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
326 * Check to see that what we got was indeed an MS-DOS boot sector/superblock
328 if ((errmsg = syslinux_check_bootsect(sectbuf))) {
329 fprintf(stderr, "%s: %s\n", opt.device, errmsg);
334 * Now mount the device.
337 die("This program needs root privilege");
343 /* We're root or at least setuid.
344 Make a temp dir and pass all the gunky options to mount. */
346 if (chdir(_PATH_TMP)) {
350 #define TMP_MODE (S_IXUSR|S_IWUSR|S_IXGRP|S_IWGRP|S_IWOTH|S_IXOTH|S_ISVTX)
352 if (stat(".", &dst) || !S_ISDIR(dst.st_mode) ||
353 (dst.st_mode & TMP_MODE) != TMP_MODE) {
354 die("possibly unsafe " _PATH_TMP " permissions");
358 snprintf(mntname, sizeof mntname, "syslinux.mnt.%lu.%d",
359 (unsigned long)mypid, i);
361 if (lstat(mntname, &dst) != -1 || errno != ENOENT)
364 rv = mkdir(mntname, 0000);
367 if (errno == EEXIST || errno == EINTR)
373 if (lstat(mntname, &dst) || dst.st_mode != (S_IFDIR | 0000) ||
375 die("someone is trying to symlink race us!");
377 break; /* OK, got something... */
383 if (do_mount(dev_fd, &mnt_cookie, mntpath, "vfat") &&
384 do_mount(dev_fd, &mnt_cookie, mntpath, "msdos")) {
389 ldlinux_path = alloca(strlen(mntpath) + strlen(subdir) + 1);
390 sprintf(ldlinux_path, "%s%s", mntpath, subdir);
392 ldlinux_name = alloca(strlen(ldlinux_path) + 14);
398 sprintf(ldlinux_name, "%sldlinux.sys", ldlinux_path);
400 /* update ADV only ? */
401 if (opt.update_only == -1) {
402 if (opt.reset_adv || opt.set_once) {
403 modify_existing_adv(ldlinux_path);
404 do_umount(mntpath, mnt_cookie);
409 fprintf(stderr, "%s: please specify --install or --update for the future\n", argv[0]);
414 /* Read a pre-existing ADV, if already installed */
416 syslinux_reset_adv(syslinux_adv);
417 else if (read_adv(ldlinux_path, "ldlinux.sys") < 0)
418 syslinux_reset_adv(syslinux_adv);
419 if (modify_adv() < 0)
422 if ((fd = open(ldlinux_name, O_RDONLY)) >= 0) {
423 uint32_t zero_attr = 0;
424 ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &zero_attr);
428 unlink(ldlinux_name);
429 fd = open(ldlinux_name, O_WRONLY | O_CREAT | O_TRUNC, 0444);
436 /* Write it the first time */
437 if (xpwrite(fd, boot_image, boot_image_len, 0) != (int)boot_image_len ||
438 xpwrite(fd, syslinux_adv, 2 * ADV_SIZE,
439 boot_image_len) != 2 * ADV_SIZE) {
440 fprintf(stderr, "%s: write failure on %s\n", program, ldlinux_name);
449 uint32_t attr = 0x07; /* Hidden+System+Readonly */
450 ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &attr);
454 * Create a block map.
456 ldlinux_sectors += 2; /* 2 ADV sectors */
457 sectors = calloc(ldlinux_sectors, sizeof *sectors);
458 if (sectmap(fd, sectors, ldlinux_sectors)) {
466 do_umount(mntpath, mnt_cookie);
474 * Patch ldlinux.sys and the boot sector
476 i = syslinux_patch(sectors, ldlinux_sectors, opt.stupid_mode,
477 opt.raid_mode, subdir, NULL);
478 patch_sectors = (i + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
481 * Write the now-patched first sectors of ldlinux.sys
483 for (i = 0; i < patch_sectors; i++) {
484 xpwrite(dev_fd, boot_image + i * SECTOR_SIZE, SECTOR_SIZE,
485 opt.offset + ((off_t) sectors[i] << SECTOR_SHIFT));
489 * To finish up, write the boot sector
492 /* Read the superblock again since it might have changed while mounted */
493 xpread(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);
495 /* Copy the syslinux code into the boot sector */
496 syslinux_make_bootsect(sectbuf);
498 /* Write new boot sector */
499 xpwrite(dev_fd, sectbuf, SECTOR_SIZE, opt.offset);