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/* $OpenBSD: disk.c,v 1.3 2020/08/29 11:46:54 kettenis Exp $ */
/*
* Copyright (c) 2019 Visa Hankala
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/disklabel.h>
#include <sys/dkio.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
#include "cmd.h"
int disk_proberoot(const char *);
int mounted = 0;
int rdroot = -1; /* fd that points to the root of the ramdisk */
const u_char zeroduid[8];
void
disk_init(void)
{
char rootdevs[1024];
char bootduid[17];
char *devname, *disknames, *ptr;
size_t size;
int mib[2];
rdroot = open("/", O_RDONLY);
if (rdroot == -1)
err(1, "failed to open root directory fd");
if (strlen(cmd.bootdev) != 0)
return;
mib[0] = CTL_HW;
mib[1] = HW_DISKNAMES;
size = 0;
if (sysctl(mib, 2, NULL, &size, NULL, 0) == -1) {
fprintf(stderr, "%s: cannot get hw.disknames: %s\n", __func__,
strerror(errno));
return;
}
disknames = malloc(size);
if (disknames == NULL) {
fprintf(stderr, "%s: out of memory\n", __func__);
return;
}
if (sysctl(mib, 2, disknames, &size, NULL, 0) == -1) {
fprintf(stderr, "%s: cannot get hw.disknames: %s\n", __func__,
strerror(errno));
free(disknames);
return;
}
snprintf(bootduid, sizeof(bootduid),
"%02x%02x%02x%02x%02x%02x%02x%02x", cmd.bootduid[0],
cmd.bootduid[1], cmd.bootduid[2], cmd.bootduid[3], cmd.bootduid[4],
cmd.bootduid[5], cmd.bootduid[6], cmd.bootduid[7]);
printf("probing disks\n");
rootdevs[0] = '\0';
ptr = disknames;
while ((devname = strsep(&ptr, ",")) != NULL) {
char *duid;
duid = strchr(devname, ':');
if (duid == NULL)
continue;
*duid++ = '\0';
/* Disk without a duid cannot be a root device. */
if (strlen(duid) == 0)
continue;
/* If we have a bootduid match, nail it down! */
if (strcmp(duid, bootduid) == 0) {
snprintf(cmd.bootdev, sizeof(cmd.bootdev),
"%sa", devname);
}
/* Otherwise pick the first potential root disk. */
if (disk_proberoot(devname)) {
if (memcmp(cmd.bootduid, zeroduid, 8) == 0) {
snprintf(cmd.bootdev, sizeof(cmd.bootdev),
"%sa", devname);
}
(void)strlcat(rootdevs, " ", sizeof(rootdevs));
(void)strlcat(rootdevs, devname, sizeof(rootdevs));
}
}
if (strlen(rootdevs) != 0)
printf("available root devices:%s\n", rootdevs);
else
printf("no root devices found\n");
}
int
disk_proberoot(const char *devname)
{
static const char *const names[] = {
"bin", "dev", "etc", "home", "mnt", "root", "sbin", "tmp",
"usr", "var", NULL
};
struct ufs_args ffs_args;
struct stat st;
char path[32];
int i, is_root = 1;
snprintf(path, sizeof(path), "/dev/%sa", devname);
memset(&ffs_args, 0, sizeof(ffs_args));
ffs_args.fspec = path;
if (mount(MOUNT_FFS, "/mnt", MNT_RDONLY, &ffs_args) == -1)
return 0;
for (i = 0; names[i] != NULL; i++) {
snprintf(path, sizeof(path), "/mnt/%s", names[i]);
if (stat(path, &st) == -1 || !S_ISDIR(st.st_mode)) {
is_root = 0;
break;
}
}
(void)unmount("/mnt", 0);
return is_root;
}
const char *
disk_open(const char *path)
{
struct ufs_args ffs_args;
struct disklabel label;
char devname[32];
char *devpath;
const char *ptr;
int fd;
if (mounted) {
fprintf(stderr, "%s: cannot nest\n", __func__);
return NULL;
}
ptr = strchr(path, ':');
if (ptr != NULL) {
snprintf(devname, sizeof(devname), "%.*s",
(int)(ptr - path), path);
ptr++; /* skip ':' */
} else {
strlcpy(devname, cmd.bootdev, sizeof(devname));
ptr = path;
}
if (strlen(devname) == 0) {
fprintf(stderr, "no device specified\n");
return NULL;
}
cmd.hasduid = 0;
fd = opendev(devname, O_RDONLY, OPENDEV_BLCK, &devpath);
if (fd != -1) {
if (ioctl(fd, DIOCGDINFO, &label) != -1) {
memcpy(cmd.bootduid, label.d_uid, 8);
cmd.hasduid = 1;
}
close(fd);
} else {
fprintf(stderr, "failed to open device %s: %s\n", devname,
strerror(errno));
return NULL;
}
memset(&ffs_args, 0, sizeof(ffs_args));
ffs_args.fspec = devpath;
if (mount(MOUNT_FFS, "/mnt", MNT_FORCE | MNT_NOATIME,
&ffs_args) == -1) {
fprintf(stderr, "failed to mount %s: %s\n", devpath,
strerror(errno));
return NULL;
}
if (chroot("/mnt") == -1) {
fprintf(stderr, "failed to chroot: %s\n", strerror(errno));
(void)unmount("/mnt", 0);
return NULL;
}
mounted = 1;
return ptr;
}
void
disk_close(void)
{
if (mounted) {
(void)fchdir(rdroot);
(void)chroot(".");
mounted = 0;
(void)unmount("/mnt", 0);
}
}
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