xref: /kvmtool/disk/blk.c (revision d62e8ee002eb1ef50d0ca9dfa4f0c04782e53879)
1708dc6cbSAsias He #include "kvm/disk-image.h"
2708dc6cbSAsias He 
39f9207c5SSasha Levin #include <linux/err.h>
458fd2b7bSAsias He #include <mntent.h>
59f9207c5SSasha Levin 
6708dc6cbSAsias He /*
7708dc6cbSAsias He  * raw image and blk dev are similar, so reuse raw image ops.
8708dc6cbSAsias He  */
9063e87a0SAsias He static struct disk_image_operations blk_dev_ops = {
10dcd3cd8eSAsias He 	.read	= raw_image__read,
11dcd3cd8eSAsias He 	.write	= raw_image__write,
12*d62e8ee0SJean-Philippe Brucker 	.async	= true,
13708dc6cbSAsias He };
14708dc6cbSAsias He 
1558fd2b7bSAsias He static bool is_mounted(struct stat *st)
1658fd2b7bSAsias He {
1758fd2b7bSAsias He 	struct stat st_buf;
1858fd2b7bSAsias He 	struct mntent *mnt;
1958fd2b7bSAsias He 	FILE *f;
2058fd2b7bSAsias He 
2158fd2b7bSAsias He 	f = setmntent("/proc/mounts", "r");
2258fd2b7bSAsias He 	if (!f)
2358fd2b7bSAsias He 		return false;
2458fd2b7bSAsias He 
2558fd2b7bSAsias He 	while ((mnt = getmntent(f)) != NULL) {
2658fd2b7bSAsias He 		if (stat(mnt->mnt_fsname, &st_buf) == 0 &&
2758fd2b7bSAsias He 		    S_ISBLK(st_buf.st_mode) && st->st_rdev == st_buf.st_rdev) {
2858fd2b7bSAsias He 			fclose(f);
2958fd2b7bSAsias He 			return true;
3058fd2b7bSAsias He 		}
3158fd2b7bSAsias He 	}
3258fd2b7bSAsias He 
3358fd2b7bSAsias He 	fclose(f);
3458fd2b7bSAsias He 	return false;
3558fd2b7bSAsias He }
3658fd2b7bSAsias He 
375236b505SAsias He struct disk_image *blkdev__probe(const char *filename, int flags, struct stat *st)
38708dc6cbSAsias He {
399f9207c5SSasha Levin 	int fd, r;
4058fd2b7bSAsias He 	u64 size;
41708dc6cbSAsias He 
42708dc6cbSAsias He 	if (!S_ISBLK(st->st_mode))
439f9207c5SSasha Levin 		return ERR_PTR(-EINVAL);
44708dc6cbSAsias He 
4558fd2b7bSAsias He 	if (is_mounted(st)) {
4658fd2b7bSAsias He 		pr_err("Block device %s is already mounted! Unmount before use.",
4758fd2b7bSAsias He 		       filename);
4858fd2b7bSAsias He 		return ERR_PTR(-EINVAL);
4958fd2b7bSAsias He 	}
5058fd2b7bSAsias He 
51063e87a0SAsias He 	/*
52063e87a0SAsias He 	 * Be careful! We are opening host block device!
53063e87a0SAsias He 	 * Open it readonly since we do not want to break user's data on disk.
54063e87a0SAsias He 	 */
555236b505SAsias He 	fd = open(filename, flags);
56708dc6cbSAsias He 	if (fd < 0)
579f9207c5SSasha Levin 		return ERR_PTR(fd);
58708dc6cbSAsias He 
59708dc6cbSAsias He 	if (ioctl(fd, BLKGETSIZE64, &size) < 0) {
609f9207c5SSasha Levin 		r = -errno;
61708dc6cbSAsias He 		close(fd);
629f9207c5SSasha Levin 		return ERR_PTR(r);
63708dc6cbSAsias He 	}
64708dc6cbSAsias He 
65063e87a0SAsias He 	/*
66063e87a0SAsias He 	 * FIXME: This will not work on 32-bit host because we can not
67063e87a0SAsias He 	 * mmap large disk. There is not enough virtual address space
68063e87a0SAsias He 	 * in 32-bit host. However, this works on 64-bit host.
69063e87a0SAsias He 	 */
70*d62e8ee0SJean-Philippe Brucker 	return disk_image__new(fd, size, &blk_dev_ops, DISK_IMAGE_REGULAR);
71708dc6cbSAsias He }
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