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f3probe: make sure that the block device is a disk

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This patch makes f3probe test that the block device passed is
a disk, not a partition or something else.
If the block device is a partition,
the correct disk device is reported.

Example of this new protection in action:
$ sudo f3probe /dev/sdb1
[sudo] password for michel:
F3 probe 4.0
Copyright (C) 2010 Digirati Internet LTDA.
This is free software; see the source for copying conditions.

Device `/dev/sdb1' is a partition of disk device `/dev/sdb'.
You can run this program as follows:
f3probe /dev/sdb

Application cannot continue, finishing...
This commit is contained in:
Michel Machado 2014-12-17 08:37:18 -05:00
parent 783ef37213
commit dd6ebe6b99
1 changed files with 73 additions and 20 deletions
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93
libdevs.c
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@ -335,8 +335,6 @@ static struct udev_device *map_dev_to_usb_dev(struct udev_device *dev)
*/
usb_dev = udev_device_get_parent_with_subsystem_devtype(
dev, "usb", "usb_device");
if (!usb_dev)
err(errno, "Unable to find parent device");
/* @usb_dev is not referenced, and will be freed when
* the child (i.e. @dev) is freed.
@ -346,13 +344,21 @@ static struct udev_device *map_dev_to_usb_dev(struct udev_device *dev)
return udev_device_ref(usb_dev);
}
static struct udev_device *map_block_to_usb_dev(struct udev *udev, int block_fd)
static struct udev_device *dev_from_block_fd(struct udev *udev, int block_fd)
{
struct stat fd_stat;
struct udev_device *dev, *usb_dev;
assert(!fstat(block_fd, &fd_stat));
dev = udev_device_new_from_devnum(udev, 'b', fd_stat.st_rdev);
if (!S_ISBLK(fd_stat.st_mode))
err(EINVAL, "FD %i is not a block device", block_fd);
return udev_device_new_from_devnum(udev, 'b', fd_stat.st_rdev);
}
static struct udev_device *map_block_to_usb_dev(struct udev *udev, int block_fd)
{
struct udev_device *dev, *usb_dev;
dev = dev_from_block_fd(udev, block_fd);
assert(dev);
usb_dev = map_dev_to_usb_dev(dev);
assert(!udev_device_unref(dev));
@ -451,7 +457,9 @@ static int bdev_manual_usb_reset(struct device *dev)
/* Obtain @bus_num and @dev_num of the USB device to monitor. */
usb_dev = map_block_to_usb_dev(udev, bdev->fd);
assert(usb_dev);
if (!usb_dev)
errx(1, "Unable to find USB parent device of block device `%s'",
bdev->filename);
devnode = udev_device_get_devnode(usb_dev);
id_vendor = udev_device_get_sysattr_value(usb_dev, "idVendor");
id_product = udev_device_get_sysattr_value(usb_dev, "idProduct");
@ -539,24 +547,27 @@ static void bdev_free(struct device *dev)
free((void *)bdev->filename);
}
static bool is_block_dev(int fd)
static struct udev_device *map_partition_to_disk(struct udev_device *dev)
{
struct stat stat;
assert(!fstat(fd, &stat));
return S_ISBLK(stat.st_mode);
struct udev_device *disk_dev;
disk_dev = udev_device_get_parent_with_subsystem_devtype(
dev, "block", "disk");
/* @disk_dev is not referenced, and will be freed when
* the child (i.e. @dev) is freed.
* See udev_device_get_parent_with_subsystem_devtype() for
* details.
*/
return udev_device_ref(disk_dev);
}
/* XXX Test if it's a device, or a partition.
* If a partition, warn user, and ask for confirmation before
* going ahead.
* Suggest how to call f3probe with the correct device name if
* the block device is a partition.
* Use udev to do these tests.
* Make sure that no partition of the drive is mounted.
*/
struct device *create_block_device(const char *filename, enum reset_type rt)
{
struct block_device *bdev;
struct udev *udev;
struct udev_device *fd_dev, *usb_dev;
const char *s;
int block_size;
bdev = malloc(sizeof(*bdev));
@ -580,10 +591,48 @@ struct device *create_block_device(const char *filename, enum reset_type rt)
goto filename;
}
if (!is_block_dev(bdev->fd)) {
err(EINVAL, "File `%s' is not a block device", filename);
/* Make sure that @bdev->fd is a disk, not a partition, and that
* it is in fact backed by a USB device.
*/
udev = udev_new();
if (!udev) {
warn("Can't create udev");
goto fd;
}
fd_dev = dev_from_block_fd(udev, bdev->fd);
if (!fd_dev) {
fprintf(stderr, "Can't create udev device from `%s'\n",
filename);
goto udev;
}
assert(!strcmp(udev_device_get_subsystem(fd_dev), "block"));
s = udev_device_get_devtype(fd_dev);
if (!strcmp(s, "partition")) {
struct udev_device *disk_dev = map_partition_to_disk(fd_dev);
assert(disk_dev);
s = udev_device_get_devnode(disk_dev);
fprintf(stderr, "Device `%s' is a partition of disk device `%s'.\n"
"You can run this program as follows:\nf3probe %s\n",
filename, s, s);
/* For some reason, there already was a reference to @disk_dev
* before the call map_partition_to_disk().
*/
assert(udev_device_unref(disk_dev) == disk_dev);
goto fd_dev;
} else if (strcmp(s, "disk")) {
fprintf(stderr, "Device `%s' is not a disk, but `%s'",
filename, s);
goto fd_dev;
}
usb_dev = map_dev_to_usb_dev(fd_dev);
if (!usb_dev) {
fprintf(stderr, "Device `%s' is not backed by a USB device",
filename);
goto fd_dev;
}
assert(!udev_device_unref(usb_dev));
assert(!udev_device_unref(fd_dev));
assert(!udev_unref(udev));
switch (rt) {
case RT_MANUAL_USB:
@ -608,6 +657,10 @@ struct device *create_block_device(const char *filename, enum reset_type rt)
return &bdev->dev;
fd_dev:
assert(!udev_device_unref(fd_dev));
udev:
assert(!udev_unref(udev));
fd:
assert(!close(bdev->fd));
filename: