This returns the number of whole block devices added. It is usually
simpler to call this than to list the devices and count them, which
is what we do in some places in the current codebase.
This returns the index of the device, eg. /dev/sdb => 1.
Or you can think of it as the order that the device was
added, or the index of the device in guestfs_list_devices.
The presumption is that all file descriptors should be created with
the close-on-exec flag set. The only exception are file descriptors
that we want passed through to exec'd subprocesses (mainly pipes and
stdin/stdout/stderr).
For open calls, we pass O_CLOEXEC as an extra flag, eg:
fd = open ("foo", O_RDONLY|O_CLOEXEC);
This is a Linux-ism, but using a macro we can easily make it portable.
For sockets, similarly:
sock = socket (..., SOCK_STREAM|SOCK_CLOEXEC, ...);
For accepted sockets, we use the Linux accept4 system call which
allows flags to be supplied, but we use the Gnulib 'accept4' module to
make this portable.
For dup, dup2, we use the Linux dup3 system call, and the Gnulib
modules 'dup3' and 'cloexec'.
Previously a lot of daemon code used three variables (a string list,
'int size' and 'int alloc') to track growable strings buffers. This
commit implements a simple struct containing the same variables, but
using size_t instead of int:
struct stringsbuf {
char **argv;
size_t size;
size_t alloc;
};
Use it like this:
DECLARE_STRINGSBUF (ret);
//...
if (add_string (&ret, str) == -1)
return NULL;
//...
if (end_stringsbuf (&ret) == -1)
return NULL;
return ret.argv;
This converts a partition device name (eg. /dev/sda1) to a partition
number (eg. 1). This is useful in conjunction with the parted APIs
that mostly take a disk device + partnum.
This changes the method used to build the supermin appliance
to use the new ext2-based appliance supported by latest febootstrap.
The appliance can also be cached, so we avoid rebuilding it
each time it is used.
Mailing list discussion goes into the rationale and details:
https://www.redhat.com/archives/libguestfs/2010-August/msg00028.html
Requires febootstrap >= 2.8.
mkfs-b: Pass the -b (blocksize) parameter to mkfs.
mke2journal and friends: Lets you create external ext2 journals on
devices.
mke2fs-J and friends: Lets you create ext2/3/4 filesystems with
external journals.
Nearly every file-related function in daemons/*.c is affected:
Remove this pair of statements from each affected do_* function:
- NEED_ROOT (return -1);
- ABS_PATH (dir, return -1);
and change the type of the corresponding parameter to "const char *".
* src/generator.ml: Emit NEED_ROOT just once, even when there are two or
more Pathname args.
virtio_blk is the fast, virt-native block device driver
supported by qemu and KVM. Note that virtio_blk device
names are called /dev/vd*.
Existing scripts should continue working because device name
translation will silently change device names of the form
/dev/sd* to /dev/vd* as required.
See also:
http://libguestfs.org/guestfs.3.html#block_device_naming
