Normally when a process' uid is changed to non-0, all the capabilities
bits are cleared, even those explicitly set with calls to
capng_update()/capng_apply() made immediately before setuid. And
*after* the process' uid has been changed, it no longer has the
necessary privileges to add capabilities back to the process.

In order to set a non-0 uid while still maintaining any capabilities
bits, it is necessary to either call capng_change_id() (which
unfortunately doesn't currently call initgroups to setup auxiliary
group membership), or to perform the small amount of calisthenics
contained in the new utility function virSetUIDGIDWithCaps().

Another very important difference between the capabilities
setting/clearing in virSetUIDGIDWithCaps() and virCommand's
virSetCapabilities() (which it will replace in the next patch) is that
the new function properly clears the capabilities bounding set, so it
will not be possible for a child process to set any new
capabilities.

A short description of what is done by virSetUIDGIDWithCaps():

1) clear all capabilities then set all those desired by the caller (in
capBits) plus CAP_SETGID, CAP_SETUID, and CAP_SETPCAP (which is needed
to change the capabilities bounding set).

2) call prctl(), telling it that we want to maintain current
capabilities across an upcoming setuid().

3) switch to the new uid/gid

4) again call prctl(), telling it we will no longer want capabilities
maintained if this process does another setuid().

5) clear the capabilities that we added to allow us to
setuid/setgid/change the bounding set (unless they were also requested
by the caller via the virCommand API).

Because the modification/maintaining of capabilities is intermingled
with setting the uid, this is necessarily done in a single function,
rather than having two independent functions.

Note that, due to the way that effective capabilities are computed (at
time of execve) for a process that has uid != 0, the *file*
capabilities of the binary being executed must also have the desired
capabilities bit(s) set (see "man 7 capabilities"). This can be done
with the "filecap" command. (e.g. "filecap /usr/bin/qemu-kvm sys_rawio").

Rather than treating uid:gid of 0:0 as a NOP, we blindly pass that
through to the lower layers. However, we *do* check for a requested
value of "-1" to mean "don't change this setting". setregid() and
setreuid() already interpret -1 as a NOP, so this is just an
optimization, but we are also calling getpwuid_r and initgroups, and
it's unclear what the former would do with a uid of -1.

Currently, whenever somebody calls saferead() on nonblocking FD
(safewrite() is totally interchangeable for purpose of this message)
he might get wrong return value. For instance, in the first iteration
some data is read. The number of bytes read is stored into local
variable 'nread'. However, in next iterations we can get -1 from
read() with errno == EAGAIN, in which case the -1 is returned despite
fact some data has already been read. So the caller gets confused.
Bare read() should be used for nonblocking FD.

Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

There's no need to do lots of readlink() calls to canonicalize
a name if we're only going to use stat() on it, since stat()
already chases symlinks.

* src/util/virutil.c (virGetDeviceID): Let stat() do the symlink
chasing.

This ignores the default "filtered" if unpriv_sgio is not supported
by kernel, but for explicit request "filtered", it error out for
domain starting.

"virGetDeviceID" could be used across the sources, but it doesn't
relate with this series, and could be done later.

* src/util/virutil.h: (Declare virGetDeviceID, and
                       vir{Get,Set}DeviceUnprivSGIO)
* src/util/virutil.c: (Implement virGetDeviceID and
                       vir{Get,Set}DeviceUnprivSGIO)
* src/libvirt_private.syms: Export private symbols of upper helpers

Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

I didn't notice the extra "does" in the previous patch. Remove it.

This patch gets rid of the undeterministic error reporting code done on
return values of get(pw|gr)nam_r. With this patch, if the group record
is not returned by the corresponding function this error is not
considered fatal even if errno != 0. The error is logged in such case.

QEMU supports setting vendor and product strings for disk since
1.2.0 (only scsi-disk, scsi-hd, scsi-cd support it), this patch
exposes it with new XML elements <vendor> and <product> of disk
device.

virGetGroupIDByName is documented as returning 1 if the groupname
cannot be found. getgrnam_r is documented as returning:
« 0 or ENOENT or ESRCH or EBADF or EPERM or ...  The given name
or gid was not found. »
 and that:
« The formulation given above under "RETURN VALUE" is from POSIX.1-2001.
It  does  not  call  "not  found"  an error, hence does not specify what
value errno might have in this situation.  But that makes it impossible to
recognize errors.  One might argue that according to POSIX errno should be
left unchanged if an entry is not found.  Experiments on various UNIX-like
systems shows that lots of different values occur in this situation: 0,
ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others. »

virGetGroupIDByName returns an error when the return value of getgrnam_r
is non-0. However on my RHEL system, getgrnam_r returns ENOENT when the
requested user cannot be found, which then causes virGetGroupID not
to behave as documented (it returns an error instead of falling back
to parsing the passed-in value as an gid).

This commit makes virGetGroupIDByName only report an error when errno
is set to one of the values in the posix description of getgrnam_r
(which are the same as the ones described in the manpage on my system).

virGetUserIDByName is documented as returning 1 if the username
cannot be found. getpwnam_r is documented as returning:
« 0 or ENOENT or ESRCH or EBADF or EPERM or ...  The given name
or uid was not found. »
 and that:
« The formulation given above under "RETURN VALUE" is from POSIX.1-2001.
It  does  not  call  "not  found"  an error, hence does not specify what
value errno might have in this situation.  But that makes it impossible to
recognize errors.  One might argue that according to POSIX errno should be
left unchanged if an entry is not found.  Experiments on various UNIX-like
systems shows that lots of different values occur in this situation: 0,
ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others. »

virGetUserIDByName returns an error when the return value of getpwnam_r
is non-0. However on my RHEL system, getpwnam_r returns ENOENT when the
requested user cannot be found, which then causes virGetUserID not
to behave as documented (it returns an error instead of falling back
to parsing the passed-in value as an uid).

This commit makes virGetUserIDByName only report an error when errno
is set to one of the values in the posix description of getpwnam_r
(which are the same as the ones described in the manpage on my system).

The docs for virDiskNameToIndex claim it ignores partition
numbers. In actual fact though, a code ordering bug means
that a partition number will cause the code to accidentally
multiply the result by 26.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The libvirt coding standard is to use 'function(...args...)'
instead of 'function (...args...)'. A non-trivial number of
places did not follow this rule and are fixed in this patch.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Currently virNetSocketNew fails because virSetCloseExec fails as there
is no proper implementation for it on Windows at the moment. Workaround
this by pretending that setting close-on-exec on the fd works. This can
be done because libvirt currently lacks the ability to create child
processes on Windows anyway. So there is no point in failing to set a
flag that isn't useful at the moment anyway.

This patch updates virGetUserID and virGetGroupID to be able to parse a
user or group name in a similar way to coreutils' chown. This means that
a numeric value with a leading plus sign is always parsed as an ID,
otherwise the functions try to parse the input first as a user or group
name and if this fails they try to parse it as an ID.

This patch includes Peter Krempa's changes to correctly handle errors
returned by getpwnam_r and getgrnam_r.

Add support for logging to the systemd journal, using its
simple client library. The benefit over syslog is that it
accepts structured log data, so the journald can store
individual items like code file/line/func separately from
the string message. Tools which require structured log
data can then query the journal to extract exactly what
they desire without resorting to string parsing

While systemd provides a simple client library for logging,
it is more convenient for libvirt to directly write its
own client code. This lets us build up the iovec's on
the stack, avoiding the need to alloc memory when writing
log messages.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Continue consolidation of process functions by moving some
helpers out of command.{c,h} into virprocess.{c,h}
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

There are a number of process related functions spread
across multiple files. Start to consolidate them by
creating a virprocess.{c,h} file
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Change "Pid" to "Process" to align with the virProcessKill
API naming prefix
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Changing naming to follow the convention of "object" followed
by "action"
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

Validates the wwn while parsing, error out if it's malformed.

* src/util/util.h: Declare virValidateWWN
* src/util/util.c: Implement virValidateWWN
* src/libvirt_private.syms: Export virValidateWWN.
* src/conf/domain_conf.h: New member 'wwn' for disk def.
* src/conf/domain_conf.c: Parse and format disk <wwn>

getpwuid_r returns success but sets the return structure to NULL when it
fails to deliver data about the requested uid. In our helper code this
created following strange error messages:

" ... cannot getpwuid_r(1234): Success"

This patch creates a more helpful message:
" ... getpwuid_r failed to retrieve data for uid '1234'"

Fixes for some typos that somehow didn't get to the final push of the
commit 43bfa23e.

libvirt creates invalid commands if wrong locale is selected. For
example with locale that uses comma as a decimal point, JSON commands
created with decimal numbers are invalid because comma separates the
entries in JSON. Fortunately even when decimal point is affected,
thousands grouping is not, because for grouping to be enabled with
*printf, there has to be an apostrophe flag specified (and supported).

This patch adds specific internal function for converting doubles to
strings with C locale.

Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c

This removes nearly all the per-file error reporting macros
from the code in src/util/. A few custom macros remain for the
case, where the file needs to report errors with a variety of
different codes or parameters
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

All the callers of virDirCreate are updated incidentally.

Instead of changing the existed virFileMakePath to accept mode
argument and modifying a pile of its uses, this patch introduces
virFileMakePathWithMode, and use it instead of mkdir() to create
the readline history dir.

Some GNULIB headers (eg unistd.h) will often need to include
winsock2.h for various symbols. There is a rule that winsock2.h
must be included before windows.h. This means that any file
which does

  #ifdef WIN32
  #include <windows.h>
  #endif
  #include <unistd.h>

is potentially broken. A simple rule is that /all/ includes of
windows.h must be matched with a preceding include of winsock2.h
regardless of whether unistd.h is used currently
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>