This is just a convenience method for discarding a list of filters instead of
using a 'for' loop everywhere. It is safe to pass -1 as the number of elements
in the list as well as passing NULL as list reference.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Provide a separate method to free a logging filter object. This will come handy
once a method to create an individual logging filter object is introduced.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

This is just a convenience method for discarding a list of outputs instead of
using a 'for' loop everywhere. It is safe to pass -1 as the number of elements
in the list as well as passing NULL as list reference.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Provide a separate method to free a logging output object. This will come handy
once a method to create an individual logging output object is introduced.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Usage of this keyword in front of function declaration that is exported via a
header file is unnecessary, since internally, this has been the default for most
compilers for quite some time.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

In order to refactor the ugly virLogParseOutputs method, this is a neat way of
finding out whether the destination type (in the form of a string) user
provided is a valid one. As a bonus, if it turns out it is valid, we get the
actual enum which will later be passed to any of virLogAddOutput methods right
away.

It is often helpful to know which version of libvirt and QEMU
was present when a guest was first launched. Ensure this info
is written into the QEMU log file for each guest.

A earlier commit changed the global log buffer so that it only
records messages that are explicitly requested via the log
filters setting. This removes the performance burden, and
improves the signal/noise ratio for messages in the global
buffer. At the same time though, it is somewhat pointless, since
all the recorded log messages are already going to be sent to an
explicit log output like syslog, stderr or the journal. The
global log buffer is thus just duplicating this data on stderr
upon crash.

The log_buffer_size config parameter is left in the augeas
lens to prevent breakage for users on upgrade. It is however
completely ignored hereafter.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Currently the log filter strings are used in a string comparison
against the source filename each time log message is emitted.
If no log filters at all are set, there's obviously no string
comparison to be done. If any single log filter is set though,
this imposes a compute burden on every logging call even if logs
from the file in question are disabled. This string comparison
must also be done while the logging mutex is held, which has
implications for concurrency when multiple threads are emitting
log messages.

This changes the log filtering to be done based on the virLogSource
object name. The virLogSource struct is extended to contain
'serial' and 'priority' fields. Any time the global log filter
rules are changed a global serial number is incremented. When a
log message is emitted, the serial in the virLogSource instance
is compared with the global serial number. If out of date, then
the 'priority' field in the virLogSource instance is updated based
on the new filter rules. The 'priority' field is checked to see
whether the log message should be sent to the log outputs.

The comparisons of the 'serial' and 'priority' fields are done
with no locks held. So in the common case each logging call has
an overhead of 2 integer comparisons, with no locks held. Only
if the decision is made to forward the message to the log output,
or if the 'serial' value is out of date do locks need to be
acquired.

Technically the comparisons of the 'serial' and 'priority' fields
should be done with locks held, or using atomic operations. Both
of these options have a notable performance impact, however, and
since all writes a protected by a global mutex, it is believed
that worst case behaviour where the fields are read concurrently
with being written would merely result in an mistaken emission
or dropping of the log message in question. This is an acceptable
tradeoff for the performance benefit of avoiding locking.

As a quick benchmark, a demo program that registers 500 file
descriptors with the event loop (eg equiv of 500 QEMU monitor
commands), creates pending read I/O on every FD, and then runs
virEventRunDefaultImpl() took 4.6 seconds to do 51200 iterations.
After this optimization it only takes 3.3 seconds, with the log
APIs no longer being a relevant factor in the running time.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Any source file which calls the logging APIs now needs
to have a VIR_LOG_INIT("source.name") declaration at
the start of the file. This provides a static variable
of the virLogSource type.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

As part of the goal to get away from doing string matching on
filenames when deciding whether to emit a log message, turn
the virLogSource enum into a struct which contains a log
"name". There will eventually be one virLogSource instance
statically declared per source file. To minimise churn in this
commit though, a single global instance is used.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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

Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Call virLogVMessage instead of virLogMessage, since libudev
called us with a va_list object, not a list of arguments.

Honor message priority and strip the trailing newline.

https://bugzilla.redhat.com/show_bug.cgi?id=969152

When reading log output from QEMU/LXC we need to skip over any
libvirt log messages. Currently the QEMU driver checks for a
fixed string, but this is better done with a regex. Add a method
virLogProbablyLogMessage to do a regex check
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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

... and update all users.  No change in functionality, the parameter
will be used in the next patch.
Signed-off-by: NMiloslav Trmač <mitr@redhat.com>

... and update all users.  No change in functionality, the parameter
will be used later.

The metadata representation is as minimal as possible, but requires
the caller to allocate an array on stack explicitly.

The alternative of using varargs in the virLogMessage() callers:
* Would not allow the caller to optionally omit some metadata elements,
  except by having two calls to virLogMessage.
* Would not be as type-safe (e.g. using int vs. size_t), and the compiler
  wouldn't be able to do type checking
* Depending on parameter order:
  a) virLogMessage(..., message format, message params...,
                   metadata..., NULL)
     can not be portably implemented (parse_printf_format() is a glibc
     function)
  b) virLogMessage(..., metadata..., NULL,
                   message format, message params...)
     would prevent usage of ATTRIBUTE_FMT_PRINTF and the associated
     compiler checking.
Signed-off-by: NMiloslav Trmač <mitr@redhat.com>

Commit e8fd8757 changed 'const char *'
category to virLogSource enum. This changes it in virLogEatParams as
well, thus fixing the build with --disable-debug.
--
Hopefully moving the enum declarations is less ugly than using int.

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>

The 'const char *category' parameter only has a few possible
values now that the filename has been separated. Turn this
parameter into an enum instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Currently the logging APIs have a 'const char *category' parameter
which indicates where the log message comes from. This is typically
a combination of the __FILE__ string and other prefix. Split the
__FILE__ off into a dedicated parameter so it can passed to the
log outputs
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

General whitespace cleanup in the logging files

 - Move '{' to a new line after funtion declaration
 - Put each parameter on a new line to avoid long lines
 - Put return type on new line
 - Leave 2 blank lines between functions
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The log destinations are an enum, but most of the code was
just using a plain 'int' for function params / variables.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The __LINE__ macro value is specified to fit in the size_t
type, so use that instead of 'long long' in the logging code
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The log priority levels are an enum, but most of the code was
just using a plain 'int' for function params / variables.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

In addition to the preformatted text line, pass the raw message as well,
to allow the output functions to use a different output format.
Signed-off-by: NMiloslav Trmač <mitr@redhat.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Nothing uses the return value, and creating it requries otherwise
unnecessary strlen () calls.

This cleanup is conceptually independent from the rest of the series
(although the later patches won't apply without it).  This just seems
a good opportunity to clean this up, instead of entrenching the unnecessary
return value in the virLogOutputFunc instance that will be added in this
series.
Signed-off-by: NMiloslav Trmač <mitr@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/

Remove the use of a manually run virLogStartup and
virNodeSuspendInitialize methods. Instead make sure they
are automatically run using VIR_ONCE_GLOBAL_INIT
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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

When building with --disable-debug, VIR_DEBUG expands to a nop.
But parameters to VIR_DEBUG can be variables that are passed only
to VIR_DEBUG. In the case the building system complains about unused
variables.

Allow the logging APIs to be called with a va_list for format
args, instead of requiring var-args usage.

* src/util/logging.h, src/util/logging.c: Add virLogVMessage

Sometimes it is useful to see the callpath for log messages.
This change enhances the log filter syntax so that stack traces
can be show by setting '1:+NAME' instead of '1:NAME'.

This results in output like:

2012-05-09 14:18:45.136+0000: 13314: debug : virInitialize:414 : register drivers
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(virInitialize+0xd6)[0x7f89188ebe86]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x431921]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x3a21e21735]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x40a279]

2012-05-09 14:18:45.136+0000: 13314: debug : virRegisterDriver:775 : driver=0x7f8918d02760 name=Test
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(virRegisterDriver+0x6b)[0x7f89188ec717]
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(+0x11b3ad)[0x7f891891e3ad]
/home/berrange/src/virt/libvirt/src/.libs/libvirt.so.0(virInitialize+0xf3)[0x7f89188ebea3]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x431921]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x3a21e21735]
/home/berrange/src/virt/libvirt/tools/.libs/lt-virsh[0x40a279]

* docs/logging.html.in: Document new syntax
* configure.ac: Check for execinfo.h
* src/util/logging.c, src/util/logging.h: Add support for
  stack traces
* tests/testutils.c: Adapt to API change
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Syslog puts the timestamp to every message anyway so this removes
redundant data.

Silently ignored flags get in the way of new features that
use those flags.  Also, an upcoming syntax check will favor
unsigned flags.

* src/nodeinfo.h (nodeGetCPUStats, nodeGetMemoryStats): Drop
unused attribute.
* src/interface/netcf_driver.c (interfaceOpenInterface)
(interfaceDefineXML, interfaceCreate, interfaceDestroy): Reject
unknown flags.
* src/network/bridge_driver.c (networkOpenNetwork)
(networkGetXMLDesc): Likewise.
* src/nwfilter/nwfilter_driver.c (nwfilterOpen): Likewise.
* src/secret/secret_driver.c (secretOpen, secretDefineXML)
(secretGetXMLDesc, secretSetValue): Likewise.
* src/util/logging.c (virLogDefineFilter, virLogDefineOutput)
(virLogMessage): Likewise; also use unsigned flags.
* src/util/logging.h (virLogDefineFilter, virLogDefineOutput)
(virLogMessage): Change signature.
* src/util/command.c (virExecWithHook): Likewise.

Use of ',##__VA_ARGS__' is a gcc extension not guaranteed by
C99; thankfully, we can avoid it by lumping the format argument
into the var-args set.

* src/util/logging.h (VIR_DEBUG_INT, VIR_INFO_INT, VIR_WARN_INT)
(VIR_ERROR_INT, VIR_DEBUG, VIR_INFO, VIR_WARN, VIR_ERROR): Stick
to C99 var-arg macro syntax.
* examples/domain-events/events-c/event-test.c (VIR_DEBUG):
Simplify.

These VIR_XXXX0 APIs make us confused, use the non-0-suffix APIs instead.

How do these coversions works? The magic is using the gcc extension of ##.
When __VA_ARGS__ is empty, "##" will swallow the "," in "fmt," to
avoid compile error.

example: origin				after CPP
	high_level_api("%d", a_int)	low_level_api("%d", a_int)
	high_level_api("a  string")	low_level_api("a  string")

About 400 conversions.

8 special conversions:
VIR_XXXX0("") -> VIR_XXXX("msg") (avoid empty format) 2 conversions
VIR_XXXX0(string_literal_with_%) -> VIR_XXXX(%->%%) 0 conversions
VIR_XXXX0(non_string_literal) -> VIR_XXXX("%s", non_string_literal)
  (for security) 6 conversions
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>

This is the part allowing to dynamically resize the debug log
buffer from it's default 64kB size. The buffer is now dynamically
allocated.
It adds a new API virLogSetBufferSize() which resizes the buffer
If passed a zero size, the buffer is deallocated and we do the small
optimization of not formatting messages which are not output anymore.
On the daemon side, it just adds a new option log_buffer_size to
libvirtd.conf and call virLogSetBufferSize() if needed
* src/util/logging.h src/util/logging.c src/libvirt_private.syms:
  make buffer dynamic and add virLogSetBufferSize() internal API
* daemon/libvirtd.conf: document the new log_buffer_size option
* daemon/libvirtd.c: read and use the new log_buffer_size option