hacking: Add some text around the running of Valgrind along with example
output for "real" vs. "false positives".

cfg.mk: Add hacking.in.html to sc_prohibit_raw_allocation

After one last-minute change, only HACKING was updated and not
hacking.html.in, so this patch synchronizes that.

Adding dots inside "exempli gratia" where missing.  While on that, I
took the liberty of changing it where found with simple grep.

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

I've noticed a number of people sending patches with file
renames not compressed, so we might as well document how to
set this up.  (Git won't do it by default, for back-compat
reasons)

* docs/hacking.html.in: Add git config tip.
* HACKING: Regenerate.

Based on a suggestion by John Ferlan:
https://www.redhat.com/archives/libvir-list/2013-January/msg00158.html

* docs/hacking.html.in: Add some commit message instructions.
Mention the ./run script.
* HACKING: Regenerate.

This documents the following whitespace rules

      if(foo)   // Bad
      if (foo)  // Good

      int foo (int wizz)  // Bad
      int foo(int wizz)   // Good

      bar = foo (wizz);  // Bad
      bar = foo(wizz);   // Good

      typedef int (*foo) (int wizz);  // Bad
      typedef int (*foo)(int wizz);   // Good

      int foo( int wizz );  // Bad
      int foo(int wizz);    // Good

There is a syntax-check rule extension to validate all these rules.
Checking for 'function (...args...)' is quite difficult since it
needs to ignore valid usage with keywords like 'if (...test...)'
and while/for/switch. It must also ignore source comments and
quoted strings.

It is not possible todo this with a simple regex in the normal
syntax-check style. So a short Perl script is created instead
to analyse the source. In practice this works well enough. The
only thing it can't cope with is multi-line quoted strings of
the form

 "start of string\
more lines\
more line\
the end"

but this can and should be written as

 "start of string"
 "more lines"
 "more line"
 "the end"

with this simple change, the bracket checking script does not
have any false positives across libvirt source, provided it
is only run against .c files. It is not practical to run it
against .h files, since those use whitespace extensively to
get alignment (though this is somewhat inconsistent and could
arguably be fixed).

The only limitation is that it cannot detect a violation where
the first arg starts with a '*', eg

   foo(*wizz);

since this generates too many false positives on function
typedefs which can't be supressed efficiently.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

--enable-compile-warnings=error has been renamed to --enable-werror so
update the HACKING and the hacking.html to reflect that.

Two sections didn't have a working link in the TOC.

An email came to libvir-list wondering why the git send-email command
was missing in spite of having git installed; this is due to the
send-email command being in a sub-package of the main git package.

While touching the hacking file, I thought it would be useful to 1)
indicate the location of the source (docs/hacking.html.in) in the
message at the top of HACKING, and also to make the note about running
"make check" and "make syntax-check" a bit more stern.

We should really advise (new) developers to send rebased patches
that apply cleanly and use git-send-email rather than all other
obscure ways.

In preparation for a future patch adding new virFile APIs.

* src/util/files.h, src/util/files.c: Move...
* src/util/virfile.h, src/util/virfile.c: ...here, and rename
functions to virFile prefix.  Macro names are intentionally
left alone.
* *.c: All '#include "files.h"' uses changed.
* src/Makefile.am (UTIL_SOURCES): Reflect rename.
* cfg.mk (exclude_file_name_regexp--sc_prohibit_close): Likewise.
* src/libvirt_private.syms: Likewise.
* docs/hacking.html.in: Likewise.
* HACKING: Regenerate.

We already have virAsprintf, so picking a similar name helps for
seeing a similar purpose.  Furthermore, the prefix V before printf
generally implies 'va_list', even though this variant was '...', and
the old name got in the way of adding a new va_list version.

global rename performed with:

$ git grep -l virBufferVSprintf \
  | xargs -L1 sed -i 's/virBufferVSprintf/virBufferAsprintf/g'

then revert the changes in ChangeLog-old.

* docs/hacking.html.in (Code formatting): Document that // comment
and declaration-after-statement are discouraged.
* HACKING: Regenerate.

* docs/hacking.html.in (Curly braces): Tighten recommendations to
disallow if (cond) one-line; else { block; }.
* HACKING: Regenerate.
Suggested by Daniel P. Berrange.

* daemon/libvirtd.c (qemudRunLoop): Pass allocation size, not
current count, to VIR_SHRINK_N.
* docs/hacking.html.in: Update doc example.
* HACKING: Regenerate.

* src/util/memory.h (VIR_RESIZE_N): New macro.
* src/util/memory.c (virResizeN): New function.
* src/libvirt_private.syms: Export new helper.
* docs/hacking.html.in: Document it.
* HACKING: Regenerate.

* src/util/memory.h (VIR_REALLOC_N): Update docs.
(VIR_EXPAND_N, VIR_SHRINK_N): New macros.
(virAlloc, virAllocN, virReallocN, virAllocVar, virFree): Add some
gcc attributes.
* src/util/memory.c (virExpandN, virShrinkN): New functions.
(virReallocN): Update docs.
* src/libvirt_private.syms: Export new helpers.
* docs/hacking.html.in: Prefer newer interfaces over
VIR_REALLOC_N, since uninitialized memory can bite us.
* HACKING: Regenerate.

* cfg.mk (sc_prohibit_sprintf): New rule.
(sc_prohibit_asprintf): Avoid false positives.
* docs/hacking.html.in (Printf-style functions): Document the
policy.
* HACKING: Regenerate.
* .x-sc_prohibit_sprintf: New exemptions.
* Makefile.am (syntax_check_exceptions): Ship new file.
* src/vbox/vbox_tmpl.c (vboxStartMachine, vboxAttachUSB): Use
virAsprintf instead.
* src/uml/uml_driver.c (umlOpenMonitor): Use snprintf instead.
* tools/virsh.c (cmdDetachInterface): Likewise.
* src/security/security_selinux.c (SELinuxGenSecurityLabel):
Likewise.
* src/openvz/openvz_driver.c (openvzDomainDefineCmd): Likewise,
and ensure large enough buffer.

Similarly to deprecating close(), I am now deprecating fclose() and
introduce VIR_FORCE_FCLOSE() and VIR_FCLOSE(). Also, fdopen() is replaced with
VIR_FDOPEN().

Most of the files are opened in read-only mode, so usage of
VIR_FORCE_CLOSE() seemed appropriate. Others that are opened in write
mode already had the fclose()<  0 check and I converted those to
VIR_FCLOSE()<  0.

I did not find occurrences of possible double-closed files on the way.

Tweak pre tags to achieve proper indentation of their
plaintext representation. Also use more b/i/code tags.

Since bugs due to double-closed file descriptors are difficult to track down in a multi-threaded system, I am introducing the VIR_CLOSE(fd) macro to help avoid mistakes here.

There are lots of places where close() is being used. In this patch I am only cleaning up usage of close() in src/conf where the problems were.

I also dare to declare close() as being deprecated in libvirt code base (HACKING).

* docs/hacking.html.in: Use the "curly braces" section from coreutils'
HACKING, adapting for libvirt's different formatting style.
* HACKING: Sync from the above, still mostly manually.

xsltproc complained about this.

* HACKING: Mark as read-only.  Soon we'll generate it from...
* docs/hacking.html.in: ... this file.  More typo fixes.

* doc/hacking.html.in (preprocessor): New section to document
recently-discussed style issues.
Signed-off-by: NEric Blake <eblake@redhat.com>

* docs/hacking.html.in (committers): Fix spelling and grammar.

* Added section on use of goto
* Added missing content from HACKING document

Instead of refering to __virRaiseError(VIR_ERROR_NO_MEMORY).

* HACKING: STRCASEEQ is case insensitive.
* docs/hacking.html.in: Likewise.

Replace free(virBufferContentAndReset()) with virBufferFreeAndReset().
Update documentation and replace all remaining calls to free() with
calls to VIR_FREE(). Also add missing calls to virBufferFreeAndReset()
and virReportOOMError() in OOM error cases.

This patch is the result of running the following command in the docs
directory: sed -i 's/\t/        /g; s/\s*$//' *.html.in

* docs/*.html.in:convert tabs into 8 spaces and remove trailing whitespace