[libvirt] [PATCH 2/5] util: use VIR_STRCAT instead of strcat

[Daniel P. Berrange]

On Thu, Feb 23, 2017 at 05:15:37PM +0100, Martin Kletzander wrote:
> On Thu, Feb 23, 2017 at 04:26:57PM +0100, Pavel Hrdina wrote:
> > Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
> > ---
> > cfg.mk                                | 14 ++++++++------
> > src/storage/storage_backend_logical.c |  6 +++---
> > src/test/test_driver.c                |  2 +-
> > src/util/vircgroup.c                  |  4 +---
> > src/xen/xend_internal.c               |  2 +-
> > 5 files changed, 14 insertions(+), 14 deletions(-)
> > 
> > diff --git a/cfg.mk b/cfg.mk
> > index 22c655eac6..6646509206 100644
> > --- a/cfg.mk
> > +++ b/cfg.mk
> > @@ -390,6 +390,11 @@ sc_prohibit_strdup:
> > 	halt='use VIR_STRDUP, not strdup'				\
> > 	  $(_sc_search_regexp)
> > 
> > +sc_prohibit_strcat:
> > +	@prohibit='\<strn?cat\> *\('					\
> > +	halt='use VIR_STRCAT, not strcat'				\
> > +	  $(_sc_search_regexp)
> > +
> > # Prefer virSetUIDGID.
> > sc_prohibit_setuid:
> > 	@prohibit='\<set(re)?[ug]id\> *\('				\
> > @@ -994,12 +999,6 @@ sc_prohibit_not_streq:
> > 	halt='Use STRNEQ instead of !STREQ and STREQ instead of !STRNEQ'	\
> > 	  $(_sc_search_regexp)
> > 
> > -sc_prohibit_verbose_strcat:
> > -	@prohibit='strncat\([^,]*,\s+([^,]*),\s+strlen\(\1\)\)'     \
> > -	in_vc_files='\.[ch]$$'                                      \
> > -	halt='Use strcat(a, b) instead of strncat(a, b, strlen(b))' \
> > -	  $(_sc_search_regexp)
> > -
> > # Ensure that each .c file containing a "main" function also
> > # calls virGettextInitialize
> > sc_gettext_init:
> > @@ -1134,6 +1133,9 @@ exclude_file_name_regexp--sc_prohibit_asprintf = \
> > exclude_file_name_regexp--sc_prohibit_strdup = \
> >   ^(docs/|examples/|src/util/virstring\.c|tests/vir(netserverclient|cgroup)mock.c$$)
> > 
> > +exclude_file_name_regexp--sc_prohibit_strcat = \
> > +  ^(docs/|src/util/virstring\.c|tests/virstringtest\.c)$$
> 
> why virstringtest.c?
> 
> > +
> > exclude_file_name_regexp--sc_prohibit_close = \
> >   (\.p[yl]$$|\.spec\.in$$|^docs/|^(src/util/virfile\.c|src/libvirt-stream\.c|tests/vir.+mock\.c)$$)
> > 
> > diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c
> > index 756c62e908..5e006a980a 100644
> > --- a/src/storage/storage_backend_logical.c
> > +++ b/src/storage/storage_backend_logical.c
> > @@ -201,11 +201,11 @@ virStorageBackendLogicalParseVolExtents(virStorageVolDefPtr vol,
> >     /* Allocate space for 'nextents' regex_unit strings plus a comma for each */
> >     if (VIR_ALLOC_N(regex, nextents * (strlen(regex_unit) + 1) + 1) < 0)
> >         goto cleanup;
> > -    strcat(regex, regex_unit);
> > +    VIR_STRCAT_INPLACE(regex, regex_unit);
> >     for (i = 1; i < nextents; i++) {
> >         /* "," is the separator of "devices" field */
> > -        strcat(regex, ",");
> > -        strcat(regex, regex_unit);
> > +        VIR_STRCAT_INPLACE(regex, ",");
> > +        VIR_STRCAT_INPLACE(regex, regex_unit);
> >     }
> > 
> >     if (VIR_ALLOC(reg) < 0)
> > diff --git a/src/test/test_driver.c b/src/test/test_driver.c
> > index 5fef3f10b9..be887ec1bb 100644
> > --- a/src/test/test_driver.c
> > +++ b/src/test/test_driver.c
> > @@ -699,7 +699,7 @@ static char *testBuildFilename(const char *relativeTo,
> >             VIR_FREE(absFile);
> >             return NULL;
> >         }
> > -        strcat(absFile, filename);
> > +        ignore_value(VIR_STRCAT_INPLACE(absFile, filename));
> >         return absFile;
> >     } else {
> >         ignore_value(VIR_STRDUP(ret, filename));
> > diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
> > index 5aa1db5b14..e8210ca6eb 100644
> > --- a/src/util/vircgroup.c
> > +++ b/src/util/vircgroup.c
> > @@ -1299,10 +1299,8 @@ virCgroupSetPartitionSuffix(const char *path, char **res)
> >          */
> >         if (STRNEQ(tokens[i], "") &&
> >             !strchr(tokens[i], '.')) {
> > -            if (VIR_REALLOC_N(tokens[i],
> > -                              strlen(tokens[i]) + strlen(".partition") + 1) < 0)
> > +            if (VIR_STRCAT(tokens[i], ".partition") < 0)
> >                 goto cleanup;
> > -            strcat(tokens[i], ".partition");
> 
> Not counting the rest of your patches, just for now, is this the only
> place the VIR_STRCAT adds value?  This makes me even more cautious about
> the patches.

That code could be rewritten with virAsprintf for clarity eg

           char *part;
	   if (virAsprintf(&part, "%s.partition", tokens[i]) < 0)
	        goto cleanup;
           VIR_FREE(tokens[i]);
	   tokens[i] = part;

No, it doesn't make it shorter, but I think it makes it clearer as
to what we're actually doing here.

Regards,
Daniel
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