mirror_zfs/module/os/freebsd/spl/spl_misc.c
Richard Yao 55d7afa4ad
Reduce false positives from Static Analyzers
Both Clang's Static Analyzer and Synopsys' Coverity would ignore
assertions. Following Clang's advice, we annotate our assertions:

https://clang-analyzer.llvm.org/annotations.html#custom_assertions

This makes both Clang's Static Analyzer and Coverity properly identify
assertions. This change reduced Clang's reported defects from 246 to
180. It also reduced the false positives reported by Coverityi by 10,
while enabling Coverity to find 9 more defects that previously were
false negatives.

A couple examples of this would be CID-1524417 and CID-1524423. After
submitting a build to coverity with the modified assertions, CID-1524417
disappeared while the report for CID-1524423 no longer claimed that the
assertion tripped.

Coincidentally, it turns out that it is possible to more accurately
annotate our headers than the Coverity modelling file permits in the
case of format strings. Since we can do that and this patch annotates
headers whenever `__coverity_panic__()` would have been used in the
model file, we drop all models that use `__coverity_panic__()` from the
model file.

Upon seeing the success in eliminating false positives involving
assertions, it occurred to me that we could also modify our headers to
eliminate coverity's false positives involving byte swaps. We now have
coverity specific byteswap macros, that do nothing, to disable
Coverity's false positives when we do byte swaps. This allowed us to
also drop the byteswap definitions from the model file.

Lastly, a model file update has been done beyond the mentioned
deletions:

 * The definitions of `umem_alloc_aligned()`, `umem_alloc()` andi
   `umem_zalloc()` were originally implemented in a way that was
   intended to inform coverity that when KM_SLEEP has been passed these
   functions, they do not return NULL. A small error in how this was
   done was found, so we correct it.

 * Definitions for umem_cache_alloc() and umem_cache_free() have been
   added.

In practice, no false positives were avoided by making these changes,
but in the interest of correctness from future coverity builds, we make
them anyway.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13902
2022-09-30 15:30:12 -07:00

110 lines
2.8 KiB
C

/*
* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/limits.h>
#include <sys/misc.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/zfs_context.h>
static struct opensolaris_utsname hw_utsname = {
.machine = MACHINE
};
utsname_t *
utsname(void)
{
return (&hw_utsname);
}
static void
opensolaris_utsname_init(void *arg)
{
hw_utsname.sysname = ostype;
hw_utsname.nodename = prison0.pr_hostname;
hw_utsname.release = osrelease;
snprintf(hw_utsname.version, sizeof (hw_utsname.version),
"%d", osreldate);
}
char *
kmem_strdup(const char *s)
{
char *buf;
buf = kmem_alloc(strlen(s) + 1, KM_SLEEP);
strcpy(buf, s);
return (buf);
}
int
ddi_copyin(const void *from, void *to, size_t len, int flags)
{
/* Fake ioctl() issued by kernel, 'from' is a kernel address */
if (flags & FKIOCTL) {
memcpy(to, from, len);
return (0);
}
return (copyin(from, to, len));
}
int
ddi_copyout(const void *from, void *to, size_t len, int flags)
{
/* Fake ioctl() issued by kernel, 'from' is a kernel address */
if (flags & FKIOCTL) {
memcpy(to, from, len);
return (0);
}
return (copyout(from, to, len));
}
void
spl_panic(const char *file, const char *func, int line, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vpanic(fmt, ap);
va_end(ap);
}
SYSINIT(opensolaris_utsname_init, SI_SUB_TUNABLES, SI_ORDER_ANY,
opensolaris_utsname_init, NULL);