Bug Summary

File:src/usr.sbin/makefs/ffs/ufs_bmap.c
Warning:line 121, column 3
Value stored to 'blockcnt' is never read

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ufs_bmap.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/usr.sbin/makefs/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/usr.sbin/makefs -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.sbin/makefs/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/usr.sbin/makefs/ffs/ufs_bmap.c
1/* $OpenBSD: ufs_bmap.c,v 1.7 2021/10/06 00:40:41 deraadt Exp $ */
2/* $NetBSD: ufs_bmap.c,v 1.18 2013/06/19 17:51:27 dholland Exp $ */
3/* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */
4
5/*
6 * Copyright (c) 1989, 1991, 1993
7 * The Regents of the University of California. All rights reserved.
8 * (c) UNIX System Laboratories, Inc.
9 * All or some portions of this file are derived from material licensed
10 * to the University of California by American Telephone and Telegraph
11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
12 * the permission of UNIX System Laboratories, Inc.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95
39 */
40
41#include <sys/time.h>
42
43#include <assert.h>
44#include <errno(*__errno()).h>
45#include <strings.h>
46
47#include "makefs.h"
48
49#include <ufs/ufs/dinode.h>
50#include <ufs/ffs/fs.h>
51
52#include "ffs/ufs_inode.h"
53#include "ffs/ffs_extern.h"
54
55/*
56 * Create an array of logical block number/offset pairs which represent the
57 * path of indirect blocks required to access a data block. The first "pair"
58 * contains the logical block number of the appropriate single, double or
59 * triple indirect block and the offset into the inode indirect block array.
60 * Note, the logical block number of the inode single/double/triple indirect
61 * block appears twice in the array, once with the offset into the i_ffs_ib and
62 * once with the offset into the page itself.
63 */
64int
65ufs_getlbns(struct inode *ip, daddr_t bn, struct indir *ap, int *nump)
66{
67 daddr_t metalbn, realbn;
68 int64_t blockcnt;
69 int lbc;
70 int i, numlevels, off;
71 u_long lognindir;
72
73 lognindir = ffs(NINDIR(ip->i_fs)((ip->i_fs)->fs_nindir)) - 1;
74 if (nump)
75 *nump = 0;
76 numlevels = 0;
77 realbn = bn;
78 if ((long)bn < 0)
79 bn = -(long)bn;
80
81 assert (bn >= NDADDR)((bn >= 12) ? (void)0 : __assert2("/usr/src/usr.sbin/makefs/ffs/ufs_bmap.c"
, 81, __func__, "bn >= NDADDR"))
;
82
83 /*
84 * Determine the number of levels of indirection. After this loop
85 * is done, blockcnt indicates the number of data blocks possible
86 * at the given level of indirection, and NIADDR - i is the number
87 * of levels of indirection needed to locate the requested block.
88 */
89
90 bn -= NDADDR12;
91 for (lbc = 0, i = NIADDR3;; i--, bn -= blockcnt) {
92 if (i == 0)
93 return (EFBIG27);
94
95 lbc += lognindir;
96 blockcnt = (int64_t)1 << lbc;
97
98 if (bn < blockcnt)
99 break;
100 }
101
102 /* Calculate the address of the first meta-block. */
103 metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + NIADDR3 - i);
104
105 /*
106 * At each iteration, off is the offset into the bap array which is
107 * an array of disk addresses at the current level of indirection.
108 * The logical block number and the offset in that block are stored
109 * into the argument array.
110 */
111 ap->in_lbn = metalbn;
112 ap->in_off = off = NIADDR3 - i;
113 ap->in_exists = 0;
114 ap++;
115 for (++numlevels; i <= NIADDR3; i++) {
116 /* If searching for a meta-data block, quit when found. */
117 if (metalbn == realbn)
118 break;
119
120 lbc -= lognindir;
121 blockcnt = (int64_t)1 << lbc;
Value stored to 'blockcnt' is never read
122 off = (bn >> lbc) & (NINDIR(ip->i_fs)((ip->i_fs)->fs_nindir) - 1);
123
124 ++numlevels;
125 ap->in_lbn = metalbn;
126 ap->in_off = off;
127 ap->in_exists = 0;
128 ++ap;
129
130 metalbn -= -1 + (off << lbc);
131 }
132 if (nump)
133 *nump = numlevels;
134 return (0);
135}