Bug Summary

File:src/usr.bin/ktrace/ktrace.c
Warning:line 154, column 2
Value stored to 'argc' 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 ktrace.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.bin/ktrace/obj -resource-dir /usr/local/lib/clang/13.0.0 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.bin/ktrace/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.bin/ktrace/ktrace.c
1/* $OpenBSD: ktrace.c,v 1.38 2021/09/01 15:54:40 deraadt Exp $ */
2/* $NetBSD: ktrace.c,v 1.4 1995/08/31 23:01:44 jtc Exp $ */
3
4/*-
5 * Copyright (c) 1988, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/param.h> /* MAXCOMLEN */
34#include <sys/types.h>
35#include <sys/signal.h>
36#include <sys/stat.h>
37#include <sys/time.h>
38#include <sys/uio.h>
39#include <sys/ktrace.h>
40
41#include <err.h>
42#include <errno(*__errno()).h>
43#include <fcntl.h>
44#include <stdlib.h>
45#include <limits.h>
46#include <stdio.h>
47#include <string.h>
48#include <unistd.h>
49
50#include "ktrace.h"
51#include "extern.h"
52
53extern char *__progname;
54
55static int rpid(const char *);
56static void no_ktrace(int);
57static void usage(void);
58
59int is_ltrace;
60
61int
62main(int argc, char *argv[])
63{
64 enum { NOTSET, CLEAR, CLEARALL } clear;
65 int append, ch, fd, inherit, ops, pidset, trpoints;
66 pid_t pid;
67 char *tracefile, *tracespec;
68 mode_t omask;
69 struct stat sb;
70
71 is_ltrace = strcmp(__progname, "ltrace") == 0;
72
73 clear = NOTSET;
74 append = ops = pidset = inherit = pid = 0;
75 trpoints = is_ltrace ? KTRFAC_USER(1<<9) : DEF_POINTS((1<<1) | (1<<2) | (1<<3) | (1<<4) | (
1<<5) | (1<<8) | (1<<9) | (1<<10) | (
1<<12));
76 tracefile = DEF_TRACEFILE"ktrace.out";
77 tracespec = NULL((void *)0);
78
79 if (is_ltrace) {
80 while ((ch = getopt(argc, argv, "af:it:u:")) != -1)
81 switch ((char)ch) {
82 case 'a':
83 append = 1;
84 break;
85 case 'f':
86 tracefile = optarg;
87 break;
88 case 'i':
89 inherit = 1;
90 break;
91 case 't':
92 trpoints = getpoints(optarg, KTRFAC_USER(1<<9));
93 if (trpoints < 0) {
94 warnx("unknown facility in %s", optarg);
95 usage();
96 }
97 break;
98 case 'u':
99 tracespec = optarg;
100 break;
101 default:
102 usage();
103 }
104 } else {
105 while ((ch = getopt(argc, argv, "aBCcdf:g:ip:t:T")) != -1)
106 switch ((char)ch) {
107 case 'a':
108 append = 1;
109 break;
110 case 'B':
111 putenv("LD_BIND_NOW=");
112 break;
113 case 'C':
114 clear = CLEARALL;
115 tracefile = NULL((void *)0);
116 pidset = 1;
117 break;
118 case 'c':
119 clear = CLEAR;
120 break;
121 case 'd':
122 ops |= KTRFLAG_DESCEND4;
123 break;
124 case 'f':
125 tracefile = optarg;
126 break;
127 case 'g':
128 pid = -rpid(optarg);
129 pidset = 1;
130 break;
131 case 'i':
132 inherit = 1;
133 break;
134 case 'p':
135 pid = rpid(optarg);
136 pidset = 1;
137 break;
138 case 't':
139 trpoints = getpoints(optarg, DEF_POINTS((1<<1) | (1<<2) | (1<<3) | (1<<4) | (
1<<5) | (1<<8) | (1<<9) | (1<<10) | (
1<<12)));
140 if (trpoints < 0) {
141 warnx("unknown facility in %s", optarg);
142 usage();
143 }
144 break;
145 case 'T':
146 putenv("LIBC_NOUSERTC=");
147 break;
148 default:
149 usage();
150 }
151 }
152
153 argv += optind;
154 argc -= optind;
Value stored to 'argc' is never read
155
156 if ((pidset && *argv) || (!pidset && !*argv && clear != CLEAR))
157 usage();
158
159 if (inherit)
160 trpoints |= KTRFAC_INHERIT0x40000000;
161
162 (void)signal(SIGSYS12, no_ktrace);
163 if (clear != NOTSET) {
164 if (clear == CLEARALL) {
165 ops = KTROP_CLEAR1 | KTRFLAG_DESCEND4;
166 trpoints = ALL_POINTS(((1<<1) | (1<<2) | (1<<3) | (1<<4) |
(1<<5) | (1<<8) | (1<<9) | (1<<10) |
(1<<12)) | (1<<11));
167 pid = 1;
168 } else
169 ops |= pid ? KTROP_CLEAR1 : KTROP_CLEARFILE2;
170
171 if (ktrace(tracefile, ops, trpoints, pid) == -1) {
172 if (errno(*__errno()) == ESRCH3)
173 err(1, "%d", pid);
174 err(1, "%s", tracefile);
175 }
176 exit(0);
177 }
178
179 omask = umask(S_IRWXG0000070|S_IRWXO0000007);
180 if (append) {
181 if ((fd = open(tracefile, O_CREAT0x0200 | O_WRONLY0x0001, DEFFILEMODE(0000400|0000200|0000040|0000020|0000004|0000002))) == -1)
182 err(1, "%s", tracefile);
183 if (fstat(fd, &sb) != 0 || sb.st_uid != getuid())
184 errx(1, "Refuse to append to %s: not owned by you.",
185 tracefile);
186 } else {
187 if (unlink(tracefile) == -1 && errno(*__errno()) != ENOENT2)
188 err(1, "unlink %s", tracefile);
189 if ((fd = open(tracefile, O_CREAT0x0200 | O_EXCL0x0800 | O_WRONLY0x0001,
190 DEFFILEMODE(0000400|0000200|0000040|0000020|0000004|0000002))) == -1)
191 err(1, "%s", tracefile);
192 }
193 (void)umask(omask);
194 (void)close(fd);
195
196 if (*argv) {
197 if (is_ltrace) {
198 if (setenv("LD_TRACE_PLT", inherit ? "i" : "", 1) < 0)
199 err(1, "setenv(LD_TRACE_PLT)");
200 if (tracespec &&
201 setenv("LD_TRACE_PLTSPEC", tracespec, 1) < 0)
202 err(1, "setenv(LD_TRACE_PLTSPEC)");
203 }
204 if (ktrace(tracefile, ops, trpoints, getpid()) == -1)
205 err(1, "%s", tracefile);
206 execvp(argv[0], &argv[0]);
207 err(1, "exec of '%s' failed", argv[0]);
208 }
209 else if (ktrace(tracefile, ops, trpoints, pid) == -1) {
210 if (errno(*__errno()) == ESRCH3)
211 err(1, "%d", pid);
212 err(1, "%s", tracefile);
213 }
214 exit(0);
215}
216
217static int
218rpid(const char *p)
219{
220 const char *errstr;
221 static int first;
222 pid_t pid;
223
224 if (first++) {
225 warnx("only one -g or -p flag is permitted.");
226 usage();
227 }
228 if (!*p) {
229 warnx("illegal process id.");
230 usage();
231 }
232 pid = strtonum(p, 1, INT_MAX2147483647, &errstr);
233 if (errstr) {
234 warnx("illegal process id: %s", errstr);
235 usage();
236 }
237 return pid;
238}
239
240static void
241usage(void)
242{
243 if (is_ltrace)
244 fprintf(stderr(&__sF[2]), "usage: %s [-ai] [-f trfile] [-t trstr]"
245 " [-u trspec] command\n",
246 __progname);
247 else
248 fprintf(stderr(&__sF[2]), "usage: %s [-aCcdi] [-f trfile] [-g pgid]"
249 " [-p pid] [-t trstr]\n"
250 " %s [-aBdiT] [-f trfile] [-t trstr] command\n",
251 __progname, __progname);
252 exit(1);
253}
254
255/* ARGSUSED */
256static void
257no_ktrace(int signo)
258{
259 dprintf(STDERR_FILENO2,
260"error:\tktrace() system call not supported in the running kernel\n\tre-compile kernel with 'option KTRACE'\n");
261 _exit(1);
262}