Bug Summary

File:src/lib/libelf/libelf_open.c
Warning:line 57, column 2
Value stored to 'readsz' 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 libelf_open.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 -fhalf-no-semantic-interposition -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/lib/libelf/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/lib/libelf -D PIC -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/lib/libelf/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/lib/libelf/libelf_open.c
1/*-
2 * Copyright (c) 2006,2008-2011 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/types.h>
28#include <sys/stat.h>
29
30#include <assert.h>
31#include <errno(*__errno()).h>
32#include <libelf.h>
33#include <stdlib.h>
34#include <unistd.h>
35
36#include "_libelf.h"
37
38#if ELFTC_HAVE_MMAP1
39#include <sys/mman.h>
40#endif
41
42ELFTC_VCSID("$Id: libelf_open.c,v 1.1 2019/02/01 05:27:38 jsg Exp $")__asm__(".ident\t\"" "$Id: libelf_open.c,v 1.1 2019/02/01 05:27:38 jsg Exp $"
"\"");
43
44#define _LIBELF_INITSIZE(64*1024) (64*1024)
45
46/*
47 * Read from a device file, pipe or socket.
48 */
49static void *
50_libelf_read_special_file(int fd, size_t *fsz)
51{
52 ssize_t readsz;
53 size_t bufsz, datasz;
54 unsigned char *buf, *t;
55
56 datasz = 0;
57 readsz = 0;
Value stored to 'readsz' is never read
58 bufsz = _LIBELF_INITSIZE(64*1024);
59 if ((buf = malloc(bufsz)) == NULL((void *)0))
60 goto resourceerror;
61
62 /*
63 * Read data from the file descriptor till we reach EOF, or
64 * till an error is encountered.
65 */
66 do {
67 /* Check if we need to expand the data buffer. */
68 if (datasz == bufsz) {
69 bufsz *= 2;
70 if ((t = realloc(buf, bufsz)) == NULL((void *)0))
71 goto resourceerror;
72 buf = t;
73 }
74
75 do {
76 assert(bufsz - datasz > 0)((bufsz - datasz > 0) ? (void)0 : __assert2("/usr/src/lib/libelf/libelf_open.c"
, 76, __func__, "bufsz - datasz > 0"));
77 t = buf + datasz;
78 if ((readsz = read(fd, t, bufsz - datasz)) <= 0)
79 break;
80 datasz += (size_t) readsz;
81 } while (datasz < bufsz);
82
83 } while (readsz > 0);
84
85 if (readsz < 0) {
86 LIBELF_SET_ERROR(IO, errno)do { (_libelf.libelf_error) = (((ELF_E_IO) & 0xFF) | ((((
*__errno()))) << 8)); } while (0);
87 goto error;
88 }
89
90 assert(readsz == 0)((readsz == 0) ? (void)0 : __assert2("/usr/src/lib/libelf/libelf_open.c"
, 90, __func__, "readsz == 0"));
91
92 /*
93 * Free up extra buffer space.
94 */
95 if (bufsz > datasz) {
96 if (datasz > 0) {
97 if ((t = realloc(buf, datasz)) == NULL((void *)0))
98 goto resourceerror;
99 buf = t;
100 } else { /* Zero bytes read. */
101 LIBELF_SET_ERROR(ARGUMENT, 0)do { (_libelf.libelf_error) = (((ELF_E_ARGUMENT) & 0xFF) |
(((0)) << 8)); } while (0);
102 free(buf);
103 buf = NULL((void *)0);
104 }
105 }
106
107 *fsz = datasz;
108 return (buf);
109
110resourceerror:
111 LIBELF_SET_ERROR(RESOURCE, 0)do { (_libelf.libelf_error) = (((ELF_E_RESOURCE) & 0xFF) |
(((0)) << 8)); } while (0);
112error:
113 if (buf != NULL((void *)0))
114 free(buf);
115 return (NULL((void *)0));
116}
117
118/*
119 * Read the contents of the file referenced by the file descriptor
120 * 'fd'.
121 */
122
123Elf *
124_libelf_open_object(int fd, Elf_Cmd c, int reporterror)
125{
126 Elf *e;
127 void *m;
128 mode_t mode;
129 size_t fsize;
130 struct stat sb;
131 unsigned int flags;
132
133 assert(c == ELF_C_READ || c == ELF_C_RDWR || c == ELF_C_WRITE)((c == ELF_C_READ || c == ELF_C_RDWR || c == ELF_C_WRITE) ? (
void)0 : __assert2("/usr/src/lib/libelf/libelf_open.c", 133, __func__
, "c == ELF_C_READ || c == ELF_C_RDWR || c == ELF_C_WRITE"));
134
135 if (fstat(fd, &sb) < 0) {
136 LIBELF_SET_ERROR(IO, errno)do { (_libelf.libelf_error) = (((ELF_E_IO) & 0xFF) | ((((
*__errno()))) << 8)); } while (0);
137 return (NULL((void *)0));
138 }
139
140 mode = sb.st_mode;
141 fsize = (size_t) sb.st_size;
142
143 /*
144 * Reject unsupported file types.
145 */
146 if (!S_ISREG(mode)((mode & 0170000) == 0100000) && !S_ISCHR(mode)((mode & 0170000) == 0020000) && !S_ISFIFO(mode)((mode & 0170000) == 0010000) &&
147 !S_ISSOCK(mode)((mode & 0170000) == 0140000)) {
148 LIBELF_SET_ERROR(ARGUMENT, 0)do { (_libelf.libelf_error) = (((ELF_E_ARGUMENT) & 0xFF) |
(((0)) << 8)); } while (0);
149 return (NULL((void *)0));
150 }
151
152 /*
153 * For ELF_C_WRITE mode, allocate and return a descriptor.
154 */
155 if (c == ELF_C_WRITE) {
156 if ((e = _libelf_allocate_elf()) != NULL((void *)0)) {
157 _libelf_init_elf(e, ELF_K_ELF);
158 e->e_byteorder = LIBELF_PRIVATE(byteorder)(_libelf.libelf_byteorder);
159 e->e_fd = fd;
160 e->e_cmd = c;
161 if (!S_ISREG(mode)((mode & 0170000) == 0100000))
162 e->e_flags |= LIBELF_F_SPECIAL_FILE0x400000U;
163 }
164
165 return (e);
166 }
167
168
169 /*
170 * ELF_C_READ and ELF_C_RDWR mode.
171 */
172 m = NULL((void *)0);
173 flags = 0;
174 if (S_ISREG(mode)((mode & 0170000) == 0100000)) {
175
176 /*
177 * Reject zero length files.
178 */
179 if (fsize == 0) {
180 LIBELF_SET_ERROR(ARGUMENT, 0)do { (_libelf.libelf_error) = (((ELF_E_ARGUMENT) & 0xFF) |
(((0)) << 8)); } while (0);
181 return (NULL((void *)0));
182 }
183
184#if ELFTC_HAVE_MMAP1
185 /*
186 * Always map regular files in with 'PROT_READ'
187 * permissions.
188 *
189 * For objects opened in ELF_C_RDWR mode, when
190 * elf_update(3) is called, we remove this mapping,
191 * write file data out using write(2), and map the new
192 * contents back.
193 */
194 m = mmap(NULL((void *)0), fsize, PROT_READ0x01, MAP_PRIVATE0x0002, fd, (off_t) 0);
195
196 if (m == MAP_FAILED((void *)-1))
197 m = NULL((void *)0);
198 else
199 flags = LIBELF_F_RAWFILE_MMAP0x100000U;
200#endif
201
202 /*
203 * Fallback to a read() if the call to mmap() failed,
204 * or if mmap() is not available.
205 */
206 if (m == NULL((void *)0)) {
207 if ((m = malloc(fsize)) == NULL((void *)0)) {
208 LIBELF_SET_ERROR(RESOURCE, 0)do { (_libelf.libelf_error) = (((ELF_E_RESOURCE) & 0xFF) |
(((0)) << 8)); } while (0);
209 return (NULL((void *)0));
210 }
211
212 if (read(fd, m, fsize) != (ssize_t) fsize) {
213 LIBELF_SET_ERROR(IO, errno)do { (_libelf.libelf_error) = (((ELF_E_IO) & 0xFF) | ((((
*__errno()))) << 8)); } while (0);
214 free(m);
215 return (NULL((void *)0));
216 }
217
218 flags = LIBELF_F_RAWFILE_MALLOC0x080000U;
219 }
220 } else if ((m = _libelf_read_special_file(fd, &fsize)) != NULL((void *)0))
221 flags = LIBELF_F_RAWFILE_MALLOC0x080000U | LIBELF_F_SPECIAL_FILE0x400000U;
222 else
223 return (NULL((void *)0));
224
225 if ((e = _libelf_memory(m, fsize, reporterror)) == NULL((void *)0)) {
226 assert((flags & LIBELF_F_RAWFILE_MALLOC) ||(((flags & 0x080000U) || (flags & 0x100000U)) ? (void
)0 : __assert2("/usr/src/lib/libelf/libelf_open.c", 227, __func__
, "(flags & LIBELF_F_RAWFILE_MALLOC) || (flags & LIBELF_F_RAWFILE_MMAP)"
))
227 (flags & LIBELF_F_RAWFILE_MMAP))(((flags & 0x080000U) || (flags & 0x100000U)) ? (void
)0 : __assert2("/usr/src/lib/libelf/libelf_open.c", 227, __func__
, "(flags & LIBELF_F_RAWFILE_MALLOC) || (flags & LIBELF_F_RAWFILE_MMAP)"
));
228 if (flags & LIBELF_F_RAWFILE_MALLOC0x080000U)
229 free(m);
230#if ELFTC_HAVE_MMAP1
231 else
232 (void) munmap(m, fsize);
233#endif
234 return (NULL((void *)0));
235 }
236
237 /* ar(1) archives aren't supported in RDWR mode. */
238 if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) {
239 (void) elf_end(e);
240 LIBELF_SET_ERROR(ARGUMENT, 0)do { (_libelf.libelf_error) = (((ELF_E_ARGUMENT) & 0xFF) |
(((0)) << 8)); } while (0);
241 return (NULL((void *)0));
242 }
243
244 e->e_flags |= flags;
245 e->e_fd = fd;
246 e->e_cmd = c;
247
248 return (e);
249}