Bug Summary

File:root/firefox-clang/media/ffvpx/libavutil/fifo.c
Warning:line 171, column 13
Null pointer passed to 2nd parameter expecting 'nonnull'

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -O2 -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name fifo.c -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 -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -ffp-contract=off -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/root/firefox-clang/obj-x86_64-pc-linux-gnu/media/ffvpx/libavutil -fcoverage-compilation-dir=/root/firefox-clang/obj-x86_64-pc-linux-gnu/media/ffvpx/libavutil -resource-dir /usr/lib/llvm-23/lib/clang/23 -include /root/firefox-clang/obj-x86_64-pc-linux-gnu/mozilla-config.h -include libavutil_visibility.h -U _FORTIFY_SOURCE -D _FORTIFY_SOURCE=2 -D DEBUG=1 -D HAVE_AV_CONFIG_H -D ASSERT_LEVEL=2 -I /root/firefox-clang/media/ffvpx/libavutil -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/media/ffvpx/libavutil -I /root/firefox-clang/third_party/khronos/vulkan-headers/include -I /root/firefox-clang/media/mozva -I /root/firefox-clang/media/ffvpx -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nspr -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nss -D MOZILLA_CLIENT -internal-isystem /usr/lib/llvm-23/lib/clang/23/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/16/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -Wno-error=tautological-type-limit-compare -Wno-range-loop-analysis -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=free-nonheap-object -Wno-error=atomic-alignment -Wno-error=deprecated-builtins -Wno-psabi -Wno-error=builtin-macro-redefined -Wno-unknown-warning-option -Wno-character-conversion -Wno-parentheses -Wno-pointer-sign -Wno-sign-compare -Wno-switch -Wno-type-limits -Wno-unused-function -Wno-deprecated-declarations -Wno-absolute-value -Wno-incompatible-pointer-types -Wno-string-conversion -Wno-visibility -ferror-limit 19 -fstrict-flex-arrays=1 -stack-protector 2 -fstack-clash-protection -ftrivial-auto-var-init=pattern -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fdiagnostics-absolute-paths -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -mllvm -dwarf-linkage-names=Abstract -faddrsig -fdwarf2-cfi-asm -o /tmp/scan-build-2026-09-01-224014-2642839-1 -x c /root/firefox-clang/media/ffvpx/libavutil/fifo.c
1/*
2 * a very simple circular buffer FIFO implementation
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 * Copyright (c) 2006 Roman Shaposhnik
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include <stdint.h>
24#include <string.h>
25
26#include "avassert.h"
27#include "error.h"
28#include "fifo.h"
29#include "macros.h"
30#include "mem.h"
31
32// by default the FIFO can be auto-grown to 1MB
33#define AUTO_GROW_DEFAULT_BYTES(1024 * 1024) (1024 * 1024)
34
35struct AVFifo {
36 uint8_t *buffer;
37
38 size_t elem_size, nb_elems;
39 size_t offset_r, offset_w;
40 // distinguishes the ambiguous situation offset_r == offset_w
41 int is_empty;
42
43 unsigned int flags;
44 size_t auto_grow_limit;
45};
46
47AVFifo *av_fifo_alloc2(size_t nb_elems, size_t elem_size,
48 unsigned int flags)
49{
50 AVFifo *f;
51 void *buffer = NULL((void*)0);
52
53 if (!elem_size)
54 return NULL((void*)0);
55
56 if (nb_elems) {
57 buffer = av_realloc_array(NULL((void*)0), nb_elems, elem_size);
58 if (!buffer)
59 return NULL((void*)0);
60 }
61 f = av_mallocz(sizeof(*f));
62 if (!f) {
63 av_free(buffer);
64 return NULL((void*)0);
65 }
66 f->buffer = buffer;
67 f->nb_elems = nb_elems;
68 f->elem_size = elem_size;
69 f->is_empty = 1;
70
71 f->flags = flags;
72 f->auto_grow_limit = FFMAX(AUTO_GROW_DEFAULT_BYTES / elem_size, 1)(((1024 * 1024) / elem_size) > (1) ? ((1024 * 1024) / elem_size
) : (1));
73
74 return f;
75}
76
77void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems)
78{
79 f->auto_grow_limit = max_elems;
80}
81
82size_t av_fifo_elem_size(const AVFifo *f)
83{
84 return f->elem_size;
85}
86
87size_t av_fifo_can_read(const AVFifo *f)
88{
89 if (f->offset_w <= f->offset_r && !f->is_empty)
90 return f->nb_elems - f->offset_r + f->offset_w;
91 return f->offset_w - f->offset_r;
92}
93
94size_t av_fifo_can_write(const AVFifo *f)
95{
96 return f->nb_elems - av_fifo_can_read(f);
97}
98
99int av_fifo_grow2(AVFifo *f, size_t inc)
100{
101 uint8_t *tmp;
102
103 if (inc > SIZE_MAX(18446744073709551615UL) - f->nb_elems)
104 return AVERROR(EINVAL)(-(22));
105
106 tmp = av_realloc_array(f->buffer, f->nb_elems + inc, f->elem_size);
107 if (!tmp)
108 return AVERROR(ENOMEM)(-(12));
109 f->buffer = tmp;
110
111 // move the data from the beginning of the ring buffer
112 // to the newly allocated space
113 if (f->offset_w <= f->offset_r && !f->is_empty) {
114 const size_t copy = FFMIN(inc, f->offset_w)((inc) > (f->offset_w) ? (f->offset_w) : (inc));
115 memcpy(tmp + f->nb_elems * f->elem_size, tmp, copy * f->elem_size);
116 if (copy < f->offset_w) {
117 memmove(tmp, tmp + copy * f->elem_size,
118 (f->offset_w - copy) * f->elem_size);
119 f->offset_w -= copy;
120 } else
121 f->offset_w = copy == inc ? 0 : f->nb_elems + copy;
122 }
123
124 f->nb_elems += inc;
125
126 return 0;
127}
128
129static int fifo_check_space(AVFifo *f, size_t to_write)
130{
131 const size_t can_write = av_fifo_can_write(f);
132 const size_t need_grow = to_write > can_write ? to_write - can_write : 0;
133 size_t can_grow;
134
135 if (!need_grow)
136 return 0;
137
138 can_grow = f->auto_grow_limit > f->nb_elems ?
139 f->auto_grow_limit - f->nb_elems : 0;
140 if ((f->flags & AV_FIFO_FLAG_AUTO_GROW(1 << 0)) && need_grow <= can_grow) {
141 // allocate a bit more than necessary, if we can
142 const size_t inc = (need_grow < can_grow / 2 ) ? need_grow * 2 : can_grow;
143 return av_fifo_grow2(f, inc);
144 }
145
146 return AVERROR(ENOSPC)(-(28));
147}
148
149static int fifo_write_common(AVFifo *f, const uint8_t *buf, size_t *nb_elems,
150 AVFifoCB read_cb, void *opaque)
151{
152 size_t to_write = *nb_elems;
153 size_t offset_w;
154 int ret = 0;
155
156 ret = fifo_check_space(f, to_write);
157 if (ret
2.1
'ret' is >= 0
 < 0)
3
←
Taking false branch
→
158 return ret;
159
160 offset_w = f->offset_w;
161
162 while (to_write > 0) {
4
←
Assuming 'to_write' is > 0
→
163 size_t len = FFMIN(f->nb_elems - offset_w, to_write)((f->nb_elems - offset_w) > (to_write) ? (to_write) : (
f->nb_elems - offset_w));
5
←
Loop condition is true. Entering loop body
→
6
←
Assuming the condition is true
→
7
←
'?' condition is true
→
164 uint8_t *wptr = f->buffer + offset_w * f->elem_size;
165
166 if (read_cb) {
8
←
Assuming 'read_cb' is null
→
9
←
Taking false branch
→
167 ret = read_cb(opaque, wptr, &len);
168 if (ret < 0 || len == 0)
169 break;
170 } else {
171 memcpy(wptr, buf, len * f->elem_size);
10
←
Null pointer passed to 2nd parameter expecting 'nonnull'
172 buf += len * f->elem_size;
173 }
174 offset_w += len;
175 if (offset_w >= f->nb_elems)
176 offset_w = 0;
177 to_write -= len;
178 }
179 f->offset_w = offset_w;
180
181 if (*nb_elems != to_write)
182 f->is_empty = 0;
183 *nb_elems -= to_write;
184
185 return ret;
186}
187
188int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems)
189{
190 return fifo_write_common(f, buf, &nb_elems, NULL((void*)0), NULL((void*)0));
191}
192
193int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb,
194 void *opaque, size_t *nb_elems)
195{
196 return fifo_write_common(f, NULL((void*)0), nb_elems, read_cb, opaque);
1
Passing null pointer value via 2nd parameter 'buf'
→
2
←
Calling 'fifo_write_common'
→
197}
198
199static int fifo_peek_common(const AVFifo *f, uint8_t *buf, size_t *nb_elems,
200 size_t offset, AVFifoCB write_cb, void *opaque)
201{
202 size_t to_read = *nb_elems;
203 size_t offset_r = f->offset_r;
204 size_t can_read = av_fifo_can_read(f);
205 int ret = 0;
206
207 if (offset > can_read || to_read > can_read - offset) {
208 *nb_elems = 0;
209 return AVERROR(EINVAL)(-(22));
210 }
211
212 if (offset_r >= f->nb_elems - offset)
213 offset_r -= f->nb_elems - offset;
214 else
215 offset_r += offset;
216
217 while (to_read > 0) {
218 size_t len = FFMIN(f->nb_elems - offset_r, to_read)((f->nb_elems - offset_r) > (to_read) ? (to_read) : (f->
nb_elems - offset_r));
219 uint8_t *rptr = f->buffer + offset_r * f->elem_size;
220
221 if (write_cb) {
222 ret = write_cb(opaque, rptr, &len);
223 if (ret < 0 || len == 0)
224 break;
225 } else {
226 memcpy(buf, rptr, len * f->elem_size);
227 buf += len * f->elem_size;
228 }
229 offset_r += len;
230 if (offset_r >= f->nb_elems)
231 offset_r = 0;
232 to_read -= len;
233 }
234
235 *nb_elems -= to_read;
236
237 return ret;
238}
239
240int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems)
241{
242 int ret = fifo_peek_common(f, buf, &nb_elems, 0, NULL((void*)0), NULL((void*)0));
243 av_fifo_drain2(f, nb_elems);
244 return ret;
245}
246
247int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb,
248 void *opaque, size_t *nb_elems)
249{
250 int ret = fifo_peek_common(f, NULL((void*)0), nb_elems, 0, write_cb, opaque);
251 av_fifo_drain2(f, *nb_elems);
252 return ret;
253}
254
255int av_fifo_peek(const AVFifo *f, void *buf, size_t nb_elems, size_t offset)
256{
257 return fifo_peek_common(f, buf, &nb_elems, offset, NULL((void*)0), NULL((void*)0));
258}
259
260int av_fifo_peek_to_cb(const AVFifo *f, AVFifoCB write_cb, void *opaque,
261 size_t *nb_elems, size_t offset)
262{
263 return fifo_peek_common(f, NULL((void*)0), nb_elems, offset, write_cb, opaque);
264}
265
266void av_fifo_drain2(AVFifo *f, size_t size)
267{
268 const size_t cur_size = av_fifo_can_read(f);
269
270 av_assert0(cur_size >= size)do { if (!(cur_size >= size)) { av_log(((void*)0), 0, "Assertion %s failed at %s:%d\n"
, "cur_size >= size", "/root/firefox-clang/media/ffvpx/libavutil/fifo.c"
, 270); abort(); } } while (0);
271 if (cur_size == size)
272 f->is_empty = 1;
273
274 if (f->offset_r >= f->nb_elems - size)
275 f->offset_r -= f->nb_elems - size;
276 else
277 f->offset_r += size;
278}
279
280void av_fifo_reset2(AVFifo *f)
281{
282 f->offset_r = f->offset_w = 0;
283 f->is_empty = 1;
284}
285
286void av_fifo_freep2(AVFifo **f)
287{
288 if (*f) {
289 av_freep(&(*f)->buffer);
290 av_freep(f);
291 }
292}